Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 12/02/11
AREA FORECAST DISCUSSION
NWS DENVER CO
231 PM MST WED NOV 30 2011
.SHORT TERM...MAIN CONCERN WILL BE UPCOMING WINTER STORM WITH
POSSIBLE SNOW AMOUNTS AND STRENGTH OF THE NORTHERLY WINDS. THE STORM
SYSTEM CAN BE SEEN DEVELOPING OVER THE GREAT BASIN AND IS DIGGING TO
THE SOUTH AND SOUTHEAST TOWARDS SOUTHERN NEVADA. LATEST RUC QG
HEIGHT TENDENCY FIELDS SHOWING THE BEST FALLS ACROSS SOUTHERN NEVADA
AND THIS TRENDS LOOKS TO CONTINUE TONIGHT UNTIL THE LOW BOTTOMS OUT
ACROSS THE CALIFORNIA AND ARIZONA THURSDAY MORNING. THIS TRACK WILL
TAKE THE STRONGEST UPWARD FORCING ACROSS UTAH WITH LESS FORCING AS
YOU MOVE EAST ACROSS COLORADO. SOME WEAK UPSLOPE ALREADY DEVELOPING
OVER EAST COLORADO WITH CYCLOGENESIS ACROSS SOUTHEAST COLORADO.
HOWEVER IT IS QUITE DRY IN THE LOW LEVELS WITH DEWPOINTS IN THE
SINGLE DIGITS AND TEENS AND WILL TAKE A WHILE TO MOISTEN UP. THE
MAIN PRESSURE RISE IS STILL OVER NORTHERN WYOMING SO THIS SHOULD
BRING THE MAIN FRONT INTO DENVER AROUND 03-04Z. BASED ON UPSTREAM
OBSERVATIONS THERE IS A 2-3 HOUR LAG OF THE SNOW STARTING BEHIND THE
FRONT. AIRMASS SHOULD BECOME SATURATED AROUND 09Z AT DENVER AND A
LITTLE LATER OVER OUR SOUTHERN BOUNDARIES AS UPSLOPE DEEPENS. THE
SNOW SHOULD CONTINUE MUCH OF THE DAY WITH A DECREASING TREND OVER
NORTHERN AREAS DURING THE AFTERNOON.
GIVEN LATEST MODEL OUTPUT...ADVISORY AMOUNTS LOOK IN ORDER OVER
MUCH OF THE CWA WHICH HAVE ALREADY BEEN UPDATED IN THE FORECASTS AND
STATEMENTS. SNOW AMOUNTS MAY BE LACKING ACROSS EASTERN ZONE 46 AND
47 ANY MAY BE MORE WIND THEN SNOW. GIVEN THE AMOUNT THIS STILL MAY
CREATE MORE WINDS THAN SNOW BUT STILL MAY CREATE SOME PROBLEMS WITH
SNOW AND WIND. LATEST NAM IS COME DOWN A BIT IN SNOW AMOUNTS A BIT
MORE INLINE WITH GFS/EUROPEAN OUTPUT OF 3-6 INCHES WITH THE HIGHER
AMOUNTS WEST AND SOUTH OF DENVER AND OVER HIGHER EAST SLOPES.
OVERALL THERE IS A SLIGHTLY SLOWER TREND IN SNOW DEVELOPING AND
DELAY THINGS JUST A BIT IN GRIDS.
.LONG TERM...STORM SYSTEM TO BE EXITING THE AREA THURSDAY EVENING
WITH IMPROVING CONDITIONS FROM ROUGHLY NORTH TO SOUTH. DID KEEP A
CHANCE OF LIGHT SNOW FOR MOST OF THE AREA WITH THE HIGHEST POPS
ALONG THE PALMER DIVIDE AND LINCOLN COUNTY. WEAK RIDGE STILL
EXPECTED FRIDAY ALTHOUGH AIRMASS WILL BE COLD. MODEL CROSS SECTIONS
INCREASE MOISTURE OVER THE MOUNTAINS DURING THE AFTERNOON AHEAD OF
THE NEXT WEATHER SYSTEM. SOME WEATHER AND POPS LOOK WARRANTED FOR AT
LEAST ZONE 31 AFTER 18Z. NAM PAINTS SOME LIGHT QPF AND SNOW
ACCUMULATIONS ACROSS THE FAR EASTERN ZONES WHILE THE OTHER MODELS
ARE DRY. WILL MAINTAIN THE DRY FORECAST FOR THE PLAINS. SNOW CHANCES
TO INCREASE ACROSS THE MOUNTAINS FRIDAY NIGHT...WITH PERHAPS A
SLIGHT CHANCE ACROSS THE LOWER ELEVATIONS. NAM AND GFS OFFER
DIFFERENT SOLUTIONS WITH THIS SYSTEM AS IT CROSS THE AREA SATURDAY.
THE GFS SHOWS MORE WIDESPREAD LIGHT SNOW AMOUNTS WHILE THE NAM
LIMITS THE AMOUNTS TO THE PALMER DIVIDE AS WELL AS THE FOOTHILLS AND
MOUNTAINS. GIVEN THE DISCREPENCIES...FEEL CHANCE POPS MOST AREAS
SEEM REASONABLE. BOTH MODELS DO SHOW SURFACE FRONT MOVING SOUTH
ACROSS THE AREA DURING THE MORNING. THIS STORM TO EXIT THE AREA BY
THE EVENING...WITH RIDGE BUILDING OVER THE GREAT BASIN AND NORTHWEST
FLOW ALOFT ACROSS COLORADO. MODELS CONTINUE TO HINT AT ANOTHER
DISTURBANCE MOVING SOUTHEAST ACROSS THE AREA SATURDAY NIGHT AND
MONDAY MORNING. THERE APPEARS TO BE ENOUGH LIFT AND MOISTURE TO KEEP
A SLIGHT CHANCE OF SNOW ACROSS THE AREA. OTHERWISE...A MAINLY DRY
NORTHWEST FLOW ALOFT TO PREVAIL THROUGH WEDNESDAY. WITH THE LACK OF
MOISTURE AND LIFT...TOOK OUT ALL MENTION OF MOUNTAIN SNOW MONDAY
AFTERNOON AND TUESDAY. MODELS HINT AT TROUGH MOVING ACROSS THE AREA
WEDNESDAY WITH AN INCREASE IN MOISTURE. ADDED SOME MOUNTAIN POPS
WITH DRY CONDITIONS ELSEWHERE. TEMPERATURES THROUGH THE EXTENDED TO
BE BELOW NORMAL...THOUGH SOME MODERATION ON EXPECTED ON TUESDAY.
&&
.AVIATION...A COLD FRONT WILL PASS THROUGH DENVER BETWEEN 03-04Z
GIVEN CURRENT TIMING OF FRONT NOW ACROSS NORTHERN WYOMING.
IT WILL TAKE A WHILE TO MOISTEN UP THE AIRMASS SO THERE WILL BE A
2-3 HOUR LAG FROM FROPA TO SNOWFALL AT LOCAL TERMINALS.
IFR AND ILS CONDITIONS EXPECTED TO DEVELOP BY 09Z WITH SNOW AND
BLOWING SNOW. CONDITIONS WILL SLOWLY IMPROVE DURING THURSDAY
AFTERNOON FROM NORTH TO SOUTH. BEST ESTIMATE OF STORM TOTAL SNOW AT
LOCAL TERMINALS IS 3-6 INCHES...WITH THE HIGHER AMOUNTS AT KAPA/KBJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 5 PM MST THURSDAY
FOR COZ033>037-039-040.
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 2 PM MST
THURSDAY FOR COZ038-042>044-048-049.
WINTER STORM WARNING FROM 11 PM THIS EVENING TO 5 PM MST
THURSDAY FOR COZ041-045>047.
&&
$$
SHORT TERM...SENTREKI
LONG TERM....D-L
AVIATION...S-E
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1208 AM EST WED NOV 30 2011
.SYNOPSIS...
LOW PRESSURE WILL TRACK DOWN THE SAINT LAWRENCE RIVER VALLEY
OVERNIGHT...WITH AN ASSOCIATED OCCLUDED FRONT CROSSING THE TRI-STATE
AS A RESULT. THE LOW THEN CONTINUES TO MOVE DOWN THE SAINT
LAWRENCE RIVER VALLEY INTO WEDNESDAY NIGHT. HIGH PRESSURE BUILDS
IN THURSDAY AND FRIDAY. A WEAK COLD FRONT WILL MOVE ACROSS THE
REGION FRIDAY NIGHT INTO SATURDAY WITH HIGH PRESSURE BUILDING BACK
INTO THE REGION FROM LATE SATURDAY THROUGH MONDAY. LOW PRESSURE
THEN APPROACHES THE AREA MONDAY THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AT 2Z OCCLUDED FRONT WAS JUST INTO FAR WESTERN ZONES...AND MAKING VERY
SLOW PROGRESS EASTWARD...AS A RESULT HAVE SLOWED DOWN TIMING FOR THE END
OF THE STEADIER RAINFALL. WITH ALL LIGHTNING WITH THIS SYSTEM SO
FAR CONFINED TO MI TO THE NNW OF UPPER LOW AND WELL OFF NJ COAST -
SE OF BUOY 44066...HAVE GONE AHEAD AND REMOVED THUNDER FROM
FORECAST. BASICALLY EXPECT TO SEE PERIODS OF MODERATE RAIN THROUGH
MOST OF THE NIGHT...TAPERING OFF FROM W TO E TOWARDS MORNING.
WITH SLOWER FRONTAL TIMING...HAVE ADJUSTED TEMPERATURE FALL OFF
OVER THE REGION SLOWER...WITH A BLEND OF NAM 2-METER/HRRR
TEMPERATURES...AND THE LATEST GUIDANCE - MET/MAV/LAV. FOR NOW IT
APPEARS FRONT WILL MOVE THROUGH BEFORE MIDNIGHT...SO MAX MIN
RECORDS SHOULD BE SAFE. HAVE INCLUDED THEM IN THE CLIMATE SECTION
OF THE AFD IN CASE THE FRONT MOVES SLOWER THAN EXPECTED - GOING
FAIRLY CLOSE TO 18Z-NAM/23Z HRRR TIMING RIGHT NOW.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
CLOSED LOW SHEARS NE FROM THE EASTERN GREAT LAKES ON WED THROUGH THE
ST LAWRENCE RIVER VALLEY WED NIGHT.
AFTER ANY LINGERING SHRA OVER FAR EASTERN ZONES EARLY WEDNESDAY
MORNING...REGION WILL REMAIN IN DRY SLOT ON WED AS SHORTWAVE ENERGY
SHEARS NE WHILE SLIDING TO THE COAST. THIS SHOULD MAINTAIN
GENERALLY DRY CONDITIONS...WITH SCT-BKN INSTABILITY CU. AN
ISOLATED SHOWER/SPRINKLE IS POSSIBLE ACROSS FAR NW SECTIONS...BUT
NOT ENOUGH COVERAGE TO WARRANT POPS. TEMPS WILL FEEL MORE FALL
LIKE WITH GUSTY WSW WINDS AND CAA FLOW HOLDING TEMPS IN THE LOWER
50 INTERIOR...MID 50S COAST. THIS IS STILL A FEW DEGREES ABOVE
NORMAL THOUGH.
SHEARING SHORTWAVE ENERGY AND WEAK SURFACE TROUGH MOVE ACROSS THE
REGION WED NIGHT. AGAIN THIS SHOULD BE A MAINLY DRY PASSAGE...WITH
GRADUALLY CLEARING SKIES IN ITS WAKE. GUSTY NW WINDS WILL CONTINUE
TO DROP TEMPS TO NEAR SEASONABLE...UPPER 30S CITY/COAST...UPPER
20S/LOWER 30S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH HIGH PRESSURE BUILDING IN FROM THE SOUTH AND
ZONAL FLOW ALOFT WITH LIGHT WINDS AND MOSTLY CLEAR SKIES.
TEMPERATURES WILL REMAIN NEAR NORMAL FOR THURSDAY AND FRIDAY. A
SHARP UPPER TROUGH SWEEPS THROUGH FRIDAY NIGHT WITH A WEAK COLD
FRONT. WITH DOWN SLOPING NORTHWEST WINDS AND LITTLE MOISTURE...NO
PRECIPITATION IS EXPECTED...JUST SOME MID LEVEL STRATO CU WITH THE
FRONT. A BRIEF SHOT OF COLD AIR WILL FOLLOW THIS FRONT WITH
TEMPERATURES SLIPPING A FEW DEGREES BELOW NORMAL ON SATURDAY.
HIGH PRESSURE BUILDS BACK IN FROM THE OHIO VALLEY THROUGH THE
WEEKEND WITH RIDGING ALOFT. TEMPERATURES RISE BACK TO NEAR NORMAL
SATURDAY AND SUNDAY WITH CIRRUS SPILLING OVER THE RIDGE.
NEXT POTENTIAL ISSUE WILL BE THE MON-WED TIME FRAME WITH GFS/ECMWF
BOTH HINTING AT A DEEP TROUGH DEVELOPING OVER THE MIDWEST AND A SFC
LOW DEVELOPING NEAR PA. BOTH SHOW PRECIPITATION IN THIS TIME FRAME
ASSOCIATED WITH THIS LOW PRESSURE AREA BUT KEPT POPS AT CHANCE
BECAUSE TIMING COULD CHANGE SIGNIFICANTLY IN THE NEXT FEW DAYS.
ECMWF THEN SHOWS THE UPPER LOW CUTTING OFF OVER NORTHERN NY AND A
SURFACE LOW DEEPENING OFF THE SOUTHERLY MAINE COAST WITH THE GFS
DEVELOPING THIS LOW MUCH FARTHER NORTH. DEPENDING ON THE EXACT TRACK
OF THIS SYSTEM...WINDS WILL PICK UP TUESDAY EVENING AND SNOW IS
POSSIBLE BEHIND THIS SYSTEM. TOO UNCERTAIN AT THIS POINT TO PUT MORE
THAN A CHANCE/SLIGHT CHANCE POPS FOR THIS SYSTEM.
TEMPS REMAIN NEAR NORMAL ON MONDAY AND DROP TO BELOW NORMAL ON
TUESDAY WITH LOWS NEAR TO BELOW FREEZING IN MOST AREAS TUESDAY NIGHT.
&&
.AVIATION /05Z WEDNESDAY THROUGH MONDAY/...
WINDS HAVE SHIFTED TO THE SOUTHWEST AS THE OCCLUDED FRONT CONTINUES
MOVING EAST OF CT AND LONG ISLAND. MOST CIGS AND VSBYS IMPROVED TO MVFR.
RAIN WILL END EAST OF NYC BETWEEN 06Z AND 08Z. MVFR CIGS AND VSBYS ARE
POSSIBLE DURING THIS TIME.
OTHERWISE...SW WINDS WILL RANGE FROM 15-20 KT WITH GUSTS OF 20-25 KT
AREA WIDE THROUGH THE DAY ON WEDNESDAY.
A WEAK COLD FRONT WILL CAUSE SW WINDS TO SHIFT TO THE NW AFTER SUNSET
WED AT SPEEDS BETWEEN 15 AND 20 KT AREA WIDE.
OUTLOOK FOR 00Z THURSDAY THROUGH MONDAY...
WED NIGHT: VFR. NW WINDS 15-20 KT WITH GUSTS 20-25 KT.
THU-MON...VFR.
&&
.MARINE...
SCA SE WINDS...WITH GUSTS UP TO 30 KT...EXPECTED AHEAD OF
OCCLUDED FRONT. SEAS EXPECTED TO CONTINUE BUILDING TO NEAR 7 TO
10 FT BY WEDNESDAY MORNING.
WINDS GRADUALLY SUBSIDE TO MARGINAL SCA BY WED MORNING AND CONTINUE
AS SUCH INTO WED NIGHT. OCEAN SEAS WILL ONLY SLOWLY SUBSIDE
THOUGH WITH THESE STRONG WINDS...LIKELY REMAINING SCA ON EASTERN
OCEAN WATERS...THROUGH WED NIGHT.
PERSISTENT WNW FLOW COULD MAINTAIN 5 FT SEAS INTO THURSDAY MORNING
WITH WINDS SUBSIDING AS HIGH PRESSURE BUILDS IN. WAVES WILL CONTINUE
TO DROP THROUGHOUT THE DAY THURSDAY AND REMAIN BELOW SCA CRITERIA.
WITH A COLD FRONT PASSAGE ON FRIDAY...SEAS ON THE EASTERN OCEAN
WATERS MAY PRODUCE SCA SEAS WHICH WILL LIKELY PERSIST THROUGH
SATURDAY. HIGH PRESSURE BUILDS IN ON SUNDAY WITH SEAS AND WINDS
BELOW SCA CRITERIA.
&&
.HYDROLOGY...
EXPECTING GENERALLY 1/2" TO 3/4" THROUGH TONIGHT...WITH LOCALLY
HIGHER AMOUNTS COINCIDENT WITH BANDING LOCATION. ONLY LOCALIZED
MINOR URBAN AND POOR DRAINAGE FLOODING EXPECTED.
&&
.CLIMATE...
RECORD HIGHEST MINIMUM TEMPERATURES (MAX MINS)
FOR TODAY - NOVEMBER 29TH
RECORD YEAR
CENTRAL PARK 58 2005
LAGUARDIA 60 2005
KENNEDY 56 2005
NEWARK 57 2005
ISLIP 57 2005
BRIDGEPORT 52 2005
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330-
335-338-340-345-350-353-355.
&&
$$
SYNOPSIS...LN/NV
NEAR TERM...MALOIT
SHORT TERM...MALOIT/NV
LONG TERM...LN
AVIATION...GC
MARINE...MALOIT/LN/NV
HYDROLOGY...NV
CLIMATE...
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
205 PM EST Wed Nov 30 2011
.SYNOPSIS...
As an occluding surface low moves northeast up the St. Lawrence
Seaway, and a cold front pushes well off the east coast, surface
high pressure is building into the northern Gulf Coast. Around the
noon hour, the surface ridge extended from eastern Texas up into the
western Great Lakes. Temperatures across most of the Gulf Coast
States were in the 40s and 50s, with the coldest readings to the
north, and this was about 10 to 20 degrees below normal. Meanwhile,
water vapor loops indicate a mid-upper level shortwave trough over
Mississippi and Alabama located at the base of the broader longwave
trough along the east coast of the United States. This shortwave
will continue to dig southeast and reach the Atlantic coast by this
evening. Strong subsidence and drier air will arrive behind the
departing shortwave.
&&
.NEAR TERM (Rest of Today and Tonight)...
The focus for the first 18 hours of the forecast was on temperature
trends for tonight, and related frost and freeze concerns. Low
stratus continues to erode early this afternoon, albeit much more
slowly than the models have been willing to indicate. The HRRR has a
very good handle on the current distribution of clouds and it slowly
eats away at the edges of the stratus from near MAI up into eastern
Alabama through the rest of the afternoon. One thing that the HRRR
is an outlier on is showing the remnants of the stratus deck
settling closer to the surface in the evening, and then starting to
expand back into the northwest parts of our forecast area. This is a
possibility, especially with a strengthening subsidence inversion in
the wake of the departing shortwave possibly "trapping the moist
layer" beneath the inversion. However, with no support from other
models we basically extrapolated the current cloud trends to get
mostly clear skies by 06z. If the HRRR ends up being the most
realistic with respect to overnight cloud cover, that would have a
notable impact on low temperatures (keeping things warmer, and
reducing risk of frost).
Since we were operating on the assumption of mostly clear skies, and
with the surface high pressure building in, it would be a good night
for radiational cooling. 12z soundings from KLIX and KJAN to the
west showed a sharp and shallow radiation inversion, and that would
likely be the scenario given clear skies and calm winds. Therefore,
the lows were not changed much from the previous forecast and fall
between 30 and 32 degrees. This is similar to what was observed
upstream in S/C Mississippi this morning, where dewpoints the
preceding afternoon and evening were also in the mid-30s. Therefore,
strong radiational cooling is expected to compensate for dewpoints
initially above freezing. Exceptions to the low temperature forecast
would be upper 20s in the typical cold spots: west of Dothan and the
Choctawhatchee River, the Apalachicola National Forest, the Suwannee
River Valley, and parts of the Chattahoochee River Valley. Thus, we
upgraded the Freeze Watch to a Freeze Warning for all of the area
except for coastal zones from Gulf County around the Big Bend to the
mouth of the Suwannee River (lows forecast in the mid 30s). Frost
was added to the grids as well with the cold temperatures, light
winds, and RH approaching 100% by 12z. We could see a little light
fog, but the visibilities upstream were only about 5-6 miles this
morning in Mississippi, and we are expecting a similar situation
around here. For Tallahassee: forecast lows in the center of the
city are 36-37 degrees, compared to 30 at the airport.
&&
.SHORT TERM (Thursday through Friday Night)...
A quiet weather pattern is in store for the short term period. Clear
skies and highs climbing into the lower to middle 60s regionwide are
expected.
The main forecast challenge is forecasting overnight lows Thursday
night. Although Thursday night is forecast to be warmer than
Wednesday night, the threat still exists for some patchy frost
development near dawn. Expect lows to fall into the middle 30s with
our cooler spots falling into the lower 30s. It is the cooler spots
that will also have the greatest chance for patchy frost
development.
High temperatures will continue to warm on Friday with middle to
upper 60s expected. Overnight lows will moderate into the upper 30s
to lower 40s inland, with upper 40s likely along the coast.
&&
.LONG TERM (Saturday through next Wednesday)...
The extended period will begin with an amplified upper pattern
across the CONUS, consisting of a deep trough and cut-off low over
the four corners region, and a building ridge stretching from the
Gulf of Mexico up the eastern seaboard. The system over the
southwestern states will slowly progress eastward through the period
and bring a front into the deep south by late Monday into Tuesday,
ushering in a shot of cold air for the middle of next week.
Ahead of this system, dry conditions and moderating temperatures are
expected across the forecast area, with easterly flow on Saturday,
becoming onshore by late Sunday into Monday. Temperatures are
forecast to be at, or just slightly above, normal through the
weekend.
A band of showers is expected to accompany the front into the region
beginning Monday and continuing through Monday night. At this time,
it appears the main energy with the system will be shunted northward
by the pre-existing upper ridge, causing the rain to diminish as the
front crosses the forecast area. Instability is forecast to be
minimal or non-existent with no thunderstorms expected.
&&
.MARINE...
With the calm center of the surface ridge sprawling the southeastern
part of the country expected to pass well north of our forecast
area, winds and seas will refrain from subsiding too much over the
next several days. In fact, as the ridge continues to move east, our
forecast waters will fall under a more easterly flow regime. This
regime is favorable for nocturnal east to west surges in both winds
and seas. These surges will begin Thursday night and continue
through the first part of the weekend, gradually getting stronger
each night. Winds, and possibly seas, reach cautionary levels by
Friday night and could require an advisory by Saturday night.
&&
.AVIATION...
Low stratus took longer to erode this morning than models had
originally forecast. In fact, alternate fuel impacts (1600 ft CIG)
are still occurring at DHN, with the low ceilings scattered out at
the remainder of the four terminals. The HRRR model represented the
current cloud cover well, so that was used to time the low clouds
through 00z. With a surface ridge settling into the region tonight,
the winds should become calm (or nearly calm) at all of the
terminals. We expect a similar evolution to what happened upstream
in Mississippi this morning, when light fog (5-6SM visibility)
developed after midnight. We kept things in the VFR range for now,
but all of the terminals include a "6SM BR" group towards dawn.
&&
.FIRE WEATHER...
Although minimum RH will fall to between 30-35% over much of the
area tomorrow afternoon, no other criteria are expected to be met
for red flag conditions in our Florida zones. Dispersions may
approach 70 in the eastern Big Bend, but this is coincident with the
area of highest forecast RH. The minimum RH falls slightly again
into Friday, but with light winds no red flag conditions are
expected. More east-southeasterly flow this weekend will finally
increase low level humidity.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 30 64 34 68 41 / 0 0 0 0 0
Panama City 33 63 42 67 47 / 0 0 0 0 0
Dothan 31 62 36 66 39 / 0 0 0 0 0
Albany 30 63 33 66 38 / 0 0 0 0 0
Valdosta 31 64 35 67 42 / 0 0 0 0 0
Cross City 31 68 38 72 44 / 0 0 0 0 0
Apalachicola 35 62 43 66 48 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Freeze Warning from 2 AM to 8 AM CST Thursday for Coffee-Dale-
Geneva-Henry-Houston.
GA...Freeze Warning from 3 AM to 9 AM EST Thursday for Baker-Ben Hill-
Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-Dougherty-
Early-Grady-Irwin-Lanier-Lee-Lowndes-Miller-Mitchell-
Quitman-Randolph-Seminole-Terrell-Thomas-Tift-Turner-Worth.
FL...Freeze Warning from 3 AM EST /2 AM CST/ to 9 AM EST /8 AM CST/
Thursday for Calhoun-Central Walton-Coastal Bay-Gadsden-
Holmes-Inland Bay-Inland Dixie-Inland Franklin-Inland Gulf-
Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton-
Jackson-Lafayette-Leon-Liberty-Madison-South Walton-
Washington.
GM...None.
&&
$$
Long Term...Camp
Short Term/Marine...Harrigan
Synopsis/Near Term/Aviation/Fire Weather...Lamers
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
310 AM EST Wed Nov 30 2011
...UPDATED AVIATION SECTION FOR 12UTC TAF ISSUANCE...
.SYNOPSIS...
07Z water vapor and H4 RUC analysis shows an active upper level
pattern across the CONUS this morning. Large upper level low that
has been influencing our weather the past few days is now quickly
lifting out to the northeast and taking its mid-level cold pool with
it. On the backside of this upper low, a shortwave impulse is
dropping southeastward over the middle MS valley/Southern Plains.
This impulse will amplify as it slide along the northern Gulf coast
during the next 24 hours, and although it looks impressive later
today on forecast upper level charts, the atmosphere will simply be
too dry for this energy to have any significant impact on our
sensible weather. Finally, looking far to the west we find a potent
upper level trough arriving over the Pacific Northwest coast. This
energy is progged by global guidance to cut off and stall as it
reaches the southern California coast.
Low levels/surface,
1025mb high pressure is centered over the southern Plains this
morning. An extension of this ridge reaches eastward all the way to
our forecast area. Vast area of lower stratus under the residual
cold pool from the departing upper low covers much of AL/GA and into
the FL panhandle this morning. These clouds combined with a bit of
wind are helping to keep temps up generally in the 40s. Locations
ahead of this band of clouds from KVLD south into the eastern FL big
bend will likely be able to drop into the mid/upper 30s before
sunrise.
&&
.SHORT TERM (Today through Friday)...
Today,
Surface high pressure will move east from the Southern Plains toward
the region. At the same time, shortwave energy aloft will approach
and slide over the region by this evening. Main forecast concern
this morning will be the evolution/dissipation of the stratus deck
over portions of the area. The retreat of the cold pool aloft should
promote the dissipation of this cloud deck through the morning
hours. 00Z NAM and 06Z local hi-res WRF-ARW are handling the initial
position of these clouds best, and will follow a blend of these
models for morning movement and timing of dissipation in the grids.
Both models show rapid dissipation of this deck after 15Z...and will
remove all low level stratus over the landmass by early afternoon.
Amplifying mid/upper level shortwave and associated jet streak will
overspread the area later today. Decent zone of synoptic support/QG
forcing head of the shortwave along with associated jet dynamics may
bring a few bands of upper level cirrus overhead during the
afternoon/evening...however these should be thin and will keep a
mostly sunny forecast for the afternoon hours. The lower/mid levels
will be very dry as well by this afternoon...and despite the
overspread synoptic lift, rain chances will be near zero.
Temperatures will be quite cool once again as the near solar
minimum keep diurnal mixing on the weak side. Generally looking for
high temps in the middle 50s to perhaps around 60 degrees.
Tonight,
A cold night in store. Freeze watches are being hoisted for all
zones during the late night/early morning hours of Thursday.
Shortwave and any associated upper level cirrus will be exiting to
our east by later this evening allow for clear skies. Surface high
is not in an ideal position, but feel it will be close enough to
allow areas of boundary layer decoupling late tonight. Once this
decoupling allows winds to go calm, these light winds combined with
the very dry low levels will create excellent radiational cooling
conditions, and temperatures will drop quickly. Currently expecting
many locations away from the immediate coast, and away from more
urbanized areas to reach or drop a few degrees below freezing.
Normally colder sheltered/inland spots may briefly reach the upper
20s by sunrise. Once again...locations along the immediate coast and
in urbanized spots (such as downtown Tallahassee) are likely to
remain a few degrees above freezing. However, even for these
locations, temps reaching the middle 30s will still support frost
development.
Thursday through Friday,
Stacked ridging will bring pleasant, dry, and seasonable conditions
to the region through the end of the work week. The daylight hours
of Thursday will feature plenty of sunshine and temperatures rising
from the cold early morning readings toward the lower/mid 60s by mid
afternoon. Thursday night will again be cool, but currently not
anticipating any widespread freezing temperatures. As the ridge
center to our north begins to move eastward, low level flow will
come around more to the NE/E and begin to transport a slow increase
in Atlantic moisture toward the region. With this in mind, the best
chances of seeing temps approach 32 Thursday night will be across
our northern/western zones. Friday is shaping up to be quite a
pleasant day, with plenty of sunshine and temperatures up another
several degrees from Thursday.
&&
.LONG TERM (Saturday through next Wednesday)...
The extended period will begin with an amplified upper pattern
across the CONUS, consisting of a deep trough and cut-off low over
the four corners region, and a building ridge stretching from the
Gulf of Mexico up the eastern seaboard. The system over the
southwestern states will slowly progress eastward through the period
and bring a front into the deep south by late Monday into Tuesday,
ushering in a shot of cold air for the middle of next week.
Ahead of this system, dry conditions and moderating temperatures are
expected across the forecast area, with easterly flow on Saturday,
becoming onshore by late Sunday into Monday. Temperatures are
forecast to be at, or just slightly above, normal through the
weekend.
A band of showers is expected to accompany the front into the region
beginning Monday and continuing through Monday night. At this time,
it appears the main energy with the system will be shunted northward
by the pre-existing upper ridge, causing the rain to diminish as the
front crosses the forecast area. Instability is forecast to be
minimal or non-existent with no thunderstorms expected.
&&
.MARINE...
Offshore flow will continue through today on the eastern periphery
of approaching surface high pressure. Although winds are now
generally below advisory levels, seas have been slow to subside over
the offshore waters and will extend the advisory for these legs
through the morning hours. Surface high pressure will slowly pass to
our north through the end of the week allowing winds to come around
to the Northeast and eventually east. With the easterly flow,
periods of cautionary conditions are likely to develop each
overnight period. The next front is not expected to approach the
forecast waters until the early portion of next week.
&&
.AVIATION (Through 12Z Thursday)...Stratus deck has crept a bit
further south than previously anticipated, with MVFR and Alternate
Fuel CIGS impacting all area terminals. This deck should finally
break up and dissipate during the morning hours, with VFR conditions
expected thereafter.
&&
.FIRE WEATHER...
A cool and dry airmass will be in place across the region through
the next two days. However, relative humidity values are forecast to
remain just above critical values. Therefore, no Red Flag conditions
are expected attm.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 58 31 64 36 70 / 0 0 0 0 0
Panama City 58 35 62 44 68 / 0 0 0 0 0
Dothan 57 31 62 36 66 / 0 0 0 0 0
Albany 57 30 63 33 68 / 0 0 0 0 0
Valdosta 58 32 64 35 69 / 0 0 0 0 0
Cross City 61 32 68 38 72 / 0 0 0 0 0
Apalachicola 59 36 62 44 66 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Freeze Watch from late tonight through Thursday morning for
Coffee-Dale-Geneva-Henry-Houston.
GA...Freeze Watch from late tonight through Thursday morning for
Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-
Decatur-Dougherty-Early-Grady-Irwin-Lanier-Lee-Lowndes-
Miller-Mitchell-Quitman-Randolph-Seminole-Terrell-Thomas-
Tift-Turner-Worth.
FL...Freeze Watch from late tonight through Thursday morning for
Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal
Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-
Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Dixie-
Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-
Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-Liberty-
Madison-South Walton-Washington.
GM...Small Craft Advisory until 11 AM EST this morning for Waters
from Suwannee River to Apalachicola FL from 20 to 60 NM-
Waters from Apalachicola to Destin FL from 20 to 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...CAMP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 AM CST WED NOV 30 2011
.DISCUSSION...
840 PM CST
HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST THIS EVENING TO TWEAK
FOR CURRENT TRENDS. WINDS CONTINUE TO DIMINISH ACROSS ILLINOIS AS
THE TIGHTER PRESSURE GRADIENT SHIFTS TO THE EAST AS THE LOW MOVES
OVER LAKE ERIE. WIND DIRECTION HAS SHIFTED SLIGHTLY WEST OF NORTH
WHICH HAS ALLOWED MORE OF AN OFFSHORE WIND TO SET UP ALONG THE
ILLINOIS SHORE RESULTING IN WINDS FALLING BELOW ADVISORY CRITERIA.
WINDS OVER THE WATER REMAIN STRONG WITH GUSTS INTO THE 35-45 KT
RANGE WHICH CONTINUE TO MOVE ONSHORE ACROSS NORTHWEST INDIANA.
SOME GUSTS TO 35-40 KT MAY ALSO BE AFFECTING THE FAR SOUTHERN COOK
COUNTY LAKESHORE BUT THIS SHOULD BE INFREQUENT. FORECAST SOUNDINGS
SHOW THAT WINDS OFF THE DECK WILL QUICKLY DIMINISH ACROSS NW
INDIANA TO THE POINT WHERE ADVISORY LEVEL SPEEDS WOULD NOT BE
SUPPORTED TOWARDS 06-07Z. GIVEN THIS AND THE STRONGER WINDS
CONTINUING ACROSS LAKE AND PORTER COUNTY INDIANA AT THIS HOUR HAVE
EXTENDED THE WIND ADVISORY UNTIL 07Z. OTHERWISE SKIES CONTINUE TO
CLEAR FROM THE WEST ALLOWING TEMPS JUST WEST OF THE CWA TO FALL
INTO THE UPPER 20S WITH SIMILAR READINGS NOT FAR BEHIND FOR THE
WESTERN CWA. GOING FORECAST LOWS STILL LOOK ON TRACK.
MDB
//PREV DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* NONE
KJB
//DISCUSSION...UPDATED 06Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT
CONTINUES TO RELAX AND MOST GUSTS ACROSS THE REGION HAVE
ENDED...WITH THE EXCEPTION OF THE EASTERN TERMINALS...ORD/MDW
OCCNLY GUST TO 20 KT...AND THAT SHOULD LIKELY CONTINUE FOR A FEW
MORE HOURS BEFORE COMPLETELY STOPPING. GYY WILL CONTINUE TO GUST
STRONGER IN THE 35 KT RANGE OUT THE GATE. THOSE WINDS SHOULD
SLOWLY ABATE OVERNIGHT AS HIGH PRESSURE SWINGS IN FROM THE PLAINS
AND FLIPS FLOW NW...W...AND EVENTUALLY AROUND TO THE SW. CIGS WILL
CONTINUE TO CLEAR FROM W TO E TONIGHT...WITH THE WESTERN FLANK OF
CLOUDS THAT ARE OVERHEAD AND SHIFT EAST...STRETCHING FROM JUST
EAST OF JVL TO ARR AND SOUTH TO IKK. GENERALLY CLEAR SKIES AND
LIGHT WINDS ANTICIPATED FOR THE PRESENT TAFOR.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR...CHC -SN...MVFR LATE
* FRIDAY...VFR
* SATURDAY...SLT CHC RA...RASN...MVFR POSSIBLE
* SUNDAY...CHC SN...MVFR POSSIBLE
* MONDAY...VFR
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ014 UNTIL 2 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 5 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-LMZ874-
LMZ876-LMZ878 UNTIL 5 AM WEDNESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL NOON WEDNESDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 2 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1051 PM CST TUE NOV 29 2011
.DISCUSSION...
840 PM CST
HAVE MADE A FEW ADJUSTMENTS TO THE FORECAST THIS EVENING TO TWEAK
FOR CURRENT TRENDS. WINDS CONTINUE TO DIMINISH ACROSS ILLINOIS AS
THE TIGHTER PRESSURE GRADIENT SHIFTS TO THE EAST AS THE LOW MOVES
OVER LAKE ERIE. WIND DIRECTION HAS SHIFTED SLIGHTLY WEST OF NORTH
WHICH HAS ALLOWED MORE OF AN OFFSHORE WIND TO SET UP ALONG THE
ILLINOIS SHORE RESULTING IN WINDS FALLING BELOW ADVISORY CRITERIA.
WINDS OVER THE WATER REMAIN STRONG WITH GUSTS INTO THE 35-45 KT
RANGE WHICH CONTINUE TO MOVE ONSHORE ACROSS NORTHWEST INDIANA.
SOME GUSTS TO 35-40 KT MAY ALSO BE AFFECTING THE FAR SOUTHERN COOK
COUNTY LAKESHORE BUT THIS SHOULD BE INFREQUENT. FORECAST SOUNDINGS
SHOW THAT WINDS OFF THE DECK WILL QUICKLY DIMINISH ACROSS NW
INDIANA TO THE POINT WHERE ADVISORY LEVEL SPEEDS WOULD NOT BE
SUPPORTED TOWARDS 06-07Z. GIVEN THIS AND THE STRONGER WINDS
CONTINUING ACROSS LAKE AND PORTER COUNTY INDIANA AT THIS HOUR HAVE
EXTENDED THE WIND ADVISORY UNTIL 07Z. OTHERWISE SKIES CONTINUE TO
CLEAR FROM THE WEST ALLOWING TEMPS JUST WEST OF THE CWA TO FALL
INTO THE UPPER 20S WITH SIMILAR READINGS NOT FAR BEHIND FOR THE
WESTERN CWA. GOING FORECAST LOWS STILL LOOK ON TRACK.
MDB
//PREV DISCUSSION...
313 PM CST
MESOSCALE/TONIGHT...
A VERY IMPRESSIVE WATER VAPOR SATELLITE LOOP THIS AFTERNOON
REVEALS THE EXPANSIVE COLD CORE LOW LIFTING NORTHEAST ACROSS THE
APPALACHIANS...JUST GRAZING THE AREA. A WELL-DEFINED DEFORMATION
AREA HAS FILLED IN WITH BANDS OF COLDER AND AT TIMES CONVECTIVE
CLOUD TOPS PROVIDING HEAVIER AND FROZEN PRECIPITATION ACROSS PARTS
OF NORTHERN IN. THE DUAL POLARIZATION RADAR EVEN DETECTED THE
PRECIPITATION TYPE SWITCH AT 7000-9000 FT. THIS HAS BEEN OBSERVED
AT THE GROUND JUST TO THE SOUTH AND EAST OF THE FORECAST AREA IN
LAFAYETTE /WHERE SLUSHY ACCUMULATION HAS OCCURRED ON GRASSY
SURFACES/. THE 13KM RUC SOUNDINGS ACROSS BENTON AND JASPER
COUNTIES CONTINUE TO SHOW A GRADUAL SHRINKING OF THE NEAR-SURFACE
WARM LAYER TO ALLOW FOR A MIX TO MAKE IT TO THE GROUND FOR
POSSIBLY A COUPLE HOURS. THAT COUPLE OF HOURS LOOKS TO BE IT GIVEN
SATELLITE AND SHORT TERM MODEL TRENDS TO SHIFT THE FORCING EAST.
GIVEN THAT ANY TRANSITION WILL BE SO SHORT LIVED AND OVER WARM
GROUND...WILL CANCEL THE WINTER WEATHER ADVISORY.
STRONG NORTHERLY WINDS HAVING GUSTED AS HIGH AS 60 MPH AT THE
CHICAGO CRIB...52 MPH AT GARY...AND 48 MPH AT MIDWAY WILL
GRADUALLY DIMINISH THROUGH THE EVENING WITH THE AREA PINCHED
BETWEEN THE 1001 MB LOW NEAR CLEVELAND AND THE INCOMING 1027 MB
RIDGE. AN AIRCRAFT SOUNDING OUT OF OHARE JUST AFTER 2 PM REVEALED
40 KT WINDS AT THE TOP OF THE CHANNEL...AND NAM AND RUC SOUNDINGS
KEEP SIMILAR SPEEDS WITHIN THE BOUNDARY LAYER UNTIL A COUPLE HOURS
AFTER SUNSET. WITH STILL AN ONSHORE COMPONENT TO THE WIND...WILL
LET THE WIND ADVISORY CONTINUE. A QUICK DECOUPLING LATER IN THE
EVENING SHOULD ALLOW FOR WINDS TO COME DOWN MORE RAPIDLY ACROSS
THE ILLINOIS FORECAST AREA. ASSOCIATED LAKE SHORE FLOODING
CONCERNS WITH THE WIND ALSO CONTINUE GIVEN THE 10 TO 15 FT WAVES
FORECAST...BUT LIKELY WILL NOT LAST AS FAR INTO WEDNESDAY. CLOUDS
SHOULD SCOUR FAIRLY QUICKLY WEST OF CHICAGO THROUGH EARLY
EVENING...THEN MORE SLOWLY DOWNSTREAM OF THE LAKE. WHILE SOME LAKE
ENHANCED CLOUDS MAY OCCUR...FORECAST DEPTHS ARE VERY SHALLOW WITH
DRIER AIR BEING RAKED IN ON THE NORTHERLY WINDS...AND THUS NOT
EXPECTING ANY SHOWERS. WITH FORECAST TEMPERATURES HAVE MADE ONLY
MINOR TWEAKS...WITH READINGS ALMOST RIGHT AT NORMAL ACROSS THE
ENTIRE FORECAST AREA.
MTF
WEDNESDAY THROUGH TUESDAY...
ACTUALLY LOOKING LIKE A DAY OR TWO OF FAIRLY PLEASANT LATE NOVEMBER
WEATHER WEDNESDAY INTO THURSDAY IN WAKE OF TODAY`S SIDESWIPING BY
THE STRONG STORM SYSTEM. WARM AIR ADVECTION WILL COMMENCE WEDNESDAY
AS LOW/MID LEVEL FLOW BEGINS TO BACK IN ADVANCE OF THE NEXT NORTHERN
STREAM SHORTWAVE WHICH WILL BEGIN DROPPING INTO THE NORTHERN PLAINS.
AFTER A CHILLY MORNING TEMPS SHOULD REBOUND NICELY TOMORROW WITH
NEARLY FULL SUNSHINE.
INCREASING MID/HIGH LEVEL CLOUDINESS AND SOUTHWEST WINDS SHOULD KEEP
TEMPS A BIT WARMER TOMORROW NIGHT WHICH WILL THEN PROVIDE FOR A NICE
SPRING BOARD FOR TEMPS THURSDAY TO CLIMB BACK TO SEVERAL DEGREES
ABOVE AVERAGE. COLD FRONT WILL THEN DROP SOUTHWARD ACROSS THE CWA
LATE THURSDAY AFTERNOON/EARLY THURSDAY EVENING. STRONGEST FORCING
WITH THIS WAVE LOOKS TO PASS WELL NORTH/NORTHEAST OF THE AREA AND
WITH SCANT MOISTURE AT BEST AM HAVING A HARD TIME GETTING TOO WORKED
UP OVER OUR SNOW CHANCES THURSDAY NIGHT. ECMWF/GFS BOTH STILL TRYING
TO SPIT OUT A HUNDREDTH OF AN INCH OR SO OF QPF SO HAVE MAINTAINED
THE SLIGHT CHANCE POPS WE HAD GOING...WHICH ARE SUPPORTED BY CURRENT
MOS NUMBERS.
VERY QUICK HITTING SHOT OF FAIRLY COLD AIR THEN ARRIVES LATER
THURSDAY NIGHT AND ESPECIALLY FRIDAY. THERE STILL DOES APPEAR TO BE
A SMALL WINDOW OF OPPORTUNITY FOR SOME LAKE EFFECT SNOW SHOWERS IN
PORTER COUNTY LATE THURSDAY NIGHT INTO FRIDAY MORNING...BUT NOT
EXPECTING ANYTHING SIGNIFICANT WITH LAKE EFFECT PARAMETERS FAIRLY
MARGINAL AND DURATION BEING SHORT AS FLOW QUICKLY BACKS TO
SOUTHERLY FRIDAY AFTERNOON.
BY THIS WEEKEND OUR ATTENTION WILL TURN THE THE VIGOROUS UPPER LOW
THATS CURRENTLY OFF THE BRITISH COLUMBIA COAST. MEDIUM RANGE
GUIDANCE IS IN REMARKABLY GOOD AGREEMENT THROUGH FRIDAY WITH THIS
SYSTEM DROPPING SOUTH AND WITH AN ANOMALOUSLY STRONG UPPER LOW (H5
HEIGHTS 3+ STANDARD DEVIATIONS BELOW AVERAGE) SETTING UP SHOP OVER
THE DESSERT SOUTHWEST BY FRIDAY. MODERATE RIDGING DOWNSTREAM OVER
THE SOUTHEASTERN CONUS SHOULD LEAVE OUR AREA IN A WEST-SOUTHWEST
FLOW ALOFT.
FORECAST CONFIDENCE THIS WEEKEND INTO EARLY NEXT WEEK IS LOW AS
MODELS OFTEN STRUGGLE WITH CUT OFF LOWS. HAVING SAID THAT...IT
APPEARS AS THOUGH THIS FIRST UPPER LOW WILL WEAKEN INTO AN OPEN WAVE
AND RIDE THE SOUTHWEST FLOW ALOFT INTO OUR AREA THIS WEEKEND...WITH
SOME DEGREE OF PHASING WITH A RESULTANT AMPLIFYING NORTHERN
STREAM TROUGH EXPECTED. WHILE DETAILS ARE MURKY...IT WOULD APPEAR
THAT OUR AREA IS IN STORE FOR INCREASINGLY UNSETTLED WEATHER LATE
SATURDAY INTO SUNDAY. WITH VARYING SOLUTIONS ABOUT THE TRACK OF
THE SURFACE SYSTEM AND RESULTANT THERMAL PROFILES IT WOULD BE
ABSURD TRYING TO PINPOINT P-TYPES FOR THE WEEKEND JUST YET.
ANOTHER...POTENTIALLY MORE SIGNIFICANT BUT BRIEF BLAST OF COLD AIR
LOOKS TO ARRIVE IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NO CONCERNS OVERNIGHT
SHEA
//DISCUSSION...UPDATED 06Z...
WINDS CONTINUE TO TAPER OFF THIS EVENING AS A STRONG LOW PRESSURE
SYSTEM MOVES OUT OF THE REGION. SURFACE PRESSURE GRADIENT
CONTINUES TO RELAX AND MOST GUSTS ACROSS THE REGION HAVE
ENDED...WITH THE EXCEPTION OF THE EASTERN TERMINALS...ORD/MDW
OCCNLY GUST TO 20 KT...AND THAT SHOULD LIKELY CONTINUE FOR A FEW
MORE HOURS BEFORE COMPLETELY STOPPING. GYY WILL CONTINUE TO GUST
STRONGER IN THE 35 KT RANGE OUT THE GATE. THOSE WINDS SHOULD
SLOWLY ABATE OVERNIGHT AS HIGH PRESSURE SWINGS IN FROM THE PLAINS
AND FLIPS FLOW NW...W...AND EVENTUALLY AROUND TO THE SW. CIGS WILL
CONTINUE TO CLEAR FROM W TO E TONIGHT...WITH THE WESTERN FLANK OF
CLOUDS THAT ARE OVERHEAD AND SHIFT EAST...STRETCHING FROM JUST
EAST OF JVL TO ARR AND SOUTH TO IKK. GENERALLY CLEAR SKIES AND
LIGHT WINDS ANTICIPATED FOR THE PRESENT TAFOR.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY...VFR...CHC -SN...MVFR LATE
* FRIDAY...VFR
* SATURDAY...SLT CHC RA...RASN...MVFR POSSIBLE
* SUNDAY...CHC SN...MVFR POSSIBLE
* MONDAY...VFR
SHEA
&&
.MARINE...
153 PM...LOW PRESSURE NEAR LAKE ERIE WILL CONTINUE TO LIFT
NORTHEAST TONIGHT AND INTO QUEBEC WEDNESDAY MORNING WHILE A LARGE
RIDGE OF HIGH PRESSURE EXTENDS FROM JAMES BAY SOUTHWEST INTO THE
CENTRAL PLAINS. THE GRADIENT BETWEEN THESE TWO FEATURES WILL
REMAIN STRONG BUT SLOWLY WEAKEN TONIGHT. SPEEDS/GUSTS PEAKED MID
MORNING AND EXPECT GALES IN THE 40-45 KT RANGE FOR MUCH OF THE
EVENING...BUT THREAT FOR STORM FORCE GUSTS TO 50 KT APPEARS TO
HAVE ENDED.
