000 AXNT20 KNHC 142357 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 757 PM EDT Fri Apr 14 2017 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURE... The 30-hour forecast consists of a low pressure center that will be to the NE of the area. A cold front will extend from 31N50W to 22N52W to 18N67W. Expect NW gale-force winds and sea heights ranging from 11 feet to 13 feet, to the N OF 30N between 52W and 56W. Please refer to the high seas forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...MONSOON TROUGH/ITCZ... The Monsoon Trough passes through the coastal sections of Sierra Leone near 07N13W, to 03N17W. The ITCZ continues from 03N17W, to the Equator along 26W, to the coast of Brazil near 03S42W. Convective precipitation: isolated moderate to locally strong within 360 nm to 480 nm to the SE of the line that runs from 06N11W to 05N22W to 04N40W and 06N53W. ...DISCUSSION... ...THE GULF OF MEXICO... A middle level to upper level trough passes through East Texas to the Yucatan Peninsula. Middle level to upper level anticyclonic wind flow with a ridge covers the eastern half of the Gulf of Mexico. Convective precipitation: widely scattered moderate to isolated strong from 23N to the coast between 85W and 92W. A surface trough is in the SW corner of the Gulf of Mexico, along 93W, from 22N southward. Broad surface anticyclonic wind flow spans the Gulf of Mexico. ...LOW LEVEL CLOUD CEILINGS AND WEATHER FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N NORTHWARD AND FROM 88W WESTWARD... LIFR: none. IFR: none. MVFR: KEIR and KVOA. LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA... from TEXAS to FLORIDA: VFR. ...THE CARIBBEAN SEA... Upper level SW wind flow covers the area that is to the east of the line that runs from the central coast of Honduras beyond SE Cuba. Middle level to upper level westerly wind flow covers the rest of the Caribbean Sea. Rainshowers are possible, in the Caribbean Sea, in scattered to broken low level clouds, from the coast of Haiti near 18N72W to the coast of Panama near 09N78W, and to the W and SW of the line 20N85W 09N80W. 24-hour rainfall totals that are listed for the period that ended at 14/1200 UTC...according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...0.02 in Guadeloupe, 0.01 in San Juan in Puerto Rico, and a trace in Trinidad. ...HISPANIOLA... Upper level SW wind flow is crossing Hispaniola. SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the DOMINICAN REPUBLIC: Barahona: VFR. Santo Domingo: VFR. La Romana: VFR. Punta Cana: VFR. Santiago: VFR. Puerto Plata: VFR. The GFS MODEL forecast for 250 mb shows that broad SW wind flow will cover the area for the entire time. The GFS MODEL forecast for 500 mb shows that generally W-to-SW wind flow will be moving across the area during the next 48 hours. Hispaniola will be on the southern side of an Atlantic Ocean trough/area of cyclonic wind flow. The GFS MODEL forecast for 700 mb shows that the Hispaniola will be in the middle of a ridge to the SE and to the NW, and a trough to the NE and an inverted trough to the SW, for the first 24 hours. The ridge that is to the SE will move across Hispaniola during day two, spreading anticyclonic wind flow across the area. ...THE ATLANTIC OCEAN... An upper level trough passes through 32N63W to 25N65W and 20N70W. A 1012 low pressure center is near 24N67W. A surface trough extends from the 1012 mb low pressure center, to 22N66W and 20N72W. An occluded front curves away from the low center, to 25N70W to 28N65W. A stationary front continues from 28N65W to 25N53W. A surface trough continues from 28N65W to 24N62W, and 18N64W. Convective precipitation: widely scattered moderate to isolated strong from 24N northward between 55W and 65W. Rainshowers are possible from 20N northward from 43W westward to the SE coast of the U.S.A. A middle level to upper level trough passes through 32N33W to 25N37W and 19N38W. A cold front passes through 32N26W, to 28N30W, and 22N35W. Convective precipitation: scattered moderate within 60 nm on either side of the line that passes through 32N27W to 30N28W. Rainshowers are possible within 60 nm on either side of 30N28W 26N32W 21N37W. For additional information please visit http://www.hurricanes.gov/marine $$ MT ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across the western Africa coast near 06N11W to 02N18W. The Intertropical Convergence Zone continues from 02N18W to 01S30W to 03S41W. Scattered moderate to strong convection is S of the Monsoon Trough from 00N-06N between 00W- 06W. Scattered moderate convection is along the ITCZ from 02S-03N between 18W-27W, and from 01N-04N between 29W-35W. Widely scattered moderate convection is from 03S-02N between 38W-44W. ...DISCUSSION... ...THE GULF OF MEXICO... Broad surface ridging is over the Gulf of Mexico with 10-15 kt easterly flow. An embedded surface trough is over the SE Gulf of Mexico from 26N87W to 22N87W. Scattered moderate convection is within 60 nm of the trough moving W. Elsewhere, scattered showers are along the coast of Louisiana. In the upper levels, a small trough is over the W Gulf of Mexico with axis along 93W. Upper level diffluence E of the trough is enhancing the convection over the SE Gulf. Expect over the next 24 hours for convection over the SE Gulf to move to the central Gulf. CARIBBEAN SEA... 15-20 kt tradewinds are over the Caribbean Sea with the weakest winds over the Leeward Islands, and the strongest winds along the coast of Colombia. A tail end of a surface trough reaches the Leeward Islands near 18N64W. Another surface trough is just N of Hispaniola. Scattered moderate convection is inland over N Colombia and Venezuela. Elsewhere, scattered showers are over W Panama, Costa Rica, E Nicaragua, Honduras, and S Guatemala. In the upper levels, a broad ridge is over the Caribbean Sea. Upper level moisture is over N Colombia and Venezuela. Strong subsidence is over the NW Caribbean. Expect over the next 24 hours for the eastern and central Caribbean to have additional scattered showers. ...HISPANIOLA... After a dry start today, expect low level moisture and showers to increase as a trough reaches the northern portion of Hispaniola by this afternoon. Winds will increase out of the northeast later on Saturday as strong high pressure builds north of the area. ATLANTIC OCEAN... Low pressure of 1012 mb resides near 25N68W with a surface trough that extends from the low to 23N66W to S of the Turks and Caicos near 21N73W. A stationary front extends from 24N52W to 27N60W, then transitions to an occluded front from 28N65W to 25N70W. Another surface trough extends south front the triple point of the fronts near 28N65W to 24N62W to 18N64W. Scattered showers and thunderstorms are N of 24N between 50W-67W. Fresh to strong east to northeast winds are occurring north of the occluded front. A cold front enters the area of discussion near 31N28W and extends to 22N36W. Scattered showers are within 60 nm of the front. High pressure centered near 36N13W covers the remainder of the eastern Atlantic. Over the next 24 hours new low pressure will develop to the northeast of the current low, and the current low will become absorbed by the new low as the entire system will move northeast over the central Atlantic early this weekend. Scattered to numerous showers and thunderstorms will accompany this broad system. On Saturday evening, gale force winds will develop behind a cold front that will extend southwest from the low. Please refer to the special features section for more details. For additional information please visit http://www.hurricanes.gov/marine $$ MT