[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 271736
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU 27 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N0 5N10W EQ30W 2.5N44W 1N55W.
SCATTERED MODERATE CONVECTION WITHIN 75 NM OF THE AXIS BETWEEN
25W-31W. WIDELY SCATTERED MODERATE ALONG THE COAST OF S AMERICA
BETWEEN THE AMAZON DELTA AND CNTRL GUYANA.

...DISCUSSION...

GULF OF MEXICO...
A WEAK COLD FRONT HAS PUSHED OFF THE N GULF COAST AS STRONG HIGH
PRES BUILDS SWD OVER THE GREAT LAKES AND MS VALLEY. THE FRONT
EXTENDS ROUGHLY FROM 32N66W 30N77W ACROSS CNTRL FLORIDA NEAR
ORLANDO THEN DUE W TO A 1015 MB LOW JUST W OF CORPUS CHRISTI TX.
A SECOND COLD FRONT IS BEING DRAPED ALONG THE E SLOPES OF THE
SIERRA MADRES...CURRENTLY EXTENDING AS FAR S AS 27N OR NOT QUITE
TO MONTERREY. A STRONG CLOSED MID-LEVEL LOW AND BROAD UPPER TROF
EXTENDING FROM LAS VEGAS SWD ACROSS W MEXICO IS APPROACHING THE
RIO GRANDE VALLEY AND BROAD DIVERGENCE ALOFT IS PRODUCING
WIDESPREAD RAIN AND EMBEDDED ISOLATED TSTMS MAINLY OVER E TX AND
THE ADJACENT COASTAL WATERS. A SFC TROF EXTENDS S OF THE TX LOW
TO A TOPOGRAPHICALLY FORCED LOW ALONG THE COAST NEAR
TUXPAN...AND NLY FLOW ON THE BACK SIDE OF THIS FEATURE IS
PRODUCING LOW CLOUDS AND DRIZZLE OVER THE MEXICAN COASTAL
PLAINS. ELSEWHERE...BROAD UPPER LEVEL RIDGING EXTENDS OVER THE
AREA FROM THE YUCATAN CHANNEL TO LOUISIANA AND A 1021 MB HIGH
NEAR KEY WEST IS PREVENTING THE COLD FRONT FROM MAKING MUCH
HEADWAY TO THE S.

CARIBBEAN...
BROAD UPPER LEVEL SPLIT FLOW OVER CNTRL AMERICA IS RE-CONVERGING
OVER THE W CARIBBEAN WATERS AND IS PRODUCING MODERATE/STRONG
SUBSIDENCE OVER THE ENTIRE AREA. MOST OF THE SIGNIFICANT
ACTIVITY REMAINS IN THE LOW LEVELS OF THE ATMOSPHERE WHERE A
REMNANT FRONTAL TROF HAS DETACHED FROM THE PARENT FRONT OVER THE
ATLC AND HAS BEEN PICKED UP BY THE MODERATE EASTERLY TRADES. A
BAND OF SHOWERS CURRENTLY EXTENDS FROM JUST S OF PUERTO
RICO/VIRGIN ISLANDS WWD TO JAMAICA...THEN SWWD TOWARDS INTO THE
SW CARIBBEAN OFF THE COASTS OF PANAMA...COSTA RICA...AND
NICARAGUA. IN ADDITION...THE STRONG NLY FLOW AHEAD OF THIS BAND
IS KEEPING LOW CLOUDS AND DRIZZLE ALONG THE N/NE SLOPES OF THE
MTNS IN PANAMA AND COSTA RICA.

ATLANTIC OCEAN...
UPPER LEVEL ZONAL FLOW DOMINATES MUCH OF THE AREA BETWEEN THE
BAHAMAS AND AFRICA BUT A FEW MID-LATITUDE DISTURBANCES ARE
GRAZING THE NRN BOUNDARY OF THE AREA. A SHORTWAVE TROF MOVED OFF
THE NEW ENGLAND COAST OVERNIGHT AND NOW EXTENDS ALONG 65W DOWN
TO ABOUT 26N. THIS HAS SUPPORTED BROAD LOW PRES N OF BERMUDA AND
A COLD FRONT WHICH EXTENDS FROM 32N66W TO CAPE CANAVERAL
FLORIDA. WIDELY SCATTERED MODERATE CONVECTION EXTENDS UP TO 250
NM SE OF THE FRONT N OF 29N IN ACCORDANCE WITH THE STRONGEST
DYNAMICS. FARTHER E...A 1023 MB HIGH IS OVER THE CNTRL ATLC NEAR
29N45W WITH ANOTHER 1021 MB HIGH OVER THE E ATLC NEAR 26N27W.
THE RIDGE IS SPLIT...HOWEVER...BY A COLD FRONT WHICH ENTERS THE
AREA ALONG 32N30W 25N36W 22N46W...THEN AS A DISSIPATING
STATIONARY FRONT SW TO THE NRN LEEWARD ISLANDS. THIS FRONT IS
SUPPORTED BY A VIGOROUS DEEP-LAYERED LOW W OF THE AZORES BUT
THERE IS LITTLE ADVECTION OF VORTICITY S OF 32N TO SUPPORT MUCH
ACTIVITY ALONG THE BOUNDARY. ONLY ISOLATED SHOWERS ARE WITHIN 30
NM OF THE FRONT N OF 22N. THE SRN PART OF THE BOUNDARY CONTINUES
TO WEAKEN WITH ONLY A FEW SHOWERS MOVING W/NW IN THE LOW-LEVEL
EASTERLY FLOW.

COASTAL AFRICA...
A DEEP 1001 MB LOW IS CENTERED OVER CNTRL ALGERIA ALONG THE
PRIME MERIDIAN NEAR 27N AND AN ASSOCIATED SFC TROF IS SWINGING
SWD TO THE W OF THE LOW ALONG 27N10W 31N22W. THE TROF HAS
FRONT-LIKE FEATURES AND IS MARKED AS THE LEADING EDGE OF A
BROKEN STRATOCU FIELD WHICH IS DROPPING S FROM PORTUGAL TOWARDS
THE CANARY ISLANDS AND COAST OF MOROCCO. THE ATMOSPHERE DRIES
OUT CONSIDERABLY FARTHER S AND A PLUME OF AFRICAN DUST CONTINUES
TO STREAM OFF THE CONTINENT WITHIN 300 NM OF A LINE FROM ABOUT
GUINEA-BISSAU TO 4N34W ALONG THE ITCZ.

$$
BERG


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