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Port of Split (Croatia) - Port Information (ID: 35461)
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Split, Croatia Split, Croatia Croatia Split Port Information Selections South Port Map - Gradska Luka South Port Picture North Port Map - Bazen Vranjic Geographic Location Harbor as Haven Currents and Tides Visibility Hazardous Conditions Spring Summer Autumn Winter Protective/Mitigating Measures Moving to a New Anchorage Sortie/Remain in Port Scheduling Harbor Protection Local Hazardous Weather Conditions Wind Chill Table Heat Index Table Return To Ports List June, 1999 Dubrovnik Area Map South Port Map - Gradska Luka South Port Picture View from the north toward the breakwater. North Port Map - Bazen Vranjic Geographic Geographic Location Coordinates: 43° 30'N, 16° 27'E Split is located on the eastern Adriatic coast about 90 nm northwest of Dubrovnik, Croatia. Terrain of the Dinaric Alps rises steeply inland from Split, reaching heights of over 4000 ft (1300 m) 12 nm east of the city and over 2500 ft (762 m) within a few miles to the north and west. The mountain passes in the region facilitate extremely strong NE bora wind events during the latefall, winter and spring, which achieve gust-force hurricane intensities at various locations within thecity and port regions. The small port (Gradska Luka) on the south side of the city, has been used for berthing U. S. Navalvessels (destroyers and frigates) and as a location for Fleet Landing. Ships normally anchor a shortdistance southeast of the harbor entrance, or within Kastelanski Zalev, the large bay west of Splitand north of the island of Ciovo. Fleet Landing (normally established in Gradska Luka near the PortCaptains office on the northeasternmost pier), is often the preferred location. This position providesimmediate access to the old town, with its many historical attractions, including "Diocletion'sPalace," one of the most imposing Roman ruins in existence. Sjeverna Luka (North Port) is a bay onthe east side of Kastelanski Zalev, north of Split, and encompasses the major berthing locationsused by commercial interests and the military. It is the largest such group of berthing locations onthe Dalmatian coast. Berths for sea-going vessels are spread around the periphery of SjevernaLuka, from north through east, to south, in the following order: Kastel Sucurac, Bazen Solin,Bazen Vranjic (used by the U. S. and other military vessels of all nations), Bazen BrodogradilistaSplit, within the harbor of Uvala Supaval, Luka Lora (reserved for use by the Croatian Navy), and ,finally, Luka Poljud, which contains several small harbors. Bazen Vranjic (used by the U. S.) lieswithin a large industrial area, about a 15 minute taxi ride to the old town. A mountainous, narrowpeninsula (Croatian: poluotok), lies on the north side of Bazen Vranjic, with the town of Vranjic onthe western tip. This peninsula separates Bazen Vranjic from Bazen Solen, to the north. Coastersand grain carrying vessels discharge cargo on the north side of Bazen Vranjic. Military and otherdeep draft commercial vessels tie up mainly on the south side of the port, with the exception ofnorth side pier #6, which lies on the eastern extremity of the port. The south, port (Gradska Luka) isvery busy, especially during the summer, when 3 to 4 tourist cruisers arrive daily, with additional inter-island and car ferry traffic being conducted at the same time. For this reason docking of U. S. Naval vessels and other foreign military vessels during the summer is primarily conducted at thenorth port (Bazen Vranjic). Anchorage outside the south port, however, and transport of personnel in small boats for city visits, is feasible at all times, weather conditions permitting. Catamarans areavailable at Split for such transport. The winter season is more lax, with a passenger ship arriving only about once every two days, so that use of the port by destroyers and frigates during this periodis more feasible. Anchorage for the south port (Gradska Luka) is in Bracki Kanal approximately one to two milessoutheast of the breakwater (Croatian: lukobran) at depths ranging from 37 to 40 meters. Holding isconsidered very good, with a mud bottom. Somewhat further to the southeast (about 6.5 miles fromthe breakwater) is an anchorage reserved for ships with dangerous cargo (chemicals, etc.). There areseveral potential anchorages within Kastelanski Zalev and Sjeverna