THE RIDGE NOTED ABOVE WILL SPLIT TONIGHT AS ONE AREA MOVES EAST
ACROSS NORTHERN QUEBEC AND THE SOUTHERN AREA DROPS SOUTH ACROSS THE
SOUTHERN PLAINS AND OHIO VALLEY WEDNESDAY. THE NORTHERN PORTION OF
THIS RIDGE WILL MOVE ACROSS LAKE MICHIGAN WEDNESDAY AFTERNOON WITH
WIND SPEEDS RAPIDLY DIMINISHING WEDNESDAY MORNING AND BECOMING
SOUTHWEST BY EVENING.
A WEAK LOW WILL DEVELOP OVER THE PLAINS WEDNESDAY NIGHT AND QUICKLY
MOVE ACROSS THE NORTHERN LAKES REGION THURSDAY AFTERNOON...
DRAGGING A COLD FRONT ACROSS THE LAKE THURSDAY NIGHT. THE GRADIENT
TIGHTENS BEHIND THIS FRONT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE PLAINS. BUT IN ADDITION TO THE TIGHTENING GRADIENT...COLDER
AIR WILL ALSO BE SPREADING ACROSS THE REGION AND EXPECT NORTHERLY
WINDS GUSTING TO AT LEAST 30 KTS WITH THE POTENTIAL FOR SOME GUSTS
TO 35 KTS. THIS HIGH THEN QUICKLY MOVES EAST ON FRIDAY WITH
SOUTHERLY WINDS DEVELOPING OVER THE LAKE FRIDAY NIGHT AS LOW
PRESSURE LIFTS NORTH ACROSS CANADA. ANOTHER COLD FRONT THEN MOVES
ACROSS THE LAKES REGION SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...LAKESHORE FLOOD ADVISORY...ILZ006-ILZ014 UNTIL 10 AM WEDNESDAY.
IN...LAKESHORE FLOOD ADVISORY...INZ001-INZ002 UNTIL 3 PM WEDNESDAY.
WIND ADVISORY...INZ001-INZ002 UNTIL 1 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
422 AM EST WED NOV 30 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL REPLACE THE ACTIVE WEATHER PATTERN OF THE LAST
FEW DAYS...RESULTING IN DRY CONDITIONS FOR THE REST OF THE WEEK.
HOWEVER...THE DRY WEATHER WILL BE SHORT-LIVED AS A COLD FRONT
ENTERS THE FORECAST AREA THIS WEEKEND BRINGING ANOTHER ROUND OF
PRECIP. AT THIS TIME...MODELS ARE SHOWING MORE OF A RAIN AND
RAIN/SNOW MIX. BEYOND THAT...SOME OF THE COLDEST AIR OF THE SEASON
WILL ENTER CENTRAL INDIANA WITH HIGHS ONLY TOPPING OFF IN THE 30S...
AND LOWS IN THE TEENS AND 20S.
&&
.NEAR TERM /EARLY MORNING AND TODAY/...
YESTERDAY/S LOW PRESSURE SYSTEM HAS MOVED OUT OF CENTRAL INDIANA
WITH THE SURFACE LOW CURRENTLY CENTERED OVER LAKE ONTARIO.
SO...THE ONLY CHALLENGE FOR TODAY WILL BE TIMING IN REGARD TO
CLEARING.
FAR WESTERN PORTIONS OF CENTRAL INDIANA ARE ALREADY STARTING TO
SEE SOME CLEARING. CLOUDS WILL CONTINUE TO BREAK UP FROM WEST TO
EAST THROUGH THE COURSE OF THE MORNING AS HIGH PRESSURE BUILDS
INTO THE FORECAST AREA. ENTIRE AREA SHOULD BE UNDER SUNNY SKIES BY
EARLY AFTERNOON IF NOT SOONER. HOWEVER...DO NOT EXPECT
TEMPERATURES TO RECOVER VERY QUICKLY THIS AFTERNOON. HIGHS WILL
ONLY TOP OFF IN THE UPPER 30S/LOW 40S WITH WEST/NORTHWEST FLOW.
MODELS ARE IN AGREEMENT...SO STUCK CLOSE TO GUIDANCE AND WENT WITH
ALLBLEND.
LATEST OBS ACROSS CENTRAL INDIANA ARE SHOWING TEMPS GENERALLY IN
THE LOW 30S WITH DEWPOINTS IN THE MID TO UPPER 20S. WINDS ARE OUT
OF THE NORTHWEST AT 5 TO 15 MPH.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
A BENIGN WEATHER PATTERN WILL REMAIN IN PLACE THROUGH ENTIRE SHORT
TERM PERIOD AS HIGH PRESSURE DOMINATES THE REGION. SO...THE ONLY
FOCUS WILL BE TEMPS.
FLOW ALOFT BECOMES A TAD MORE ZONAL TONIGHT...BUT SKIES WILL
REMAIN CLEAR. TOMORROW...A WEAK COLD FRONT WILL MOVE THROUGH
CENTRAL INDIANA...BUT IT WILL HAVE LITTLE AFFECT ON TEMPS AND
WILL BE LACKING MOISTURE. SO...WILL CONTINUE TO KEEP FORECAST DRY.
FRIDAY...A BROAD UPPER LEVEL TROUGH WILL MOVE ACROSS THE GREAT
LAKES REGION...CAUSING CLOUDS TO INCREASE ACROSS CENTRAL INDIANA.
LIGHT RAIN/SNOW SHOWERS COULD ALSO JUST SKIM THE NORTHEAST
PORTIONS OF FORECAST AREA ON FRIDAY MORNING WITH THIS DISTURBANCE.
SO INSERTED MENTION OF SLIGHT CHANCE POPS OVER THAT AREA...BUT
CONFIDENCE IS LOW.
TEMPS...STUCK CLOSE TO GUIDANCE FOR TODAY/S HIGHS...WHICH WILL PUT
FORECAST AREA IN THE UPPER 30S/LOW 40S. OVERNIGHT LOWS THE NEXT
FEW NIGHTS WILL BE CHILLY WITH CLEAR SKIES. AS A RESULT...TRENDED
ON COOLER SIDE OF GUIDANCE. LOWS WILL DIP INTO THE 20S TONIGHT AND
TOMORROW NIGHT. THURSDAY...WENT WITH MODEL BLEND...BUT CONFIDENCE
IS LOW DUE TO COLD FRONT PASSAGE. THESE NUMBERS MAY HAVE TO BE
LOWERED WITH FUTURE FORECAST ISSUANCES. FRIDAY...LEANED TOWARD THE
COOLER GFS IN REGARD TO HIGH/S. THE NAM DOES NOT SEEM TO BE
PICKING UP ON INCREASED CLOUD COVER FROM SYSTEM MOVING THROUGH THE
GREAT LAKES. FRIDAY NIGHT...CLOUDS WILL LINGER OVER CENTRAL
INDIANA AS THE NEXT SYSTEM MOVES CLOSER TO THE AREA.
SO...OVERNIGHT LOWS WILL BE A BIT WARMER WITH LOW 30S ACROSS THE
SOUTHERN HALF OF CENTRAL INDIANA AND MID 20S OVER THE NORTHERN HALF.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
BACK SIDE OF BROAD HIGH PRESSURE SHOULD KEEP MOST LOCATIONS DRY TO
START ON SATURDAY...BUT THE PRESENCE OF A WARM FRONT AND SOME WEAK
ISENTROPIC LIFT OVER THE WABASH VALLEY MAY BE ENOUGH TO GENERATE
LIGHT PRECIP IN WESTERN COUNTIES.
MORE SUBSTANTIAL PRECIP SET TO ARRIVE LATE SATURDAY NIGHT INTO
SUNDAY MORNING AS A WAVE OF LOW PRESSURE MOVES FROM THE CENTRAL
PLAINS INTO THE GREAT LAKES AND BRINGS A TRAILING COLD FRONT THROUGH
THE OHIO VALLEY. WHILE MODEL GUIDANCE IN GOOD AGREEMENT ON PRECIP
IMPACTING THE REGION FOR THE SECOND HALF OF THE WEEKEND WITH THE
FRONTAL PASSAGE...SOME DIFFERENCES ARE STILL PRESENT WITH REGARDS TO
THE AMOUNT OF ENERGY ALOFT THAT EJECTS FROM THE DEEP UPPER LOW
REMAINING BACK ACROSS BAJA CALIFORNIA IMPACTING SPEED OF THE
BOUNDARY AND AMOUNT OF MOISTURE PULLED NORTH INTO THE OHIO VALLEY.
FOR NOW WILL TAKE A BLENDED APPROACH WITH RESPECT TO TIMING AND
SPEED OF FRONTAL PASSAGE AND RUN WITH HIGH CHANCE TO LIKELY POPS FOR
SATURDAY NIGHT AND SUNDAY. LOW LEVEL THERMALS ALL SUPPORTIVE OF
PRECIP FALLING AS RAIN THROUGH SUNDAY...WITH POTENTIAL FOR SOME
MIXING WITH LIGHT SNOW SHOWERS SUNDAY NIGHT AND EARLY MONDAY AS THE
FRONT DROPS SOUTH OF THE OHIO RIVER. HIGHS WILL WARM INTO THE 40S
OVER THE WEEKEND.
COLDER AIR ADVECTING INTO THE REGION TO BEGIN THE NEW WEEK WITH A
REINFORCING SHOT OF ARCTIC AIR SET TO ARRIVE BY TUESDAY AS A SHARP
UPPER LOW DROPS INTO THE GREAT LAKES COURTESY OF THE POLAR JET
STREAM. HAVE KEPT DRY CONDITIONS THROUGHOUT FOR CENTRAL INDIANA WITH
LIMITED MOISTURE...BUT PRESENCE OF THE UPPER LOW WOULD APPEAR TO BE
A NICE SETUP FOR SOME LAKE EFFECT SNOWS ON TUESDAY AND THE ECMWF
HINTS AT POSSIBLE LAKE BANDS DROPPING SOUTHEAST FROM LAKE MICHIGAN
AND CLIPPING FAR NORTHEAST COUNTIES THROUGHOUT THE DAY TUESDAY. DOES
APPEAR COLDEST AIR OF THE SEASON ARRIVES FOR TUESDAY AS BOTH OP GFS
AND ECMWF SUGGEST 850MB TEMPS AT -14 TO -12C. HIGHS TUESDAY MAY
STRUGGLE TO GET INTO THE LOWER 30S ACROSS MUCH OF THE AREA. HIGH
PRESSURE RETURNS FOR MIDWEEK WITH A SLOW WARMING TREND.
&&
.AVIATION /DISCUSSION FOR THE 300900Z TAF UPDATE/...
MAIN CHANGE FOR THE UPDATE WAS TO DELAY CLEARING OF THE STRATOCU AT
THE TERMINALS AS RECENT SATELLITE DATA SHOWING REDEVELOPMENT TO THE
LOWER CLOUDS ACROSS WESTERN INDIANA. RUC INDICATING N/NW FLOW AT
925MB WHICH WILL STUNT EASTWARD PROGRESSION TO BACK EDGE OF THE
CLOUDS THROUGH DAYBREAK. STILL EXPECTING CLOUDS TO THIN AT THE
TERMINALS AROUND OR SHORTLY AFTER DAYBREAK.
06Z DISCUSSION FOLLOWS.
LINGERING PRECIPITATION EXPECTED TO END OVER THE TAF SITES BY
ISSUANCE TIME. CEILINGS CONTINUE TO RAPIDLY IMPROVE AS DRIER AIR
ADVECTS INTO THE AREA. LINGERING MVFR CEILINGS IN THE VICINITY OF
KIND/KBMG EXPECTED TO LIFT INTO A 030-040 DECK BY ISSUANCE
TIME....WITH THIS DECK SCATTERING OUT BY 300800Z OR SO. ONCE THIS
CLOUD DECK SCATTERS OUT...LITTLE IN THE WAY OF SIGNIFICANT CLOUD
COVER EXPECTED THROUGH 301800Z.
PRESSURE RISE MAX CURRENTLY WORKING IT/S WAY THROUGH THE LOCAL
AREA...SO SURFACE WIND GUSTS 20-25KTS SHOULD DIMINISH AFTER ABOUT
300800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
114 AM EST WED NOV 30 2011
.AVIATION...
06Z TAFS...WINTER STORM WILL CONTINUE TO WIND DOWN ACROSS THE AREA OVER
THE NEXT SEVERAL HOURS. A FAIRLY PROGRESSIVE UPPER LOW WILL SHIFT
NORTHEASTWARD INTO THE EASTERN GREAT LAKES REGION OVERNIGHT...WITH
DEFORMATION FORCING WANING THROUGH THE OVERNIGHT HOURS. IFR VSBYS
WITH SNOW SHOWERS ARE POSSIBLE AT KFWA OVER NEXT FEW HOURS...WITH
THE THREAT DIMINISHING BY AROUND 08Z AS DEFORMATION BAND CONTINUES
TO WEAKEN AND SHIFT EASTWARD. NORTHWEST WINDS SHOULD REMAIN
SOMEWHAT GUSTY OVERNIGHT...ESPECIALLY AT KFWA...BUT WIND GUSTS AT
BOTH TERMINALS SHOULD SUBSIDE AFTER 09Z. WHILE WEST TO EAST
CLEARING TREND HAS BEEN PROGRESSIVE ACROSS NORTHERN
ILLINOIS...HAVE NOTED SOME MVFR CIGS ON BACK EDGE OF CLOUD DECK
ACROSS EXTREME NERN IL/FAR NWRN INDIANA AND DID INDICATE TEMPO
HIGHER END MVFR CIGS AT KSBN THROUGH 09Z. REMAINDER OF THE
FORECAST SHOULD BE UNEVENTUL WITH SFC RIDGE AXIS SLOWLY BUILDING
INTO THE AREA ALLOWING FOR WINDS TO BACK TO THE WEST AROUND 10
KNOTS ON WEDNESDAY AFTERNOON. VFR CONDITIONS EXPECTED POST 12Z
THIS MORNING.
&&
.PREV DISCUSSION... /ISSUED 720 PM EST TUE NOV 29 2011/
UPDATE...
SUBSTANTIAL CHNGS WRT KSBN AS PROLIFIC MESOBANDED/CONVECTIVE
SNOWFALL TO MOST LKLY RMN EAST OF AIRFLD PER HRRR ANALYSIS. IN
ADDITION...RECENT STRONG SFC PRES RISES ACRS NRN IN SUGGESTS SFC
LOW AND ASSOCD BANDING TO JUMP EWD NEXT FEW HRS. FURTHER
SUBSTANTIATING HRRR IS WV IMAGERY SHOWING TIGHTLY CYCLCLY WOUND
DRY SLOT NOW INTO KFWA WITH ERLIER LULL/IMPROVEMENT TO
7SM...OCCLSN FCST TO SHIFT EWD OF MIDLVL CIRC CENTER NEAR KAOH
ATTM INTO ERN OH BY 06 UTC. FILLING PRECIP ANTICIPATED TO RETURN
EWD INTO KFWA AFT 01 UTC WITH POTNL FOR INTENSE BAND FM KHAI-KASW-
5W KOKK TO SHIFT EWD TO KFWA 02-05 UTC WITH PSBL LIFR MET CONDS.
AS ENTIRE SYSTEM LIFTS OUT TOWARD DAYBREAK...SHARP LWRG OF
SUBSIDENCE INVERSION PER KOXI PROXIMITY LAPS SNDG...TO BRING
ABRUPT END OF SNOW W-E ACRS NRN IN...NLT 03 UTC KSBN TO KFWA
AROUND 05 UTC. STRONG PRES RISES SHOULD BRING PD OF HIR GUSTS INTO
MID/UPR 20S KT RANGE...THOUGH IN ABSENCE OF STRONG CAA AND LWRG
SUBSIDENCE INVERSION THIS UPTICK SHOULD REMAIN SHORT-
LIVED...RELAXING AFTR MIDNIGHT.
ANTICIPATE UPDATE WITHIN NEXT HOUR TO TRIM WRN PERIPHERY ADVISORY
COUNTIES/LKLY DOWNGRADE SOUTH OF KOS/WHITLEY/ALLEN IN COUNTIES TO
ADVISORY. ALL ANTICIPATED CHANGES WL LARGELY BE IN LOCK STEP OF HRRR
3KM HRLY/15 MIN MESODATA...ASSUMPTIVE OF WELL CORRELATED RADAR/METAR
OBS TRENDS.
SHORT TERM.../TONIGHT/
..FIRST WIDESPREAD SNOW OF THE SEASON COMMENCING...
UPDATES ISSUED EARLIER GENERALLY ON TRACK WITH RAPID COOLING OF
COLUMN OCCURRING BETWEEN 18 AND 20Z. MANY LOCATIONS NOW REPORTING
SNOW OR A MIX OF SNOW/SLEET/RAIN. SNOW AMOUNTS INITIALLY MAY BE ON
LIGHTER SIDE WITH MELTING OCCURRING ON SLIGHTLY WARMER SURFACES.
HOWEVER AS UPPER LOW APPROACHES LATE THIS AFTERNOON AND EVENING AND
MESOBANDING BETTER ESTABLISHES SNOWFALL RATES SHOULD INCREASE ACROSS
MUCH OF THE WARNING AREA. SPORADIC LIGHTNING STRIKES SEEN SW OF THE
AREA IN MAIN MESOBAND WHICH WILL TRANSLATE THROUGH THE AREA INTO
TONIGHT.
HEAVIEST SNOWFALL WILL OCCUR BETWEEN 22Z TUES AND 6Z WEDS AS MAIN
DEFORMATION ZONE SHIFTS ACROSS THE FORECAST AREA. SEVERAL RUNS OF
THE HRRR HAVE SHOWN THE MAIN SWATH OF HEAVIER SNOW TO TAKE SHAPE
EITHER SIDE OF A MARION TO ANGOLA TO HILLSDALE LINE. THIS MODEL
DEPICTS UPWARDS OF 8 TO 12 INCHES OF SNOWFALL. THINK THIS IS LIKELY
OVER DONE WITH GREATER CONFIDENCE IN DECENT AREA OF 4 TO 7 INCHES OF
SNOW WITH AMOUNTS APPROACHING 8 ESPECIALLY ACROSS PORTIONS OF
NORTHEASTERN INDIANA INTO FAR SOUTHERN LWR MI AND FAR NW OHIO. WILL
LET EVE SHIFT MONITOR TRENDS OF AMOUNTS AND HEAVIEST BAND AND ADJUST
HEADLINES ACCORDINGLY. TEMPS WILL CONTINUE TO FALL AND BOTTOM OUT IN
THE UPPER 20S TO AROUND 30.
WINDS WILL ALSO INCREASE TONIGHT AS THE TIGHTLY WRAPPED LOW
CONTINUES TO MOVE AWAY. AS WE GET INTO THE OVERNIGHT HOURS THIS
COULD CAUSE SOME DRIFTING AND LOW BLOWING OF THE SNOW...BUT GIVEN
THE INITIAL WET CONTENT...NOT EXPECTED TO BE A SIG IMPACT.
LONG TERM...
MINOR ADJUSTMENTS TO THE TEMPERATURES WEDNESDAY AND WEDNESDAY NIGHT
TO TAKE INTO ACCOUNT OUR LATEST SNOWFALL FORECASTS AND EXPECTED
CLOUD COVER. HAVE NUDGED TEMPS DOWN FOR THE MAX T AND UP FROM
PREVIOUS GRIDS FOR OVERNIGHT LOW. WITH CYCLONIC FLOW OVER THE REGION
EXPECT THAT CLOUDS WILL PERSIST AND HAVE INCREASED CLOUD COVER - BUT
MAY NOT HAVE INCREASED ENOUGH FOR THURSDAY.
LONGWAVE PATTERN IS BEGINNING TO BE MUCH MORE AMPLIFIED AND THIS
SETS UP A PROGRESSIVE PATTERN OVER THE GREAT LAKES REGION BEGINNING
THURSDAY WITH ANOTHER VIGOROUS SHORTWAVE TO TO DIVE OUT OF THE
NORTHERN PLAINS BY SATURDAY...LEADING TO ANOTHER SHOT OF COLDER AIR
POISED TO DROP OUT OF THE CANADIAN PLAINS THIS COMING WEEKEND.
WITH A BRIEF WARMING TREND THU/FRI TEMPS WILL BE BELOW NORMAL
BEGINNING SAT-NEXT TUES.
WITH THE INCOMING SHORTWAVE ON SATURDAY...HAVE INCREASED POP TO MORE
CLOSELY MATCH SURROUNDING OFFICES AND WOULD EXPECT TO SEE ANOTHER
ACCUMULATING SNOWFALL DURING THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
INZ027-033-034.
WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
INZ006>009-017-018-025-026.
MI...WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
MIZ080-081.
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR OHZ005-
016-024-025.
WINTER WEATHER ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
OHZ015.
WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
OHZ001-002-004.
LM...GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LMZ043-046.
&&
$$
SHORT TERM...FISHER
LONG TERM...LEWIS
UPDATE...MURPHY
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS TOPEKA KS
335 PM CST WED NOV 30 2011
.DISCUSSION...
SHORT RANGE FORECAST (TONIGHT AND THURSDAY)...
20Z WATER VAPOR IMAGERY AND ASSOCIATED 500 MB RUC ANALYSIS SHOWS A
MID/UPPER LEVEL TROUGH OVER THE APPALACHIAN MOUNTAINS...WITH ANOTHER
H5 LOW DIVING SOUTHWARD THROUGH THE NORTHERN ROCKIES. BETWEEN THE
TWO TROUGHS IS A FLATTENED UPPER RIDGE OVER THE CENTRAL PLAINS WHICH
HAS BROUGHT FAIR CONDITIONS TO THE AREA. SOUTHERLY FLOW ALONG THE
EASTERN EDGE OF A DEEPENING SURFACE TROUGH ADVECTED WARM AIR INTO
NORTHEAST KANSAS...ALLOWING TEMPS TO REACH THE MID 50S ACROSS MUCH
OF THE AREA. EXPECT THE SURFACE TROUGH TO PUSH SOUTHEASTWARD AHEAD
OF AN ADVANCING SURFACE RIDGE...WHICH WILL BRING A COLD FRONT
THROUGH THE AREA BY MID DAY ON THURSDAY. EXPECT COOLER/DRYER AIR TO
MOVE IN BEHIND THE COLD FRONT FOR THURSDAY...ESPECIALLY FOR AREAS
ACROSS NORTH CENTRAL KANSAS WHICH WILL SEE THE FRONTAL PASSAGE
BEFORE PEAK HEATING. AREAS OF EASTERN KANSAS MAY SEE ANOTHER MILD
DAY AS SOUTHERLY FLOW SHOULD PERSIST THROUGH MUCH OF THE EARLY
AFTERNOON BEFORE THE FRONTAL PASSAGE IN THE EARLY EVENING. EXPECT
STRATUS TO BUILD IN BEHIND THE FRONT WHICH COULD POSSIBLY BRING SOME
SCATTERED SPRINKLES OR POSSIBLY SOME SNOW FLURRIES TO AREAS OF NORTH
CENTRAL KANSAS ON THURSDAY.
LEIGHTON
LONG TERM...THU NIGHT THROUGH NEXT WEDS.
FCST FOCUS REMAINS ON THE EVOLUTION OF STORM SYSTEM FRI INTO SAT.
RECENT MODEL GUIDANCE AND TRENDS CONTINUE TO SUGGEST A SLOWER
TRACK THAN THAT INDICATED BY THE NAM. GFS/ECMWF ARE THE FAVORED
MODELS FOR THIS FCST.
INITIAL MODIFIED POLAR AIRMASS WILL SETTLE INTO THE AREA THU
NIGHT WITH LIGHT WINDS AND SEASONABLY COLD TEMPS. BY FRI
AM...SOUTHERLY SFC WINDS WILL DEVELOP AS THE WESTERN U.S. LONGWAVE
TROUGH BEGINS TO BECOME PROGRESSIVE. LIFT WILL INCREASE THROUGH
THE DAY WITH SATURATION AND PRECIP DEVELOPMENT EXPECTED BY FRI
NIGHT. THERMAL PROFILES SUGGEST MAINLY RAIN EXCEPT FOR THE
NORTHWEST THIRD OF THE CWA WHERE DEPENDING ON THE WET BULB TEMPS
THERE MAY BE A RISK FOR FREEZING RAIN. GFS RAW MODEL NEAR SFC
TEMPS ARE WARMER THAN THE NUMERICAL MODEL GUIDANCE WHICH SUGGESTS
LOWS IN THE UPPER 20S TO LOWER 30S ACROSS THE NW THIRD SO
CONFIDENCE IN ICE THREAT REMAINS LOW AT THIS TIME. RIGHT NOW AREAS
ROUGHLY FROM ABILENE TO SENECA AND NW COULD SEE FREEZING PRECIP
FRI NIGHT. GFS CONTINUES TO WARM BOUNDARY LAYER TEMPS UP EARLY SAT
SUCH THAT ANY FZRA/ICE RISK SHOULD DECREASE HOWEVER WIDESPREAD
RAIN...SOME HEAVY SHOULD PERSIST ACROSS THE AREA AS THE UPPER
TROUGH MOVES THROUGH THE AREA AND THE SFC LOW TRACKS ACROSS
EASTERN KS. PRECIP SHOULD MIX WITH OR CHANGE TO SLEET OR SNOW FROM
WEST TO EAST BY LATER SAT/SAT NIGHT AS COLDER AIR ARRIVES ON THE
BACK SIDE OF THE SYSTEM. HOWEVER GFS ALSO SHOWS A DRY SLOT LATER
SAT AFTERNOON WHICH COULD BRING A BREAK IN THE PRECIP AND WOULD
ALSO LIMIT THE SNOW THREAT ACROSS NORTH-CENTRAL KS.
ALL IN ALL...LOOK FOR ANOTHER ROUND OF WIDESPREAD HEAVY RAINS OF 1
TO 2.5 INCHES FRI NIGHT INTO SAT WITH WHAT APPEARS TO BE A LOW RISK
FOR FREEZING PRECIP FRI NIGHT ACROSS PARTS OF THE AREA.
THE PATTERN LOOKS QUITE ACTIVE FOR THE REGION INTO NEXT WEEK WITH
ADDITIONAL POLAR COLD FRONTS EXPECTED TO DRIVE SOUTHWARD THROUGH
THE PLAINS. THE ACTUAL LONGWAVE TROUGH AXIS MAY NOT PASS THROUGH
THE REGION UNTIL MID WEEK SO CLOUDS/SOME LOW PRECIP CHCS MAY
LINGER ACROSS SOUTHERN KS BUT IT LOOKS DRY BUT COLD ACROSS NE KS.
CO
&&
.AVIATION...
VFR CONDITIONS PERSIST THROUGH THE NEXT 24 HOUR PERIOD. STEEP
SFC PRESSURE GRADIENT OVER KMHK AND THE HIGHER ELEVATION OVER
KFOE WILL INCREASE SOUTHERLY WIND GUSTS OVER 20 KTS WEDNESDAY
AFTERNOON.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1134 PM CST TUE NOV 29 2011
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT RANGE FORECAST (TONIGHT AND WEDNESDAY)...
20Z WATER VAPOR IMAGERY AND ASSOCIATED 500 MB RUC ANALYSIS SHOWS A
DEEP CUT OFF LOW PRESSURE SYSTEM SLOWLY MOVING NORTHEASTWARD THROUGH
THE OHIO RIVER VALLEY...BRINGING NORTHWESTERLY MID LEVEL FLOW OVER
THE CENTRAL U.S. A SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST
FLOW IS CURRENTLY PUSHING THROUGH THE AREA...HOWEVER MEAGER LIFT
FROM THIS QUICKLY MOVING SHORTWAVE WILL ONLY BRING SOME SCATTERED
HIGH CLOUDS FOR THIS AFTERNOON. AT THE SURFACE A SURFACE RIDGE OF
HIGH PRESSURE CURRENTLY SITS OVER CENTRAL KANSAS CREATING TIGHT
GRADIENT WITH SUBSEQUENT GUSTY NORTH-NORTHWEST WINDS ACROSS FAR
EASTERN KANSAS. A NARROW BAND OF DRY AIR HAS MOVED INTO NORTH
CENTRAL KANSAS AS DEWPOINTS HAVE MIXED INTO THE SINGLE
DIGITS...HOWEVER DUE TO THE LIGHT WINDS NEAR THE CENTER OF THE
SURFACE HIGH...FIRE DANGER IS NOT VERY HIGH IN THIS AREA DESPITE THE
VERY DRY AIR.
OVERNIGHT THE SURFACE RIDGE MOVES OVER NORTHEAST KANSAS CAUSING
WINDS TO GO CALM. WITH SKIES CLEARING OUT RADIATIONAL COOLING WILL
ALLOW TEMPERATURES TO DROP INTO THE LOWER TO MID 20S. WOULD HAVE
GONE A LITTLE COOLER IN NORTH CENTRAL KANSAS BUT SOUTHERLY FLOW
ALONG THE WESTERN EDGE OF THE EASTWARD MOVING SURFACE RIDGE WILL
ALLOW FOR SOME WEAK WARM AIR ADVECTION AS WELL AS SOME BOUNDARY
LAYER MIXING. THESE FACTORS WILL HELP TO KEEP TEMPERATURES A LITTLE
WARMER THAN AREAS FURTHER EAST. LOW LYING AREAS AND RIVER VALLEYS
EAST OF HIGHWAY 75 COULD SEE TEMPS DROP INTO THE UPPER TEENS AS
SOUTHERLY FLOW WILL LIKELY NOT BEGIN IN THESE AREAS UNTIL EARLY WED
MORNING.
WEDNESDAY WILL BRING ANOTHER MOSTLY CLEAR DAY WITH SLIGHTLY WARMER
TEMPERATURES THAN TUESDAY. SOUTHERLY FLOW WILL ALLOW FOR WARM AIR
ADVECTION EAST OF A DEEPENING SURFACE TROUGH WHICH WILL COME OFF THE
WESTERN HIGH PLAINS AND MOVE EAST INTO THE CENTRAL PLAINS. UTILIZED
A MIX DOWN METHOD FROM THE 900 MB LEVEL FOR WEDNESDAYS HIGHS.
TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN THE DEEPENING LOW AND
THE DEPARTING SURFACE HIGH WILL CAUSE THE SOUTHERLY WINDS TO PICK UP
IN INTENSITY THROUGHOUT THE DAY ON WEDNESDAY.
JL
EXTENDED RANGE FORECAST (WEDNESDAY NIGHT THROUGH TUESDAY)...
AN UPPER LEVEL TROUGH WILL DIG SOUTHWARD ACROSS THE WESTERN CONUS
INTO THE DESERT SOUTHWEST BY THURSDAY EVENING. A MINOR H5 WILL MOVE
EAST ACROSS THE NORTHERN AND CENTRAL PLAINS WEDNESDAY NIGHT.
LOW-LEVEL CAA ACROSS THE NORTHERN PLAINS WILL CAUSE A SURFACE COLD
FRONT TO PUSH SOUTHWARD ACROSS THE CWA THURSDAY MORNING. HIGHS MAY
OCCUR DURING THE MID AND LATE MORNING HOURS ON THURSDAY ACROSS
SOUTHEAST KS...WITH TEMPERATURES HOLDING STEADY OR SLOWLY FALLING
INTO THE LOWER 40S BY AFTERNOON. NORTH WINDS WILL INCREASE 20 TO 25
MPH WITH GUSTS OF 35 TO 45 MPH BEHIND THE COLD FRONT. THERE MAY BE
SOME SNOW FLURRIES EARLY THURSDAY MORNING ACROSS THE NORTHERN
COUNTIES OF THE CWA.
FRIDAY...WILL BE COOL WITH INCREASING HIGH CLOUDINESS. WINDS WILL
SHIFT TO THE SOUTHEAST BY LATE AFTERNOON AS A LEE SFC TROUGH DEEPENS
ACROSS THE HIGH PLAINS. HIGHS ON FRIDAY WILL ONLY REACH THE MID TO
UPPER 30S. THE NAM MODEL SOLUTION HAS BEEN VERY INCONSISTENT AND
ERRONEOUS THE PAST 48 HOURS. THE NAM IS WAY TOO PROGRESSIVE LIFTING
THE CLOSED UPPER LOW INTO THE SOUTHERN HIGH PLAINS LATE FRIDAY
AFTERNOON. IF FOR SOME REASON IT WERE TO VERIFY THEN PRECIP MAY
BEGIN DEVELOPING ACROSS THE SOUTHERN COUNTIES OF THE CWA LATE FRIDAY
AFTERNOON AND SPREAD NORTHWARD INTO THE EARLY EVENING HOURS. ALL
OTHER OPERATIONAL NUMERICAL MODELS SHOW THE CLOSED UPPER LOW
REMAINING ACROSS THE DESERT SOUTHWEST INTO FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...A PIECE OF THE UPPER LOW
ACROSS THE DESERT SOUTHWEST WILL LIFT NORTHEAST INTO THE CENTRAL
PLAINS ON SATURDAY. THE ECMWF MODEL SHOWS STRONG WAA DEVELOPING
FRIDAY NIGHT WHICH SHOULD CAUSE SFC TEMPS AND DEWPOINTS TO RISE
ABOVE FREEZING ACROSS MUCH OF THE CWA BY 6Z SAT. THE GFS AND GEM
HAVE BEEN CONVERGING TOWARDS THE ECMWF...BUT CONTINUE TO BE A BIT
COOLER. I WILL BE LEANING A BIT MORE TOWARDS THE ECMWF DURING THIS
FORECAST PERIOD. LOW TEMPERATURES WILL OCCUR DURING THE MID EVENING
HOURS OF FRIDAY...THEN SLOWLY RISE THROUGH THE NIGHT. ISENTROPIC
LIFT AND ASCENT AHEAD OF THE APPROACHING H5 TROUGH WILL CAUSE LIGHT
RAIN TO DEVELOP. IF THERE IS ENOUGH LOW-LEVEL DRY AIR IN PLACE AS
THE RAIN DEVELOPS THEN WET-BULB COOLING MAY ALLOW SURFACE
TEMPERATURES ACROSS THE NORTHERN AND WESTERN COUNTIES TO DROP BELOW
FREEZING. THERE MAY BE SOME LIGHT PERIODS OF FREEZING RAIN FRIDAY
EVENING BEFORE IT CHANCES TO LIGHT RAIN. ROAD SURFACE ARE FAIRLY
WARM...THUS THE ONLY SLICKS SPOTS THAT MAY DEVELOP FRIDAY EVENING
MAY BE ON BRIDGES AND OTHER ELEVATED ROAD SURFACES.
THE RAIN ON SATURDAY MAY BEGIN TO MIX WITH SNOW ACROSS NORTH CENTRAL
KS DURING THE AFTERNOON HOURS AS THE H5 TROUGH LIFTS NORTHEAST
ACROSS CENTRAL KS INTO EASTERN NE. THE NORTHERN COUNTIES MAY SEE A
PERIOD OF LIGHT SNOW SATURDAY NIGHT...THE RAIN WILL MIX WITH SNOW
ACROSS THE REMAINDER OF THE CWA THROUGH THE EVENING HOURS. THERE MAY
BE A BRIEF PERIOD OF LIGHT SNOW ACROSS NORTHEAST AND EAST CENTRAL KS
BEFORE THE PRECIP MOVES EAST OF THE CWA LATE SATURDAY NIGHT INTO
SUNDAY MORNING. ATTM...THE ACCUMULATING SNOW WILL MOST LIKELY
REMAIN WEST AND NORTH OF THE CWA...FROM WEST CENTRAL KS INTO EASTERN
NE WHERE SEVERAL INCHES OF SNOW MAY ACCUMULATE. THE NORTH CENTRAL
COUNTIES MAY SEE AROUND AN INCH OF SNOW ON GRASSY SURFACES SATURDAY
NIGHT. HIGHS ON SATURDAY WILL REACH THE LOWER TO MID 40S SOUTH OF
I-70 WITH MID TO UPPER 30S NORTH OF I-70. OVERNIGHT LOWS ON SATURDAY
WILL SLOWLY DROP INTO THE 20S.
SUNDAY THROUGH TUESDAY...THE MAIN H5 LOW WILL REMAIN CUTOFF ACROSS
THE SOUTHWEST CONUS AS A LONGER WAVE LENGTH H5 TROUGH DEVELOPS
ACROSS THE EASTERN CONUS. NORTHWEST FLOW ALOFT AND A COLD SFC HIGH
PRESSURE WILL KEEP HIGHS IN THE MID 30S AND OVERNIGHT LOWS IN THE
TEENS AND LOWER 20S.
GARGAN
&&
.AVIATION...
VFR TO CONTINUE THROUGH THE PERIOD. WINDS LIGHT AND VARIABLE EARLY
WITH SURFACE HIGH OVER TERMINALS THEN BECOMING SOUTH NEAR 8 KTS BY
14Z. WINDS INCREASING TO AROUND 12 KTS WITH GUSTS NEAR 21 KTS
AFTER 18Z. WINDS THEN DECOUPLE AND BACK TO SOUTH SOUTHEAST UNDER 10
KTS AFTER 01/00Z. DRY BOUNDARY LAYER WILL INHIBIT FOG FORMATION.
53
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1020 PM EST THU DEC 1 2011
.SYNOPSIS...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC REGION FROM THE WEST
TONIGHT THROUGH WEEKEND. A WEAK...DRY COLD FRONT WILL CROSS INTO
THE AREA FRIDAY NIGHT...BRINGING SLIGHTLY COOLER TEMPERATURES
SATURDAY. MILDER CONDITIONS RETURN FOR THE LATTER HALF OF THE
WEEKEND INTO EARLY NEXT WEEK AHEAD OF A SLOW MOVING COLD
FRONT...WHICH APPROACHES THE REGION FROM THE WEST BY THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
LATEST WX ANALYSIS DEPICTS ~1028MB SURFACE HIGH PRESSURE OVER
E KY/TN. ALOFT...TROUGH-RIDGE-TROUGH PATTERN EVIDENT ON RUC H5
ANALYSIS AS MID LEVEL TROUGHING HAS NOW TRANSITIONED OFF THE EAST
COAST...WITH LOW AMPLITUDE H5 RIDGING TO THE WEST OVER THE GULF
COAST/LOWER MS VALLEY...WITH CLOSED OFF/POSITIVELY TILTED UPPER
LEVEL LOW PRESSURE REMAINS IN PLACE OVER BAJA/SOUTHERN
CALIFORNIA.
BREEZY CONDITIONS STILL IN PLACE OVER MAINLY COASTAL ZONES THIS
AFTERNOON AS A RESULT OF PRESSURE GRADIENT BETWEEN DEPARTING MID
LEVEL TROUGH...AND HIGH PRESSURE TO THE WEST. COASTAL AREAS
SHOULD CONTINUE TO BE BREEZY (GUSTS TO 15-17 KT) FOR A FEW MORE
HOURS BEFORE DECOUPLING/RELAXING PRESSURE GRADIENT ALLOWS FOR
WINDS TO DROP OFF EARLY THIS EVENING. OTHERWISE...A MOSTLY CLEAR
AND PLEASANT LATE FALL AFTERNOON ACROSS THE CWA...MAXIMA WL AVERAGE
OUT INTO THE MID 50S INLAND...LOW TO MID 50S OVER COASTAL ZONES.
CLEAR SKIES/LIGHT WINDS PORTEND TO GOOD RADIATING CONDITIONS
TONIGHT. LOOKING FOR TEMPERATURES BE CLOSE TO/JUST BELOW LAST
NIGHTS/THIS MORNING`S LOWS. LOOK FOR LOWS INTO THE M-U 20S
INLAND...LOW TO MID 30S OVER COASTAL ZONES.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
LATE WEEK/WEEKEND TIME FRAME CHARACTERIZED BY SLOWLY BUILDING UPPER
LEVEL RIDGING WITH TIME OVER THE EASTERN CONUS...RESULTING IN
CONTINUED DRY WEATHER THROUGH THE PERIOD.
FRIDAY...
HIGH PRESSURE BECOMES ENTRENCHED OVER THE MID ATLANTIC
STATES THROUGH THE WEEKEND. AS A CUTOFF LOW DEVELOPS OVER THE
SOUTHWESTERN US...A WEAK UPPER LEVEL TROUGH WILL BECOME SEPARATED
FROM IT AND DRIFT ACROSS THE NORTHERN PLAINS/UPPER GREAT
LAKES...BEFORE SLOWLY PUSHING ACROSS NEW ENGLAND BY FRIDAY NIGHT.
THIS FEATURE WILL EVENTUALLY PUSH WEAK/DRY FRONTAL BOUNDARY TO OUR
NORTH THROUGH THE REGION LATE TOMORROW INTO SATURDAY WITH LITTLE
MORE THAN A FEW MID-HIGH CLOUDS PUSHING ACROSS THE AREA. MAXIMA
SLIGHTLY WARMER THAN TODAY`S VALUES...GENERALLY INTO THE M/U 50S
AREA WIDE...NEAR 60 WELL INLAND. SO WHILE WE CAN EXPECT A SLIGHTLY
MILDER EVENING FRIDAY NIGHT...HAVE SIDED CLOSER TO COOLER ENVELOPE
OF MAV GUIDANCE IN EXPECTATION OF LIGHT WINDS OVER LAND AND STILL
RELATIVELY SCANT MID LEVEL CLOUD COVER AS HIGH PRESSURE SLIDES
OVERHEAD. EARLY MORNING LOWS FRI NIGHT/SAT MORNING GENERALLY INTO
THE L-M30S TO NEAR 40 ALONG COASTAL ZONES.
SATURDAY...
THE SURFACE HIGH BECOMES POSITIVELY TILTED ON SATURDAY AS THE
RIDGE AXIS BEGINS TO SHIFT OFFSHORE. DESPITE AFOREMENTIONED
WARMING WITH TIME ALOFT AS SUBTROPICAL RIDGE BEGINS TO BUILD ACROSS
THE SOUTHEASTERN CONUS...TEMPERATURES WILL BE MODESTLY COOLER
SATURDAY DUE TO THE INFLUENCE OF MODIFYING ~1036MB SFC HIGH
PRESSURE PUSHING IN FROM THE WEST. AS WE`VE SEEN SEVERAL TIMES
ALREADY THIS FALL...LIMITED MIXING NOTED ON FORECAST SOUNDINGS FOR
SATURDAY (GENERALLY TO ~950-925MB) WILL KEEP TEMPERATURES A BIT
LOWER THAN LOCAL THICKNESS TOOLS AND WARMER MAV GUIDANCE DEPICT.
AS SUCH...HAVE GONE CLOSER TO COOLER MET VALUES FOR MAXIMA ON
SATURDAY WHICH YIELD SEASONABLE...ALBEIT SLIGHTLY COOLER...MAXIMA
INTO THE LOW TO MID 50S.
SATURDAY NIGHT/SUNDAY...
SURFACE HIGH PIVOTS TO THE MID-ATLANTIC/SE COAST AND THEN
OFFSHORE SAT NIGHT THROUGH SUNDAY...WITH DEVELOPING RETURN (SOUTH-
SOUTHEAST) FLOW AND CONTINUED BUILDING OF RIDGING ALOFT INITIATING
MODERATING TEMPERATURE TREND FOR SATURDAY NIGHT THROUGH THE EARLY
PORTION OF NEXT WEEK. LOOK FOR EARLY MORNING LOWS CONTINUED DRY
AND MILDER CONDITIONS SUNDAY WITH MAXIMA INTO THE L-M 60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
OVERALL PATTERN IN THE EXTENDED FAVORS A DOMINANT MID/UPPER LEVEL
RIDGE CENTERED FROM THE GULF OF MEXICO ENE ACRS FLORIDA AND TOWARDS
BERMUDA. MEANWHILE...A DEEP TROUGH OVER CENTRAL CANADA WILL
GRADUALLY PUSH SOUTH AND TAKE ON A POSITIVE TILT (OR EVEN BECOME
CUTOFF) OVER THE CENTRAL CONUS. THIS SETUP WILL BE VERY SLOW TO
CHANGE THROUGH THE MIDDLE OF NEXT WEEK...AND WILL KEEP BULK OF
PRECIPITATION OFF TO OUR WEST UNTIL WED. FOR THE MID ATLC AND SE
STATES...THIS WILL ALSO TRANSLATE INTO WELL ABOVE AVG TEMPERATURES
MON-TUE...AND POSSIBLY WED BEFORE COOLING DOWN TO AROUND AVG ON THU.
GIVEN THE CONTINUED MODEL DISCREPANCIES (LATEST ECMWF REMAINING
ABOUT 12-18 HRS SLOWER THAN THE GFS/GLOBAL GEM
ENSEMBLES....CONFIDENCE IN TUE-THU FCST IS LOWER THAN AVG.
AS WITH PREVIOUS FCST...HAVE GENLY BROAD-BRUSHED A LOW CHANCE POP
ACRS THE NW ZONES...TO DRY OR SLIGHT CHANCE ELSEWHERE FROM LATE MON
THROUGH TUE. WILL FOCUS HIGHEST POPS DURING THE DAY WED/WED EVENING
AS A BLEND OF MODEL TIMING PUSHES THE SFC COLD FRONT THROUGH.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
HIGH PRES CENTERED OVER THE OH VALLEY WILL KEEP SKIES CLEAR
THROUGH THE TAF PERIOD AND INTO LATE FRI. A MOSTLY DRY COLD FRONT
WILL APPROACH LATE FRI INTO SAT. VFR CONDITIONS ARE EXPECTED
THROUGH THE WEEKEND.
&&
.MARINE...
SCA HEADLINES ARE IN THE PROCESS OF BEING TRIMMED BACK W/ AFTN
PACKAGE...GENLY KEEPING SCA HEADLINES IN EFFECT OVER SOUTHERN AREAS
INTO THE EVENING...WHILE WINDS ARE A BIT LIGHTER TO THE NORTH WHERE
THE HEADLINES ARE ENDING. FOR SOUTHERN COASTAL WATERS THE SCA
HEADLINES MAY NEED TO BE EXTENDED BEYOND THE EVENING IF SEAS ARE
SLOWER TO DROP THAN FCST.
QUIET CONDITIONS FRI...FOLLOWED BY ANOTHER BOUNDARY/COOL SURGE FRI
NIGHT...WITH MARGINAL SCA EVENT LIKELY ONCE AGAIN OVER THE
BAY....AND POSSIBLE ON THE COASTAL WATERS. AS THIS IS LATER 3RD
PERIOD...HAVE DECIDED TO WAIT UNTIL CURRENT HEADLINES END BEFORE
RAISING ANOTHER SET (ALTHOUGH FCST DOES INCLUDE SCA CONDITIONS).
THIS SURGE IS FAIRLY BRIEF...AND SHOULD END BY LATE SAT MORNING
ASIDE FROM LINGERING 5 FT SEAS OVER SOUTHERN COASTAL WATERS.
OTHERWISE...BENIGN SAT EVENING THROUGH MON AS HIGH PRESSURE SETTLES
OVER THE REGION AHEAD OF THE NEXT COLD FRONT. WINDS GRADUALLY TURN
SOUTHERLY SUN-TUE BUT WIND SPEEDS LOOK TO AVG 10-15 KT OR LESS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MAM
NEAR TERM...BKH/MAM
SHORT TERM...MAM/BMD
LONG TERM...LKB
AVIATION...DAP/JEF
MARINE...MPR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
953 PM EST THU DEC 1 2011
.SYNOPSIS...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC REGION FROM THE WEST
TONIGHT THROUGH WEEKEND. A WEAK...DRY COLD FRONT WILL CROSS INTO
THE AREA FRIDAY NIGHT...BRINGING SLIGHTLY COOLER TEMPERATURES
SATURDAY. MILDER CONDITIONS RETURN FOR THE LATTER HALF OF THE
WEEKEND INTO EARLY NEXT WEEK AHEAD OF A SLOW MOVING COLD
FRONT...WHICH APPROACHES THE REGION FROM THE WEST BY THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
LATEST WX ANALYSIS DEPICTS ~1028MB SURFACE HIGH PRESSURE OVER
E KY/TN. ALOFT...TROUGH-RIDGE-TROUGH PATTERN EVIDENT ON RUC H5
ANALYSIS AS MID LEVEL TROUGHING HAS NOW TRANSITIONED OFF THE EAST
COAST...WITH LOW AMPLITUDE H5 RIDGING TO THE WEST OVER THE GULF
COAST/LOWER MS VALLEY...WITH CLOSED OFF/POSITIVELY TILTED UPPER
LEVEL LOW PRESSURE REMAINS IN PLACE OVER BAJA/SOUTHERN
CALIFORNIA.
