JustWeather.com

AXNT20 KNHC 202355
TWDAT
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.
...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 10N12W 6N25W 7N44W 7N60W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 3N-7N BETWEEN 24W-32W.
SIMILAR CONVECTION IS FOCUSED ALONG A SURFACE TROUGH EMBEDDED
WITHIN THE ITCZ FROM 12N42W TO 5N45W. THE CONVECTION COVERS AN
AREA FROM 7N-10N BETWEEN 39W-48W.
...DISCUSSION...
GULF OF MEXICO...
AS OF 2100 UTC...A 1010 MB LOW IS CENTERED OFF THE COAST OF
TEXAS NEAR 27N95W. A WARM FRONT EXTENDS E FROM THE LOW TO
26N90W. A SURFACE TROUGH ALSO EXTENDS S FROM THE LOW CENTER TO
24N98W. 25 KT WINDS ARE NOTED OVER THE NW GULF OF MEXICO IN
VICINITY OF THE LOW. WIDELY SCATTERED MODERATE CONVECTION IS
FROM 25N-30N BETWEEN 90W-94W. IN THE UPPER LEVELS...ZONAL FLOW
COVERS THE GULF. SIGNIFICANT UPPER LEVEL MOISTURE IS OVER THE N
GULF N OF 26N. STRONG SUBSIDENCE COVERS THE S GULF. EXPECT THE
SURFACE LOW TO MOVE TO THE MISSISSIPPI COAST IN 24 HOURS WITH A
TRAILING COLD FRONT EXTENDING S TO THE YUCATAN PENINSULA AND A
WARM FRONT OVER THE FLORIDA PANHANDLE. EXPECT 15-20 KT N WINDS W
OF THE COLD FRONT AND 10 KT S WINDS E OF THE COLD FRONT. ALSO
EXPECT CONVECTION TO BE ALONG THE WARM FRONT OVER N FLORIDA AND
E OF THE COLD FRONT OVER THE S GULF OF MEXICO.
CARIBBEAN SEA...
MODERATE TO FRESH TRADEWINDS DOMINATES THE BASIN. A 1004 MB LOW
IS CENTERED INLAND OVER N COLOMBIA NEAR 8N75W. WIDELY SCATTERED
MODERATE CONVECTION IS FROM 4N-9N BETWEEN 75W-79W. PATCHES OF
BROKEN TO OVERCAST LOW CLOUDS DOTS THE CARIBBEAN AND CENTRAL
AMERICA NAMELY OVER THE WINDWARD ISLANDS S OF 14N AND E OF
62W...OVER PUERTO RICO...HISPANIOLA...AND THE NW CARIBBEAN FROM
17N-22N BETWEEN 82W-90W. SIMILAR SHOWERS ARE OVER THE SW
CARIBBEAN S OF 11N. IN THE UPPER LEVELS...A BROAD RIDGE IS
PRODUCING ZONAL FLOW OVER THE ENTIRE CARIBBEAN. DRY AIR AND
SUBSIDENCE COVERS THE ENTIRE AREA WITH UPPER LEVEL MOISTURE
REMAINING ONLY OVER N COLOMBIA. EXPECT...SHOWERS/THUNDERSTORMS
TO CONTINUE OVER THE SW CARIBBEAN OVER THE NEXT 24 HOURS. ALSO
EXPECT...SIMILAR CONVECTION OVER THE WINDWARD ISLANDS.
ATLANTIC OCEAN...
A 1012 MB LOW IS OVER THE W ATLANTIC NEAR 32N75W. A SURFACE
TROUGH EXTENDS S FROM THE LOW TO THE CENTRAL BAHAMAS NEAR
25N75W. SCATTERED SHOWERS ARE WITHIN 180 NM OF THE TROUGH AXIS.
ANOTHER SURFACE TROUGH IS OVER THE W ATLANTIC N OF PUERTO RICO
ALONG 25N64W 19N66W. SCATTERED SHOWERS ARE WITHIN 240 NM E OF
THIS TROUGH AXIS. A LONG STATIONARY FRONT IS OVER THE ATLANTIC
ALONG 32N26W 29N33W TO AN EMBEDDED 1015 MB LOW NEAR 27N51W TO
30N64W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 25N-28N
BETWEEN 46W-52W...AND FROM 28N-31N BETWEEN 59W-68W. FURTHER E
...A RIDGE AXIS EXTENDS FROM S PORTUGAL TO SW OF THE CANARY
ISLANDS NEAR 25N27W. EXPECT THE LOW OVER THE W ATLANTIC TO MOVE
NE OVER THE NEXT 24 HOURS LEAVING THE TAIL END OF A SURFACE
TROUGH OVER THE AREA S OF 30N. ALSO EXPECT MORE CONVECTION OVER
THE CENTRAL ATLANTIC FROM 20N-32N BETWEEN 40W-55W DUE TO THE
CENTRAL ATLANTIC LOW OVER THE NEXT 24 HOURS.