Luka for the U. S. Navy. Thepilot in coordination with the Port Authority, would more than likely make a selection based onknowledge of weather conditions and commercial traffic in the area at the time. However, the west-central portion of Kastelanski Zalev, where depths range from 27-35 m, is considered the primarylocation for military anchorage. Although winds from all directions raise a sea at this location,holding in mud is considered very good, and no problem with U. S. ships dragging anchor havebeen reported. A caution is advised, however, that a few rocky areas exist in that region, and that(except for summer) it is best to stay as far north of the north coast of Ciovo Island as possible, sinceboth the bora and scirocco are reported to blow stronger in this region than elsewhere in the bay. Ships coming northward up the coast from Ploce toward Split generally enter by way of the Bracki Kanal, the passageway between Brac Island and the mainland; ships entering from the south throughthe central Adriatic, enter by way of Splitska Vrata (Split gate), the passageway between Brac Islandand Solta Island. Entrance from the north is through Drvenicki Kanal. Entrance through Soltanski Kanal, southeast of Drvenicki Kanal, between Veliki (big) Drvenik and Solta Island, is discouragedbecause of shoals near mid-channel, and islets surrounded by shallow banks on both sides of thechannel. Entrance through this channel at night is particularly dangerous because of poor lighting. Pilots are usually requested to board prior to proceeding to anchorages or port harbors beforeentering the recommended passageways. VHF channel 16 is monitored continuously by the Harbor Master and Port Authority, generally for initial contact and emergencies. The pilots use channel 9,the Harbor Master, channel 10, and the Port Authority, channel 2. From anchorage positions southeast of Gradska Luka pilots can also be requested for ship movementeither into Gradska Luka, to anchorage in Kastelanski Zalev, or entrance for a pier position in BazenVranjic. Pilotage is required for all ships weighing over 500 tons and is arranged through the HarborAuthority at Split, normally giving 24 hours of advance notice. The deepest draft (10 m) within Gradska Luka is obtained at Pier #30. This pier has a length of 135 m.Pier #29 has a draft of 8m, with length 150 m. Pier #28 has a draft of 5.5 m, and a length of 105m. Pier #20's statistics are draft 7.5 m, length 178 m; pier #17 has a 9m draft and a 240 m length;pier #11 has a 5 m depth and a 161 m length and, finally, pier #9 has a 5 m depth and 160 m length.Other locations, on the west side of the port are for very shallow draft vessels. A yacht harbor and marina lies at the southwest corner of the port, immediately west of the port entrance. At the northern port (Bazen Vranjic) piers #1 through #6 are used as docking locations for U. S.Navy vessels. The length of piers #1 through #5, extending through the Ro Ro ramp area is 920 m.Pier #6 has a length of 210 m. A water depth of 10.3 m exists along piers #1 and #2. Depth drops toabout 7.0 m for piers #3, 4, and 5, but increases to 11.3 m for pier #6 on the north side of the harbor.In April 1999, USS THORNE tied up at pier #1. The British utility ship "FORT GRANGE" dockednear pier #4 during late April 1999, providing re-supply services to troops in Bosnia. The quay isvery solidly constructed and is undamaged. Tugs, fenders and other services are available onrequest through port authorities. Harbor As Haven Harbor As Haven The south port (Gradska Luka) is open to the south and a few times a year (late fall, winter, earlyspring) strong southwesterly winds (Lebic) can raise sea height to 1½ - 2 m in port, causing wavesto crash over the north wall of the port. This condition is normally short-lived and over in less than4-5 hours, after which seas abate very rapidly. Much of the harbor is protected from such winds sothat it is possible to move vessels closer to the eastern breakwater (Lukobran) and avoid seriousdamage. The bora can blow very strong in Gradska Luka, with gusts up to 90 kt (46 ms-¹). However, it isnot considered dangerous for ships tied up within the port. Passenger ships, under bora conditions,are tied up closer to the north side of the port, since gusts are strongest at the breakwater to thesouth. The jugo, or scirocco, raises a sea on the west side of Gradska Luka, affecting small boats, whichmust be moved for greater protection to