[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 100535
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT MAR 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N12W 4N20W 3N30W CROSSING THE
EQUATOR NEAR 41W TO NE BRAZIL NEAR 3S46W. SCATTERED MODERATE
CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN
32W-41W...AND WITHIN 60 NM EITHER SIDE BETWEEN 17W-23W. SIMILAR
CONVECTION IS OVER NE BRAZIL.

...DISCUSSION...

GULF OF MEXICO...
STRONG ZONAL PATTERN HAS SET UP IN THE GULF SANDWICHED BETWEEN A
DIGGING SHORTWAVE TROUGH OVER THE CENTRAL/EASTERN U.S. AND WEAK
RIDGING OVER CENTRAL AMERICA. THIS STRONG MID TO UPPER LEVEL
FLOW IS SPREADING A PLUME OF MOISTURE ACROSS CENTRAL/SOUTHERN
MEXICO AND THE GULF S OF 28N. HOWEVER...MOST OF THIS IS ONLY IN
THE FORM OF BROKEN TO OVERCAST MID TO HIGH LEVEL CLOUDINESS. IN
THE LOWER LEVELS...WEAK HIGH PRES RIDGING IS THE THEME EXTENDING
SW FROM A STRONG HIGH OFF THE MID-ATLANTIC COAST. A VERY WEAK
SFC TROUGH IS NEARLY STATIONARY ALONG 89W FROM 24N-30N. A SLIGHT
WIND SHIFT OR PERTURBATION IN THE LIGHT ELY FLOW...AS DEPICTED
IN QSCAT AND SHIP OBS...IS THE BASIS FOR THIS BOUNDARY. THERE
ARE SCATTERED LOW TO MID LEVEL CLOUDS AND MAYBE AN ISOLATED
SHOWER WITHIN 180 NM E OF THE TROUGH AXIS. LOOKING AHEAD THROUGH
THE WEEKEND...THE WEAK TROUGH WILL GRADUALLY DISSIPATE AS STRONG
HIGH PRES BUILDS N OF THE REGION. THE PRES GRADIENT ON THE S
SIDE OF THE HIGH WILL INCREASE THE ELY WINDS SLIGHTLY ON SUN AND
INTO EARLY NEXT WEEK.

CARIBBEAN...
QUIET WEATHER PERSISTS ACROSS MUCH OF THE BASIN THIS EVENING
WITH PLENTY OF DRY STABLE AIR ALOFT IN PLACE. WEAK UPPER RIDGING
GENERALLY DOMINATES THE REGION AS THE SHORTWAVE TROUGH HAS NOW
PULLED E OF THE AREA. THERE ARE ONLY A COUPLE OF AREAS OF
NOTABLE CLOUDINESS. ONE IS OVER THE COLOMBIA...PANAMA...COSTA
RICA AND THE COASTAL WATERS WHERE THERE IS SMALL PATCHES OF
WEAKENING CONVECTION MOSTLY ASSOCIATED WITH CLIMATOLOGICAL LOW
PRES AND THE ITCZ. THE OTHER AREA OF CLOUDINESS IS OVER THE
ISLAND OF HISPANIOLA WHERE INFLUENCE FROM A SFC TROUGH TO THE N
AND LOCAL UPSLOPING CONDITIONS IS LIKELY PRODUCING A FEW SHOWERS
OVER THE HIGH TERRAIN. OTHERWISE MAINLY FAIR WEATHER AND TYPICAL
ISOLATED TRADE WIND SHOWERS ARE MOVING WWD ACROSS THE REGION.
TRANQUIL WEATHER IS EXPECTED TO CONTINUE THROUGH THE WEEKEND
WITH CONDITIONS DOMINATED BY MODERATE TO STRONG TRADE WINDS.

WESTERN ATLANTIC...
A LARGE AREA OF CLOUDS AND SCATTERED SHOWERS CONTINUE TO AFFECT
THE REGION. THE SFC PATTERN CONTRIBUTING TO THIS UNSETTLED
WEATHER IS SOMEWHAT COMPLEX. THE MAIN FEATURE IS A 1012 MB LOW
PRES SYSTEM CENTERED N OF THE CENTRAL BAHAMAS NEAR 25N73W WITH A
TROUGH EXTENDING SWD FROM THE LOW ACROSS HISPANIOLA. A COLD
FRONT IS APPROACHING THE LOW ENTERING THE REGION NEAR 32N48W AND
CONTINUING WSW TO 28N73W. THESE FEATURES MAY BE MERGING BASED ON
THE LATEST SATELLITE DATA. THE MID AND UPPER FLOW IS MAINLY SWLY
HELPING TO GENERATE AND ADVECT MOISTURE NEWARD N OF 21N E OF
70W. IR IMAGES SHOW A FEW PATCHES OF COLD CLOUD TOPS FROM
23N-26N BETWEEN 65W-70W WHERE LIFTING AND INSTABILITY IS
GREATEST. IN ADDITION TO THE MOISTURE...ANOTHER CONCERN IS THE
STRONG NELY WINDS AS A TIGHT PRES GRAD HAS NOW SET UP BETWEEN
THE LOW AND A 1034 MB HIGH NEAR 39N68W. LOOKING AHEAD IN
TIME...THE WEAK LOW IS EXPECTED TO INTENSIFY AND TRACK TO THE NE
MOVING OUT OF THE AREA ON SUN BUT ITS TRAILING FRONT/TROUGH WILL
REMAIN IN THE REGION LONGER. THIS WOULD INCREASE THE PRES GRAD
FURTHER THROUGHOUT THE DAY AND FOR THAT REASON A GALE WARNING IS
IN EFFECT FOR A PORTION OF THE FORECAST AREA. FOR DETAILS REFER
TO THE HIGH SEAS FORECAST...AWIPS HEADER MIAHSFAT2.

EASTERN ATLANTIC...
STRONG HIGH PRES RIDGING CONTINUES TO DOMINATE THE SFC PATTERN
ACROSS THE ATLC E OF 45W. THIS HIGH IS PRODUCING MODERATE TO
STRONG TRADE WINDS ACROSS A GOOD PORTION OF THE DISCUSSION AREA
PARTICULARLY N OF 20 E OF 30W WHERE THE TIGHTEST PRES GRAD
EXISTS. IN THE MID AND UPPER LEVELS...STRONG RIDGING IS ALSO THE
RULE WITH THE AXIS ALIGNED MAINLY N-S ALONG 28W. ABUNDANT DRY
SINKING AIR ALOFT IS WIDESPREAD AIDING IN THE FAIR WEATHER
ACROSS THIS REGION. OVER THE NEXT FEW DAYS...THE STRONG RIDGING
WILL RETREAT NE ALLOWING THE TRADES TO RELAX SLIGHTLY TODAY
ESPECIALLY IN THE E ATLC. HOWEVER THEY ARE SET TO PICK UP AGAIN
FROM W TO E SUN AND INTO NEXT WEEK AS STRONG HIGH PRES REBUILDS
E ACROSS THE ATLC OCEAN. THE UPPER RIDGE IS FORECAST TO SHIFT W
AS A SHARP TROUGH DEVELOPS IN THE E ATLC N OF THE REGION...THIS
SHOULD ALLOW FAIR WEATHER TO CONTINUE FOR THE BULK OF THE AREA.

$$
CANGIALOSI







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