AREA FORECAST DISCUSSION
NWS PUEBLO CO
1049 AM MST SAT DEC 31 2011
.AVIATION...
STARTING TO SEE STRONGER WINDS COMING DOWN THE PALMER DIVIDE WITH
A QUICK DIAL IN TO THE KCOS ASOS REVEALING A 50 KT GUST IN THE
PAST FEW MINUTES. WIND DIRECTION HAS SHIFTED FROM A NORTHERLY
COMPONENT AS SFC PRESSURE RISES ARE NOW STARTING TO DROP IN FROM
THE NORTHWEST. RADAR SHOWS FINE LINE ON THE EDGE OF THESE STRONGER
WINDS JUST TO THE NORTH OF KPUB AND SHOULD BE MOVING IN DURING BY
18Z. WILL CARRY GUST TO 50 KTS FOR KCOS AND KPUB FOR THE NEXT FEW
HOURS. WINDS SHOULD EDGE DOWN SOME AFTER 21Z AND BECOME LIGHT
AFTER 02-03Z. MODELS HAVE BEEN HANDLING KALS WINDS POORLY AND HAVE
RELIED HEAVILY ON HIGH RES WRF MODEL AND SFC OBS. WINDS ALREADY
GUSTING FROM THE WEST AT 32 KTS. COULD BRIEFLY SEE A GUST TO 40-45
KTS AS UPPER TROF AXIS PASSES. WILL BE MONITORING THIS TAF SITE
CLOSELY FOR POSSIBLE UPDATES AS NEEDED. -KT
&&
.PREV DISCUSSION... /ISSUED 953 AM MST SAT DEC 31 2011/
UPDATE...
IMPRESSIVE 8+ MB 3 HR PRESSURE RISES SWINGING THROUGH NORTHWEST CO
ATTM BEHIND UPPER TROF. WINDS HAVE BEEN GUSTING OVER 90 KTS AT
KMYP...WITH SALIDA AND BUENA VISTA AIRPORTS SEEING GUSTS TO 55
KTS. UPPER TROF IN WV AND LATEST MODEL RUNS IS CERTAINLY MORE AMPLIFIED
THAN RUNS FROM YESTERDAY...AND LATEST LOCAL 4KM WRF AND 12Z NAM12
SHOWING A WIDESPREAD SWATH OF 50-65 KT WINDS AT 800 MB SPREADING
ACROSS THE SOUTHEAST PLAINS. STRONG DOWNWARD FORCING AND MIXING
SHOULD BE SUFFICIENT TO TAP THESE WINDS ALOFT...RESULTING IN WIND
GUST POTENTIAL OF 65 MPH ACROSS THE PLAINS...PERHAPS STRONGER IN
SOME LOCATIONS. WINDS IN THE SAN LUIS VALLEY HAVE ALSO BEEN MUCH
STRONGER THAN MODELS PREDICTED...AND MTN TOP WINDS ACROSS THE SAN
JUANS AND LA GARITAS ARE EXPECTED TO INCREASE TO AROUND 70 KTS AT
PEAK LEVEL SHORTLY. THUS...HAVE EXPANDED HIGH WIND WARNINGS TO
INCLUDE THE REMAINDER OF THE SOUTHEAST PLAINS...AS WELL AS THE
HIGHER AREAS OF THE EASTERN SAN JUANS AND LA GARITAS. ITS POSSIBLE
THAT SOME OF THESE STRONG GUSTS MAY DESCEND INTO THE VALLEY EDGES
AND NECESSITATE FURTHER EXPANSION OF THE WARNINGS. WILL CONTINUE TO
MONITOR CLOSELY. -KT
PREV DISCUSSION... /ISSUED 333 AM MST SAT DEC 31 2011/
SHORT TERM...
(TODAY AND TONIGHT)
.STRONG WINDS EXPECTED ACROSS THE CENTRAL AND EASTERN
MOUNTAINS...NORTHERN I-25 CORRIDOR...AND NRN PORTIONS OF THE
SOUTHEAST PLAINS TODAY...
CURRENTLY...IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS CLEARLY
SHOWS THE APPROACHING SHORTWAVE CROSSING THE GREAT BASIN AND
NORTHERN ROCKIES THIS AM...WITH THE TROF AXIS ROUGHLY OVER ID AND W
MT AS OF 3 AM. SLC SFC OBS HAVE REPORTED HEFTY PRESSURE
RISES...WHILE CLOSER TO HOME WINDS HAVE BEEN ON THE INCREASE ACROSS
THE HIGHER ELEVATIONS. THE SENSOR ON PIKES PEAK REPORTED AN 84 MPH
GUSTS AT 1 AM...SO STRONG WINDS ARE COMING AS THE PRESSURE GRADIENT
TIGHTENS.
TODAY...THE UPPER JET THAT IS CARVING OUT THE BASE OF THIS SHORTWAVE
TROUGH HAS A CORE OF 100-110 KTS...AND IS EXPECTED TO SLIDE ACROSS
THE STATE TODAY. STRONGW-SW WINDS THIS MORNING WILL QUICKLY SHIFT TO
A NW DIRECTION AND STRENGTHEN THROUGH THE MORNING AS THE TROUGH
MOVES EAST...WITH BOTH THE NAM AND GFS MODELS INDICATING THAT THE
TROUGH AXIS WILL BE NEAR THE CO AND KS BORDER BY MIDDAY. MODEL CROSS
SECTIONS SHOW A RAPID INTENSIFICATION OF WINDS AS THEY DROP TOWARDS
THE SFC BETWEEN 12Z AND 18Z...AND GUSTS TO 60 MPH FOR THE LOWER
ELEVATIONS ARE PROBABLE THIS MORNING. HOW WIDESPREAD THESE GUSTS
WILL BE IS A QUESTION...BUT FEEL THAT MANY WILL EXPERIENCE HIGH
WINDS TODAY. THEREFORE...THE HIGH WIND WARNING ALREADY IN PLACE FOR
MUCH OF THE HIGHER TERRAIN...THE UPPER ARKANSAS RIVER VALLEY...MUCH
OF THE I25 CORRIDOR AND FOR PORTIONS OF THE PLAINS ALONG HIGHWAY 50
AND NORTH LOOKS GOOD. THERE IS SOME CONCERN ON WHETHER OR NOT THE
REST OF THE PLAINS NEED SOME SORT OF HIGHLIGHT...BUT GUT FEELING IS
THAT THESE AREAS...THOUGH THEY WILL GET WINDY...WILL NOT REACH HIGH
WIND CRITERIA IN A WIDE ENOUGH AREA. AS FOR TEMPS AND PCPN
CHANCES...A RELATIVELY MILD NIGHT DUE TO THE INCREASING WINDS SHOULD
GIVE A BOOST TO MAX TEMPS TODAY...AND TEMPS IN THE 50S WITH 40S FOR
THE HIGH VALLEYS IS FORECAST. AS FOR PCPN...ONLY AREA THAT LOOKS
LIKE IT WILL RECEIVE ANY SIGNIFICANT PCPN WILL BE THE CENT MTS AS
THE W-NW FLOW ALOFT IS FAVORABLE FOR THAT AREA. LATEST MODELS
CONTINUE TO PAINT AROUND ONE INCH OF SNOW POSSIBLE THROUGH THE DAY.
FINALLY...AREAS OF BLOWING SNOW WILL BE A HAZARD OVER THE HIGHER MTN
PASSES THIS MORNING AND TODAY.
TONIGHT...AS THE UPPER DISTURBANCE PASSES TO THE EAST...THE SFC COLD
FRONT DROPS DOWN THE E PLAINS SOME TIME AROUND 00Z. AS WINDS DIE
DOWN...CLEARING SKIES AND COLD AIR FILTERING IN WILL SET THE STAGE
FOR A COLD NIGHT WITH MIN TEMPS IN THE TEENS AND SINGLE DIGITS...AND
BELOW ZERO FOR PORTIONS OF THE SLV. 27
LONG TERM...
.JANUARY THAW...
NOT MUCH SIGNIFICANT WEATHER IS ANTICIPATED DURING THIS PERIOD. A
LARGE RIDGE OF HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION
STARTING MONDAY AND LAST THROUGH LATE WEEK. A WEAK DISTURBANCE
WILL MOVE THROUGH THE RIDGE DURING THE TUESDAY TIME FRAME BUT THIS
FEATURE IS RATHER WEAK AND NO SENSIBLE WX IS EXPECTED WITH IT.
MAX TEMPERATURES FCSTED ATTM THROUGH MOST OF THE WEEK OVER THE
PLAINS WILL BE 50S TO AROUND 60F...BUT THESE NUMBERS WILL LIKELY
NEED TO BE ADJUSTED UPWARDS...ESPECIALLY ON THURSDAY AS 700 MB
TEMPS ARE FCST TO BE IN THE +8 RANGE (WHICH WOULD EQUAL TEMPS
AROUND 70F IF WE MIX DOWN DRY ADIABATICALLY).
