[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201719
TWDAT

TROPICAL WEATHER DISCUSSION...
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI 20 MAY 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...SPECIAL FEATURES...
TROPICAL STORM ADRIAN IS NOW A DEPRESSION INLAND OVER HONDURAS
NEAR 15.0N 87.5W AT 1500 UTC MOVING NE 15 KT WITH MAXIMUM
SUSTAINED WINDS 25 KT GUSTING TO 35 KT.  THE SYSTEM IS VERY
STRETCHED OUT FROM NE TO SW WITH LITTLE CHANCE SEEN FOR
REGENERATION IN THE NW CARIBBEAN.  SEE LATEST NHC PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP1/WTPZ31 KNHC AND THE
FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21
KNHC FOR MORE DETAILS.  HEAVY RAINS ARE LIKELY OVER CENTRAL
AMERICAN BETWEEN NORTHERN COSTA RICA AND HONDURAS WITH THE DEEP
SW FLOW.  MOISTURE FROM THIS DEPRESSION IS ALREADY OVERSPREADING
THE NW CARIBBEAN E OF MEXICO WITH LOCALLY HEAVY RAINS POSSIBLE
FOR THE NEXT COUPLE OF DAYS FOR CUBA... THE CAYMAN ISLANDS...
JAMAICA AND HAITI.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE ADDED ALONG 22W NEAR THE CAPE VERDE ISLANDS
S OF 16N MOVING W 15 KT.  DAKAR TIMESECTION CLEARLY SHOWS A WAVE
PASSAGE AND VISIBLE IMAGERY TODAY SHOWS AN INCREASE IN
CONVECTION ALONG WITH SOME WEAK CURVATURE.  SCATTERED MODERATE
CONVECTION FROM 4N-8N BETWEEN 18W-24W.

TROPICAL WAVE ABOUT MIDWAY BETWEEN AFRICA AND THE WINDWARD
ISLANDS ALONG 41W S OF 15N MOVING W 10-15 KT.  POSITION IS BASED
ON LONG-TERM SATELLITE LOOPS AS WELL AS A NORTHWARD KINK IN THE
ITCZ.  THE WAVE IS NOT ESPECIALLY WELL-DEFINED AND COULD BE
FARTHER WEST.   ISOLATED MODERATE CONVECTION WITHIN 120 NM OF
5N42W.

TROPICAL WAVE IS NEAR THE ABC ISLANDS AND VENEZUELA ALONG 70W S
OF 13N MOVING W 10-15 KT.  VISIBLE SATELLITE SHOWS TWO WEAK
LOW-LEVEL CIRCULATIONS.. ONE OVER E COLOMBIA AND THE OTHER OVER
NW VENEZUELA AND THE WAVE IS ESTIMATED TO BE BETWEEN THESE
FEATURES.  THERE IS LITTLE SIGNATURE OF THE WAVE IN THE
CARIBBEAN WITH NO SIGNIFICANT CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N14W 7N23W 3N31W 4N41W 2N51W.
CONVECTION IS GREATLY ENHANCED FROM LAST WEEK.  WIDELY SCATTERED
MODERATE CONVECTION IS FROM 1.5N-4N BETWEEN 30W-50W.  SCATTERED
MODERATE CONVECTION FROM 2.5N-6N BETWEEN 25W-30W.

...DISCUSSION...

GULF OF MEXICO...
WEAK HIGH PRESSURE EXTENDS FROM NE FLORIDA TO SE TEXAS WITH
LIGHT WINDS ACROSS THE AREA.  PARTLY CLOUDY SKIES ARE THE RULE
WITH THE ONLY SIGNIFICANT RAIN ALONG A WEAK CONVERGENCE LINE
NEAR MEXICO.  ISOLATED SHOWERS/TSTMS WITHIN 45 NM OF THAT LINE
FROM 20N96W 25N97W.  INCREASING HIGH CLOUDS ARE OVER THE FAR SE
GULF... OTHERWISE THE MID/UPPER LEVELS HAVE A TROUGH FROM
CENTRAL FLORIDA TO THE BAY CAMPECHE WITH DRY AIR ALOFT W OF THE
TROUGH OVER THE REGION.  THIS TROUGH IS ADVECTING THE REMNANTS
OF ADRIAN THRU THE NW CARIBBEAN WITH THE BULK OF THE MOISTURE
EXPECTED TO REMAIN SE OF THE REGION.  THE AREA SHOULD REMAIN
UNDER THE INFLUENCE OF A DEEPER-THAN-AVERAGE UPPER TROUGH WITH
GENERALLY DRY CONDITIONS EXPECTED FOR THE FORECAST PERIOD AND
RATHER LIGHT WINDS THROUGHOUT.  A WEAK COLD FRONT IS FORECAST TO
MOVE INTO THE NE PART OF THE REGION ON SAT WITH A STRONGER
SYSTEM POSSIBLE FOR TUE.