other locations within the port. However, the larger vesselsare secure under the strongest southeasterly winds, at their designated east-side pier locations Gradska Luka has never been forced to close because of weather conditions. Even during the mostsevere wind event it is possible for large vessels to enter or leave the harbor area. Small boating, ofcourse, must be curtailed during such events, both within and outside of the harbor entrance. Bazen Vranjic is well-protected from the force of southerly jugo or scirocco winds. Bora winds, however, are experienced in full intensity. Berths on the north side are protected from thefull force of such winds because of the mountainous peninsula to the north which shields them.The south side berthing locations, however, are unprotected from these winds. Nevertheless,docking locations here, with proper fender protection, are considered safe. It is considered possible for ships to safely enter and tie up in Bazen Vranjic during moderately strong winds, or depart the port area during similarconditions. Winds from the northwest (tramontana) do raise high sea state conditions in BazenVranjic. The occurrence of such winds, however, is rare, and lasts for only a few hours, posing nohazard to vessels tied up with appropriate fender protection. Currents and Tides Currents and Tides A current of about 0.5 kt, moving toward the west, exists in Drvenicki Kanal, the northern approachtoward Split. A strong jugo or scirocco increases the rate, but when these winds cease, a reversal toan easterly moving current is noted. Shifting winds induce current eddies, notable in DrvenickiKanal. The current is weak in Splitski Kanal. A tidal stream moving east or west is sometimes noticeable.Current flow is strongly influenced by prevailing winds. Within Kastelanski Zalev, along the north coast, the normal current observed moves slowlyeastward; this changes to a faster moving westward-directed current under bora, jugo or sciroccoconditions. In Bracki Kanal the normal westerly moving current is strongly influenced by southeasterly jugo orscirocco winds. The current may reach speeds of up to 2.5 kt in the narrow eastern portion of thechannel, slowing to 1.5 kt to the west. A tidal range of about 40-50 cm is observed at Split, which is maximized during winter months. Seiches are unpredictable, but dramatic instances of such phenomena have occurred in the region ofSplit. In September 1977, a meteorologically-induced seiche occurred at Stari Grad, on the island ofHvar, southeast of Split. At this location the water level fell suddenly by more than 2 m, rising againa few minutes later by 2.7 m. Visibility Visibility Visibility is never a problem for ships in the immediate vicinity of Split and neither the north or thesouth port has ever been forced to close because of this factor. Poorer visibility is sometimes experienced, primarily in early morning hours, in the islands off-shore of Split. Fog may be very dense at times, but normally improves rapidly as the morning progresses. Spring Spring Split, as at other locations along the Croatian coast, experiences three violent wind systems that affect ships at transit, at anchor, and within harbor locations. These systems are the bora(northeasterly winds), the southeasterly jugo (or scirocco), and the lebic (southwesterly winds). Statistically, Split experiences the second highest frequency of bora events of any location in Croatia (the first is in Senj, a city to the north). The bora is often analyzed in three strength categories: aweak bora (mean hourly wind speed 11 - 21 kt ); a strong bora (mean hourlywind speed 22 - 34 kt ); and a severe bora (mean hourly wind speed >34 kt (>17ms-¹). Gusts within a bora are commonly twice the sustained wind values. From this it can be seenthat even a weak bora can have gusts of over 40 kt (21 ms-¹) which could pose a significant hazard tosmall boating. Bora onset usually follows frontal passage. Although maximum gusts often occur several hoursafter initial onset, the first strong gust (which may reach hurricane force) comes very suddenly and isimpossible to predict. For this reason great care must be taken before dispensing small boats fromanchorage in Kastelanski Zalev to either the north or south port locations. The bora can be very severeenroute to, and at, both of those locations. The following statistics of bora events at Split are based on data gathered during a 30 year period(1958 - 1987). They show