BY LATE IN THE WEEK A MORE AMPLIFIED PAC TROUGH IS FCST TO MOVE
INTO THE REGION. ATTM THE BEST CHANCE OF PRECIP OVER THE AREA
WOULD BE LATE FRIDAY INTO EARLY SATURDAY. TEMPS SHOULD COOL DOWN
FOR NEXT WEEKEND. /34
AVIATION...
VFR CONDITIONS FOR THE NEXT 24 HRS EXPECTED FOR KALS. FOR KCOS AND
KPUB...THE MAIN CONCERN WILL BE STRONG W-NW WINDS DEVELOPING THIS
MORNING AND LASTING THROUGH 22Z. WILL MAINTAIN MENTION OF WIND SHEAR
FOR KCOS EARLY THIS MORNING THROUGH 14Z OR SO...BEFORE THE STRONGER
WINDS ALOFT MAKE IT DOWN TO THE SFC. WIND SHEAR DOES NOT LOOK TO BE
AN ISSUE FOR KPUB. GUSTS OF 45-50 KTS WILL BE POSSIBLE AT BOTH
SITES...AND ALONG THE I25 CORRIDOR...THROUGH THE MORNING AND EARLY
AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ058-
060>063-066-068-072>089-093>099.
&&
$$
31/77
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
953 AM MST SAT DEC 31 2011
.UPDATE...
IMPRESSIVE 8+ MB 3 HR PRESSURE RISES SWINGING THROUGH NORTHWEST CO
ATTM BEHIND UPPER TROF. WINDS HAVE BEEN GUSTING OVER 90 KTS AT
KMYP...WITH SALIDA AND BUENA VISTA AIRPORTS SEEING GUSTS TO 55
KTS. UPPER TROF IN WV AND LATEST MODEL RUNS IS CERTAINLY MORE AMPLIFIED
THAN RUNS FROM YESTERDAY...AND LATEST LOCAL 4KM WRF AND 12Z NAM12
SHOWING A WIDESPREAD SWATH OF 50-65 KT WINDS AT 800 MB SPREADING
ACROSS THE SOUTHEAST PLAINS. STRONG DOWNWARD FORCING AND MIXING
SHOULD BE SUFFICIENT TO TAP THESE WINDS ALOFT...RESULTING IN WIND
GUST POTENTIAL OF 65 MPH ACROSS THE PLAINS...PERHAPS STRONGER IN
SOME LOCATIONS. WINDS IN THE SAN LUIS VALLEY HAVE ALSO BEEN MUCH
STRONGER THAN MODELS PREDICTED...AND MTN TOP WINDS ACROSS THE SAN
JUANS AND LA GARITAS ARE EXPECTED TO INCREASE TO AROUND 70 KTS AT
PEAK LEVEL SHORTLY. THUS...HAVE EXPANDED HIGH WIND WARNINGS TO
INCLUDE THE REMAINDER OF THE SOUTHEAST PLAINS...AS WELL AS THE
HIGHER AREAS OF THE EASTERN SAN JUANS AND LA GARITAS. ITS POSSIBLE
THAT SOME OF THESE STRONG GUSTS MAY DESCEND INTO THE VALLEY EDGES
AND NECESSITATE FURTHER EXPANSION OF THE WARNINGS. WILL CONTINUE TO
MONITOR CLOSELY. -KT
&&
.PREV DISCUSSION... /ISSUED 333 AM MST SAT DEC 31 2011/
SHORT TERM...
(TODAY AND TONIGHT)
..STRONG WINDS EXPECTED ACROSS THE CENTRAL AND EASTERN
MOUNTAINS...NORTHERN I-25 CORRIDOR...AND NRN PORTIONS OF THE
SOUTHEAST PLAINS TODAY...
CURRENTLY...IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS CLEARLY
SHOWS THE APPROACHING SHORTWAVE CROSSING THE GREAT BASIN AND
NORTHERN ROCKIES THIS AM...WITH THE TROF AXIS ROUGHLY OVER ID AND W
MT AS OF 3 AM. SLC SFC OBS HAVE REPORTED HEFTY PRESSURE
RISES...WHILE CLOSER TO HOME WINDS HAVE BEEN ON THE INCREASE ACROSS
THE HIGHER ELEVATIONS. THE SENSOR ON PIKES PEAK REPORTED AN 84 MPH
GUSTS AT 1 AM...SO STRONG WINDS ARE COMING AS THE PRESSURE GRADIENT
TIGHTENS.
TODAY...THE UPPER JET THAT IS CARVING OUT THE BASE OF THIS SHORTWAVE
TROUGH HAS A CORE OF 100-110 KTS...AND IS EXPECTED TO SLIDE ACROSS
THE STATE TODAY. STRONGW-SW WINDS THIS MORNING WILL QUICKLY SHIFT TO
A NW DIRECTION AND STRENGTHEN THROUGH THE MORNING AS THE TROUGH
MOVES EAST...WITH BOTH THE NAM AND GFS MODELS INDICATING THAT THE
TROUGH AXIS WILL BE NEAR THE CO AND KS BORDER BY MIDDAY. MODEL CROSS
SECTIONS SHOW A RAPID INTENSIFICATION OF WINDS AS THEY DROP TOWARDS
THE SFC BETWEEN 12Z AND 18Z...AND GUSTS TO 60 MPH FOR THE LOWER
ELEVATIONS ARE PROBABLE THIS MORNING. HOW WIDESPREAD THESE GUSTS
WILL BE IS A QUESTION...BUT FEEL THAT MANY WILL EXPERIENCE HIGH
WINDS TODAY. THEREFORE...THE HIGH WIND WARNING ALREADY IN PLACE FOR
MUCH OF THE HIGHER TERRAIN...THE UPPER ARKANSAS RIVER VALLEY...MUCH
OF THE I25 CORRIDOR AND FOR PORTIONS OF THE PLAINS ALONG HIGHWAY 50
AND NORTH LOOKS GOOD. THERE IS SOME CONCERN ON WHETHER OR NOT THE
REST OF THE PLAINS NEED SOME SORT OF HIGHLIGHT...BUT GUT FEELING IS
THAT THESE AREAS...THOUGH THEY WILL GET WINDY...WILL NOT REACH HIGH
WIND CRITERIA IN A WIDE ENOUGH AREA. AS FOR TEMPS AND PCPN
CHANCES...A RELATIVELY MILD NIGHT DUE TO THE INCREASING WINDS SHOULD
GIVE A BOOST TO MAX TEMPS TODAY...AND TEMPS IN THE 50S WITH 40S FOR
THE HIGH VALLEYS IS FORECAST. AS FOR PCPN...ONLY AREA THAT LOOKS
LIKE IT WILL RECEIVE ANY SIGNIFICANT PCPN WILL BE THE CENT MTS AS
THE W-NW FLOW ALOFT IS FAVORABLE FOR THAT AREA. LATEST MODELS
CONTINUE TO PAINT AROUND ONE INCH OF SNOW POSSIBLE THROUGH THE DAY.
FINALLY...AREAS OF BLOWING SNOW WILL BE A HAZARD OVER THE HIGHER MTN
PASSES THIS MORNING AND TODAY.
TONIGHT...AS THE UPPER DISTURBANCE PASSES TO THE EAST...THE SFC COLD
FRONT DROPS DOWN THE E PLAINS SOME TIME AROUND 00Z. AS WINDS DIE
DOWN...CLEARING SKIES AND COLD AIR FILTERING IN WILL SET THE STAGE
FOR A COLD NIGHT WITH MIN TEMPS IN THE TEENS AND SINGLE DIGITS...AND
BELOW ZERO FOR PORTIONS OF THE SLV. 27
LONG TERM...
..JANUARY THAW...
NOT MUCH SIGNIFICANT WEATHER IS ANTICIPATED DURING THIS PERIOD. A
LARGE RIDGE OF HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION
STARTING MONDAY AND LAST THROUGH LATE WEEK. A WEAK DISTURBANCE
WILL MOVE THROUGH THE RIDGE DURING THE TUESDAY TIME FRAME BUT THIS
FEATURE IS RATHER WEAK AND NO SENSIBLE WX IS EXPECTED WITH IT.
MAX TEMPERATURES FCSTED ATTM THROUGH MOST OF THE WEEK OVER THE
PLAINS WILL BE 50S TO AROUND 60F...BUT THESE NUMBERS WILL LIKELY
NEED TO BE ADJUSTED UPWARDS...ESPECIALLY ON THURSDAY AS 700 MB
TEMPS ARE FCST TO BE IN THE +8 RANGE (WHICH WOULD EQUAL TEMPS
AROUND 70F IF WE MIX DOWN DRY ADIABATICALLY).