BREEZY CONDITIONS STILL IN PLACE OVER MAINLY COASTAL ZONES THIS
AFTERNOON AS A RESULT OF PRESSURE GRADIENT BETWEEN DEPARTING MID
LEVEL TROUGH...AND HIGH PRESSURE TO THE WEST. COASTAL AREAS
SHOULD CONTINUE TO BE BREEZY (GUSTS TO 15-17 KT) FOR A FEW MORE
HOURS BEFORE DECOUPLING/RELAXING PRESSURE GRADIENT ALLOWS FOR
WINDS TO DROP OFF EARLY THIS EVENING. OTHERWISE...A MOSTLY CLEAR
AND PLEASANT LATE FALL AFTERNOON ACROSS THE CWA...MAXIMA WL AVERAGE
OUT INTO THE MID 50S INLAND...LOW TO MID 50S OVER COASTAL ZONES.
CLEAR SKIES/LIGHT WINDS PORTEND TO GOOD RADIATING CONDITIONS
TONIGHT. LOOKING FOR TEMPERATURES BE CLOSE TO/JUST BELOW LAST
NIGHTS/THIS MORNING`S LOWS. LOOK FOR LOWS INTO THE M-U 20S
INLAND...LOW TO MID 30S OVER COASTAL ZONES.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
LATE WEEK/WEEKEND TIME FRAME CHARACTERIZED BY SLOWLY BUILDING UPPER
LEVEL RIDGING WITH TIME OVER THE EASTERN CONUS...RESULTING IN
CONTINUED DRY WEATHER THROUGH THE PERIOD.
FRIDAY...
HIGH PRESSURE BECOMES ENTRENCHED OVER THE MID ATLANTIC
STATES THROUGH THE WEEKEND. AS A CUTOFF LOW DEVELOPS OVER THE
SOUTHWESTERN US...A WEAK UPPER LEVEL TROUGH WILL BECOME SEPARATED
FROM IT AND DRIFT ACROSS THE NORTHERN PLAINS/UPPER GREAT
LAKES...BEFORE SLOWLY PUSHING ACROSS NEW ENGLAND BY FRIDAY NIGHT.
THIS FEATURE WILL EVENTUALLY PUSH WEAK/DRY FRONTAL BOUNDARY TO OUR
NORTH THROUGH THE REGION LATE TOMORROW INTO SATURDAY WITH LITTLE
MORE THAN A FEW MID-HIGH CLOUDS PUSHING ACROSS THE AREA. MAXIMA
SLIGHTLY WARMER THAN TODAY`S VALUES...GENERALLY INTO THE M/U 50S
AREA WIDE...NEAR 60 WELL INLAND. SO WHILE WE CAN EXPECT A SLIGHTLY
MILDER EVENING FRIDAY NIGHT...HAVE SIDED CLOSER TO COOLER ENVELOPE
OF MAV GUIDANCE IN EXPECTATION OF LIGHT WINDS OVER LAND AND STILL
RELATIVELY SCANT MID LEVEL CLOUD COVER AS HIGH PRESSURE SLIDES
OVERHEAD. EARLY MORNING LOWS FRI NIGHT/SAT MORNING GENERALLY INTO
THE L-M30S TO NEAR 40 ALONG COASTAL ZONES.
SATURDAY...
THE SURFACE HIGH BECOMES POSITIVELY TILTED ON SATURDAY AS THE
RIDGE AXIS BEGINS TO SHIFT OFFSHORE. DESPITE AFOREMENTIONED
WARMING WITH TIME ALOFT AS SUBTROPICAL RIDGE BEGINS TO BUILD ACROSS
THE SOUTHEASTERN CONUS...TEMPERATURES WILL BE MODESTLY COOLER
SATURDAY DUE TO THE INFLUENCE OF MODIFYING ~1036MB SFC HIGH
PRESSURE PUSHING IN FROM THE WEST. AS WE`VE SEEN SEVERAL TIMES
ALREADY THIS FALL...LIMITED MIXING NOTED ON FORECAST SOUNDINGS FOR
SATURDAY (GENERALLY TO ~950-925MB) WILL KEEP TEMPERATURES A BIT
LOWER THAN LOCAL THICKNESS TOOLS AND WARMER MAV GUIDANCE DEPICT.
AS SUCH...HAVE GONE CLOSER TO COOLER MET VALUES FOR MAXIMA ON
SATURDAY WHICH YIELD SEASONABLE...ALBEIT SLIGHTLY COOLER...MAXIMA
INTO THE LOW TO MID 50S.
SATURDAY NIGHT/SUNDAY...
SURFACE HIGH PIVOTS TO THE MID-ATLANTIC/SE COAST AND THEN
OFFSHORE SAT NIGHT THROUGH SUNDAY...WITH DEVELOPING RETURN (SOUTH-
SOUTHEAST) FLOW AND CONTINUED BUILDING OF RIDGING ALOFT INITIATING
MODERATING TEMPERATURE TREND FOR SATURDAY NIGHT THROUGH THE EARLY
PORTION OF NEXT WEEK. LOOK FOR EARLY MORNING LOWS CONTINUED DRY
AND MILDER CONDITIONS SUNDAY WITH MAXIMA INTO THE L-M 60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
OVERALL PATTERN IN THE EXTENDED FAVORS A DOMINANT MID/UPPER LEVEL
RIDGE CENTERED FROM THE GULF OF MEXICO ENE ACRS FLORIDA AND TOWARDS
BERMUDA. MEANWHILE...A DEEP TROUGH OVER CENTRAL CANADA WILL
GRADUALLY PUSH SOUTH AND TAKE ON A POSITIVE TILT (OR EVEN BECOME
CUTOFF) OVER THE CENTRAL CONUS. THIS SETUP WILL BE VERY SLOW TO
CHANGE THROUGH THE MIDDLE OF NEXT WEEK...AND WILL KEEP BULK OF
PRECIPITATION OFF TO OUR WEST UNTIL WED. FOR THE MID ATLC AND SE
STATES...THIS WILL ALSO TRANSLATE INTO WELL ABOVE AVG TEMPERATURES
MON-TUE...AND POSSIBLY WED BEFORE COOLING DOWN TO AROUND AVG ON THU.
GIVEN THE CONTINUED MODEL DISCREPANCIES (LATEST ECMWF REMAINING
ABOUT 12-18 HRS SLOWER THAN THE GFS/GLOBAL GEM
ENSEMBLES....CONFIDENCE IN TUE-THU FCST IS LOWER THAN AVG.
AS WITH PREVIOUS FCST...HAVE GENLY BROAD-BRUSHED A LOW CHANCE POP
ACRS THE NW ZONES...TO DRY OR SLIGHT CHANCE ELSEWHERE FROM LATE MON
THROUGH TUE. WILL FOCUS HIGHEST POPS DURING THE DAY WED/WED EVENING
AS A BLEND OF MODEL TIMING PUSHES THE SFC COLD FRONT THROUGH.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
HIGH PRES CENTERED OVER THE OH VALLEY WILL KEEP SKIES CLEAR
THROUGH THE TAF PERIOD AND INTO LATE FRI. A MOSTLY DRY COLD FRONT
WILL APPROACH LATE FRI INTO SAT. VFR CONDITIONS ARE EXPECTED
THROUGH THE WEEKEND.
&&
.MARINE...
SCA HEADLINES ARE IN THE PROCESS OF BEING TRIMMED BACK W/ AFTN
PACKAGE...GENLY KEEPING SCA HEADLINES IN EFFECT OVER SOUTHERN AREAS
INTO THE EVENING...WHILE WINDS ARE A BIT LIGHTER TO THE NORTH WHERE
THE HEADLINES ARE ENDING. FOR SOUTHERN COASTAL WATERS THE SCA
HEADLINES MAY NEED TO BE EXTENDED BEYOND THE EVENING IF SEAS ARE
SLOWER TO DROP THAN FCST.
QUIET CONDITIONS FRI...FOLLOWED BY ANOTHER BOUNDARY/COOL SURGE FRI
NIGHT...WITH MARGINAL SCA EVENT LIKELY ONCE AGAIN OVER THE
BAY....AND POSSIBLE ON THE COASTAL WATERS. AS THIS IS LATER 3RD
PERIOD...HAVE DECIDED TO WAIT UNTIL CURRENT HEADLINES END BEFORE
RAISING ANOTHER SET (ALTHOUGH FCST DOES INCLUDE SCA CONDITIONS).
THIS SURGE IS FAIRLY BRIEF...AND SHOULD END BY LATE SAT MORNING
ASIDE FROM LINGERING 5 FT SEAS OVER SOUTHERN COASTAL WATERS.
OTHERWISE...BENIGN SAT EVENING THROUGH MON AS HIGH PRESSURE SETTLES
OVER THE REGION AHEAD OF THE NEXT COLD FRONT. WINDS GRADUALLY TURN
SOUTHERLY SUN-TUE BUT WIND SPEEDS LOOK TO AVG 10-15 KT OR LESS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...MAM/BMD
LONG TERM...LKB
AVIATION...DAP/JEF
MARINE...MPR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1052 AM EST WED NOV 30 2011
.SYNOPSIS...
RAIN AND SNOW SHOWERS WILL DIMINISH TODAY AS LOW PRESSURE MOVES OFF
TO THE NORTHEAST. BELOW NORMAL TEMPERATURES WILL PERSIST INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED WEATHER TYPE...TEMPS...AND SNOW AMOUNTS FOR THE RIDGE
LOCATIONS FOR THE MID MORNING UPDATE. WHILE CLOUD TOP TEMPERATURES
CONTINUE TO BE AN ISSUE ALLOWING FOR SOME OF THE PRECIPITATION TO
FALL AS DRIZZLE AND RAIN...THINK THAT AS THE DEFORMATION ZONE
PIVOTS SOUTHEASTWARD...SNOW WILL BE THE PRIMARY WEATHER TYPE. AS
THE WINDS SHIFT MORE NORTHWESTERLY THIS AFTERNOON...SNOW WILL
CONTINUE IN THE HIGHER ELEVATIONS. SINCE 3 INCHES OF SNOW WAS
REPORTED SINCE YESTERDAY IN THE WV RIDGES...FEEL IT REASONABLE
THAT ANOTHER 1-2 COULD FALL BEFORE THE SNOW ENDS TONIGHT. KEPT
TEMPERATURES NEARLY STEADY FOR THE AFTERNOON.
WINDS WILL BE A BIT GUSTY...RANGING FROM 20 MPH IN THE SOUTH TO 30
MPH IN THE NORTH.
SKIES WILL CLEAR OUT OVERNIGHT AS HIGH PRESSURE MOVES IN FROM THE
SOUTHWEST. CANNOT RULE OUT THE CHANCE FOR SOME FOG TO FORM OVERNIGHT
IF LOW LEVEL INVERSION SETS UP AS INDICATED BY THE NAM.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL KEEP CONDITIONS DRY THURSDAY AND THURSDAY NIGHT.
WEAK FRONT WILL PASS THE REGION FRIDAY...BUT MODELS SHOW THAT
SOUTHERNMOST EXTENT OF PRECIPITATION SHOULD REMAIN ALONG THE I-80
CORRIDOR. HAVE KEPT PREVIOUS FORECAST OF SLIGHT CHANCE POPS NORTH OF
THE INTERSTATE. LITTLE CHANGE EXPECTED IN WEATHER FOR SATURDAY.
TEMPERATURES WILL WARM BY 2-3 DEGREES EACH DAY...GOING A FEW DEGREES
ABOVE NORMAL BY SATURDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODEL TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO
APPROACH THE REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A
SERIES OF SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL
TROUGH AND ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO
SINK SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS
COULD ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO
TUESDAY BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE
PERIOD AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THROUGH THIS
AFTERNOON, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
825 AM EST WED NOV 30 2011
.SYNOPSIS...
RAIN AND SNOW SHOWERS WILL DIMINISH TODAY AS LOW PRESSURE MOVES OFF
TO THE NORTHEAST. BELOW NORMAL TEMPERATURES WILL PERSIST INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
8AM UPDATE...
ONLY CHANGE WAS TO ADD DRIZZLE...AS MODEL PROFILES SHOW CLOUD
TOPS GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION EARLY TODAY.
THAT WILL CHANGE AS WINDS BECOME MORE WESTERLY LATER THIS
MORNING... EXPECTTHAT COVERAGE OF PRECIPITATION SHOULD PICK UP.
SYNOPTIC MODELS GENERALLY SHOW A FEW HUNDREDTHS OF PRECIPITATION
IN ALL LOCATIONS THROUGH THE MORNING...BUT ALL HI- RES MODELS
INDICATE THAT THE DEFORMATION ZONE CURRENTLY OVER NORTHWEST OHIO
WILL SIMPLY SLIDE NORTHEAST...POSSIBLY CLIPPING SOME EASTERN OHIO
AND NORTHWEST PA COUNTIES. WITH SUCH STRONG AGREEMENT FROM THE HI-
RES MODELS...WILL TRUST THEM FOR THE FIRST 6-12 HOURS OF THE
FORECAST. WILL STILL INCLUDE SOME UPSLOPE SHOWERS ALONG THE RIDGES
AS WELL. AS FOR P-TYPE...CURRENT IR SATELLITE IMAGES SHOW ONLY
SCATTERED COVERAGE OF CLOUD TOP TEMPERATURES COLDER THAN
-10C...AND MODEL SOUNDINGS INDICATE THAT CLOUD TOPS SHOULD REMAIN
BETWEEN -10C AND 0C. IF THIS HOLDS...THEN LITTLE ICE CRYSTAL
GROWTH WOULD BE EXPECTED AND WITH SURFACE TEMPERATURES IN MOST
LOCATIONS REMAINING ABOVE FREEZING...PRECIP SHOULD FALL AS DRIZZLE
OR LIGHT RAIN. ALONG THE RIDGES...SOME FREEZING DRIZZLE COULD MIX
IN WITH SNOW SHOWERS. PRECIP WILL DIMINISH QUICKLY DURING THE
AFTERNOON HOURS. EXPECT LITTLE RISE IN TEMPERATURES DURING THE DAY
WITH COLDER AIR FILTERING IN. WINDS WILL ALSO BE A BIT
GUSTY...RANGING FROM 20 MPH IN THE SOUTH TO 30 MPH IN THE NORTH.
SKIES WILL CLEAR OUT OVERNIGHT AS HIGH PRESSURE MOVES IN FROM THE
SOUTHWEST. CANNOT RULE OUT THE CHANCE FOR SOME FOG TO FORM OVERNIGHT
IF LOW LEVEL INVERSION SETS UP AS INDICATED BY THE NAM.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL KEEP CONDITIONS DRY THURSDAY AND THURSDAY NIGHT.
WEAK FRONT WILL PASS THE REGION FRIDAY...BUT MODELS SHOW THAT
SOUTHERNMOST EXTENT OF PRECIPITATION SHOULD REMAIN ALONG THE I-80
CORRIDOR. HAVE KEPT PREVIOUS FORECAST OF SLIGHT CHANCE POPS NORTH OF
THE INTERSTATE. LITTLE CHANGE EXPECTED IN WEATHER FOR SATURDAY.
TEMPERATURES WILL WARM BY 2-3 DEGREES EACH DAY...GOING A FEW DEGREES
ABOVE NORMAL BY SATURDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODEL TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO
APPROACH THE REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A
SERIES OF SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL
TROUGH AND ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO
SINK SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS
COULD ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO
TUESDAY BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE
PERIOD AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THIS
MORNING, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
306 AM EST WED NOV 30 2011
.SYNOPSIS...
RAIN AND SNOW SHOWERS WILL DIMINISH TODAY AS LOW PRESSURE MOVES OFF
TO THE NORTHEAST. BELOW NORMAL TEMPERATURES WILL PERSIST INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE EARLY MORNING HOURS...FORECAST AREA IS GENERALLY
SURROUNDED BY LIGHT PRECIPITATION...WITH LITTLE ACTUALLY OCCURRING
IN THE FORECAST AREA ITSELF. AS WINDS BECOME MORE WESTERLY BY
DAWN...EXPECT THAT COVERAGE OF PRECIPITATION SHOULD PICK UP.
SYNOPTIC MODELS GENERALLY SHOW A FEW HUNDREDTHS OF PRECIPITATION IN
ALL LOCATIONS THROUGH THE MORNING...BUT ALL HI-RES MODELS INDICATE
THAT THE DEFORMATION ZONE CURRENTLY OVER NORTHWEST OHIO WILL SIMPLY
SLIDE NORTHEAST...POSSIBLY CLIPPING SOME EASTERN OHIO AND NORTHWEST
PA COUNTIES. WITH SUCH STRONG AGREEMENT FROM THE HI-RES
MODELS...WILL TRUST THEM FOR THE FIRST 6-12 HOURS OF THE FORECAST.
WILL STILL INCLUDE SOME UPSLOPE SHOWERS ALONG THE RIDGES AS WELL. AS
FOR P-TYPE...CURRENT IR SATELLITE IMAGES SHOW ONLY SCATTERED
COVERAGE OF CLOUD TOP TEMPERATURES COLDER THAN -10C...AND MODEL
SOUNDINGS INDICATE THAT CLOUD TOPS SHOULD REMAIN BETWEEN -10C AND
0C. IF THIS HOLDS...THEN LITTLE ICE CRYSTAL GROWTH WOULD BE EXPECTED
AND WITH SURFACE TEMPERATURES IN MOST LOCATIONS REMAINING ABOVE
FREEZING...PRECIP SHOULD FALL AS DRIZZLE OR LIGHT RAIN. ALONG THE
RIDGES...SOME FREEZING DRIZZLE COULD MIX IN WITH SNOW SHOWERS.
PRECIP WILL DIMINISH QUICKLY DURING THE AFTERNOON HOURS. EXPECT
LITTLE RISE IN TEMPERATURES DURING THE DAY WITH COLDER AIR FILTERING
IN. WINDS WILL ALSO BE A BIT GUSTY...RANGING FROM 20 MPH IN THE
SOUTH TO 30 MPH IN THE NORTH.
SKIES WILL CLEAR OUT OVERNIGHT AS HIGH PRESSURE MOVES IN FROM THE
SOUTHWEST. CANNOT RULE OUT THE CHANCE FOR SOME FOG TO FORM OVERNIGHT
IF LOW LEVEL INVERSION SETS UP AS INDICATED BY THE NAM.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL KEEP CONDITIONS DRY THURSDAY AND THURSDAY NIGHT.
WEAK FRONT WILL PASS THE REGION FRIDAY...BUT MODELS SHOW THAT
SOUTHERNMOST EXTENT OF PRECIPITATION SHOULD REMAIN ALONG THE I-80
CORRIDOR. HAVE KEPT PREVIOUS FORECAST OF SLIGHT CHANCE POPS NORTH OF
THE INTERSTATE. LITTLE CHANGE EXPECTED IN WEATHER FOR SATURDAY.
TEMPERATURES WILL WARM BY 2-3 DEGREES EACH DAY...GOING A FEW DEGREES
ABOVE NORMAL BY SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
MODEL TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO
APPROACH THE REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A
SERIES OF SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL
TROUGH AND ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO
SINK SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS
COULD ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO
TUESDAY BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE
PERIOD AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THIS
MORNING, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
101 AM EST WED NOV 30 2011
.SYNOPSIS...
SNOW SHOWERS CAN BE EXPECTED OVERNIGHT AND WEDNESDAY AS COLDER
AIR MOVES OVER THE UPPER OHIO VALLEY IN THE WAKE OF TODAYS FRONTAL
PASSAGE. DRY WEATHER AND SEASONAL TEMPERATURES ARE FORECAST FOR
THE LATTER PART OF THE WEEK AS HIGH PRESSURE BUILDS.
&&
.NEAR TERM /THROUGH TODAY/...
EXCEPT FOR RADAR RETURNS ALONG THE PENNSYLVANIA RIDGES...RADAR
RETURNS HAVE REALLY DIED OFF ACROSS THE FORECAST AREA. PRIMARY
CHANGE WITH THE 06Z UPDATE WAS TO BACK OFF ON POPS IN THE NEAR
TERM...BUT STILL THINK THAT LIKELY POPS ARE WARRANTED FOR ALL
LOCATIONS JUST BEFORE SUNRISE AS UPPER LOW MOVES NORTHEAST AND
DEFORMATION ZONE APPROACHES FROM THE WEST. PREVIOUS DISCUSSION
FOLLOWS.
LATE EVE UPDATE ISSUED TO ACCOUNT FOR LATEST TRENDS AS PER RADAR
AND OBS. COLDER AIR WAS SWEEPING ACROSS OHIO TONIGHT UNDER ADVNG
MID/UPR LOW PRESSURE. THAT COLDER AIR...ALONG WITH SOME RAIN AND
SNOW SHOWERS...WL AFFECT THE REGION TONIGHT AS THE LOW PROGRESSES
NEWD. WITH TEMPERATURES REMAINING ABOVE FREEZING FOR THE MOST
PART...LIGHT ACCUMULATION SHOULD BE CONFINED TO GRASSY AREAS. THE
EXCEPTION WL BE FOR THE RIDGES WHERE A GENERAL ONE TO THREE
INCHES LOOKS REASONABLE BEFORE LOWERING INVERSION SUPPRESSES THE
SNOW SHOWERS ON WEDNESDAY.
COLD ADVECTION UNDER THE PASSING TROUGH ALOFT SUPPORTS CONTD SNOW
SHOWERS ON WEDNESDAY WITH CATEGORICAL POP NUMBERS FORECAST OVR
AREAS FM I 80 NWD. RELATIVELY WARM BOUNDARY LAYER TEMPS SHOULD
PRECLUDE ANY SIGNIFICANT ACCUMULATION.
TEMPERATURES WERE FORECAST USING NAM GUIDANCE AND SHOULD AVERAGE
OUT CLOSE TO NORMAL FOR THE NEAR TERM.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
HIGH PRESSURE IS PROJECTED TO BEGIN BUILDING OVR THE UPR OH REGION
ON WED NGT...HENCE SNOW SHOWER CHANCES WERE REDUCED MORE RAPIDLY
THAN PREVIOUS PROGS WITH DRY WEATHER CONTD THROUGH THURSDAY. THERE
ARE A FEW MODEL TIMING ISSUES WITH THE WEAK OPEN SHORTWAVE DROPPING
THROUGH THE GREAT LAKES ON FRIDAY. KEPT CLOSER TO THE 00Z/12Z
GFS/ECMWF SINCE THE NAM SEEMS TO BE SLOWER. REGARDLESS..WITH LITTLE
MOISTURE ASSOCIATED WITH THE SYSTEM...NOT MUCH MORE THAN A WIND
SHIFT AND A BRIEF DIP IN TEMPERATURES IS EXPECTED. KEPT SLIGHT
CHANCE POPS FOR THE COUNTIES NORTH OF I-80 WITH SNOW FLURRIES
POSSIBLE TOWARDS EVENING.
ALTHOUGH THERE WILL BE A SLIGHT MODERATION IN TEMPS DURING THE
SHORT TERM PERIOD...READINGS WERE FORECAST CLOSE TO NORMAL USING
GUIDANCE BLEND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AFTER THE AFOREMENTIONED DISTURBANCE PASSES FRIDAY...HIGH PRESSURE
WILL ONCE AGAIN BUILD OVER THE REGION FOR THE WEEKEND. MODEL
TIMING ISSUES EXIST WITH THE NEXT SYSTEM PROGGED TO APPROACH THE
REGION LATE SUNDAY. CURRENTLY MODELS INDICATE A SERIES OF
SHORTWAVES DEEPENING THE POSITIVELY TILTED UPPER LEVEL TROUGH AND
ALLOWING FOR VERY COLD H850 TEMPERATURES OVER CANADA TO SINK
SOUTHWARD TO AS FAR AS MISSISSIPPI VALLEY BY TUESDAY. THIS COULD
ALLOW FOR WIDESPREAD SNOW SHOWERS OVERNIGHT MONDAY INTO TUESDAY
BUT GENERALLY KEPT POPS IN THE CHANCE CATEGORY THROUGH THE PERIOD
AT THIS TIME DUE TO UNCERTAINTY. WITH THE H850 TEMPERATURES
REACHING -12C AND NORTHWEST FLOW...HIGH TEMPERATURES COULD BE 10
DEGREES BELOW NORMAL TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND RADAR DATA AND HRRR AND NAM MODEL OUTPUT,
EXPECT POST SYSTEM TROWAL-RELATED/SO-CALLED WRAP AROUND/ MVFR
STRATOCUMULUS AND LIGHT PRECIPITATION TO AFFECT THE UPPER OHIO
VALLEY INTO LATE AFTERNOON. BRIEF IFR RESTRICTIONS MAY OCCUR THIS
MORNING, BUT LACK SUFFICIENT CONFIDENCE TO PINPOINT ITS OCCURRENCE.
EXPECT PRECIPITATION TYPE TO BE MAINLY DRIZZLE, ALBEIT BRIEF SNOW
FLURRIES CANNOT BE RULED OUT. NAM MODEL PROFILES SHOW CLOUD TOPS
GENERALLY NOT COLD ENOUGH FOR ICE NUCLEATION. HOWEVER, RECENT
SATELLITE DATA DOES SHOW SOME HIGHER COLDER CLOUDS PASSING OVER
THE SHALLOW WARMER CLOUDS, SO SOME SEEDER FEEDER ICE NUCLEATION
MAY OCCUR THIS MORNING.
FAST FLOW ALOFT WILL MIX DOWN TO PROMOTE SURFACE WIND GUSTS OF 25
KTS TODAY. WINDS WILL SUBSIDE AT SUNDOWN, WHEN REMAINING CLOUD
CEILINGS WILL LIKEWISE DISSIPATE.
OUTLOOK...THURSDAY THROUGH SUNDAY....
MAINLY VFR. ONLY POTENTIAL FOR RESTRICTIONS CAN BE EARLY MORNING FOG
THURSDAY RELATED TO A SHALLOW SURFACE TEMPERATURE INVERSION, AND
POSSIBLE SHOWERS NEAR I-80 FRIDAY NIGHT WITH A COLD FRONT PASSING
THROUGH THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 PM EST THU DEC 1 2011
UPDATED FOR 00Z AVIATION DISCUSSION
.SHORT TERM...
FOR TONIGHT...LOW PRESSURE TROUGH RESPONSIBLE FOR LAST NIGHT AND
TODAYS SNOWFALL WILL MAKE ITS WAY FROM EASTERN UPPER MICHIGAN TO
QUEBEC OVERNIGHT. MEANWHILE...A RIDGE EXTENDING FROM HIGH PRESSURE
IN THE CENTRAL PLAINS WILL SETTLE IN OVER UPPER MICHIGAN...BRINGING
QUIETER CONDITIONS TO A MAJORITY OF THE CWA. MAIN CONCERN IS WHETHER
OR NOT LES WILL CONTINUE TO IMPACT EASTERN UPPER MICHIGAN THROUGH
THE NIGHT WITH THE INCOMING DRY AIR. AS OF 15Z...CONDITIONS ACROSS
MINNESOTA WERE DRYING OUT...WITH CLEAR SKIES AND LARGE DEWPOINT
DEPRESSIONS OBSERVED. 12Z SOUNDINGS AT INTERNATIONAL FALLS MN AND
PICKLE LAKE ONTARIO SHOW INVERTED V-TYPE SOUNDINGS...WITH INVERSION
HEIGHTS AROUND 3000 FEET. THIS DRYING WITH LOW INVERSION HEIGHTS
SUGGESTS THAT ANY LES ACCUMULATIONS OVERNIGHT IN THE EASTERN CWA
WILL BE SMALL...AND COVERAGE WILL BE LIMITED. CURRENTLY MOST CLOUD
COVER IS DIMINISHING ACROSS THE WESTERN CWA...WITH THE EXCEPTION OF
LAKE EFFECT CLOUDS. REGWRF...RUC...AND GFS ALL HINT AT A COUPLE OF
LES BANDS DEVELOPING EAST OF MARQUETTE...MOVING TOWARDS GRAND MARAIS
AND LASTING THROUGH THE NIGHT. SOME CLOUD BANDS ARE OBSERVED ON THE
VISIBLE SATELLITE AT THE MOMENT OVER EASTERN LAKE SUPERIOR...AND I
EXPECT THESE TO BECOME MORE ORGANIZED AFTER DARK. THE MAIN
DIFFERENCE OBSERVED BETWEEN EACH OF THE MODEL FIELDS IS THE AMOUNT
OF LINGERING MOISTURE...THE NAM PUSHES ALL OF THE MOISTURE OUT OF
THE REGION BY 00Z TONIGHT...WHICH PUTS THE END TO LES. THIS SEEMS TO
BE THE OUTLIER...HOWEVER. WITH THE WINDS OUT OF THE NORTHWEST THIS
EVENING...EXPECT SOME LIGHT LAKE EFFECT SNOW SHOWERS TO CONTINUE
FROM MARQUETTE MOVING EASTWARD THROUGH THE NIGHT AS THE DRIER AIR
WORKS IN. ANOTHER FAVORABLE FACTOR IS THAT LES TYPICALLY RAMPS UP
DURING THE NIGHT HOURS...AND AS A RESULT WILL KEEP IN SOME SHOWERS
EAST OF MARQUETTE. THIS LES SHOULD END BY EARLY MORNING HOWEVER...AS
WINDS BECOME WESTERLY...PUSHING ANY REMAINING BANDS INTO ONTARIO OR
ENDING THEM ALL TOGETHER. FOR THE WESTERN CWA ONLY HAVE LAKE INDUCED
CLOUD COVER LASTING THROUGH AROUND 6Z AS A RESULT OF THE NORTHWEST
WINDS...THEN TAPERING OFF AS THE WINDS SHIFT TO THE SOUTHWEST. CLOUD
COVER IN THE INTERIOR WEST TONIGHT...ALLOWING FOR DECENT RADIATIONAL
COOLING. AS A RESULT...TEMPERATURES NEAR THE WISCONSIN BORDER SHOULD
FALL INTO THE SINGLE DIGITS TONIGHT.
AS FOR FRIDAY...WITH THE HIGH PRESSURE RIDGE OVERHEAD AND THE DRY
AIRMASS IN PLACE...EXPECT A MOSTLY SUNNY DAY. TEMPERATURES WILL
STRUGGLE TO REACH INTO THE 30S INLAND AS A RESULT OF MORE STABLE
CONDITIONS. EXPECT WINDS TO INCREASE THROUGHOUT THE DAY AS PRESSURE
GRADIENT BETWEEN HIGH PRESSURE RIDGE AND A LOW PRESSURE SYSTEM
CENTERED OVER MANITOBA TIGHTENS.
.LONG TERM 00Z SAT ONWARD...
THE NAM SHOWS A 500 MB SHORTWAVE RIDGE OVER THE UPPER GREAT LAKES
00Z SAT WITH A TROUGH IN THE NORTHERN ROCKIES AND A CLOSED LOW AND
TROUGH IN THE DESERT SW 00Z SAT. THE TROUGH PULLS EAST INTO THE
NORTHERN PLAINS 00Z SUN WITH THE SOUTHERN TROUGH GETTING CUT OFF AND
REMAINING IN THE DESERT SW. NAM SHOWS SOME 850-500 MB Q-VECTOR
CONVERGENCE AND MOISTURE SAT INTO SUN MORNING. NAM ALSO SHOWING SOME
ISENTROPIC LIFT AND MOISTURE ON I280K-I295K SURFACES ON SAT BEFORE
THE LIFT MOVES OFF FOR SAT NIGHT INTO SUNDAY. GFS SHOWS SOME 850-500
MB Q-VECTOR CONVERGENCE MOVING THROUGH FRI NIGHT THROUGH SAT EVENING
BEFORE THIS MOVES OUT. STILL LOOKS LIKE A 3-6 INCH SNOW EVENT FOR
THE CWA WITH THE MOST SNOW IN THE CENTRAL CWA AND LESSER AMOUNTS IN
THE WEST AND EAST. THE EAST WOULD HAVE SOME RAIN MIXED IN AND THE
WEST WOULD BE ON THE WESTERN EDGE OF THE PCPN SHIELD. LAKE EFFECT
THEN TAKES OVER ON SUNDAY FOR NORTH AFFECTED LAKE EFFECT SNOW BELTS.
OVERALL DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES OR WEATHER.
IN THE EXTENDED...THE GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
NORTHERN PLAINS 00Z MON DOWN INTO THE SOUTHERN ROCKIES. THIS TROUGH
MOVES INTO THE UPPER GREAT LAKES 00Z TUE. THIS TROUGH THEN SPLITS
WITH THE NORTHERN PART OF THE TROUGH OVER THE LOWER GREAT LAKES
WHILE THE SOUTHERN PART IS OVER THE SOUTHERN PLAINS 00Z WED. A BROAD
TROUGH THEN SETS UP ACROSS THE NORTHERN U.S. 00Z THU ASSOCIATED WITH
THE CIRCUMPOLAR VORTEX OVER CENTRAL AND NORTHERN CANADA WITH THE
TROUGH AXIS REMAINING OFF TO THE WEST OF THE AREA 00Z FRI. WHAT THIS
WILL MEAN IS COLDER WEATHER IS ON THE WAY WITH LAKE EFFECT SNOW
BEING THE MAIN WEATHER TYPE FOR THIS FORECAST AND COLDER THAN NORMAL
TEMPERATURES. 850 MB TEMPERATURES GET DOWN TO -14C ON MONDAY INTO
TUESDAY WITH THE GFS WITH A WARMUP FOR WED...BEFORE A REINFORCING
SHOT OF COLD AIR ARRIVES FOR THU AS A COLD FRONT MOVES THROUGH.
OVERALL...DID NOT CHANGE MUCH EXCEPT TO BUMP UP POPS ON THURSDAY IN
LAKE EFFECT AREAS WITH THE COLDER AIR.
&&
.AVIATION /FOR 00Z TAF ISSUANCE/
SATELLITE INDICATED THAT THE BACK EDGE OF THE HIGH END MVFR CLOUD
DECK WAS ALONG THE LAKE SUPERIOR SHORLINE OF WRN UPPER MI INTO THE
KEWEENAW. ENOUGH INSTABILITY LINGERED WITH 900 MB TEMPS NEAR -11C TO
SUSTAIN THE LAKE CLOUDS THIS EVENING. RUC 925-900 MB RH FCST AND
RECENT TRENDS SUGGEST THAT CLEARING WILL BE SLOW TO ADVANCE THIS
EVENING...KEEPING KIWD/KCMX NEAR THE EDGE OF THE CLOUD AREA...BUT
SHOULD PROGRESS INTO CNTRL UPPER MI BY AROUND 06Z AS LOW LEVEL WINDS
BACK MORE WRLY. VFR CONDITIONS SHOULD THEN PREVAIL THE REST OF THE
NIGHT INTO FRI.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
HIGH PRESSURE RIDGE OVER LAKE SUPERIOR WILL KEEP CONDITIONS ON THE
LAKE QUIET OVERNIGHT...WITH FLOW BEING GENERALLY NORTHWEST. AS THE
RIDGE MOVES OUT...A LOW PRESSURE SYSTEM CENTERED OVER MANITOBA WILL
DRAG A TROUGH ACROSS LAKE SUPERIOR. AS IT PROGRESSES EASTWARD...THE
PRESSURE GRADIENT WILL STRENGTHEN. AS A RESULT...GALES TO 35-40
KNOTS ARE EXPECTED ON THE LAKE FROM FRIDAY THROUGH SATURDAY MORNING.
WESTERN LAKE SUPERIOR NEAR ISLE ROYALE AND NORTH CENTRAL LAKE
SUPERIOR WILL SEE THE START OF THE GALES FRIDAY AFTERNOON...AND ON
FRIDAY NIGHT THE EASTERN ZONES. ALL OF THE GALE FORCE WINDS SHOULD
END BY SATURDAY MORNING. WINDS WILL CONTINUE TO GUST TO AROUND 30
KNOTS SATURDAY AFTERNOON...BEFORE DECREASING TO LESS THAN 20 KNOTS
FOR THE REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM FRIDAY TO 10 AM EST SATURDAY FOR LSZ266-
267.
GALE WARNING FROM 10 AM FRIDAY TO 7 AM EST SATURDAY FOR LSZ263-
264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MCB
LONG TERM...07
AVIATION...MCB
MARINE...MCB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
312 PM CST WED NOV 30 2011
.DISCUSSION...
TONIGHT THROUGH THURSDAY...AT THE SFC A WEAK COLD FRONT WILL
SLOWLY GLIDE S ACRS SRN MN/SW WI THROUGH THE OVERNIGHT HOURS INTO
THU MRNG. AS IT DROPS S...A RELATIVELY WEAK AREA OF LOW PRESSURE
IS EXPECTED TO DEVELOP ALONG IN INVOF MN/IA BORDER. FAIRLY DEEP
MOISTURE...AS SHOWN BY AN EXTENSIVE CLOUD SHIELD ON VIS SAT
IMAGERY AND RATHER MOIST RUC SOUNDINGS...IS AVAILABLE FOR A DECENT
MIDLVL SHORTWAVE TROUGH AXIS TO PRODUCE PRECIP MAINLY AFTER
MIDNIGHT AND THROUGH SUNRISE. TAKING THE FORM OF ALL SNOW... WILL
LOOK FOR ENOUGH QPF TO PRODUCE ONE HALF TO ONE AND A HALF INCHES
OF SNOW WITH THE HEAVIEST OF THE SNOW OCCURRING DURING THE MORNING
COMMUTE HOURS. THE GREATER OF THE SNOW ACCUMULATIONS WILL EAST AND
SOUTH OF THE TWIN CITIES METRO. ALTHOUGH CONVECTIVE SNOWS ARE NOT
APPARENT ON EVEN SHORT-TERM MODELS PARTICULARLY WITH SFC
CONVERGENCE AND LIFT RATHER WEAK...THE UPPER LEVEL SUPPORT
AVAILABLE DOES NOT RULE OUT AN ISOLATED BURST OF HEAVIER SNOW THAT
COULD PRODUCE UP TO 2 INCHES IN A SHORT AMOUNT OF TIME...MAINLY
OVER WRN WI WHERE JET DYNAMICS LOOK TO POTENTIALLY ENHANCE PRECIP
THURSDAY MORNING. THE PRECIP WILL GRADUALLY TAPER OFF DURING THE
LATE MORNING THROUGH AFTERNOON HOURS TOMORROW WITH VERY LITTLE
LEFT BY LATE AFTERNOON. AS FOR TEMPERATURES...THE POTENT COLD
FRONT WILL EFFICIENTLY LEAD THE WAY FOR H85 TEMPS IN THE -7 TO -10
DEG C RANGE TO DROP THROUGH THE REGION DURING THE DAY TOMORROW...
MAKING FOR A VERY SMALL DIURNAL RANGE FROM LOW TEMPS TONIGHT TO
HIGHS TMRW. LOWS TONIGHT WILL RANGE FROM THE LWR 20S NW TO AROUND
30 SE AND IN THE METRO...FOLLOWED BY HIGHS THU FROM THE MID 20S NW
TO THE LWR 30S SE.
THURSDAY NIGHT THROUGH SUNDAY...SKIES WILL SLOWLY CLEAR OUT THU
NIGHT INTO FRI THE UPPER LEVEL TROUGH DROPS S OF THE REGION AND A
BUBBLE HIGH PRES RIDGE MOVES ACROSS THE NRN PLAINS INTO THE GREAT
LAKES. AT THE SFC...A SPOKE OF HIGH PRES EXTENDING NE FROM THE
CENTRAL PLAINS WILL ROTATE THROUGH...ALLOWING FOR DECENT
RADIATIONAL COOLING CONDITIONS THU NIGHT AS WINDS DROP TO BELOW 7
MPH. LOWS WILL FALL TO THE UPPER SINGLE DIGITS TO THE MID TEENS.
EVEN WITH THE CLEAR SKIES CONTINUING ON FRI AND SFC FLOW TURNING
MORE SLY...NW TO W UPPER FLOW AND H85 TEMPS ARND -5 DEG C WILL
KEEP HIGHS ON FRI JUST BELOW FREEZING. THE WEATHER STORY BECOMES
VERY INTERESTING FRI NIGHT THROUGH SAT NIGHT AS AS UPPER LEVEL LOW
CHURNING IN THE SOUTHWEST BECOMES CAUGHT UP IN A NORTHERN STREAM
LONGWAVE TROUGH AXIS PUSHING THRU WRN CANADA AND THE NRN PLAINS
STATES. BOTH UPPER SYSTEMS INTERACT BUT IN PIECES...AND A FEW
PIECES OF ENERGY WILL SHIFT NE FROM THE SOUTHWEST TWD THE GREAT
LAKES SAT AS CYCLOGENESIS OCCURS OVER THE TX PANHANDLE. THIS
NEWLY-GENERATED SFC LOW WILL RACE NE LATE SATURDAY THROUGH SAT
NIGHT BUT THE BIGGER PROBLEM IS HOW CLOSE AN UPPER SHORTWAVE
TROUGH AXIS COMES TO INTERACT WITH IT. MOISTURE TRANSPORT AHEAD OF
THIS NEW SFC LOW INCREASES AND THE INCOMING UPPER TROUGH WILL
ENHANCE LIFT. GIVEN THE COLD TEMPERATURES IN PLACE...P-TYPE ISSUES
WILL NOT BE PRESENT FOR THE WFO MPX CWFA AS PRECIP WOULD BE ALL
SNOW. THERE IS STILL MUCH MODEL DISAGREEMENT IN THE PLACEMENT OF
THE MAIN PLAYERS INVOLVED...AND THIS IS RELAYED VIA MODEL SNOWFALL
ACCUMS WHICH COULD BE UP TO A COUPLE OF INCHES TO OVER 6 INCHES
WITH THE HIGHEST AMOUNTS FOR SOUTHERN AND EASTERN PORTIONS OF THE
COVERAGE AREA. HAVE NUDGED POPS INTO THE LIKELY CATEGORY FOR THOSE
AREAS...TRENDING DOWN GOING WEST AND NORTH...AND HAVE KEPT
SNOWFALL AMOUNTS CAPPED AT 4 INCHES FOR FAR SRN AND ERN FRINGES
WITH NO SNOW EXPECTED FOR THE NWRN TIERS. THIS SYSTEM QUICKLY
EJECTS TO THE E SAT NIGHT INTO SUN...ALLOWING FOR AT LEAST PARTIAL
CLEARING DURING THE DAY SUNDAY BEFORE ANOTHER AREA OF LOW PRESSURE
DROPS IN FROM MANITOBA LATE SUN INTO SUN NIGHT. THERE IS POTENTIAL
FOR VERY LIGHT ACCUMS OVER NRN TIERS OF THE COVERAGE AREA BUT WITH
SO MUCH UNCERTAINTY WITH THIS SATURDAY SYSTEM...IT IS DIFFICULT TO
PINPOINT THINGS WITH THE LATE SUNDAY SYSTEM SO HAVE KEPT POPS IN
THE SLGT CHC CATEGORY. TEMPERATURES WILL RUN NEAR TO SLIGHTLY
ABOVE NORMAL THRU FRI...THEN DROP TO SLIGHTLY BELOW NORMAL OVER
THE WEEKEND.
MONDAY THROUGH WEDNESDAY...THE AFOREMENTIONED LOW ON SUNDAY WILL
MOVE INTO THE GREAT LAKES MONDAY...FOLLOWED BY RIDGING BOTH AT THE
SFC AND ALOFT FOR THE START OF NEXT WEEK. COLDER PUNCHES OF AIR
DROPPING S FROM NRN-CENTRAL CANADA WILL KEEP TEMPS BELOW NORMAL
FOR THE FIRST HALF OF NEXT WEEK. HAVE KEPT A PREDOMINANTLY DRY
FORECAST GOING DUE TO THE LACK OF BONA FIDE SYSTEMS PROGGED FOR
THIS PERIOD.
&&
.AVIATION.../18Z TAF ISSUANCE/
A BUSIER FORECAST PERIOD IS IN STORE FOR AVIATION CONCERNS IN
COMPARISON TO THE PAST MANY DAYS. AN SHORTWAVE TROUGH CURRENTLY
MOVING THROUGH THE NORTHERN ROCKIES WILL SWING ACROSS THE NORTHERN
PLAINS AND UPPER MIDWEST LATER TODAY AND TONIGHT... PUSHING A COLD
FRONT ACROSS OUR AREA TONIGHT INTO EARLY THURSDAY. A BAND OF LIGHT
TO MODERATE PCPN IS EXPECTED TO ACCOMPANY THE PASSAGE OF THESE
SYSTEMS... WITH MORE WIDESPREAD PCPN DEVELOPING AS THE SYSTEM
MOVES SOUTHEAST THROUGH THE AREA AND THE ATMOSPHERE HAS MORE TIME
TO SATURATE. A LOWERING IN CEILINGS WILL CONTINUE THIS AFTERNOON
INTO TONIGHT... WITH MVFR CONDITIONS LIKELY DEVELOPING PRIOR TO
PCPN ARRIVAL... AND LOWER MVFR AND POSSIBLE IFR CEILINGS DURING
THE PCPN. MOST PCPN SHOULD BE IN THE FORM OF SNOW... ALTHOUGH SOME
MIX WITH RAIN OR FREEZING DRIZZLE IS POSSIBLE OVER THE
NORTHWESTERN PORTION OF THE FORECAST AREA AT THE ONSET. HOWEVER...
THAT POSSIBILITY IS SUFFICIENTLY LOW TO LEAVE IT OUT OF THE
FORECAST FOR THAT AREA. CONDITIONS SHOULD IMPROVE FAIRLY QUICKLY
IN THE WAKE OF THE SYSTEM TOMORROW MORNING... WITH VFR CONDITIONS
DEVELOPING BY MID TO LATE MORNING ACROSS MOST OF THE AREA.
KMSP... TAF REFLECTS EXPECTATIONS OF THE EVOLUTION OF CEILINGS AND
VISIBILITIES GOING FROM VFR TO MVFR WITH SOME IFR POSSIBLE. SHOULD
GET A BETTER HANDLE ON THE POSSIBILITY OF LOWER CEILINGS AND/OR
VISIBILITIES ONCE THINGS START TO COME TOGETHER UPSTREAM LATER
THIS AFTERNOON AND THIS EVENING. TIMING UNCERTAINTY ON THE WORST
CONDITIONS COULD VARY BY +/- 1-3 HOURS... WITH SOME POSSIBILITY OF
SUB-1000FT CEILINGS AND SUB 1 MILE VISIBILITIES... PARTICULARLY
BETWEEN 09Z AND 12Z.
//OUTLOOK FOR KMSP FOR THURSDAY NIGHT THROUGH SUNDAY//
THURSDAY NIGHT...VFR CONDITIONS EXPECTED.
FRIDAY...VFR CONDITIONS EXPECTED.
FRIDAY NIGHT...VFR CONDITIONS EXPECTED.
SATURDAY...MVFR CEILINGS POSSIBLE. CHANCE OF SNOW LATE.
SATURDAY NIGHT...MVFR CEILINGS EXPECTED... IFR CEILING POSSIBLE.
MVFR VISIBILITIES POSSIBLE. CHANCE OF SNOW.
SUNDAY...MVFR CEILINGS POSSIBLE EARLY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC/TRH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
346 PM EST WED NOV 30 2011
.SYNOPSIS...
A NORTHWEST FLOW OF COOLER AIR LATE THIS AFTERNOON WILL BRING
SCATTERED RAIN AND SNOW SHOWERS TO THE AREA TIL EARLY EVENING.
HIGH PRESSURE WILL BUILD INTO THE REGION LATE TONIGHT AND REMAIN
IN THE VICINITY THROUGH THURSDAY NIGHT. A WEAK COLD FRONT IS
EXPECTED TO CROSS THE AREA ON FRIDAY BRINGING THE NEXT CHANCE FOR
RAIN AND POSSIBLY SNOW SHOWERS.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
H5 TROF AND ASSOCIATED SFC FEATURE WILL MOVE EAST OF THE REGION
BY EARLY EVENING. SCATTERED RAIN/SNOW SHOWERS WILL CONTINUE
PRIMARILY ACROSS THE NRN CWA TIL EARLY EVENING. CONDITIONS
OVERNIGHT NOT FAVORABLE FOR LAKE EFFECT PRECIP DUE TO MID LEVEL
WARMING BEGINNING AT 00Z ALONG WITH VERY DRY AIRMASS UPSTREAM.
