[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAY 22 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 24W S OF 12N MOVING W 10 KT. THIS WAVE
REMAINS WELL DEFINED WITH SATELLITE IMAGERY SHOWING LOW-LEVEL
CYCLONIC TURNING ALONG THE AXIS AND A CLEAR PERTURBATION IN THE
ITCZ. HOWEVER...MUCH OF THIS TURNING IS LOW LATITUDE CENTERED
NEAR 6N. SCATTERED SHOWERS AND TSTMS ARE WITHIN 150 NM EITHER
SIDE OF THE AXIS S OF 9N.

TROPICAL WAVE IS ALONG 58W S OF 10N MOVING W 10-15 KT. THE
MIMIC-TPW ANIMATION FROM CIMSS SHOWS A SMALL NORTHWARD SURGE OF
MOISTURE ALONG THE AXIS. HOWEVER...CONVECTION IS MINIMAL AND
LIKELY SUPPRESSED BY DRY MID-UPPER FLOW TO THE W OF A HIGH
AMPLITUDE TROUGH. SCATTERED SHOWERS AND TSTMS ONLY REMAIN INLAND
ACROSS E GUYANA.

TROPICAL WAVE IS OVER PANAMA ALONG 80W/81W S OF 12N MOVING W 10
KT. THIS WAVE HAS BECOME VERY DIFFICULT TO TRACK AS THE S
PORTION IS NOW EMBEDDED IN STRONG SW/W LOW-LEVEL FLOW WHICH IS
LEADING TO A BROAD AREA OF CONVECTION OVER THE TROPICAL EPAC S
OF PANAMA AND COSTA RICA. WIDELY SCATTERED SHOWERS AND TSTMS ARE
LOCATED OVER THE SW CARIB...BUT THIS SEEMS MORE ASSOCIATED WITH
THE UPPER DIFFLUENT PATTERN ALOFT.

..THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N11W 7N20W 5N26W 1N36W 1S47W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG THE W
AFRICAN COAST FROM 10N-13N BETWEEN 14W-17W. SCATTERED MODERATE
CONVECTION IS ALSO FROM 2N-4N BETWEEN 10W-13W. SIMILAR
CONVECTION IS WITHIN 60 NM OF A LINE FROM 3N42W TO 3N51W.

...DISCUSSION...

GULF OF MEXICO...
STRONG SW UPPER FLOW IS ACROSS THE GULF OF MEXICO BETWEEN A DEEP
LAYER COMPLEX LOW OVER THE ROCKIES AND MID TO UPPER RIDGING OVER
THE CARIBBEAN. DRY AIR ALOFT IS ESTABLISHED OVER THE SW
GULF...WHERE THE FLOW IS CONFLUENT...BUT IT IS STILL FAIRLY
MOIST OVER THE E HALF DUE TO A DIFFLUENT UPPER PATTERN. AT THE
SURFACE SOUTHERLY 15-20 KT WINDS ARE FAIRLY UNIFORM ACROSS THE
GULF AHEAD OF SURFACE LOW PRESSURE LOCATED ACROSS THE CENTRAL
ROCKIES. A WEAK MID-LEVEL DISTURBANCE OVER LOUISIANA IS
ENHANCING SCATTERED SHOWERS AND TSTMS ACROSS THE N CENTRAL GULF
N OF 27N BETWEEN 87W-93W AND IN THE NE WATERS N OF 26N AND E OF
86W. THIS DISTURBANCE WILL MOVE ALONG THE COAST THROUGH FRI
EVENING SUPPORTING A DEVELOPING LOW ACROSS N FLORIDA AND
ASSOCIATED FRONTAL BOUNDARY WHICH WILL DRY OUT FLORIDA AND THE
NE WATERS LATE THIS WEEKEND AND EARLY NEXT WEEK.

CARIBBEAN SEA...
AN UPPER LOW IS SPINNING OVER THE E CARIB CENTERED NEAR 14N70W.
THIS FEATURE IS ENHANCING DRY AIR ON ITS W SIDE AND IS PROVIDING
LITTLE HELP TO MOISTEN THE UPPER LEVELS TO ITS E...AS IT IS
EMBEDDED IN A SUBSIDENT ENVIRONMENT ASSOCIATED WITH BROAD LARGE
SCALE RIDGING. SCATTERED SHOWERS AND TSTMS ARE OVER THE SW/W
PORTION OF THE BASIN FROM 10N-14N BETWEEN 81W-82W. THIS ACTIVITY
IS ASSOCIATED WITH A OVERALL UPPER DIFFLUENT PATTERN AND SOME
INTERACTION WITH A NEARBY TROPICAL WAVE. MORE NUMEROUS MODERATE
CONVECTION LIES INLAND ACROSS PORTIONS OF NICARAGUA AND
HONDURAS. ASCAT WIND DATA FROM THIS AFTERNOON REVEALED SE 20-25
KT WINDS OVER THE NW CARIBBEAN WHICH CONTINUE INTO THE GULF OF
MEXICO N OF THE YUCATAN PENINSULA. ELSEWHERE E/SE TRADES OF
10-15 KT ARE OCCURRING ACROSS THE CARIBBEAN.

ATLANTIC OCEAN...
A BROAD FLAT MID TO UPPER RIDGE LIES OVER THE W ATLC PROVIDING
STABLE CONDITIONS S OF 25N. HIGH LEVEL CLOUDINESS LIES OVER THE
REGION N OF 25N W OF 50W ASSOCIATED WITH STRONG ZONAL FLOW ON
THE N PERIPHERY OF THE RIDGE. MUCH OF THE DEEPER MOISTURE LIES
JUST N OF THE AREA ASSOCIATED WITH A FRONTAL BOUNDARY. FARTHER
E...A LARGE SCALE HIGH AMPLITUDE TROUGH HAS MOVED LITTLE OVER
THE PAST DAY OR TWO. IT IS ANCHORED BY AN UPPER LOW NEAR 29N41W
AND EXTENDS SSW ALONG 40W TO NEAR 4N44W. UPPER LEVEL DIFFLUENCE
AND STRONG SW FLOW ALOFT...BETWEEN THE UPPER TROUGH AND AN BROAD
UPPER RIDGE OVER W AFRICA...IS SPREADING HIGH LEVEL CLOUDINESS
ACROSS THE E ATLC BETWEEN THE CAPE VERDE AND CANARY ISLANDS.

AT THE SURFACE...A QUASI-STATIONARY 1024 MB HIGH CENTERED NEAR
33N40W IS PROVIDING MODERATE NE/E TRADES ACROSS THE TROPICS AND
MAINLY LIGHT WINDS ACROSS THE SUBTROPICS. HOWEVER...THE
EXCEPTION TO THIS IS ON THE NW PERIPHERY N OF 29N BETWEEN 57W
AND 73W WHERE STRONG SW WINDS EXIST IN RESPONSE TO A LOW
PRESSURE SYSTEM OVER THE NW ATLC.

$$
HUFFMAN


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