[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAY 12 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL
ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 53W/54W S OF 10N MOVING W 10-15 KT. THE
WAVE COUPLED WITH THE ITCZ IS ENHANCING CONVECTION OVER THE
GUYANAS REGION. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
IS FROM EQUATOR TO 7N BETWEEN 51W AND 58W. AN EARLIER QUIKSCAT
PASS SHOWED LOW-LEVEL NE FLOW OF 15 TO 20 KT ACROSS THIS AREA.
THE GFS MODEL HAS MOISTURE FROM THIS TROPICAL WAVE SPREADING
OVER THE SOUTHERN WINDWARD ISLANDS ON WED.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N12W 2N25W 3N45W 4N51W. A CLUSTER
OF MODERATE TO STRONG CONVECTION IS NEAR 4N15W. SCATTERED
MODERATE CONVECTION IS WITHIN 300 NM N OF AXIS BETWEEN 39W AND
45W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG EXTRATROPICAL CYCLONE IS JUST OFFSHORE THE MID-ATLANTIC
STATES MOVING SE ACROSS THE OCEAN. AS OF 2100 UTC...THE
ASSOCIATED COLD FRONT ENTERS THE FORECAST AREA NEAR 31N73W THEN
CONTINUES SW ACROSS SOUTH FLORIDA AND THE EASTERN GULF TO NEAR
25N87W. AT THIS POINT...THE FRONT BECOMES STATIONARY AND EXTENDS
ALONG 26N90W 27N97W. UNUSUAL MODERATE TO STRONG WLY WINDS WERE
BLOWING AHEAD OF THE FRONT OVER SOUTH FLORIDA DURING THE WEEKEND
BUT PARTICULARLY ON SUN...ALLOWING TEMPERATURES TO CLIMB INTO
THE MID 90S. LATEST VIS IMAGERY FOR THE DAY SHOW A VERY WELL
DEFINED ROPE CLOUD LINE AND EMBEDDED ISOLATED SHOWERS ASSOCIATED
WITH THE FRONTAL BOUNDARY. HIGH PRES WITH A COOLER AND MUCH
DRIER AIR MASS IS BUILDING INTO THE AREA BEHIND THE FRONT. NLY
WINDS OF 15-20 KT FOLLOW THE FRONTAL SYSTEM IN THE E PORTION OF
THE GULF. THIS FRONT IS EXPECTED TO REACH WEST-CENTRAL CUBA LATE
TUE MORNING. ALOFT...A MID/UPPER RIDGE ANCHORED ON A HIGH OVER
THE GULF OF HONDURAS DOMINATES THE ENTIRE GULF REGION. SWLY
UPPER LEVEL WINDS ON THE WESTERN SIDE OF THE RIDGE ARE ENHANCING
CONVECTION ACROSS NORTH-CENTRAL MEXICO.

CARIBBEAN SEA...
A MID TO UPPER HIGH CENTERED OVER THE GULF OF HONDURAS EXTENDS A
RIDGE OVER THE WEST AND CENTRAL CARIBBEAN WHILE UPPER TROUGHING
RUNS FROM THE NRN LEEWARD ISLANDS TO THE N COAST OF COLOMBIA.
MODERATE TO STRONG SUBSIDENCE AND IMPLIED DRY/STABLE AIR MASS IS
WITHIN THE RIDGE SUPPRESSING THE DEVELOPMENT OF ANY SIGNIFICANT
CONVECTION. AT THE SURFACE...HIGH PRES OVER THE EASTERN ATLANTIC
NEAR 29N31W EXTENDS A RIDGE TO THE EASTERN CARIBBEAN INCLUDING
PUERTO RICO AND THE VIRGIN ISLANDS. THIS RIDGE IS GIVING THE
AREA MOSTLY FAIR WEATHER AND A PREVAILING SOUTHEAST WIND FLOW.
MODERATE TRADE WINDS OF 15 TO 20 KT ARE FOUND OVER THE CENTRAL
CARIBBEAN MAINLY JUST OFFSHORE THE COLOMBIAN COAST WITH LIGHT TO
MODERATE E TO SE WINDS ELSEWHERE. ACCORDING TO THE COMPUTER
MODEL...THE TROPICAL WAVE CURRENTLY ALONG 53W/54W WILL PROBABLY
BRING SOME MOISTURE TO THE SRN WINDWARD ISLANDS ON WED.

ATLANTIC OCEAN...
THE LARGE EXTRATROPICAL CYCLONE THAT HAS BEEN PRODUCING COLD AND
RAINY CONDITIONS AS WELL AS STRONG WINDS OVER THE NE OF U.S. AND
THE MID ATLC STATE IS FINALLY MOVING AWAY FROM THE AREA. AS A
RESULT...COASTAL WINDS ARE FORECAST TO STEADILY DIMINISH TONIGHT
THROUGH TUE. THE ATTENDANT COLD FRONT ENTERS THE FORECAST AREA
NEAR 31N73W THEN CONTINUES SW ACROSS SOUTH FLORIDA AND THE
EASTERN GULF. A BAND OF SHOWERS AND ISOLATED TSTMS IS AHEAD OF
THE FRONT AFFECTING THE AREA N OF 27N BETWEEN 60W AND 70W. A
DIFFLUENT PATTERN ALOFT...BETWEEN THE UPPER TROUGH THAT SUPPORTS
THE FRONT AND AN UPPER-LEVEL RIDGE OVER THE CENTRAL ATLC IS
HELPING TO INDUCE THIS CONVECTIVE ACTIVITY. THE REMAINDER OF THE
DISCUSSION AREA IS UNDER THE INFLUENCE OF A 1025 MB SFC HIGH
PRES SYSTEM CENTERED NEAR 29N31W. BROAD MID TO UPPER RIDGE
COVERS THE DEEP TROPICS. THIS UPPER FEATURE IS ENHANCING
CONVECTION ALONG THE ITCZ WEST OF 38W.

$$
GR.





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