ALTHOUGH NORTHWEST FLOW MAY KEEP SKIES PARTLY CLOUDY ACROSS MUCH
OF CENTRAL NEW YORK UNTIL DAYBREAK.
OVERNIGHT LOWS WILL RANGE FROM THE MID 20S TO AROUND 30.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY THROUGH THURSDAY NIGHT...SFC HIGH PRES WILL STRETCH FROM
THE TN VALLEY NORTHEAST INTO NEW ENGLAND BRINGING MAINLY CLEAR
SKIES TO THE REGION ALONG WITH TEMPS NEAR SEASONAL LEVELS.
FRIDAY...WEAK NORTHERN STREAM MOISTURE STARVED SFC TROF WILL DROP
ACROSS THE REGION BRINGING THE CHANCE FOR RAIN SHOWERS ESPECIALLY
OVER THE NRN PTN OF THE CWA. BOUNDARY LAYER TEMPS BY LATE
AFTERNOON MAY BE COLD ENOUGH FOR A RAIN/SNOW SHOWER MIX. MAXES
WILL GENERALLY RANGE IN THE LOWER TO MIDDLE 40S.
FRIDAY NIGHT...ONCE AGAIN EVEN BEHIND A SFC TROF CONDITIONS ARE
NOT FAVORABLE FOR LAKE EFFECT SNOW. SFC HIGH PRES BUILDS IN
QUICKLY BEHIND THE FRONT RESULTING IN VERY WEAK FLOW ALONG WITH MODERATING
T85 DURING THE OVERNIGHT PERIOD. SKIES WILL BECOME MAINLY CLEAR TO
PARTLY CLOUDY WITH LOWS IN THE MID TO UPPER 20S.
SATURDAY...A STRONG UPPER LEVEL RIDGE BUILDS OVER THE NORTHEAST,
ACTUALLY MUCH STRONGER THAN DEPICTED BY THE MODELS YESTERDAY, AS
SFC HIGH PRES MOVES TO THE EASTERN SEABOARD. THIS WILL RESULT IN
MOSTLY SUNNY SKIES ALONG WITH TEMPS MODERATING INTO THE MID/UPPER 40S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AN UPPER LEVEL RIDGE WILL SLOWLY PUSH TO THE EAST SUNDAY AS A SW
TROUGH AND A SFC LOW MOVE FROM THE CENTRAL PLAINS TO THE NORTHEAST,
JUST SOUTH OF THE HUDSON BAY BY SUNDAY AFTERNOON. A COLD FRONT WILL
APPROACH THE CWA SUNDAY EVENING AND BRING A CHANCE OF RAIN TO THE
CWA. THE FRONT LOOKS TO STALL JUST EAST OF THE CWA. THIS SHOULD KEEP
MOST OF THE COLDER AIR TO THE WEST, ALLOWING FOR THE PRECIPITATION
TO BE RAIN. HOWEVER, THERE IS A CHANCE ENOUGH COLD AIR MOVES IN FOR
EITHER A MIX OF A CHANGE OVER TO SNOW, ESPECIALLY IN HIGHER
ELEVATIONS. THE FRONT MOVES VERY LITTLE FOR THE REMAINDER OF THE
EXTENDED FORECAST PERIOD, KEEPING A MENTION OF PRECIPITATION THROUGH
WEDNESDAY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
UPR LVL TROF AND ASSCD 2NDRY SFC TROF CRNTLY WORKING ACRS THE
FCST AREA. AREAS OF MVFR CIGS/VSBY`S WITH -SHRA/-SHSN...MOST
WDSPRD ACRS CNTRL NY...WILL PERSIST INTO THE EVNG HRS. DIFFS IN
THE MDLS W/RESPECT TO THE TIMING OF CLEARING TNGT...WITH CRUDE
EXTRAPOLATION SUPPORTING THE SLOWER RUC SCENARIO. HOWEVER...WE
THINK THE INDICATION OF MVFR CIGS PERSISTING WELL INTO THE OVRNGT
HRS AT PLACES LIKE ITH/BGM/AVP IS OVERDONE BY THE RUC. WE LEANED
TWDS A COMPROMISE WHICH SUGGESTS CLEARING OR PARTIAL CLEARING AT
MOST SPOTS IN THE 03-06Z TIME FRAME. AFTER THIS MSTR LIFTS
OUT..XPCT SCT-BKN HI CLDS ON THU. WINDS THIS AFTN AHEAD OF THE SFC
TROF SWLY 10-20 KTS...BECMG W TO NW 10-20 KTS BEHIND THE TROF.
WINDS SUBSIDING TNGT TO 5-10 KTS...THEN WRLY ON THU ARND 10 KTS.
OUTLOOK...
THURSDAY NIGHT...VFR.
FRIDAY...BRIEF PD OF MVFR PSBL ACRS CNTRL NY DUE TO CDFNT AND SCT
-SHRA.
FRI NGT/SATURDAY/SUNDAY...VFR.
MON...MVFR/IFR AS RAIN DVLPS ACRS THE AREA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM
NEAR TERM...RRM
SHORT TERM...RRM
LONG TERM...SLI
AVIATION...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1247 PM EST WED NOV 30 2011
.SYNOPSIS...
A DISTURBANCE IN THE UPPER ATMOSPHERE WILL BRING SCATTERED SHOWERS
TO THE AREA TODAY. THE BEST SHOT AT PRECIPITATION WILL COME THIS
AFTERNOON. SOME WET SNOW MAY MIX WITH THE RAIN. A FEW SNOW SHOWERS
ARE POSSIBLE EARLY TONIGHT OTHERWISE HIGH PRESSURE WILL BRING A
RETURN TO DRY WEATHER WHICH WILL LAST THROUGH THURSDAY. ANOTHER
WEAK DISTURBANCE WILL BRING THE NEXT CHANCE OF PRECIPITATION
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
12 PM UPDATE...SURFACE TROF NOW ENTERING THE WESTERN PTN OF CWA.
SCATTERED RAIN/SNOW SHOWERS ARE OCCURRING BEHIND BOUNDARY WHICH
AGREES WITH CURRENT FORECAST, NO SIGNIFICANT CHANGES OTHER THAN
MINOR TEMP/POP ADJ.
10 AM UPDATE...SFC LOW CURRENTLY OVER SOUTHERN QUEBEC WITH SFC
TROF BACK ACROSS EXTREME WESTERN NEW YORK. FRONTAL MOISTURE/LIFT
COMBINED WITH COLD CORE ALOFT THIS AFTERNOON WITH MAKE FOR
SCATTERED RAIN SHOWERS THIS AFTERNOON ACROSS CENTRAL NEW YORK.
BOUNDARY LAYER TOO WARM THROUGH MIDDAY FOR SNOW SHOWERS. AFTER 18Z
CAA BEHIND TROF WILL DROP TEMPS ENOUGH FOR A RAIN/SNOW SHOWER MIX
WITH CONDITIONS MORE FAVORABLE BY MID/LATE AFTERNOON. JUST MINOR
TWEAKS OF POPS/TEMPS.
615 AM UPDATE...AREA OF RAIN FROM THIS MORNING HAS ALMOST MOVED
OUT OF THE AREA. KEPT POPS FOR ANOTHER HOUR OR TWO ACROSS THE FAR
NORTH AND EAST...OTHERWISE REMOVED POPS TO EMPHASIZE THE LULL IN
PRECIP. EXPECTED NOW THROUGH MIDDAY. CONTINUED TO SHOW INCREASING
CHANCES FOR RAIN OR SNOW LATER TODAY AS THE COLD CORE ALOFT MOVES
OVERHEAD AND WE GET INTO THE BACKSIDE OF THE UPPER LOW. PREVIOUS
AFD IS BELOW.
4 AM UPDATE...THE COLD FRONT WHICH BROUGHT US STEADY RAIN
LAST NIGHT HAS MOVED TO OUR NORTHEAST. BEHIND THE FRONT WE ARE NOW
BEING IMPACTED BY THE UPPER LEVEL LOW NOW MOVING INTO WESTERN NY.
A GOOD SHOT OF RAIN IS MOVING THROUGH THE CENTRAL PART OF THE CWA
NOW...JUST AHEAD OF THE UPPER LOW. MOST OF THIS PRECIP. THIS
MORNING WILL FALL IN THE FORM OF RAIN. HOWEVER BACK TO THE
WEST...CLOSER TO THE COLDER AIR ALOFT...SOME WET SNOW MAY MIX IN
PRIOR TO DAYBREAK OVER THE WESTERN SOUTHERN TIER. THIS WILL BE
ESPECIALLY TRUE OVER THE HIGHER TERRAIN AS EVIDENT BY WELLSVILLE
NOW REPORTING SOME MIXED PRECIP AT LAST OB. IN FACT OUR RADAR IS
SHOWING A NICE BRIGHT BANDING FEATURE NOW AS THE STEADIER
PRECIPITATION MOVES CLOSE TO THE RADAR (KBGM) WITH FREEZING LEVELS
BEING BETWEEN 2500 AND 4000 FEET.
WE SHOULD SEE A LULL IN THE PRECIPITATION BEYOND EARLY THIS
MORNING WITH ALL MODELS INDICATING THAT AS OUR STEADY AREA OF RAIN
LIFTS NORTHEAST...IT WILL FALL APART AS WE LOSE UPPER LEVEL
SUPPORT. YOU CAN LOOK AT SW NY AND NW PA NOW AS A GOOD PICTURE OF
WHAT MOST OF TODAY WILL LOOK LIKE THROUGH EARLY AFTERNOON.
EVENTUALLY LATER TODAY AS THE UPPER LOW MOVES NORTH...WE WILL
BEGIN TO SEE WRAP AROUND PRECIP MOVE BACK INTO THE AREA. 850 TEMPS
COOL TO BETWEEN -3C AND -6C DURING THIS TIME WHICH SHOULD SUPPORT
A GRADUAL TRANSITION TO WET SNOW. BOUNDARY LAYER TEMPS WILL KEEP
ANY ACCUMS LIMITED TO A COATING ACROSS THE HIGHER TERRAIN.
TONIGHT WRAP AROUND MOISTURE WILL QUICKLY DIMINISH BUT JUST ENOUGH
COOL AIR WILL EXIST FOR A SHORT WINDOW OF LAKE EFFECT SNOW
SHOWERS EARLY THIS EVENING. THE LIMITING FACTORS WILL BE THE SHORT
DURATION OF THE FAVORABLE CONDITIONS (LAKE DELTA T`S NEAR 14 AND A
NORTHWEST FLOW)...AND AN INVERSION UNDER 850 MB. CONTINUED A
SLIGHT CHANCE FOR SNOW SHOWERS ACROSS THE NORTHERN HALF OF THE CWA
EARLY THIS EVENING TO ACCOUNT FOR THIS BEFORE DRYING OUT RAPIDLY.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
4 AM UPDATE...HIGH PRESSURE CONTROLS OUR WEATHER THURSDAY WITH DRY WEATHER
EXPECTED. SKIES SHOULD BE FAIRLY SUNNY BUT A FEW EXTRA CLOUDS WILL
BE POSSIBLE FROM THE FINGER LAKES NORTHWARD AS WAA WILL HELP TO
CREATE SOME MID LEVEL CLOUDS. NEXT SYSTEM ARRIVES IN THE FORM OF A
COLD FRONT FRIDAY. STILL A FAIR AMOUNT OF UNCERTAINTY WITH HOW
MUCH OF AN IMPACT THIS FRONT HAS IN OUR AREA IN TERMS OF
PRECIPITATION. THE NAM SHOWS NO QPF IN OUR AREA AS THE FRONT MOVES
THROUGH...WHILE THE EURO...THE WETTEST OF THE MODELS...STILL SHOWS
LESS THAN A TENTH OF AN INCH. THE GFS IS IN THE MIDDLE. CONTINUED
TO SIDE WITH THE EURO...WHICH HPC GUIDANCE SUPPORTS...AND IS IN
LINE WITH OUR CURRENT FORECAST. THE OTHER DIFFICULT PART OF THE
FORECAST IS PTYPE WITH THE WETTER EURO SOLUTION ALSO BEING THE
COLDER OF THE MODELS. DECIDED TO WORD THE FORECAST RAIN OR SNOW
FRIDAY AND LOW MAX T`S A BIT TO BE IN LINE WITH THE PTYPE
FORECAST. 850S ON THE EURO ARE BETWEEN -3C AND -6C...AND 925S ARE
NEAR 0C OR JUST BELOW...WHICH SHOULD SUPPORT FLAKES ESPECIALLY AS
YOU GET RIGHT OUT OF THE VALLEYS THEMSELVES. WE ARE STILL TALKING
ABOUT A VERY LOW QPF EVENT AND WITH TEMPS ABOVE FREEZING...NOT
EXPECTING MUCH.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
1 AM UPDATE...
LITTLE CHANGE. MODELS STILL CLOSE TO EACH OTHER AND PREVIOUS RUNS.
DRY AND MILD AT THE START WITH A SURFACE HIGH SAT AND SAT NGT,
THEN A SLOW MOVING COLD FRONT AND RAIN CHANGING TO SNOW AS AN
UPPER LEVEL TROF MOVES IN TUESDAY. LINGERING SNOW SHOWERS INTO
WEDNESDAY. CLOSE TO NORMAL TEMPS FOR TUESDAY.
PREVIOUS DISCUSSION...
A WEAK SHORT WAVE TROUGH WILL MOVE ACROSS THE CWA FRIDAY NIGHT. BY
SATURDAY MORNING, A RIDGE OF HIGH PRESSURE WILL BUILD IN,
BRINGING MAINLY QUIET WEATHER TO THE FORECAST AREA. ANOTHER,
STRONGER, SW WILL APPROACH THE CWA LATE SUNDAY AFTERNOON. THIS
WILL BRING ANOTHER ROUND OF PRECIPITATION FROM SUNDAY EVENING
THROUGH TUESDAY. CURRENTLY THINKING THIS SHOULD AGAIN BE MAINLY A
RAIN EVENT. SOME COLD AIR WILL MOVE INTO THE AREA BY TUESDAY
MORNING WHICH SHOULD ALLOW WHATEVER SHOWER ARES TILL AROUND TO
CHANGE OVER TO SNOW.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
UPR LVL TROF AND ASSCD 2NDRY SFC TROF CRNTLY WORKING ACRS THE
FCST AREA. AREAS OF MVFR CIGS/VSBY`S WITH -SHRA/-SHSN...MOST
WDSPRD ACRS CNTRL NY...WILL PERSIST INTO THE EVNG HRS. DIFFS IN
THE MDLS W/RESPECT TO THE TIMING OF CLEARING TNGT...WITH CRUDE
EXTRAPOLATION SUPPORTING THE SLOWER RUC SCENARIO. HOWEVER...WE
THINK THE INDICATION OF MVFR CIGS PERSISTING WELL INTO THE OVRNGT
HRS AT PLACES LIKE ITH/BGM/AVP IS OVERDONE BY THE RUC. WE LEANED
TWDS A COMPROMISE WHICH SUGGESTS CLEARING OR PARTIAL CLEARING AT
MOST SPOTS IN THE 03-06Z TIME FRAME. AFTER THIS MSTR LIFTS
OUT..XPCT SCT-BKN HI CLDS ON THU. WINDS THIS AFTN AHEAD OF THE SFC
TROF SWLY 10-20 KTS...BECMG W TO NW 10-20 KTS BEHIND THE TROF.
WINDS SUBSIDING TNGT TO 5-10 KTS...THEN WRLY ON THU ARND 10 KTS.
OUTLOOK...
THURSDAY NIGHT...VFR.
FRIDAY...BRIEF PD OF MVFR PSBL ACRS CNTRL NY DUE TO CDFNT AND SCT
-SHRA.
FRI NGT/SATURDAY/SUNDAY...VFR.
MON...MVFR/IFR AS RAIN DVLPS ACRS THE AREA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN/RRM
SHORT TERM...HEDEN
LONG TERM...SLI/TAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
257 AM EST WED NOV 30 2011
.SYNOPSIS...
COLD AND DRY HIGH PRESSURE WILL BUILD INTO THE CAROLINAS THROUGH
FRIDAY. A DRY COLD FRONT IS EXPECTED TO PUSH SOUTH OVER THE AREA
EARLY SATURDAY. A WARMING TREND WILL OCCUR LATE IN THE WEEKEND
INTO EARLY NEXT WEEK. A COLD FRONT WILL APPROACH ON TUESDAY
BRINGING THE NEXT CHANCE OF RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...THE ANOMALOUSLY COLD UPPER LOW THAT BROUGHT
SNOW TO PARTS OF THE SOUTHEAST YESTERDAY IS NOW LIFTING RAPIDLY
NORTH INTO THE EASTERN GREAT LAKES. THE COLDEST AIR AT 850 MB
BYPASSED THE EASTERN CAROLINAS WELL TO THE NORTH AND WEST...AND IN
FACT WESTERLY WINDS ARE ALREADY BRINGING IN WARMER AIR AT 850 MB.
HIGH PRESSURE CENTERED OVER THE SOUTHERN PLAINS WILL MOVE TO
TENNESSEE AND MISSISSIPPI THIS EVENING...AND ON INTO WEST VIRGINIA
BY DAYBREAK THURSDAY. THIS WILL ALLOW OUR SURFACE WINDS TO VEER FROM
WESTERLY THIS MORNING TO NORTHERLY LATE TONIGHT.
AN AREA OF STRATUS ACROSS THE NC EASTERN PIEDMONT AND COASTAL PLAIN
IS THE RESULT OF LOW-LEVEL MOISTURE TRAPPED UNDERNEATH A BUILDING
SUBSIDENCE INVERSION ALOFT. THE GFS DOES NOT SEE THIS MOISTURE...
HOWEVER THE NAM AND HRRR DO. BOTH OF THESE MODELS FORECAST THE LOW
CLOUDS TO CONTINUE SLIDING EAST-SOUTHEAST THROUGH DAYBREAK...THEN
BURNING OFF BY 10 AM. SKIES SHOULD BECOME SUNNY THROUGHOUT THE
EASTERN CAROLINAS TODAY WITH HIGHS 55-57. CLEAR SKIES WILL CONTINUE
TONIGHT WITH ONLY A LIGHT NORTHERLY BREEZE EXPECTED. LOWS SHOULD
FALL INTO THE LOWER 30S EXCEPT A FEW DEGREES WARMER NEAR THE COAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL BE BUILDING IN FROM THE
WEST THURSDAY THROUGH FRI AS RIDGE BUILDS IN THROUGH THE MID TO
UPPER LEVELS. EXPECT PLENTY OF SUBSIDENCE WITH A COOL AND DRY AIR
MASS IN PLACE IN A DEEP NORTHERLY FLOW THROUGH MOST OF THE SHORT
TERM PERIOD. GRADIENT WEAKENS LATE THURS INTO FRI PROVIDING BETTER
RADIATIONAL COOLING CONDITIONS THURS NIGHT. OVERNIGHT LOW TEMP
READINGS WILL DROP CLOSE TO FREEZING IN MANY PLACES AS DEWPOINT
TEMPS RUN NEAR 30 OR BELOW. DAY TIME HIGHS WILL HAVE TROUBLE
REACHING 60 ON THURS WITH PLENTY OF LATE FALL SUNSHINE. AS 850
TEMPS REBOUND AND H5 HEIGHTS RISE...TEMPS BEGIN TO WARM INTO THE
60S BY FRI AFTN.
THE HIGH PRESSURE BECOMES DISPLACED TEMPORARILY AS A DRY BACK DOOR
FRONT MOVES DOWN FROM THE NORTH LATE FRI...BUT RIDGE ALOFT WILL
HOLD IT MAINLY NORTH OF AREA. NORTHERLY WINDS MAY BACK BRIEFLY TO
THE W-NW BUT OVERALL COOL AND DRY WEATHER WILL CONTINUE ON INTO
THE WEEKEND. PCP WATER VALUES WILL BE DOWN NEAR A QUARTER OF AN
INCH THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...STRONG HIGH PRESSURE WILL CONTINUE TO RIDGE
DOWN THE EAST COAST FROM NEW ENGLAND. AS THE CENTER SHIFTS OFF
SHORE LATE SAT THE WINDS WILL BEGIN TO SHIFT BECOMING MORE ON
SHORE THROUGH SUNDAY AS THE HIGH PROGRESSES FARTHER EAST. RIDGE
HOLDS ON IN THE MID TO UPPER LEVELS WITH HEIGHTS INCREASING
THROUGH SAT AND REMAINING FAIRLY STABLE THROUGH EARLY MONDAY. BY
SUNDAY MOISTURE WILL BEGIN TO RETURN TO THE FORECAST AREA AS
RETURN FLOW SETS UP ALOFT. PCP WATER VALUES BEGIN TO CREEP BACK UP
TOWARD A HALF TO THREE QUARTERS OF AN INCH. SURFACE FLOW WILL BE A
LITTLE SLOWER TO COME AROUND TO A MORE SOUTHERLY DIRECTION AS HIGH
PRESSURE CONTINUES TO RIDGE DOWN FROM THE NORTHEAST. MAY SEE SOME
CLOUDS BACK IN THE FORECAST BY SUNDAY.
BY MONDAY AN INCREASINGLY DEEPER WARMER AND MOISTER RETURN FLOW
SETS UP. THE GRADIENT TIGHTENS AND LOW LEVEL FLOW SHOOTS UP TO 30
TO 40 KTS. THIS WILL PRODUCE A SURGE IN BOTH WARMTH AND MOISTURE
MON INTO TUES WITH TEMPS BACK UP WELL ABOVE NORMAL. EXPECT READINGS
AROUND 70 MON AND TUES. AS MOISTURE INCREASES AND PCP WATER VALUES
INCREASE UP NEAR AN INCH MON INTO TUES...THERE WILL BE AN
INCREASING CHC OF PCP IN THE FORECAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT VFR THROUGH PERIOD AS HIGH PRESSURE BUILDS INTO
THE REGION. ONE OR TWO SHREDS OF STRATOCUMULUS MAY LINGER
OVERNIGHT...CERTAINLY BECOMING SKC BY DAYBREAK. GUSTS HAVE MOSTLY
SUBSIDED...BUT CANNOT RULE OUT ADDITIONAL BRIEF GUSTS AOB 20KTS. BY
THIS AFTERNOON WINDS WILL BECOME NORTH-NORTHWEST AND CONTINUE
THROUGH TONIGHT...SUBSIDING TO 5 KTS OR LESS BY THIS EVENING.
EXTENDED OUTLOOK...EXPECT VFR THROUGH PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...WESTERLY WINDS WHIPPING ACROSS THE COASTAL
WATERS EARLY THIS MORNING ARE THE RESULT OF HIGH PRESSURE OVER THE
SOUTHERN PLAINS BUILDING EASTWARD. MODELS ARE IN EXCELLENT AGREEMENT
THAT THE TIGHTEST PORTION OF THE PRESSURE GRADIENT (AND HENCE THE
STRONGEST WINDS) SHOULD ABATE WITHIN THE NEXT 3-4 HOURS...WITH
IMPROVING CONDITIONS THIS MORNING INTO THIS AFTERNOON. AS OFTEN
OCCURS DURING THESE SITUATIONS A NOCTURNAL SURGE OF COLD AIR WILL
PUSH OUT ACROSS THE WATERS THIS EVENING...WITH WIND SPEEDS
INCREASING TO 15-20 KT AWAY FROM SHORE. SEAS AT THE FRYING PAN
SHOALS BUOY ARE 7 FT THIS MORNING WITH 4 FOOT SEAS STILL REPORTED AT
THE NEARSHORE WRIGHTSVILLE BEACH CORMP BUOY. GIVEN THE WESTERLY
FETCH NEARSHORE SEAS SHOULD DIMINISH RATHER QUICKLY THIS
MORNING...BUT IT MAY TAKE SOME MORE TIME TO SEE IMPROVEMENT SOUTH
AND EAST OF BALD HEAD ISLAND WHERE A MORE-SIGNIFICANT EFFECTIVE
FETCH EXISTS. WE WILL EXTEND THE SMALL CRAFT ADVISORY ANOTHER FEW
HOURS FOR THE NC WATERS...BUT ALLOW IT END ON SCHEDULE FOR THE SC
WATERS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...NORTHERLY WINDS WILL CONTINUE THROUGH MUCH
OF THE PERIOD AS HIGH PRESSURE BUILDS IN FROM THE WEST. GRADIENT
WILL RELAX AS CENTER OF HIGH SHIFTS CLOSER OVERHEAD LATE THURS
INTO FRI AND MAY SEE A LITTLE SURGE OVERNIGHT FRI AS BACK DOOR
FRONT PUSHES SOUTH AND HIGH PRESSURE REASSERTS ITSELF. WINDS
SPEEDS ARE EXPECTED TO DIMINISH TO 15 KNOTS OR LESS THURSDAY
NIGHT INTO FRI WITH SEAS 4FT OR LESS.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL RIDGE DOWN INTO THE
CAROLINAS FROM CENTER UP IN NEW ENGLAND. THIS AREA WILL GET
STRETCHED AS CENTER SHIFTS OFF THE NEW ENGLAND COAST AND MOVES
FURTHER OFF SHORE THROUGH SUNDAY. NORTHERLY WINDS UP CLOSER TO 15
KTS ON SAT WILL DIMINISH AND VEER AROUND THROUGH SUNDAY BECOMING
MORE ON SHORE BUT REMAINING LESS THAN 15 KTS THROUGH EARLY NEXT
WEEK. SEAS WILL BASICALLY BE 2 TO 4 FT WITH A SLIGHTLY LONGER
PERIOD SOUTHEAST SWELL MIXING IN THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/SGL
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1000 PM CST THU DEC 1 2011
.UPDATE...
FRONTOGENETICALLY FORCED SNOW BAND IS SKIMMING FAR SOUTHERN
WISCONSIN AND NORTHERN ILLINOIS...AS THE RUC HAS BEEN INDICATING.
LOCATIONS SOUTHEAST OF A MILWAUKEE TO MONROE LINE WILL HAVE THE
BEST CHANCE TO SEE THE LIGHT SNOW. PULLED THE POPS FARTHER SOUTH
AND TIGHTENED THE AREA LIKELY TO SEE THE SNOW. UP TO 1/2 INCH
POSSIBLE NEAR THE ILLINOIS BORDER...ESPECIALLY IN SOUTHERN
WALWORTH AND KENOSHA COUNTIES...WITH A RAPID TAPERING TO THE
NORTH. PATCHY DRIZZLE AT LOCATIONS WHERE THE -10 TO -20C DENDRITE
GROWTH ZONE HAS NOT YET SATURATED OUTSIDE OF THE MAIN SNOW BANDS.
TEMPERATURES WILL FALL AS SKIES CLEAR FROM NORTHWEST TO SOUTHEAST
BEHIND THE 500 MB TROUGH...WITH A CURRENT TIMING BRINGING THE
CLEARING TO THE SOUTHEASTERN-MOST COUNTIES BETWEEN 3 AM AND 4 AM
AS THE RIDGE OF SURFACE HIGH PRESSURE MOVES OVER THE REGION.
CURRENT TREND LOOKS ON TRACK.
&&
.AVIATION/06Z TAFS/...
WILL TAKE ANY LINGERING MVFR VSBYS/CIGS WITH THE LIGHT SNOW OUT
OF KMKE BY 06Z AND KENW BY 07Z...WITH CLEARING EXPECTED ABOUT 2
HOURS AFTERWARD. RIDGE OF HIGH PRESSURE BRINGS VFR CONDITIONS
THROUGH REMAINDER OF TAF PERIOD...WITH PRECIPITATION FROM NEXT
SYSTEM NOT MOVING INTO SOUTHERN WISCONSIN UNTIL AFTER 06Z SATURDAY.
WILL BRING A VCNTY INTO MKE PRIOR TO 12Z...BUT LEAVE CIGS/VSBYS AT
VFR LEVELS FOR NOW UNTIL A MORE THOROUGH LOOK AT LATEST MODEL RUNS
PRODUCE EXPECTED BETTER TIMING ON PRECIPITATION ONSET.
&&
.PREV DISCUSSION... /ISSUED 334 PM CST THU DEC 1 2011/
SHORT TERM...
TONIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
BAND OF POST FRONTAL LIGHT PRECIP CURRENTLY DROPPING SOUTHEAST
THROUGH THE FORECAST AREA. BEST COMBINATION OF
FRONTOGENESIS...Q-VECTOR CONVERGENCE...AND MOISTURE IS ACROSS THE
SOUTHEAST THIS EVENING. THUS BUMPED POPS UP HERE WITH ALL MODELS
SPITTING OUT A FEW HUNDREDTHS OF LIQUID. BACK EDGE OF PRECIP ALREADY
MOVING INTO THE FORECAST AREA...SO MAY NEED TO SPEED UP THE END OF
THE PRECIP THIS EVENING...AT LEAST FOR AREAS NORTHWEST OF MADISON.
STILL EXPECTING MAINLY SNOW...BUT LIGHT PRECIP STRUGGLING TO COOL
THINGS ENOUGH FOR SNOW INITIALLY...SO ADDED CHANCE FOR RAIN AS THE
PRECIP ARRIVES IN THE SOUTHEAST THIS EVENING. STILL EXPECTING SNOW
AMOUNTS TO BE ONE HALF INCH OR LESS.
SKIES SHOULD CLEAR BY MORNING AS HIGH PRESSURE APPROACHES...WITH
SUNNY SKIES FRIDAY UNDER THE HIGH. LOWS TONIGHT WILL BE SLOW TO
FALL...BUT THEN WILL PROBABLY QUICKLY DROP AS SKIES CLEAR AND WINDS
BECOME LIGHTER. COULD SEE UPPER TEENS FROM MADISON WESTWARD. NEAR
NORMAL TEMPS INTO THE MID 30S THEN EXPECTED FRIDAY.
FRIDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM
SLY WINDS AND WARM ADVECTION EXPECTED FRI NT INTO SAT AHEAD OF AN
APPROACHING LONG WAVE UPPER TROUGH THAT EXTENDS FROM CENTRAL
CANADA SWWD TO THE 4 CORNERS REGION. THE SRN PORTION OF THE UPPER
TROUGH OVER THE 4 CORNERS WILL EJECT NEWD AND REACH THE WRN HALF
OF WI BY 12 SUN. THE SHORTWAVE TROUGH WILL GET SHEARED OUT WITH
TIME BUT A 1007 MB SFC LOW WILL TRACK FROM ERN KS ON SAT TO NEAR
OR JUST SOUTH OF GREEN BAY BY 12Z SUN. THIS TRACK IS A GOOD
CONSENSUS OF THE ECMWF...NAM...AND UKMET AND WILL FOLLOW THIS
TRACK FOR FORECAST GUIDANCE. THE GFS IS CURRENTLY AN OUTLIER WITH
THE LOW GOING OVER CHICAGO WITH THE RELATED COOLER AND MORE SNOWY
RESULTS FOR SRN WI.
THE SLY LOW LEVEL JET AND WARM/MOIST ADVECTION WILL BRING
RAIN/SNOW INTO MOST OF THE CWA FOR LATE FRI NT WITH THE MIXTURE
MAINLY IN THE NRN CWA. THE SLY WINDS WILL CONTINUE TO WARM TEMPS
INTO SAT SO ALL RAIN EXPECTED. RAIN WILL THEN TRANSITION TO RAIN
AND SNOW SAT NT BUT CONFIDENCE PCPN TYPE WILL REMAIN ALL RAIN OVER
SE WI. DO EXPECT SOME CHANGEOVER TO ALL SNOW OVER THE NW CWA WITH
SNOW ACCUMULATIONS OF 1-2 INCHES. PCPN TO LINGER THROUGH SUN AM
BEFORE COLD AND DRY ADVECTION TAKES OVER.
LONG TERM...
MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE LOW TO MEDIUM
A DRY COLD FRONT WILL FOLLOW IN THE WAKE OF THE DEPARTING LOW FOR
MONDAY AFTERNOON OR NIGHT. A RIDGE OF HIGH PRESSURE WILL THEN
PREVAIL FOR TUE. A LARGE POLAR TROUGH WILL RESIDE OVER CANADA FOR
THE WEEK BUT A PORTION OF IT MAY DIG INTO THE NW USA...THUS HEIGHT
RISES AND SFC WINDS BECOMING SWLY FOR WED AND THU. SO DRY WX WITH
BELOW NORMAL TEMPS TO START THE NEW WEEK WITH TEMPS WARMING TO
MORE SEASONAL LEVELS LATER IN THE WEEK.
AVIATION/00Z TAFS/...FORECAST STILL LOOKS ON TRACK FOR LIGHT SNOW
LATE AFTERNOON AND EVENING ACROSS SOUTHERN WISCONSIN. MAY MIX WITH
RAIN FOR A WHILE AS THE PRECIP MOVES IN...BUT THEN CHANGE TO ALL
SNOW. VFR CONDITIONS EXPECTED UNTIL THE SNOW ARRIVES. ACCUMULATIONS
STILL LOOK LIGHT...GENERALLY ONE HALF OF AN INCH OR LESS. VFR
CONDITIONS LIKELY TO RETURN LATE IN THE NIGHT AS HIGH PRESSURE
APPROACHES.
NORTHERLY WINDS WILL BECOME LIGHTER INTO THE NIGHT AS THE HIGH DRAWS
NEAR...TURNING SOUTHERLY ON THE WEST SIDE OF THE HIGH LATE FRIDAY
MORNING OR EARLY AFTERNOON.
MARINE...NORTHERLY WINDS WILL BUILD WAVES TO AROUND 4 FEET TOWARD
THE OPEN WATERS TONIGHT...ESPECIALLY SOUTH OF NORTH POINT LIGHT.
SEEMS TOO MARGINAL FOR A SMALL CRAFT ADVISORY THOUGH. BETTER CHANCE
FOR SMALL CRAFT CONDITIONS EXPECTED LATE FRIDAY NIGHT INTO
SATURDAY...AS SOUTHERLY WINDS AHEAD OF APPROACHING LOW PRESSURE
BUILDS HIGHER WAVES.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...REM
TONIGHT/FRIDAY AND AVIATION/MARINE...DDV
FRIDAY NIGHT THROUGH THURSDAY...GEHRING
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1220 AM EST FRI DEC 2 2011
.SYNOPSIS...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC REGION FROM THE WEST
TONIGHT THROUGH WEEKEND. A WEAK...DRY COLD FRONT WILL CROSS INTO
THE AREA FRIDAY NIGHT...BRINGING SLIGHTLY COOLER TEMPERATURES
SATURDAY. MILDER CONDITIONS RETURN FOR THE LATTER HALF OF THE
WEEKEND INTO EARLY NEXT WEEK AHEAD OF A SLOW MOVING COLD
FRONT...WHICH APPROACHES THE REGION FROM THE WEST BY THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
LATEST WX ANALYSIS DEPICTS ~1028MB SURFACE HIGH PRESSURE OVER
E KY/TN. ALOFT...TROUGH-RIDGE-TROUGH PATTERN EVIDENT ON RUC H5
ANALYSIS AS MID LEVEL TROUGHING HAS NOW TRANSITIONED OFF THE EAST
COAST...WITH LOW AMPLITUDE H5 RIDGING TO THE WEST OVER THE GULF
COAST/LOWER MS VALLEY...WITH CLOSED OFF/POSITIVELY TILTED UPPER
LEVEL LOW PRESSURE REMAINS IN PLACE OVER BAJA/SOUTHERN
CALIFORNIA.
BREEZY CONDITIONS STILL IN PLACE OVER MAINLY COASTAL ZONES THIS
AFTERNOON AS A RESULT OF PRESSURE GRADIENT BETWEEN DEPARTING MID
LEVEL TROUGH...AND HIGH PRESSURE TO THE WEST. COASTAL AREAS
SHOULD CONTINUE TO BE BREEZY (GUSTS TO 15-17 KT) FOR A FEW MORE
HOURS BEFORE DECOUPLING/RELAXING PRESSURE GRADIENT ALLOWS FOR
WINDS TO DROP OFF EARLY THIS EVENING. OTHERWISE...A MOSTLY CLEAR
AND PLEASANT LATE FALL AFTERNOON ACROSS THE CWA...MAXIMA WL AVERAGE
OUT INTO THE MID 50S INLAND...LOW TO MID 50S OVER COASTAL ZONES.
CLEAR SKIES/LIGHT WINDS PORTEND TO GOOD RADIATING CONDITIONS
TONIGHT. LOOKING FOR TEMPERATURES BE CLOSE TO/JUST BELOW LAST
NIGHTS/THIS MORNING`S LOWS. LOOK FOR LOWS INTO THE M-U 20S
INLAND...LOW TO MID 30S OVER COASTAL ZONES.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
LATE WEEK/WEEKEND TIME FRAME CHARACTERIZED BY SLOWLY BUILDING UPPER
LEVEL RIDGING WITH TIME OVER THE EASTERN CONUS...RESULTING IN
CONTINUED DRY WEATHER THROUGH THE PERIOD.
FRIDAY...
HIGH PRESSURE BECOMES ENTRENCHED OVER THE MID ATLANTIC
STATES THROUGH THE WEEKEND. AS A CUTOFF LOW DEVELOPS OVER THE
SOUTHWESTERN US...A WEAK UPPER LEVEL TROUGH WILL BECOME SEPARATED
FROM IT AND DRIFT ACROSS THE NORTHERN PLAINS/UPPER GREAT
LAKES...BEFORE SLOWLY PUSHING ACROSS NEW ENGLAND BY FRIDAY NIGHT.
THIS FEATURE WILL EVENTUALLY PUSH WEAK/DRY FRONTAL BOUNDARY TO OUR
NORTH THROUGH THE REGION LATE TOMORROW INTO SATURDAY WITH LITTLE
MORE THAN A FEW MID-HIGH CLOUDS PUSHING ACROSS THE AREA. MAXIMA
SLIGHTLY WARMER THAN TODAY`S VALUES...GENERALLY INTO THE M/U 50S
AREA WIDE...NEAR 60 WELL INLAND. SO WHILE WE CAN EXPECT A SLIGHTLY
MILDER EVENING FRIDAY NIGHT...HAVE SIDED CLOSER TO COOLER ENVELOPE
OF MAV GUIDANCE IN EXPECTATION OF LIGHT WINDS OVER LAND AND STILL
RELATIVELY SCANT MID LEVEL CLOUD COVER AS HIGH PRESSURE SLIDES
OVERHEAD. EARLY MORNING LOWS FRI NIGHT/SAT MORNING GENERALLY INTO
THE L-M30S TO NEAR 40 ALONG COASTAL ZONES.
SATURDAY...
THE SURFACE HIGH BECOMES POSITIVELY TILTED ON SATURDAY AS THE
RIDGE AXIS BEGINS TO SHIFT OFFSHORE. DESPITE AFOREMENTIONED
WARMING WITH TIME ALOFT AS SUBTROPICAL RIDGE BEGINS TO BUILD ACROSS
THE SOUTHEASTERN CONUS...TEMPERATURES WILL BE MODESTLY COOLER
SATURDAY DUE TO THE INFLUENCE OF MODIFYING ~1036MB SFC HIGH
PRESSURE PUSHING IN FROM THE WEST. AS WE`VE SEEN SEVERAL TIMES
ALREADY THIS FALL...LIMITED MIXING NOTED ON FORECAST SOUNDINGS FOR
SATURDAY (GENERALLY TO ~950-925MB) WILL KEEP TEMPERATURES A BIT
LOWER THAN LOCAL THICKNESS TOOLS AND WARMER MAV GUIDANCE DEPICT.
AS SUCH...HAVE GONE CLOSER TO COOLER MET VALUES FOR MAXIMA ON
SATURDAY WHICH YIELD SEASONABLE...ALBEIT SLIGHTLY COOLER...MAXIMA
INTO THE LOW TO MID 50S.
SATURDAY NIGHT/SUNDAY...
SURFACE HIGH PIVOTS TO THE MID-ATLANTIC/SE COAST AND THEN
OFFSHORE SAT NIGHT THROUGH SUNDAY...WITH DEVELOPING RETURN (SOUTH-
SOUTHEAST) FLOW AND CONTINUED BUILDING OF RIDGING ALOFT INITIATING
MODERATING TEMPERATURE TREND FOR SATURDAY NIGHT THROUGH THE EARLY
PORTION OF NEXT WEEK. LOOK FOR EARLY MORNING LOWS CONTINUED DRY
AND MILDER CONDITIONS SUNDAY WITH MAXIMA INTO THE L-M 60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
OVERALL PATTERN IN THE EXTENDED FAVORS A DOMINANT MID/UPPER LEVEL
RIDGE CENTERED FROM THE GULF OF MEXICO ENE ACRS FLORIDA AND TOWARDS
BERMUDA. MEANWHILE...A DEEP TROUGH OVER CENTRAL CANADA WILL
GRADUALLY PUSH SOUTH AND TAKE ON A POSITIVE TILT (OR EVEN BECOME
CUTOFF) OVER THE CENTRAL CONUS. THIS SETUP WILL BE VERY SLOW TO
CHANGE THROUGH THE MIDDLE OF NEXT WEEK...AND WILL KEEP BULK OF
PRECIPITATION OFF TO OUR WEST UNTIL WED. FOR THE MID ATLC AND SE
STATES...THIS WILL ALSO TRANSLATE INTO WELL ABOVE AVG TEMPERATURES
MON-TUE...AND POSSIBLY WED BEFORE COOLING DOWN TO AROUND AVG ON THU.
GIVEN THE CONTINUED MODEL DISCREPANCIES (LATEST ECMWF REMAINING
ABOUT 12-18 HRS SLOWER THAN THE GFS/GLOBAL GEM
ENSEMBLES....CONFIDENCE IN TUE-THU FCST IS LOWER THAN AVG.
AS WITH PREVIOUS FCST...HAVE GENLY BROAD-BRUSHED A LOW CHANCE POP
ACRS THE NW ZONES...TO DRY OR SLIGHT CHANCE ELSEWHERE FROM LATE MON
THROUGH TUE. WILL FOCUS HIGHEST POPS DURING THE DAY WED/WED EVENING
AS A BLEND OF MODEL TIMING PUSHES THE SFC COLD FRONT THROUGH.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR UFN AS HIGH PRES KEEPS SKIES CLEAR THRU FCST PERIOD. A DRY
FRONTAL BOUNDARY CROSSES THE AREA TONITE SHIFTING WINDS INTO THE
N-NE. VFR CONDITIONS CONT THRU THE WEEKEND.
&&
.MARINE...
NO FLAGS NEXT 12-18 HRS AS HIGH PRS BUILDS OVR THE WATERS KEEPING
CNDTNS BELOW SCA LVLS.
PVS DSCN:
ANOTHER BOUNDARY/COOL SURGE FRI NIGHT...WITH MARGINAL SCA EVENT
LIKELY ONCE AGAIN OVER THE BAY....AND POSSIBLE ON THE COASTAL
WATERS. AS THIS IS LATER 3RD PERIOD...HAVE DECIDED TO WAIT UNTIL
CURRENT HEADLINES END BEFORE RAISING ANOTHER SET (ALTHOUGH FCST
DOES INCLUDE SCA CONDITIONS). THIS SURGE IS FAIRLY BRIEF...AND
SHOULD END BY LATE SAT MORNING ASIDE FROM LINGERING 5 FT SEAS OVER
SOUTHERN COASTAL WATERS. OTHERWISE...BENIGN SAT EVENING THROUGH
MON AS HIGH PRESSURE SETTLES OVER THE REGION AHEAD OF THE NEXT
COLD FRONT. WINDS GRADUALLY TURN SOUTHERLY SUN-TUE BUT WIND SPEEDS
LOOK TO AVG 10-15 KT OR LESS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MAM
NEAR TERM...BKH/MAM
SHORT TERM...MAM/BMD
LONG TERM...LKB
AVIATION...MPR
MARINE...MPR/LKB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
440 AM EST FRI DEC 2 2011
.DISCUSSION...
A COLD MORNING WHERE IT HAS CLEARED OUT OVERNIGHT WITH MANY INTERIOR
SPOTS SEEING TEMPS IN THE SINGLE DIGITS UNDER HIGH PRESSURE AND LOW
PRECIPITABLE WATER VALUES OF AROUND 0.1 INCH. WOULD NOT BE SURPRISED
IF WE SEE A FEW TEMPS NEAR 0F NEAR THE WISCONSIN BORDER WITH DWPTS
JUST ABOVE 0 AT THIS TIME.
LAKE EFFECT CLOUDS ARE STARTING TO RETREAT TO THE NORTH AND EAST AS
HIGH PRESSURE RIDGING ACROSS THE UPPER MS VLY BUILDS ACROSS THE
AREA. EXPECT ANY REMAINING CLOUDS AND FLURRIES TO CLEAR OUT THIS MORNING
YIELDING A MOSTLY SUNNY DAY ACROSS THE AREA. UPPER HEIGHTS BUILD
RATHER QUICKLY TODAY WITH RATHER ABRUPT WARM ADVECTION DEVELOPING
THIS AFTERNOON AS THE WESTERN TROUGH SHIFTS EAST. IN FACT...BY 00Z
THIS EVENING 850MB TEMPS RISE TO -2C ACROSS THE WEST /FROM -12C THIS
MORNING/. SHOULD SEE A NICE RECOVERY IN TEMPS TODAY WITH ALL AREAS
WELL INTO THE UPPER 20S. DEVELOPING DOWNSLOPE S-SW FLOW THIS AFTN MAY
HELP TEMPS NEAR THE LAKESHORE TOP OUT IN THE LOWER 30S.
THE FORECAST BEGINS TO BECOME TRICKY STARTING LATER TONIGHT AND
CONTINUES TRICKY RIGHT THROUGH SUNDAY. STRONG SHORT WAVE ENERGY
CURRENTLY OVER BRITISH COLUMBIA WILL DIVE SOUTHEASTWARD TODAY. THIS
WILL CAUSE AN ALBERTA CLIPPER LIKE SYSTEM TO MOVE ACROSS THE UPPER
LAKES SATURDAY. A PIECE OF ENERGY WILL ALSO BREAK OFF FROM THIS
WAVE...DIVING DUE SOUTH DOWN THE INTERMOUNTAIN WEST HELPING TO EJECT
THE DEEP UPPER LOW OVER THE SOUTHWESTERN STATES TONIGHT INTO
SATURDAY. AS THE FRONT ASSOCIATED WITH THE NORTHERN LOW MOVES ACROSS
THE UPPER GREAT LAKES...GULF MOISTURE WILL STREAM NORTHWARD ALONG
THE FRONT ON SATURDAY. ALTHOUGH SYNOPTIC FORCING NOT BE TERRIBLY
STRONG...THERE WEAK ISENTROPIC LIFT DURING THE DAY ON SATURDAY
SHOULD ALLOW FOR LIGHT PRECIPITATION TO FALL ALONG AND EAST OF THE
FRONT. WITH THIS BEING SAID...HAVE OPTED TO MAINTAIN LIKELY POPS
DURING THE DAY ACROSS THE EASTERN HALF OF THE FORECAST AREA...WITH A
MINIMAL CHANCE FOR PRECIPITATION ACROSS WESTERN UPPER MICHIGAN WHERE
DRIER AIR AND MINIMAL ISENTROPIC LIFT WILL MINIMIZE ANY PCPN
CHANCES. AS FOR PRECIPITATION TYPE ON SATURDAY...EXPECT MOSTLY SNOW
TO FALL EXCEPT FOR AREAS CLOSE TO LAKE MICHIGAN WHERE BOUNDARY TEMPS
WITH SOUTHERLY FLOW SHOULD RISE ENOUGH TO KEEP IT ALL RAIN OR A
RAIN/SNOW MIX. WITH LACK OF SIGNIFICANT UPWARD MOTION...DO NOT
EXPECT ACCUMULATIONS TO AMOUNT TO MORE THAN AN INCH OR TWO WHERE IT
DOES SNOW THE LONGEST.
ALTHOUGH MODELS HAVE COME INTO BETTER AGREEMENT IN BRINGING A
SURFACE LOW ACROSS THE UPPER LAKES SATURDAY NIGHT INTO
SUNDAY...THERE ARE STILL SUBTLE DETAILS WHICH WILL MAKE THE SNOWFALL
FORECAST CHALLENGING. OVERALL...THE LOW TRACK IS BECOMING BETTER
DEFINED WITH A TRACK ACROSS LAKE MICHIGAN AND TO FAR EASTERN UPPER
MI BY SUN MORNING. IN ADDITION...WITH THE EXCEPTION OF THE GFS...THE
MODELS HAVE ALSO COME INTO BETTER AGREEMENT IN SHOWING A SWATH OF
MODERATE PRECIPITATION IN THE FORM OF SNOW TO MOVE ACROSS CENTRAL
UPPER MICHIGAN SAT NIGHT INTO SUNDAY MORNING DURING THE PERIOD OF
BEST FRONTOGENETIC FORCING COMBINED WITH REDUCED STABILITY ALOFT.