that the greatest frequency of severe bora events at Split occurs fairlyevenly from December through March, while the highest frequency of strong bora events showed apronounced maximum in February. The duration of a severe bora normally was less than 5 hours. However, severe bora conditions havelasted continuously for as long as 25 hours (14 - 15 March 1962). The highest sustained meanhourly wind speed of 58.4 kt (30 ms-¹) was also recorded during that event. Maximum gust speedin a bora at Split was recorded at 90 kt (46 ms-¹) on 31 January 1983. As in Dubrovnik, the Harbor Master and Port Authority at Split place great reliability on local lorewhich indicates that bora winds can be reliably be predicted to occur on 7, 17, and 27 March. If a strong bora is blowing at Dubrovnik there is a high probability (84%) that even stronger boraconditions exist at Split. The jugo or scirocco is a south to southeasterly wind which affects Split during the spring, having a peak frequency in March and November. The jugo is generally not a scirocco, although theterms are often used interchangeably. The term "jugo" is applied to southerly winds that occur inadvance of a low moving across the northern Adriatic. Only when this low expands adequately todraw dry and dusty air from North Africa into the Adriatic does the term "scirocco" really apply. The jugo can be as as dangerous as the bora, and particularly affects anchorages and small boatingsoutheast of Gradska Luka, where winds of 40 - 50 kt (21 -26 ms-¹), and seas raised to 3 - 4 m arenot uncommon. Conditions are somewhat less severe in Kastelanski Zalev, except on the coastalregion on the north side of Ciovo Island where jugo effects are severe. Unlike the bora, the windsand seas during a jugo build gradually, in a predictable fashion, and there is usually adequate time totake defensive measures. The winds of a "severe" jugo having speeds of greater than 34 kt (17 ms-¹) last only about 5 hours, buton exception, can extend to 25 hours. Strong jugos with winds from 21 -34 kt (11 - 17 ms-¹) havean average duration of 19 hours, and with exception to 36 hours. The highest mean hourly windspeed for a jugo in the Adriatic (based on data from 1958-1987), was 53 kt (27 ms-¹). This occurred on 21 March1971. It is often observed at Split, and other locations along the Croatian coast, that there can be a rapidchange from strong southeasterly winds (jugo) to equally strong northeasterly winds (bora) in as littleas one hour. This is a natural consequence of an intense low pressure system moving rapidly southeastward through the region. Similarly, the lebic often follows the jugo in springtime as a violent southwesterly wind. The lebicoccurs as the low pressure center moves on a track across the northern Adriatic north of Split. The changing wind direction from SE to S to SW to W produces choppy and confused seas, dangerousto small boating. Most affected by this is the south port of Split (Gradska Luka) which is open tothe south. Thunderstorms sometimes occur during springtime at Split, as dry, cool air, swinging around alow to the north, encounters a current of warm, moist air, flowing northward over the Adriatic fromthe south. Summer Summer The summer season produces generally fair weather for Split. For weeks at a time weather maybe calm, as on a protected lake. The generally hot and humid conditions are relieved by the northwesterly maestral (mistral) wind which is the dominant wind of summer. The maestral in theAdriatic has been defined as the superposition and enhancement of the etesian (a northerly wind) bythe sea breeze. The maestral is a gentle breeze of 3 - 10 kt (1.5 - 5 ms-¹), normally starting by 1000 or1100 local time and lasting until 1500 or 1600 in the afternoon. Despite the light intensity, a choppysea condition is sometimes produced that can adversely affect small boating. Onshore the maestral is welcomed for some relief of the hot and humid conditions that generally prevail. Maestral winds quickly diminish after sunset, becoming calm during the evening, and byearly morning an offshore northeasterly flow (land breeze) develops, lasting until about 0800 localtime. The jugo is occasionally evident during summer, but the intensity is weak and duration only a few hours so that little problem is posed for boating. Bora events are a rarity during the summer with a frequency of only once or twice every few years.When they do occur the duration is usually less than 