[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170529
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU 17 FEB 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
0445 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 1N24W 2N41W EQ50W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90/120 NM OF THE
AXIS FROM 18W-28W AND WITHIN 45 NM OF 3N FROM 3W-6W.

...DISCUSSION...

GULF OF MEXICO...
IN THE UPPER LEVELS...BROAD RIDGING DOMINATES THE ENTIRE AREA
WITH UPSTREAM PACIFIC MOISTURE RIDING UP AND OVER THE RIDGE
ACROSS THE S UNITED STATES AND BACK DOWN OVER N FLORIDA. AS A
RESULT...STRONG SUBSIDENCE AND DRY/STABLE AIR ALOFT PREVAILS
CAPPING SIGNIFICANT CLOUDS/CONVECTION. AT THE SURFACE...A RIDGE
EXTENDS ACROSS S FLORIDA TO THE CENTRAL GULF WITH RESULTING
RETURN FLOW OVER THE W GULF PRODUCING WARM TEMPERATURES. A 1017
MB HIGH IS IN THE E GULF NEAR 27N88W. THE RIDGE IS RETREATING
AHEAD OF THE NEXT COLD FRONT WHICH IS PRESENTLY ALONG THE TEXAS
COAST AND WILL ENTER THE NW GULF OVER THE NEXT 6 HOURS. THE
FRONT IS PRIMARILY DRY AND SHOULD ONLY BE ABLE TO PRODUCE A
NARROW BAND OF LOW CLOUDS AND ISOLATED SHOWERS ALONG THE LEADING
EDGE AS IT SWEEPS ACROSS THE GULF. THE FRONT WILL ONLY BE
ACCOMPANIED BY A MODERATE SURGE OF CONTINENTAL AIR WITH
POST-FRONTAL WINDS ON THE ORDER OF 15-20 KNOTS. PATCHES OF FOG
COULD DEVELOP ALONG THE N GULF COAST E OF THE FRONT DURING THE
EARLY MORNING HOURS.

CARIBBEAN...
MID/UPPER LEVEL RIDGE REMAINS IN PLACE OVER CENTRAL AMERICA
WITH AXIS EXTENDING FROM COLOMBIA TO SE MEXICO. THE GREATER
ANTILLES INCLUDING JAMAICA ARE UNDER A BROAD/FLAT TROUGH
EXTENDING S FROM THE W ATLC RESULTING IN ZONAL FLOW OVER MOST OF
THE E CARIBBEAN E OF 80W. STRONG SUBSIDENCE AND DRY/STABLE AIR
ALOFT CONTINUES TO DOMINATE THE ENTIRE CARIBBEAN LIMITING
SIGNIFICANT WEATHER TO SHALLOW TOPPED SHOWERS WITHIN SEVERAL
POCKETS OF LOW LEVEL MOISTURE. AN AREA OF ISOLATED SHOWERS IS
NOTED OVER THE NE CARIBBEAN N OF 15N E OF 66W TO OVER THE
LEEWARD ISLANDS N OF LOW LEVEL TROUGH EXTENDING FROM A 1009 MB
LOW IN THE CENTRAL ATLC TO 14N62W. N FLOW IS PRODUCING
OVERCAST CLOUDS AND SHOWERS OVER PORTIONS OF W PANAMA AND COSTA
RICA EXTENDING OUTWARD TO WITHIN 45 NM OF THE COAST.

ATLANTIC...
THE BULK OF THE ATLC WATERS FEATURES A FLAT UPPER LEVEL TROUGH
WITH NEAR ZONAL FLOW. A BROAD SUBTROPICAL JET CUTS ACROSS THE
AREA BETWEEN 20N-30N W OF 35W PRODUCING STRONG UPPER LEVEL WINDS
BETWEEN 90-110 KT. SHORTWAVE TROUGH OVER THE W ATLC IS PRODUCING
AN AREA OF MID/HIGH CLOUDS N OF 27N BETWEEN 60W-70W. THIS
ACTIVITY IS EXPECTED TO CONTINUE TO MIGRATE E ACROSS BERMUDA
DURING THE NEXT 6 TO 12 HOURS. AT THE SURFACE...A HIGH PRESSURE
RIDGE DOMINATES FROM E OF BERMUDA SW OVER THE N BAHAMAS AND S
FLORIDA. OVER THE CENTRAL ATLC...SURFACE LOW IS CENTERED NEAR
20N57W WITH A SURFACE TROUGH EXTENDING NE ALONG 23N54W TO 27N47W
AND SW FROM THE LOW TO OVER THE LESSER ANTILLES. THIS LOW IS
EXPECTED TO LIFT NE DURING THE NEXT 24 HOURS AND IS PRODUCING
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 150 NM OF LINE FROM 27N44W
TO TO THE LOW NEAR 20N57W. OVER THE E ATLC...A ZONALLY ELONGATED
DEEP LAYERED LOW IS LOCATED 500 NM NW OF THE CANARY ISLANDS WITH
A 1012 MB SURFACE LOW CENTERED NEAR 30N24W. SHOWER ACTIVITY WITH
THIS FEATURE IS NONEXISTENT AS THE LOW CONTINUES TO WEAKEN.
FURTHER S...VISIBLE SATELLITE IMAGERY STILL SHOWS AREAS OF
AFRICAN DUST WITH VISIBILITY POSSIBLY RESTRICTED BELOW 5 MILES S
AND E OF THE CAPE VERDE ISLANDS TO THE ITCZ. OVER THE DEEP
TROPICAL ATLC...THE ITCZ REMAINS WELL TO THE S ESSENTIALLY
STRADDLING THE EQUATOR W OF 25W.

$$
WALLACE


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