[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101130
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI NOV 10 2006

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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 51W S OF 15N MOVING W NEAR 15 KT. A BROAD
AREA OF LOW AND MID-LEVEL CYCLONIC TURNING IS EVIDENT IN
SATELLITE IMAGERY AND AN EARLIER QSCAT PASS. THIS WAVE CONTINUES
TO BE ACTIVE...ALTHOUGH CONVECTION HAS DECREASED OVERNIGHT AND
THIS MORNING...WITH SCATTERED MODERATE CONVECTION MAINLY AHEAD
OF THE WAVE AXIS FROM 4N-10N BETWEEN 53W-59W. WATER VAPOR
IMAGERY AND CIMSS DERIVED UPPER LEVEL WINDS SHOW 20-40 KT SELY
WINDS ACROSS THE WRN PORTION OF THE WAVE AND SIMILAR MAGNITUDE
SWLY WINDS ACROSS THE ERN PORTION. THESE WINDS ARE SHEARING MUCH
OF THE CONVECTION AND APPEAR TO HAVE DETACHED THE ONCE LARGE
AREA OF CONVECTION IN THE ITCZ. THIS WAVE WILL BE MOVING W INTO
A VERY DRY/STABLE ENVIRONMENT OVER THE NEXT COUPLE DAYS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 8N30W 8N42W 9N50W 6N57W.
BESIDES FOR THE CONVECTION ASSOCIATED WITH THE ACTIVE TROPICAL
WAVE...SCATTERED MODERATE IS WITHIN 180 NM EITHER SIDE OF THE
AXIS BETWEEN 33W-44W. SCATTERED MODERATE IS ALSO WITHIN 180 NM S
OF THE AXIS E OF 17W.

...DISCUSSION...
GULF OF MEXICO...
DEEP LAYERED RIDGING LIES ACROSS THE ERN GULF OF MEXICO AND
FLORIDA WITH VERY DRY STABLE AIR. THIS SINKING AIR ALOFT ALONG
WITH A 1015 MB SFC HIGH CENTERED NEAR 28N85W IS PRODUCING VERY
PLEASANT WEATHER AND LIGHT WINDS. THE CENTRAL AND WRN GULF IS
NOT QUITE AS CLEAR WITH DEBRIS TROPICAL MOISTURE FROM RECENTLY
DOWNGRADED T.D. ROSA SPREADING NORTHEASTWARD ACROSS THE WRN GULF
AROUND THE NRN PERIPHERY OF AN UPPER HIGH IN THE EPAC AND
PULLING NWD TOWARDS THE SE STATES BY A SHORTWAVE IN THE NW GULF.
HOWEVER...THIS MOISTURE IS MAINLY UPPER LEVEL WITH POSSIBLY A
FEW EMBEDDED ISOLATED SHOWERS AS SHOWN BY DOPPLER RADAR FROM
LOUISIANA. MOISTURE MAY THICKEN A LITTLE IN THE WRN/CNTRL GULF
AHEAD OF A COLD FRONT WHICH WILL LIKELY MOVE OFFSHORE FRI
NIGHT/SAT MORNING. THIS FRONT WILL NOT BE AS STRONG AS LAST FEW
IN THE REGION BUT IT WILL LIKELY INCREASE THE WINDS AND SEAS
SLIGHTLY THIS WEEKEND.

CARIBBEAN SEA...
THE CARIBBEAN IS MAINLY QUIET THIS MORNING WITH ONLY A FEW WEAK
FEATURES PRODUCING VERY LITTLE UNSETTLED WEATHER. THE TAIL END
OF AN ATLC FRONTAL BOUNDARY HAS STALLED FROM ERN CUBA ACROSS THE
CAYMAN ISLANDS TOWARDS THE COAST OF BELIZE. THIS PART OF THE
FRONT IS DISSIPATING WITH THE BOUNDARY MARKED ONLY BY A BROKEN
LINE OF LOW-MID LEVEL CLOUDS AND ISOLATED SHOWERS WITHIN 45 NM.
THE OTHER WEAK FEATURE IS A 1009 MB LOW LOCATED N OF PANAMA NEAR
11N79W. WHILE THIS SFC LOW REMAINS VERY WEAK WITH NO CONVECTION
OR EVEN THICK ORGANIZED CLOUDINESS...IT HAS BECOME MORE APPARENT
ON NIGHT CHANNEL IR IMAGES...QSCAT AND SFC OBS WHICH DO SHOW
CYCLONIC TURNING IN THE WINDS AND A LOW-LEVEL CLOUD SWIRL.
ISOLATED SHOWERS ARE WITHIN 300 NM N AND W OF THE WEAK LOW.
OTHERWISE...VERY DRY STABLE AIR ALOFT COVERS THE ENTIRE
CARIBBEAN SUPPORTED BY TWO UPPER-LEVEL HIGHS. ONE UPPER HIGH IS
LOCATED IN THE EPAC WITH RIDGING STRETCHING EASTWARD TO 75W. THE
OTHER IS LOCATED IN THE TROPICAL ATLC WITH RIDGING STRETCHING
WESTWARD TO 70W. A SLIGHT WEAKNESS EXISTS BETWEEN 70W-75W
INDUCED BY A PRONOUNCED TROUGH TO THE N. CONDITIONS ARE EXPECTED
TO REMAIN FAIRLY QUIET OVER THE NEXT DAY OR TWO WITH DRY
AIR/SINKING MOTION ALOFT REMAINING IN PLACE WHICH WILL CONTINUE
TO SUPPRESS CONVECTION.

