[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 012356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 01 2008

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

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

...TROPICAL WAVES...

A LARGE TROPICAL WAVE IS BETWEEN AFRICA AND THE LESSER ANTILLES
ALONG 37W SOUTH OF 23N MOVING WEST NEAR 20 KT. THE CLOUD PATTERN
IS STILL EXHIBITING A WELL DEFINED CYCLONIC CIRCULATION ABOUT
TWO DEGREES IN DIAMETER WITH THE LOW LEVEL CENTER ON THE WAVE
AXIS NEAR 18N. SHOWER ACTIVITY IS VERY LIMITED IN ASSOCIATION
WITH THIS AREA OF LOW PRESSURE. ALTHOUGH ATMOSPHERIC CONDITIONS
ARE CURRENTLY NOT VERY CONDUCIVE...SLOW DEVELOPMENT OF THIS
SYSTEM IS POSSIBLE AS IT ENCOUNTERS SLIGHTLY WARMER WATERS
DURING THE NEXT COUPLE OF DAYS.

A TROPICAL WAVE EXTENDS FROM THE WINDWARD PASSAGE TO NORTHERN
COLOMBIA ALONG 74W SOUTH OF 21N MOVING WEST 20 KT. THE WAVE
PAIRED WITH AN UPPER-LEVEL LOW SPINNING OVER CENTRAL CUBA IS
GENERATING SCATTERED TO NUMEROUS SHOWERS AND TSTMS OVER PARTS OF
CUBA...HISPANIOLA AND JAMAICA. THIS WAVE WILL MOVE ACROSS THE
CENTRAL CARIBBEAN THROUGH SAT NIGHT AND INTO THE W CARIBBEAN SUN
AND MON.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 8N13W 10N25W 12N36W 8N45W
10N62W. SCATTERED MODERATE CONVECTION IS FROM 9N-13N BETWEEN
22W-26W. SIMILAR CONVECTION IS NEAR 10N35W.

...DISCUSSION...

THE GULF OF MEXICO...
LITTLE CHANGE HAS EXPERIENCED THE WEATHER PATTERN ACROSS THE
GULF OF MEXICO SINCE YESTERDAY EVENING. THE AZORES HIGH EXTENDS
A RIDGE WWD ENVELOPING THE STATE OF FLORIDA AND THE GULF OF
MEXICO. THIS FEATURE IS GIVING THE W HALF OF THE GULF SLY WINDS
OF 10 TO 15 KT WHILE MOSTLY LIGHT AND VARIABLE WINDS PREVAIL
OVER THE E HALF OF THE GULF REGION DUE TO A WEAK 1016 MB SFC
HIGH EMBEDDED IN THE RIDGE NEAR 25N84W. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE OVER THE NORTHERN GULF WATERS MAINLY E OF
93W. THIS CONVECTIVE ACTIVITY HAS PERSISTED DURING THE PREVIOUS
THREE OR FOUR DAYS LIKELY DUE TO A DIFFLUENT PATTERN ALOFT
ASSOCIATED WITH AN UPPER-LEVEL HIGH CURRENTLY LOCATED NEAR THE
LOUISIANA/TEXAS BORDER. AT THE SFC...A TROUGH IS ANALYZED OVER
THE SE CONUS EXTENDING FROM THE CAROLINAS ALL THE WAY SW TO
CENTRAL LOUISIANA. AN UPPER-LEVEL LOW IS OVER THE BAY OF
CAMPECHE. SWLY WINDS ON THE E SIDE OF THIS UPPER LEVEL FEATURE
ARE ADVECTING ABUNDANT UPPER LEVEL MOISTURE ACROSS SE MEXICO AND
THE YUCATAN PENINSULA WHERE SOME SHOWER/TSTM ACTIVITY IS
OBSERVED. THE HIGH PRES RIDGE MAY SLIGHTLY WEAKEN DURING THE
UPCOMING WEEKEND AS A TROUGH OF LOW PRES FORMS OVER THE
NORTH-CENTRAL GULF WATERS.

THE CARIBBEAN SEA...
AN EASTERLY SURGE HAS ENTERED THE E CARIBBEAN ALONG 62W MOVING W
NEAR 20 KT. IT IS ACCOMPANIED BY A LARGE CLUSTER OF SHOWERS AND
TSTMS WHICH PRODUCED WIND GUSTS UP TO 40 KT AS RECORDED BY
OBSERVATIONS IN THE WINDWARD ISLANDS THIS MORNING. LATEST SAT
PICTURES SUGGEST THAT THE ASSOCIATED CONVECTION IS WEAKENING
RAPIDLY. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG
74W. SEE TROPICAL WAVE SECTION FOR DETAILS. CLUSTERS OF MODERATE
TO ISOLATED STRONG CONVECTION ARE NOTED OVER NORTHERN VENEZUELA
PARTICULARLY NEAR THE LAKE MARACAIBO AREA. SIMILAR CONVECTION IS
OVER PANAMA AND THE SW CARIBBEAN DUE TO THE CLOSE PROXIMITY OF
THE ITCZ COMBINED WITH UPPER DIFFLUENCE. AN UPPER-LEVEL LOW
CENTERED NOW OVER CENTRAL CUBA COUPLED WITH THE ABOVE MENTIONED
TROPICAL WAVE CONTINUES TO ENHANCE CONVECTION OVER PARTS OF
CUBA...JAMAICA AND HISPANIOLA. MODERATE TRADE WINDS OF 15 TO 20
KT ARE BLOWING ACROSS THE BASIN.

THE ATLANTIC OCEAN...
THE ATLANTIC RIDGE ANCHORED ON A 1027 MB HIGH OVER THE AZORES
COVERS THE DISCUSSION AREA PRODUCING MOSTLY FAIR WEATHER AND
MODERATE TRADES. WINDS ARE STRONGEST...IN THE 20-25 KT RANGE
WITHIN 300 NM N SEMICIRCLE OF THE SFC LOW LOCATED NEAR 18N37W
AND N OF 22N E OF 26W...INCLUDING THE MADEIRA ISLANDS DUE A
TIGHT PRES GRADIENT BETWEEN THE AZORES HIGH AND LOWER PRES
INLAND OVER W AFRICA. ALOFT...THE UPPER-LEVEL LOW OVER CENTRAL
CUBA IS PRODUCING CYCLONIC FLOW OVER THE W ATLC W OF 70W. AN
UPPER-LEVEL HIGH JUST SOUTH OF BERMUDA DOMINATES THE REMAINDER
OF THE W ATLC. A SECOND UPPER-LEVEL LOW IS OVER THE CENTRAL ATLC
NEAR 27N50W AND THE THIRD ONE IS N OF AREA AND HAS A TROUGH
EXTENDING SWD INTO THE FORECAST AREA ALONG 35W/36W. AN
UPPER-LEVEL HIGH CENTERED OVER THE TROPICS NEAR 18N27W EXTENDS A
RIDGE SW TO THE WINDWARD ISLANDS AND NE VENEZUELA WHERE IS
HELPING TO INDUCE SOME SHOWER/TSTM ACTIVITY.

$$
GR







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