BY LATE IN THE WEEK A MORE AMPLIFIED PAC TROUGH IS FCST TO MOVE
INTO THE REGION. ATTM THE BEST CHANCE OF PRECIP OVER THE AREA
WOULD BE LATE FRIDAY INTO EARLY SATURDAY. TEMPS SHOULD COOL DOWN
FOR NEXT WEEKEND. /34
AVIATION...
VFR CONDITIONS FOR THE NEXT 24 HRS EXPECTED FOR KALS. FOR KCOS AND
KPUB...THE MAIN CONCERN WILL BE STRONG W-NW WINDS DEVELOPING THIS
MORNING AND LASTING THROUGH 22Z. WILL MAINTAIN MENTION OF WIND SHEAR
FOR KCOS EARLY THIS MORNING THROUGH 14Z OR SO...BEFORE THE STRONGER
WINDS ALOFT MAKE IT DOWN TO THE SFC. WIND SHEAR DOES NOT LOOK TO BE
AN ISSUE FOR KPUB. GUSTS OF 45-50 KTS WILL BE POSSIBLE AT BOTH
SITES...AND ALONG THE I25 CORRIDOR...THROUGH THE MORNING AND EARLY
AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ058-
060>063-066-068-072>089-093>099.
&&
$$
31/77
AREA FORECAST DISCUSSION
NWS PUEBLO CO
333 AM MST SAT DEC 31 2011
.SHORT TERM...
(TODAY AND TONIGHT)
...STRONG WINDS EXPECTED ACROSS THE CENTRAL AND EASTERN
MOUNTAINS...NORTHERN I-25 CORRIDOR...AND NRN PORTIONS OF THE
SOUTHEAST PLAINS TODAY...
CURRENTLY...IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS CLEARLY
SHOWS THE APPROACHING SHORTWAVE CROSSING THE GREAT BASIN AND
NORTHERN ROCKIES THIS AM...WITH THE TROF AXIS ROUGHLY OVER ID AND W
MT AS OF 3 AM. SLC SFC OBS HAVE REPORTED HEFTY PRESSURE
RISES...WHILE CLOSER TO HOME WINDS HAVE BEEN ON THE INCREASE ACROSS
THE HIGHER ELEVATIONS. THE SENSOR ON PIKES PEAK REPORTED AN 84 MPH
GUSTS AT 1 AM...SO STRONG WINDS ARE COMING AS THE PRESSURE GRADIENT
TIGHTENS.
TODAY...THE UPPER JET THAT IS CARVING OUT THE BASE OF THIS SHORTWAVE
TROUGH HAS A CORE OF 100-110 KTS...AND IS EXPECTED TO SLIDE ACROSS
THE STATE TODAY. STRONGW-SW WINDS THIS MORNING WILL QUICKLY SHIFT TO
A NW DIRECTION AND STRENGTHEN THROUGH THE MORNING AS THE TROUGH
MOVES EAST...WITH BOTH THE NAM AND GFS MODELS INDICATING THAT THE
TROUGH AXIS WILL BE NEAR THE CO AND KS BORDER BY MIDDAY. MODEL CROSS
SECTIONS SHOW A RAPID INTENSIFICATION OF WINDS AS THEY DROP TOWARDS
THE SFC BETWEEN 12Z AND 18Z...AND GUSTS TO 60 MPH FOR THE LOWER
ELEVATIONS ARE PROBABLE THIS MORNING. HOW WIDESPREAD THESE GUSTS
WILL BE IS A QUESTION...BUT FEEL THAT MANY WILL EXPERIENCE HIGH
WINDS TODAY. THEREFORE...THE HIGH WIND WARNING ALREADY IN PLACE FOR
MUCH OF THE HIGHER TERRAIN...THE UPPER ARKANSAS RIVER VALLEY...MUCH
OF THE I25 CORRIDOR AND FOR PORTIONS OF THE PLAINS ALONG HIGHWAY 50
AND NORTH LOOKS GOOD. THERE IS SOME CONCERN ON WHETHER OR NOT THE
REST OF THE PLAINS NEED SOME SORT OF HIGHLIGHT...BUT GUT FEELING IS
THAT THESE AREAS...THOUGH THEY WILL GET WINDY...WILL NOT REACH HIGH
WIND CRITERIA IN A WIDE ENOUGH AREA. AS FOR TEMPS AND PCPN
CHANCES...A RELATIVELY MILD NIGHT DUE TO THE INCREASING WINDS SHOULD
GIVE A BOOST TO MAX TEMPS TODAY...AND TEMPS IN THE 50S WITH 40S FOR
THE HIGH VALLEYS IS FORECAST. AS FOR PCPN...ONLY AREA THAT LOOKS
LIKE IT WILL RECEIVE ANY SIGNIFICANT PCPN WILL BE THE CENT MTS AS
THE W-NW FLOW ALOFT IS FAVORABLE FOR THAT AREA. LATEST MODELS
CONTINUE TO PAINT AROUND ONE INCH OF SNOW POSSIBLE THROUGH THE DAY.
FINALLY...AREAS OF BLOWING SNOW WILL BE A HAZARD OVER THE HIGHER MTN
PASSES THIS MORNING AND TODAY.
TONIGHT...AS THE UPPER DISTURBANCE PASSES TO THE EAST...THE SFC COLD
FRONT DROPS DOWN THE E PLAINS SOME TIME AROUND 00Z. AS WINDS DIE
DOWN...CLEARING SKIES AND COLD AIR FILTERING IN WILL SET THE STAGE
FOR A COLD NIGHT WITH MIN TEMPS IN THE TEENS AND SINGLE DIGITS...AND
BELOW ZERO FOR PORTIONS OF THE SLV. MOORE
.LONG TERM...
...JANUARY THAW...
NOT MUCH SIGNIFICANT WEATHER IS ANTICIPATED DURING THIS PERIOD. A
LARGE RIDGE OF HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION
STARTING MONDAY AND LAST THROUGH LATE WEEK. A WEAK DISTURBANCE
WILL MOVE THROUGH THE RIDGE DURING THE TUESDAY TIME FRAME BUT THIS
FEATURE IS RATHER WEAK AND NO SENSIBLE WX IS EXPECTED WITH IT.
MAX TEMPERATURES FCSTED ATTM THROUGH MOST OF THE WEEK OVER THE
PLAINS WILL BE 50S TO AROUND 60F...BUT THESE NUMBERS WILL LIKELY
NEED TO BE ADJUSTED UPWARDS...ESPECIALLY ON THURSDAY AS 700 MB
TEMPS ARE FCST TO BE IN THE +8 RANGE (WHICH WOULD EQUAL TEMPS
AROUND 70F IF WE MIX DOWN DRY ADIABATICALLY).
BY LATE IN THE WEEK A MORE AMPLIFIED PAC TROUGH IS FCST TO MOVE
INTO THE REGION. ATTM THE BEST CHANCE OF PRECIP OVER THE AREA
WOULD BE LATE FRIDAY INTO EARLY SATURDAY. TEMPS SHOULD COOL DOWN
FOR NEXT WEEKEND. /HODANISH
&&
.AVIATION...
VFR CONDITIONS FOR THE NEXT 24 HRS EXPECTED FOR KALS. FOR KCOS AND
KPUB...THE MAIN CONCERN WILL BE STRONG W-NW WINDS DEVELOPING THIS
MORNING AND LASTING THROUGH 22Z. WILL MAINTAIN MENTION OF WIND SHEAR
FOR KCOS EARLY THIS MORNING THROUGH 14Z OR SO...BEFORE THE STRONGER
WINDS ALOFT MAKE IT DOWN TO THE SFC. WIND SHEAR DOES NOT LOOK TO BE
AN ISSUE FOR KPUB. GUSTS OF 45-50 KTS WILL BE POSSIBLE AT BOTH
SITES...AND ALONG THE I25 CORRIDOR...THROUGH THE MORNING AND EARLY
AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ061-062-
077-078-083>087-089-095-096.
HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ058-060-
063-072-073-075-076-079>082.
&&
$$
27/34
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
355 PM EST Sat Dec 31 2011
.SYNOPSIS...
20Z water vapor and H4 RUC analysis shows an amplified but
progressive northern stream flow pattern across North America.
Pattern currently consists of troughs over the Northeastern states
and also digging through the northern Plains/Upper MS valley.
Between these features we find ridging over the Great Lakes region,
and also building over the Pacific Northwest. The flow pattern
across the southern tier of the CONUS/northern Gulf coast takes on
a more zonal configuration. Pleasant afternoon ongoing across the
forecast area after the dense morning fog.
At the surface, a weak front is analyzed just to the north of the
I-10 corridor and is essentially washing out this afternoon/evening.