5 hours. Autumn Autumn Quiet summer conditions generally prevail through the months of September and October astemperatures begin to moderate. Jugo and bora wind events occur infrequently, most of them lastingless than 5 hours. The lebic also occurs during October, usually following a jugo. The lebic (a southwest wind) always creates problems for small boats attempting to enter the south port (GradskaLuka). In the month of November, Split experiences the second peak frequency (first in March) of severe jugo wind conditions. A severe jugo implies S - SE winds with intensity of greater than 34 kt(17 ms-¹) for at least one hour. Jugo conditions, because of the long fetch, can produce very significant swell, with maximum wave heights exceeding 10 m. Winds and swell are best developedover the open sea and coastal island channels. Anchorage southeast of Gradska Luka in the Bracki Kanal is especially adversely affected, as is the northern coastal region of Ciovo Island in KastelanskiZalev. The north port (Bazen Vranjic) is unaffected by jugo or scirocco conditions. Strong bora wind conditions (20 -34 kt,10 -17 ms-¹ ) are normally experienced a couple of timesduring the month of November, and on rarer occasions the severe bora occurs, with winds in excess of 34 kt (17ms-¹). Winter Winter Easterly to northeasterly winds predominate during the winter season, reflecting a high frequency of bora events. January has the highest annual relative frequency of severe bora winds (mean hourlywind speed >34 kt; 17 ms -¹) and the highest relative frequency of number of hours with the severebora. The strongest bora gust recorded at Split was 90 kt (46ms-¹), registered on 31 January 1983. The longest duration of a strong bora (winds 21-34 kt; 11 - 17 ms-¹) at Split (based on datafrom 1958 - 1987) was 25 hours (14 -15 March 1962). The vast majority of times, however, strongbora duration was less than 5 hours. The jugo or scirocco and lebic also have a high frequency during the winter season, making itinadvisable to attempt small boat entrance to the south port (Gradska Luka) during such conditions(southerly or westerly flow in choppy seas). Under such conditions movement of ships intoKastelanski Zalev for anchorage or into the northern port area of Bazen Vranjic is recommended. Despite the above information concerning high winds it is important to realize that there are winterperiods when high pressure dominates the region, and seas can be essentially calm for periods ofseveral weeks. It is also a statistical fact that the dominant wind speed in the region during winter is 34 kt; 17 ms-¹) is greatest. An alternate potential for ships, who may desire to"ride out" the jugo, is to move to an anchorage position off the west coast of Brac Island, north ofSplitska Vrata, as close to shore as possible. This position offers good protection from even thestrongest jugo wind and wave effect. When bora winds are forecast in Kastelanski Zalev, movement into port at Bazen Vranjic (or Gradska Luka) should be considered. Both the north and south ports of Split are open to theeffects of northeasterly bora winds, but remaining in harbor is recommended, and no instances of damage to ships at harbor during bora events have been reported. When a severe bora (winds >34 kt or 17 ms-¹) occurs while at anchorage , either southeast of Gradska Luka or in Kastelanski Zalev, it is normally best to remain at anchorage since the averageduration of severe conditions is less than 5 hours. However, if holding is poor, and if severe effects are forecast to last for an extended period (severe bora effects at Split have lasted for over 25 hours)an alternate anchorage is recommended along the west coast of Brac Island just south of the northwestern tip of the island. Sortie/Remain in Port Sortie/Remain in Port Both the north and south port at Split are considered safe havens during any of the most adverse weather conditions that affect the region. Pier locations closer to the northeast side of the port in Gradska Luka are less subject to strong bora effects than those at or near the breakwater. In BazenVranjic, pier #6 offers greatest protection from northeast bora winds. This harbor is fully protectedfrom the effects of the southeasterly jugo or scirocco. The Harbor Master and Port Authority advise that neither port has ever been closed with respect to entry or departure for any weather-related condition. Scheduling Scheduling Late spring, summer, and early