[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON JAN 14 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N13W 3N25W 3N36W EQUATOR AT 48W
INTO NE BRAZIL. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM N OF
AXIS BETWEEN 31W-36W.

...DISCUSSION...

GULF OF MEXICO...
AT 15Z...A SERIES OF SHORTWAVE IMPULSES ROTATING THROUGH A BROAD
LONGWAVE TROUGH OVER THE EASTERN THIRD OF THE CONUS IS DRIVING A
COLD FRONT DEEP INTO THE GULF OF MEXICO. THE WRN END OF THE FRONT
ATTACHES ITSELF TO A DEVELOPING 1014MB SFC LOW LOCATED IN THE BAY
OF CAMPECHE NEAR 19N94W...WHILE A SFC TROUGH WAS ANALYZED OVER THE
WRN GULF OF MEXICO FROM THE SFC LOW TO SRN TX. WITH A MODERATELY
STRONG UPSLOPE FLOW INTO THE SIERRA MADRE...SATELLITE IMAGERY
INDICATES ABUNDANT LOW-LEVEL CLOUDS BANKED THE ERN SLOPES OF THE
HIGHEST TERRAIN...POSSIBLY WITH SOME EMBEDDED LIGHT RAIN. IN
ADDITION...LOW-LEVEL CONVERGENCE NEAR THE FRONT...COUPLED WITH
STRONG SWLY WINDS ALOFT...IS TRIGGERING SCATTERED SHOWERS AND
ISOLATED TSTMS JUST NE OF THE SFC LOW. THE REMAINDER OF THE AREA IS
UNDER THE INFLUENCE OF A BUILDING LOW-LEVEL RIDGE WITH SEVERAL
CENTERS OVER THE SE U.S. ALONG THE NWRN GULF COAST/NERN MEXICO. THE
STRONG PRESSURE GRADIENT BETWEEN THE BUILDING SFC RIDGE AND RELATIVE
LOW PRESSURE OVER THE WRN CARIBBEAN SEA IS PRODUCING MODERATE TO
STRONG NE TO E WINDS ACROSS THE AREA MAINLY W OF 90W. OTHERWISE...AT
UPPER LEVELS...STRONG SWLY WINDS ARE ADVECTING UPPER LEVEL MOISTURE/
HIGH CLOUDS FROM THE EPAC ACROSS NORTH-CENTRAL MEXICO INTO THE GULF
AND THE FLORIDA PENINSULA. DURING THE NEXT FEW DAYS...A STRONG
CUT-OFF LOW MOVING ACROSS NRN MEXICO SHOULD FORCE THE DEVELOPMENT OF
A NEW SURFACE LOW OVER THE W CNTRL GULF OF MEXICO...WHICH SHOULD CUT
ACRS THE FLORIDA PANHANDLE THU AND DRAG A NEWLY-ENERGIZED COLD FRONT
THROUGH THE GULF WATERS FRI WHERE IT WILL STALL.

CARIBBEAN SEA...
IN GENERAL...A MID-LEVEL RIDGE DOMINATES THE ENTIRE AREA LIMITING
THE DEVELOPMENT OF DEEP CONVECTION. HOWEVER...THERE ARE SOME PATCHES
OF LOW-LEVEL CLOUDS FORMING OVER THE WESTERN CARIBBEAN WITHIN A
BROAD CYCLONIC FLOW.  A MORNING QUIKSCAT PASS REVEALS THAT THESE
CLOUDS AGREE WELL WITH SPEED AND DIRECTIONAL CONVERGENCE OF THE
LOW-LEVEL WINDS ALONG 81W. ELSEWHERE...A COLD FRONT OVER THE GULF OF
MEXICO HAS BEGUN TO ENTER WESTERN CUBA AND THE YUCATAN CHANNEL...
PRODUCING POCKETS OF MAINLY LOW CLOUDS. EARLY TRADE WINDS BLOWING
ACROSS THE REMAINDER OF THE CARIBBEAN ARE MOSTLY MODERATE IN
STRENGTH...EXCEPT LOCALLY STRONGER IN THE TYPICAL ZONE NEAR THE
COAST OF COLOMBIA. EXPECT THE COLD FRONT TO CONTINUE PUSHING INTO
THE NW CORNER OF THE BASIN THIS AFTERNOON...BRINGING SHIFTING AND
INCREASING WINDS UP TO 20-25 KT FROM THE N/NE IN RESPONSE TO HIGH
PRESSURE RAPIDLY BUILDING IN. TO THE EAST...A BROAD UPPER-LEVEL
RIDGE DOMINATING NRN SOUTH AMERICA IS ADVECTING MOISTURE/HIGH CLOUDS
INTO THE CARIBBEAN AT UPPER-LEVELS FROM CONVECTIVE DEBRIS WISPING
NORTHWARD FROM SOUTH AMERICA.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE AREA NEAR 31N73W THEN CONTINUES SW ACROSS
THE NW BAHAMAS INTO THE STRAITS OF FLORIDA AND WESTERN CUBA. BROKEN
LOW TO MID CLOUDS WITH EMBEDDED SHOWERS ACCOMPANY THE FRONTAL
BOUNDARY AS IT PRESSES SOUTHEAST. AHEAD OF THE FRONT...A WEAKENING
1012 MB LOW NEAR 29N60W IS DRIFTING SLOWLY N/NNE INTO THE OPEN CNTRL
ATLANTIC. VIS SATELLITE PHOTOS SHOW ONLY A SWIRL OF LOW CLOUD CLOUDS
ASSOCIATED WITH THIS FEATURE...AND THE FORECAST CALLS FOR IT TO
BECOME ABSORBED DURING THE NEXT 24 HOURS OR SO. ELSEWHERE...A SFC
TROUGH REMAINS OVER THE NORTH TROPICAL ATLC ALONG 57W/58W FROM 15N
TO 23N. SCATTERED SHOWERS ARE WITHIN 240 NM E OF THE TROUGH AXIS.
UPPER-LEVEL DIFFLUENCE IS ENHANCING SOME SHOWER ACTIVITY ACROSS THE
CENTRAL ATLC MAINLY N OF 19N BETWEEN 43W-52W. OTHERWISE...AN
EWD-MOVING SFC RIDGE...ANCHORED ON A 1029 MB HIGH CENTER NEAR
34N33W...DOMINATES THE REMAINDER OF THE FORECAST AREA. MODERATE TO
STRONG TRADES ON THE SOUTHERN SIDE OF THIS FEATURE ARE AFFECTING THE
TROPICAL ATLANTIC FROM THE NWRN COAST OF AFRICA TO 45W. FINALLY...A
JET STREAM BRANCH...WITH CORE WINDS OF 90 TO 110 KT IS SE OF AN
AMPLIFIED MID TO UPPER TROUGH EXTENDING FROM A CUT-OFF LOW NEAR
22N34W TO 15N40W.

$$
GR/TK




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