CARIBBEAN AND W ATLC. ...
UNSETTLED/WET PATTERN CONTINUES OVER THE NW CARIBBEAN AND
CENTRAL AMERICA COURTESY OF THE REMNANTS OF ADRIAN.  MOISTURE
FROM THE SYSTEM COULD PRODUCE LOCALLY HEAVY RAINFALL WITH
LIFE-THREATENING FLASH FLOODING AND MUDSLIDES ESPECIALLY OVER
THE MOUNTAINOUS AREAS.  DEEP-LAYERED MOISTURE IS SURGING NE OUT
AHEAD OF ADRIAN PRODUCING OVERCAST CLOUDS WITH SCATTERED
SHOWERS/ISOLATED TSTMS N OF 15N W OF HAITI. THE HEAVIEST RAIN
APPEARS TO BE WITHIN 90 NM OF A LINE FROM 19N77W TO 18.5N86W
NEAR A SURFACE TROUGH. OTHER TSTMS ARE BETWEEN 12N-15N W OF 74W
IN THE SW FLOW ALL THE WAY FROM THE PACIFIC.   THE NW CARIBBEAN
SHOULD BE ON A DRYING TREND BY THE LATTER HALF OF THE WEEKEND
WITH MUCH DRIER WEATHER BY MON.  IN THE UPPER LEVELS...STRONG
MID/UPPER LEVEL HIGH IS SITTING NEAR 13N65W RIDGING WSW TO COSTA
RICA CONTROLLING THE AREA.  WET WEATHER IS LIKELY TO SHIFT
EASTWARD TO PUERTO RICO BY SUN...INTO THE LEEWARD ISLANDS BY MON
WITH UNSETTLED CONDITIONS CONTINUING IN THE SW CARIBBEAN AS
ANOMALOUSLY STRONG SW WINDS AT THE SURFACE REMAIN.

ATLANTIC...
ACTIVE WEATHER PATTERN WITH A 1008 MB LOW NEAR 23N67W DRIFTING
WESTWARD ALONG A TROUGH EXTENDS FROM THE EXTREME SE BAHAMAS TO
31N57W.  THERE IS NO  CONVECTION NEAR THE LOW BUT WIDELY
SCATTERED SHOWERS ARE FROM 22N-26N BETWEEN 62W-70W IN ADDITION
TO ISOLATED TSTMS WITHIN 90 NM OF 21N61.5W IN A CONVERGENCE ZONE
BETWEEN SW WINDS FROM THE CARIBBEAN AND ELY ATLC WINDS.  WEAK
HIGH PRESSURE LIES OVER THE W ATLC WITH THE WIND A BIT STRONGER
TO THE N OF THE LOW.   ZONAL FLOW ALOFT DOMINATES W OF 50W WITH
SOME ANTICYCLONIC CURVATURE AS GRADUALLY BENDS AROUND THE LARGE
CARIBBEAN HIGH.  A STORM IS GROWING NEAR 30N46W WITH UPPER
ENERGY CAUSING A 1006 MB LOW.  WIDELY SCATTERED MODERATE
CONVECTION IS N OF 29N BETWEEN 38W-45W IN SHARPLY DIVERGENT FLOW
DOWNSTREAM OF THE UPPER SHORTWAVE NEAR 47W.  SURFACE TROUGH IS
NEARLY STATIONARY ALONG 18N58W JUST NE OF THE LEEWARD ISLANDS TO
26N45W WITH A WEAK SURFACE LOW POSSIBLY FORMING AT THE EXTREME
SW EDGE.   ISOLATED SHOWERS ARE WITHIN 60 NM OF THE TROUGH WITH
WIDELY SCATTERED SHOWERS/TSTMS NEAR/E OF THE LOW CENTER FROM
16N-21N BETWEEN 50W-58W.  IN THE E ATLC... DEEP UPPER TROUGH IS
ALONG 31W ALL THE WAY S TO 5N34W... ENHANCING ITCZ CONVECTION.
MID/UPPER HIGH IS NEAR 25N20W JUST SW OF THE CANARY ISLANDS.
VISIBLE SATELLITE IMAGES SHOW ANOTHER SURGE OF AFRICAN DUST
EXITING W OF MAURITANIA WITH DUST PRESENT BETWEEN 9N-23N E OF
40W.  LOWER-THAN-AVERAGE SURFACE PRESSURES REMAIN THROUGHOUT THE
DEEP TROPICAL ATLC.

$$
BLAKE


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