South of this front a ridge of high pressure extends across the FL
peninsula and into the NE Gulf of Mexico. Temperatures are quite
enjoyable out there for the last day of December, with many
locations reaching the lower to middle 70s. Temperatures along the
immediate coast are being held in the 60s with light onshore flow
off the relatively cooler shelf waters.
&&
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
Tonight,
Main concern will be dealing with the potential for areas of dense
fog development later this evening and into the early morning hours
of Sunday. Setup for fog seems quite good with subtle moisture
advection from the south underneath abundant dry air above the
surface. High-resolution and statistic guidance are in fair
agreement in the fog development commencing later this evening along
and south of the I-10 corridor, and then expanding quickly
northward. Evening/overnight shifts will need to monitor the
situation in case dense fog advisories become necessary for portions
of the area. Outside of the development fog, the forecast will be
dry and quiet for any outdoor first night festivities. Temperatures
will generally bottom out in the lower to middle 50s.
Sunday,
Overall upper level pattern will further amplify as the trough over
the mid-section of the county moves east and begins to phase with
additional shortwave energy from the north. A weak cold front ahead
of this feature will move into our western zones by early afternoon
and then pass east of our area Sunday evening. Expecting Sunday to
start out with areas/widespread fog across the eastern zones. Due to
the weak sun angle, the fog will likely linger through much of the
morning. Forecast is a bit trickier further west toward Panama City
and Dothan in closer proximity to the approaching front. Will clear
the dense fog out of these western zones a few hours earlier as a
gradient tightens and promotes more efficient mixing during the
morning hours. Will keep PoPs around 10% with this frontal passage
as the overall column moisture and synoptic forcing is not
impressive. Will add sct sprinkles to the grids as most guidance
members are showing some light QPF. Doubt most areas will see
measurable precip, but a few raindrops can not be ruled out.
Sunday night,
A drier and noticeably cooler airmass (although not unusual) will
filter in during the night behind Sunday`s front. Skies will be
clearing with a steady NW breeze. Still not expecting any freezing
temperatures as low temps will range from the middle 30s north of
Dothan and Albany to the lower 40s south and east of Tallahassee and
Valdosta.
Monday/Monday night,
A significant amplification to the upper level pattern will occur
during the daylight hours with an impressive trough across the
eastern third of the nation by the end of the day. This
amplification will be accompanied by a strong surge of arctic air
into the eastern states. This stronger more arctic configuration
front is not scheduled to arrive until Monday evening. Therefore,
much of our area will reside within the thermal ridge ahead of the
front Monday afternoon, with temperatures climbing into the middle
and upper 50s. The big change will occur Monday evening as the
arctic front quickly passes through. As of the 12Z guidance cycle,
the ECMWF/Canadian and UKMET all show 850mb temps down between -8
and -10C around KTLH and -12C up toward Albany and Tifton by
sunrise. The GFS remains an outlier on the warm side, with 850mb
temps over the CWA up to 10C warmer than the other global guidance
members. Going to side with the colder guidance consensus, which is
also in agreement with HPC. The resulting forecast will show a
widespread advection freeze Monday night. A steady northwest wind
will add to the cold with windchill values down into the upper
teens by sunrise.
&&
.LONG TERM (TUESDAY MORNING THROUGH NEXT SATURDAY)...
The main surge of arctic air will advect into our forecast area by
early Tuesday. While all of the numerical guidance shows a deep
long wave 500 mb trough over the eastern U.S. and a strong arctic
surface high diving southward into the Southern Plains, the
solutions differ as to just how cold it will be here. The NAM,
ECMWF, and CMC are very cold with an 850 mb temperature around -9
deg C at Tallahassee early Tuesday. The outlier GFS is a good 10 deg
C warmer than this. The GFS may be correct, but it seems prudent at
this point to average the colder solutions into our forecast so that
we don`t miss too badly if the GFS is too warm. Despite the winds
remaining in the 5-10 MPH range most of Monday night, lows will
likely fall well below freezing over our entire forecast area (even
at the beaches). We may meet our local wind chill advisory criteria
for the first time this season. Even if the warmer GFS verifies, GFS
BUFKIT soundings indicate highs will struggle to reach the mid 40s,
which is several degrees colder than the GFS MOS. All the global NWP
guidance continues to forecast the arctic surface high to become
centered over Tallahassee Wednesday morning. This will allow the
winds to become calm overnight. With calm winds, dewpoints around 10
degrees, and one of the longest nights of the year, we think low
temperatures will plummet more than what the GFS MOS is currently
forecasting (mid 20s). Near-record lows in the upper teens seem more
likely given such a favorable cooling setup, with mid to upper 20s
at the coast and in the larger cities.
We looked back at two of the coldest recent arctic outbreaks here
(that occurred without snow) and found some similarities to this
forecast. The two that we examined where the January 1985 and
December 1983 outbreaks, both of which set records locally. Early
indications are that this upcoming outbreak will not be quite as bad
given that the surface high may be slightly weaker, and the 850 mb
cold pool is not expected to be quite as expansive as was observed
in the previous cases. However, we will continue to monitor
subsequent model trends as these short-lived arctic outbreaks can
produce surprisingly cold temperatures in the Deep South, even when
the winds are not calm.
A slow warming trend will begin Wednesday afternoon, though the GFS
MOS appears to be bouncing back toward climatology too quickly, and
we plan to slow this warming down a bit. In fact, the surface high
will still be in a favorable position for another freeze Thursday
morning, but a weak upper level trough passing by may bring enough
upper level moisture to counteract the boundary layer cooling.
The 00 UTC GFS and ECMWF forecast a weak cold front west-northwest
of our forecast area by Saturday. The GFS solution is more
progressive while the ECMWF appears to stall the front too far away
for any rain for our area. Given how far out this and the recent
inconsistencies in the GFS for this time frame, we will leave out
any mention of PoP above 10 percent. Milder temperatures will return
Friday and Saturday.
&&
.AVIATION (Through 18Z UTC Sunday)...
Dense fog is expected to blanket the area tomorrow morning with
visibilities down to 1/4 SM. A weak cold front will begin to
approach Southeast Alabama and the western Florida Panhandle on
Sunday helping to mix out the fog by mid morning at KDHN
and KECP. Timing is everything so we feel lowered CIGS and VSBYs
will drag into late morning at KABY, KTLH and KVLD.
&&
.MARINE...
A surface ridge of high pressure over the northeast Gulf of Mexico
will keep winds and seas low through tonight. A cold front will then
cross the forecast waters Sunday and Sunday evening. Winds will
shift northerly in the wake of this front and quickly increase to
advisory levels. A secondary cold front will then cross the forecast
waters Monday evening helping to keep winds and seas elevated to
advisory levels. The current forecast will reflect a pattern more in
line with the ECMWF/Canadian/UKMET consensus solutions. These
guidance members bring a stronger push of cold air advection
compared to the outlier GFS solution. Therefore, wind gusts are
forecast to approach gale force at times Monday night, especially
over the offshore legs. Winds and seas will then quickly decrease
Tuesday night into Wednesday as another ridge of high pressure
builds over the region.
&&
.FIRE WEATHER...
Red Flag conditions are unlikely through Sunday. However, very dry
air will increase the threat for Red Flag conditions on Monday and
Tuesday as cold, very dry air moves into the region on gusty
northwest winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 50 75 40 57 25 / 0 10 10 0 0
Panama City 58 74 42 56 29 / 0 10 0 0 0
Dothan 53 72 37 54 25 / 10 10 0 0 0
Albany 49 72 36 53 25 / 10 10 0 0 0
Valdosta 48 74 39 54 25 / 0 10 10 0 0
Cross City 47 74 43 58 26 / 0 0 10 0 0
Apalachicola 56 71 41 57 29 / 0 10 10 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM...FOURNIER
AVIATION/FIRE WEATHER...LANIER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
158 PM CST SAT DEC 31 2011
.DISCUSSION...
ISSUED 158 PM CST SAT DEC 31 2011
GUSTY/MILD WINDS ARE DEVELOPING ACROSS CENTRAL AND SOUTHEAST
ILLINOIS THIS AFTERNOON AHEAD OF A STRENGTHENING STORM SYSTEM IN
THE PLAINS. WINDS WILL SWING AROUND TO THE WEST BY LATE TONIGHT AS
A STRONG COLD FRONT PUSHES THROUGH THE AREA. THESE WINDS WILL
TRANSPORT MUCH COLDER AIR INTO THE AREA FOR THE BEGINNING OF THE
WEEK...WITH GUSTS AROUND 45 MPH LIKELY FROM FRONTAL PASSAGE INTO
SUNDAY EVENING. MAIN FORECAST CONCERNS TODAY REVOLVE AROUND HOW
STRONG THE WINDS WILL BE ON EITHER SIDE OF THE FRONT FOR THE NEXT
24 HOURS...AS WELL AS PRECIPITATION CHANCES WITH FRONTAL PASSAGE.
12Z MODELS CONTINUE TO BE IN GOOD OVERALL AGREEMENT FOR THE NEXT
SEVERAL DAYS. AFTER THE WINDS DIE DOWN BY LATER MONDAY...THE
BALANCE OF THE FORECAST PERIOD SHOULD FEATURE BENIGN WEATHER.
