[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON 17 JAN 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN
COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 2N20W 1N40W 1N50W 4N80W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM EQ-2N
BETWEEN 31W-35W.

...DISCUSSION...

GULF OF MEXICO...W ATLANTIC AND CARIBBEAN...
STRONG COLD FRONT ENTERS THE W ATLC NEAR 31N64W SW ACROSS THE SE
BAHAMAS THRU THE WINDWARD PASSAGE INTO THE CARIBBEAN SEA E OF
JAMAICA CONTINUING SSW TO NEAR THE COSTA RICA/PANAMA BORDER.
WIDELY SCATTERED SHOWERS ARE WITHIN 60 NM OF THE FRONT S OF 17N
WITH WIDELY SCATTERED SHOWERS AND A FEW TSTMS WITHIN 90 NM ALONG
AND AHEAD OF THE FRONT N OF 17N.  THE HEAVIER RAINS ARE CAUSED
BY A SHORTWAVE PASSING 70W N OF THE BAHAMAS WITH ENHANCED
DIVERGENCE/LIFT TO THE E AND NE OF THE SYSTEM.  BEHIND THE
FRONT...SCATTERED TO BROKEN LOW CLOUDS AND ISOLATED SHOWERS
COVER THE NW CARIBBEAN AND W GULF OF MEXICO WITH THICKER CLOUDS
OVER THE W ATLC.  THE ONLY AREA IS THAT IS MOSTLY CLOUD-FREE IS
THE NE GULF WHERE THE COOL DRY CONTINENTAL AIR HAS NOT HAD
ENOUGH TIME TO WARM AND MOISTEN UP TO PRODUCE THE LOW CLOUDS
SEEN IN THE REST OF THE REGION.  NLY WINDS OVER THE HIGH TERRAIN
OF CENTRAL AMERICA FROM HONDURAS NW THRU CENTRAL MEXICO ARE
CAUSING OVERCAST CONDITIONS ALONG WITH SHOWERS IN HIGH
ELEVATIONS.  OTHERWISE IN THE E CARIBBEAN... A VERY PLEASANT DAY
IS ONGOING WITH REDUCED TRADEWIND SHOWERS AND GENERALLY SUNNY
SKIES.  IN THE UPPER LEVELS...BROAD MID/UPPER TROUGHING PERSISTS
IN THE W ATLC WITH AXIS ALONG 75W N OF 25N WITH INDIVIDUAL
SHORTWAVES OCCASIONALLY SHARPENING THE BASE OF TROUGH.  ZONAL
FLOW COVERS THE GULF OF MEXICO AND THE CARIBBEAN SEA.  STRONG
SUBSIDENCE COVERS THE ENTIRE GULF OF MEXICO...W ATLANTIC...AND
CARIBBEAN SEA.  MOISTURE FROM THE COLD FRONT SHOULD ENTER THE
PUERTO RICO AREA BY WED WITH ENHANCED OROGRAPHIC CLOUDS/RAIN
CHANCES.


CENTRAL AND EAST ATLANTIC...
1038 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 43N33W.  A RIDGE
EXTENDS SW INTO THE AREA TO 27N60W.  EASTERLY FLOW IS PRIMARILY
S OF 27N BETWEEN 30W-60W.  A 1003 MB GALE-FORCE LOW IS OVER THE
E ATLANTIC NEAR 27N23W MOVING WSW 5-10 KT.  THE LOW IS PAST ITS
PRIME WITH AN OCCLUDED FRONT FROM 28N25W 30N20W 28N18W BECOMING
STATIONARY TO 21N20W 18N24W 19N39W.  THESE FRONTAL FEATURES ARE
BEGINNING TO WEAKEN AS THE LOW IS CUT-OFF FROM ANY BAROCLINIC
BOUNDARIES AND IS SLOWLY SPINNING DOWN.  THE LOW IS ALSO A DEEP
LAYERED LOW WITH UPPER LEVEL CYCLONIC CIRCULATION AT 27N23W.
WIDELY SCATTERED SHOWERS AND TSTMS ARE N OF 26N E OF 25W WITH
BROKEN LOW CLOUDS/ISOLATED SHOWERS N OF 22N E OF 45W. IN THE
UPPER LEVELS...A RIDGE IS OVER THE CENTRAL ATLANTIC N OF 20N
BETWEEN 50W-65W.  OVERCAST MID UPPER LEVEL CLOUDS ARE N OF 24N
BETWEEN 57W-64W.  IN THE DEEP TROPICS A STRONG SUBTROPICAL JET
IS OVERHEAD WITH CIMSS WINDS INDICATING MAX SPEEDS <100 KT AND A
LARGE PLUME OF MOISTURE IN THE MID/UPPER LEVELS SPEEDING ACROSS
THE ATLC FROM NE S AMERICA THRU THE CAPE VERDES TO W AFRICA.  A
RARE WINTER RAIN EVENT COULD OCCUR TOMORROW IN THE CAPE VERDES
AS THE COLD FRONT WEAKENS OVER THE ISLANDS AND PLENTIFUL
MID/UPPER MOISTURE CONTINUES WITH THE NEARBY SUBTROPICAL JET
PROVIDING LIFT/DIVERGENCE.

$$
FORMOSA


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