[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE APR 19 2016

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...ITCZ/MONSOON TROUGH...
A WEAK N ILL-DEFINED TROUGH IS ANALYZED ACROSS WESTERN AFRICA TO
THE COAST OF THE BORDER BETWEEN SIERRA LEONE AND LIBERIA WHERE
IT TRANSITIONS TO THE ITCZ OVER THE TROPICAL EASTERN ATLC SW TO
03N18W TO 03N25W TO 02N31W TO 02N44W TO S OF THE EQUATOR NEAR
50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION ALONG AND S
OF THE ITCZ BETWEEN 41W-50W. SCATTERED MODERATE CONVECTION IS
WITHIN 120 NM N OF ITCZ BETWEEN 45W-49W...AND WITHIN 60 NM N
OF ITCZ BETWEEN 25W-28W.
...DISCUSSION...

GULF OF MEXICO...
AN UPPER SHORTWAVE TROUGH IS MOVING E OVER EASTERN TEXAS.
IT SUPPORTS A SURFACE TROUGH ALONG IMMEDIATE TEXAS COAST FROM
GALVESTON TO JUST NE OF BROWNSVILLE THE EARLIER WEAK 1017 MB LOW
NEAR 27N93W HAS WEAKENED TO A TROUGH FROM 29N92W TO 27N94W.
SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND WEAKENING ISOLATED
TSTMS FROM 23N-28N BETWEEN 91W-96W. A SECOND SHORTWAVE UPPER
TROUGH IS JUST INLAND NE MEXICO. THE DIFFLUENT FLOW PATTERN
ALOFT TO ITS E IS PRODUCING LARGE CLUSTERS OF SCATTERED TSTMS
WITH FREQUENT LIGHTNING AND POSSIBLE GUSTY WINDS CONFINED TO THE
SW GULF S OF 23N BETWEEN 91W-93W. THE DIURNAL SURFACE TROUGH HAS
MOVED W DURING THE MORNING...AND EXTENDS FROM NEAR 24N96W TO
19N95W. THIS FEATURE IS ALSO AIDING IN THE AFOREMENTIONED
SCATTERED TSTM ACTIVITY. A SURFACE RIDGE REMAINS OVER THE
EASTERN GULF AND WESTERN ATLC ANCHORED BY A 1024 MB HIGH OVER
SOUTHERN GEORGIA. THE HIGH IN COMBINATION WITH DRY SINKING AIR ALOFT
TO THE E OF THE WESTERN GULF CONVECTIVE ACTIVITY IS MAINTAINING GENERALLY
CLEAR SKIES OVER THE EASTERN GULF. THE SURFACE RIDGE WILL PERSIST
THROUGH THU...THEN SLIDE EASTWARD FRI AS A WEAK COLD FRONT ENTERS
THE NW GULF.

CARIBBEAN SEA...
NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE CARIBBEAN THIS
MORNING. AN UPPER TROUGH OVER THE WESTERN ATLC COMBINED WITH AN UPPER
RIDGE OVER S AMERICA/W TROPICAL ATLC IS GENERATING A JET
STREAK OVER THE NE CARIBBEAN INTO THE CENTRAL ATLC. A COLD FRONT
OVER THE CENTRAL ATLC EXTENDS A DISSIPATING STATIONARY FRONT SW TO
THE LEEWARD/VIRGIN ISLANDS AREA. THE COMBINATION OF SURFACE TO LOW-LEVEL
CONVERGENCE ALONG THE FRONT WITH JET DYNAMICS OVER THE NE CARIBBEAN
IS SETTING OFF SCATTERED TO NUMEROUS SHOWERS AND ISOLATED TSTMS
OVER MUCH OF THE NE CARIBBEAN INCLUDING THE LEEWARD ISLANDS...AND
IMMEDIATE SURROUNDING WATERS. SCATTERED SHOWERS AND TSTMS HAVE
DEVELOPED OVER PUERTO RICO AS DAYTIME HEATING HAS PLAYED A ROLE
IN THE DEVELOPMENT OF THIS ACTIVITY. MAINLY MID TO HIGH CLOUDS ARE
OVER THE SE CARIBBEAN WITH ONLY ISOLATED SHOWERS AND WEAK ISOLATED TSTMS
NOTED THERE. SCATTERED SHOWERS AND ISOLATED TSTMS ARE SEEN TO
THE SSW OF PUERTO RICO WITHIN 60 NM OF A LINE FROM 16N65W TO
16N71W. THE SURFACE RIDGE OVER THE EASTERN GULF OF MEXICO AND
THE WESTERN ATLC EXETNDS TO THE FAR NW CARIBBEAN. THIS IS
LEAVING THE REMAINDER OF THE CARIBBEAN WITH GENERALLY FAIR
WEATHER CONDITIONS THIS AFTERNOON. MODERATE TO FRESH TRADE
WINDS WILL PERSIST ACROSS THE BASIN THROUGH THU NIGHT. NE WINDS
ARE EXPECTED TO PULSE FRESH TO STRONG EACH NIGHT S OF HISPANIOLA
AND ON THE APPROACH TO THE WINDWARD PASSAGE THROUGH THU NIGHT.