forecast by FORMOSA
updated at 705 PM EST FRI NOV 20 2009

AXPZ20 KNHC 210351
TWDEP
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT NOV 21 2009
TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
THE EQUATOR TO 32N...EAST OF 140W.
BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0215 UTC.
...ITCZ...
THE ITCZ AXIS EXTENDS FROM 05N76W TO 04N83W TO 06N89W TO 08N120W
TO 07N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
WITHIN 240 NM N OF AXIS AND 90 NM S OF AXIS W OF 118W.
...DISCUSSION...
W OF 115W...A DEEP LAYER TROUGH EXTENDING FROM JUST INLAND ALONG
THE COASTS OF WASHINGTON-OREGON-N CAL TO 34N121W CONTINUED TO
DIG E-SE ON THE EAST SIDE OF REX BLOCK CENTERED ON THE LARGE
RIDGE N OF HAWAII. AN ASSOCIATED COLD FRONT EXTENDS FROM CENTRAL
CALIFORNIA TO 30N128W TO 28N40W AND CONTINUES W TO W-NW AS A
SHEAR AXIS. THE FRONT WAS SHIFTING E-SE INTO CENTRAL CALIFORNIA
AND APPROACHING NE PORTIONS OF THE FORECAST AREA. A 1020 MB HIGH
NEAR 27N132W HAS COLLAPSED...WITH THE STRONGER CENTRAL PACIFIC
RIDGE...CENTERED ON A 1027 MB SURFACE HIGH ALONG 34N AND N OF
HAWAII...WAS SLIDING AND BUILDING EWD BEHIND THE COLD FRONT.
MORNING SCATTEROMETER PASSES SHOWED MODERATE TO FRESH 20-25 KT
TRADE WINDS S OF THE HIGH PRES FROM GENERALLY 20-22N TO THE NRN
FRINGES OF THE ITCZ ALONG 07.5N FROM 114W WWD BEYOND 140W. THE
RESULTANT WIND WAVES WERE MIXING WITH A FADING PULSE OF NW SWELL
TO PRODUCE SEAS OF 8 TO 11 FT N OF 10N AND W OF 115W...WITH SEAS
UP 12 TO 14 FT FROM 17N138W DOWNWIND...IN THE STRONGEST NE TRADE
WIND FLOW. FARTHER E...THE TRADE WIND FLOW HAS DIMINISHED
SLIGHTLY FROM YESTERDAY AS THE HIGH TO THE NORTH HAS COLLAPSED.
THESE FRESH TRADES TO THE W WILL EXPAND AND SPREAD FARTHER E
DURING THE NEXT 24-36 HOURS AS THE CENTRAL PACIFIC HIGH
CONTINUES TO BUILD E BEHIND THE FRONT N OF THE AREA. THE FRONT
ITSELF IS EXPECTED TO BECOME DIFFUSE BY SAT NIGHT ACROSS NE
PORTIONS OF THE AREA AS THE ASSOCIATED UPPER DYNAMICS LIFT OUT.
MEANWHILE DIVERGENT FLOW ALOFT ON THE RIGHT REAR ENTRANCE AREA
OF A WEAK JET MAX ON THE SE SIDE OF THE UPPER TROUGH IS
INTERACTING WITH THE MODEST TRADE WIND CONVERGENCE TO ENHANCE
SCATTERED CONVECTION N OF THE ITCZ W OF 118W. LOOKING AHEAD THE
WEEKEND...THE BLOCKING RIDGE N OF HAWAII WILL BREAK DOWN AHEAD
OF AN APPROACHING CENTRAL PACIFIC TROUGH. THIS WILL ALLOW THE
SURFACE RIDGE THAT HAS BEGUN TO BUILD BEHIND THE CURRENT
WEAKENING W COAST COLD FRONT TO REMAIN IN PLACE N OF THE
AREA...MAINTAINING A BROAD SWATH OF FRESH TO STRONG TRADES FROM
10N TO 25N W OF 120W. SE CROSS-EQUATORIAL FLOW WILL CONVERGE
WITH THE NE TRADES TO KEEP CLUSTERS OF CONVECTION ACTIVE ALONG
THE ITCZ W OF 120W AS WELL. MEANWHILE ANOTHER PULSE OF NW SWELL
YIELDING COMBINED SEAS OF 10 FT AND GREATER WILL DOMINATE MOST
OF THE MARINE AREA W OF 115W TONIGHT THROUGH SAT.
E OF 115W...THE MAIN WEATHER PHENOMENA REMAINS THE PERSISTENT
CENTRAL AMERICA GAP WINDS. MORNING HIGH RESOLUTION SCATTEROMETER
DATA SHOWED NELY WINDS OF 20 TO 25 KT THROUGH THE GULF OF
PAPAGAYO...ENHANCED BY DRAINAGE EFFECTS... WITH 20 KT WINDS
NOTED OFF OF THE GULF OF FONSECA. BOTH OF THESE AREA ARE
EXPECTED TO CONTINUE WITH 20 KT OFFSHORE GAP WINDS...BUT ARE
LIKELY TO DIMINISH SLIGHTLY DURING THE DAYLIGHT HOURS. FRESH
TRADE WINDS WERE PUSHING FROM THE SW CARIBBEAN S ACROSS PANAMA
AS WELL...THROUGH THE GULF OF PANAMA TO THE ITCZ OFF THE
COLOMBIAN COAST...BUT ARE EXPECTED TO DIMINISH BELOW 20 KT
WITHIN 24 HOURS. MORNING SCATTEROMETER DATA ALSO SHOWED NLY FLOW
OF 20-25 KT PERSISTING TO FLOW S OUT THROUGH THE GULF OF
TEHUANTEPEC...BUT IS FORECAST TO DIMINISH BRIEFLY TONIGHT BEFORE
POST FRONTAL WINDS ACROSS THE W GULF OF MEXICO FLOW BEGIN TO
DRAIN THROUGH THE PASS AGAIN LATE SATURDAY.


forecast by STRIPLING