SHORT TERM...TONIGHT THROUGH TUESDAY...A DEEPENING AREA OF LOW
PRESSURE WILL TRACK FROM THE NEBRASKA/IOWA BORDER AREA THIS
AFTERNOON INTO NORTHEAST ONTARIO SUNDAY EVENING. AS THIS LOW
PASSES TO THE NORTH OF THE FORECAST AREA OVERNIGHT...IT WILL DRAG
A STRONG COLD FRONT THROUGH THE AREA. WINDS ARE EXPECTED TO BECOME
QUITE STRONG OUT OF THE WEST NORTHWEST IN THE WAKE OF THE
FRONT...WITH GUSTS OF AT LEAST 45 MPH COMMON FROM FROPA INTO
SUNDAY EVENING. WIND GUSTS MAY BE EVEN STRONGER IN NORTHERN
SECTIONS OF THE FORECAST AREA LATE TONIGHT THROUGH MIDDAY SUNDAY
AS FORECAST SOUNDINGS SUGGEST EVEN MORE IMPRESSIVE DOWNWARD
MOMENTUM TRANSFER IN THIS AREA...AND THIS AREA IS CLOSER TO THE
STRONG 8 MB/3 HOUR SURFACE PRESSURE FALL/RISE COUPLET THAT APPEARS
LIKELY TO TRACK ALONG THE I-80 CORRIDOR. HAVE POSTED A WIND
ADVISORY FROM MIDNIGHT TONIGHT INTO MIDNIGHT SUNDAY TO HIGHLIGHT
THE STRONG WIND POTENTIAL. CAN NOT RULE OUT THE POTENTIAL FOR A
FEW COUNTIES NEEDING TO BE UPGRADED TO A HIGH WIND WARNING...BUT
THIS POTENTIAL IS HIGHER NORTH/WEST OF CENTRAL ILLINOIS.
THERE IS ONLY A LIMITED RISK OF PRECIPITATION WITH THE PASSAGE OF
THIS STORM SYSTEM. THE BULK OF THE FORECAST AREA WILL HAVE TOO
SHALLOW OF A MOISTURE DEPTH TO SUPPORT PRECIPITATION
DEVELOPMENT. HOWEVER...LOCATIONS ROUGHLY ALONG AND NORTH OF A
RUSHVILLE TO BLOOMINGTON LINE STAND THE BEST CHANCE TO GET BRUSHED
BY THE WRAP AROUND CLOUD/PRECIP SHIELD TONIGHT AS THE LOW PASSES
BY. THIS RISK SHOULD END BY SUNRISE...AND ANY PRECIPITATION THAT
DOES FALL IS EXPECTED TO BE MINIMAL.
WHILE WINDS WILL FALL BELOW ADVISORY CRITERIA SUNDAY EVENING...A
STRONG PRESSURE GRADIENT SUPPORTS WINDS STAYING ON THE GUSTY SIDE
THROUGH MONDAY. THE PERIOD OF MONDAY THROUGH TUESDAY ALSO STANDS
TO BE THE COLDEST OF THE WINTER SEASON THUS FAR...THOUGH
TEMPERATURES WILL STILL ONLY BE A FEW DEGREES COLDER THAN NORMAL.
LONG TERM...WEDNESDAY THROUGH SATURDAY...A CLIPPER SYSTEM IS
PROGGED TO PASS TO OUR NORTH ON WEDNESDAY AND IS NOT EXPECTED TO
BE A PRECIPITATION RISK LOCALLY. THEN...WITH SURFACE RIDGING
PUSHING OFF TO THE EAST AND UPPER RIDGING BUILDING OVERHEAD FOR
THE REST OF THE PERIOD...QUIET WEATHER AND A RETURN TO
UNSEASONABLY MILD CONDITIONS IS ANTICIPATED.
BAK
&&
.AVIATION...
ISSUED 1125 AM CST SAT DEC 31 2011
MVFR STRATUS DECK STILL LINGERING OVER THE NORTHEAST HALF OF
ILLINOIS...WITH SOME DIURNAL REDEVELOPMENT ON THE WESTERN FLANK
FROM KGBG-KTMO. WILL LIKELY SEE THIS BREAK UP BY ABOUT 21Z AT
KPIA/KDEC/KBMI...BUT AM NOT TERRIBLY OPTIMISTIC FURTHER EAST
AFTER LOOKING AT RUC FORECAST SOUNDINGS.
MAIN PROBLEM MUCH OF THE PERIOD WILL BE WITH THE WINDS. SOUTHERLY
WINDS TO CRANK UP THIS EVENING AHEAD OF A RAPIDLY INTENSIFYING LOW
ACROSS IOWA. WILL BEGIN SEEING THE WINDS SWITCHING WESTERLY
BETWEEN 06-12Z AS THE LOW PASSES TO OUR NORTH. VERY STRONG
PRESSURE RISES BEHIND THE LOW WILL RESULT IN 35-40 KNOT GUSTS IN
MANY AREAS THROUGH ABOUT MID AFTERNOON...WITH SOME POTENTIAL FOR
HIGHER THAN 45 KNOTS BASED ON LOW LEVEL SOUNDING DATA. ANOTHER
SURGE OF MVFR CEILINGS IS EXPECTED AFTER 06Z AS THE LOW GOES BY.
WESTERN TAF SITES WILL PROBABLY SEE CEILINGS SCATTER OUT BY ABOUT
14-15Z...BUT AREAS NEAR KCMI WILL LIKELY REMAIN IN MVFR CONDITIONS
UNTIL CLOSER TO MIDDAY.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT
FOR ILZ027>031-036>038-040>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1125 AM CST SAT DEC 31 2011
.DISCUSSION...
ISSUED 1005 AM CST SAT DEC 31 2011
BACK EDGE OF THE STRATUS DECK EXTENDING FROM ABOUT MOLINE...TO
DECATUR...TO OLNEY. AWIPS TIME-OF-ARRIVAL TOOL INDICATING THE
CLEARING SHOULD REACH CHAMPAIGN AROUND 11 AM AND BY OUT OF THE CWA
BY ABOUT 1230 PM. STILL EXPECTING TO SEE THE WINDS PICK UP THIS
AFTERNOON AS 30-35 KNOT WINDS AT 925 MB START MIXING TOWARD THE
SURFACE. HAVE SENT SOME UPDATED ZONES/GRIDS TO REFLECT THE LATEST
CLEARING TRENDS. WINDS AND TEMPERATURES LOOKED FAIRLY GOOD SO
LITTLE CHANGE WAS MADE THERE.
WATER VAPOR IMAGERY SHOWING UPPER TROUGH DIGGING ACROSS WYOMING
AND COLORADO LATE THIS MORNING. THIS WILL SOON BE INTERACTING WITH
A COLD FRONT EXTENDING FROM SOUTH DAKOTA TO WESTERN KANSAS...AND
RAPIDLY INTENSIFY A SURFACE LOW CURRENTLY OVER NEBRASKA. EARLY
LOOK AT 12Z MODELS REMAIN QUITE IMPRESSIVE WITH THIS SYSTEM...WITH
3 HOUR PRESSURE RISES ON THE ORDER OF 7 TO 9 MB EXPECTED FROM LATE
TONIGHT THROUGH MIDDAY SUNDAY BEHIND THE LOW. HIGH-RESOLUTION
LOCAL MODELS SHOWING STRONG WINDS MOVING INTO THE WESTERN CWA
BETWEEN 2 AND 6 AM...AND ACROSS THE REMAINDER OF THE CWA EARLY
SUNDAY MORNING...WITH THE CHICAGO WRF AND NAM-DNG MODELS SHOWING
SOME POTENTIAL IN EXCESS OF 50 MPH. WIND HEADLINES WILL BE
FORTHCOMING IN THE NEXT FEW HOURS...BUT WILL BE COORDINATING WITH
NEIGHBORING AREAS TO DETERMINE ADVISORY VS WARNING POTENTIAL.
GEELHART
&&
.AVIATION...
ISSUED 1125 AM CST SAT DEC 31 2011
MVFR STRATUS DECK STILL LINGERING OVER THE NORTHEAST HALF OF
ILLINOIS...WITH SOME DIURNAL REDEVELOPMENT ON THE WESTERN FLANK
FROM KGBG-KTMO. WILL LIKELY SEE THIS BREAK UP BY ABOUT 21Z AT
KPIA/KDEC/KBMI...BUT AM NOT TERRIBLY OPTIMISTIC FURTHER EAST
AFTER LOOKING AT RUC FORECAST SOUNDINGS.