fall, is the best period to consider anchorage southeast of the southport of Split for small boat entry into the old port (Gradska Luka). Seas are frequently placid duringthis period. The northwesterly maestral winds, prevalent during the summer, are often enhanced bythe sea breeze during the afternoon hours to speeds of 10 kt (5 ms-¹) or higher. For this reason smallboat entry into both the old port (Gradska Lucka) and the commercial/military port (Bazen Vranjic) ismore safely conducted during the early morning hours, with return to anchorage positions near sunsetor later, when calmer conditions normally prevail. Late fall, winter, and early spring, are months when weather problems are more likely to occur. Thejugo or scirocco adversely affects anchorage southeast of Gradska Luka. Movement into a pierlocation within Bazen Vranjic provides complete protection from the effects of the jugo. The bora adversely affects anchorages locations for both the south and north port. Although the averageduration of a bora is less than 5 hours, some events with sustained winds up to 34 kt (17 ms-¹) last forover 24 hours. Under such conditions movement from anchorage to a harbor location may be the bestalternative. Harbor Protection Harbor Protection Wind and Weather: The old port (Gradska Luka) is open to the south and a few times a year (late fall, winter, earlyspring) strong southwesterly winds (lebic) enter the port region. This condition is normallyshort-lived and over in less than 4 -5 hours. Much of the harbor is protected from such windsso that it is possible to move vessels closer to the eastern breakwater (Lukobran) and avoidserious damage. During a strong jugo event southeasterly winds are felt on the west side of theport causing problems for small boats. Bora winds blow violently across the harbor. Berth positions #9 and #11 are somewhat more protected than piers #28-30. Bazen Vranjic is affected only by the bora and offers good protection from southeasterly jugo or scirocco winds. Pier #6 on the north side of the port is better protected against the bora thanpier positions #1 through 5 on the south side Waves: Under strong southwesterly winds, waves of 1 ½- 2 m can move through the entrance toGradska Luka and crash over the north wall of the port. Movement of ships closer to theBreakwater on the east side of the port provides protection from such conditions. Bazen Vranjic is susceptible to wave height increase in port under northwesterly (tramontana)wind conditions. The occurrence of such winds is rare, however, and lasts for only a few hours, posing no threat to vessels tied up and protected with appropriate fenders. Local Hazardous Weather Conditions Local Hazardous Weather Conditions Warning information. Weather forecasts for the Adriatic coast are prepared by the MarineMeteorological Center in Split. These are updated throughout the day and broadcast periodically inCroatian, English, French, German, and Italian. Forecasts in English are broadcast at 0700, 1100, and1800, local time. Reception of such forecasts is generally on VHF channels 4 and 7. If difficulty isencountered, the Harbor Master's office may be contacted on channel 16 for the most recentinformation, and possible channel changes. NAVTEX marine weather forecasts are also available.The Harbor Master's office also receives daily, via facsimile from the Marine Meteorological Centerin Split, a one page summary of weather information, including a synoptic surface chart, valid for0300 local, specific port warnings in effect, a 3-day outlook, and local weather conditions for 14 portsalong the Croatian coast. This report is sent separately to each major port subscribing to the service.24 hour forecasts are considered quite accurate, employing the latest techniques in mesoscalemodeling. The three most severe wind systems affecting the port of Split are the jugo, or scirocco, the bora, and the lebic. The jugo or scirocco adversely affects anchorage locations near the south port (Gradska Luka), and raises sea height somewhat less severely in the western portion of Kastelanski Zalev.The north port (Bazen Vranjic) is well-protected from southeasterly jugo or scirocco effects. Ships atanchor southeast of Gradska Luka can find safe refuge either by moving to a new anchorage alongthe west coast of Brac Island, as close to shore as possible, or by tying up at a pier positionwithin Bazen Vranjic. Ships anchored within Kastelanski Zalev can find similar