WITH THE EXCEPTION OF THE GFS...THE OTHER MODELS ARE IN FAIRLY GOOD
AGREEMENT IN SHOWING A SWATH OF .75 INCH OF PRECIPITATION SAT NIGHT
INTO SUNDAY MORNING. THIS MAKES SENSE GIVEN THE TRACK OF THE SFC AND
850MB LOW COMBINED WITH PRECIPITABLE WATER VALUES AROUND 0.5 INCH.
WITH THAT BEING SAID...HAVE RAISED POPS TO CATEGORICAL FOR THE
EASTERN PART OF THE FORECAST AREA SAT NIGHT INTO SUNDAY AND HAVE
GONE WITH STORM TOTAL SNOWFALL SAT NIGHT INTO SUNDAY OF 5-8 INCHES
MAINLY EAST OF A LANSE TO IRON RIVER LINE. DEPENDING ON THE EXACT
TRACK...MAY SEE SOME PRECIPITATION TYPE CONCERNS ACROSS EASTERN
UPPER AS WELL AS NEAR LAKE MICHIGAN...BUT ONLY IF THE NAM FORECAST
TRACK VERIFIES. ORIGINALLY WAS THINKING ABOUT GOING WITH A WINTER
STORM WATCH FOR PARTS OF CENTRAL UPPER MICHIGAN...BUT OPTED TO HOLD
OFF GIVEN THAT THE HEAVIEST SNOW WILL OCCUR AT NIGHT AND THE FACT
THAT THE STORM WILL MOVE THROUGH RATHER QUICKLY. STILL...FORECAST
AMOUNTS ARE VERY CLOSE TO WARNING CRITERIA AND GIVEN THAT THE SNOW
WILL BE WET IN NATURE /GENERALLY A 12-15:1 RATIO/...A WINTER STORM
WATCH MAY NEED TO BE ISSUED THIS AFTERNOON.
LES EXPECTED SUNDAY NIGHT...HOWEVER THE INTENSITY AND PLACEMENT WILL
DEPEND ON WHETHER ANOTHER WEAK LOW MOVES INTO THE AREA IN THE NW
FLOW AS THE GEM AND GFS SUGGEST. FOR NOW...HAVE OPTED TO GO WITH CHC
POPS NEAR THE LAKESHORE WITH THE HIGHEST POPS WEST.
FOR THE EXTENDED /MONDAY THROUGH THURSDAY/...
WITH SFC HIGH PRESSURE PUSHING IN FROM THE W AND A SFC TROUGH
EXTENDING FROM THE E OVER LAKE SUPERIOR...LOW LEVEL WINDS WILL
GENERALLY BE NW. AN UPPER TROUGH AXIS FROM FAR NERN CANADA TO THE
FAR SWRN CONUS WILL MOVE OVER THE CWA LATE MONDAY INTO TUESDAY. COOL
850MB TEMPS AOB -10C WILL EXIST UNDER THE TROUGH. THIS WILL RESULT
IN LAKE EFFECT SNOW IN NW WIND SNOWBELTS. THE BEST CHANCES FOR SNOW
WILL BE MONDAY...SINCE HIGH PRESSURE AND DRIER AIR WILL MOVE IN FROM
THE W MONDAY NIGHT.
THE SFC HIGH PRESSURE RIDGE WILL THEN PUSH EAST OF THE CWA LATE
TUESDAY...LEADING TO SW WINDS AHEAD OF A TROUGH OVER THE NRN PLAINS.
WITH THE SW WINDS AND 850MB TEMPS AOA -8C WED NIGHT...NO LAKE EFFECT
PRECIP IS EXPECTED.
WED WILL SEE BIG PATTERN CHANGES AS THE SFC TROUGH AND STRONG COLD
FRONT PASS THROUGH THE CWA. THE COOLEST AIR OF THE SEASON IS
INDICATED BY MODELS TO MOVE OVER THE AREA AS A DEEP LOW MOVE S TO
HUDSON BAY. THIS WILL BRING A DEEP...BROAD TROUGH ACROSS MOST OF THE
NRN CONUS WED AND THU. BEHIND THE SFC TROUGH...LOW LEVEL WINDS WILL
BE FROM THE NW AS 850MB TEMPS FALL TO AROUND -20C BY 06Z THU...AND
LOW LEVEL RH PLENTY SUFFICIENT FOR LAKE EFFECT PRECIP.
&&
.AVIATION /FOR 06Z TAF ISSUANCE/
WITH 900 MB TEMPS NEAR -11C...THERE IS CURRENTLY ENOUGH INSTABILITY
TO SUSTAIN LAKE CLOUDS. RUC 925-900 MB RH FCST AND RECENT TRENDS
SUGGEST THAT CLEARING WILL BE SLOW TO ADVANCE THIS EVENING...KEEPING
KIWD/KCMX NEAR THE EDGE OF THE CLOUD AREA. VFR CONDITIONS SHOULD
THEN PREVAIL THE REST OF THE NIGHT INTO FRI.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
A HIGH PRESSURE RIDGE OVER LAKE SUPERIOR WILL KEEP CONDITIONS ON THE
LAKE QUIET OVERNIGHT...WITH FLOW BEING GENERALLY NORTHWEST. THE
RIDGE WILL MOVE OUT BY THIS AFTERNOON. A LOW PRESSURE SYSTEM
CENTERED OVER MANITOBA WILL MOVE TO HUDSON BAY BY
SATURDAY...DRAGGING A TROUGH AND COLD FRONT ACROSS LAKE SUPERIOR
LATE SATURDAY. BETWEEN THE TWO SYSTEMS...THE PRESSURE GRADIENT WILL
STRENGTHEN. AS A RESULT...GALES TO 35-40 KNOTS ARE EXPECTED ON THE
LAKE FROM FRIDAY THROUGH SATURDAY MORNING. WESTERN LAKE SUPERIOR
WILL SEE THE START OF THE GALES FRIDAY AFTERNOON...AND ON FRIDAY
NIGHT THE EASTERN ZONES. ALL OF THE GALE FORCE WINDS SHOULD END
SATURDAY MORNING. WINDS WILL CONTINUE TO GUST TO AROUND 30 KNOTS
SATURDAY AFTERNOON...BEFORE DECREASING TO LESS THAN 25 KNOTS FOR THE
REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ266-267.
GALE WARNING FROM 10 AM EST /9 AM CST/ THIS MORNING TO 7 AM EST
/6 AM CST/ SATURDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
DISCUSSION...MRD
EXTENDED...TITUS
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1239 AM EST FRI DEC 2 2011
UPDATED AVIATION DISCUSSION FOR 06Z TAFS
.SHORT TERM...
FOR TONIGHT...LOW PRESSURE TROUGH RESPONSIBLE FOR LAST NIGHT AND
TODAYS SNOWFALL WILL MAKE ITS WAY FROM EASTERN UPPER MICHIGAN TO
QUEBEC OVERNIGHT. MEANWHILE...A RIDGE EXTENDING FROM HIGH PRESSURE
IN THE CENTRAL PLAINS WILL SETTLE IN OVER UPPER MICHIGAN...BRINGING
QUIETER CONDITIONS TO A MAJORITY OF THE CWA. MAIN CONCERN IS WHETHER
OR NOT LES WILL CONTINUE TO IMPACT EASTERN UPPER MICHIGAN THROUGH
THE NIGHT WITH THE INCOMING DRY AIR. AS OF 15Z...CONDITIONS ACROSS
MINNESOTA WERE DRYING OUT...WITH CLEAR SKIES AND LARGE DEWPOINT
DEPRESSIONS OBSERVED. 12Z SOUNDINGS AT INTERNATIONAL FALLS MN AND
PICKLE LAKE ONTARIO SHOW INVERTED V-TYPE SOUNDINGS...WITH INVERSION
HEIGHTS AROUND 3000 FEET. THIS DRYING WITH LOW INVERSION HEIGHTS
SUGGESTS THAT ANY LES ACCUMULATIONS OVERNIGHT IN THE EASTERN CWA
WILL BE SMALL...AND COVERAGE WILL BE LIMITED. CURRENTLY MOST CLOUD
COVER IS DIMINISHING ACROSS THE WESTERN CWA...WITH THE EXCEPTION OF
LAKE EFFECT CLOUDS. REGWRF...RUC...AND GFS ALL HINT AT A COUPLE OF
LES BANDS DEVELOPING EAST OF MARQUETTE...MOVING TOWARDS GRAND MARAIS
AND LASTING THROUGH THE NIGHT. SOME CLOUD BANDS ARE OBSERVED ON THE
VISIBLE SATELLITE AT THE MOMENT OVER EASTERN LAKE SUPERIOR...AND I
EXPECT THESE TO BECOME MORE ORGANIZED AFTER DARK. THE MAIN
DIFFERENCE OBSERVED BETWEEN EACH OF THE MODEL FIELDS IS THE AMOUNT
OF LINGERING MOISTURE...THE NAM PUSHES ALL OF THE MOISTURE OUT OF
THE REGION BY 00Z TONIGHT...WHICH PUTS THE END TO LES. THIS SEEMS TO
BE THE OUTLIER...HOWEVER. WITH THE WINDS OUT OF THE NORTHWEST THIS
EVENING...EXPECT SOME LIGHT LAKE EFFECT SNOW SHOWERS TO CONTINUE
FROM MARQUETTE MOVING EASTWARD THROUGH THE NIGHT AS THE DRIER AIR
WORKS IN. ANOTHER FAVORABLE FACTOR IS THAT LES TYPICALLY RAMPS UP
DURING THE NIGHT HOURS...AND AS A RESULT WILL KEEP IN SOME SHOWERS
EAST OF MARQUETTE. THIS LES SHOULD END BY EARLY MORNING HOWEVER...AS
WINDS BECOME WESTERLY...PUSHING ANY REMAINING BANDS INTO ONTARIO OR
ENDING THEM ALL TOGETHER. FOR THE WESTERN CWA ONLY HAVE LAKE INDUCED
CLOUD COVER LASTING THROUGH AROUND 6Z AS A RESULT OF THE NORTHWEST
WINDS...THEN TAPERING OFF AS THE WINDS SHIFT TO THE SOUTHWEST. CLOUD
COVER IN THE INTERIOR WEST TONIGHT...ALLOWING FOR DECENT RADIATIONAL
COOLING. AS A RESULT...TEMPERATURES NEAR THE WISCONSIN BORDER SHOULD
FALL INTO THE SINGLE DIGITS TONIGHT.
AS FOR FRIDAY...WITH THE HIGH PRESSURE RIDGE OVERHEAD AND THE DRY
AIRMASS IN PLACE...EXPECT A MOSTLY SUNNY DAY. TEMPERATURES WILL
STRUGGLE TO REACH INTO THE 30S INLAND AS A RESULT OF MORE STABLE
CONDITIONS. EXPECT WINDS TO INCREASE THROUGHOUT THE DAY AS PRESSURE
GRADIENT BETWEEN HIGH PRESSURE RIDGE AND A LOW PRESSURE SYSTEM
CENTERED OVER MANITOBA TIGHTENS.
.LONG TERM 00Z SAT ONWARD...
THE NAM SHOWS A 500 MB SHORTWAVE RIDGE OVER THE UPPER GREAT LAKES
00Z SAT WITH A TROUGH IN THE NORTHERN ROCKIES AND A CLOSED LOW AND
TROUGH IN THE DESERT SW 00Z SAT. THE TROUGH PULLS EAST INTO THE
NORTHERN PLAINS 00Z SUN WITH THE SOUTHERN TROUGH GETTING CUT OFF AND
REMAINING IN THE DESERT SW. NAM SHOWS SOME 850-500 MB Q-VECTOR
CONVERGENCE AND MOISTURE SAT INTO SUN MORNING. NAM ALSO SHOWING SOME
ISENTROPIC LIFT AND MOISTURE ON I280K-I295K SURFACES ON SAT BEFORE
THE LIFT MOVES OFF FOR SAT NIGHT INTO SUNDAY. GFS SHOWS SOME 850-500
MB Q-VECTOR CONVERGENCE MOVING THROUGH FRI NIGHT THROUGH SAT EVENING
BEFORE THIS MOVES OUT. STILL LOOKS LIKE A 3-6 INCH SNOW EVENT FOR
THE CWA WITH THE MOST SNOW IN THE CENTRAL CWA AND LESSER AMOUNTS IN
THE WEST AND EAST. THE EAST WOULD HAVE SOME RAIN MIXED IN AND THE
WEST WOULD BE ON THE WESTERN EDGE OF THE PCPN SHIELD. LAKE EFFECT
THEN TAKES OVER ON SUNDAY FOR NORTH AFFECTED LAKE EFFECT SNOW BELTS.
OVERALL DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES OR WEATHER.
IN THE EXTENDED...THE GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
NORTHERN PLAINS 00Z MON DOWN INTO THE SOUTHERN ROCKIES. THIS TROUGH
MOVES INTO THE UPPER GREAT LAKES 00Z TUE. THIS TROUGH THEN SPLITS
WITH THE NORTHERN PART OF THE TROUGH OVER THE LOWER GREAT LAKES
WHILE THE SOUTHERN PART IS OVER THE SOUTHERN PLAINS 00Z WED. A BROAD
TROUGH THEN SETS UP ACROSS THE NORTHERN U.S. 00Z THU ASSOCIATED WITH
THE CIRCUMPOLAR VORTEX OVER CENTRAL AND NORTHERN CANADA WITH THE
TROUGH AXIS REMAINING OFF TO THE WEST OF THE AREA 00Z FRI. WHAT THIS
WILL MEAN IS COLDER WEATHER IS ON THE WAY WITH LAKE EFFECT SNOW
BEING THE MAIN WEATHER TYPE FOR THIS FORECAST AND COLDER THAN NORMAL
TEMPERATURES. 850 MB TEMPERATURES GET DOWN TO -14C ON MONDAY INTO
TUESDAY WITH THE GFS WITH A WARMUP FOR WED...BEFORE A REINFORCING
SHOT OF COLD AIR ARRIVES FOR THU AS A COLD FRONT MOVES THROUGH.
OVERALL...DID NOT CHANGE MUCH EXCEPT TO BUMP UP POPS ON THURSDAY IN
LAKE EFFECT AREAS WITH THE COLDER AIR.
&&
.AVIATION /FOR 06Z TAF ISSUANCE/
WITH 900 MB TEMPS NEAR -11C...THERE IS CURRENTLY ENOUGH INSTABILITY
TO SUSTAIN LAKE CLOUDS. RUC 925-900 MB RH FCST AND RECENT TRENDS
SUGGEST THAT CLEARING WILL BE SLOW TO ADVANCE THIS EVENING...KEEPING
KIWD/KCMX NEAR THE EDGE OF THE CLOUD AREA. VFR CONDITIONS SHOULD
THEN PREVAIL THE REST OF THE NIGHT INTO FRI.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
HIGH PRESSURE RIDGE OVER LAKE SUPERIOR WILL KEEP CONDITIONS ON THE
LAKE QUIET OVERNIGHT...WITH FLOW BEING GENERALLY NORTHWEST. AS THE
RIDGE MOVES OUT...A LOW PRESSURE SYSTEM CENTERED OVER MANITOBA WILL
DRAG A TROUGH ACROSS LAKE SUPERIOR. AS IT PROGRESSES EASTWARD...THE
PRESSURE GRADIENT WILL STRENGTHEN. AS A RESULT...GALES TO 35-40
KNOTS ARE EXPECTED ON THE LAKE FROM FRIDAY THROUGH SATURDAY MORNING.
WESTERN LAKE SUPERIOR NEAR ISLE ROYALE AND NORTH CENTRAL LAKE
SUPERIOR WILL SEE THE START OF THE GALES FRIDAY AFTERNOON...AND ON
FRIDAY NIGHT THE EASTERN ZONES. ALL OF THE GALE FORCE WINDS SHOULD
END BY SATURDAY MORNING. WINDS WILL CONTINUE TO GUST TO AROUND 30
KNOTS SATURDAY AFTERNOON...BEFORE DECREASING TO LESS THAN 20 KNOTS
FOR THE REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 10 AM EST SATURDAY FOR
LSZ266-267.
GALE WARNING FROM 10 AM THIS MORNING TO 7 AM EST SATURDAY FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MCB
LONG TERM...07
AVIATION...TITUS
MARINE...MCB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
352 AM EST FRI DEC 2 2011
.SYNOPSIS...
A QUICK-MOVING COLD FRONT WILL SWEEP THROUGH THE REGION TODAY
WITH SCATTERED TO NUMEROUS SNOW SHOWERS AND POSSIBLE SNOW
SQUALLS. THIS FRONT WILL BRING A POTENTIAL LIGHT SNOW
ACCUMULATION ACROSS NORTHERN NEW YORK LATE THIS MORNING INTO
EARLY THIS AFTERNOON...AND ACROSS NORTHERN VERMONT DURING THE
EARLY TO MID AFTERNOON HOURS. SKIES CLEAR TONIGHT WITH HIGH
PRESSURE BUILDING ACROSS THE NORTH COUNTRY. THIS WILL SET UP A
CHILLY NIGHT WITH LOWS IN THE TEENS TO LOWER 20S. HIGH PRESSURE
AND DRY WEATHER CONTINUE FOR THE WEEKEND WITH SEASONABLY COOL
TEMPERATURES ON SATURDAY MODERATING TO ABOVE NORMAL BY SUNDAY ON
GUSTY SOUTH WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 312 AM EST FRIDAY...MID-LEVEL CLOUDS ARE GRADUALLY
OVERSPREADING THE NORTH COUNTRY EARLY THIS MORNING IN ASSOCIATION
WITH UPSTREAM TROUGH AND COLD FRONT ACROSS SERN ONTARIO INTO
LOWER MICHIGAN. UPR TROUGH IS INITIALLY POSITIVE TILT...BUT
BECOMES MORE NEUTRAL TODAY AND SWINGS RAPIDLY THRU THE NORTH
COUNTRY AS A RATHER VIGOROUS WAVE THIS AFTN. NOT MUCH CHANGE FROM
PREVIOUS FCST...WITH BEST THREAT FOR SNOW SHOWERS FROM 14-17Z IN
THE SAINT LAWRENCE VALLEY...16-19Z IN THE ADIRONDACKS...17-21Z IN
THE CHAMPLAIN VALLEY...AND 18-22Z ACROSS THE REST OF VERMONT. THE
SNOW SHOWERS MAY BEGIN AS SOME LIGHT RAIN/SNOW IN THE VALLEY
LOCATIONS WITH SURFACE TEMPERATURES CLOSE TO 40 DEGREES...BUT
SHOULD CHANGE OVER TO SNOW AS THE PRECIPITATION CONTINUES TO
FALL. NARROW AREAS OF 35-40 DBZ MODEL REFLECTIVITY INDICATED IN
3-KM HRRR AND 4-KM LOCAL WRF RUN ASSOCIATED WITH POSSIBLE SNOW
SQUALL ACTIVITY. NOT MUCH SFC BASED INSTABILITY...BUT STEEP LAPSE
RATES AND STRONG DEEP- LAYER VORTICITY ADVECTION COULD BE
SUFFICIENT TO ORGANIZE BAND OF SNOW SQUALLS ACROSS NRN NY INTO
NRN VT TODAY. GREATEST COVERAGE OF SNOW SHOWERS WILL LIKELY BE
ACROSS NORTHERN NEW YORK AND INTO THE HIGHER ELEVATIONS OF
NORTHERN VERMONT. ACCUMULATIONS WILL BE LIGHT...GENERALLY LESS
THAN AN INCH...ALTHOUGH SOME OF THE HIGHER ELEVATIONS OF THE
GREEN MOUNTAINS COULD SEE UP TO 2 INCHES. THIS MAY ACCUMULATE
QUICKLY IN ANY SQUALLS...AND RESULT IN SLOW TRAVEL CONDITIONS FOR
A BRIEF TIME WITH LOW VSBY. HAVE HIGHLIGHTED THREAT IN THE
HAZARDOUS WEATHER OUTLOOK. HIGH TEMPERATURES WILL BE REACHED
BEFORE THE ONSET OF PRECIPITATION...GENERALLY MID TO UPPER
30S...WITH SOME LOW 40S IN THE CHAMPLAIN VALLEY. TEMPERATURES
WILL FALL QUICKLY WITH ONSET OF PCPN THROUGH THE 30S...AND INTO
THE 20S AFTER THE PASSAGE OF THE FRONT. THERE COULD ALSO BE A
PERIOD OF GUSTY NORTHWEST WINDS AFTER THE PASSAGE OF THE COLD
FRONT LATE FRIDAY AFTERNOON AND EVENING WITH SOME GUSTS 15-30
MPH.
CLEARING SKIES AND LIGHTER WINDS TONIGHT WITH STRONG SFC
ANTICYCLONE CRESTING OVER THE NORTH COUNTRY AT 12Z SATURDAY. LOW
TEMPERATURES GENERALLY IN THE TEENS...EXCEPT LOW 20S IN THE
CHAMPLAIN VALLEY. COULD SEE AN ISOLD READING IN THE UPR SINGLE
DIGITS IN THE NRN ADIRONDACKS...INCLUDING AT KSLK.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 312 AM EST FRIDAY...RIDGE OF HIGH PRESSURE IN PLACE FOR
SATURDAY...AND FEATURE WILL TRANSLATE SLOWLY EASTWARD TO THE GULF
OF MAINE LATE IN THE DAY. THIS WILL ALLOW AIR MASS TO MODERATE
WITH DEVELOPING SOUTH WINDS 5-10 MPH BY AFTN. LOOKING AT DRY
WEATHER...MOSTLY SUNNY SKIES AND SEASONABLE HIGH TEMPS FOR EARLY
DECEMBER IN THE MID-UPR 30S.
SOUTH TO SOUTHWEST GRADIENT FLOW PICKS UP SATURDAY NIGHT AND
ESPECIALLY ON SUNDAY. THESE WINDS AND PASSING MID-UPR CLOUDS WILL
KEEP LOW TEMPERATURES A BIT MILDER FOR SATURDAY NIGHT...AND THEN
TEMPS REBOUNDING INTO THE UPR 40S FOR SUNDAY. SOUTH WINDS COULD
BE RATHER GUSTY SUNDAY...GENERALLY 15-25 MPH WITH GUSTS TO 35 MPH
POSSIBLE PER 00Z NAM MODEL SOUNDINGS. A COLD FRONT WILL BE MOVING
EWD THRU THE GREAT LAKES REGION LATE IN THE DAY. AT THIS TIME
HELD OFF ON ANY PRECIPITATION ASSOCIATED WITH THIS
FEATURE...THOUGH CLOUDS WILL BE ON THE INCREASE LATE SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 345 AM EST FRIDAY...LOW PRESSURE SITUATED TO OUR WEST ON
SUNDAY EVENING WILL LIFT NORTH INTO CANADA OVERNIGHT...WEAK COLD
FRONT ASSOCIATED WITH THIS LOW WILL CROSS OUR REGION THOUGH
LIMITED MOISTURE ASSOCIATED WITH THIS FEATURE SO WILL ONLY
MENTION CHANCE POPS AT THIS TIME. AFOREMENTIONED FRONT WILL STALL
OUT TO SOUTHEAST AND SEVERAL WAVES OF MOISTURE WILL RIDE ALONG
THIS FRONT BRINGING MORE PRECIPITATION TO THE REGION. THE GFS AND
ECMWF BOTH SHOW THIS SCENARIO...BUT THE GFS SHOWS IT ENDING
SOONER THAN THE ECMWF. THE ECMWF HANGS ONTO THE PRECIP ALL THE
WAY THROUGH THURSDAY AND THE GFS ENDS THE PRECIP ON TUESDAY
NIGHT. AT THIS TIME HAVE MENTIONED HIGHEST POPS FOR MONDAY NIGHT.
TEMPERATURES WILL CONTINUE TO RUN WARMER THAN NORMAL THROUGH THE
PERIOD. RIGHT NOW LOOKS LIKE THE MAJORITY OF THE PRECIP WE GET
NEXT WEEK WILL BE RAIN WITH A POSSIBLE CHANGEOVER TO SNOW AT THE
END OF THE EVENT.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
THROUGH 06Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH 15Z
FRIDAY...AS A RIDGE OF HIGH PRESSURE SLOWLY MOVES EAST OF THE
REGION...WITH SOME AREAS OF MVFR CEILINGS ACROSS NORTHERN NEW
YORK. AN UPPER TROUGH WILL APPROACH THE REGION DURING THE DAY
TODAY. EXPECTING AREAS OF IFR/MVFR IN LIGHT SNOW DEVELOPING
ACROSS NORTHERN NEW YORK BETWEEN 16Z-18Z FRIDAY...AND THEN MOVING
INTO VERMONT BETWEEN 19Z-21Z FRIDAY. CONDITIONS WILL CLEAR UP BY
ABOUT 00Z AND VFR RETURNS.
OUTLOOK 06Z SATURDAY THROUGH TUESDAY...MAINLY VFR CONDITIONS
EXPECTED THROUGH THE PERIOD...AS A RIDGE OF HIGH PRESSURE WILL BE
OVER THE REGION. SOME GUSTY SOUTHERLY WINDS ARE POSSIBLE ON
SUNDAY DURING THE DAYTIME HOURS. AREAS OF MVFR/IFR CONDITIONS
POSSIBLE IN RAIN AND SNOW SHOWERS MONDAY AND TUESDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...NEILES
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
337 AM EST FRI DEC 2 2011
.SYNOPSIS...
A QUICK-MOVING COLD FRONT WILL SWEEP THROUGH THE REGION TODAY
WITH SCATTERED TO NUMEROUS SNOW SHOWERS AND POSSIBLE SNOW SQUALLS.
THIS FRONT WILL BRING A POTENTIAL LIGHT SNOW ACCUMULATION ACROSS
NORTHERN NEW YORK LATE THIS MORNING INTO EARLY THIS
AFTERNOON...AND ACROSS NORTHERN VERMONT DURING THE EARLY TO MID
AFTERNOON HOURS. SKIES CLEAR TONIGHT WITH HIGH PRESSURE BUILDING
ACROSS THE NORTH COUNTRY. THIS WILL SET UP A CHILLY NIGHT WITH
LOWS IN THE TEENS TO LOWER 20S. HIGH PRESSURE AND DRY WEATHER
CONTINUE FOR THE WEEKEND WITH SEASONABLY COOL TEMPERATURES ON
SATURDAY MODERATING TO ABOVE NORMAL BY SUNDAY ON GUSTY SOUTH
WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 312 AM EST FRIDAY...MID-LEVEL CLOUDS ARE GRADUALLY
OVERSPREADING THE NORTH COUNTRY EARLY THIS MORNING IN ASSOCIATION
WITH UPSTREAM TROUGH AND COLD FRONT ACROSS SERN ONTARIO INTO LOWER
MICHIGAN. UPR TROUGH IS INITIALLY POSITIVE TILT...BUT BECOMES MORE
NEUTRAL TODAY AND SWINGS RAPIDLY THRU THE NORTH COUNTRY AS A
RATHER VIGOROUS WAVE THIS AFTN. NOT MUCH CHANGE FROM PREVIOUS
FCST...WITH BEST THREAT FOR SNOW SHOWERS FROM 14-17Z IN THE SAINT
LAWRENCE VALLEY...16-19Z IN THE ADIRONDACKS...17-21Z IN THE
CHAMPLAIN VALLEY...AND 18-22Z ACROSS THE REST OF VERMONT. THE SNOW
SHOWERS MAY BEGIN AS SOME LIGHT RAIN/SNOW IN THE VALLEY LOCATIONS WITH
SURFACE TEMPERATURES CLOSE TO 40 DEGREES...BUT SHOULD CHANGE OVER
TO SNOW AS THE PRECIPITATION CONTINUES TO FALL. NARROW AREAS OF
35-40 DBZ MODEL REFLECTIVITY INDICATED IN 3-KM HRRR AND 4-KM LOCAL
WRF RUN ASSOCIATED WITH POSSIBLE SNOW SQUALL ACTIVITY. NOT MUCH
SFC BASED INSTABILITY...BUT STEEP LAPSE RATES AND STRONG DEEP-
LAYER VORTICITY ADVECTION COULD BE SUFFICIENT TO ORGANIZE BAND OF
SNOW SQUALLS ACROSS NRN NY INTO NRN VT TODAY. GREATEST COVERAGE OF
SNOW SHOWERS WILL LIKELY BE ACROSS NORTHERN NEW YORK AND INTO THE
HIGHER ELEVATIONS OF NORTHERN VERMONT. ACCUMULATIONS WILL BE
LIGHT...GENERALLY LESS THAN AN INCH...ALTHOUGH SOME OF THE HIGHER
ELEVATIONS OF THE GREEN MOUNTAINS COULD SEE UP TO 2 INCHES. THIS
MAY ACCUMULATE QUICKLY IN ANY SQUALLS...AND RESULT IN SLOW TRAVEL
CONDITIONS FOR A BRIEF TIME WITH LOW VSBY. HAVE HIGHLIGHTED THREAT
IN THE HAZARDOUS WEATHER OUTLOOK. HIGH TEMPERATURES WILL BE
REACHED BEFORE THE ONSET OF PRECIPITATION...GENERALLY MID TO UPPER
30S...WITH SOME LOW 40S IN THE CHAMPLAIN VALLEY. TEMPERATURES WILL
FALL QUICKLY WITH ONSET OF PCPN THROUGH THE 30S...AND INTO THE 20S
AFTER THE PASSAGE OF THE FRONT. THERE COULD ALSO BE A PERIOD OF
GUSTY NORTHWEST WINDS AFTER THE PASSAGE OF THE COLD FRONT LATE
FRIDAY AFTERNOON AND EVENING WITH SOME GUSTS 15-30 MPH.
CLEARING SKIES AND LIGHTER WINDS TONIGHT WITH STRONG SFC
ANTICYCLONE CRESTING OVER THE NORTH COUNTRY AT 12Z SATURDAY. LOW
TEMPERATURES GENERALLY IN THE TEENS...EXCEPT LOW 20S IN THE
CHAMPLAIN VALLEY. COULD SEE AN ISOLD READING IN THE UPR SINGLE
DIGITS IN THE NRN ADIRONDACKS...INCLUDING AT KSLK.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 312 AM EST FRIDAY...RIDGE OF HIGH PRESSURE IN PLACE FOR
SATURDAY...AND FEATURE WILL TRANSLATE SLOWLY EASTWARD TO THE GULF
OF MAINE LATE IN THE DAY. THIS WILL ALLOW AIR MASS TO MODERATE
WITH DEVELOPING SOUTH WINDS 5-10 MPH BY AFTN. LOOKING AT DRY
WEATHER...MOSTLY SUNNY SKIES AND SEASONABLE HIGH TEMPS FOR EARLY
DECEMBER IN THE MID-UPR 30S.
SOUTH TO SOUTHWEST GRADIENT FLOW PICKS UP SATURDAY NIGHT AND
ESPECIALLY ON SUNDAY. THESE WINDS AND PASSING MID-UPR CLOUDS WILL
KEEP LOW TEMPERATURES A BIT MILDER FOR SATURDAY NIGHT...AND THEN
TEMPS REBOUNDING INTO THE UPR 40S FOR SUNDAY. SOUTH WINDS COULD BE
RATHER GUSTY SUNDAY...GENERALLY 15-25 MPH WITH GUSTS TO 35 MPH
POSSIBLE PER 00Z NAM MODEL SOUNDINGS. A COLD FRONT WILL BE MOVING
EWD THRU THE GREAT LAKES REGION LATE IN THE DAY. AT THIS TIME HELD
OFF ON ANY PRECIPITATION ASSOCIATED WITH THIS FEATURE...THOUGH
CLOUDS WILL BE ON THE INCREASE LATE SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 334 PM EST THURSDAY...AREA OF HIGH PRESSURE MOVES INTO THE
GULF OF MAINE AND THE REGION GETS INTO SOUTHWESTERLY WARM
ADVECTION REGIME. WARMING 850MB TEMPS AND INCREASING CLOUDS
SUNDAY...WITH SLIGHT CHANCE SHOWERS TRENDING IN AREAL COVERAGE
FROM WEST TO EAST LATER SUNDAY INTO SUNDAY NIGHT. HIGHS ON SUNDAY
IN THE MID/UPPER 40S...THOUGH THESE COULD BE CLOSER TO 50 DEGREES
IF FULL MIXING OCCURS. CLOUDY SKIES WILL LIMIT DEGREE OF
NOCTURNAL COOLING SUNDAY NIGHT...WITH LOWS IN THE 30S.
WHILE THE GFS AND ECWMF EXTENDED RANGE DATA SHOW A CLOUDY AND WET
WEATHER PATTERN FOR THE EARLY TO MIDDLE PART OF NEXT WEEK...THERE
STILL ARE DIFFERENCES ON SPECIFIC DETAILS. AN AREA OF LOW
PRESSURE ON MONDAY WILL BRING CHANCE RAIN OR HIGHER TERRAIN SNOW
SHOWERS TO THE NORTH COUNTRY. THE BAROCLINIC ZONE ASSOCIATED WITH
THE STORM ON MONDAY LINGERS ACROSS THE REGION THROUGH TUESDAY AND
WEDNESDAY WITH CONTINUED CHANCES FOR PRECIPITATION AS WAVES OF
LOW PRESSURE MOVE NORTHEASTWARD ALONG IT. RECENT SOLUTIONS HAVE
TRENDED WARMER THROUGH PARTS OR ALL OF THIS EVENT. HAVE KEPT
CHANCE PRECIPITATION PROBABILITIES FOR RAIN OR SNOW SHOWERS GOING
THOUGH MIDWEEK BEFORE TAPERING PRECIPITATION PROBABILITIES DOWN
BY LATE WEEK. TEMPERATURES WILL CONTINUE TO RUN ABOVE AVERAGE
THROUGH THE PERIOD.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
THROUGH 06Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH 15Z
FRIDAY...AS A RIDGE OF HIGH PRESSURE SLOWLY MOVES EAST OF THE
REGION...WITH SOME AREAS OF MVFR CEILINGS ACROSS NORTHERN NEW
YORK. AN UPPER TROUGH WILL APPROACH THE REGION DURING THE DAY
TODAY. EXPECTING AREAS OF IFR/MVFR IN LIGHT SNOW DEVELOPING
ACROSS NORTHERN NEW YORK BETWEEN 16Z-18Z FRIDAY...AND THEN MOVING
INTO VERMONT BETWEEN 19Z-21Z FRIDAY. CONDITIONS WILL CLEAR UP BY
ABOUT 00Z AND VFR RETURNS.
OUTLOOK 06Z SATURDAY THROUGH TUESDAY...MAINLY VFR CONDITIONS
EXPECTED THROUGH THE PERIOD...AS A RIDGE OF HIGH PRESSURE WILL BE
OVER THE REGION. SOME GUSTY SOUTHERLY WINDS ARE POSSIBLE ON
SUNDAY DURING THE DAYTIME HOURS. AREAS OF MVFR/IFR CONDITIONS
POSSIBLE IN RAIN AND SNOW SHOWERS MONDAY AND TUESDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...LOCONTO
AVIATION...NEILES
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
345 AM CST FRI DEC 2 2011
.SHORT TERM...
COMPLICATED FORECAST CONTINUES FOR WEST CENTRAL TEXAS. STRONG COLD
FRONT HAS CLEARED ALL BUT THE EXTREME SOUTHEAST PORTIONS OF THE AREA
AS OF 09Z...WITH ONLY JUNCTION AND MASON HAVING NOT SEEN THE FRONTAL
PASSAGE SO FAR. THE NAM AND THE RUC HAVE BOTH HANDLED THE MOVEMENT
OF THE FRONT IN THE SHORT TERM FAIRLY WELL...AND THEY BOTH PUSH THE
FRONT THROUGH THE REMAINDER OF THE AREA BY 12Z...AND THEN STALL IT
JUST TO THE SOUTH. PRESSURE RISES BEHIND THE FRONT HAVE SLOWLY
DECREASED...BUT THE GUSTY NORTH WINDS CONTINUE. GIVEN THESE
WINDS...AND THE DENSITY OF THE COLDER AIR MASS...WILL ASSUME THAT
THE MODELS ARE CORRECT IN PUSHING THE FRONT THROUGH THE REST OF THE
AREA BEFORE PULLING UP STATIONARY.
MEANWHILE...POTENT UPPER LEVEL STORM SYSTEM APPROACHING FROM THE
SOUTHWEST US WILL LEAD TO INCREASING WARM ADVECTION UP AND OVER THE
FRONTAL BOUNDARY...REACHING 40 KTS BY 00Z AND OVER 50 KTS BY
MIDNIGHT. DRIZZLE AND LIGHT RAIN HAS ALREADY BEEN DEVELOPING...AND
THIS WILL CONTINUE AS THIS ISENTROPIC LIFT STRENGTHENS. HAVE
INCREASED POPS FOR TODAY AND TONIGHT. THIS WARM AND MOIST AIR MASS
WILL RIDE UP AND OVER THE COLDER AIR AT THE SURFACE...LEAVING THE
BOUNDARY TO THE SOUTH. HOWEVER...AS THE WARM ADVECTION
INTENSIFIES...THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTHWARD THIS
EVENING...ALTHOUGH HOW FAR NORTH IS STILL A BIG QUESTION. IN ANY
CASE...DONT EXPECT TEMPERATURES TO DROP MUCH TONIGHT...AND ACROSS
MOST OF THE AREA..TEMPERATURES WILL ACTUALLY CLIMB SUBSTANTIALLY
OVERNIGHT.
07
.LONG TERM...
A COLD AND UNSETTLED PATTERN WILL CONTINUE THROUGH MUCH OF THE
EXTENDED FORECAST. A MODEST WARM UP CAN BE EXPECTED ON SATURDAY AS
WARM FRONT LIFTS NORTH THROUGH WEST CENTRAL TEXAS. HIGH TEMPERATURES
WILL RANGE FROM NEAR 60 NORTH...TO NEAR 70 SOUTH. IN THE
MEANTIME...A LARGE UPPER LEVEL TROUGH WILL BE LOCATED ACROSS THE
DESERT SOUTHWEST...AND AN ARCTIC COLD FRONT WILL BE LOCATED OVER
THE SOUTHERN PLAINS. AN UPPER LEVEL SHORTWAVE TROUGH WILL TRACK
ACROSS THE NORTHERN PLAINS SATURDAY HELPING TO SEND THIS COLD
FRONT THROUGH WEST CENTRAL TEXAS SATURDAY NIGHT. SHOWERS WILL BE
POSSIBLE ALONG AND AHEAD OF THE BOUNDARY...AND THIS IS REFLECTED
IN THE CURRENT GRIDS. COLD AIR ADVECTION...CLOUD COVER AND LIGHT
RAIN WILL HELP TO KEEP TEMPERATURES DOWN ON SUNDAY. DROPPED HIGH
TEMPERATURES A FEW DEGREES...GENERALLY IN THE UPPER 30S TO MID
40S...AND THESE MAY NEED TO BE LOWERED ON FUTURE SHIFTS.
ON SUNDAY NIGHT...AFOREMENTIONED UPPER LEVEL TROUGH REMAINS ACROSS
THE DESERT SOUTHWEST...WHILE ANOTHER UPPER LEVEL SHORTWAVE TROUGH
SKIRTS ACROSS THE CENTRAL PLAINS. THIS WILL HELP TO SEND A
REINFORCING SHOT OF COLDER AIR INTO THE AREA...WITH NORTH WINDS
INCREASING MONDAY MORNING AND COLD AIR FILTERING IN. IN
ADDITION...UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE ACROSS
THE AREA IN ADVANCE OF THE MAIN UPPER LEVEL TROUGH LOCATED OVER
THE SOUTHWEST STATES. THIS WILL LIKELY PRODUCE LIGHT PRECIPITATION
ACROSS THE AREA SUNDAY NIGHT AND MONDAY. THE MAIN QUESTION THEN
BECOMES...WHAT TYPE OF PRECIPITATION. MODEL SOUNDINGS AND
700MB/850MB TEMPERATURES ARE INDICATING A RAIN/SNOW MIX ACROSS THE
NORTHERN HALF OF THE AREA EARLY MONDAY...THEN TRANSITIONING TO
RAIN/SNOW ACROSS MUCH OF THE AREA BY LATE MONDAY...AND MOSTLY SNOW
ACROSS THE NORTHERN COUNTIES. THIS SCENARIO IS REFLECTED IN THE
CURRENT FORECAST PACKAGE. AT THIS TIME ANY ACCUMULATIONS SHOULD BE
LIGHT...BUT A LOT OF UNCERTAINTY REMAINS IN THE AMOUNT OF
PRECIPITATION AND THE PRECIPITATION TYPE SUNDAY AND MONDAY. HIGH
TEMPERATURES ON MONDAY WILL BE WELL BELOW NORMAL...RANGING FROM
THE MID 30S NORTH...TO NEAR 40 SOUTH. GIVEN THE FRIGID AIRMASS AND
EXPECTED CLOUD COVER...THE CURRENT HIGH TEMPERATURES IN THE
FORECAST MAY BE A BIT HIGH.
MODELS CONTINUE TO HANG THE UPPER LEVEL TROUGH WEST OF THE
AREA...BEFORE FINALLY SWINGING IT THROUGH LATE TUESDAY. INTRODUCED
SLIGHT CHANCE POPS ACROSS THE AREA MONDAY NIGHT...BEFORE CONDITIONS
IMPROVE TUESDAY MORNING. ANY PRECIPITATION THAT DOES OCCUR WILL
LIKELY FALL AS LIGHT SNOW. ANOTHER VERY COLD DAY IS LIKELY ON
TUESDAY...AND DROPPED TEMPERATURES A FEW DEGREES. A SLOW WARM UP
WILL ENSUE BY THE MIDDLE OF NEXT WEEK...WITH CLOSER TO NORMAL
TEMPERATURES RETURNING BY THURSDAY.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 38 38 63 32 39 / 60 60 60 20 30
SAN ANGELO 44 44 66 35 42 / 50 60 50 20 20
JUNCTION 55 55 69 40 44 / 40 60 40 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/DANIELS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
348 AM CST FRI DEC 2 2011
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
347 AM CST FRI DEC 2 2011
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR AFTER MIDNIGHT TONIGHT
THROUGH SUNDAY MORNING AND POSSIBLE HAZARDS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH OVER SOUTHWEST CANADA...RIDGING OUT
AHEAD OVER THE NORTHERN PLAINS INTO MANITOBA...AND TROUGHING OVER
THE LAKE MICHIGAN AREA. ALSO OF NOTE IS IN THE SOUTHERN STREAM OF AN
UPPER LOW OVER THE DESERT SOUTHWEST. THE FORECAST AREA LIES IN
SUBSIDENCE IMMEDIATELY BEHIND THE LAKE MICHIGAN TROUGH...PROMOTING
HIGH PRESSURE AT THE SURFACE. IN FACT...THE SUBSIDENCE AND DRYING
HAS BEEN ENOUGH TO RESULT IN CLEAR SKIES OVER THE AREA. UPSTREAM 00Z
SOUNDINGS FROM INL AND ABR REFLECT THE DRYING WELL WITH PRECIPITABLE
WATER VALUES UNDER TWO TENTHS OF AN INCH. THE COMBINATION OF THE
CLEAR SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES TO DROP INTO
THE TEENS TO MID 20S. TO THE NORTHWEST...A STREAM OF UPPER LEVEL
MOISTURE CAN BE SEEN ACROSS THE NORTHERN PLAINS INTO SOUTH CENTRAL
CANADA ON WATER VAPOR....AHEAD OF THE UPPER TROUGH THERE...WHICH IS
MANIFESTING ITSELF INTO A LARGE ALTOSTRATUS AND CIRROSTRATUS DECK.
TO THE SOUTHWEST...850MB WINDS HAVE BEEN INCREASING OUT OF THE SOUTH
OVER TEXAS DOWNSTREAM OF THE UPPER LOW...BRINGING GULF OF MEXICO
MOISTURE NORTHWARD TOWARDS OKLAHOMA AS SEEN IN GOES PRECIPITABLE
WATER PLOTS.
TODAY AND TONIGHT...A WARM ADVECTION PATTERN LOOKS TO DEVELOP OVER
THE AREA IN RESPONSE TO THE UPPER TROUGH OVER SOUTHWEST CANADA
SPLITTING INTO TWO...WHERE ONE PIECE MARCHES EAST INTO NORTHWEST
ONTARIO AND NORTH DAKOTA BY 12Z SATURDAY. THE OTHER PIECE DIGS SOUTH
TOWARDS THE LAS VEGAS AREA...CAUSING THE CURRENT UPPER LOW IN
ARIZONA TO GET PUSHED EAST INTO NEW MEXICO. CONDITIONS WILL REMAIN
DRY TODAY GIVEN PLENTIFUL DRY AIR AROUND AS SEEN FROM 00Z SOUNDINGS.
IN FACT...SKIES SHOULD STAY CLEAR TO 00Z. WINDS ARE LIKELY TO
INCREASE...THOUGH...AS THE PRESSURE GRADIENT TIGHTENS UP BEHIND THE
DEPARTING SURFACE RIDGE. TONIGHT IS A DIFFERENT STORY. THE SOUTHERLY
RETURN FLOW SEEN OCCURRING OVER TEXAS NOW IS FORECAST TO EXPAND AND
INTENSIFY TONIGHT...RUNNING FROM DEEP SOUTH TEXAS INTO KANSAS...THEN
NORTHEAST INTO THE FORECAST AREA BY 06Z. 850MB WINDS IN THIS ZONE
ARE PROGGED BETWEEN 40-50 KT. PRECIPITABLE WATER VALUES RESPOND BY
JUMPING FROM AROUND 0.25 INCH AT 00Z TO 0.5-0.8 INCHES AT 12Z...
HIGHEST IN THE SOUTHEASTERN PORTION OF THE FORECAST AREA. 0.75
INCHES REPRESENTS 200 PERCENT OF NORMAL. AS THE DEEPER MOISTURE
ISENTROPICALLY LIFTS INTO THE COLDER AIRMASS OVER THE AREA...
ANTICIPATING PRECIPITATION TO BREAK OUT. MODELS ARE IN VERY GOOD
AGREEMENT ON THIS OCCURRING...WITH THE HIGHEST CONSENSUS OVER THE
SOUTHEASTERN TWO-THIRDS OF THE AREA. PLACED 80-100 PERCENT CHANCES
IN THE SOUTHEAST HALF...THEN TRENDED DRIER HEADING UP TO THE
NORTHWEST INTO LOWER PRECIPITABLE WATER VALUES. P-TYPE A LITTLE
TRICKY AS A SURGE OF WARMER AIR ALSO ACCOMPANIES THE MOISTURE SURGE.
850MB TEMPS ARE PROGGED TO WARM TO 0-2C OVER THE SAME AREA WITH THE
HIGHEST PRECIPITABLE WATER. SHOULD BE MOSTLY A RAIN/SNOW SCENARIO AS
SURFACE TEMPERATURES WARM OVERNIGHT...BUT COULD SEE FREEZING RAIN
TOO IF SURFACE TEMPERATURES HAVE NOT WARMED ABOVE FREEZING OR FROM
NOT ENOUGH ICE PRESENT ALOFT YET. ANY SNOW/ICE ACCUMULATION LOOKS
MINIMAL TONIGHT. HAVE NOT INCLUDED ANY FREEZING RAIN/DRIZZLE BECAUSE
UNCERTAINTY IS JUST TOO HIGH.
SATURDAY THROUGH SUNDAY...MODELS ARE ALL IN VERY GOOD AGREEMENT
KICKING OUT THE UPPER LOW FROM NEW MEXICO AT 12Z SATURDAY NORTHEAST
AS A SHEARING OUT SHORTWAVE. IN ADDITION...THE SHORTWAVE SHOULD GET
ACCELERATED NORTHEAST OVERNIGHT TONIGHT INTO SUNDAY IN RESPONSE TO
MORE TROUGHING DROPPING SOUTH INTO THE NORTHERN PLAINS. THERE ARE
SOME SLIGHT DIFFERENCES WITH RESPECT TO THE ASSOCIATED SURFACE LOW
WITH THE SHORTWAVE...WHICH HAS IMPLICATIONS ON THE TRACK AND
INTENSITY OF THE DEFORMATION PRECIPITATION ON THE NORTH SIDE OF THE
LOW. THE 02.00Z GFS IS THE WEAKEST WITH THE LOW AND FURTHEST
SOUTHEAST...HAVING IT TRACK ACROSS NORTHEAST ILLINOIS AT 12Z SUNDAY.