ATLANTIC OCEAN...
A HIGHLY AMPLIFIED...SHORT WAVELENGTH MID/UPPER LEVEL PATTERN
LIES ACROSS THE ATLC BASIN. THE UPPER RIDGE THAT COVERED THE
GULF OF MEXICO AND CENTRAL U.S. HAS PUSHED EASTWARD NOW CENTERED
ALONG 78W. E OF THIS RIDGE LIES A NARROW TROUGH WHICH EXTENDS
FROM BERMUDA TO THE SE BAHAMAS. THIS TROUGH IS SHOWING SIGNS OF
WEAKENING AS IT MOVES ENE. THE ASSOCIATED SFC FRONTAL BOUNDARY
EXTENDS FROM 32N62W 24N71W TO ERN CUBA. SCATTERED SHOWERS ARE
WITHIN 240 NM E OF THE FRONT N OF 28N WITH ISOLATED SHOWERS
FOUND WITHIN 240 NM E OF THE FRONT S OF 28N. BEHIND THE
FRONT...VERY DRY AIR ALOFT...PATCHES OF FAIR WEATHER COOL AIR
STRATOCUMULUS AND BREEZY CONDITIONS ARE THE RULE. AN UPPER LEVEL
RIDGE EXISTS E OF THE TROUGH CENTERED NEAR 20N51W WITH RIDGING
COVERING THE AREA BETWEEN 40W-65W. SOME DEBRIS MOISTURE FROM THE
FRONT/TROUGH IS TRANSPORTED AROUND THE N PERIPHERY OF THE
RIDGE...N OF 26N. THIS HIGH LEVEL CLOUDINESS QUICKLY THINS OUT S
OF 26N DUE TO THE VERY DRY ENVIRONMENT ALOFT. A PRONOUNCED
TROUGH LIES E OF THIS RIDGE EXTENDING FROM AN UPPER LOW NEAR
30N34W SWD TO 20N32W THEN SHARPLY TO THE SW NEAR 15N47W. A
RELATED SFC LOW IS ANALYZED AT 1007 MB NEAR 29N34W WITH A
STATIONARY FRONT EXTENDING FROM THE LOW TO 24N36W THEN
DISSIPATING ALONG 20N45W 20N55W 23N58W. THERE IS LITTLE OR NO
CONVECTION ALONG THE FRONT. MOST OF THE SIGNIFICANT SHOWERS AND
TSTMS ARE E OF THE SFC LOW AND IN PARTICULAR WITHIN 120 NM OF A
PRE-FRONTAL TROUGH ALONG 32N27W 23N31W. THE ELONGATED UPPER
TROUGH HAS CONTRIBUTED TO THE FORMATION OF A TROPICAL JET WHICH
ORIGINATES NEAR THE BASE OF THE TROUGH AND EXTENDS NORTHEASTWARD
TOWARD THE CANARY ISLANDS. THIS JET IS LIKELY CONTRIBUTING
ENERGY WHICH IS ENHANCING A CONSIDERABLE AMOUNT OF CONVECTION IN
THE ITCZ AND NEAR THE TROPICAL WAVE ALONG 51W/52W. SOME OF THIS
MOISTURE...MAINLY HIGH LEVEL...IS BEING SPREAD TO THE NE BY THE
STRONG SWLY WINDS. AN UPPER HIGH REMAINS IN THE E TROPICAL ATLC
SE OF THE CAPE VERDE ISLANDS WITH A RIDGE EXTENDING N ALONG
18W/19W OVER THE MADEIRA/CANARY ISLANDS.

$$
CANGIALOSI




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