MAIN PROBLEM MUCH OF THE PERIOD WILL BE WITH THE WINDS. SOUTHERLY
WINDS TO CRANK UP THIS EVENING AHEAD OF A RAPIDLY INTENSIFYING LOW
ACROSS IOWA. WILL BEGIN SEEING THE WINDS SWITCHING WESTERLY
BETWEEN 06-12Z AS THE LOW PASSES TO OUR NORTH. VERY STRONG
PRESSURE RISES BEHIND THE LOW WILL RESULT IN 35-40 KNOT GUSTS IN
MANY AREAS THROUGH ABOUT MID AFTERNOON...WITH SOME POTENTIAL FOR
HIGHER THAN 45 KNOTS BASED ON LOW LEVEL SOUNDING DATA. ANOTHER
SURGE OF MVFR CEILINGS IS EXPECTED AFTER 06Z AS THE LOW GOES BY.
WESTERN TAF SITES WILL PROBABLY SEE CEILINGS SCATTER OUT BY ABOUT
14-15Z...BUT AREAS NEAR KCMI WILL LIKELY REMAIN IN MVFR CONDITIONS
UNTIL CLOSER TO MIDDAY.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 246 AM CST SAT DEC 31 2011
ONE MORE MILD DAY EXPECTED...BEFORE WINDY AND SHARPLY COLDER
CONDITIONS ARRIVE EARLY NEXT WEEK.
SHORT TERM...TODAY THROUGH SUNDAY
08Z SATELLITE IMAGERY SHOWS OVERCAST CONDITIONS ACROSS CENTRAL
ILLINOIS...WITH CLOUD COVER PERSISTING WELL UPSTREAM INTO IOWA AND
MINNESOTA AS WELL. LARGE BREAK IN THE CLOUDS OVER WISCONSIN
AND NORTHERN ILLINOIS WILL GENERALLY WORK ITS WAY E/SE THROUGH THE
CHICAGO AREA INTO NORTHWEST INDIANA...WHILE PREVAILING NORTHWESTERLY
LOW-LEVEL FLOW WILL KEEP CLOUD COVER IN PLACE ACROSS CENTRAL
ILLINOIS THROUGH MID-MORNING. NAM 925MB RH FIELD SHOWS MOISTURE
GRADUALLY DISSIPATING TOWARD MIDDAY...RESULTING IN CLEARING SKIES.
MOSTLY SUNNY AND UNSEASONABLY WARM CONDITIONS WILL PREVAIL THIS
AFTERNOON...AS BRISK SOUTHERLY WINDS DEVELOP IN ADVANCE OF THE
NEXT APPROACHING SYSTEM. TIGHTENING PRESSURE GRADIENT AND FORECAST
SOUNDINGS SUGGEST WIND GUSTS UP TO 30 MPH ACROSS THE WESTERN HALF
OF THE KILX CWA. THANKS TO THE AMPLE SUNSHINE AND STEADY SOUTHERLY
FLOW...HIGH TEMPERATURES WILL TOP THE 50 DEGREE MARK IN MOST LOCATIONS.
AMPLIFYING SHORT-WAVE WILL PUSH A STRONG COLD FRONT THROUGH
CENTRAL ILLINOIS TONIGHT...ACCOMPANIED BY CLOUDS AND PERHAPS A FEW
SCATTERED SHOWERS. DUE TO LIMITED MOISTURE RETURN FROM THE
GULF...WILL ONLY CARRY SLIGHT CHANCE POPS WITH FROPA...MAINLY
ACROSS THE NORTHERN CWA IN CLOSER PROXIMITY TO STRONGEST UPPER
DYNAMICS. ONCE THE FRONT PASSES...VERY WINDY CONDITIONS WILL
DEVELOP ON SUNDAY AS STRONG COLD ADVECTION COMES IN. TIGHT PRESSURE
GRADIENT AND SCREAMING LOW-LEVEL WINDS...SUGGEST GUSTS COULD REACH
40 MPH OR GREATER AT TIMES. HIGH TEMPS WILL STRUGGLE TO RISE MUCH
FROM EARLY MORNING LOWS...WITH READINGS ONLY REACHING THE UPPER
30S AND LOWER 40S.
LONG TERM...MONDAY THROUGH FRIDAY
A BRIEF SHOT OF COLD AIR WILL INVADE THE MIDWEST EARLY NEXT
WEEK...AS DEEP UPPER TROUGH DIGS ACROSS THE EASTERN CONUS. ECMWF
AND GFS ARE NOW QUITE SIMILAR WITH THEIR THERMAL PROFILES...WITH
BOTH MODELS INDICATING HIGH TEMPS ONLY IN THE UPPER 20S AND LOWER
30S FOR BOTH MONDAY AND TUESDAY. COLDEST MORNING OF THE FORECAST
PERIOD WILL BE TUESDAY MORNING...WHEN HIGH PRESSURE RIDGE BUILDING
IN FROM THE WEST WILL ALLOW LOW TEMPS TO BOTTOM OUT IN THE TEENS.
AFTER THAT...BOTH MODELS CONTINUE TO ADVERTISE A QUICK RETURN TO
ABOVE NORMAL TEMPS BY THE END OF THE WEEK AS THE TROUGH DEPARTS
AND W/SW FLOW RETURNS. HAVE BOOSTED HIGH TEMPS BACK INTO THE 40S
BY THURSDAY...WITH EVEN WARMER READINGS IN THE 50S BY FRIDAY.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
333 AM EST MON JAN 2 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM EXITING THE GREAT LAKES TONIGHT TO THE
NORTHEAST AND STRONG CANADIAN HIGH PRESSURE BUILDING INTO THE PLAINS
WILL KEEP GUSTY WINDS OVER THE AREA THROUGH MONDAY EVENING.
NORTHERLY AND NORTHWESTERLY WINDS OFF LAKE MICHIGAN WILL KEEP LOW
CHANCES FOR LAKE EFFECT SNOW SHOWERS OVER THE NORTHEAST COUNTIES
MONDAY INTO TUESDAY. A BROAD RIDGE OF HIGH PRESSURE WILL THEN
DOMINATE THE WEATHER THROUGH THE REMAINDER OF THE PERIOD AND KEEP
DRY WEATHER IN PLACE. TEMPERATURES WILL DROP BELOW NORMAL FOR THE
BEGINNING OF THE WORK WEEK BUT REBOUND TO NEAR NORMAL BY WEDNESDAY
AND ABOVE NORMAL ON THURSDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
WILL UPDATE SHORTLY TO END THE WIND ADVISORY AND ADD SLIGHT CHANCE
SNOW SHOWERS TO MUCH OF THE AREA.
UPSTREAM WIND GUSTS ARE GENERALLY BELOW CRITERIA AS EXPECTED...AND
OURS HAVE BEEN SLOWLY RELAXING AS WELL. GUSTS TO 35-40 MPH WILL
CONTINUE OVERNIGHT...REMAINING JUST BELOW CRITERIA AT THEIR PEAK.
BROAD AREA OF LIGHT RADAR RETURNS OVER THE REGION...WITH SOME OF
THEM OCCASIONALLY MAKING THE GROUND. WEBCAMS INDICATE A LIGHT
DUSTING IN THE MUNCIE AREA. RUC SOUNDINGS SUGGEST SNOW GROWTH
LAYER SLOWLY MOISTENING OVERNIGHT AS A SECONDARY SHORTWAVE SPINS
AROUND THE BACK SIDE OF THE UPPER TROUGH. THUS...FEEL THAT AT
LEAST A SLIGHT CHANCE OF SNOW SHOWERS IS NECESSARY. NO
ACCUMULATIONS BEYOND A VERY LIGHT DUSTING POSSIBLE...AS DRY AIR
NEAR THE SURFACE WILL BE SUBLIMATING MUCH OF THE SNOW AS IT FALLS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
FORECAST FOCUS IS ON WIND GUSTS MONDAY AND CHANCES FOR SNOW SHOWERS
WITH LAKE EFFECT IN THE WAKE OF THE COLD FRONT. MODELS ARE IN GOOD
AGREEMENT AND WILL USE A CONSENSUS APPROACH.
A TIGHT PRESSURE GRADIENT WILL CONTINUE TO BE IN PLACE MONDAY AS
INDIANA IS BETWEEN STRONG HIGH AND LOW PRESSURE SYSTEMS. THIS WILL
ALLOW SUSTAINED WINDS AROUND 20-25 MPH AND GUSTS OF 30-40 MPH TO
PERSIST THROUGH THE DAY UNTIL THE GRADIENT FINALLY BEGINS TO SLACKEN
MONDAY NIGHT AS THE STRONG LOW FINALLY EXITS UP THE EASTERN CANADIAN
SEABOARD AND HIGH PRESSURE MOVES CLOSER TO INDIANA. AT THIS TIME
FORECAST SOUNDINGS ARE NOT SHOWING WINDS QUITE AS STRONG AS TODAY SO
IT DOES NOT APPEAR THAT ANOTHER ADVISORY WILL BE NECESSARY.
