[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040555
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT MAY 04 2013

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 10N14W THEN ALONG 7N16W TO 5N19W WHERE THE ITCZ BEGINS
AND CONTINUES ALONG 3N28W 1N35W THEN S OF THE EQUATOR NEAR 39W.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 5N TO
JUST S OF THE EQUATOR E OF 2W ACROSS THE PRIME MERIDIAN AND
FROM 3N TO THE EQUATOR BETWEEN 2W-10W. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 90 NM EITHER SIDE
OF THE ITCZ BETWEEN 19W-34W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH EXTENDS FROM THE CENTRAL PLAIN STATES TO OVER
THE LOWER MISSISSIPPI VALLEY INTO THE N GULF OF MEXICO N OF 26N
SUPPORTING A WEAK COLD FRONT THAT AT 04/0300 UTC ENTERS THE GULF
OVER PENSACOLA FLORIDA THEN ALONG 27N88W TO N OF THE YUCATAN
PENINSULA NEAR 22N89W. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE N OF 28N BETWEEN 85W-87W WITH POSSIBLE
ISOLATED SHOWERS WITHIN 75/90 NM W OF THE FRONT. NEAR ZONAL
WESTERLY FLOW ALOFT COVERS THE REMAINDER OF THE GULF. WATER
VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSTANCE WITH DRY STABLE
AIR ALOFT OVER MOST OF THE GULF LIMITING SHOWER ACTIVITY
ASSOCIATED WITH THE ABOVE FRONT. A WEAK SURFACE RIDGE COVERS THE
W GULF ANCHORED BY A 1024 MB HIGH ALONG THE COAST OF MEXICO NEAR
TUXPAN. THIS SURFACE FLOW IS BANKING LOW LEVEL CLOUDS WITH
POSSIBLE ISOLATED SHOWERS OVER THE SW GULF S OF 23N W OF 92W.
THE FRONT WILL CONTINUE TO MOVE EASTWARD TONIGHT AND SAT WHILE
WEAKENING. ANOTHER COLD FRONT IS EXPECTED TO SWEEP ACROSS THE NE
GULF LATE SAT THROUGH SUN. WINDS AND SEAS WILL DIMINISH OVER
MUCH OF THE AREA MON THROUGH WED AS WEAK HIGH PRES SETTLES OVER
THE GULF WATERS.

CARIBBEAN SEA...
A BROAD UPPER RIDGE ANCHORED IN THE TROPICAL ATLC NEAR 7N44W
EXTENDS A RIDGE AXIS INTO THE CARIBBEAN OVER TRINIDAD ALONG THE
N COAST OF SOUTH AMERICA TO OVER CENTRAL AMERICA NEAR 13N84W.
THIS IS GIVING MOST OF THE CARIBBEAN WESTERLY FLOW ALOFT WITH
BROKEN TO OVERCAST HIGH CLOUDS SE OF A LINE FROM THE MONA
PASSAGE ALONG 17N77W TO NICARAGUA NEAR 14N84W. A SURFACE TROUGH
EXTENDS FROM THE W ATLC ACROSS CUBA NEAR 22N79W THROUGH THE
CAYMAN ISLANDS TO 17N82W WITH ISOLATED SHOWERS WITHIN 60 NM E OF
THE TROUGH. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE N OF 16N TO OVER HAITI...E CUBA...AND THE
WINDWARD PASSAGE BETWEEN 73W-78W INCLUDING JAMAICA. THE MONSOON
TROUGH EXTENDS ACROSS PANAMA AND COSTA RICA GENERATING SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 10N-13N W OF
81W TO INLAND OVER COSTA RICA AND NICARAGUA. THIS IS LEAVING THE
REMAINDER OF THE NW CARIBBEAN CLEAR TONIGHT WITH SOME ISOLATED
SHOWERS INLAND AND WITHIN 60 NM ALONG THE COAST OF BELIZE. FRESH
TO STRONG NORTHERLY WINDS FOLLOW THE SURFACE TROUGH AND ARE
FORECAST TO SHIFT E TO 78W BY SAT. UNUSUALLY MILD WIND FLOW AND
SLIGHT SEAS WILL DOMINATE THE REMAINDER OF CARIBBEAN SEA.

ATLANTIC OCEAN...
A SHORTWAVE UPPER TROUGH EXTENDS FROM SE GEORGIA TO OFF THE
FLORIDA COAST NEAR 26N78W SUPPORTING A 1004 MB SURFACE LOW THAT
AT 04/0300 UTC IS CENTERED INLAND OVER FLORIDA NEAR 28N81W WITH
A SURFACE TROUGH EXTENDING INTO THE W ATLC ALONG 26N79W ALONG
24N79W CROSSING CUBA INTO THE CARIBBEAN NEAR 22N79W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 26N-30N W OF 78W TO THE
FLORIDA COAST/SURFACE TROUGH. THIS SHORTWAVE UPPER TROUGH IS
AMPLIFYING AN UPPER RIDGE THAT EXTENDS FROM E OF THE BAHAMAS
NEAR 26N72W N-NW TO BEYOND 32N76W. A WEAK STATIONARY FRONT
EXTENDS FROM THE SURFACE LOW ALONG 26N75W 23N66W TO 23N60W. THIS
UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90 NM S AND
200 NM N OF THE FRONT W OF 67W. NEAR ZONAL WESTERLY FLOW ALOFT
DOMINATES THE REMAINDER OF THE ATLC BASIN. AN UPPER TROUGH N OF
THE DISCUSSION AREA IS SUPPORTING A SURFACE TROUGH THAT ENTERS
THE CENTRAL ATLC THROUGH 32N45W ALONG 25N49W TO 23N59W. DENSE
CLOUD COVER WITH POSSIBLE SHOWERS COVERS THE ATLC FROM 20N-30N
BETWEEN 35W-67W. A SURFACE RIDGE COVERS THE E ATLC ANCHORED BY A
1022 MB HIGH NEAR 31N19W AND A 1023 MB HIGH OFF THE COAST OF
PORTUGAL. THE SURFACE LOW OVER FLORIDA IS FORECAST TO MOVE
SLOWLY TOWARD N FLORIDA SAT AND ACROSS SE GEORGIA SUN. A SURFACE
TROUGH WILL MOVE IN TANDEM WITH THE LOW EXTENDING JUST E OF THE
BAHAMAS SAT AND FROM 32N80W TO ABOUT 25N73W SUN AND NE OF THE
AREA BY MON.

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

AT THE REQUEST OF METEO-FRANCE AND THE METEROLOGICAL SERVICES OF
HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND
FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY
BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL
WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE
DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES
ON THE ISLAND OF HISPANIOLA.

THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT
WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE
EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS
ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL.

$$
PAW

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