THE 02.00Z NAM IS FARTHEST NORTHWEST AND FASTEST...CROSSING THE BAY
OF GREEN BAY AT 12Z SUNDAY. THE 02.00Z ECMWF/UKMET IS A COMPROMISE.
FOR NOW FOLLOWED THE COMPROMISE APPROACH...SINCE THE GFS SOLUTION IS
PLAUSIBLE IF MORE CONVECTION CAN OCCUR THAN CURRENTLY PROGGED DOWN
OVER THE SOUTHERN PLAINS. ON THE FLIP SIDE...THERE HAS BEEN QUITE A
BIT OF CONSISTENCY WITH THE ECMWF AND NAM SOLUTIONS. SATURDAY
MORNING SHOULD BE A CONTINUATION OF PRECIPITATION FROM AFTER
MIDNIGHT TONIGHT...DUE TO PERSISTENT ISENTROPIC LIFT. PRECIPITATION
THEN LOOKS TO INTENSIFY IN THE AFTERNOON...PARTICULARLY OVER THE
NORTHWEST HALF OF THE FORECAST AREA...AS THE DEFORMATION AREA OF THE
SURFACE LOW APPROACHES. HEAVIEST PRECIPITATION STILL LOOKS TO OCCUR
SATURDAY EVENING WHEN STRONGEST LOW TO MID-LEVEL FRONTOGENESIS MOVES
ACROSS. IN FACT...CROSS-SECTIONS SHOW THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...SUGGESTING CONVECTIVE
ELEMENTS ARE POSSIBLE. AGAIN...THE HEAVIEST PRECIPITATION LOOKS TO
END UP OVER THE NORTHWEST HALF OF THE FORECAST AREA. WITH SNOW TO
WATER RATIOS LIKELY TO END UP SOMEWHERE AROUND 10 TO 1 AS AN AVERAGE
FOR SATURDAY AND SATURDAY NIGHT...COMBINED WITH QPF AMOUNTS AROUND
0.60 OF AN INCH...TOTAL SNOWFALL WOULD COME OUT TO AROUND 6 INCHES.
GIVEN THAT THE NORTHWEST HALF OF THE FORECAST AREA HAS NOT REALLY
SEEN ITS FIRST SIGNIFICANT SNOW...HAVE ISSUED A WINTER STORM WATCH
FOR THAT AREA. BIGGEST CONCERN OF THE WATCH IS SATURDAY AFTERNOON
AND EVENING...ESPECIALLY TOO WITH THE HOLIDAY SHOPPING/TRAVEL TAKING
PLACE. FOR THE SOUTHEAST END OF THE FORECAST AREA...MAJORITY OF THE
PRECIPITATION MAY FALL AS RAIN OR A RAIN/SNOW MIX AS A SURGE OF WARM
AIR COMES IN. NEW 02.06Z NAM SUGGESTS EVEN A WARMER SURGE. LA CROSSE
COUNTY KEPT OUT OF THE WATCH DUE TO RAIN MIX EXPECTED ON SATURDAY.
FOR BOTH SATURDAY AND SATURDAY NIGHT...INCREASED PRECIPITATION
CHANCES ANYWHERE FROM 10 TO 30 PERCENT GIVEN GOOD CONTINUITY AND
MODEL AGREEMENT. PRECIPITATION SHOULD DIMINISH PRETTY QUICK ON
SUNDAY...THOUGH DID KEEP SOME 20 PERCENT CHANCES GOING IN THE
AFTERNOON FOR CENTRAL WISCONSIN WITH LINGERING UPPER TROUGHING.
CERTAINLY WILL BE COOLER ON SUNDAY WITH SNOW COVER AND 850MB TEMPS
OF -6 TO -8C MOVING IN.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO THE TROUGHING COMING
INTO THE NORTHERN PLAINS ON SUNDAY. GOOD AGREEMENT ON THIS UPPER
TROUGH HEADING EAST INTO THE FORECAST AREA ON MONDAY. HOWEVER...ALL
OF THE BETTER FORCING/MOISTURE APPEAR TO HEAD TO THE NORTH OF THE
AREA. AS SUCH...HAVE CONTINUED A DRY SUNDAY NIGHT AND ONLY KEPT A 20
PERCENT CHANCE IN FOR TAYLOR/CLARK COUNTIES ON MONDAY. COULD SEE
CHANCES BEING COMPLETELY REMOVED FOR MONDAY IF TRENDS CONTINUE.
ALTHOUGH PRECIPITATION LOOKS LIMITED...THE COLD AIR WILL NOT BE.
850MB TEMPS ARE PROGGED TO FALL EVEN FURTHER...DROPPING TO AT LEAST
-8 TO -12C BY 00Z TUESDAY...IF NOT A LITTLE COOLER THAN THAT AS
NOTED BY THE 02.00Z GFS. WENT WITH A BLEND OF GUIDANCE FOR LOWS AND
HIGHS DURING THIS PERIOD...WHICH END UP 5 TO 10 DEGREES COLDER THAN
SATURDAY NIGHT AND SUNDAY.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
347 AM CST FRI DEC 2 2011
AFTER A BUSY EARLY PART TO THE WEEKEND FOR THE WEATHER...MUCH OF THE
EARLY AND MIDDLE PORTION OF NEXT WEEK LOOK QUIET AND COOL. 02.00Z
ECMWF/CANADIAN/GFS/GFS ENSEMBLES ARE IN GOOD AGREEMENT FOR MUCH OF
THE LONG TERM FORECAST INDICATING THE TROUGHING THAT WAS OVER THE
AREA MONDAY LINGERING INTO TUESDAY...THEN JUST GRADUAL DEEP
TROUGHING FORMING OVER MUCH OF CANADA INTO THE NORTHERN U.S. HEADING
INTO THURSDAY. THIS TYPE OF PATTERN SUGGESTS LITTLE MOISTURE TO WORK
WITH AND AS SUCH MODEL QPF FORECASTS ARE PRETTY MUCH NOTHING. NEXT
REAL CHANCE OF PRECIPITATION COMES MAYBE ON THURSDAY NIGHT WITH SOME
HINTS OF SHORTWAVE TROUGHING DIGGING INTO THE WESTERN U.S....
RESULTING IN A WARM ADVECTION PATTERN DOWNSTREAM. STILL...THE
PRECIPITATION CHANCE LOOKS PRETTY SMALL. THE BIG THING IS
TEMPERATURES. 850MB TEMPS ARE PROGGED TO DROP TO ONLY SLOWLY RECOVER
TO -6 TO -8C ON WEDNESDAY...THEN FALL BACK TO -12 TO -18C OR SO FOR
THURSDAY. THEREFORE...TEMPERATURES ARE FORECAST TO STAY BELOW
NORMAL. FOLLOWED A CONSENSUS OF GUIDANCE FOR TEMPERATURES. CANNOT
RULE A PERIOD OF SOME BELOW ZERO TEMPERATURES FOR LOWS TOO...
ESPECIALLY FOR SOME OF THE TYPICAL COLD SPOTS.
&&
.AVIATION...
1110 PM CST THU DEC 1 2011
HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY...BUT QUICKLY SHIFT EAST FRI NIGHT. CLEAR SKIES
AND LIGHT WINDS OVERNIGHT...WITH VFR CONDITIONS CONTINUING FOR MUCH
OF FRIDAY. LOOK FOR SOME AFTERNOON GUSTINESS THANKS TO SUN AIDED
MIXING...MORE SO FOR KRST.
CLOUDS WILL START TO RETURN FRI EVENING...THICKENING AND LOWERING
OVERNIGHT AS A STORM SYSTEM OVER THE SOUTHERN PLAINS STARTS TO
IMPACT THE AREA. MVFR/IFR CEILINGS THEN LOOK LIKELY FOR SAT/SAT
NIGHT AS THE SYSTEM PASSES TO THE SOUTH/EAST. RA/SN CAN ALSO BE
EXPECTED...WITH SEVERAL INCHES OF SNOW ACCUMULATION AND IMPACTS TO
VSBY HEIGHTENED SAT EVENING. CURRENT STORM TRACK WOULD FAVOR KRST
FOR MORE SNOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 AM CST FRI DEC 2 2011
WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR WIZ017-029-032>034.
MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR MNZ079-086>088-094-095.
IA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION..... RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1059 PM MST THU DEC 1 2011
.DISCUSSION...THE VISIBILITIES HAVE IMPROVED SOME OVER THE AREA
BETWEEN KCYS AND KLAR...INCLUDING THE SOUTHERN LARAMIE RANGE. A
SURFACE TROUGH CONTINUES TO DEVELOP OVER FAR EASTERN WYOMING THE
REST OF TONIGHT. THE RESULTING INCREASED SURFACE PRESSURE GRADIENT
SHOULD INCREASE MIXING AND LIMIT THE POTENTIAL FOR DENSE FOG THE
REST OF TONIGHT. FOR THAT REASON...THE DENSE FOG ADVISORY HAS BEEN
CANCELLED FOR THE AREA BETWEEN KCYS AND THE SOUTHERN LARAMIE RANGE.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 1015 PM MST THU DEC 1 2011/...
.AVIATION...06Z TAFS
ONLY PROBLEM AREA THIS EVENING IS GOING TO BE CHEYENNE. LATEST
SATELLITE SHOWING AN EXPANDING AREA OF STRATUS ALONG AND EAST OF
THE SOUTHERN LARAMIE RANGE. THIS IS BRINGING LIFR CNDITIONS TO
KCYS WITH THE EASTERN SLOPES OF THE SOUTHERN LARAMIE RANGE
OBSCURED. LATEST HRRR GUIDANCE KEEPS THIS LAYER IN THROUGH 09Z
WITH CLEARING AFTERWARDS. DECIDED TO KEEP LIFR/IFR CONDITIONS
GOING THROUGH 12Z AS THE AREA IS STILL EXPANDING.
NEXT FRONT LOOKS TO DROP INTO SOUTHEAST WYOMING FRIDAY AFTERNOON
WITH DECREASING FLIGHT CONDITIONS ONCE AGAIN FRIDAY EVENING INTO
SATURDAY.
CLAYCOMB
&&
.PREV DISCUSSION... /ISSUED 905 PM MST THU DEC 1 2011/
UPDATE...
WYDOT WEBCAMS NOW SHOW DENSE FOG FROM CHEYENNE TO AT LEAST THE
INTERSTATE 80 SUMMIT. SEEING REDUCED VISIBILITIES ON INTERSTATE 25
AS WELL OVER WYO HILL. WENT AHEAD WITH A DENSE FOG ADVISORY
THROUGH 12Z/5AM. WINDS FORECAST TO BECOME MORE WESTERLY AFTER THAT
TIME...WHICH SHOULD DISSIPATE OUT THE FOG. UPDATES HAVE BEEN
SENT.
PREV DISCUSSION... /ISSUED 827 PM MST THU DEC 1 2011/
UPDATE...
STARTING TO SEE FOG DEVELOPING OVER THE LARAMIE SUMMIT ON
INTERSTATE 80 BETWEEN CHEYENNE AND LARAMIE. WENT AHEAD AND ISSUED
SPS FOR VISIBILITIES DOWN TO A HALF MILE. WILL WAIT ANOTHER FEW
MINUTES TO SEE IF IT GETS ANY DENSER. LATEST 11-3.9U SATELLITE
IMAGERY SHOWING A FAIRLY CONFINED AREA OF STRATUS OVER THE SUMMIT
AT THIS TIME. WILL CONTINUE TO MONITOR TO SEE IF IT EXPANDS
ANYMORE BEFORE ISSUING A DENSE FOG ADVISORY.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 347 PM MST THU DEC 1 2011/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
TONIGHT...SATELLITE IMAGERY...WSR-88D LOOPS...SURFACE OBSERVATIONS
INDICATE SNOW HAS NEARLY ENDED ACROSS OUR COUNTIES. BASED ON THE NAM
AND GFS SOLUTIONS...WILL LEAVE IN SOME LOW TOKEN POPS FOR THIS
EVENING ACROSS THE SIERRA MADRE...SNOWY AND SOUTHERN LARAMIE RANGES.
PRIMARY CHALLENGE TONIGHT WILL BE MINIMUM TEMPERATURES AS SKIES
CLEAR ALONG WITH FRESH SNOWPACK ALONG WITH LIGHT WINDS.
SURFACE LEE TROUGHING WILL DEVELOP LATE TONIGHT IN OUR COUNTIES IN
RESPONSE TO NEXT APPROACHING SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST. HOWEVER...THIS MINIMAL MIXING IS NOT EXPECTED TO HAVE
MUCH EFFECT ON LOW TEMPERATURES OVERNIGHT. HAVE UNDERCUT GUIDANCE
TEMPERATURES AT MOST LOCATIONS...ESPECIALLY ACROSS THE LARAMIE
VALLEY WHERE CLEAR SKIES...FRESH SNOWPACK...LIGHT WINDS AND THE
ARCTIC AIRMASS WILL PROMOTE EXCELLENT RADIATIONAL
COOLING...PARTICULARLY IN THE HIGH MOUNTAIN VALLEYS AND RIVER VALLEY
LOCATIONS.
FRIDAY...NEXT SHORTWAVE TROUGH ALOFT FAST ON THE HEELS OF THE
CURRENT SHORTWAVE TROUGH. WILL SEE A COLD FRONTAL PASSAGE ACROSS OUR
COUNTIES DURING THE DAY...PRECEDED BY A SURFACE TROUGH PASSAGE.
EXPECT SNOW SHOWERS IN THE AFTERNOON OVER THE NORTHERN LARAMIE
RANGE...SIERRA MADRE RANGE AND SNOWY RANGE DUE TO OROGRAPHICS...DRY
ELSEWHERE.
FRIDAY NIGHT...SHORTWAVE TROUGH ALOFT PASSES ACROSS OUR COUNTIES
WITH THE DEEPER SATURATED LAYER ACROSS OUR WESTERN COUNTIES WEST OF
INTERSTATE 25...COINCIDENT WITH THE BEST UPWARD VERTICAL MOTION
ASSOCIATED WITH THE SHORTWAVE TROUGH. WILL NEED TO WATCH EXPECTED
SNOWFALL AMOUNTS WEST OF A DOUGLAS TO CHEYENNE LINE FOR POSSIBLE
WINTER WEATHER ADVISORY CRITERIA. FOR NOW...HAVE INCREASED SNOW
CHANCES SIGNIFICANTLY ALONG AND WEST OF THE LARAMIE RANGE WITH NEAR
100 PERCENT POPS ACROSS THE HIGHER PEAKS OF THE NORTHERN LARAMIE...
SIERRA MADRE AND SNOWY RANGES...AND LESSER POPS FURTHER EAST AWAY
FROM THE GREATEST DYNAMICS. ANOTHER REINFORCING SHOT OF COLD AIR
ADVECTS IN FROM THE NORTH. WILL INCLUDE AREAS OF BLOWING SNOW IN
AREAS WHERE WINDS AND SNOW LOOK FAVORABLE.
SATURDAY...AS OCCURRED TODAY...SNOW GRADUALLY ENDS FROM NORTH TO
SOUTH AS THE SHORTWAVE TROUGH ALOFT MOVES ACROSS COLORADO. LOOKS
LIKE THE MOTHERLODE OF THE COLD AIRMASS MOVES OVERHEAD IN OUR
COUNTIES WITH PROGGED 700 MB TEMPERATURES NEAR -18 CELSIUS...
THUS HIGH TEMPERATURES ONLY IN THE TEENS AND 20S...WHICH MAY BE
OPTIMISTIC IF CLOUD OPACITY...THICKNESS...IS WELL PRONOUNCED.
SATURDAY NIGHT...NEXT SHORTWAVE TROUGH ALOFT...A HEALTHY LOOKING
ALBERTA CLIPPER SYSTEM...TRACKS OVER MONTANA AND NORTH DAKOTA...
INDUCING SURFACE LOW PRESSURE TO STRENGTHEN ACROSS NORTH DAKOTA AND
INCREASING THE PRESSURE GRADIENT ACROSS OUR COUNTIES. BLUSTERY AND
COLD NIGHT FOR OUR COUNTIES WITH MINIMUM TEMPERATURES IN THE SINGLE
DIGITS BELOW ZERO AND ABOVE ZERO...WITH A FEW LOWER TEENS...AND
DECENT DOWNSLOPE WEST WINDS. WIND CHILL TEMPERATURES OF 15 BELOW
ZERO TO 30 BELOW ZERO ON TAP ACROSS MUCH OF CARBON AND ALBANY
COUNTIES.
LONG TERM...SUNDAY THROUGH THURSDAY...UPPER LEVEL TROUGH WILL DIVE
SOUTH INTO THE NORTHERN PLAINS FROM CANADA ON SUNDAY. THE ASSOCIATED
COLD FRONT WILL MOVE ACROSS THE AREA ON SUNDAY MORNING...THUS
EXPECT MAX TEMPS TO OCCUR SOMETIME IN THE MORNING WITH TEMPS THEN
FALLING THROUGH THE DAY BEHIND THE FRONT. LIGHT SNOW WILL OCCUR
BEHIND THE FRONT WITH NOT MUCH ACCUMULATION EXPECTED OUTSIDE OF
THE MOUNTAINS. VERY COLD TEMPS WILL OCCUR SUNDAY NIGHT AS SKIES
CLEAR SOMEWHAT AND THE UPPER TROUGH MOVES OVERHEAD...USHERING IN
700MB TEMPS OF -20 TO -25C. MONDAY WILL REMAIN QUITE
CHILLY...ALTHOUGH SOME MODERATION IS POSSIBLE WITH MOSTLY CLEAR
SKIES. SFC HIGH PRESSURE BEHIND THE FRONT WILL SLIDE SOUTH OF THE
AREA ON MONDAY NIGHT WITH THE LEESIDE SFC TROUGH DEEPENING THRU
TUESDAY MORNING. WESTERLY WINDS WILL THUS INCREASE AS THIS
OCCURS...AND WILL PERSIST THROUGH TUESDAY NIGHT AHEAD OF THE NEXT
COLD FRONT AND UPPER LEVEL SYSTEM EXPECTED TO AFFECT THE FORECAST
AREA WEDNESDAY AND THURSDAY. SOME LIGHT SNOW IS POSSIBLE WITH
THIS SYSTEM ACROSS MUCH OF THE FORECAST AREA.
FIRE WEATHER...NO FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM/AVIATION...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1015 PM MST THU DEC 1 2011
.AVIATION...06Z TAFS
ONLY PROBLEM AREA THIS EVENING IS GOING TO BE CHEYENNE. LATEST
SATELLITE SHOWING AN EXPANDING AREA OF STRATUS ALONG AND EAST OF
THE SOUTHERN LARAMIE RANGE. THIS IS BRINGING LIFR CNDITIONS TO
KCYS WITH THE EASTERN SLOPES OF THE SOUTHERN LARAMIE RANGE
OBSCURED. LATEST HRRR GUIDANCE KEEPS THIS LAYER IN THROUGH 09Z
WITH CLEARING AFTERWARDS. DECIDED TO KEEP LIFR/IFR CONDITIONS
GOING THROUGH 12Z AS THE AREA IS STILL EXPANDING.
NEXT FRONT LOOKS TO DROP INTO SOUTHEAST WYOMING FRIDAY AFTERNOON
WITH DECREASING FLIGHT CONDITIONS ONCE AGAIN FRIDAY EVENING INTO
SATURDAY.
CLAYCOMB
&&
.PREV DISCUSSION... /ISSUED 905 PM MST THU DEC 1 2011/
UPDATE...
WYDOT WEBCAMS NOW SHOW DENSE FOG FROM CHEYENNE TO AT LEAST THE
INTERSTATE 80 SUMMIT. SEEING REDUCED VISIBILITIES ON INTERSTATE 25
AS WELL OVER WYO HILL. WENT AHEAD WITH A DENSE FOG ADVISORY
THROUGH 12Z/5AM. WINDS FORECAST TO BECOME MORE WESTERLY AFTER THAT
TIME...WHICH SHOULD DISSIPATE OUT THE FOG. UPDATES HAVE BEEN
SENT.
PREV DISCUSSION... /ISSUED 827 PM MST THU DEC 1 2011/
UPDATE...
STARTING TO SEE FOG DEVELOPING OVER THE LARAMIE SUMMIT ON
INTERSTATE 80 BETWEEN CHEYENNE AND LARAMIE. WENT AHEAD AND ISSUED
SPS FOR VISIBILITIES DOWN TO A HALF MILE. WILL WAIT ANOTHER FEW
MINUTES TO SEE IF IT GETS ANY DENSER. LATEST 11-3.9U SATELLITE
IMAGERY SHOWING A FAIRLY CONFINED AREA OF STRATUS OVER THE SUMMIT
AT THIS TIME. WILL CONTINUE TO MONITOR TO SEE IF IT EXPANDS
ANYMORE BEFORE ISSUING A DENSE FOG ADVISORY.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 347 PM MST THU DEC 1 2011/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT.
TONIGHT...SATELLITE IMAGERY...WSR-88D LOOPS...SURFACE OBSERVATIONS
INDICATE SNOW HAS NEARLY ENDED ACROSS OUR COUNTIES. BASED ON THE NAM
AND GFS SOLUTIONS...WILL LEAVE IN SOME LOW TOKEN POPS FOR THIS
EVENING ACROSS THE SIERRA MADRE...SNOWY AND SOUTHERN LARAMIE RANGES.
PRIMARY CHALLENGE TONIGHT WILL BE MINIMUM TEMPERATURES AS SKIES
CLEAR ALONG WITH FRESH SNOWPACK ALONG WITH LIGHT WINDS.
SURFACE LEE TROUGHING WILL DEVELOP LATE TONIGHT IN OUR COUNTIES IN
RESPONSE TO NEXT APPROACHING SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST. HOWEVER...THIS MINIMAL MIXING IS NOT EXPECTED TO HAVE
MUCH EFFECT ON LOW TEMPERATURES OVERNIGHT. HAVE UNDERCUT GUIDANCE
TEMPERATURES AT MOST LOCATIONS...ESPECIALLY ACROSS THE LARAMIE
VALLEY WHERE CLEAR SKIES...FRESH SNOWPACK...LIGHT WINDS AND THE
ARCTIC AIRMASS WILL PROMOTE EXCELLENT RADIATIONAL
COOLING...PARTICULARLY IN THE HIGH MOUNTAIN VALLEYS AND RIVER VALLEY
LOCATIONS.
FRIDAY...NEXT SHORTWAVE TROUGH ALOFT FAST ON THE HEELS OF THE
CURRENT SHORTWAVE TROUGH. WILL SEE A COLD FRONTAL PASSAGE ACROSS OUR
COUNTIES DURING THE DAY...PRECEDED BY A SURFACE TROUGH PASSAGE.
EXPECT SNOW SHOWERS IN THE AFTERNOON OVER THE NORTHERN LARAMIE
RANGE...SIERRA MADRE RANGE AND SNOWY RANGE DUE TO OROGRAPHICS...DRY
ELSEWHERE.
FRIDAY NIGHT...SHORTWAVE TROUGH ALOFT PASSES ACROSS OUR COUNTIES
WITH THE DEEPER SATURATED LAYER ACROSS OUR WESTERN COUNTIES WEST OF
INTERSTATE 25...COINCIDENT WITH THE BEST UPWARD VERTICAL MOTION
ASSOCIATED WITH THE SHORTWAVE TROUGH. WILL NEED TO WATCH EXPECTED
SNOWFALL AMOUNTS WEST OF A DOUGLAS TO CHEYENNE LINE FOR POSSIBLE
WINTER WEATHER ADVISORY CRITERIA. FOR NOW...HAVE INCREASED SNOW
CHANCES SIGNIFICANTLY ALONG AND WEST OF THE LARAMIE RANGE WITH NEAR
100 PERCENT POPS ACROSS THE HIGHER PEAKS OF THE NORTHERN LARAMIE...
SIERRA MADRE AND SNOWY RANGES...AND LESSER POPS FURTHER EAST AWAY
FROM THE GREATEST DYNAMICS. ANOTHER REINFORCING SHOT OF COLD AIR
ADVECTS IN FROM THE NORTH. WILL INCLUDE AREAS OF BLOWING SNOW IN
AREAS WHERE WINDS AND SNOW LOOK FAVORABLE.
SATURDAY...AS OCCURRED TODAY...SNOW GRADUALLY ENDS FROM NORTH TO
SOUTH AS THE SHORTWAVE TROUGH ALOFT MOVES ACROSS COLORADO. LOOKS
LIKE THE MOTHERLODE OF THE COLD AIRMASS MOVES OVERHEAD IN OUR
COUNTIES WITH PROGGED 700 MB TEMPERATURES NEAR -18 CELSIUS...
THUS HIGH TEMPERATURES ONLY IN THE TEENS AND 20S...WHICH MAY BE
OPTIMISTIC IF CLOUD OPACITY...THICKNESS...IS WELL PRONOUNCED.
SATURDAY NIGHT...NEXT SHORTWAVE TROUGH ALOFT...A HEALTHY LOOKING
ALBERTA CLIPPER SYSTEM...TRACKS OVER MONTANA AND NORTH DAKOTA...
INDUCING SURFACE LOW PRESSURE TO STRENGTHEN ACROSS NORTH DAKOTA AND
INCREASING THE PRESSURE GRADIENT ACROSS OUR COUNTIES. BLUSTERY AND
COLD NIGHT FOR OUR COUNTIES WITH MINIMUM TEMPERATURES IN THE SINGLE
DIGITS BELOW ZERO AND ABOVE ZERO...WITH A FEW LOWER TEENS...AND
DECENT DOWNSLOPE WEST WINDS. WIND CHILL TEMPERATURES OF 15 BELOW
ZERO TO 30 BELOW ZERO ON TAP ACROSS MUCH OF CARBON AND ALBANY
COUNTIES.
LONG TERM...SUNDAY THROUGH THURSDAY...UPPER LEVEL TROUGH WILL DIVE
SOUTH INTO THE NORTHERN PLAINS FROM CANADA ON SUNDAY. THE ASSOCIATED
COLD FRONT WILL MOVE ACROSS THE AREA ON SUNDAY MORNING...THUS
EXPECT MAX TEMPS TO OCCUR SOMETIME IN THE MORNING WITH TEMPS THEN
FALLING THROUGH THE DAY BEHIND THE FRONT. LIGHT SNOW WILL OCCUR
BEHIND THE FRONT WITH NOT MUCH ACCUMULATION EXPECTED OUTSIDE OF
THE MOUNTAINS. VERY COLD TEMPS WILL OCCUR SUNDAY NIGHT AS SKIES
CLEAR SOMEWHAT AND THE UPPER TROUGH MOVES OVERHEAD...USHERING IN
700MB TEMPS OF -20 TO -25C. MONDAY WILL REMAIN QUITE
CHILLY...ALTHOUGH SOME MODERATION IS POSSIBLE WITH MOSTLY CLEAR
SKIES. SFC HIGH PRESSURE BEHIND THE FRONT WILL SLIDE SOUTH OF THE
AREA ON MONDAY NIGHT WITH THE LEESIDE SFC TROUGH DEEPENING THRU
TUESDAY MORNING. WESTERLY WINDS WILL THUS INCREASE AS THIS
OCCURS...AND WILL PERSIST THROUGH TUESDAY NIGHT AHEAD OF THE NEXT
COLD FRONT AND UPPER LEVEL SYSTEM EXPECTED TO AFFECT THE FORECAST
AREA WEDNESDAY AND THURSDAY. SOME LIGHT SNOW IS POSSIBLE WITH
THIS SYSTEM ACROSS MUCH OF THE FORECAST AREA.
FIRE WEATHER...NO FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 5 AM FRIDAY FOR WYZ116-WYZ117-WYZ118.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM/AVIATION...RJM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
920 AM EST FRI DEC 2 2011
.SYNOPSIS...
STRONG HIGH PRESSURE CENTERED IN THE PLAINS STATES HAS AN EXTENSION
TO THE MID-ATLANTIC COAST BUT IS AWAITING THE PASSAGE OF A WEAK
COLD FRONTAL PASSAGE THROUGH THE MID-ATLANTIC STATES LATER TODAY.
THE HIGH THEN BUILDS STRONGLY INTO NEW ENGLAND SATURDAY AND EDGES
OFFSHORE MONDAY. A COLD FRONT SHOULD BE STALLING OR DRIFTING EAST
FROM THE APPALACHIAN MOUNTAINS MONDAY THROUGH AT LEAST WEDNESDAY
AS A SERIES OF LOW PRESSURE SYSTEMS TRY TO MOVE NORTHEAST ALONG
THE FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT TO MANY CHANGES WITH THIS UPDATE. A FRONTAL BOUNDARY WILL MOVE
ACROSS NEW ENGLAND TODAY. THIS MAY RESULT IN SOME HIGH CIRRUS THIS
AFTERNOON AS DISCUSSED BY PREVIOUS SHIFTS. LATEST 12Z RUC KEEPS ANY
PRECIP WELL TO OUR NORTH. A CONCERN MAY BE SOME CAA THIS AFTERNOON
BEHIND THE FRONT RESULTING IN THE LOWERING HIGH TEMPERATURES A
TOUCH. CURRENT TEMPERATURES AND DEWPOINTS ALSO HAVE BEEN ADJUSTED SLIGHTLY
BASED ON 14Z METAR OBS. FRONT SHOULD BRING SOUTHERLY WINDS THIS
AFTERNOON SWITCHING TO NORTHWESTERLY, MADE FEW CHANGES TO WIND.
LOWERED WAVE HEIGHTS SLIGHTLY FOR THE NEXT FEW HOURS BASED ON BUOY
OBSERVATIONS WILL MONITOR THROUGHOUT THE DAY WITH RESPECT TO THE
SMALL CRAFT ADVISORY SET TO GO INTO EFFECT LATE THIS
AFTERNOON/TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
TONIGHT IS A CLEAR NIGHT WITH A BIT OF NW BECOMING NORTH BREEZE
DURING THE NIGHT AND TEMPS COOLING TO ABOUT THE SAME VALUES OR
SLIGHTLY LOWER THAN WHAT OCCURRED THIS FROSTY FRIDAY MORNING.
LOWERED THE TEMPS SLIGHTLY IN THE PHL-TTN URBAN CENTERS WITH NORTH
WIND TONIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
FAIR WEATHER IS EXPECTED ACROSS THE AREA THIS WEEKEND AS HIGH
PRESSURE REMAINS IN CONTROL OF THE WEATHER. BOTH THE EC AND GFS
AGREE THAT THE HIGH WILL CREST OVER THE AREA SAT NIGHT AND THEN
MOVE OFF INTO THE NORTH ATLANTIC SUN. SKIES WILL BE MOSTLY CLR
SAT AND PARTLY TO MOSTLY CLR SUN. CLOUDS MAY ARRIVE LATER SUN WITH
THE RETURN FLOW BEHIND THE HIGHBRINGING MOISTURE FROM OFF THE
OCEAN.
A LOW MOVES ACROSS SRN CANADA SUN NGT INTO MON CAUSING A FRONT TO
DROP DOWN FROM THE NORTH. THIS FRONT STALLS ACROSS THE AREA
ALLOWING ANOTHER LOW TO DEVELOP ON IT AND MOVE ACROSS THE AREA MON
NGT INTO WED. THE GFS AND EC OFFER DIFFERENT SOLUTIONS WITH
REGARDS TO HOW MUCH PRECIP ARRIVES AND WHEN. BOTH MODELS HAVE SOME
QPF ARRIVING TUE...BUT THE EC HAS HEAVIER QPF ACROSS THE AREA WED
NIGHT INTO THU WHILE THE GFS HAS THE BULF OF ITS QPF TUE NIGHT
INTO WED. THE OVERNIGHT EXTENDED GRIDS HAVE MADE ONLY SMALL
CHANGES TO THE EARLIER FCST WITH CHC POPS THROUGH MUCH OF THE MON
NGT-THU PERIOD ATTM. A LITTLE SNOW MAY MIX IN WED NIGHT ACROSS THE
NRN AREAS.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR MOSTLY CLEAR. PATCHY THICK CI ESPECIALLY 16Z-20Z...MAINLY
N OF PHL. SCT CLDS 5000-8000 FT EXPECTED WITH THE LATE AFTN CFP.
W GUSTS TO 15 KTS AT 18Z SHIFT NW AROUND 21Z WITH GUSTS 20 KTS...
ISOLATED GUSTS TO 25 KTS POSSIBLE NEAR 23Z/2.
TONIGHT...VFR CLEAR. NW WIND 5 TO 15 KTS BECOMING N DURING THE NIGHT.
PHILADELPHIA SPECIFIC...HIGH CONFIDENCE FCST OF VFR CLEAR THROUGH
17Z WITH A BAND OF CI POSSIBLE 18Z-20Z. WIND AT 18Z W GUST 15 KT.
AFTER 20Z...WSHIFT NW WITH GUSTS 20 KTS AND A FEW SC/CU 6000-8000
FT. LOW PROB ISO NW GUSTS 25 KTS IN THE 21Z-23Z TIME FRAME.
OUTLOOK...
VFR CONDITIONS EXPECTED SAT AND MUCH OF SUN. LOW CLOUDS MAY ARRIVE
BEHIND THE DEPARTING HIGH LATER SUN INTO MON. POOR FLYING CONDITIONS
TUE INTO THU WITH THE NEXT SYSTEM ARRIVING FROM THE MIDWEST STATES.
&&
.MARINE...
TODAY...LIGHT WIND TO START BECOMING INCREASINGLY GUSTY WEST THIS
AFTN.
TONIGHT...SCA ISSUED. MARGINAL CONFIDENCE IN THIS ADVY FOR SCT
GUSTS 22-25 KTS MAINLY IN THE 23Z-05Z TIME FRAME. 44009 SEAS
EXPECTED TO INCREASE TO 5 FT LATER TONIGHT SO HAVE TWO SEGMENTS...
A NJ SEGMENT FOR THIS EVENING AND A LATER LENGTHIER TIME FRAME
SEGMENT FOR THE DELAWARE ATLC WATERS.
NO HEADLINE POSTED YET FOR LOWER DELAWARE BAY. THAT CAN BE ADDED
LATER BY FUTURE SHIFTS IF CONFIDENCE INCREASES.
STRUGGLED TO GET THE GRIDDED GUSTS TO CRITERIA VIA SEVERAL TOOL
APPLICATIONS.
SREF STILL NOT A HINT OF SUSTAINED 25 KT WINDS ALONG OUR COASTS.
OUTLOOK...
HIGH PRESSURE WILL BE ACROSS THE WATERS THIS WEEKEND WITH WINDS
AND SEAS EXECTED TO REMAIN SUB-SCA THROUGH THE PERIOD. THE HIGH
WILL MOVE AWAY EARLY NEXT WEEK WHILE LOW PRESSURE AND A SERIES OF
FRONTS ARRIVE OVER OUR WATERS MON NGT INTO WED. WINDS AND SEAS
WILL EVENTUALLY RISE INTO SCA CRITERIA PROBABLY BY TUE NIGHT AND
THIS WILL PERSIST INTO THU.
&&
.CLIMATE...
DAILY CLI: GED 1203Z-1207Z TRACE OF SNOW IN CLEAR SKY REMOVED FROM
THE 430PM CLI RUN.
RAN THE MONTHLY CLM`S WITH JUST CURSORY CHECK OF THE DATA. IF YOU
NOTICE ANY ERRORS PLEASE GIVE US A CALL.
YOU SAW THE RER`S ISSUED EARLY THURSDAY MORNING REGARDING MONTHLY
AND SEASONAL RANKING OF THE TEMPS/QPF!
LA NINA OHIO VALLEY STORM TRACK CONTS TO LOOK ACTIVE AND MOST
INDICATIONS ARE THAT THE PRECIPITATION EVENT FROM LATE MONDAY INTO
WEDNESDAY WILL AT SOME POINT RAISE THE YEARLY WATER EQUIVALENT
PCPN TOTAL AT KABE TO RECORD VALUES...NEEDING ONLY .16 INCHES TO
EXCEED THE YEARLY RECORD OF 67.69 INCHES.
NOTING THAT PHL AVG TEMP IS HEADED FOR ITS 13TH CONSECUTIVE ABOVE
NORMAL DAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 1 AM EST
SATURDAY FOR ANZ450>453.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EST
SATURDAY FOR ANZ454-455.
&&
$$
SYNOPSIS...DRAG/GORSE
NEAR TERM...GAINES
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...DRAG/O`HARA
MARINE...DRAG/O`HARA
CLIMATE...
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
954 AM EST FRI DEC 2 2011
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A WEAKENING COLD FRONT FROM NORTHERN INDIANA TO SOUTHEAST MISSOURI
WILL MOVE INTO OUR REGION LATER TODAY AND GRADUALLY DISSIPATE. AN
AREA OF HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE OUR WEATHER
TONIGHT AND SATURDAY. RAIN WILL SPREAD INTO OUR REGION LATE
SATURDAY NIGHT AND SUNDAY AS ANOTHER AND STRONGER COLD FRONT MOVES
OUR WAY. SEVERAL MODELS STALL THIS FRONT FROM THE LOWER MISSISSIPPI
VALLEY TO OHIO EARLY NEXT WEEK...KEEPING SOUTHERN SECTIONS VERY
WET. FARTHER NORTH MIXED PRECIP WILL BE THE RULE AS COLDER AIR
SPREADS INTO OUR REGION. FINALLY DRY AND COLD WEATHER WILL BE THE
RULE AFTER THE MIDDLE OF NEXT WEEK AS THE FRONT TO OUR EAST MOVES
EAST AND HIGH PRESSURE OVER THE ROCKIES BUILDS OUR WAY.
&&
.NEAR TERM /REST OF TODAY/...
UPDATE...FORECAST GENERALLY LOOKS TO BE IN GREAT SHAPE. ONLY
NEEDED TO MAKE A FEW MINOR TWEAKS TO ACCOUNT FOR LATEST TRENDS.
BY MIDDAY MODELS SHOW QUITE A BIT OF DRYING AS HIGH PRESSURE
BUILDS INTO THE GREAT LAKES AND DOWNWARD VERTICAL VELOCITIES
OCCUR...SKIES SHOULD BECOME MOSTLY SUNNY EVERYWHERE LATE.
VISIBLE SATELLITE AND OBSERVATIONS INDICATE A LITTLE REMAINING
SNOW COVER ACROSS PARTS OF OUR FAR NORTH AND NORTHEAST WHICH MAY
HOLD TEMPERATURES DOWN THERE JUST A LITTLE. OTHERWISE...WENT NEAR
A MAV/MET BLEND ON TEMPERATURES MOST OTHER AREAS TODAY FOR HIGHS
IN THE 40S.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
MODELS ARE IN GOOD AGREEMENT THIS PERIOD SO USED A BLEND WITH ONLY
MINOR ADJUSTMENTS.
SATURDAY WILL BE MILD AND DRY AS A SOUTHERLY FLOW INCREASES ACROSS
OUR REGION AS THE RESULT OF HIGH PRESSURE OVER THE EASTERN U.S. AND
LOW PRESSURE MOVING FROM THE CENTRAL PLAINS TOWARDS THE GREAT
LAKES.
MODELS THIS RUN ARE A TAD SLOWER IN BEGINNING PRECIP MAINLY LATE
SATURDAY NIGHT AND MAINTAINING IT A LITTLE FARTHER NORTH SUNDAY AND
SUNDAY NIGHT. A COLD FRONT WILL MOVE EAST ACROSS OUR REGION SUNDAY
AND STALL NEAR OR JUST A LITTLE SOUTH OF THE OHIO RIVER SUNDAY
NIGHT. IN MOST CASES...WENT CLOSE TO A MOS BLEND ON TEMPERATURES
AND POPS.
A PERIOD OF MIXED PRECIP POSSIBLE ACROSS OUR NORTH MAINLY LATE
SUNDAY NIGHT AS TEMPERATURES AND THICKNESSES DROP NEAR CRITICAL
VALUES. OTHERWISE...PRECIP ALL RAIN OTHER PERIODS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE MAIN FOCUS IS COMPRISED OF PRECIP CHANCES AT THE BEGINNING OF
THE EXTENDED PERIOD IN REGARD TO A STATIONARY FRONT OVER THE
TENNESSEE VALLEY...AND THE NEXT UPPER LEVEL LOW AT THE END OF THE
PERIOD.
THE EXTENDED STARTS OUT WITH A COLD FRONT LINGERING AROUND THE OHIO
RIVER ON MONDAY...AND MODELS SEEM TO BE IN AGREEMENT WITH THIS.
SO...WILL STAY WITH INITIALIZATION NUMBERS...WHICH PUT THE HIGHEST
POPS ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA THROUGH MONDAY
NIGHT.
THE NEXT PART OF THE EXTENDED FORECAST BECOMES MORE NEBULOUS. GFS
AND EURO CONTINUE TO BE IN DISAGREEMENT IN REGARD TO APPROACHING
UPPER LEVEL LOW. THE AGREEMENT IN TIMING BETWEEN THE 2 MODELS SEEMS
EVEN WORSE THAN YESTERDAY WITH THE GFS SPEEDING THE TROUGH UP EVEN
MORE. THE GFS IS SHOWING THE DEEP UPPER LOW OVER THE UPPER MIDWEST
BY TUESDAY AFTERNOON...WHILE THE EURO HAS IT FORMING INTO A CUT-OFF
LOW OVER THE SOUTHERN PLAINS. BY THE TIME THE EURO HAS THE LOW IN
THE MIDWEST ON WEDNESDAY AFTERNOON THE GFS ALREADY HAS IT OVER LAKE
ONTARIO. IN ADDITION...THE GFS IS SHOWING A DEEP CUT-OFF LOW OVER
THE LOWER MISSISSIPPI VALLEY BEHIND THE INITIAL WAVE...WHEREAS THE
EURO ONLY HINTS AT IT.
OF THE 2 MODELS...THE INITIALIZATION NUMBERS CONTINUE TO FAVOR THE
DRIER GFS. AGAIN...THERE IS STILL NOT CONSISTENT ENOUGH TRENDING TO
DEVIATE FROM THE INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 02/15Z IND TAF UPDATE/...
NO CHANGES NECESSARY FOR THE MOMENT. POSTFRONTAL AREA OF IFR
CEILINGS/MVFR VISIBILITIES WILL REQUIRE MONITORING...ESPECIALLY AT
LAF/HUF AND PERHAPS AT IND. RUC SOUNDING AT LAF BEGINNING TO LOOK
TROUBLESOME FOR THE NEXT FEW HOURS...ALTHOUGH STILL EXPECTING TO
ERODE ENOUGH TO AVOID IMPACTING TAF SITES. PREVIOUS DISCUSSION
FOLLOWS.
MID AND HIGH LEVEL CLOUDS WILL AFFECT TAF SITES THIS MORNING IN
WAKE OF A WEAK FRONTAL BOUNDARY...BUT CONDITIONS SHOULD STILL
STAY AT VFR CATEGORY. MUCH DRIER AIR WILL QUICKLY FILTER INTO TAF
SITES BY EARLY AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE
MIDWEST. SO...VFR CONDITIONS WILL PREVAIL FOR ENTIRE TAF PERIOD.
MID LEVEL CLOUDS WILL INCREASE EARLY TOMORROW MORNING AHEAD OF
THE NEXT UPPER LEVEL DISTURBANCE...BUT AGAIN VFR CONDITIONS ARE
EXPECTED. WINDS WILL SLOWLY VEER TO THE EAST/SOUTHEAST THROUGH THE
COURSE OF THIS AFTERNOON BUT WILL REMAIN LIGHT AT 4 TO 8 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/SMF
SHORT TERM...JH
LONG TERM....TDUD
AVIATION...TDUD/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
928 AM EST FRI DEC 2 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A WEAKENING COLD FRONT FROM NORTHERN INDIANA TO SOUTHEAST MISSOURI
WILL MOVE INTO OUR REGION LATER TODAY AND GRADUALLY DISSIPATE. AN
AREA OF HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE OUR WEATHER
TONIGHT AND SATURDAY. RAIN WILL SPREAD INTO OUR REGION LATE
SATURDAY NIGHT AND SUNDAY AS ANOTHER AND STRONGER COLD FRONT MOVES
OUR WAY. SEVERAL MODELS STALL THIS FRONT FROM THE LOWER MISSISSIPPI
VALLEY TO OHIO EARLY NEXT WEEK...KEEPING SOUTHERN SECTIONS VERY
WET. FARTHER NORTH MIXED PRECIP WILL BE THE RULE AS COLDER AIR
SPREADS INTO OUR REGION. FINALLY DRY AND COLD WEATHER WILL BE THE
RULE AFTER THE MIDDLE OF NEXT WEEK AS THE FRONT TO OUR EAST MOVES
EAST AND HIGH PRESSURE OVER THE ROCKIES BUILDS OUR WAY.
&&
.NEAR TERM /TODAY/...
AN EXTENSIVE AREA OF MID CLOUDS ACROSS NORTHERN INDIANA AND CENTRAL
ILLINOIS WAS SPREADING INTO OUR REGION THIS MORNING. EARLY ON EXPECT
THE NORTHWEST HALF OF OUR REGION TO BE MOSTLY CLOUDY. BUT BY MIDDAY
MODELS SHOW QUITE A BIT OF DRYING AS HIGH PRESSURE BUILDS INTO THE
GREAT LAKES AND DOWNWARD VERTICAL VELOCITIES OCCUR. MAIN FOCUS WILL
BE HOW LONG CLOUDS REMAIN. SLOWED DOWN CLEARING JUST A LITTLE.
OTHERWISE...WENT CLOSE TO A MODEL BLEND.
VISIBLE SATELLITE YESTERDAY INDICATED A LITTLE REMAINING SNOW COVER
ACROSS PARTS OF OUR FAR NORTH AND NORTHEAST WHICH MAY HOLD
TEMPERATURES DOWN THERE JUST A LITTLE. OTHERWISE...WENT NEAR A
MAV/MET BLEND ON TEMPERATURES MOST OTHER AREAS TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
MODELS ARE IN GOOD AGREEMENT THIS PERIOD SO USED A BLEND WITH ONLY
MINOR ADJUSTMENTS.
SATURDAY WILL BE MILD AND DRY AS A SOUTHERLY FLOW INCREASES ACROSS
OUR REGION AS THE RESULT OF HIGH PRESSURE OVER THE EASTERN U.S. AND
LOW PRESSURE MOVING FROM THE CENTRAL PLAINS TOWARDS THE GREAT
LAKES.
MODELS THIS RUN ARE A TAD SLOWER IN BEGINNING PRECIP MAINLY LATE
SATURDAY NIGHT AND MAINTAINING IT A LITTLE FARTHER NORTH SUNDAY AND
SUNDAY NIGHT. A COLD FRONT WILL MOVE EAST ACROSS OUR REGION SUNDAY
AND STALL NEAR OR JUST A LITTLE SOUTH OF THE OHIO RIVER SUNDAY
NIGHT. IN MOST CASES...WENT CLOSE TO A MOS BLEND ON TEMPERATURES
AND POPS.
A PERIOD OF MIXED PRECIP POSSIBLE ACROSS OUR NORTH MAINLY LATE
SUNDAY NIGHT AS TEMPERATURES AND THICKNESSES DROP NEAR CRITICAL
VALUES. OTHERWISE...PRECIP ALL RAIN OTHER PERIODS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE MAIN FOCUS IS COMPRISED OF PRECIP CHANCES AT THE BEGINNING OF
THE EXTENDED PERIOD IN REGARD TO A STATIONARY FRONT OVER THE
TENNESSEE VALLEY...AND THE NEXT UPPER LEVEL LOW AT THE END OF THE
PERIOD.
THE EXTENDED STARTS OUT WITH A COLD FRONT LINGERING AROUND THE OHIO
RIVER ON MONDAY...AND MODELS SEEM TO BE IN AGREEMENT WITH THIS.
SO...WILL STAY WITH INITIALIZATION NUMBERS...WHICH PUT THE HIGHEST
POPS ACROSS THE SOUTHERN PORTIONS OF CENTRAL INDIANA THROUGH MONDAY
NIGHT.
THE NEXT PART OF THE EXTENDED FORECAST BECOMES MORE NEBULOUS. GFS
AND EURO CONTINUE TO BE IN DISAGREEMENT IN REGARD TO APPROACHING
UPPER LEVEL LOW. THE AGREEMENT IN TIMING BETWEEN THE 2 MODELS SEEMS
EVEN WORSE THAN YESTERDAY WITH THE GFS SPEEDING THE TROUGH UP EVEN
MORE. THE GFS IS SHOWING THE DEEP UPPER LOW OVER THE UPPER MIDWEST
BY TUESDAY AFTERNOON...WHILE THE EURO HAS IT FORMING INTO A CUT-OFF
LOW OVER THE SOUTHERN PLAINS. BY THE TIME THE EURO HAS THE LOW IN
THE MIDWEST ON WEDNESDAY AFTERNOON THE GFS ALREADY HAS IT OVER LAKE
ONTARIO. IN ADDITION...THE GFS IS SHOWING A DEEP CUT-OFF LOW OVER
THE LOWER MISSISSIPPI VALLEY BEHIND THE INITIAL WAVE...WHEREAS THE
EURO ONLY HINTS AT IT.