refuge by movingto either of those locations. The jugo also causes increased sea state in the western portion of the south harbor, creating problems for small boats anchored or moving through that region. The bora causes problems for anchorage locations both in Bracki Kanal and in Kastelanski Zalev.Movement to pier positions in the north or south harbors is recommended. Although both harborsexperience very intense bora wind effects, the pier positions, given proper fender protection, areconsidered safe. No accounts of damage to ships while tied up at these locations have been reported.The bora often funnels through valley regions as a mountain gap wind. The effect on sea state is dramatic. Local fisherman and boat owners watch for signs of a transition to white, foam-covered water ahead, and take appropriate precautionary measures (stopping, coming in closer to shore, etc.).Ships entering from the south through Bracki Kanal should be especially alert to a notorious strongbora region at Uvala Vrulja (43° 21' N, 16° 44' E) where an abrupt depression between two mountain ranges exists. The jugo is commonly terminated and followed by southwesterly winds called lebic. The suddenchange from SE to S to SW, as low pressure, responsible for such winds, moves eastward,produces choppy, confused seas, and is especially dangerous for small boating. Many accidents involving broken arms and legs, while attempting to embark or debark into small boats, haveoccurred under such conditions. The lebic is a special problem for the south port (Gradska Luka)since the port is open to the south. During intense lebic conditions, waves of 1 ½ - 2 m commonlysweep through the port and crash over the walls on the north side of the harbor. Pier positions nearthe breakwater offer complete protection from such effects. Fortunately, the lebic, as a strong wind,normally only occurs only 1 or 2 times a year, and its duration is short, with seas abating rapidly inthe aftermath. Statistics show two peak periods for jugo or scirocco winds, March and November, with very fewoccurrences during the summer. The average duration of the jugo (based on statistics from 1958 - 1987) was about 36 hours; however, severe wind strength (> 34 kt; 17 ms-¹) normally was sustainedfor only 5 hours. The winds are best developed over the open seas and island regions, and havereached a maximum hourly wind speed of 53 kt (27 ms-¹) with a maximum gust of 83 kt (43 ms-¹) at Split. A maximum duration of jugo conditions for 132 hours was registered at Split in1967. Severe speeds (>34 kt; 17 ms-¹) lasted for 25 of those hours. The scirocco, which taps dry, dusty, air from N. Africa, generally occurs in two phases. The firstphase, called "fresh," "new," or "clear," scirocco, is denoted by a gradual strengthening of the wind,and a rise in water level, noticeable at port locations . Skies remain clear during this phase. Local fisherman take these conditions during winter and spring as enough of a sign of deteriorating weatherconditions to return to port. The second phase occurs as winds continue to increase and clouds areobserved, gradually moving over the area from the south. Light to moderate rain often accompaniesthe strong sustained winds of the second phase, leaving a dusty residue over exposed outside objectsin the aftermath. Sea height builds gradually during scirocco conditions, reaching extremes of over 10 m in the open sea regions. During bora conditions sustained winds of 20 - 34 kt (10 - 17 ms-¹) are common. The bora is a noticeably gusty wind; gusts of 40 - 70 kt (21 - 36 ms-¹) are common, and a maximum gust of 90 kt(46 ms-¹) has been recorded at Split. Since the onset of a bora is frequently associated with frontal passage, the period immediately prior is an opportune time to move into a more protected harborposition. The bora has generally been described as a wind of two types; the anticyclonic (also called "white" or"clear") bora, and the cyclonic (also called "dark" or "black") bora. At some locations theysometimes speak of a third type, simply called "bora." The anticyclonic bora or clear bora is the most intense configuration, producing the highest sustained wind speeds, and the highest wind speed gusts. Synoptically, the pattern can be identified as one evolving from an intense high pressure system over eastern Europe, with a low to the south over the Ionian Sea, and the southern Adriatic Sea. A frontal boundary across the northern Adriatic separatesthe