HISPANIOLA...
THE SOUTHERN PORTION OF THE CENTRAL ATLC COLD FRONT EXTENDS SW AS
A DISSIPATING STATIONARY FRONT TO THE VIRGIN/LEEWARD ISLANDS AREA.
LOW-LEVEL MOISTURE SPINNING OFF THE FRONTAL BOUNDARY IS BEING ADVECTING
WESTWARD IN THE TRADE WIND FLOW TO THE S OF HISPANIOLA. ISOLATED SHOWERS
ARE POSSIBE NEAR THE SOUTHERN COAST OF HISPANIOLA THROUGH THU.
SATELLITE IMAGERY IS SHOWING SCATTERED TO BROKEN LOW CLOUDS
DEVELOPING INTO HIGH TOP CLOUDS. WITH DAYTIME HEATING
UNDERWAY...SOME OF THESE CLOUDS ARE LIKELY TO TRANSFORM INTO
SHOWERS AND TSTMS DURING THE REST OF THE AFTERNOON.

ATLANTIC OCEAN...
A SURFACE RIDGE COVERS THE W ATLC W OF ABOUT 68W TO THE NW
CARIBBEAN...AND TO OVER THE E GULF OF MEXICO ANCHORED BY A 1024
MB HIGH OVER S GEORGIA. A BROAD UPPER TROUGH COVERS THE WESTERN
AND CENTRAL ATLC WITH A MEAN TROUGH AXIS EXTENDING ROUGHLY FROM
32N54W SW TO 23N66W TO NEAR 23N77W. IT IS SUPPORTING A COLD
FRONT THAT EXTENDS FROM A TRIPLE POINT N OF THE AREA THROUGH
32N44W... AND SW TO 25N50W TO 21N58W WHERE IT BECOMES A
DISSIPATING STATIOANRY FRONT TO THE LEEWARD ISLANDS. A RE-
ENFORCING SURGE IN THE FORM OF A SURFACE TROUGH TRAILS THE FRONT
EXTENDING FROM A 1003 MB LOW NEAR 33N57W SW TO 28N60W TO 25N64W.
UPPER DIFFLUENT ALOFT E OF THE UPPER TROUGH CONTINUES TO
GENERATE SCATTERED TO NUMEROUS SHOWERS/ISOLATED TSTMS WITHIN
150-180 NM OF A LINE FROM THE LEEWARD/VIRGIN ISLANDS NEAR 18N62W
ALONG 23N52W TO 32N41W. A WEAK SURFACE RIDGE COVERS THE
REMAINDER OF THE ATLC ANCHORED BY A 1021 MB HIGH NW OF THE
AZORES AND ANOTHER 1021 MB HIGH NEAR 29N30W. THE CENTRAL ATLC
COLD FRONT WILL MOVE SLOWLY EASTWARD THROUGH WED WHILE
TRANSITIONING INTO A SURFACE TROUGH. ANOTHER COLD FRONT WILL
QUICKLY SWEEP ACROSS THE NE WATERS ON WED. SURFACE RIDGING IS
FORECAST TO BUILD SEWD ACROSS THE W ATLC IN THE WAKE OF THE FRONTS
AND WEAKEN THU NIGHT THROUGH FRI NIGHT.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
AGUIRRE
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