[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAY 16 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...

A TROPICAL WAVE IS ALONG 30W S OF 11N MOVING W 15 KT. SATELLITE
IMAGERY INDICATES SOME CYCLONIC TURNING ALONG THE WAVE AXIS NEAR
7N. SCATTERED SHOWERS AND TSTMS ARE WITHIN 100 NM W AND 180 NM E
OF THE AXIS S OF 8N. THE SSMI-DERIVED TOTAL PRECIPITABLE WATER
ALSO CONFIRMS THE EXISTENCE OF THIS WAVE.

A TROPICAL WAVE IS APPROACHING FRENCH GUIANA. THIS WAVE IS
DISORGANIZED WITH THE AXIS IS ALONG 51W/52W S OF 11N MOVING W
10-15 KT. A DIFFLUENT PATTERN ALOFT IS ENHANCING CONVECTION OVER
FRENCH GUIANA AND SURINAME WHILE ISOLATED TO SCATTERED SHOWERS
ARE WITHIN 60 NM EITHER SIDE OF AXIS S OF 8N.

AN ILL-DEFINED TROPICAL WAVE IS OVER WESTERN COLOMBIA ALONG
76W/77W S OF 12N MOVING W 10-15 KT. A SMALL BULGE OF MOISTURE ON
THE MIMIC-TPW ANIMATION SUGGESTS THE PRESENCE OF THIS WAVE THAT
MAY BE ENHANCING SOME SHOWER ACTIVITY NEAR THE COLOMBIA/PANAMA
BORDER.

..THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N10W 6N27W 5N32W 2N42W 4N50W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 250 NM S
OF AXIS BETWEEN 10W-15W. SCATTERED MODERATE CONVECTION IS FROM
EQUATOR TO 4N BETWEEN 35W-45W. CLUSTERS OF MODERATE TO STRONG
CONVECTION ARE OVER SIERRA LEONE AND LIBERIA.

...DISCUSSION...

GULF OF MEXICO...
A LATE SEASON COLD FRONT IS MOVING SLOWLY SE ACROSS THE GULF
THIS EVENING. AS OF 2100 UTC...THE FRONT EXTENDS FROM A WEAK
1013 MB LOW THAT HAS DEVELOPED ALONG THE MS/LA COAST TO THE
MEXICAN COAST NEAR 24N98W. A PREFRONTAL TROUGH RUNS FROM 25N92W
TO THE BAY OF CAMPECHE. A BAND OF MULTILAYERED CLOUDS WITH
EMBEDDED SHOWERS AN ISOLATED TSTMS IS ASSOCIATED WITH THE FRONT
ACROSS THE GULF. MOSAIC DOPPLER RADAR FROM THE SE U.S. SHOWS AN
SQUALL LINE MOVING AHEAD OF THE FRONT OVER N FLORIDA AND SE
GEORGIA WHILE LIGHTNING DATA REVEALS ISOLATED TSTMS NEAR THE SFC
LOW. LITTLE CHANGE HAS EXPERIENCED THE WEATHER PATTERN ALOFT. A
LARGE UPPER-LEVEL HIGH REMAINS CENTERED OVER THE NW CARIBBEAN
EXTENDING A RIDGE OVER THE ENTIRE GULF WHILE A DEEP LAYERED
TROUGH/LOW IS OVER NW MEXICO. SWLY AND THEN WLY WINDS BETWEEN
THESE TWO UPPER LEVEL FEATURES ARE ADVECTING ABUNDANT UPPER
LEVEL MOISTURE FROM THE EPAC THROUGH MEXICO INTO THE NORTHERN
GULF WATERS. THESE WINDS ARE ALSO ENHANCING CONVECTION OVER
PARTS OF MEXICO AND NORTHERN FLORIDA. AHEAD OF THE FRONT...SFC
RIDGING IS HANGING ON WITH ITS ASSOCIATED S TO SW FLOW PROVIDING
A WARM AND HUMID DAY OVER FLORIDA AND THE REMAINDER OF THE GULF
WATERS. THIS FRONT WILL MAKE A LITTLE MORE PROGRESS SE THROUGH
TOMORROW BEFORE BECOMING STATIONARY AND WEAKENING.

CARIBBEAN SEA...
THE TAIL END OF A DISSIPATING FRONTAL SYSTEM EXTENDS TO NEAR THE
VIRGIN ISLANDS WHERE IS GENERATING ONLY SCATTERED LOW CLOUDS.
FRAGMENTS OF LOW LEVEL CLOUDS ASSOCIATED WITH ITS REMNANTS
PERSIST OVER PUERTO RICO...HISPANIOLA AND JAMAICA. SCATTERED
SHOWERS AND TSTMS ARE OVER THE SRN WINDWARD ISLANDS POSSIBLY
ASSOCIATED WITH THE TRADE WINDS SPEED CONVERGENCE AND ENHANCED
BY UPPER DIFFLUENCE. OTHERWISE...THE REMAINDER OF THE REGION IS
EXPERIENCING FAIR WEATHER UNDER THE INFLUENCE OF A MID/UPPER
RIDGE ANCHORED ON A HIGH NEAR THE CAYMAN ISLANDS AND UPPER
TROUGHING OVER THE EASTERN CARIBBEAN. WEAK HIGH PRES N OF THE
AREA COMBINED WITH THE ABOVE MENTIONED FRONT IS PRODUCING FAIRLY
MODEST TRADE WINDS ACROSS THE REGION. ACCORDING TO THE GFS
COMPUTER MODEL...MOISTURE FROM THE REMNANTS OF THE FRONT WILL
CONTINUE TO AFFECT THE GREATER ANTILLES FROM PUERTO RICO TO
JAMAICA DURING THE NEXT 18 TO 24 HOURS.

ATLANTIC OCEAN...
SFC HIGH PRES SYSTEMS DOMINATE MOST OF THE FORECAST AREA WITH A
COLD FRONT IN BETWEEN. FROM WEST TO EAST...A 1019 MB HIGH IS
OVER THE W ATLC NEAR 27N68W EXTENDING A RIDGE OVER SOUTH
FLORIDA...CUBA AND THE BAHAMAS. A COLD FRONT ENTERS THE REGION
NEAR 31N49W THE CONTINUE SW TO TO THE VIRGIN ISLANDS WHERE IT
BECOMES STATIONARY. UPPER DIFFLUENCE AND LOW-LEVEL CONVERGENCE
IS PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 300 NM
E OF THE FRONT N OF 24N. A 1025 MB HIGH LOCATED SW OF THE AZORES
NEAR 35N36W COVERS THE REMAINDER OF THE E-CENTRAL ATLC. AN E-W
TROUGH IA ANALYZED ON THE 18 Z MAP ALONG 27N/28N BETWEEN THE
CANARY ISLANDS AND 27W. A BROKEN BAND OF LOW/MID CLOUDS WITH
EMBEDDED SHALLOW SHOWERS IS ASSOCIATED WITH THIS TROUGH.
ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE FORECAST
REGION. THE UPPER TROUGH OVER THE CENTRAL ATLC SUPPORTS THE
PREVIOUSLY MENTIONED COLD FRONT. OVER THE DEEP TROPICS...MORE OF
THE SAME...AN ELONGATED RIDGE WITH AXIS ALONG 10N REMAINS
BETWEEN AFRICA AND THE WINDWARD ISLANDS.

$$
GR





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