two systems, where extremely cold air coming around the east side of the high merges with moist,southerly air, coming around the east side of the low. High pressure tends to change from ameridionally-oriented configuration, to a latitudinally-oriented configuration, as the pressure gradient between the high and the low suddenly intensifies north of the frontal boundary. This produces astrong northeasterly to easterly flow over the Dinaric Alps, north of the front, heading into theAdriatic Sea. Cap clouds are sometimes noted on the mountain crests, giving alert mariners 2-3 hoursof advance warning that strong winds are coming. Knowledge that it is raining on the east side of themountains is often an excellent additional indicator of impending strong bora winds. Data obtainedfrom research aircraft in the region show that winds in the strong pressure gradient region behind thefront actually accelerate upstream of the Alpine mountain ridge before descending as cold"fall"winds onto the coastal regions of the eastern Adriatic. The subsiding motion of the cold dry air along the coast generally clears out all cloudiness in this region - hence, the name "clear" or"white" bora. A key feature for Navy meteorologists and ship captains to understand is that the onsetof strong bora winds normally commences following frontal passage in the strong pressure gradientbehind the front. Equally important is the established fact that highest maximum gusts, oftenappproaching or exceeding hurricane force, usually occur several hours after frontal passage andinitial bora onset. The cyclonic bora, often called the "black" or "dark" bora, is often an evolution of the anticyclonicbora, as high pressure to the north begins to weaken and the frontal boundary moves southwardtoward Greece. The residual low continues to spin warm, moist air over countries bordering theeastern Adriatic, producing low and mid-level cloudiness with rain over the coastal regions (hencethe term "dark" or "black" bora). At the same time the cyclonic motion taps cold air from highpressure to the north, forcing this air over the mountain ridges and into the valleys, producingstrong, 22 - 34 kt (11 - 17 ms-¹) bora winds, at coastal locations. Gusts within the cyclonic bora are often much greater than the sustained wind speed, making them of obvious concern to Naval operations. Both the anticyclonic bora and the cyclonic bora result from pressure patterns obvious in synopticanalyses and forecasts. With present day mesoscale analysis, weather centers, including that at Split,in Croatia, have had great success in predicting these events. They are less successful, however, inpredicting the normal bora, the final type of bora, which frequently catches weather centers, as well asships and small boats off-guard. This is probably the result of an inadequate number of observing stations, having vertical sounding capabilities, in the region. This type of bora, similar to theanticyclonic and cyclonic bora, depends on high pressure and extremely cold air to the east. This coldair, normally, is capped by an inversion, whose height is lower than that of ridgelines of the DinaricAlps, so that the cold air can not reach coastal locations. When this inversion is lifted, for whateverreason, the north-south pressure gradient may be strong enough to force cold air over the ridgelines sothat it can spill down toward the coastal area, gathering speed in the process. Cap cloud formationalong the ridge line of the mountains is taken as an important harbinger that strong bora winds mayoccur within 2 - 3 hours over the coastal regions. Thunderstorms may occur, infrequently, anytime during late fall, winter or spring. They are a usualresult of low pressure moving across the northern Adriatic, bringing cold air around the southerncircumference, converging with a current of warm, moist air, coming up from the Ionian Sea. A necessary corollary condition is that higher level divergence be present over the lower levelconvergent area (normally the divergent area in advance of an upper level trough). Strong gusty windspeeds, especially dangerous to small boats can occur under such conditions. Waterspouts have infrequently been observed in the Split area, with mammatus cloud conditions signalingextreme instability aloft. Wind Chill Table Heat Index Table Split is located on the eastern Adriatic coast about 90 nm northwest of Dubrovnik, Croatia. Port of Split (Croatia) - Port Information