[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220544
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT 22 JAN 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
0515 UTC.

...ITCZ...

ITCZ IS CENTERED ALONG 7N12W 3N30W 1N50W.  ISOLATED MODERATE
WITHIN 45 NM OF AXIS BETWEEN 20W-25W.  SCATTERED MODERATE S OF
2.5N BETWEEN 38W-43W.  SIMILAR CONVECTION S OF 3N W OF 47W.

...DISCUSSION...

GULF OF MEXICO...
BROKEN HIGH CLOUDS HAVE OVERSPREAD THE WESTERN GULF AHEAD OF A
CUTOFF UPPER LOW OVER NORTHERN MEXICO.  UPPER RIDGING LIES OVER
THE W GULF ALONG ABOUT 91W WITH THE HIGH CLOUDS THINNING ALONG
THE SUBSIDENCE-ENHANCED EASTERN PORTION OF THE RIDGE TOWARD THE
E.  OTHERWISE GENERALLY FAIR SKIES FROM A WEAK 1020 MB HIGH A
COUPLE HUNDRED MILES N OF YUCATAN WITH RETURN MOISTURE AND A
FEW SPRINKLES MAKING ITS WAY TO THE LOUISIANA AND TEXAS COASTS.
THE NEXT FRONT WILL BARREL INTO THE GULF LATE IN THE DAY...
BRINGING THE COLDEST AIR SINCE LATE DEC INTO THE DEEP SOUTH.

CARIBBEAN SEA...
MUCH QUIETER WEATHER PATTERN THAN EARLIER IN THE WEEK AS WINDS/
SEAS HAVE CALMED CONSIDERABLY.  IN FACT... MOST OF THE TYPICAL
TRADEWIND SHOWERS ARE CONFINED S OF 14N E OF 71W WITH SOME
SHOWERS WITHIN 90 NM OF A LINE FROM THE SOUTHERN TIP OF
HISPANIOLA TO SAN ANDRES ISLAND.  PERSISTENT LOW CLOUDS/SHOWERS
ARE ALONG THE COSTA RICA/PANAMA AREAS N OF THE HIGH TERRAIN WITH
CONTINUING OROGRAPHIC LIFTING FROM MOIST NE WINDS.  THE NW
CARIBBEAN IS HIGH AND DRY WITH WEAK UPPER TROUGHING FROM THE
MID-LATITUDES SNEAKING THRU CENTRAL CUBA THRU THE CAYMANS..
BRINGING VERY DRY AIR ALOFT INTO THE REGION.  A BIT MORE UPPER
MOISTURE IS IN THE SE CARIBBEAN WITH WIDELY SCATTERED SHOWERS IN
THE WINDWARD ISLANDS.  STRONG FRONT SHOULD MOVE INTO THE NW
CARIBBEAN BY LATE SUN... SENDING ANOTHER COOL SHOT INTO THE AREA
FOR EARLY NEXT WEEK.

ATLANTIC OCEAN...
BROAD UPPER TROUGHING CONTINUES BETWEEN 40W AND FLORIDA WITH ONE
SHORTWAVE FROM JUST W OF BERMUDA THRU CENTRAL CUBA AND ANOTHER
ALONG 45W N OF 25N.  DISSIPATING FRONTAL TROUGH IS ALONG 31N62W
TO 24N70W WITH ISOLATED SHOWERS WITHIN 90 NM OF THE AXIS ALONG
WITH BROKEN LOW/MID CLOUDINESS.  SECOND SURGE OF COLD AIR IS
BEHIND A FRONT FROM JUST S OF BERMUDA TO 30N72W TO SE GEORGIAN
WITH NEARLY OVERCAST LOW CLOUDS AND WIDELY SCATTERED SHOWERS N
OF 30N W OF 60W.  SURFACE HIGH PRESSURE CONTROLS THE CENTRAL
ATLC UNTIL REACHING A COLD FRONT FROM 31N40W SW TO 18N50W WITH
WIDELY SCATTERED WEAK CONVECTION N OF 27N WITHIN 90 NM AHEAD OF
THE FRONT.  THE E ATLC IS RATHER QUIET WITH A WEAKENING 1013 MB
HIGH NEAR 24N25W AND A 1018 MB HIGH NEAR 21N37W WITH MUCH
LIGHTER WINDS THAN AVERAGE IN THE REGION.  AN UPPER TROUGH IS
FROM THE CANARY ISLANDS TO JUST E OF THE CAPE VERDES THEN 4N21W
BUT WITH LITTLE SURFACE WEATHER IMPACT OTHER THAN TO DRY OUT THE
CAPE VERDES WHICH HAD A RARE WET PERIOD THIS WEEK AND TO ENHANCE
A FEW SHOWERS WITHIN 90 NM OF 24N19W.  FARTHER S... THE DEEP
TROPICAL ATLC W OF 30W IS UNDER THE INFLUENCE OF A SPRAWLING
MID/UPPER HIGH CENTERED NEAR 1N45W RIDGING NORTHWARD TO 21N42W.
THIS HIGH IS QUITE FAR TO THE N FOR THIS TIME OF YEAR WITH UPPER
WINDS 30-35 KT WEAKER THAN NORMAL OVER THE TROPICAL ATLC.  SLY
WINDS FROM THE HIGH ARE CARRYING CIRRUS DEBRIS CLOUDS FROM S
AMERICAN AND ITCZ CONVECTION THRU THE SE CARIBBEAN ACROSS THE
TROPICAL ATLC TO ABOUT 45W.  SOME DIVERGENCE ON THE W SIDE OF
THE HIGH IS ENHANCING SHOWERS ALONG A TROUGH NEAR 57.5W S OF
14N.  WIDELY SCATTERED SHOWERS ARE S OF 10N W OF 53W.

$$
BLAKE



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