[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE 25 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 5N10W 1N30W 8N45W 4N60W. SMALL AREA
OF WIDELY SCATTERED MODERATE WITHIN 60 NM EITHER SIDE OF
BOUNDARY BETWEEN 49W-56W INCLUDING FRENCH GUIANA AND SURINAME.

...DISCUSSION...

GULF OF MEXICO...
THERE HAS BEEN LITTLE OVERALL CHANGE IN THE PATTERN DURING THE
LAST 24 HOURS AS A 1020 MB SURFACE HIGH PRES REMAINS ANCHORED
OVER THE CENTRAL GULF.  RESULTING PRESSURE GRADIENT HAS RELAXED
CONSIDERABLY SINCE THE WEEKEND WITH WIND/SEAS NOW DOWN OVER THE
ENTIRE GULF.  EAST OF THE SURFACE HIGH...NLY FLOW IS MAINTAINING
THE COOL/DRY PATTERN OVER THE E GULF AND FLORIDA WHILE RETURN
FLOW HAS HAS BECOME ESTABLISHED OVER THE W GULF PRODUCING A
WARMING TREND.  A WEAK COASTAL TROF AND A SMALL AREA OF BROKEN
CLOUDINESS/SHOWERS HAS FORMED JUST OFFSHORE OF TEXAS INTO S
LOUISIANA. OTHERWISE...MOST OF THE AREA IS RELATIVELY CLEAR SAVE
SOME LEFT OVER COLD AIR STRATOCUMULUS CLOUDS OVER THE CENTRAL
GULF...WHICH INTERESTINGLY ENOUGH...ACTUALLY REVEALS THE
ANTICYCLONIC FLOW AT THE LOWER LEVELS.  AT THE UPPER
LEVELS...BROAD MIDDLE TO UPPER LEVEL RIDGING PREVAILS WITH MEAN
AXIS ALIGNED OVER MEXICO. CONFLUENCE E OF THE AXIS IS PRODUCING
SUBSIDENCE AND DRY/STABLE CONDITIONS ALOFT.

CARIBBEAN...
CENTRAL ATLC COLD FRONT ENTERS THE NE CARIBBEAN NEAR THE VIRGIN
ISLANDS WHERE IT BECOMES STATIONARY AND DISSIPATING TO 13N73W.
WHILE THE FRONT LACK SIGNIFICANT MIDDLE AND UPPER LEVEL
SUPPORT...LOW LEVEL MOISTURE POOLING ALONG THE BOUNDARY IS
PRODUCING WIDESPREAD CLOUDINESS AND SCATTERED SHOWERS WITHIN 200
NM EITHER SIDE OF THE BOUNDARY INCLUDING PUERTO RICO AND THE
LEEWARD ISLANDS.  BEHIND THE FRONT...HIGH PRES OVER THE GULF OF
MEXICO HAS PUSHED SWD INTO THE W CARIBBEAN AND MOST OF THE
POST-FRONTAL CLOUDINESS FROM YESTERDAY IS ERODING AS DRIER AIR
MOVES IN. PATCHY CLOUDINESS AND SHOWERS REMAIN OVER CNTRL
AMERICA FROM GUATEMALA TO PANAMA AS THE NLY FLOW IMPINGES ON THE
HIGHER TERRAIN.  THE UPPER LEVEL PATTERN OVER THE CARIBBEAN IS
PRIMARILY ZONAL WITH A WEAK RIDGE ALIGNED ALONG CENTRAL AMERICA
AND THE BASE OF LARGE TROUGH OVER THE CENTRAL ATLC CLIPPING THE
NE CARIBBEAN.

ATLANTIC OCEAN...
A BROAD MIDDLE TO UPPER TROF COVERS THE W HALF OF THE ATLC WITH
ATTENDANT COLD FRONT EXTENDING FROM 32N44W TO THE NRN LEEWARD
ISLANDS.  THE STRONGEST DYNAMICS/LIFT WITH THE UPPER TROUGH
REMAIN N OF THE AREA WITH NO DEEP CONVECTION NOTED ALONG THE
FRONTAL BOUNDARY.  HOWEVER...BROKEN LOW TO MID LEVEL CLOUDINESS
AND SCATTERED SHOWERS CONTINUE WITHIN 360 NM E OF THE FRONT.
BEHIND THE FRONT...POST-FRONTAL NORTHERLY FLOW AND COLD AIR
ADVECTION CONTINUE TO PRODUCE A FIELD OF OPEN CELLULAR
STRATOCUMULUS CLOUDS WITH A REINFORCING FRONT NOW ENTERING THE
AREA FROM BERMUDA TO N FLORIDA.  FARTHER E...A HIGH AMPLITUDE
RIDGE EXTENDING FROM THE CENTRAL TROPICAL ATLC NEAR 10N50W NEWD
TOWARD THE AZORES BEYOND 32N35W IS MAINTAINING DRY/TRANQUIL
CONDITIONS.  AT THE SURFACE...A BROAD 1023 MB SFC HIGH IS
LOCATED NEAR 29N28W WITH ASSOCIATED RIDGE EXTENDING SW TO
15N50W. ENHANCED PRESSURE GRADIENT BETWEEN SURFACE RIDGE AND
AFOREMENTIONED CENTRAL ATLC FRONT IS MAINTAINING STRONG SLY FLOW
TO GALE FORCE N OF 20N BETWEEN 40W-50W.  OVER THE FAR E
ATLC...EARLIER VISIBLE IMAGERY CONTINUES TO INDICATED A PLUME OF
DUST OFF THE AFRICAN W COAST SE OF A LINE ALONG 32N19W 10N40W
3N50W. THE ASSOCIATED DRY AIR IS PRODUCING A NOTICEABLE ABSENCE
OF CLOUDINESS OVER THIS AREA.

$$
RHOME


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