A WEAK IMPULSE WILL MOVE THROUGH THE AREA TOMORROW ON THE BACK SIDE
OF THE LOW...AND THIS EXTRA BIT OF FORCING ALONG WITH 850 MB WINDS
BECOMING NORTH NORTHWESTERLY COULD ALLOW A FEW SNOW SHOWERS TO FORM
ACROSS NORTHEASTERN PARTS OF THE AREA MONDAY AFTERNOON. THESE WINDS
WILL CONTINUE TO PROVIDE A GOOD FETCH ACROSS LAKE MICHIGAN TO
PRODUCE THE POTENTIAL FOR SOME LAKE EFFECT SNOW STRETCHING INTO THE
NORTHEASTERN COUNTIES THROUGH THE MORNING ON TUESDAY. AT THIS TIME
IT DOES NOT LOOK LIKE AMOUNTS WILL BE SIGNIFICANT WITH LESS THAN AN
INCH EXPECTED THROUGH TUESDAY. FLURRIES COULD EXTEND FURTHER TO THE
WEST. BY TUESDAY AFTERNOON THE WIND DIRECTION BACKS TO MORE WESTERLY
AND THIS WILL SHUT OFF ANY LAKE ACTIVITY.
ANOTHER WEAK WAVE AND FRONT WILL MOVE THROUGH ON WEDNESDAY...BUT AT
THIS TIME THE MOISTURE AND FORCING WITH THIS FEATURE STAY NORTH OF
THE AREA AND THUS WILL KEEP THE FORECAST DRY.
TEMPERATURES WILL BE COLDER THAN NORMAL EARLY IN THE SHORT TERM AND
START TO REBOUND TO NORMAL ON WEDNESDAY. GENERALLY USED A CONSENSUS
OF GUIDANCE BUT THOUGHT TUESDAY/S MAV HIGHS WERE TOO LOW BASED ON
850 MB TEMPERATURES AND LESS CLOUD COVER SO WENT WITH THE WARMER
GUIDANCE THEN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
OVERALL THE EXTENDED WILL BE RATHER QUIET WITH ABOVE NORMAL
TEMPERATURES AS THE PATTERN TRANSITIONS FROM AN UPPER RIDGE OVER THE
ROCKIES AND A UPPER TROUGH NEAR THE EAST COAST EARLY ON TO A MORE
ZONAL FLOW FROM FRIDAY ON. HIGH PRESSURE MOVING EAST ACROSS THE
SOUTHERN U.S. WILL DOMINATE OUR WEATHER THURSDAY AND FRIDAY. THEN
MODELS BRING A VERY WEAK COLD FRONT ACROSS OUR REGION SATURDAY.
MODELS HAVE TRENDED DRIER WITH THIS COLD FRONT AND NOW INDICATE
PRECIP WILL PASS BOTH NORTH AND SOUTH OF OUR REGION AROUND SATURDAY
BUT MISSING OUR REGION. WILL FOLLOW SUIT AND GO DRY THROUGH THE
PERIOD.
WILL MAKE SOME MINOR ADJUSTMENTS IN TEMPERATURES TO GO A LITTLE
WARMER THAN ALL BLEND AROUND FRIDAY AS WARM ADVECTION WILL BE
OCCURRING AHEAD OF THE COLD FRONT AND SOME OF THE GUIDANCE IS
TRENDING EVEN WARMER. OTHERWISE...ALL BLEND TEMPERATURES LOOK
REASONABLE MOST OTHER PERIODS.
&&
.AVIATION /DISCUSSION FOR THE 02/09Z TAF UPDATE/...
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
A STRONG PRESSURE GRADIENT WILL DECREASE SLIGHTLY OVER CENTRAL
INDIANA AS A SURFACE LOW OVER GREAT LAKES TRACKS TO THE
NORTHEAST...AND FARTHER AWAY FROM THE REGION. WILL CONTINUE OVC
CEILINGS AROUND 4K FT AND -SHSN. RESTRICTIONS TO VIS APPEAR TO BE
AT A MINIMUN SO WILL MAINTAIN VFR. AS FAR AS WINDS ARE CONCERNED
THEY CONTINUE TO DECREASE ONLY SLIGHTLY OVER THE NEXT FEW HOURS
BUT WILL CONTINUE TO GUST EARLY THIS MORNING AND THROUGH
TOMORROW...REACHING AROUND 25 TO 30 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....JEH
AVIATION...SMF/TDUD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1240 AM EST MON JAN 2 2012
...MAJOR WINTER STORM TO IMPACT REGION...
.AVIATION...
RADAR SHOWING POCKETS OF HEAVIER SNOW SHOWERS STILL STRUGGLING TO
CONGEAL WITH 40 TO 50 KNOT 925 TO 850MB LAYER WINDS SHEARING APART
DEVELOPMENT. EXPECT THESE WINDS TO DIMINISH SOMEWHAT OVERNIGHT
ALLOWING BETTER BANDING TO DEVELOP WITH HEAVIER SNOWFALL RATES AND
LOWER VISIBILITIES. PREVIOUS FORECAST ON TRACK WITH NO SIGNIFICANT
CHANGES MADE. LOWER CIGS AND VIS EXPECTED IN STRONGER SNOW SHOWERS
AND UPDATES LIKELY AS THESE DEVELOP AND EVOLVE. FLOW VEERS TO MORE
NORTHWESTERLY DIRECTION MONDAY ALLOWING STRONGER BANDS TO IMPACT
KSBN BEGINNING IN THE MORNING AND REACHING KFWA IN AFTERNOON.
TRAJECTORIES SUGGEST KSBN TO REMAIN NEAR OR IN STRONGEST BAND
THROUGH MONDAY NIGHT. KFWA WILL BE ON SOUTHEAST END OF BAND WITH
MVFR CIGS AND VIS AND OCCASIONAL DROP TO IFR POSSIBLE.
&&
.PREV FORECAST...
WILL EXPAND CAT SNOW MENTION/MEASURABLE QPF FURTHER SWD THIS
EVENING IN REFLECTION OF UPSTREAM ENHANCEMENT DVLPG THROUGH SE WI.
WELL DEFINED SEEDER-FEEDER MECHANISM NOTED EXTENDING DOWNSTREAM IN
COMPOSITE RADAR IMAGERY ACRS NRN IN/SRN MI AND BASED CAT EXPANSION
ON STEADY STATE 290 DEGREE SFC TRAJECTORY. EARLIER HIGHRES MODEL
DATA ALG W/LATEST RUC DATA WOULD SUGGEST ADDNL LL VEERING OVERNIGHT
TWD 310-320 DEGREES AFT 06Z AND PROBABLE GIVEN VAPOR HINTS OF AN
ADDNL SW IMPULSE DROPPING SEWD OUT OF NRN IA THUS EXPANDED CAT SNOW
SHOWER MENTION FURTHER SWD HERE TOO AS WELL.
SFC GRADIENT CONTS TO SLOWLY DIMINISH AND WILL ALLOW BOTH WIND
ADVISORY AND STORM WARNING TO EXPIRE AT 03Z.
AVIATION/UPDATE...
SECONDARY SW TROUGH PIVOTING THROUGH NRN IN ATTM W/ROBUST SHSN
DVLPMNT OVR THE LAST HOUR W/RAPIDLY DETERIORATING FLIGHT CONDS THIS
EVENING. OTHERWISE GROWING LK RESPONSE GOING FORWARD AS CAA WING
DEEPENS BEHIND DEPARTING SW TROUGH AND XPCD MORE COHERENT LK
ENHANCEMENT AFT 03Z TIMED W/ARRIVAL OF MID LVL MSTR POCKET ADVTG
SEWD OUT OF WI W/PRIOR UPDATE DONE TO ACCOUNT FOR THAT. THUS
PRIMARILY MVFR CONDS XPCD THROUGH THE PD W/LIFR CONDS LIKELY MON
AFTN AND MON NIGHT AT KSBN IN HEAVY LK EFFECT SNOW. GUSTY SFC WINDS
WILL CONT THROUGH ABT MIDNIGHT BFR DIMINISHING SOMEWHAT FOR THE
REMAINDER OF THE VALID PD.
SHORT TERM...