OF THE 2 MODELS...THE INITIALIZATION NUMBERS CONTINUE TO FAVOR THE
DRIER GFS. AGAIN...THERE IS STILL NOT CONSISTENT ENOUGH TRENDING TO
DEVIATE FROM THE INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 02/15Z IND TAF UPDATE/...
NO CHANGES NECESSARY FOR THE MOMENT. POSTFRONTAL AREA OF IFR
CEILINGS/MVFR VISIBILITIES WILL REQUIRE MONITORING...ESPECIALLY AT
LAF/HUF AND PERHAPS AT IND. RUC SOUNDING AT LAF BEGINNING TO LOOK
TROUBLESOME FOR THE NEXT FEW HOURS...ALTHOUGH STILL EXPECTING TO
ERODE ENOUGH TO AVOID IMPACTING TAF SITES. PREVIOUS DISCUSSION
FOLLOWS.
MID AND HIGH LEVEL CLOUDS WILL AFFECT TAF SITES THIS MORNING IN
WAKE OF A WEAK FRONTAL BOUNDARY...BUT CONDITIONS SHOULD STILL
STAY AT VFR CATEGORY. MUCH DRIER AIR WILL QUICKLY FILTER INTO TAF
SITES BY EARLY AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE
MIDWEST. SO...VFR CONDITIONS WILL PREVAIL FOR ENTIRE TAF PERIOD.
MID LEVEL CLOUDS WILL INCREASE EARLY TOMORROW MORNING AHEAD OF
THE NEXT UPPER LEVEL DISTURBANCE...BUT AGAIN VFR CONDITIONS ARE
EXPECTED. WINDS WILL SLOWLY VEER TO THE EAST/SOUTHEAST THROUGH THE
COURSE OF THIS AFTERNOON BUT WILL REMAIN LIGHT AT 4 TO 8 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM....TDUD
AVIATION...TDUD/NIELD
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
729 AM EST FRI DEC 2 2011
.SYNOPSIS...
A QUICK-MOVING COLD FRONT WILL SWEEP THROUGH THE REGION TODAY
WITH SCATTERED TO NUMEROUS SNOW SHOWERS AND POSSIBLE SNOW
SQUALLS. THIS FRONT WILL BRING A POTENTIAL LIGHT SNOW
ACCUMULATION ACROSS NORTHERN NEW YORK LATE THIS MORNING INTO
EARLY THIS AFTERNOON...AND ACROSS NORTHERN VERMONT DURING THE
EARLY TO MID AFTERNOON HOURS. SKIES CLEAR TONIGHT WITH HIGH
PRESSURE BUILDING ACROSS THE NORTH COUNTRY. THIS WILL SET UP A
CHILLY NIGHT WITH LOWS IN THE TEENS TO LOWER 20S. HIGH PRESSURE
AND DRY WEATHER CONTINUE FOR THE WEEKEND WITH SEASONABLY COOL
TEMPERATURES ON SATURDAY MODERATING TO ABOVE NORMAL BY SUNDAY ON
GUSTY SOUTH WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 312 AM EST FRIDAY...MID-LEVEL CLOUDS ARE GRADUALLY
OVERSPREADING THE NORTH COUNTRY EARLY THIS MORNING IN ASSOCIATION
WITH UPSTREAM TROUGH AND COLD FRONT ACROSS SERN ONTARIO INTO
LOWER MICHIGAN. UPR TROUGH IS INITIALLY POSITIVE TILT...BUT
BECOMES MORE NEUTRAL TODAY AND SWINGS RAPIDLY THRU THE NORTH
COUNTRY AS A RATHER VIGOROUS WAVE THIS AFTN. NOT MUCH CHANGE FROM
PREVIOUS FCST...WITH BEST THREAT FOR SNOW SHOWERS FROM 14-17Z IN
THE SAINT LAWRENCE VALLEY...16-19Z IN THE ADIRONDACKS...17-21Z IN
THE CHAMPLAIN VALLEY...AND 18-22Z ACROSS THE REST OF VERMONT. THE
SNOW SHOWERS MAY BEGIN AS SOME LIGHT RAIN/SNOW IN THE VALLEY
LOCATIONS WITH SURFACE TEMPERATURES CLOSE TO 40 DEGREES...BUT
SHOULD CHANGE OVER TO SNOW AS THE PRECIPITATION CONTINUES TO
FALL. NARROW AREAS OF 35-40 DBZ MODEL REFLECTIVITY INDICATED IN
3-KM HRRR AND 4-KM LOCAL WRF RUN ASSOCIATED WITH POSSIBLE SNOW
SQUALL ACTIVITY. NOT MUCH SFC BASED INSTABILITY...BUT STEEP LAPSE
RATES AND STRONG DEEP- LAYER VORTICITY ADVECTION COULD BE
SUFFICIENT TO ORGANIZE BAND OF SNOW SQUALLS ACROSS NRN NY INTO
NRN VT TODAY. GREATEST COVERAGE OF SNOW SHOWERS WILL LIKELY BE
ACROSS NORTHERN NEW YORK AND INTO THE HIGHER ELEVATIONS OF
NORTHERN VERMONT. ACCUMULATIONS WILL BE LIGHT...GENERALLY LESS
THAN AN INCH...ALTHOUGH SOME OF THE HIGHER ELEVATIONS OF THE
GREEN MOUNTAINS COULD SEE UP TO 2 INCHES. THIS MAY ACCUMULATE
QUICKLY IN ANY SQUALLS...AND RESULT IN SLOW TRAVEL CONDITIONS FOR
A BRIEF TIME WITH LOW VSBY. HAVE HIGHLIGHTED THREAT IN THE
HAZARDOUS WEATHER OUTLOOK. HIGH TEMPERATURES WILL BE REACHED
BEFORE THE ONSET OF PRECIPITATION...GENERALLY MID TO UPPER
30S...WITH SOME LOW 40S IN THE CHAMPLAIN VALLEY. TEMPERATURES
WILL FALL QUICKLY WITH ONSET OF PCPN THROUGH THE 30S...AND INTO
THE 20S AFTER THE PASSAGE OF THE FRONT. THERE COULD ALSO BE A
PERIOD OF GUSTY NORTHWEST WINDS AFTER THE PASSAGE OF THE COLD
FRONT LATE FRIDAY AFTERNOON AND EVENING WITH SOME GUSTS 15-30
MPH.
CLEARING SKIES AND LIGHTER WINDS TONIGHT WITH STRONG SFC
ANTICYCLONE CRESTING OVER THE NORTH COUNTRY AT 12Z SATURDAY. LOW
TEMPERATURES GENERALLY IN THE TEENS...EXCEPT LOW 20S IN THE
CHAMPLAIN VALLEY. COULD SEE AN ISOLD READING IN THE UPR SINGLE
DIGITS IN THE NRN ADIRONDACKS...INCLUDING AT KSLK.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 312 AM EST FRIDAY...RIDGE OF HIGH PRESSURE IN PLACE FOR
SATURDAY...AND FEATURE WILL TRANSLATE SLOWLY EASTWARD TO THE GULF
OF MAINE LATE IN THE DAY. THIS WILL ALLOW AIR MASS TO MODERATE
WITH DEVELOPING SOUTH WINDS 5-10 MPH BY AFTN. LOOKING AT DRY
WEATHER...MOSTLY SUNNY SKIES AND SEASONABLE HIGH TEMPS FOR EARLY
DECEMBER IN THE MID-UPR 30S.
SOUTH TO SOUTHWEST GRADIENT FLOW PICKS UP SATURDAY NIGHT AND
ESPECIALLY ON SUNDAY. THESE WINDS AND PASSING MID-UPR CLOUDS WILL
KEEP LOW TEMPERATURES A BIT MILDER FOR SATURDAY NIGHT...AND THEN
TEMPS REBOUNDING INTO THE UPR 40S FOR SUNDAY. SOUTH WINDS COULD
BE RATHER GUSTY SUNDAY...GENERALLY 15-25 MPH WITH GUSTS TO 35 MPH
POSSIBLE PER 00Z NAM MODEL SOUNDINGS. A COLD FRONT WILL BE MOVING
EWD THRU THE GREAT LAKES REGION LATE IN THE DAY. AT THIS TIME
HELD OFF ON ANY PRECIPITATION ASSOCIATED WITH THIS
FEATURE...THOUGH CLOUDS WILL BE ON THE INCREASE LATE SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 345 AM EST FRIDAY...LOW PRESSURE SITUATED TO OUR WEST ON
SUNDAY EVENING WILL LIFT NORTH INTO CANADA OVERNIGHT...WEAK COLD
FRONT ASSOCIATED WITH THIS LOW WILL CROSS OUR REGION THOUGH
LIMITED MOISTURE ASSOCIATED WITH THIS FEATURE SO WILL ONLY
MENTION CHANCE POPS AT THIS TIME. AFOREMENTIONED FRONT WILL STALL
OUT TO SOUTHEAST AND SEVERAL WAVES OF MOISTURE WILL RIDE ALONG
THIS FRONT BRINGING MORE PRECIPITATION TO THE REGION. THE GFS AND
ECMWF BOTH SHOW THIS SCENARIO...BUT THE GFS SHOWS IT ENDING
SOONER THAN THE ECMWF. THE ECMWF HANGS ONTO THE PRECIP ALL THE
WAY THROUGH THURSDAY AND THE GFS ENDS THE PRECIP ON TUESDAY
NIGHT. AT THIS TIME HAVE MENTIONED HIGHEST POPS FOR MONDAY NIGHT.
TEMPERATURES WILL CONTINUE TO RUN WARMER THAN NORMAL THROUGH THE
PERIOD. RIGHT NOW LOOKS LIKE THE MAJORITY OF THE PRECIP WE GET
NEXT WEEK WILL BE RAIN WITH A POSSIBLE CHANGEOVER TO SNOW AT THE
END OF THE EVENT.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
THROUGH 12Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH 15Z
FRIDAY...AS A RIDGE OF HIGH PRESSURE SLOWLY MOVES EAST OF THE
REGION...WITH SOME AREAS OF MVFR CEILINGS ACROSS NORTHERN NEW
YORK. AN UPPER TROUGH WILL APPROACH THE REGION DURING THE DAY
TODAY. EXPECTING AREAS OF IFR/MVFR IN LIGHT SNOW DEVELOPING
ACROSS NORTHERN NEW YORK BETWEEN 16Z-18Z FRIDAY...AND THEN MOVING
INTO VERMONT BETWEEN 19Z-21Z FRIDAY. WINDS WILL BE GUSTY WITH
POSSIBLE SNOW SQUALLS DURING THIS TIME PERIOD ALSO. CONDITIONS
WILL CLEAR UP BY ABOUT 00Z AND VFR RETURNS...CLEAR SKIES AND
LIGHT WINDS ARE EXPECTED OVERNIGHT. .
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...MAINLY VFR CONDITIONS
EXPECTED THROUGH THE PERIOD...AS A RIDGE OF HIGH PRESSURE WILL BE
OVER THE REGION. SOME GUSTY SOUTHERLY WINDS ARE POSSIBLE ON
SUNDAY DURING THE DAYTIME HOURS. AREAS OF MVFR/IFR CONDITIONS
POSSIBLE IN RAIN AND SNOW SHOWERS MONDAY AND TUESDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...NEILES
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
545 AM CST FRI DEC 2 2011
.UPDATE...
SEE AVIATION DISCUSSION BELOW.
&&
.AVIATION...
AVIATION CONDITIONS WILL REMAIN PROBLEMATIC THROUGH THE PERIOD
ACROSS WEST CENTRAL TEXAS TERMINALS. COLD FRONT HAS CLEARED ALL OF
THE SITES EARLY THIS MORNING...WITH MVFR CIGS AND PATCHY AREAS OF
LIGHT RAIN BEHIND THE FRONT. THESE CONDITIONS SHOULD PERSIST FOR
MUCH OF THE MORNING HOURS...AND PROBABLY WELL INTO THE AFTERNOON.
AS A STRONG LOW LEVEL JET BRINGS MOISTURE UP AND OVER THE BOUNDARY
LATE THIS AFTERNOON AND INTO TONIGHT...CONDITIONS SHOULD QUICKLY
DETERIORATE ACROSS ALL SITES...PERHAPS EVEN DOWN INTO THE LIFR
RANGE. HOW QUICKLY THIS HAPPENS...AND WHEN IT STARTS REMAINS A BIG
QUESTION THOUGH. WITH THIS MUCH WARM ADVECTION OVER THE
FRONT...THE FRONT WILL EVENTUALLY BEGIN TO LIFT BACK NORTH AS A
WARM FRONT. AGAIN...WHEN THIS STARTS TO OCCUR IS VERY
UNCERTAIN...BUT ANTICIPATING A RAPID NORTHWARD MOVEMENT OF THE
FRONT BACK TO NEAR THE INTERSTATE 20 CORRIDOR BY MORNING.
CONDITIONS NORTH OF THE FRONT WILL CONTINUE TO BE A CONCERN..BUT
CONDITIONS SOUTH OF THE FRONT MAY ACTUALLY IMPROVE BY SUNRISE
SATURDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 345 AM CST FRI DEC 2 2011/
SHORT TERM...
COMPLICATED FORECAST CONTINUES FOR WEST CENTRAL TEXAS. STRONG COLD
FRONT HAS CLEARED ALL BUT THE EXTREME SOUTHEAST PORTIONS OF THE AREA
AS OF 09Z...WITH ONLY JUNCTION AND MASON HAVING NOT SEEN THE FRONTAL
PASSAGE SO FAR. THE NAM AND THE RUC HAVE BOTH HANDLED THE MOVEMENT
OF THE FRONT IN THE SHORT TERM FAIRLY WELL...AND THEY BOTH PUSH THE
FRONT THROUGH THE REMAINDER OF THE AREA BY 12Z...AND THEN STALL IT
JUST TO THE SOUTH. PRESSURE RISES BEHIND THE FRONT HAVE SLOWLY
DECREASED...BUT THE GUSTY NORTH WINDS CONTINUE. GIVEN THESE
WINDS...AND THE DENSITY OF THE COLDER AIR MASS...WILL ASSUME THAT
THE MODELS ARE CORRECT IN PUSHING THE FRONT THROUGH THE REST OF THE
AREA BEFORE PULLING UP STATIONARY.
MEANWHILE...POTENT UPPER LEVEL STORM SYSTEM APPROACHING FROM THE
SOUTHWEST US WILL LEAD TO INCREASING WARM ADVECTION UP AND OVER THE
FRONTAL BOUNDARY...REACHING 40 KTS BY 00Z AND OVER 50 KTS BY
MIDNIGHT. DRIZZLE AND LIGHT RAIN HAS ALREADY BEEN DEVELOPING...AND
THIS WILL CONTINUE AS THIS ISENTROPIC LIFT STRENGTHENS. HAVE
INCREASED POPS FOR TODAY AND TONIGHT. THIS WARM AND MOIST AIR MASS
WILL RIDE UP AND OVER THE COLDER AIR AT THE SURFACE...LEAVING THE
BOUNDARY TO THE SOUTH. HOWEVER...AS THE WARM ADVECTION
INTENSIFIES...THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTHWARD THIS
EVENING...ALTHOUGH HOW FAR NORTH IS STILL A BIG QUESTION. IN ANY
CASE...DONT EXPECT TEMPERATURES TO DROP MUCH TONIGHT...AND ACROSS
MOST OF THE AREA..TEMPERATURES WILL ACTUALLY CLIMB SUBSTANTIALLY
OVERNIGHT.
07
LONG TERM...
A COLD AND UNSETTLED PATTERN WILL CONTINUE THROUGH MUCH OF THE
EXTENDED FORECAST. A MODEST WARM UP CAN BE EXPECTED ON SATURDAY AS
WARM FRONT LIFTS NORTH THROUGH WEST CENTRAL TEXAS. HIGH TEMPERATURES
WILL RANGE FROM NEAR 60 NORTH...TO NEAR 70 SOUTH. IN THE
MEANTIME...A LARGE UPPER LEVEL TROUGH WILL BE LOCATED ACROSS THE
DESERT SOUTHWEST...AND AN ARCTIC COLD FRONT WILL BE LOCATED OVER
THE SOUTHERN PLAINS. AN UPPER LEVEL SHORTWAVE TROUGH WILL TRACK
ACROSS THE NORTHERN PLAINS SATURDAY HELPING TO SEND THIS COLD
FRONT THROUGH WEST CENTRAL TEXAS SATURDAY NIGHT. SHOWERS WILL BE
POSSIBLE ALONG AND AHEAD OF THE BOUNDARY...AND THIS IS REFLECTED
IN THE CURRENT GRIDS. COLD AIR ADVECTION...CLOUD COVER AND LIGHT
RAIN WILL HELP TO KEEP TEMPERATURES DOWN ON SUNDAY. DROPPED HIGH
TEMPERATURES A FEW DEGREES...GENERALLY IN THE UPPER 30S TO MID
40S...AND THESE MAY NEED TO BE LOWERED ON FUTURE SHIFTS.
ON SUNDAY NIGHT...AFOREMENTIONED UPPER LEVEL TROUGH REMAINS ACROSS
THE DESERT SOUTHWEST...WHILE ANOTHER UPPER LEVEL SHORTWAVE TROUGH
SKIRTS ACROSS THE CENTRAL PLAINS. THIS WILL HELP TO SEND A
REINFORCING SHOT OF COLDER AIR INTO THE AREA...WITH NORTH WINDS
INCREASING MONDAY MORNING AND COLD AIR FILTERING IN. IN
ADDITION...UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE ACROSS
THE AREA IN ADVANCE OF THE MAIN UPPER LEVEL TROUGH LOCATED OVER
THE SOUTHWEST STATES. THIS WILL LIKELY PRODUCE LIGHT PRECIPITATION
ACROSS THE AREA SUNDAY NIGHT AND MONDAY. THE MAIN QUESTION THEN
BECOMES...WHAT TYPE OF PRECIPITATION. MODEL SOUNDINGS AND
700MB/850MB TEMPERATURES ARE INDICATING A RAIN/SNOW MIX ACROSS THE
NORTHERN HALF OF THE AREA EARLY MONDAY...THEN TRANSITIONING TO
RAIN/SNOW ACROSS MUCH OF THE AREA BY LATE MONDAY...AND MOSTLY SNOW
ACROSS THE NORTHERN COUNTIES. THIS SCENARIO IS REFLECTED IN THE
CURRENT FORECAST PACKAGE. AT THIS TIME ANY ACCUMULATIONS SHOULD BE
LIGHT...BUT A LOT OF UNCERTAINTY REMAINS IN THE AMOUNT OF
PRECIPITATION AND THE PRECIPITATION TYPE SUNDAY AND MONDAY. HIGH
TEMPERATURES ON MONDAY WILL BE WELL BELOW NORMAL...RANGING FROM
THE MID 30S NORTH...TO NEAR 40 SOUTH. GIVEN THE FRIGID AIRMASS AND
EXPECTED CLOUD COVER...THE CURRENT HIGH TEMPERATURES IN THE
FORECAST MAY BE A BIT HIGH.
MODELS CONTINUE TO HANG THE UPPER LEVEL TROUGH WEST OF THE
AREA...BEFORE FINALLY SWINGING IT THROUGH LATE TUESDAY. INTRODUCED
SLIGHT CHANCE POPS ACROSS THE AREA MONDAY NIGHT...BEFORE CONDITIONS
IMPROVE TUESDAY MORNING. ANY PRECIPITATION THAT DOES OCCUR WILL
LIKELY FALL AS LIGHT SNOW. ANOTHER VERY COLD DAY IS LIKELY ON
TUESDAY...AND DROPPED TEMPERATURES A FEW DEGREES. A SLOW WARM UP
WILL ENSUE BY THE MIDDLE OF NEXT WEEK...WITH CLOSER TO NORMAL
TEMPERATURES RETURNING BY THURSDAY.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 38 38 63 32 39 / 60 60 60 20 30
SAN ANGELO 44 44 66 35 42 / 50 60 50 20 20
JUNCTION 55 55 69 40 44 / 40 60 40 50 40
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
550 AM CST FRI DEC 2 2011
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
347 AM CST FRI DEC 2 2011
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR AFTER MIDNIGHT TONIGHT
THROUGH SUNDAY MORNING AND POSSIBLE HAZARDS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH OVER SOUTHWEST CANADA...RIDGING OUT
AHEAD OVER THE NORTHERN PLAINS INTO MANITOBA...AND TROUGHING OVER
THE LAKE MICHIGAN AREA. ALSO OF NOTE IS IN THE SOUTHERN STREAM OF AN
UPPER LOW OVER THE DESERT SOUTHWEST. THE FORECAST AREA LIES IN
SUBSIDENCE IMMEDIATELY BEHIND THE LAKE MICHIGAN TROUGH...PROMOTING
HIGH PRESSURE AT THE SURFACE. IN FACT...THE SUBSIDENCE AND DRYING
HAS BEEN ENOUGH TO RESULT IN CLEAR SKIES OVER THE AREA. UPSTREAM 00Z
SOUNDINGS FROM INL AND ABR REFLECT THE DRYING WELL WITH PRECIPITABLE
WATER VALUES UNDER TWO TENTHS OF AN INCH. THE COMBINATION OF THE
CLEAR SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES TO DROP INTO
THE TEENS TO MID 20S. TO THE NORTHWEST...A STREAM OF UPPER LEVEL
MOISTURE CAN BE SEEN ACROSS THE NORTHERN PLAINS INTO SOUTH CENTRAL
CANADA ON WATER VAPOR....AHEAD OF THE UPPER TROUGH THERE...WHICH IS
MANIFESTING ITSELF INTO A LARGE ALTOSTRATUS AND CIRROSTRATUS DECK.
TO THE SOUTHWEST...850MB WINDS HAVE BEEN INCREASING OUT OF THE SOUTH
OVER TEXAS DOWNSTREAM OF THE UPPER LOW...BRINGING GULF OF MEXICO
MOISTURE NORTHWARD TOWARDS OKLAHOMA AS SEEN IN GOES PRECIPITABLE
WATER PLOTS.
TODAY AND TONIGHT...A WARM ADVECTION PATTERN LOOKS TO DEVELOP OVER
THE AREA IN RESPONSE TO THE UPPER TROUGH OVER SOUTHWEST CANADA
SPLITTING INTO TWO...WHERE ONE PIECE MARCHES EAST INTO NORTHWEST
ONTARIO AND NORTH DAKOTA BY 12Z SATURDAY. THE OTHER PIECE DIGS SOUTH
TOWARDS THE LAS VEGAS AREA...CAUSING THE CURRENT UPPER LOW IN
ARIZONA TO GET PUSHED EAST INTO NEW MEXICO. CONDITIONS WILL REMAIN
DRY TODAY GIVEN PLENTIFUL DRY AIR AROUND AS SEEN FROM 00Z SOUNDINGS.
IN FACT...SKIES SHOULD STAY CLEAR TO 00Z. WINDS ARE LIKELY TO
INCREASE...THOUGH...AS THE PRESSURE GRADIENT TIGHTENS UP BEHIND THE
DEPARTING SURFACE RIDGE. TONIGHT IS A DIFFERENT STORY. THE SOUTHERLY
RETURN FLOW SEEN OCCURRING OVER TEXAS NOW IS FORECAST TO EXPAND AND
INTENSIFY TONIGHT...RUNNING FROM DEEP SOUTH TEXAS INTO KANSAS...THEN
NORTHEAST INTO THE FORECAST AREA BY 06Z. 850MB WINDS IN THIS ZONE
ARE PROGGED BETWEEN 40-50 KT. PRECIPITABLE WATER VALUES RESPOND BY
JUMPING FROM AROUND 0.25 INCH AT 00Z TO 0.5-0.8 INCHES AT 12Z...
HIGHEST IN THE SOUTHEASTERN PORTION OF THE FORECAST AREA. 0.75
INCHES REPRESENTS 200 PERCENT OF NORMAL. AS THE DEEPER MOISTURE
ISENTROPICALLY LIFTS INTO THE COLDER AIRMASS OVER THE AREA...
ANTICIPATING PRECIPITATION TO BREAK OUT. MODELS ARE IN VERY GOOD
AGREEMENT ON THIS OCCURRING...WITH THE HIGHEST CONSENSUS OVER THE
SOUTHEASTERN TWO-THIRDS OF THE AREA. PLACED 80-100 PERCENT CHANCES
IN THE SOUTHEAST HALF...THEN TRENDED DRIER HEADING UP TO THE
NORTHWEST INTO LOWER PRECIPITABLE WATER VALUES. P-TYPE A LITTLE
TRICKY AS A SURGE OF WARMER AIR ALSO ACCOMPANIES THE MOISTURE SURGE.
850MB TEMPS ARE PROGGED TO WARM TO 0-2C OVER THE SAME AREA WITH THE
HIGHEST PRECIPITABLE WATER. SHOULD BE MOSTLY A RAIN/SNOW SCENARIO AS
SURFACE TEMPERATURES WARM OVERNIGHT...BUT COULD SEE FREEZING RAIN
TOO IF SURFACE TEMPERATURES HAVE NOT WARMED ABOVE FREEZING OR FROM
NOT ENOUGH ICE PRESENT ALOFT YET. ANY SNOW/ICE ACCUMULATION LOOKS
MINIMAL TONIGHT. HAVE NOT INCLUDED ANY FREEZING RAIN/DRIZZLE BECAUSE
UNCERTAINTY IS JUST TOO HIGH.
SATURDAY THROUGH SUNDAY...MODELS ARE ALL IN VERY GOOD AGREEMENT
KICKING OUT THE UPPER LOW FROM NEW MEXICO AT 12Z SATURDAY NORTHEAST
AS A SHEARING OUT SHORTWAVE. IN ADDITION...THE SHORTWAVE SHOULD GET
ACCELERATED NORTHEAST OVERNIGHT TONIGHT INTO SUNDAY IN RESPONSE TO
MORE TROUGHING DROPPING SOUTH INTO THE NORTHERN PLAINS. THERE ARE
SOME SLIGHT DIFFERENCES WITH RESPECT TO THE ASSOCIATED SURFACE LOW
WITH THE SHORTWAVE...WHICH HAS IMPLICATIONS ON THE TRACK AND
INTENSITY OF THE DEFORMATION PRECIPITATION ON THE NORTH SIDE OF THE
LOW. THE 02.00Z GFS IS THE WEAKEST WITH THE LOW AND FURTHEST
SOUTHEAST...HAVING IT TRACK ACROSS NORTHEAST ILLINOIS AT 12Z SUNDAY.
THE 02.00Z NAM IS FARTHEST NORTHWEST AND FASTEST...CROSSING THE BAY
OF GREEN BAY AT 12Z SUNDAY. THE 02.00Z ECMWF/UKMET IS A COMPROMISE.
FOR NOW FOLLOWED THE COMPROMISE APPROACH...SINCE THE GFS SOLUTION IS
PLAUSIBLE IF MORE CONVECTION CAN OCCUR THAN CURRENTLY PROGGED DOWN
OVER THE SOUTHERN PLAINS. ON THE FLIP SIDE...THERE HAS BEEN QUITE A
BIT OF CONSISTENCY WITH THE ECMWF AND NAM SOLUTIONS. SATURDAY
MORNING SHOULD BE A CONTINUATION OF PRECIPITATION FROM AFTER
MIDNIGHT TONIGHT...DUE TO PERSISTENT ISENTROPIC LIFT. PRECIPITATION
THEN LOOKS TO INTENSIFY IN THE AFTERNOON...PARTICULARLY OVER THE
NORTHWEST HALF OF THE FORECAST AREA...AS THE DEFORMATION AREA OF THE
SURFACE LOW APPROACHES. HEAVIEST PRECIPITATION STILL LOOKS TO OCCUR
SATURDAY EVENING WHEN STRONGEST LOW TO MID-LEVEL FRONTOGENESIS MOVES
ACROSS. IN FACT...CROSS-SECTIONS SHOW THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...SUGGESTING CONVECTIVE
ELEMENTS ARE POSSIBLE. AGAIN...THE HEAVIEST PRECIPITATION LOOKS TO
END UP OVER THE NORTHWEST HALF OF THE FORECAST AREA. WITH SNOW TO
WATER RATIOS LIKELY TO END UP SOMEWHERE AROUND 10 TO 1 AS AN AVERAGE
FOR SATURDAY AND SATURDAY NIGHT...COMBINED WITH QPF AMOUNTS AROUND
0.60 OF AN INCH...TOTAL SNOWFALL WOULD COME OUT TO AROUND 6 INCHES.
GIVEN THAT THE NORTHWEST HALF OF THE FORECAST AREA HAS NOT REALLY
SEEN ITS FIRST SIGNIFICANT SNOW...HAVE ISSUED A WINTER STORM WATCH
FOR THAT AREA. BIGGEST CONCERN OF THE WATCH IS SATURDAY AFTERNOON
AND EVENING...ESPECIALLY TOO WITH THE HOLIDAY SHOPPING/TRAVEL TAKING
PLACE. FOR THE SOUTHEAST END OF THE FORECAST AREA...MAJORITY OF THE
PRECIPITATION MAY FALL AS RAIN OR A RAIN/SNOW MIX AS A SURGE OF WARM
AIR COMES IN. NEW 02.06Z NAM SUGGESTS EVEN A WARMER SURGE. LA CROSSE
COUNTY KEPT OUT OF THE WATCH DUE TO RAIN MIX EXPECTED ON SATURDAY.
FOR BOTH SATURDAY AND SATURDAY NIGHT...INCREASED PRECIPITATION
CHANCES ANYWHERE FROM 10 TO 30 PERCENT GIVEN GOOD CONTINUITY AND
MODEL AGREEMENT. PRECIPITATION SHOULD DIMINISH PRETTY QUICK ON
SUNDAY...THOUGH DID KEEP SOME 20 PERCENT CHANCES GOING IN THE
AFTERNOON FOR CENTRAL WISCONSIN WITH LINGERING UPPER TROUGHING.
CERTAINLY WILL BE COOLER ON SUNDAY WITH SNOW COVER AND 850MB TEMPS
OF -6 TO -8C MOVING IN.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO THE TROUGHING COMING
INTO THE NORTHERN PLAINS ON SUNDAY. GOOD AGREEMENT ON THIS UPPER
TROUGH HEADING EAST INTO THE FORECAST AREA ON MONDAY. HOWEVER...ALL
OF THE BETTER FORCING/MOISTURE APPEAR TO HEAD TO THE NORTH OF THE
AREA. AS SUCH...HAVE CONTINUED A DRY SUNDAY NIGHT AND ONLY KEPT A 20
PERCENT CHANCE IN FOR TAYLOR/CLARK COUNTIES ON MONDAY. COULD SEE
CHANCES BEING COMPLETELY REMOVED FOR MONDAY IF TRENDS CONTINUE.
ALTHOUGH PRECIPITATION LOOKS LIMITED...THE COLD AIR WILL NOT BE.
850MB TEMPS ARE PROGGED TO FALL EVEN FURTHER...DROPPING TO AT LEAST
-8 TO -12C BY 00Z TUESDAY...IF NOT A LITTLE COOLER THAN THAT AS
NOTED BY THE 02.00Z GFS. WENT WITH A BLEND OF GUIDANCE FOR LOWS AND
HIGHS DURING THIS PERIOD...WHICH END UP 5 TO 10 DEGREES COLDER THAN
SATURDAY NIGHT AND SUNDAY.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
347 AM CST FRI DEC 2 2011
AFTER A BUSY EARLY PART TO THE WEEKEND FOR THE WEATHER...MUCH OF THE
EARLY AND MIDDLE PORTION OF NEXT WEEK LOOK QUIET AND COOL. 02.00Z
ECMWF/CANADIAN/GFS/GFS ENSEMBLES ARE IN GOOD AGREEMENT FOR MUCH OF
THE LONG TERM FORECAST INDICATING THE TROUGHING THAT WAS OVER THE
AREA MONDAY LINGERING INTO TUESDAY...THEN JUST GRADUAL DEEP
TROUGHING FORMING OVER MUCH OF CANADA INTO THE NORTHERN U.S. HEADING
INTO THURSDAY. THIS TYPE OF PATTERN SUGGESTS LITTLE MOISTURE TO WORK
WITH AND AS SUCH MODEL QPF FORECASTS ARE PRETTY MUCH NOTHING. NEXT
REAL CHANCE OF PRECIPITATION COMES MAYBE ON THURSDAY NIGHT WITH SOME
HINTS OF SHORTWAVE TROUGHING DIGGING INTO THE WESTERN U.S....
RESULTING IN A WARM ADVECTION PATTERN DOWNSTREAM. STILL...THE
PRECIPITATION CHANCE LOOKS PRETTY SMALL. THE BIG THING IS
TEMPERATURES. 850MB TEMPS ARE PROGGED TO DROP TO ONLY SLOWLY RECOVER
TO -6 TO -8C ON WEDNESDAY...THEN FALL BACK TO -12 TO -18C OR SO FOR
THURSDAY. THEREFORE...TEMPERATURES ARE FORECAST TO STAY BELOW
NORMAL. FOLLOWED A CONSENSUS OF GUIDANCE FOR TEMPERATURES. CANNOT
RULE A PERIOD OF SOME BELOW ZERO TEMPERATURES FOR LOWS TOO...
ESPECIALLY FOR SOME OF THE TYPICAL COLD SPOTS.
&&
.AVIATION...TODAY INTO SATURDAY
550 AM CST FRI DEC 2 2011
A RIDGE OF HIGH PRESSURE WILL DRIFT ACROSS ACROSS THE UPPER MIDWEST
TODAY INTO THIS EVENING...BRINGING GOOD VFR CONDITIONS TO THE TAF
SITES THRU MIDNIGHT TONIGHT. A COLD FRONT WILL BE MOVING ACROSS THE
NORTHERN PLAINS TONIGHT WHILE LOW PRESSURE DEVELOPS IN THE SOUTHERN
PLAINS. INCREASING LOW/MID LEVEL MOISTURE WILL QUICKLY SURGE NORTH
AHEAD OF THE LOW AND FRONT...WITH CIGS EXPECTED TO DEVELOP/LOWER
OVER THE TAF SITES LATE TONIGHT. MAIN QUESTION IS HOW QUICKLY WILL
CIGS LOWER INTO MVFR AND -SN OR -SN/-RA MOVE INTO THE TAF SITES LATE
TONIGHT/SAT MORNING. NO CLEAR MODEL SIGNAL ON THE TIMING. GIVEN THE
INITIAL DEEP/DRY AIRMASS OVER THE AREA JUST INTRODUCED VCSH AND
LOWERED CIGS INTO THE 3K-4K FT RANGE AT KRST/KLSE TAFS LATE TONIGHT
TOWARD THE END OF THE TAF PERIOD. CIGS/VSBYS WILL CONTINUE TO LOWER
SAT AS MOISTURE/LIFT CONTINUE TO INCREASE OVER THE AREA AHEAD OF THE
APPROACHING LOW...WITH IFR CONDITIONS EXPECTED BY SAT AFTERNOON.
AIRMASS WILL BE COLD ENOUGH FOR MAINLY SNOW AT KRST AND A SN/RA MIX
AT KLSE. ACCUMULATING SNOWS EXPECTED AT KRST/KLSE...ESPECIALLY BY
SAT AFTERNOON AND FOR SAT EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 AM CST FRI DEC 2 2011
WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR WIZ017-029-032>034.
MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR MNZ079-086>088-094-095.
IA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION...CORRECTION
NWS GRAND JUNCTION CO
308 PM MST FRI DEC 2 2011
CORRECTED SHORT TERM TIME PERIOD DESCRIPTOR
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
THE CLOSED LOW OVER AZ FINALLY BEGINNING TO OPEN UP AND IS EXPECTED
TO EJECT THROUGH NM AND THE 4 CORNERS TONIGHT AS THE NEXT TROUGH
DIVES DOWN TO REPLACE IT. MOISTURE HAS SPREAD ACROSS MUCH SE UT AND
WRN CO TODAY AND NICELY CAPTURED ON THE 300K POTENTIAL TEMP
SURFACE...WITH LIGHT SNOW REPORTED OVER HIGHER TERRAIN FROM MOUNT
WERNER ABOVE STEAMBOAT SPGS TO GRAND MESA TO THE SAN JUAN MTNS. SNOW
ALSO ALONG THE SRN BASE OF THE SAN JUANS FROM CORTEZ TO PAGOSA IN THE
UPSLOPE FLOW. RUC MODELS SHOWS A COUPLE WAVES OF ENERGY MOVING UP
FROM THE LOW...SO EXPECT SNOW INTENSITY TO VARY THROUGH THE NIGHT
IN SW CO. CURRENT WINTER HIGHLIGHTS FOR THE SAN JUAN/ABAJO/LA SAL
MTNS AND THE DURANGO-PAGOSA AREA LOOK ON TRACK.
THE SECOND SPLITTING TROUGH WAS DROPPING ACROSS ID AND DRIVEN BY A
120 KT UPPER JET OVER THE PAC NW. THIS TROUGH EXPECTED TO PUSH A COLD
FRONT INTO NE UT/NW CO TONIGHT AND THEN INTO SE UT/SW CO SAT AS IT
FORMS A SECOND CLOSED OVER AZ. RATHER NARROW BAND OF MOISTURE
ASSOCIATED WITH THE TROUGH MOVING INTO NW UT...BUT EXPECT SNOW
COVERAGE TO INCREASE OVER NE UT/NW CO TONIGHT AS THE FRONT
INTERACTS WITH THE MOISTURE IN PLACE AHEAD OF THE AZ LOW. THE FRONT
EXPECTED TO SLOW ACROSS THE N LATE TONIGHT...AND A PERIOD DECENT
NORTHEAST OROGRAPHIC WINDS COMBINED WITH COLD ADVECTION SHOULD BRING
3-6 INCHES OF SNOW TO THE ERN UINTA MTNS...ESPECIALLY THEIR NORTH
SLOPES. BUT...NORTHEAST WINDS NOT AS STRONG OR AS LONG IN DURATION
AS THE STORM WED NIGHT...SO REFRAINED FROM ANY HIGHLIGHT FOR THE ERN
UINTAS AT THIS TIME. A PERIOD OF GUSTY NE WINDS LIKELY ACROSS NW CO
SAT MORNING AS WELL...BUT AGAIN NOT NEARLY AS STRONG AS WHAT OCCURRED
THU MORNING.
BOTH NAM AND GFS INDICATE A WEAK 700 MB LOW FORMS OVER WRN CO
TONIGHT/SAT MORNING. BANKING ON ENHANCED LOW LEVEL CONVERGENCE
AND EVENTUAL FRONTAL PASSAGE TO ENHANCE SNOWFALL FROM GRAND MESA TO
THE WEST ELKS. WEST ELKS SHOULD ALSO BENEFIT FROM SOME MOIST
SOUTHERLY OROGRAPHIC FLOW TONIGHT...WHILE TRAILING NORTHERLY FLOW MAY
KEEP SOME LIGHT SNOW OVER GRAND MESA INTO SAT EVENING. AS SUCH...
ELECTED TO INCLUDE THE GRAND MESA AND WEST ELKS /ZONES 9 AND 12/ IN A
LOW-END ADVISORY TONIGHT INTO SAT EVENING FOR 4 TO 9 INCHES OF
SNOW. THE 700 MB LOW SHOULD ALSO BRING SNOW TO MANY CENTRAL VALLEYS
BUT WITH LITTLE ACCUMS EXPECTED.
SNOW DIMINISHES SAT NIGHT WITH CLEARING FROM THE NW. ERN UT/WRN CO
SHOULD BE IN BETWEEN SYSTEMS SUNDAY AS MODELS SHOW YET A THIRD
SPLITTING TROUGH APPROACHING FROM THE N LATE IN THE WEEKEND. WILL
TREND THE CHANCE OF PRECIP UP AGAIN ACROSS THE NORTHERN MTNS SUNDAY
AFTERNOON AS A RESULT.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE EARLY PART OF THE LONG TERM IS A CONTINUATION OF A REPEATING
PATTERN THAT HAS BEEN IN CONTROL SINCE THIS MIDWEEK. THE LAST OF A
SERIES OF SHORTWAVES WILL DROP SOUTHWARD INTO ARIZONA AND AGAIN FORM
A LOW TO OUR SOUTHWEST SUNDAY NIGHT INTO MONDAY. TODAY`S RUNS ARE
FARTHER WEST THAN YESTERDAY`S...WHICH DOES NOT ALLOW THE BEST
MOISTURE/DYNAMICS/OROGRAPHICS TO MOVE OVER OUR FORECAST AREA. THAT
SAID...THIS DISTURBANCE WILL BE IN CLOSE ENOUGH PROXIMITY FOR ANOTHER
ROUND OF MOUNTAIN SNOWFALL...WITH A CHANCE OF SNOW IN MANY VALLEYS.
THE FAVORED AREA WILL SWITCH FROM THE NORTH TO THE SOUTH LATE SUNDAY
NIGHT...WITH CLEARING OVER THE NORTH DURING THE DAY ON MONDAY. WINDS
DO NOT SEEM TO BE AS STRONG AS YESTERDAY`S SYSTEM...SO DO NOT
ANTICIPATE NEARLY AS MUCH BLOWING SNOW.
WE CONTINUE TO SEE SOME DISCREPANCIES IN RUN-TO-RUN AND BETWEEN-MODEL
SOLUTIONS FOR THE UPCOMING LONG TERM PERIOD. TODAY`S RUNS KEEP THE
AREA DRY THROUGH THE REMAINDER OF THE PERIOD. WE SIT UNDER A DRY AND
COLD NORTHWEST FLOW AS HIGH PRESSURE DOMINATES THE WEST COAST THROUGH
THE GREAT BASIN. THIS PATTERN IS NOW PROGGED TO PERSIST THROUGH THE
WORK WEEK. MODELS INDICATE THAT THERE MAY BE A COUPLE WEAK WAVES THAT
BRUSH THE NORTHERN EDGE...BUT THE TIMING AND TRACK IS BOUND TO CHANGE
WITH FUTURE MODEL RUNS.
TEMPERATURES WILL BE BELOW NORMAL IN THE DRY AIR MASS...ESPECIALLY AT
NIGHT. SOME MODIFICATION IS EXPECTED TOWARDS THE END OF THE PERIOD.
ANY WAVES THAT BRUSH THE AREA WILL ACT TO MODIFY TEMPS...AGAIN MAINLY
AT NIGHT.
&&
.AVIATION /FOR 00Z TAF ISSUANCE/...
SNOW HAS DEVELOPED OVER MANY MOUNTAIN AREAS AND IN SOME SOUTHERN
VALLEYS THIS AFTERNOON. THIS ACTIVITY IS EXPECTED TO BECOME MORE
WIDESPREAD THIS EVENING AND OVERNIGHT. THEREFORE MVFR/IFR VIS/CIGS IS
EXPECTED MUCH OF THE TIME OVER THE MOUNTAINS...AND FOR SHORTER
PERIODS IN THE VALLEYS. BY MIDNIGHT ALL TAF SITES WILL HAVE A CHANCE
OF MVFR/IFR AS THE CHANCE FOR PRECIPITATION SPREADS INTO THE LOWER
VALLEYS. SNOW AND LOW CLOUDS WILL CONTINUE...DIMINISHING FROM THE
NORTH DURING THE AFTERNOON. THEREFORE PERIODS OF MVFR/IFR ARE
EXPECTED THROUGH THE DAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONES
9/12/18.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR ZONE 019.
WINTER WEATHER ADVISORY UNTIL 2 PM MST SATURDAY FOR ZONES 22/23.
UT...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONE 28.
&&
$$
SHORT TERM...JAD
LONG TERM....EH
AVIATION.....EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
305 PM MST FRI DEC 2 2011
.SHORT TERM /TODAY THROUGH SATURDAY NIGHT/...
THE CLOSED LOW OVER AZ FINALLY BEGINNING TO OPEN UP AND IS EXPECTED
TO EJECT THROUGH NM AND THE 4 CORNERS TONIGHT AS THE NEXT TROUGH
DIVES DOWN TO REPLACE IT. MOISTURE HAS SPREAD ACROSS MUCH SE UT AND
WRN CO TODAY AND NICELY CAPTURED ON THE 300K POTENTIAL TEMP
SURFACE...WITH LIGHT SNOW REPORTED OVER HIGHER TERRAIN FROM MOUNT
WERNER ABOVE STEAMBOAT SPGS TO GRAND MESA TO THE SAN JUAN MTNS. SNOW
ALSO ALONG THE SRN BASE OF THE SAN JUANS FROM CORTEZ TO PAGOSA IN THE
UPSLOPE FLOW. RUC MODELS SHOWS A COUPLE WAVES OF ENERGY MOVING UP
FROM THE LOW...SO EXPECT SNOW INTENSITY TO VARY THROUGH THE NIGHT
IN SW CO. CURRENT WINTER HIGHLIGHTS FOR THE SAN JUAN/ABAJO/LA SAL
MTNS AND THE DURANGO-PAGOSA AREA LOOK ON TRACK.
THE SECOND SPLITTING TROUGH WAS DROPPING ACROSS ID AND DRIVEN BY A
120 KT UPPER JET OVER THE PAC NW. THIS TROUGH EXPECTED TO PUSH A COLD
FRONT INTO NE UT/NW CO TONIGHT AND THEN INTO SE UT/SW CO SAT AS IT
FORMS A SECOND CLOSED OVER AZ. RATHER NARROW BAND OF MOISTURE
ASSOCIATED WITH THE TROUGH MOVING INTO NW UT...BUT EXPECT SNOW
COVERAGE TO INCREASE OVER NE UT/NW CO TONIGHT AS THE FRONT
INTERACTS WITH THE MOISTURE IN PLACE AHEAD OF THE AZ LOW. THE FRONT
EXPECTED TO SLOW ACROSS THE N LATE TONIGHT...AND A PERIOD DECENT
NORTHEAST OROGRAPHIC WINDS COMBINED WITH COLD ADVECTION SHOULD BRING
3-6 INCHES OF SNOW TO THE ERN UINTA MTNS...ESPECIALLY THEIR NORTH
SLOPES. BUT...NORTHEAST WINDS NOT AS STRONG OR AS LONG IN DURATION
AS THE STORM WED NIGHT...SO REFRAINED FROM ANY HIGHLIGHT FOR THE ERN
UINTAS AT THIS TIME. A PERIOD OF GUSTY NE WINDS LIKELY ACROSS NW CO
SAT MORNING AS WELL...BUT AGAIN NOT NEARLY AS STRONG AS WHAT OCCURRED
THU MORNING.
BOTH NAM AND GFS INDICATE A WEAK 700 MB LOW FORMS OVER WRN CO
TONIGHT/SAT MORNING. BANKING ON ENHANCED LOW LEVEL CONVERGENCE
AND EVENTUAL FRONTAL PASSAGE TO ENHANCE SNOWFALL FROM GRAND MESA TO
THE WEST ELKS. WEST ELKS SHOULD ALSO BENEFIT FROM SOME MOIST
SOUTHERLY OROGRAPHIC FLOW TONIGHT...WHILE TRAILING NORTHERLY FLOW MAY
KEEP SOME LIGHT SNOW OVER GRAND MESA INTO SAT EVENING. AS SUCH...
ELECTED TO INCLUDE THE GRAND MESA AND WEST ELKS /ZONES 9 AND 12/ IN A
LOW-END ADVISORY TONIGHT INTO SAT EVENING FOR 4 TO 9 INCHES OF
SNOW. THE 700 MB LOW SHOULD ALSO BRING SNOW TO MANY CENTRAL VALLEYS
BUT WITH LITTLE ACCUMS EXPECTED.
