[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 14 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
A GALE WARNING WILL BE IN EFFECT FOR THE GULF OF MEXICO
BEGINNING 15/0600 UTC FOR NORTHERLY WINDS OF 35 KT IN
ASSOCIATION WITH A COLD FRONT CURRENTLY ANALYZED ACROSS THE NW
GULF WATERS. THE WINDS IN WAKE OF THE COLD FRONT ARE CURRENTLY
IN THE RANGE OF 20 TO 30 KT BEFORE INCREASING LATER TONIGHT. SEE
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
09N13W TO 07N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 07N17W THROUGH 05N130W TO THE EQUATOR NEAR 45W.
SCATTERED MODERATE CONVECTION IS FROM 03N TO 07N FROM THE COAST
OF AFRICA TO 23W...AND FROM 03N TO 05N BETWEEN 30W AND 37W.

...DISCUSSION...

GULF OF MEXICO...
MID TO UPPER LEVEL WEST-SOUTHWESTERLY FLOW IS NOTED ON WATER
VAPOR IMAGERY OVER THE GULF WITH MOST MID TO UPPER LEVEL
MOISTURE REMAINING NORTH OF 25N. THIS MOISTURE CONTINUES TO
ADVECT NORTHEASTWARD AHEAD OF AN APPROACHING MID TO UPPER LEVEL
SHORTWAVE TROUGH MOVING OVER EASTERN TEXAS AND THE MISSISSIPPI
RIVER VALLEY. UPPER LEVEL SATELLITE DERIVED WINDS WERE ON THE
ORDER OF 90-110 KT ALONG THE IMMEDIATE GULF COAST. AT THE
SURFACE...A COLD FRONT EXTENDS FROM THE SOUTH-CENTRAL LOUISIANA
COAST NEAR HOUMA SW TO THE EXTREME NORTHEAST COAST OF MEXICO
NEAR 25N98W. LOW LEVEL MOISTURE CONVERGENCE ALONG WITH THE
FAVORABLE MIDDLE TO UPPER LEVEL DYNAMICS ARE GENERATING
SCATTERED SHOWERS AND TSTMS EAST OF THE COLD FRONT WITHIN 20-40
NM EITHER SIDE OF A LINE FROM THE BIG BEND OF FLORIDA TO 27N90W.
SCATTERED SHOWERS ARE ALSO OCCURRING WITHIN 120-180 NM NW OF THE
FRONT GENERALLY ACROSS THE NW GULF EXTENDING NE ACROSS COASTAL
LOUISIANA AND MISSISSIPPI AND SOUTHERN ALABAMA. AS THE COLD
FRONT PUSHES EASTWARD OVERNIGHT AND INTO THE SW NORTH ATLC BY
LATE SUNDAY INTO EARLY MONDAY...STRONG NORTHERLY WINDS ARE
FORECAST TO SPREAD EASTWARD IN WAKE OF THE FRONT ACROSS THE
ENTIRE BASIN. DURING THE NEXT 24 HOURS THE STRONGEST WINDS...OF
GALE FORCE...ARE MOST LIKELY TO OCCUR ACROSS THE WESTERN GULF
INITIALLY WITH THE AREA MIGRATING SOUTHWARD INTO THE SW GULF
LATE SUNDAY MORNING INTO SUNDAY AFTERNOON. THEREAFTER...THE
EXISTING PRESSURE GRADIENT WILL RELAX SOMEWHAT AS HIGH PRESSURE
BUILDS IN ACROSS THE COASTAL GULF PLAINS WITH NE WINDS IN THE
RANGE OF 10 TO 20 KT PERSISTING INTO EARLY NEXT WEEK.

CARIBBEAN SEA...
MID TO UPPER LEVEL NORTHWESTERLY TO WESTERLY FLOW DOMINATES THE
CARIBBEAN THIS EVENING WITH WATER VAPOR IMAGERY INDICATING A
VERY DRY AND STABLE AIRMASS PROVIDING OVERALL TRANQUIL
CONDITIONS AT THE SURFACE. THE ONLY FEATURE OF NOTE IS THE CLOSE
PROXIMITY OF THE MONSOON TROUGH AXIS ANALYZED FROM NORTHERN
COLOMBIA ACROSS PANAMA AND SOUTHERN COSTA RICA INTO THE EAST
PACIFIC OCEAN. SCATTERED SHOWERS AND TSTMS ARE OCCURRING S OF
11N IN ASSOCIATION WITH THIS FEATURE. OTHERWISE...PASSING LOW-
TOPPED ISOLATED SHOWERS ARE POSSIBLE BASIN-WIDE WITHIN STRONG
TRADE WIND FLOW IN THE RANGE OF 20 TO 30 KT THROUGH EARLY NEXT
WEEK.

...HISPANIOLA...
CURRENTLY DRY NORTHWESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR
IMAGERY OVER HISPANIOLA PROVIDING FOR OVERALL DRY AND STABLE
CONDITIONS. AT THE SURFACE...EAST-SOUTHEAST WINDS PREVAIL AND
ARE EXPECTED TO PERSIST INTO EARLY NEXT WEEK. EMBEDDED WITHIN
THE TRADE WIND FLOW...PASSING LOW-TOPPED ISOLATED SHOWERS WILL
REMAIN A POSSIBILITY THROUGH EARLY NEXT WEEK. OTHERWISE...
CONTINUED FAIR WEATHER IS EXPECTED.

ATLANTIC OCEAN...
A BROAD UPPER LEVEL TROUGH IS NOTED OVER THE CENTRAL ATLC
EXTENDING FROM 32N57W SOUTHWESTWARD TO THE MONA PASSAGE BETWEEN
HISPANIOLA AND PUERTO RICO. THIS TROUGHING ALOFT SUPPORTS A
STATIONARY FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N43W
THAT MEANDERS SW TO 27N56W AND GRADUALLY DISSIPATES TO 24N65W.
ISOLATED LOW TOPPED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER
SIDE OF THE FRONT. TO THE WEST ACROSS THE SW NORTH ATLC...EAST-
SOUTHEASTERLY FLOW PERSISTS GENERALLY IN THE RANGE OF 10 TO 20
KT...INCREASING TO 20-25 KT OVER THE FAR NW PORTION OF THE
DISCUSSION AREA IN ADVANCE OF A COLD FRONT OVER THE SE CONUS.
LOW-LEVEL MOISTURE IS INCREASING N OF 27N W OF 70W...AND
SCATTERED SHOWERS AND ISOLATED TSTMS WERE ORGANIZING OVER THE
FAR NW PORTION OF THE AREA N OF 29N W OF 79W. A 1028 MB HIGH WAS
CENTERED NEAR BERMUDA AND A 1029 MB HIGH WAS NEAR 31N58W.
FINALLY...ANOTHER SURFACE RIDGE INFLUENCED THE FAR EASTERN ATLC
ANCHORED BY A 1030 MB HIGH CENTERED SOUTH OF THE AZORES NEAR
32N29W. MUCH EARLIER SCATTEROMETER PASSES SHOWED A LARGE AREA OF
NE TO E WINDS IN THE RANGE OF 20 TO 30 KT...WITH THE STRONG
WINDS OCCURRING WITHIN 300 NM EITHER SIDE OF A LINE FROM 20N24W
TO 12N55W.

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

$$
COBB

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