Tropical Storm Joaquin a Potential Long Term Threat to the Region Update One
WTNT41 KNHC 300254
TCDAT1
TROPICAL STORM JOAQUIN DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL112015
1100 PM EDT TUE SEP 29 2015
The cloud pattern of Joaquin has continued to become better
organized this evening. The low-level center is located within the
northwestern portion of the deep convection and the outflow has
continued to expand over the northern semicircle, which suggests
that the shear continues to decrease. The latest satellite
intensity estimates from TAFB and SAB are T3.5 or 55 kt on the
Dvorak scale. Based on the earlier reconnaissance aircraft data and
the continued increase in organization this evening, the initial
wind speed has been raised to 60 kt. Joaquin is forecast to be over
warm water and in an increasingly favorable upper-level wind pattern
during the next day or so. These conditions favor intensification
and the NHC forecast calls for Joaquin to become a hurricane within
the next 12 hours. The upper-level winds are shown by the global
models to become quite conducive for strengthening by 36 hours as an
upper-level anticyclone builds over the system, and additional
strengthening is anticipated. The new NHC forecast is a bit
higher than the previous advisory, and is close to the IVCN
intensity consensus aid. It should be noted, that the UKMET, GFS,
and ECMWF models all significantly deepen Joaquin during the next
few days, and the NHC forecast could be somewhat conservative.
Joaquin is moving west-southwestward at about 5 kt. This general
motion is forecast to continue during the next 24-36 hours while the
cyclone remains to the southwest of a weak mid-level ridge. During
this time, the center of Joaquin is forecast to move near or over
portions of the Central Bahamas. After 48 hours, a deepening mid-
to upper-level trough over the southeastern United States is
expected to cause a turn toward the north or north-northeast with an
increase in forward speed. There remains large spread in the
guidance at days 4 and 5, with the ECMWF showing a northeastward
motion toward Bermuda. Meanwhile, the 18Z GFS shifted significantly
westward and is close to the UKMET and HWRF, which are along the
western edge of the guidance envelope. The NHC track has been
shifted westward, but it is not as far west as the multi-model
consensus. The new track is fairly close to the ECMWF-Ensemble Mean.
The government of the Bahamas has issued a Hurricane Watch for the
Central Bahamas. Additional watches or warnings may be required
early Wednesday.
At this time it is very hard to gauge the long-range potential
impacts of Joaquin in the United States. The environmental steering
currents are complex and are not being handled in a consistent
manner by the forecast models. A wide range of outcomes are
possible and it is simply too soon to say what impacts, if any,
Joaquin will have on the United States.
FORECAST POSITIONS AND MAX WINDS
INIT 30/0300Z 25.8N 71.7W 60 KT 70 MPH
12H 30/1200Z 25.5N 72.4W 70 KT 80 MPH
24H 01/0000Z 25.2N 73.3W 75 KT 85 MPH
36H 01/1200Z 24.8N 74.1W 80 KT 90 MPH
48H 02/0000Z 24.9N 74.5W 85 KT 100 MPH
72H 03/0000Z 26.7N 74.0W 90 KT 105 MPH
96H 04/0000Z 31.3N 72.5W 85 KT 100 MPH
120H 05/0000Z 35.5N 72.0W 80 KT 90 MPH
$$
Forecaster Brown
000
FXUS61 KCAR 300319
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
1119 PM EDT TUE SEP 29 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE STATE TONIGHT. THIS FRONT WILL
COMBINE WITH A DEVELOPING SURFACE LOW OFF THE NEW ENGLAND COAST TO
BRING HEAVY RAIN TONIGHT THROUGH WEDNESDAY NIGHT. DRIER AND COOLER
WEATHER WILL RETURN ON THURSDAY AS GUSTY NORTHEAST WINDS DOMINATE
THE STATE.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
11:20 PM UPDATE: SURFACE COLD FRONT HAS MOVED THROUGH NORTHERN
MAINE AND TEMPS HAVE DROPPED INTO THE 50S SO LOWERED TEMPS EARLY
TONIGHT. ALSO INCREASED RAIN COVERAGE DOWNEAST. OTHERWISE, NO
MAJOR CHANGES THIS HOUR.