SNOW DIMINISHES SAT NIGHT WITH CLEARING FROM THE NW. ERN UT/WRN CO
SHOULD BE IN BETWEEN SYSTEMS SUNDAY AS MODELS SHOW YET A THIRD
SPLITTING TROUGH APPROACHING FROM THE N LATE IN THE WEEKEND. WILL
TREND THE CHANCE OF PRECIP UP AGAIN ACROSS THE NORTHERN MTNS SUNDAY
AFTERNOON AS A RESULT.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE EARLY PART OF THE LONG TERM IS A CONTINUATION OF A REPEATING
PATTERN THAT HAS BEEN IN CONTROL SINCE THIS MIDWEEK. THE LAST OF A
SERIES OF SHORTWAVES WILL DROP SOUTHWARD INTO ARIZONA AND AGAIN FORM
A LOW TO OUR SOUTHWEST SUNDAY NIGHT INTO MONDAY. TODAY`S RUNS ARE
FARTHER WEST THAN YESTERDAY`S...WHICH DOES NOT ALLOW THE BEST
MOISTURE/DYNAMICS/OROGRAPHICS TO MOVE OVER OUR FORECAST AREA. THAT
SAID...THIS DISTURBANCE WILL BE IN CLOSE ENOUGH PROXIMITY FOR ANOTHER
ROUND OF MOUNTAIN SNOWFALL...WITH A CHANCE OF SNOW IN MANY VALLEYS.
THE FAVORED AREA WILL SWITCH FROM THE NORTH TO THE SOUTH LATE SUNDAY
NIGHT...WITH CLEARING OVER THE NORTH DURING THE DAY ON MONDAY. WINDS
DO NOT SEEM TO BE AS STRONG AS YESTERDAY`S SYSTEM...SO DO NOT
ANTICIPATE NEARLY AS MUCH BLOWING SNOW.
WE CONTINUE TO SEE SOME DISCREPANCIES IN RUN-TO-RUN AND BETWEEN-MODEL
SOLUTIONS FOR THE UPCOMING LONG TERM PERIOD. TODAY`S RUNS KEEP THE
AREA DRY THROUGH THE REMAINDER OF THE PERIOD. WE SIT UNDER A DRY AND
COLD NORTHWEST FLOW AS HIGH PRESSURE DOMINATES THE WEST COAST THROUGH
THE GREAT BASIN. THIS PATTERN IS NOW PROGGED TO PERSIST THROUGH THE
WORK WEEK. MODELS INDICATE THAT THERE MAY BE A COUPLE WEAK WAVES THAT
BRUSH THE NORTHERN EDGE...BUT THE TIMING AND TRACK IS BOUND TO CHANGE
WITH FUTURE MODEL RUNS.
TEMPERATURES WILL BE BELOW NORMAL IN THE DRY AIR MASS...ESPECIALLY AT
NIGHT. SOME MODIFICATION IS EXPECTED TOWARDS THE END OF THE PERIOD.
ANY WAVES THAT BRUSH THE AREA WILL ACT TO MODIFY TEMPS...AGAIN MAINLY
AT NIGHT.
&&
.AVIATION /FOR 00Z TAF ISSUANCE/...
SNOW HAS DEVELOPED OVER MANY MOUNTAIN AREAS AND IN SOME SOUTHERN
VALLEYS THIS AFTERNOON. THIS ACTIVITY IS EXPECTED TO BECOME MORE
WIDESPREAD THIS EVENING AND OVERNIGHT. THEREFORE MVFR/IFR VIS/CIGS IS
EXPECTED MUCH OF THE TIME OVER THE MOUNTAINS...AND FOR SHORTER
PERIODS IN THE VALLEYS. BY MIDNIGHT ALL TAF SITES WILL HAVE A CHANCE
OF MVFR/IFR AS THE CHANCE FOR PRECIPITATION SPREADS INTO THE LOWER
VALLEYS. SNOW AND LOW CLOUDS WILL CONTINUE...DIMINISHING FROM THE
NORTH DURING THE AFTERNOON. THEREFORE PERIODS OF MVFR/IFR ARE
EXPECTED THROUGH THE DAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONES
9/12/18.
WINTER STORM WARNING UNTIL 11 PM MST SATURDAY FOR ZONE 019.
WINTER WEATHER ADVISORY UNTIL 2 PM MST SATURDAY FOR ZONES 22/23.
UT...WINTER WEATHER ADVISORY UNTIL 11 PM MST SATURDAY FOR ZONE 28.
&&
$$
SHORT TERM...JAD
LONG TERM....EH
AVIATION.....EH
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1219 PM EST FRI DEC 2 2011
.SYNOPSIS...
STRONG HIGH PRESSURE CENTERED IN THE PLAINS STATES HAS AN EXTENSION
TO THE MID-ATLANTIC COAST BUT IS AWAITING THE PASSAGE OF A WEAK
COLD FRONTAL PASSAGE THROUGH THE MID-ATLANTIC STATES LATER TODAY.
THE HIGH THEN BUILDS STRONGLY INTO NEW ENGLAND SATURDAY AND EDGES
OFFSHORE MONDAY. A COLD FRONT SHOULD BE STALLING OR DRIFTING EAST
FROM THE APPALACHIAN MOUNTAINS MONDAY THROUGH AT LEAST WEDNESDAY
AS A SERIES OF LOW PRESSURE SYSTEMS TRY TO MOVE NORTHEAST ALONG
THE FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT TO MANY CHANGES WITH THIS UPDATE. A FRONTAL BOUNDARY WILL MOVE
ACROSS NEW ENGLAND TODAY. BANDS OF HIGH CIRRUS CLOUDS ARE FORMING
ACROSS THE PHILADELPHIA METRO REGION AND POINTS NORTH, THESE ARE
ACCOUNTED FOR IN UPDATED SKY GRIDS. LATEST 16Z RUC KEEPS AND PRECIP
WELL TO OUR NORTH. THIS FITS NICELY WITH RH VALUES NOT IDEAL FOR
PRECIPITATION ALONG WITH WEEK LIFT CHARACTERIZED BY A LACK OF PVA
AND 700 MB OMEGA. ANY RADAR ECHOS ACROSS THE NORTH THIS AFTERNOON
WILL BE VIRGA. SURFACE TEMPERATURES HAVE REBOUNDED NICELY AHEAD OF
THE FRONT EVEN AFTER A CHILLY START AND HAVE ADJUSTED TEMPERATURE
GRIDS AGAIN BASED OFF OF 17Z METAR OBS. FRONT SHOULD BRING
SOUTHERLY WINDS THIS AFTERNOON SWITCHING TO NORTHWESTERLY, MADE
FEW CHANGES TO WIND. WIND GUSTS GRIDS BETTER MATCH SURROUNDING
WFOS WITH THIS UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
TONIGHT IS A CLEAR NIGHT WITH A BIT OF NW BECOMING NORTH BREEZE
DURING THE NIGHT AND TEMPS COOLING TO ABOUT THE SAME VALUES OR
SLIGHTLY LOWER THAN WHAT OCCURRED THIS FROSTY FRIDAY MORNING.
LOWERED THE TEMPS SLIGHTLY IN THE PHL-TTN URBAN CENTERS WITH NORTH
WIND TONIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
FAIR WEATHER IS EXPECTED ACROSS THE AREA THIS WEEKEND AS HIGH
PRESSURE REMAINS IN CONTROL OF THE WEATHER. BOTH THE EC AND GFS
AGREE THAT THE HIGH WILL CREST OVER THE AREA SAT NIGHT AND THEN
MOVE OFF INTO THE NORTH ATLANTIC SUN. SKIES WILL BE MOSTLY CLR
SAT AND PARTLY TO MOSTLY CLR SUN. CLOUDS MAY ARRIVE LATER SUN WITH
THE RETURN FLOW BEHIND THE HIGH BRINGING MOISTURE FROM OFF THE
OCEAN.
A LOW MOVES ACROSS SRN CANADA SUN NGT INTO MON CAUSING A FRONT TO
DROP DOWN FROM THE NORTH. THIS FRONT STALLS ACROSS THE AREA
ALLOWING ANOTHER LOW TO DEVELOP ON IT AND MOVE ACROSS THE AREA MON
NGT INTO WED. THE GFS AND EC OFFER DIFFERENT SOLUTIONS WITH
REGARDS TO HOW MUCH PRECIP ARRIVES AND WHEN. BOTH MODELS HAVE SOME
QPF ARRIVING TUE...BUT THE EC HAS HEAVIER QPF ACROSS THE AREA WED
NIGHT INTO THU WHILE THE GFS HAS THE BULK OF ITS QPF TUE NIGHT
INTO WED. THE OVERNIGHT EXTENDED GRIDS HAVE MADE ONLY SMALL
CHANGES TO THE EARLIER FCST WITH CHC POPS THROUGH MUCH OF THE MON
NGT-THU PERIOD ATTM. A LITTLE SNOW MAY MIX IN WED NIGHT ACROSS THE
NRN AREAS.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR MOSTLY CLEAR. PATCHY THICK CI ESPECIALLY 16Z-20Z...MAINLY
N OF PHL. SCT CLDS 5000-8000 FT EXPECTED WITH THE LATE AFTN CFP.
W GUSTS TO 15 KTS AT 18Z SHIFT NW AROUND 21Z WITH GUSTS 20 KTS...
ISOLATED GUSTS TO 25 KTS POSSIBLE NEAR 23Z/2.
TONIGHT...VFR CLEAR. NW WIND 5 TO 15 KTS BECOMING N DURING THE NIGHT.
PHILADELPHIA SPECIFIC...HIGH CONFIDENCE FCST OF VFR CLEAR THROUGH
17Z WITH A BAND OF CI POSSIBLE 18Z-20Z. WIND AT 18Z W GUST 15 KT.
AFTER 20Z...WSHIFT NW WITH GUSTS 20 KTS AND A FEW SC/CU 6000-8000
FT. LOW PROB ISO NW GUSTS 25 KTS IN THE 21Z-23Z TIME FRAME.
OUTLOOK...
VFR CONDITIONS EXPECTED SAT AND MUCH OF SUN. LOW CLOUDS MAY ARRIVE
BEHIND THE DEPARTING HIGH LATER SUN INTO MON. POOR FLYING CONDITIONS
TUE INTO THU WITH THE NEXT SYSTEM ARRIVING FROM THE MIDWEST STATES.
&&
.MARINE...
TODAY...LIGHT WIND TO START BECOMING INCREASINGLY GUSTY WEST THIS
AFTN.
TONIGHT...SCA ISSUED. MARGINAL CONFIDENCE IN THIS ADVY FOR SCT
GUSTS 22-25 KTS MAINLY IN THE 23Z-05Z TIME FRAME. 44009 SEAS
EXPECTED TO INCREASE TO 5 FT LATER TONIGHT SO HAVE TWO SEGMENTS...
A NJ SEGMENT FOR THIS EVENING AND A LATER LENGTHIER TIME FRAME
SEGMENT FOR THE DELAWARE ATLC WATERS.
NO HEADLINE POSTED YET FOR LOWER DELAWARE BAY. THAT CAN BE ADDED
LATER BY FUTURE SHIFTS IF CONFIDENCE INCREASES.
STRUGGLED TO GET THE GRIDDED GUSTS TO CRITERIA VIA SEVERAL TOOL
APPLICATIONS.
SREF STILL NOT A HINT OF SUSTAINED 25 KT WINDS ALONG OUR COASTS.
UPDATE: LOWERED WAVE HEIGHTS AGAIN SLIGHTLY FOR THE NEXT FEW
HOURS BASED ON BUOY OBSERVATIONS WILL MONITOR THROUGHOUT THE DAY
WITH RESPECT TO THE SMALL CRAFT ADV SET TO GO INTO EFFECT LATE
THIS AFTERNOON. AGREE WITH PREVIOUS FORECASTER THINKING THAT IT IS
QUESTIONABLE WE MEET SMALL CRAFT ADV CONDITIONS.
OUTLOOK...
HIGH PRESSURE WILL BE ACROSS THE WATERS THIS WEEKEND WITH WINDS
AND SEAS EXPECTED TO REMAIN SUB-SCA THROUGH THE PERIOD. THE HIGH
WILL MOVE AWAY EARLY NEXT WEEK WHILE LOW PRESSURE AND A SERIES OF
FRONTS ARRIVE OVER OUR WATERS MON NGT INTO WED. WINDS AND SEAS
WILL EVENTUALLY RISE INTO SCA CRITERIA PROBABLY BY TUE NIGHT AND
THIS WILL PERSIST INTO THU.
&&
.CLIMATE...
DAILY CLI: GED 1203Z-1207Z TRACE OF SNOW IN CLEAR SKY REMOVED FROM
THE 430PM CLI RUN.
RAN THE MONTHLY CLM`S WITH JUST CURSORY CHECK OF THE DATA. IF YOU
NOTICE ANY ERRORS PLEASE GIVE US A CALL.
YOU SAW THE RER`S ISSUED EARLY THURSDAY MORNING REGARDING MONTHLY
AND SEASONAL RANKING OF THE TEMPS/QPF!
LA NINA OHIO VALLEY STORM TRACK CONTS TO LOOK ACTIVE AND MOST
INDICATIONS ARE THAT THE PRECIPITATION EVENT FROM LATE MONDAY INTO
WEDNESDAY WILL AT SOME POINT RAISE THE YEARLY WATER EQUIVALENT
PCPN TOTAL AT KABE TO RECORD VALUES...NEEDING ONLY .16 INCHES TO
EXCEED THE YEARLY RECORD OF 67.69 INCHES.
NOTING THAT PHL AVG TEMP IS HEADED FOR ITS 13TH CONSECUTIVE ABOVE
NORMAL DAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 1 AM EST
SATURDAY FOR ANZ450>453.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EST
SATURDAY FOR ANZ454-455.
&&
$$
SYNOPSIS...DRAG/GORSE
NEAR TERM...GAINES
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...DRAG/O`HARA
MARINE...DRAG/GAINES/O`HARA
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
353 PM EST FRI DEC 2 2011
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO PENNSYLVANIA TONIGHT AND CONTROL THE
LOCAL WEATHER UNTIL COLD FRONT MOVES IN FROM THE NORTHWEST EARLY
NEXT WEEK. THE COLD FRONT WILL MOST LIKELY STALL OVER THE STATE
AND LEAD TO RAIN FOR THE FIRST HALF OF THE WEEK. COLDER TEMPERATURES
WITH SCATTERED SNOW SHOWERS WILL THEN ENSUE IN THE MID WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
MID DECK ROLLING ACROSS THE AREA CURRENTLY WILL SLIDE TO THE EAST
AND DISSIPATE SOME AS IT DOES SO. MOST LOCATIONS WILL STAY FAIR
ALL EVENING. NEAR TERM GUID PORTRAYS THE LOW CLOUDS OVER THE
NORTHWEST LASTING FOR ONLY A FEW HOURS THIS EVENING...WITH JUST A
FLURRY OR TWO IN THE NW. HRRR PAINTS SOME FLURRIES IN THE
SW/LAURELS...BUT WILL NOT MENTION AT THIS POINT. GUSTY WNW WINDS
IN THE MTS WILL DIE DOWN QUICKLY THIS EVENING AS THE HIGH PRESSURE
BUILDS IN FROM THE WEST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CLEAR AND CALM FOR THE OVERNIGHT WITH AXIS OF SFC HIGH PRESSURE
OVERHEAD BEFORE SUNRISE. SOME OF THE COLDEST TEMPERATURES SO FAR
THIS YEAR. STILL LOOKING AT MINS AROUND 20F NEAR THE NEW YORK
BORDER...BUT WOULD NOT BE SURPRISED TO SEE READINGS DROP INTO THE
MID TEENS IN SOME OF THE NORMALLY COLDER SHELTERED VALLEY SPOTS.
LLVL FLOW GOES S/SERLY DURING THE DAY SAT...AND TEMPS SHOULD
RISE BACK TO NEAR NORMALS AFTER THE COLD START. CLOUDS WILL BE
TOUGH TO FIND EARLY...BUT HIGH CLOUDS FROM WARM ADVECTION ALOFT
WILL SHOW UP AS THE DAY CONTINUES. JUST P/C FOR SAT NIGHT WITH
SFC HIGH STRETCHED OUT ALL ALONG THE EAST COAST. 8H TEMPS RISE TO
+6C TO +8C BY SUN AM. DESPITE THIS...DECOUPLING WILL ALLOW THE
MINS TO DIP TO THE M/U20S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MAINLY DRY CONDITIONS WILL PERSIST INTO SUNDAY.
AN INCREASING SOUTHERLY BREEZE ON SUNDAY WILL HELP TO BOOST THE NEAR
TO SLIGHTLY BELOW NORMAL MAX TEMPS SATURDAY...TO A GOOD 5-7F ABOVE
NORMAL FOR SUNDAY. MAX TEMP DEPARTURES FROM NORMAL WILL BE GREATEST
ACROSS THE WRN MTNS WHERE HIGHS IN THE U40S TO LOWER 50S WILL BE 10F
OF MORE ABOVE NORMAL.
PARTLY TO MOSTLY SUNNY SKIES WILL BE FOUND ACROSS THE ERN HALF OF
THE STATE FOR MUCH OF SUNDAY...WHILE CLOUDS THICKEN UP ACROSS THE
WEST THROUGHOUT THE DAY. THERE WILL BE A CHANCE FOR A FEW SHOWERS
ACROSS THE FAR NW LATE.
PUSHED BACK THE ARRIVAL TIME OF THE RAIN SHIELD THROUGH THE
FORECAST AREA ON MONDAY AS LATEST GEFS HOLDS THE ANAMALOUS PWAT
VALUES BACK INTO OHIO INTO MONDAY. THAT WILL OVERSPREAD THE AREA
LATE MONDAY THROUGH TUESDAY AS THE FRONT CRAWLS ACROSS THE AREA.
INTRODUCED RAIN MIXING WITH AND CHANGING TO SNOW SHOWERS AS THE
COLD AIR MOVES IN TUESDAY NOGHT AND WEDNESDAY. THE TIMING OF THE
COLDER AIR ARRIVAL WITH THE EXITING PRECIP SHIELD WILL LIMIT ANY
APPRECIABLE ACCUMULATIONS.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
HIGH/MID CLOUD SHEET WILLDISSIPATE AS IT MOVES EAST THIS EVE...AND
THE LOW/MVFR ALMOST-IFR DECK IN THE NW WILL ALSO BREAK UP EARLY
TONIGHT. BY 03Z...IT SHOULD BE PRETTY MUCH CLEAR. THE CLEAR SKIES
WILL LAST INTO THE DAYTIME SAT...WITH ONLY HIGH CLOUDS FOR SAT
AFTN/NIGHT. GUSTY WINDS AT THIS TIME WILL DECREASE VERY RAPIDLY
THIS EVENING AS THE HIGH PRESSURE OFF TO THE WEST SETS UP
OVERHEAD. THE HIGH WILL SLOWLY MOVE TO THE EAST COAST THROUGH
SATURDAY NIGHT.
OUTLOOK...
MON...RAIN/LOW CIGS POSSIBLE...MAINLY NW.
TUE...RAIN/LOW CIGS POSSIBLE.
WED...RAIN AREAWIDE TRANSITIONS TO SHSN NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...TYBURSKI
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1255 PM EST FRI DEC 2 2011
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO PENNSYLVANIA TONIGHT AND CONTROL THE
LOCAL WEATHER UNTIL COLD FRONT MOVES IN FROM THE NORTHWEST EARLY
NEXT WEEK. THE COLD FRONT WILL MOST LIKELY STALL OVER THE STATE
AND LEAD TO RAIN FOR THE FIRST HALF OF THE WEEK. COLDER TEMPERATURES
WITH SCATTERED SNOW SHOWERS WILL THEN ENSUE IN THE MID WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
MID DECK ROLLING ACROSS THE AREA CURRENTLY WILL SLIDE TO THE EAST
AND DISSIPATE SOME AS IT DOES SO. MOST LOCATIONS WILL STAY FAIR
ALL EVENING. NEAR TERM GUID PORTRAYS THE LOW CLOUDS OVER THE
NORTHWEST LASTING FOR ONLY A FEW HOURS THIS EVENING...WITH JUST A
FLURRY OR TWO IN THE NW. HRRR PAINTS SOME FLURRIES IN THE
SW/LAURELS...BUT WILL NOT MENTION AT THIS POINT. GUSTY WNW WINDS
IN THE MTS WILL DIE DOWN QUICKLY THIS EVENING AS THE HIGH PRESSURE
BUILDS IN FROM THE WEST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CLEAR AND CALM FOR THE OVERNIGHT WITH AXIS OF SFC HIGH PRESSURE
OVERHEAD BEFORE SUNRISE. SOME OF THE COLDEST TEMPERATURES SO FAR
THIS YEAR. STILL LOOKING AT MINS AROUND 20F NEAR THE NEW YORK
BORDER...BUT WOULD NOT BE SURPRISED TO SEE READINGS DROP INTO THE
MID TEENS IN SOME OF THE NORMALLY COLDER SHELTERED VALLEY SPOTS.
LLVL FLOW GOES S/SERLY DURING THE DAY SAT...AND TEMPS SHOULD
RISE BACK TO NEAR NORMALS AFTER THE COLD START. CLOUDS WILL BE
TOUGH TO FIND EARLY...BUT HIGH CLOUDS FROM WARM ADVECTION ALOFT
WILL SHOW UP AS THE DAY CONTINUES. JUST P/C FOR SAT NIGHT WITH
SFC HIGH STRETCHED OUT ALL ALONG THE EAST COAST. 8H TEMPS RISE TO
+6C TO +8C BY SUN AM. DESPITE THIS...DECOUPLING WILL ALLOW THE
MINS TO DIP TO THE M/U20S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MAINLY DRY CONDITIONS WILL PERSIST INTO SUNDAY.
AN INCREASING SOUTHERLY BREEZE ON SUNDAY WILL HELP TO BOOST THE NEAR
TO SLIGHTLY BELOW NORMAL MAX TEMPS SATURDAY...TO A GOOD 5-7F ABOVE
NORMAL FOR SUNDAY. MAX TEMP DEPARTURES FROM NORMAL WILL BE GREATEST
ACROSS THE WRN MTNS WHERE HIGHS IN THE U40S TO LOWER 50S WILL BE 10F
OF MORE ABOVE NORMAL.
PARTLY TO MOSTLY SUNNY SKIES WILL BE FOUND ACROSS THE ERN HALF OF
THE STATE FOR MUCH OF SUNDAY...WHILE CLOUDS THICKEN UP ACROSS THE
WEST THROUGHOUT THE DAY. THERE WILL BE A CHANCE FOR A FEW SHOWERS
ACROSS THE NW LATE.
AS THE UPPER FLOW BACKS...AND THE NRN AND SRN STREAM TROFS TO OUR
WEST PHASE/AMPLIFY...THE CFRONT WILL SLOW SIGNIFICANTLY ACROSS THE
REGION /AND MAY EVEN STALL OUT FOR A PERIOD MONDAY NIGHT THROUGH
TUESDAY/.
GFS AND EC BOTH INDICATE A PIECE OF THE SRN STREAM ENERGY HELPING TO
FORM A QUASI-CLOSED UPPER LOW ACROSS THE OHIO VALLEY...THEN OPENING
UP THE WAVE AS IT MOVES INTO THE NE U.S. DURING THE MIDWEEK.
THE TIMING OF THIS FEATURE IS MUCH SLOWER ON THE EC...AND ALSO
STRONGER...WHICH SUPPORTS A MORE WIDESPREAD AND MODERATELY HEAVY
RAIN EVENT...MIXING WITH OR CHANGING TO SNOW ACROSS THE WRN MTNS
WEDNESDAY THROUGH WED NIGHT. AGAIN THE GFS IS MORE PROGRESSIVE AND
WEAKER...LEADING TO PRECIP IN THE FORM OF SHOWERS OR A FEW PERIODS
OF STEADIER RAIN EXITING OUR ERN COUNTIES TUESDAY NIGHT.
GEFS PLUMES...WITH A LARGE SPREAD IN TIMING/AMOUNT AND TYPE OF
PRECIP...CAPTURE THIS HIGH UNCERTAINTY. THE CONFIDENCE THE EVENT
OCCURRING IN ONE FORM OR ANOTHER IS HIGH THOUGH.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
HIGH/MID CLOUD SHEET WILLDISSIPATE AS IT MOVES EAST THIS EVE...AND
THE LOW/MVFR ALMOST-IFR DECK IN THE NW WILL ALSO BREAK UP EARLY
TONIGHT. BY 03Z...IT SHOULD BE PRETTY MUCH CLEAR. THE CLEAR SKIES
WILL LAST INTO THE DAYTIME SAT...WITH ONLY HIGH CLOUDS FOR SAT
AFTN/NIGHT. GUSTY WINDS AT THIS TIME WILL DECREASE VERY RAPIDLY
THIS EVENING AS THE HIGH PRESSURE OFF TO THE WEST SETS UP
OVERHEAD. THE HIGH WILL SLOWLY MOVE TO THE EAST COAST THROUGH
SATURDAY NIGHT.
OUTLOOK...
MON...RAIN/LOW CIGS POSSIBLE...MAINLY NW.
TUE...RAIN/LOW CIGS POSSIBLE.
WED...RAIN AREAWIDE TRANSITIONS TO SHSN NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/CERU
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
329 PM CST FRI DEC 2 2011
.SHORT TERM...
TONIGHT AND SATURDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
SHORTWAVE ENERGY EJECTING OUT OF A TROUGH IN THE SOUTHWEST U.S. WILL
BRING A PLUME OF MOISTURE INTO WISCONSIN TONIGHT THROUGH SUNDAY
MORNING. THIS PLUME IS APPARENT IN THE LATEST WATER VAPOR IMAGERY.
THIS TROUGH/SHORTWAVE WILL PHASE WITH A NORTHERN STREAM TROUGH OVER
THE WEEKEND...CREATING A PROLONGED PRECIP EVENT ACROSS WISCONSIN.
MODELS ARE IN FAIR AGREEMENT ABOUT WAITING UNTIL AFTER MIDNIGHT FOR
THE WALL OF WATER...OR DEEP MOISTURE...TO REACH SOUTH CENTRAL WI.
WHILE THERE MAY BE SOME PRECIP IN THE FORECAST AREA BEFORE 3
AM...THE MAIN SURGE WILL HIT MOST OF THE AREA BETWEEN 3 AND 6 AM.
THE PRECIP MAY HOLD OFF IN KENOSHA AND MILWAUKEE UNTIL RIGHT AROUND
6 AM/12Z. UPPER LEVEL DIVERGENCE INCREASES TONIGHT ALONG WITH
MODERATE 700MB UPWARD MOTION. ISENTROPIC LIFT SEEN ON THE 290K
ISENTROPIC LEVEL WITH CONDENSATION PRESSURE DEFICITS BELOW 5 MB ON
THE NAM BY SUNRISE SATURDAY.
PRECIP WILL MAINLY BE IN THE FORM OF RAIN IN THE ENTIRE FORECAST
AREA. THE ONLY EXCEPTION WILL BE AROUND THE DELLS AND GREEN
LAKE/MARQUETTE COUNTIES WHERE THE EVENT COULD BEGIN AS SNOW AND
SWITCH TO RAIN. WITH THE STRONG WARM AIR ADVECTION...SFC TEMPS ARE
EXPECTED TO WARM TO JUST ABOVE FREEZING WITH THE ONSET OF
PRECIPITATION...THUS LIMITING THE FREEZING RAIN OR SNOW POTENTIAL.
THE CENTER OF THE SURFACE LOW PRESSURE WILL TRACK RIGHT ACROSS SOUTH
CENTRAL WI LATE SAT AFTERNOON INTO SUNDAY MORNING...SO A LULL IN THE
PRECIPITATION IS EXPECTED IN SOUTHEAST WI...EAST OF MADISON. THE
LULL SHOULD BE FROM AROUND 2 PM SAT THROUGH SAT EVENING IN
MILWAUKEE. CLOUD COVER DURING THIS TIME IS UNCERTAIN...AS MODELS
SUGGEST CLEARING AND EXPERIENCE SUGGESTS STRATUS CLOUDS AND POSSIBLY
LIGHT FOG.
SATURDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
THE SHORTWAVE TROUGH LIFTING NEWD THROUGH THE GREAT PLAINS WILL
REACH NRN WI BY 12Z SUN AND WILL AID IN MINOR DEEPENING OF THE SFC
LOW AS IT TRACKS FROM ERN KS TO SE WI. A DRY SLOT WILL INITIALLY
BE OVER ERN WI SAT EVENING BUT WILL SHIFT EWD WITH A 60 KT LOW
LEVEL JET STREAM TO BRING A NEW SURGE OF WARM AND MOIST ADVECTION
AND SFC-850 MB FRONTOGENESIS. PWS TO INCREASE TO 0.80-0.90 INCHES WITH
WIDESPREAD MDT RAIN EXPECTED. THE CONSENSUS OF THE THERMAL FIELDS
WILL BRING A MIXTURE OF LGT RAIN AND LGT SNOW TO THE FAR WRN CWA
BETWEEN 09-12Z. PCPN TO QUICKLY DIMINISH SUN AM AS THE LOW LEVEL
JET STREAM SHIFTS INTO LOWER MI. LIKELY POPS EXPECTED EARLY IN
THE DAY FOR THE NE CWA WITH CHANCES ELSEWHERE. LGT RAIN WILL
CHANGE TO OR MIX WITH LGT SNOW BUT SNOW ACCUMULATIONS WILL LIKELY
REMAIN UNDER ONE HALF INCH IN THE NRN AND WRN CWA WITH TRACE
AMOUNTS AT BEST IN SE WI.
COLD AND DRY ADVECTION AND SUBSIDENCE SHOULD BE ENOUGH FOR CLOUD
COVER TO BECOME FEW-SCATTERED FOR SUN NT INTO MONDAY. A WEAKENING
LOW PRESSURE AREA AND SHORTWAVE TROUGH WILL THEN MOVE FROM THE NRN
PLAINS INTO THE GREAT LAKES FOR MONDAY. THE ONLY RESULT WILL BE A
DRY COLD FRONT WITH THE UPSTREAM POLAR HIGH OVER THE NRN AND
CENTRAL GREAT PLAINS.
.LONG TERM...
TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
A HIGH PRESSURE RIDGE ASSOCIATED WITH THE POLAR HIGH OVER THE
CENTRAL PLAINS WILL MOVE ACROSS WI FOR TUE/TUE NT WHILE A LONG
WAVE UPPER TROUGH AND SFC TROUGH BRINGS PCPN TO SRN AND ERN UNITED
STATES. FOR THE REMAINDER OF THE WEEK A STRONG AND VERY LARGE
CYCLONE WILL MOVE ACROSS NRN CANADA AND OCCLUDE OVER AND NORTH OF
THE HUDSON BAY AREA LATER IN THE WEEK. THE NRN USA WILL BE ON THE
SRN FRINGES OF THIS CYCLONE WITH DRY WNWLY WINDS AND GRADUAL COLD
ADVECTION. DURING THIS TIME A 1040 MB ARCTIC HIGH WILL SLIDE SWD
ALONG THE LEE OF THE CANADIAN ROCKIES AND EVENTUALLY INTO THE MID
MO RIVER VALLEY ON FRI. SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED
LATER NEXT WEEK WITH THE LACK OF SNOW COVER INHIBITING GREATER
COOLING.
&&
.AVIATION/00Z TAFS/...
CLEAR SKIES THROUGH THE EVENING UNDER THE HIGH PRESSURE. HOWEVER
SOUTH WINDS DEVELOPING AHEAD OF LOW PRESSURE FROM WESTERN OKLAHOMA
TO MINNESOTA WILL BRING INCREASING/THICKENING AND LOWERING HIGH/MID
LEVEL CLOUDS THIS EVENING...FOLLOWED BY MVFR/IFR CIGS AND VSBYS...
ESPECIALLY IN SOUTH CENTRAL WISCONSIN DURING THE EARLY MORNING HOURS
SATURDAY. SOME FREEZING RAIN POTENTIAL MAINLY NORTH AND WEST OF
MADISON TO NEAR FOND DU LAC.
THERE WILL BE A LULL IN THE PRECIP SAT AFTERNOON. NOT SURE IF
CEILINGS WILL TANK WITHIN THE LULL AS THE SFC LOW MOVES OVERHEAD
DURING THIS TIME. LOW CIGS EXPECTED EARLY SAT EVENING...WHICH SHOULD
COME UP A BIT WHEN THE NEXT ROUND OF PRECIP HITS. PRECIP TYPE SHOULD
BE ALL RAIN FROM TONIGHT THROUGH SATURDAY NIGHT AT ALL TAF SITES.
LOW LEVEL WIND SHEAR EXPECTED TONIGHT INTO SATURDAY MORNING AS LOW
LEVEL JET MOVES OVERHEAD. NAM IS STRONGER WITH THE WINDS THAN THE
GFS...AND RUC IS IN BETWEEN. LLWS WILL BE POSSIBLE ONCE AGAIN SAT
NIGHT AS A NEW SURGE OF WARM AIR ADVECTION MOVES INTO SOUTHEAST WI.
&&
.MARINE...
SOUTH WINDS WILL INCREASE TONIGHT AND WINDS AND WAVES ARE EXPECTED
TO REACH LOWER-END SMALL CRAFT ADVISORY CONDITIONS LATE TONIGHT INTO
SATURDAY. WINDS AND WAVES WILL BE HIGH THROUGH SATURDAY
MORNING...THEN THERE WILL BE A LULL IN THE WINDS SATURDAY AFTERNOON
AS THE SURFACE LOW CROSSES SOUTHEAST WISCONSIN. WEST WINDS WILL
INCREASE BEHIND THE LOW ONCE AGAIN SAT NIGHT THROUGH AT LEAST MIDDAY
SUNDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FROM 06Z TONIGHT THROUGH
18Z SUNDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY
FOR LMZ643>646.
&&
$$
TONIGHT/SATURDAY AND AVIATION/MARINE...MRC
SATURDAY NIGHT THROUGH FRIDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1131 AM CST FRI DEC 2 2011
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
347 AM CST FRI DEC 2 2011
MAIN FORECAST CONCERN IS ON PRECIPITATION FOR AFTER MIDNIGHT TONIGHT
THROUGH SUNDAY MORNING AND POSSIBLE HAZARDS.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH OVER SOUTHWEST CANADA...RIDGING OUT
AHEAD OVER THE NORTHERN PLAINS INTO MANITOBA...AND TROUGHING OVER
THE LAKE MICHIGAN AREA. ALSO OF NOTE IS IN THE SOUTHERN STREAM OF AN
UPPER LOW OVER THE DESERT SOUTHWEST. THE FORECAST AREA LIES IN
SUBSIDENCE IMMEDIATELY BEHIND THE LAKE MICHIGAN TROUGH...PROMOTING
HIGH PRESSURE AT THE SURFACE. IN FACT...THE SUBSIDENCE AND DRYING
HAS BEEN ENOUGH TO RESULT IN CLEAR SKIES OVER THE AREA. UPSTREAM 00Z
SOUNDINGS FROM INL AND ABR REFLECT THE DRYING WELL WITH PRECIPITABLE
WATER VALUES UNDER TWO TENTHS OF AN INCH. THE COMBINATION OF THE
CLEAR SKIES AND LIGHT WINDS HAS ALLOWED TEMPERATURES TO DROP INTO
THE TEENS TO MID 20S. TO THE NORTHWEST...A STREAM OF UPPER LEVEL
MOISTURE CAN BE SEEN ACROSS THE NORTHERN PLAINS INTO SOUTH CENTRAL
CANADA ON WATER VAPOR....AHEAD OF THE UPPER TROUGH THERE...WHICH IS
MANIFESTING ITSELF INTO A LARGE ALTOSTRATUS AND CIRROSTRATUS DECK.
TO THE SOUTHWEST...850MB WINDS HAVE BEEN INCREASING OUT OF THE SOUTH
OVER TEXAS DOWNSTREAM OF THE UPPER LOW...BRINGING GULF OF MEXICO
MOISTURE NORTHWARD TOWARDS OKLAHOMA AS SEEN IN GOES PRECIPITABLE
WATER PLOTS.
TODAY AND TONIGHT...A WARM ADVECTION PATTERN LOOKS TO DEVELOP OVER
THE AREA IN RESPONSE TO THE UPPER TROUGH OVER SOUTHWEST CANADA
SPLITTING INTO TWO...WHERE ONE PIECE MARCHES EAST INTO NORTHWEST
ONTARIO AND NORTH DAKOTA BY 12Z SATURDAY. THE OTHER PIECE DIGS SOUTH
TOWARDS THE LAS VEGAS AREA...CAUSING THE CURRENT UPPER LOW IN
ARIZONA TO GET PUSHED EAST INTO NEW MEXICO. CONDITIONS WILL REMAIN
DRY TODAY GIVEN PLENTIFUL DRY AIR AROUND AS SEEN FROM 00Z SOUNDINGS.
IN FACT...SKIES SHOULD STAY CLEAR TO 00Z. WINDS ARE LIKELY TO
INCREASE...THOUGH...AS THE PRESSURE GRADIENT TIGHTENS UP BEHIND THE
DEPARTING SURFACE RIDGE. TONIGHT IS A DIFFERENT STORY. THE SOUTHERLY
RETURN FLOW SEEN OCCURRING OVER TEXAS NOW IS FORECAST TO EXPAND AND
INTENSIFY TONIGHT...RUNNING FROM DEEP SOUTH TEXAS INTO KANSAS...THEN
NORTHEAST INTO THE FORECAST AREA BY 06Z. 850MB WINDS IN THIS ZONE
ARE PROGGED BETWEEN 40-50 KT. PRECIPITABLE WATER VALUES RESPOND BY
JUMPING FROM AROUND 0.25 INCH AT 00Z TO 0.5-0.8 INCHES AT 12Z...
HIGHEST IN THE SOUTHEASTERN PORTION OF THE FORECAST AREA. 0.75
INCHES REPRESENTS 200 PERCENT OF NORMAL. AS THE DEEPER MOISTURE
ISENTROPICALLY LIFTS INTO THE COLDER AIRMASS OVER THE AREA...
ANTICIPATING PRECIPITATION TO BREAK OUT. MODELS ARE IN VERY GOOD
AGREEMENT ON THIS OCCURRING...WITH THE HIGHEST CONSENSUS OVER THE
SOUTHEASTERN TWO-THIRDS OF THE AREA. PLACED 80-100 PERCENT CHANCES
IN THE SOUTHEAST HALF...THEN TRENDED DRIER HEADING UP TO THE
NORTHWEST INTO LOWER PRECIPITABLE WATER VALUES. P-TYPE A LITTLE
TRICKY AS A SURGE OF WARMER AIR ALSO ACCOMPANIES THE MOISTURE SURGE.
850MB TEMPS ARE PROGGED TO WARM TO 0-2C OVER THE SAME AREA WITH THE
HIGHEST PRECIPITABLE WATER. SHOULD BE MOSTLY A RAIN/SNOW SCENARIO AS
SURFACE TEMPERATURES WARM OVERNIGHT...BUT COULD SEE FREEZING RAIN
TOO IF SURFACE TEMPERATURES HAVE NOT WARMED ABOVE FREEZING OR FROM
NOT ENOUGH ICE PRESENT ALOFT YET. ANY SNOW/ICE ACCUMULATION LOOKS
MINIMAL TONIGHT. HAVE NOT INCLUDED ANY FREEZING RAIN/DRIZZLE BECAUSE
UNCERTAINTY IS JUST TOO HIGH.
SATURDAY THROUGH SUNDAY...MODELS ARE ALL IN VERY GOOD AGREEMENT
KICKING OUT THE UPPER LOW FROM NEW MEXICO AT 12Z SATURDAY NORTHEAST
AS A SHEARING OUT SHORTWAVE. IN ADDITION...THE SHORTWAVE SHOULD GET
ACCELERATED NORTHEAST OVERNIGHT TONIGHT INTO SUNDAY IN RESPONSE TO
MORE TROUGHING DROPPING SOUTH INTO THE NORTHERN PLAINS. THERE ARE
SOME SLIGHT DIFFERENCES WITH RESPECT TO THE ASSOCIATED SURFACE LOW
WITH THE SHORTWAVE...WHICH HAS IMPLICATIONS ON THE TRACK AND
INTENSITY OF THE DEFORMATION PRECIPITATION ON THE NORTH SIDE OF THE
LOW. THE 02.00Z GFS IS THE WEAKEST WITH THE LOW AND FURTHEST
SOUTHEAST...HAVING IT TRACK ACROSS NORTHEAST ILLINOIS AT 12Z SUNDAY.
THE 02.00Z NAM IS FARTHEST NORTHWEST AND FASTEST...CROSSING THE BAY
OF GREEN BAY AT 12Z SUNDAY. THE 02.00Z ECMWF/UKMET IS A COMPROMISE.
FOR NOW FOLLOWED THE COMPROMISE APPROACH...SINCE THE GFS SOLUTION IS
PLAUSIBLE IF MORE CONVECTION CAN OCCUR THAN CURRENTLY PROGGED DOWN
OVER THE SOUTHERN PLAINS. ON THE FLIP SIDE...THERE HAS BEEN QUITE A
BIT OF CONSISTENCY WITH THE ECMWF AND NAM SOLUTIONS. SATURDAY
MORNING SHOULD BE A CONTINUATION OF PRECIPITATION FROM AFTER
MIDNIGHT TONIGHT...DUE TO PERSISTENT ISENTROPIC LIFT. PRECIPITATION
THEN LOOKS TO INTENSIFY IN THE AFTERNOON...PARTICULARLY OVER THE
NORTHWEST HALF OF THE FORECAST AREA...AS THE DEFORMATION AREA OF THE
SURFACE LOW APPROACHES. HEAVIEST PRECIPITATION STILL LOOKS TO OCCUR
SATURDAY EVENING WHEN STRONGEST LOW TO MID-LEVEL FRONTOGENESIS MOVES
ACROSS. IN FACT...CROSS-SECTIONS SHOW THE PRESENCE OF SOME NEGATIVE
EPV ON TOP OF THE FRONTOGENESIS ZONE...SUGGESTING CONVECTIVE
ELEMENTS ARE POSSIBLE. AGAIN...THE HEAVIEST PRECIPITATION LOOKS TO
END UP OVER THE NORTHWEST HALF OF THE FORECAST AREA. WITH SNOW TO
WATER RATIOS LIKELY TO END UP SOMEWHERE AROUND 10 TO 1 AS AN AVERAGE
FOR SATURDAY AND SATURDAY NIGHT...COMBINED WITH QPF AMOUNTS AROUND
0.60 OF AN INCH...TOTAL SNOWFALL WOULD COME OUT TO AROUND 6 INCHES.
GIVEN THAT THE NORTHWEST HALF OF THE FORECAST AREA HAS NOT REALLY
SEEN ITS FIRST SIGNIFICANT SNOW...HAVE ISSUED A WINTER STORM WATCH
FOR THAT AREA. BIGGEST CONCERN OF THE WATCH IS SATURDAY AFTERNOON
AND EVENING...ESPECIALLY TOO WITH THE HOLIDAY SHOPPING/TRAVEL TAKING
PLACE. FOR THE SOUTHEAST END OF THE FORECAST AREA...MAJORITY OF THE
PRECIPITATION MAY FALL AS RAIN OR A RAIN/SNOW MIX AS A SURGE OF WARM
AIR COMES IN. NEW 02.06Z NAM SUGGESTS EVEN A WARMER SURGE. LA CROSSE
COUNTY KEPT OUT OF THE WATCH DUE TO RAIN MIX EXPECTED ON SATURDAY.
FOR BOTH SATURDAY AND SATURDAY NIGHT...INCREASED PRECIPITATION
CHANCES ANYWHERE FROM 10 TO 30 PERCENT GIVEN GOOD CONTINUITY AND
MODEL AGREEMENT. PRECIPITATION SHOULD DIMINISH PRETTY QUICK ON
SUNDAY...THOUGH DID KEEP SOME 20 PERCENT CHANCES GOING IN THE
AFTERNOON FOR CENTRAL WISCONSIN WITH LINGERING UPPER TROUGHING.
CERTAINLY WILL BE COOLER ON SUNDAY WITH SNOW COVER AND 850MB TEMPS
OF -6 TO -8C MOVING IN.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO THE TROUGHING COMING
INTO THE NORTHERN PLAINS ON SUNDAY. GOOD AGREEMENT ON THIS UPPER
TROUGH HEADING EAST INTO THE FORECAST AREA ON MONDAY. HOWEVER...ALL
OF THE BETTER FORCING/MOISTURE APPEAR TO HEAD TO THE NORTH OF THE
AREA. AS SUCH...HAVE CONTINUED A DRY SUNDAY NIGHT AND ONLY KEPT A 20
PERCENT CHANCE IN FOR TAYLOR/CLARK COUNTIES ON MONDAY. COULD SEE
CHANCES BEING COMPLETELY REMOVED FOR MONDAY IF TRENDS CONTINUE.
ALTHOUGH PRECIPITATION LOOKS LIMITED...THE COLD AIR WILL NOT BE.
850MB TEMPS ARE PROGGED TO FALL EVEN FURTHER...DROPPING TO AT LEAST
-8 TO -12C BY 00Z TUESDAY...IF NOT A LITTLE COOLER THAN THAT AS
NOTED BY THE 02.00Z GFS. WENT WITH A BLEND OF GUIDANCE FOR LOWS AND
HIGHS DURING THIS PERIOD...WHICH END UP 5 TO 10 DEGREES COLDER THAN
SATURDAY NIGHT AND SUNDAY.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY NIGHT
347 AM CST FRI DEC 2 2011
AFTER A BUSY EARLY PART TO THE WEEKEND FOR THE WEATHER...MUCH OF THE
EARLY AND MIDDLE PORTION OF NEXT WEEK LOOK QUIET AND COOL. 02.00Z
ECMWF/CANADIAN/GFS/GFS ENSEMBLES ARE IN GOOD AGREEMENT FOR MUCH OF
THE LONG TERM FORECAST INDICATING THE TROUGHING THAT WAS OVER THE
AREA MONDAY LINGERING INTO TUESDAY...THEN JUST GRADUAL DEEP
TROUGHING FORMING OVER MUCH OF CANADA INTO THE NORTHERN U.S. HEADING
INTO THURSDAY. THIS TYPE OF PATTERN SUGGESTS LITTLE MOISTURE TO WORK
WITH AND AS SUCH MODEL QPF FORECASTS ARE PRETTY MUCH NOTHING. NEXT
REAL CHANCE OF PRECIPITATION COMES MAYBE ON THURSDAY NIGHT WITH SOME
HINTS OF SHORTWAVE TROUGHING DIGGING INTO THE WESTERN U.S....
RESULTING IN A WARM ADVECTION PATTERN DOWNSTREAM. STILL...THE
PRECIPITATION CHANCE LOOKS PRETTY SMALL. THE BIG THING IS
TEMPERATURES. 850MB TEMPS ARE PROGGED TO DROP TO ONLY SLOWLY RECOVER
TO -6 TO -8C ON WEDNESDAY...THEN FALL BACK TO -12 TO -18C OR SO FOR
THURSDAY. THEREFORE...TEMPERATURES ARE FORECAST TO STAY BELOW
NORMAL. FOLLOWED A CONSENSUS OF GUIDANCE FOR TEMPERATURES. CANNOT
RULE A PERIOD OF SOME BELOW ZERO TEMPERATURES FOR LOWS TOO...
ESPECIALLY FOR SOME OF THE TYPICAL COLD SPOTS.
&&
.AVIATION...THROUGH 18Z SATURDAY
1131 AM CST FRI DEC 2 2011
HIGH PRESSURE SLIDES EAST OF THE AREA TONIGHT AS AN AREA OF LOW
PRESSURE GETS ORGANIZED ACROSS THE SOUTHERN PLAINS. BIGGEST
CONCERN IS ON PRECIPITATION ONSET TIME AND LOWERING CEILINGS AFTER
09Z TONIGHT. VFR CONDITIONS EXPECTED THROUGH 09Z...AFTER WHICH LOW
LEVEL MOISTURE GETS PULLED NORTHWARD AHEAD OF THE LOW. CEILINGS
WILL LIKELY LOWER AND PRECIPITATION BREAK OUT BETWEEN 09Z-12Z.
HOWEVER FEEL CEILINGS WILL REMAIN IN THE VFR CATEGORY UNTIL AT
LEAST 12Z. FIRST SURGE OF PRECIPITATION LOOKS TO BE IN THE FORM OF
LIGHT SNOW AND HAVE TRENDED TAFS IN THIS DIRECTION WITH MVFR
CEILINGS AND VISIBILITIES. WITH WARMER AIR BEING PULLED
NORTHWARD...DID MIX WITH SNOW WITH SOME RAIN AT KLSE AFTER 16Z.
LATER SHIFTS WILL HAVE TO WATCH FOR LOWER CEILINGS/VISIBILITIES IN
THE 10Z-18Z TIME FRAME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
347 AM CST FRI DEC 2 2011
WI...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR WIZ017-029-032>034.
MN...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR MNZ079-086>088-094-095.
IA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT FOR IAZ008-009-018.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION...RABERDING