[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 210527
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST MON 21 MAR 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 6N9W 2N16W 2N39W ACROSS THE EQUATOR
NEAR 46W TO INLAND OVER SOUTH AMERICA. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION ARE FROM 5N ACROSS THE EQUATOR
BETWEEN 13W-40W AND FROM THE EQUATOR TO INLAND OVER AFRICA E OF
10W ACROSS THE PRIME MERIDIAN. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS 45 NM OF LINE FROM 3N46W TO INLAND OVER
SOUTH AMERICA NEAR 1N51W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYERED TROUGH COVERS THE GULF WITH S STREAM SHORTWAVE
DISTURBANCE MOVING E ACROSS THE SE UNITED STATES AND IS THE
CURRENT WEATHER MAKER AS IT MOVES OVER FLORIDA. THE ATTENDANT
FRONTAL BOUNDARY HAS REMAINED INLAND OVER THE GULF COAST STATES
AND DID NOT MAKE IT INTO THE ACTUAL GULF WATERS. SURFACE TROUGH
EXTENDING FROM THE W COAST OF FLORIDA N OF TAMPA ALONG 25N87W-
24N93W-22N94W AND IS GENERATING SHOWERS AND STRONG THUNDERSTORMS
OVER THE E GULF WITHIN 90/105 NM OF THE TROUGH E OF 88W. A
SECOND S STREAM SHORTWAVE TROUGH IS CURRENTLY OVER THE THE
DESERT SW MOVING INTO W TEXAS BRINGING ANOTHER CHANGE FOR
UNSETTLED WEATHER IN THE NEXT COUPLE OF DAYS. A WEAK 1019 MB
HIGH IS CENTERED OFF THE NW COAST OF FLORIDA NEAR 30N79W. THE
SHORTWAVE AND ASSOCIATED SHOWER/THUNDERSTORM ACTIVITY SHOULD
MOVE ACROSS FLORIDA AND INTO THE NW CARIBBEAN LATER TODAY.

CARIBBEAN...
PERSISTENT MID/UPPER LEVEL RIDGE REMAINS ANCHORED FROM AN UPPER
HIGH IN THE W TROPICAL ATLC NEAR 17N55W WITH RIDGE AXIS
EXTENDING E/W. BROAD ANTICYCLONIC FLOW COVERS THE CARIBBEAN...
TROPICAL ATLC W OF THE CAPE VERDE ISLANDS...AND THE SUBTROPICAL
ATLC S OF 25N. THERE IS A SOME UPPER LEVEL MOISTURE MOVING
AROUND THE W PERIPHERY OF THE RIDGE FROM OVER CENTRAL AMERICA TO
OVER E CUBA ADVECTING PACIFIC MOISTURE ACROSS THE AREA
GENERATING CLUSTERS OF SHOWERS/THUNDERSTORMS FROM W COLOMBIA TO
BELIZE. HOWEVER...MOST OF THE AREA CONTINUES TO BE DOMINATED BY
STRONG SUBSIDENCE AND DRY/STABLE CONDITIONS ALOFT. DRY
CONDITIONS ALSO PREVAIL IN THE LOWER LEVELS LIMITING SHOWER
ACTIVITY SAVE SOME ISOLATED ACTIVITY OVER THE LESSER ANTILLES.

ATLANTIC...
STRONG MID/UPPER LEVEL RIDGING OVER THE CARIBBEAN WATERS IS
PRODUCING MAINLY SW FLOW OVER THE W ATLC. A WEAK 1013 MB SURFACE
LOW IS BETWEEN U.S. E COAST AND BERMUDA NEAR 33N72W WITH A WEAK
SURFACE TROUGH EXTENDING S TO 27N71W AND A WARM FRONT E TO OVER
BERMUDA. THIS SYSTEM IS PRODUCING OVERCAST CLOUDINESS WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF THE AREA. A SECOND
SHORTWAVE TROUGH IS MOVING INTO THE E ATLC N OF THE AREA WITH
ATTENDANT COLD FRONT EXTENDING SW THROUGH 32N23W ALONG 27N34W TO
25N49W THEN DISSIPATING STATIONARY TO 25N60W THEN AS A SURFACE
TROUGH TO THE WINDWARD PASSAGE. THE UPPER LEVEL DYNAMICS/SUPPORT
WITH THIS SYSTEM IS FOCUSED WELL N OF THE AREA BUT LOW LEVEL
MOISTURE POOLING IS PRODUCING A NARROW BAND OF ISOLATED SHOWERS
EXTENDING UP TO 120 NM E OF FRONT N OF 26N. A SECOND SURGE COLD
FRONT EXTENDS ACROSS THE AZORES THROUGH 32N34W TO 29N41W. BEHIND
THESE FRONTS...BROKEN COLD AIR STRATOCUMULUS CLOUDS ARE TO 55W.
AN ELONGATED SURFACE RIDGE SPANS ACROSS THE ATLC FROM THE CANARY
ISLANDS SW TO A 1021 MB HIGH LOCATED NEAR 21N47W. A WEAK 1020 MB
HIGH IS NW OF THE FRONTS NEAR 28N56W. THERE IS NO LARGE-SCALE
PRECIPITATION OVER THE E HALF OF THE SUBTROPICAL ATLC. FURTHER
S...MODERATE SUBSIDENCE IN THE UPPER LEVELS AND DRY AIR IN THE
LOWER LEVELS MOVING OFF W AFRICA IS LARGELY SUPPRESSING CLOUDS
AND PRECIPITATION OVER THE AREA INCLUDING THE N PORTION OF THE
TROPICAL ATLC.

$$
WALLACE


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