[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151725
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 15 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 21W S OF 11N MOVING W 10-15 KT. THIS
WAVE IS MORE DISORGANIZED TODAY AS VISIBLE IMAGES ONLY INDICATE
A FAINT BROAD AREA OF LOW LEVEL CYCLONIC TURNING. THE AXIS IS
PLACED IN THE CENTER OF THE BROAD STRUCTURE. SCATTERED SHOWERS
AND TSTMS ARE WITHIN 360 NM E OF THE WAVE AXIS.

A TROPICAL WAVE HAS BEEN ADDED TO THE 12Z ANALYSIS ALONG 47W S
OF 11N ESTIMATED TO BE MOVING W 15 KT. THIS WAVE HAS BEEN
TRACEABLE OVER THE PAST FEW DAYS...ESPECIALLY ON THE MIMIC TPW
ANIMATION...BUT WAS VERY MUCH EMBEDDED IN THE ITCZ. HOWEVER...
TODAY THE WAVE IS MORE DEFINED WITH VISIBLE IMAGES SHOWING
LOW-LEVEL CYCLONIC TURNING ALONG THE AXIS AND ITS ASSOCIATED
MOISTURE FIELD SLIGHTLY MORE AMPLIFIED. SCATTERED SHOWERS AND
TSTMS ARE WITHIN 360 NM EITHER SIDE OF THE AXIS S OF 6N...
ENHANCED BY LOW-LEVEL CONVERGING FLOW ALONG THE COAST OF SOUTH
AMERICA.

A WEAK TROPICAL WAVE HAS BEEN ADJUSTED W ALONG 71W S OF 13N
MOVING W 15 KT. THIS POSITION ADJUSTMENT WAS BASED ON A FAINT
MOISTURE PLUME...EVIDENT ON THE MIMIC TPW ANIMATION...TRACKING W
ALONG THE N COAST OF SOUTH AMERICA. REGARDLESS OF THE
LOCATION...THE WAVE IS WEAK AND IS NOT MUCH OF A WEATHER PLAYER
AT THE MOMENT.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N10W 7N19W 3N24W 3N46W. SCATTERED
MODERATE ISOLATED STRONG CONVECTION IS FROM 1N-6N BETWEEN
13W-20W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM OF THE
AXIS BETWEEN 28W-34W AND BETWEEN 41W-46W. SCATTERED MODERATE TO
STRONG IS FROM 6N-10N BETWEEN 52W-61W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF LIES BETWEEN A 1021 MB SFC HIGH OVER THE W ATLC AND
LOW PRES TROUGHING OVER E TEXAS AND E MEXICO. THIS PATTERN IS
PRODUCING FAIRLY UNIFORM 15-20 KT SOUTHERLY WINDS OVER THE
GULF. A SLIGHT INTERRUPTION IN THIS WIND REGIME IS ASSOCIATED
WITH A PRE-FRONTAL TROUGH THAT EXTENDS FROM NEAR HOUSTON TO
24N97W. ALOFT...A LARGE UPPER HIGH IS CENTERED OVER THE NW
CARIBBEAN AND UPPER TROUGHING EXTENDS ACROSS THE ROCKIES TO NW
MEXICO. UPPER DIFFLUENCE BETWEEN THESE FEATURES COUPLED WITH
SOME LOW-LEVEL LIFT ALONG THE PRE-FRONTAL SFC BOUNDARY IS
PRODUCING SCATTERED TO NUMEROUS TSTM ACTIVITY OVER THE SOUTHERN
U.S. AND N PORTIONS OF THE CENTRAL AND WESTERN GULF. MOST OF THE
ACTIVITY OVER THE N GULF IS MOVING INLAND...HOWEVER LONG RANGE
DOPPLER RADAR AND LIGHTNING DATA IS STILL DETECTING A BROKEN
SQUALL LINE OVER THE AL/MS/LA COASTAL WATERS AND ISOLATED
ACTIVITY ELSEWHERE N OF 28N BETWEEN 88W-94W. A COLD FRONT IS
EXPECTED TO ENTER THE NW WATERS TONIGHT.

CARIBBEAN SEA...
THE TAIL END OF A COLD FRONT REMAINS WELL DEFINED FROM THE
CENTRAL ATLC ACROSS HISPANIOLA. SAN JUAN DOPPLER RADAR AND SAT
IMAGERY REVEALS A 60 NM BAND OF LOW-LEVEL CLOUDS WITHIN EMBEDDED
SCATTERED SHOWERS AHEAD OF THE FRONT NEAR THE MONA PASSAGE AND
OVER MUCH OF THE ISLAND OF HISPANIOLA. OTHERWISE...VERY TRANQUIL
WEATHER RESIDES ACROSS THE REMAINDER OF THE BASIN IN LARGE PART
DUE TO A SPRAWLING MID-UPPER RIDGE CENTERED OVER THE NW WATERS
AND UPPER TROUGHING OVER THE E CARIBBEAN. THIS UPPER PATTERN IS
PRODUCING MODERATE TO STRONG SUBSIDENCE SUPPRESSING THE
DEVELOPMENT OF ANY SIGNIFICANT CONVECTION. TRADE WINDS ARE
FAIRLY MODEST TODAY...DUE TO THE WEAKENED SFC PRES PATTERN
BROUGHT ABOUT BY THE AFOREMENTIONED FRONT. THESE WINDS WILL
LIKELY INCREASE SLIGHTLY OVER THE NEXT DAY OR TWO AS WEAK HIGH
PRES SETTLES N OF THE AREA.

ATLANTIC OCEAN...
AN OCCLUDED 1001 MB LOW PRESSURE SYSTEM OVER THE N CENTRAL ATLC
SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR
32N53W AND EXTENDS SW TO HISPANIOLA. LOW-LEVEL CONVERGENCE ALONG
THE FRONTAL BOUNDARY COUPLED WITH UPPER DIFFLUENT FLOW IS
PRODUCING A 180 NM WIDE BAND OF SCATTERED SHOWERS AND TSTMS E OF
THE FRONT N OF 23N. SCATTERED SHOWERS NARROW TO WITHIN 60-90 NM
E OF THE FRONT S OF 23N TO HISPANIOLA. WEAK HIGH PRES IS
BUILDING SE BEHIND THE FRONT. THE REMAINDER OF THE CENTRAL AND E
ATLC IS DOMINATED BY A 1025 MB SFC HIGH LOCATED NEAR 31N39W. THE
TIGHT PRES PATTERN BETWEEN THE HIGH AND THE AFOREMENTIONED FRONT
IS PRODUCING SLY 20-30 KT WINDS WITHIN 300 NM E OF THE COLD
FRONT. IN THE UPPER LEVELS...A LONGWAVE RIDGE/TROUGH PATTERN
DOMINATES. THE TROUGH IS SUPPORTING A COLD FRONT THAT CLIPS THE
NE PORTION FROM FROM JUST E OF THE MADEIRA ISLANDS TO 30N20W TO
31N27W. ONLY A BROKEN NARROW LINE OF LOW CLOUDS MARK THE
BOUNDARY.

$$
CANGIALOSI




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