[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 232350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI JAN 23 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 3N10W TO THE EQUATOR AT 20W TO
1S30W INTO NORTHEASTERN BRAZIL NEAR 3S44W. ISOLATED MODERATE
CONVECTION IS FROM THE EQUATOR TO 4N BETWEEN 10W AND 14W.
SIMILAR CONVECTION IS ALSO NOTED WITHIN 190 NM N OF AXIS BETWEEN
30W AND 35W.

...DISCUSSION...

THE GULF OF MEXICO...
SURFACE HIGH PRESSURE CENTERED OVER N-CENTRAL FLORIDA REMAINS IN
CONTROL OF THE WEATHER PATTERN ACROSS THE ENTIRE GULF REGION
PRODUCING VERY PLEASANT WINTER CONDITIONS AND LIGHT TO MODERATE
WINDS. SOUTHERLY RETURN FLOW HAS ALREADY ESTABLISHED OVER THE
WESTERN GULF AHEAD OF THE NEXT COLD FRONT FORECAST TO MOVE OFF
THE NW GULF COAST SAT. THE FRONT WILL STALL FROM THE BIG BEND
AREA OF FLORIDA TO NE MEXICO SAT NIGHT THEN WEAKEN AND LIFT N
OF THE AREA SUN. IN THE UPPER LEVELS...A RIDGE IS OVER THE THE
GULF WITH AXIS ALONG 90W. CONSIDERABLE UPPER LEVEL MOISTURE IS
BEING TRANSPORTED BY SWLY WINDS FROM THE EPAC ACROSS N-CENTRAL
MEXICO INTO THE N GULF WATERS. MODERATE TO STRONG SUBSIDENCE AND
THE ASSOCIATED DRY AIR MASS DOMINATES THE REMAINDER OF THE
GULF.

THE CARIBBEAN SEA...
THE COLD FRONT THAT BROUGHT THE COLDEST TEMPERATURES OF THE
SEASON SO FAR HAS BECOME STATIONARY AND CURRENTLY EXTENDS FROM
THE EASTERN PORTION OF DOMINICAN REPUBLIC ALL THE WAY NE TO
BEYOND 31N55W. THIS FRONTAL SYSTEM CONTINUES TO GENERATE
ABUNDANT CLOUDINESS WITH EMBEDDED SHOWERS OVER HISPANIOLA. THE
FRONT IS EXPECTED TO DRIFT W INTO THE SE BAHAMAS THROUGH MON. A
SURFACE TROUGH EXTENDS FROM THE TAIL END OF THIS FRONT ACROSS
THE CENTRAL CARIBBEAN TO NEAR 14N72W. ISOLATED SHOWERS ARE
WITHIN 90 NM OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH IS OVER
THE GULF OF HONDURAS. THIS SECOND TROUGH HAS WEAKENED SINCE
YESTERDAY. HOWEVER...IT IS STILL GENERATING SOME LOW/MID CLOUDS
WITH MAINLY LIGHT RAIN OVER PARTS OF CENTRAL AMERICA
PARTICULARLY ACROSS BELIZE AND EASTERN NICARAGUA. HIGH PRES N OF
THE AREA MAINTAINS MODERATE TO FRESH TRADE WINDS OVER THE BASIN.
IN THE UPPER LEVELS...A RIDGE AXIS EXTENDS FROM N VENEZUELA TO
BEYOND PUERTO RICO WHERE A MUCH DRIER AND MORE STABLE ATMOSPHERE
PREVAILS. SUBSIDENCE WESTERLY WINDS OF UP TO 70 KT ARE NOTED
OVER CUBA AND THE NW CARIBBEAN N 0F 18N. THERE WILL BE NO
SIGNIFICANT CHANGE IN THE SYNOPTIC PATTERN DURING THE UPCOMING
WEEKEND.

THE ATLANTIC OCEAN...
SURFACE HIGH PRES LOCATED OVER N-CENTRAL FLORIDA EXTENDS A RIDGE
OVER THE W ATLC. ANOTHER 1031 MB SURFACE HIGH PRES CENTERED NEAR
30N28W DOMINATES MOST OF THE EAST AND CENTRAL ATLC AND IS
PRODUCING A WIDESPREAD AREA OF GENERALLY EASTERLY WINDS UP TO 25
KT. IN BETWEEN...THE AFOREMENTIONED STATIONARY FRONT WHICH
ENTERS THE AREA NEAR 31N55W. SCATTERED SHOWERS ARE WITHIN 120 NM
OF THE FRONT. ALOFT...A CLOSED UPPER-LEVEL LOW REMAINS CENTERED
AT 14N52W AND IS ADVECTING MID TO UPPER LEVEL CLOUDINESS AND
MOISTURE FROM THE ITCZ CONVECTIVE OUTFLOW ALONG ITS EASTERN
SEMICIRCLE. SHOWER ACTIVITY HAS SLIGHTLY INCREASED NEAR THE LOW
CENTER SINCE YESTERDAY. AN UPPER-LEVEL RIDGE STRETCHES FROM
22N37W E-NE TO THE MADEIRA/CANARY ISLANDS. SOUTH OF THE RIDGE...
THERE IS AN UPPER-LEVEL LOW SPINNING VERY CLOSE TO THE CAPE
VERDE ISLANDS AT 17N22W. A TROUGH EXTENDS FROM THE LOW CENTER
ACROSS THE DEEP TROPICS TO NEAR 8N30W.

$$
GR




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