[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161737
TWDAT

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

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 1N AT THE PRIME MERIDIAN 5N16W 3N36W
2N52W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM S OF THE
AXIS BETWEEN THE PRIME MERIDIAN AND 4W AND FROM 3N-5N BETWEEN
17W-21W. ISOLATED MODERATE IS WITHIN 75 NM EITHER SIDE BETWEEN
35W-45W.

...DISCUSSION...
GULF OF MEXICO...
A STRONG COLD FRONT CONTINUES TO MOVE E...AS OF 15 UTC IS
ANALYZED FROM THE FLORIDA PANHANDLE TO S MEXICO ALONG 30N84W
27N89W 25N93W 18N94W. THIS FRONT MARKS THE BOUNDARY OF A
DISTINCT AIRMASS CHANGE. AHEAD OF THE FRONT...CONDITIONS ARE
WARM AND HUMID WITH LIGHT WINDS AND ONLY SCATTERED LOW TO MID
LEVEL CLOUDS. HOWEVER...A WEAK SFC TROUGH ALONG 82W FROM 22N-26N
IS PRODUCING SOME LIGHT SHOWER ACTIVITY IN THE E GULF AND THE FL
KEYS. BEHIND THE FRONT...NLY WINDS ARE QUITE STRONG WITH A GALE
WARNING IN EFFECT FOR THE SW GULF. THIS STRONG FLOW IS ADVECTING
MUCH COLDER AIR INTO THE REGION. AT 17Z...TEMPS ARE IN THE 30'S
AND 40'S ACROSS THE GULF COAST WARMING INTO THE 50'S FURTHER S.
CONSIDERABLE CLOUDINESS AND SCATTERED SHOWERS LINGER BEHIND THE
BOUNDARY...STRETCHING W TO THE SLOPES OF THE SIERRA MADRE IN
MEXICO...WHERE A STATIONARY FRONT MAY BE REINTRODUCED AT 18Z DUE
TO A TEMP GRAD AND BANKING OF LOW CLOUDS. ALOFT...A SUBTROPICAL
JET IS ADVECTING A LARGE PLUME OF MOISTURE FROM THE EPAC ACROSS
MEXICO...THE NW/N CENTRAL GULF INTO THE MID-ATLANTIC STATES.
LOOKING AHEAD...THE COLD FRONT WILL BEGIN TO FLATTEN IN
STRUCTURE AND WEAKEN OVER THE NEXT COUPLE OF DAYS AS ITS UPPER
LEVEL DYNAMICS MOVE E.

CARIBBEAN SEA...
THE MAIN WEATHER EVENT IN THE CARIBBEAN CONTINUES TO BE THE
STRONG WINDS AND HIGH SEA CONDITIONS WITH A GALE WARNING IN
EFFECT FOR THE S CARIB N OF THE COLOMBIAN COAST. THIS WARNING IS
CONFIRMED BASED ON SHIP AND BUOY DATA...AS WELL AS AN 1108 UTC
QSCAT PASS. THESE STRONG WINDS ARE EXPECTED TO PERSIST FOR
ANOTHER 24-48 HOURS BEFORE GRADUALLY SUBSIDING. OTHERWISE...VERY
DRY AIR IN THE MID AND UPPER LEVELS COVERS THE ENTIRE REGION
GENERATED BY CONFLUENT FLOW ALOFT BETWEEN SLIGHT RIDGING TO THE
NW... TROUGHING TO THE NE AND SW AND S-SWLY FLOW TO THE S/SE.
BENEATH THE STRONG MID-LEVEL CAP...PATCHES OF LOW LEVEL CLOUDS
AND EMBEDDED ISOLATED SHOWERS ARE SCATTERED ACROSS THE SEA.
THESE PATCHES ARE THICKER AND COVER A LITTLE MORE REAL ESTATE IN
THE NW CARIB AND PORTIONS OF HONDURAS...BELIZE AND GUATEMALA
WHERE THERE ARE A FEW REPORTS OF LIGHT TO MODERATE RAIN.
OVERALL...NUMERICAL MODELS SHOW LITTLE CHANGE IN MOISTURE ACROSS
THE CARIB OVER THE NEXT FEW DAYS AS DRY AIR ALOFT CONTINUES TO
SUPPRESS CONVECTIVE ACTIVITY.

ATLANTIC OCEAN...
THE SUBTROPICAL WRN ATLC...W OF 60W...IS DOMINATED BY NLY UPPER
LEVEL FLOW ON THE E SIDE OF A BROAD MID TO UPPER LEVEL RIDGE AND
E OF A CUT OFF UPPER LOW IN THE CENTRAL ATLC. MODERATE DRY AIR
ALOFT COVERS THIS AREA...DRIEST S OF 23N WHERE THERE IS STRONG
UPPER LEVEL CONFLUENCE. THE CUT OFF UPPER LOW MENTIONED IS
CENTERED NEAR 21N54W. THIS UPPER LEVEL SYSTEM DOES HAVE A SFC
BOUNDARY ASSOCIATED WITH IT...BASED ON SFC OBS WHICH SHOW A LOW
PRES KINK IN THE ISOBARS. IR IMAGES SUGGEST AREAS OF SCATTERED
SHOWERS ALONG AND TO THE E OF THE TROUGH BETWEEN 40W-52W FROM
18N-25N. DEBRIS MOISTURE IS THEN CARRIED E BY STRONG WLY UPPER
LEVEL WINDS ON THE S SIDE OF A DIGGING TROUGH IN THE NE PART OF
THE DISCUSSION AREA...MAINLY CONTAINED FROM 22N-27N E OF 40W.
GFS SHOWS THIS UPPER TROUGH DEEPENING AND BECOMING CUT OFF
TOMORROW N OF THE CAPE VERDE AND W OF THE CANARY ISLANDS. IN THE
TROPICAL ATLC...EXTENSIVE WLY UPPER LEVEL FLOW ON THE N SIDE OF
A VERY BROAD RIDGE IS THE RULE. THIS FLOW IS SPREADING SOME MID
AND HIGH LEVEL CLOUDINESS...WITH POSSIBLE ISOLATED SHOWERS
...ACROSS THE OCEAN FROM 9N-15N. CONVECTION IS CONFINED TO VERY
NEAR THE ITCZ...EXCEPT FOR A SMALL AREA OF SCATTERED MODERATE NE
OF S AMERICA FROM 5N-7N BETWEEN 48W-49W LIKELY ENHANCED BY
LOW-LEVEL SPEED CONVERGENCE. DUSTY AND HAZY CONDITIONS ARE BEING
REPORTED ACROSS COASTAL W AFRICA AND THE CAPE VERDE ISLANDS. AT
THE SFC...A 1030 MB HIGH DOMINATES THE REGION INTERRUPTED BY THE
SFC TROUGH IN THE CENTRAL ATLC. THE TIGHTENED PRES GRAD BETWEEN
THE TROUGH AND THE STRONG HIGH HAS SET UP A LARGE AREA OF 20 TO
25 KT WINDS ROUGHLY BETWEEN 35W-65W S OF 25N.

$$
CANGIALOSI




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