[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 161130
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI FEB 16 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...
CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...
NORTHEASTERN 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 6N10W 3N25W 2N30W...CROSSING THE
EQUATOR NEAR 35W...1S39W INTO NORTHEASTERN BRAZIL NEAR 2S45W.
CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90 NM
EITHER SIDE OF THE AXIS BETWEEN 15W-28W. ISOLATED MODERATE IS
WITHIN 120 NM N OF THE AXIS W OF 34W.

...DISCUSSION...
THE GULF OF MEXICO...
THE FRONTAL BOUNDARY THAT BROUGHT THE CONSIDERABLY COOLER
AIRMASS TO THE REGION APPEARS TO BE ON THE MOVE ONCE AGAIN
AFTER BEING QUASI-STATIONARY FOR THE PAST 12-24 HOURS. AS OF 09
UTC...THE COLD FRONT WAS ANALYZED FROM THE STRAITS OF FLORIDA
ACROSS THE YUCATAN PENINSULA ALONG 24N81W 21N88W 19N91W. THE
BOUNDARY IS BROKEN IN THE BAY OF CAMPECHE AND THEN CONTINUES
STATIONARY NWD ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS
TO 25N101W...CLEARLY DEFINED BY THICK LOW CLOUDS. A DENSE LOW TO
MID LEVEL CLOUD DECK IS LINGERING BEHIND THE COLD FRONT WITHIN
240 NM. ISOLATED LIGHT SHOWERS ARE EMBEDDED IN THIS REGION AS
INDICATED BY DOPPLER RADAR. THESE SHOWERS ARE A LITTLE MORE
ORGANIZED IN CENTRAL FLORIDA. THIS AREA IS FAVORED FOR MORE
PRECIP DUE TO A THIN LINE OF MOISTURE ALOFT WHICH IS ADVECTED
FROM THE EPAC BY A SUBTROPICAL JET. THE JET LIES BETWEEN A
DIGGING TROUGH OVER MUCH OF THE CENTRAL/ERN U.S. AND A STRONG
RIDGE ANCHORED IN THE PAC S OF MEX. HOWEVER...THE BIG STORY IS
THE STRONG NLY SFC WINDS WITH A GALE WARNING IN EFFECT S OF 23N
W OF 90W. THESE STRONG WINDS ARE BEING GENERATED BY A TIGHT PRES
GRADIENT THAT HAS SET UP BETWEEN THE FRONT AND A 1033 MB HIGH
OVER NE TX. THE GALE FORCE WINDS ARE NOT EXPECTED TO LAST MUCH
LONGER AS THE STRONG HIGH QUICKLY TRACKS SWD WEAKENING THE GRAD.
NWP MODELS PREDICT STRONG NLY WINDS TO BUILD BACK THIS WEEKEND
BEHIND THE NEXT COLD FRONT.

THE CARIBBEAN SEA...
A VERY BROAD STRONG UPPER LEVEL RIDGE STRETCHES ACROSS THE
REGION SUPPLYING AN ABUNDANT AMOUNT OF DRY AIR/SUBSIDENT FLOW
ALOFT SUPPRESSING ANY SIGNIFICANT TSTM ACTIVITY. THE DRIEST AIR
IS S OF 15 E OF 75W WHERE UPPER CONFLUENCE IS STRONGEST BETWEEN
TWO UPPER HIGHS EMBEDDED WITHIN THE BROAD RIDGE. BENEATH THE
STRONG MID LEVEL CAP...SMALL PATCHES OF LOW-LEVEL MOISTURE ARE
BEING STEERED BY MODERATE ELY TRADES E OF 80W. THESE WINDS
LIGHTEN AND VEER TO THE S W OF THERE IN RESPONSE TO THE SLOW
MOVING FRONTAL BOUNDARY IN THE S GULF. LOW TO MID LEVEL CLOUDS
ARE BUILDING SWD WITH THE FRONT AND BEGINNING TO COVER PARTS OF
THE YUCATAN PENINSULA AND CHANNEL. THIS FRONT IS EXPECTED TO
PUSH INTO THE NW CARIB TODAY EVENTUALLY BECOMING DIFFUSE ON SAT.
AS THE FRONT SAGS INTO THE REGION...LOW-LEVEL MOISTURE WILL BE
ON THE INCREASE AND SFC WINDS WILL TURN TO THE N-NE AND RAMP UP
AS THE PRES GRAD TIGHTENS.

THE ATLANTIC OCEAN...
A SLOW MOVING COLD FRONT ENTERS THE AREA NEAR 32N62W AND
CONTINUES SW ALONG 28N70W 25N77W THEN ACROSS THE STRAITS OF FLA.
WHILE DEEP MOISTURE APPEARS RATHER MINIMAL ALONG THE FRONT S OF
32N...FAIRLY DENSE LOW TO MID LEVEL CLOUDS...OVERRUNNING
MOISTURE...EXISTS BEHIND THE BOUNDARY WITH EMBEDDED ISOLATED
SHOWERS LIKELY. CURRENTLY THE NRN PART OF THE FRONT DOES NOT
HAVE MUCH UPPER LEVEL SUPPORT WITH THE FLOW MAINLY ZONAL OR
SWLY. HOWEVER...IT IS ON THE WAY AS A DIGGING TROUGH OVER THE
ERN U.S. NEARS. THE SFC PATTERN ACROSS THE REMAINDER OF THE ATLC
IS DOMINATED BY A 1026 MB HIGH PRES SYSTEM CENTERED NEAR 35N36W.
THIS IS SUPPLYING MOSTLY FAIR WEATHER AND MODERATE TRADES ACROSS
A GOOD PORTION OF THE CENTRAL AND E ATLC. THE MID AND UPPER
LEVEL PATTERN IS PRETTY BENIGN ACROSS MOST OF THE DISCUSSION
AREA WITH NW-WLY FLOW COMMON EXCEPT FOR THE NE CORNER WHERE THE
SRN BRANCH OF AN UPPER TROUGH LIES FROM MADEIRA TOWARD THE CAPE
VERDE ISLANDS. THIS TROUGH IS SUPPORTING A WEAK COLD FRONT WHICH
STRETCHES FROM 32N13W TO 27N20W. UPPER LEVEL CONFLUENCE TO THE W
OF THE TROUGH AXIS IS ENHANCING SUBSIDENCE FROM 24N-29N E OF
31W. OVER THE NEXT DAY OR TWO...GFS SHOWS THE SYNOPTIC SCALE
MID-UPPER LEVEL PATTERN BECOMING MORE AMPLIFIED INTO A LARGE
SCALE RIDGE/TROUGH.

$$
CANGIALOSI




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