[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311148
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU JAN 31 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 1N4W 8N18W 2S44W. SCATTERED MODERATE
CONVECTION NOTED AT 9N19W AND WITHIN 60 NM EITHER SIDE LINE
2N22W 6N31W 3N42W.

...DISCUSSION...
GULF OF MEXICO...
IN THE UPPER LEVELS A NEW SHORTWAVE TROUGH IS DIGGING SE ACROSS
CENTRAL TEXAS WHILE A SHORTWAVE RIDGE...ORIGINATING FROM AN
ANTICYCLONE CENTER OVER THE CENTRAL BAHAMAS...GENTLY RIDGES
ACROSS THE AREA ALONG POINTS 21N96W 32N88W 31N75W. A BAND OF
UPPER MOISTURE IS STREAMING ENE AND EVAPORATING OVER THE
NORTHERN GULF WATERS AND OVER N FLORIDA. DRY UPPER AIR IS
INDICATED S OF A LINE
FROM W CENTRAL FLORIDA TO OLD MEXICO AT 22N97W AND DRY AIR IS
ALSO NOTED E OF THE APPROACHING FRONT OVER E TEXAS. AT THE
SURFACE
A WARM FRONT EXTENDS ALONG 28N83W 28N94W TO A WEAK AND ILL
DEFINED LOW PRES AT 27N98W 1007 MB. BROKEN TO LOCALLY OVERCAST
LOW CLOUDS WITH EMBEDDED SHOWERS ARE NOTED N OF THIS FRONT.
THE COLD FRONT WILL MOVE INTO THE NW GULF WATERS TODAY.

CARIBBEAN SEA...
IN THE UPPER LEVELS A PARENT ANTICYCLONE HAS SHIFTED N OF THE
AREA TO A POSITION OVER THE CENTRAL BAHAMAS...BUT ITS ENVELOPE
OF ANTICYCLONIC FLOW STILL DOMINATES MOST THE CARIBBEAN SEA
ALOFT. ASSOCIATED DRY UPPER AIR CONTINUES TO SUPPRESS DEEP
CONVECTIVE DEVELOPMENT. THE SOUTHERN EXTENSION OF AN ATLC UPPER
TROUGH IS STILL EVIDENT OVER THE NE CARIBBEAN ISLANDS WITH A
BASE NEAR 16N62W. THE REMNANTS OF THE ASSOCIATED SURFACE FRONT
ARE DISSIPATING ALONG 14N60W 12N71W ACCOMPANIED BY BROKEN LOW
CLOUDS AND WARM TOP SHOWERS. THE LOW LEVEL FLOW IS NE 0VEER THE
WATERS N OF THIS FRONT...ADVECTING LOCALLY BROKEN LOW CLOUDS AND
EMBEDDED LIGHT SHOWERS SW. ANOTHER AREA OF BROKEN TO OVERCAST
LOW CLOUDS IS NOTED S OF 16N BETWEEN 80W AND 85W AND IS MOVING W
IN THE BRISK EASTERLY TRADES THAT DOMINATE THE W CARIBBEAN. LOW
LEVEL RETURN FLOW HAS SET UP OVER THE NW WATERS WITH TOWERING
CUMULUS CLOUDS BEGINNING TO CONCENTRATE ALONG THE GULF STREAM
THROUGH THE YUCATAN CHANNEL.

ATLC OCEAN...
A STATIONARY FRONT EXTENDS ACROSS THE NW WATERS FROM 31N76W TO
THE FLORIDA COAST AT 29N81W ACCOMPANIED BY BROKEN LOW CLOUDS AND
LIGHT SHOWERS. AN UPPER LEVEL ANTICYCLONE HAS SHIFTED N TO OVER
THE CENTRAL BAHAMAS WITH ITS RIDGE CRESTING ALONG POINTS 30N82W
32N74W 27N65W. A BAND OF UPPER MOISTURE LIES ALONG THE NORTHERN
PERIPHERY OF THIS RIDGE...ROUGHLY WITHIN 90 NM EITHER SIDE OF
LINE 29N81W 29N70W 27N64W. A DEEP LAYERED CYCLONE IS NEAR 24N56W
AND IS SHIFTING S WITH TIME WITH AN UPPER TROUGH EXTENDING SW TO
NEAR TOBAGO AT THE MOMENT. THE SURFACE REFECTION APPEARS TO BE
OCCLUDING AT 26.5N58W 1014 MB WITH A COLD FRONT LYING ALONG
27N56W 20N54W THEN QUASI STATIONARY 10 13N61W AT 06Z. SURFACE
HIGH PRES SQUEEZED BETWEEN THIS LOW AND THE STATIONARY FRONT
OVER THE NW WATERS HAS WEAKENED TO RIDGE ALONG 32N68W TO THE DRY
TORTUGAS. DRY UPPER AIR IS INDICATED S OF 25N W OF 68W AND S OF
23N BETWEEN 68W AND 55W.

AN UPPER LEVEL TROUGH OR TUTT...WHICH EXTENDING THROUGH UPPER
CYCLONES AT 32N20W AND 27N27W WITH AN UPPER TROUGH IN TURN
EXTENDING SE TO BASE NEAR 14N15W. UPPER DIFFLUENCE ENHANCED
CONVECTION EARLIER WITH DENSE DEBRIS MOISTURE CONCENTRATED OVER
THE AREA FROM 24N TO 32N BETWEEN 35W AND 13W. AN UPPER RIDGE
EXTENDS N ACROSS THE EQUATOR CRESTING ALONG 12N60W 21N40W 23N28W
THEN THE UPPER FLOW TURNS CYCLONIC INTO THE TROUGH ALREADY
MENTIONED. THIN CIRRIFORM CLOUDS ARE NOTED ALONG THE N PERIPHERY
OF THE RIDGE WITH DENSE DEBRIS MOISTURE NOTED S OF 10N BETWEEN
30W AND 61W. AT THE LOW LEVELS BRISK NE FLOW AND LOCALLY BROKEN
STRATOCUMULUS CLOUDS ARE NOTED E OF 50W.

$$
NELSON






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