[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170530
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN 17 APR 2005

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N10W 4N18W 3N30W 1N43W 1N52.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM N OF THE
AXIS FROM 32W-38W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS WITHIN 75 NM S OF THE AXIS FROM 23W-26W AND WITHIN 90 NM N OF
THE AXIS FROM 24W-32W. SCATTERED CLUSTERS OF SIMILAR CONVECTION
ARE S OF 5N E OF 23W TO ACROSS THE PRIME MERIDIAN.

...DISCUSSION...

GULF OF MEXICO...
A 1031 MB HIGH IS CENTERED OVER S PENNSYLVANIA WITH A RIDGE
EXTENDING S WELL INTO THE GULF OF MEXICO WITH THE RIDGE BANKED
AGAINST THE E SLOPES OF THE SIERRA MADRES. WEAK ONSHORE FLOW
ALONG THE COAST OF MEXICO IS PRODUCING OROGRAPHIC CLOUDINESS
INTO CENTRAL MEXICO AND NOT QUITE REACHING THE IMMEDIATE
COASTLINE. A MID/UPPER TROUGH EXTENDS FROM OVER THE CAROLINAS
WSW AND IS TURNING THE UPPER FLOW PRIMARILY OUT OF THE NW...WITH
MODERATE SUBSIDENCE SWEEPING ACROSS THE E GULF NEAR A WEAK
SHORTWAVE STRETCHING FROM APALACHEE BAY TO THE YUCATAN CHANNEL.
OVERALL SKIES ACROSS THE GULF ARE FAIR WITH ISOLATED PATCHES OF
MAINLY LOW/MID LEVEL CLOUDS. THIS PATTERN WILL REMAIN IN PLACE
FOR AT LEAST THE NEXT 48 HRS.

CARIBBEAN...
A DISSIPATING FRONTAL TROUGH IS NEARLY STATIONARY OVER THE W
PART OF THE CARIBBEAN STRETCHING FROM THE S COAST OF HAITI TO
JUST OFFSHORE KINGSTON JAMAICA TO NEAR SAN ANDRES ISLAND OFF THE
COAST OF NICARAGUA. UNIFORM N/NE FLOW AROUND THE TROUGH YET
THERE IS STILL ENOUGH LOW-LEVEL CONVERGENCE AND MOISTURE TO
PRODUCE ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS WITHIN 200
NM NW OF THE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS S OF 12N TO INLAND OVER W PANAMA AND COSTA RICA FROM 80W-84W.
AN AMPLIFIED UPPER RIDGE STRETCHES FROM THE TRINIDAD/TOBAGO AREA
N OVER THE LESSER ANTILLES THEN NE OVER THE CENTRAL ATLC. THIS
IS ALLOWING DEEP TROPICAL MOISTURE TO BE ADVECTED N OVER THE
CENTRAL CARIBBEAN. ELSEWHERE...THE ISLANDS OF PUERTO RICO
THROUGH THE LESSER ANTILLES ARE UNDER THE INFLUENCE OF FAIR
SKIES AND LIGHT EASTERLY TRADES.

WEST ATLANTIC...
STRONG HIGH PRESSURE OVER THE EASTERN U.S. IS INTERACTING WITH A
1007 MB GALE CENTER NEAR 31N70W WITH THE UPPER LOW LOCATED ABOUT
280 NM WNW OF BERMUDA NEAR 35N69W TO PRODUCE GALE FORCE WINDS TO
THE SE U.S. COAST AND GALE CONDITIONS S TO 31N. EVEN THOUGH THE
LOW HAS STARTED TO WEAKEN AND THE SYSTEM REMAINS ASSOCIATED WITH
AN ELONGATED OCCLUDED FRONT WHICH STRETCHES WELL NE OF BERMUDA.
A COMPLEX UPPER LOW/TROUGH IS LOCATED OVER THE SYSTEM IN A
GENERALLY NE/SW ORIENTATION WITH A VIGOROUS SHORTWAVE SCREAMING
N OF BERMUDA. COLD/STATIONARY FRONT ENTERS THE AREA ALONG 32N58W
INLAND OVER HISPANIOLA NEAR 20N70W TO THE S COAST OF HAITI.
OVERCAST LOW/MID CLOUDS WITH ISOLATED SHOWERS ARE WITHIN 180/225
NM E OF THE FRONT. WITH THE FRONT LAGGING OVER THE ISLAND OF
HISPANIOLA...THERE IS THE POSSIBILITY OF ISOLATED FLASH FLOODING
ESPECIALLY OVER THE DE-FORESTED AREAS OF HAITI.

CENTRAL/EAST ATLANTIC...
A STRONG SUBTROPICAL HIGH IS CENTERED ABOUT 400 NM SW OF THE
AZORES NEAR 33N33W AND IS PRODUCING CONSISTENT NE/E TRADE WINDS
ACROSS MOST OF THE ATLC E OF 55W. LONGWAVE UPPER TROUGH EXTENDS
FROM A WEAK UPPER LOW CENTERED NEAR 21N34W WITH A CYCLONIC FLOW
EXTENDING OUT UP TO 800 NM TO THE S/SW WHICH IS DRAGGING MUCH
DRIER UPPER LEVEL AIR INLAND OVER AFRICA. THE SUBTROPICAL JET
HAS WEAKENED AND SHIFTED WELL S OF THESE LOWS EXTENDING FROM THE
N LEEWARD ISLANDS TO 12N40W PAST THE CAPE VERDE ISLANDS TO
INLAND OVER AFRICA NEAR 21N16W WITH THE FASTEST WINDS NOW INLAND
OVER N MAURITANIA. QUICK WESTERLY FLOW OVER THE ITCZ HAS
IMPEDED ORGANIZED DEEP CONVECTION.

$$
WALLACE


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