HEAVY RAIN SHIELD IS CURRENTLY DEVELOPING ACROSS VERMONT ON RADAR
AS SUB- TROPICAL MOISTURE STREAMS INTO THE STATE OF MAINE AHEAD OF
AN APPROACHING COLD FRONT. ALL GUIDANCE CAME INTO AGREEMENT WITH
ROBUST AMOUNTS OF RAINFALL EXPECTED TONIGHT THROUGHOUT THE DAY ON
WEDNESDAY. TRENDED MAXIMUM QPF AXIS FURTHER INLAND COMPARED TO
LAST FORECAST PACKAGE...AS ALL GUIDANCE HAS FRONT STALLING OUT
ACROSS INTERIOR DOWNEAST MAINE NOW. NAM12 IS THE MOST AGREESIVE
WITH UP TO 5 INCHES POSSIBLE NOW ACROSS THE CENTRAL HIGHLANDS.
WITH A SECONDARY MAXIMUM ACROSS INTERIOR DOWNEAST. OVERALL QPF
AMOUNTS LOOK VERY IMPRESSIVE FOR A 24 HOUR PERIOD WITH A GENERAL
3-5" AND SOME LOCALIZED HIGHER AMOUNTS COULD BE POSSIBLE. EVEN
THOUGH THINGS HAVE BEEN EXTREMELY DRY OVER THE PAST FEW
WEEKS...FELT THE AMOUNTS IN THEMSELVE WARRANT A FLOOD WATCH FOR
SMALL STREAM AND LOW LYING AREAS. ALL MODELS IN GOOD AGREEMENT ON
TOMORROWS SURFACE LOW TRACK WITH HEAVY RAIN OVERSPREADING THE
COAST AND DOWNEAST TOMORROW MORNING. GUIDANCE IS OVERALL IN GOOD
AGREEMENT NOW...SO CONFIDENCE HAS FINALLY INCREASED ON THE OVERALL
SOLUTION. BIGGEST IMPACT AND THREAT WILL BE LOCALIZED HEAVY
RAINFALL RATES WITH POSSIBLE BANDING STUCTURE DEVELOPMENT THAT
WILL LEAD TO LOCALZIED FLOODING.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
LOW PRESSURE WILL PASS THROUGH THE GULF OF MAINE WEDNESDAY NIGHT
THEN MOVE THROUGH THE MARITIMES DURING THE DAY THURSDAY. AT THE
SAME TIME STRONG HIGH PRESSURE IS EXPECTED TO BUILD IN FROM THE
NORTHWEST. A LOW PRESSURE TROUGH WILL REMAIN ACROSS THE GULF OF
MAINE FRIDAY CAUSING RAIN TO PERSIST ALONG THE COAST. HAVE USED A
50/50 BLEND OF THE GFS AND ECMWF TO GENERATE A MODEL CONSENSUS FOR
POP.. QPF AND SKY CONDITIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE LONG TERM REMAINS A CHALLENGING FORECAST, WITH CONSIDERABLE
UNCERTAINTY LINGERING AROUND THE FUTURE OF TS JOAQUIN. THE
FORECAST FOR JOAQUIN IS NO MORE CERTAIN TODAY COMPARED TO
YESTERDAY, WITH EVERY MODEL SEEMINGLY HAVING A DIFFERENT SOLUTION
BEYOND 48-72 HRS. THE DISCREPANCIES SEEM TO BE BASED ON THEIR
DIFFERENT HANDLING OF THE DIGGING UPPER TROF OVER THE ERN CONUS
AND UPPER RIDGE OVER THE NW ATLANTIC, TYPICAL OF UNCERTAINTY IN
THIS SORT OF A PATTERN. CURRENT SOLUTIONS RANGE FROM HOOKING INTO
THE CAROLINAS OR MID- ATLANTIC TO GOING OFF TO NOVA SCOTIA OR EVEN
EAST OF THERE.
WHAT DOES SEEM SOMEWHAT CERTAIN IS THAT THE FRONT WILL REMAIN
STALLED OFFSHORE AT THE START OF THE LONG TERM, AND MODELS SHOW
THE FRONT CREEPING BACK NORTH A BIT SATURDAY. THIS MAY ALLOW LKLY
POPS OFFSHORE AT THE START OF THE PERIOD TO NUDGE BACK NORTH
ONSHORE. FROM SATURDAY NIGHT ONWARD, HOWEVER, POPS WERE GENERALLY
KEPT AT CHC LEVELS, SINCE THE UNCERTAINTY IN THE LONG-TERM PATTERN
EVOLUTION AND THE FATE OF TS JOAQUIN SEEM TO PRECLUDE ANY
DEFINITIVE FORECAST FOR DRIER OR WETTER WEATHER ACROSS THE CWA.
&&
posted by Advackia at 8:32 PM
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