TONIGHT THROUGH TUESDAY. CONTD GROWING CONCERN AND CONFIDENCE IN
MAJOR LES EVENT WITH BLSN ADDNL HAZARD. FAVOR LIES TOWARD
NAM12/WRFARW FOR MESOSCALE DETAILING. WRFARW BEST HANDLES GRTLKS
COMPLEX /TRIPLE SHORTWAVE EMBEDDED/ MIDLVL TROUGH UNDERGOING RAPIDLY
DEEPENING IN NEAR TERM AS IT CONTS TO SHARPEN AND SLOWLY TRANSLATE
EWD INTO LWR GRTLKS TONIGHT...AND THEN INTO NEW ENGLAND BY ERLY TUE
TUE...WITH ASSOCD 200-250M/12 HR HGHT FALL CENTROID.
GREATEST NEGATIVE IN NEAR TERM IS CBL FLOW INITIALLY QUITE STRONG
/NEAR 40KTS/ WITH LYR TO LYR SHEAR NOTED TO UNDERMINE MESOSCALE
PROCESSES AND CONSEQUENTIAL LESSER RESIDENCE TIME. INITIAL WEAKER
MULTIBANDS ALREADY UNDERWAY WITH LK/8H DELTA TS INTO MID TEENS
ALREADY. DEEPER/CONCENTRATED CONVECTIVE ROLLS TO LKLY BECOME
ESTABLISHED AS IN CLOUD WINDS DIMINISH TO AROUND 35 KTS BY
DAYBREAK...WITH MORE UNIFORM CBL VECTORING. PER KAZO/KSBN NAM
BUFKIT...DEEP 70-90MB DGZ LYR TOWARD DAYBREAK WITH FAIR DEGREE OF
SATURATION /85-90 PERCENT/ AS DEEPER COLD AIR BECOMES ESTABLISHED
PUSHING DELTA T INTO UPPER TEENS WITH LK/7H DIFFERENTIALS INTO MID
20C RANGE. DEEP THERMAL INSTABILITY TO BE FULLY UTILIZED GIVEN MSTR
DEPTH. GOOD SYNOPTIC MSTR/PRECONDITIONING WITH SFC DPS WELL WINDWARD
OF LK MICHIGAN TO MID 20F FAR NWD TO MN BORDER.
GRAVE CONCERN FOR XTRM SNOWFALL RATES DVLPG MON INTO TUE WITH 5H
THERMAL TROF BOTTOMING OVHD TO M37-38...PERHAPS SUFCNT FOR LTG IN
HVST SQUALLS ESPLY MONDAY AFTN WITH DEEP SATURATION TO 7H WITH LK/7H
DIFFERENTIALS NEARING XTRM VALUES/30C AND LAKE INDUCED CAPE VALUES
APPROACHING 600 J/KG WITH LK INDUCED EQL TO 11.5 KFT. PLANAR VIEW
DEPICTING BEST ORGANIZED CONVERGENCE INITIALLY FM KLWA INTO BRANCH
COUNTY SLIPPING SWD AS WINDS GRDLY VEER FM 305 TO 335 THROUGH THE
DAY. MAXIMUM SNOWFALL RATES GIVEN XTRM INSTABILITY TO 2 INCHES/HR
ANTICIPATED UNDER WHAT SHOULD DVLP INTO PRIMARY SINGLE BAND
EVENT...OR AT LEAST FEWER STRONGER BANDS WITH SRN BAND BECMG UNDER
INFLUENCE OF WRN LK SUPR PRECONDITIONING BY AFTN. DY2 CONVECTION
NOTED AND CERTAINLY PSBL...WL HOLD ON THUNDERSNOW MENTION ATTM GIVEN
AREA/TIMING CONCERNS ATTM FOR LOW PROB EVENT...BUT CERTAINLY OCCRNC
TO PUSH RATES MORE TOWARD 3/HR. FOR NOW HAVE EXPANDED HEADLINES
FURTHER INLAND AND WHILE LES AMOUNTS FURTHER INLAND SIG
LWR...MULTIHAZARDS JUSTIFY UPG/EXPANDED AREA WITH BLSN LEADING TO
FLASH FREEZING/RECOVERING OF ROAD SURFACES/LOW VSBY/WCI DROPPING TO
NEAR ZERO ETC. HAVE RAISED POPS/AMOUNTS IN WARNING AND PERIPHERAL
ADV AREAS...ESP NRN KOS/NRN MARSHALL COUNTIES AND FURTHER INLAND
INTO SCNTL LWR MICHIGAN WITH HIR CONFIDENCE OF AFOREMENTIONED
DOMINANT BAND REACHING/CYLONICALLY CURVING WELL INLAND LTR
TONIGHT/MON AM. CONFIDENCE IN HIR WARNING AMOUNTS NRN BERRIEN/WRN
CASS COUNTIES PER CONTD IMPRESSIVE COBB NAM OUTPUT AT KSBN/KAZO. OF
CONCERN IS SHARP SFC/LLVL RIDGE STAGED STILL WEST OF CWA TUE AM THAT
A FULL AXIS LES BAND TO DVLP AND PERSIST WELL INTO
TUESDAY...PRIMARILY AFFECTING BERRIEN/LAPORTE AS FETCH CONTS TO VEER
ES TO 340 DEGREES AND CBL SLOWS TO LWR 20 KNOTS. WHILE MSTR DEPTH
SIG LESS...CONCERNED THAT MESOSCALE MODELS STILL UNDERPLAYING
COMBINED LK/SUPR/MI AGGREGATE THERMAL TROUGHING FURTHER OUT IN TIME
AND THEREBY NOT CAPTURING FULL POTNL WITH STRONG MSTR
FLUX/CONVERGENCE TO LKLY PERSIST. HAVE RAISED POPS FAR NWRN CWA FOR
FIRST HALF OF TUE AND NOTE POTNL EXTENSION FOR BERRIEN AND LAPORTE
COUNTIES MAY BE NEEDED...BUT CERTAINLY ENOUGH TIME TO ASSESS LTR.
LONG TERM...
TUESDAY NIGHT THROUGH SATURDAY....THE 850 RIDGE AXIS SHOULD HAVE
MOVED JUST EAST OF LAKE MICHIGAN AT THE START OF THIS PERIOD...SO
HAVE KEPT LAKE EFFECT SNOW OUT OF THE FORECAST TUESDAY NIGHT. WARM
AIR ADVECTION WILL BE INCREASING TUESDAY NIGHT AHEAD OF THE NEXT
SYSTEM...SO LOWS TUESDAY NIGHT SHOULD ONLY DROP A FEW DEGREES FROM
THE TUESDAY HIGHS. HOWEVER..A CLIPPER TYPE OF SYSTEM WILL PASS NORTH
OF THE AREA WEDNESDAY. KEPT A CHANCE FOR SNOW BASICALLY OVER THE
NORTHEAST HALF OF THE FORECAST AREA. ISENTROPIC LIFT IS
SUFFICIENT...BUT MOISTURE SOUTH OF THIS SYSTEM IS QUITE LIMITED...SO
EXPECT ANY SNOW AMOUNTS LATE TUESDAY NIGHT AND WEDNESDAY WILL BE
LIGHT. OTHERWISE...AN UPPER LEVEL RIDGE WILL ATTEMPT TO BUILD INTO
THE REGION LATE IN THE WEEK. TEMPERATURES SHOULD WARM MUCH ABOVE
NORMAL BY FRIDAY...WITH HIGHS IN THE LOW TO MID 40S. KEPT A SLIGHT
CHANCE FOR A RAIN OR SNOW SHOWER SATURDAY AS A WEAK TROF MOVES INTO
THE FORECAST AREA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND ADVISORY UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
INZ003>009-012>018-020-022>027-032>034.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR INZ005-006.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR INZ007>009.
WINTER STORM WARNING FROM 4 AM EST /3 AM CST/ MONDAY TO 7 AM
EST
/6 AM CST/ TUESDAY FOR INZ003-004.
WINTER WEATHER ADVISORY FROM 4 AM EST /3 AM CST/ MONDAY TO 7 AM
EST /6 AM CST/ TUESDAY FOR INZ012-014-016.
MI...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR MIZ078>081.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR MIZ077>080.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ081.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ077.
OH...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR OHZ001-002-004-
005-015-016-024-025.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR OHZ001.
LM...STORM WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ043-046.
GALE WARNING FROM 10 PM THIS EVENING TO 11 PM EST MONDAY FOR
LMZ043-046.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...LASHLEY
UPDATE...T
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1128 PM EST SUN JAN 1 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM EXITING THE GREAT LAKES TONIGHT TO THE
NORTHEAST AND STRONG CANADIAN HIGH PRESSURE BUILDING INTO THE PLAINS
WILL KEEP GUSTY WINDS OVER THE AREA THROUGH MONDAY EVENING.
NORTHERLY AND NORTHWESTERLY WINDS OFF LAKE MICHIGAN WILL KEEP LOW
CHANCES FOR LAKE EFFECT SNOW SHOWERS OVER THE NORTHEAST COUNTIES
MONDAY INTO TUESDAY. A BROAD RIDGE OF HIGH PRESSURE WILL THEN
DOMINATE THE WEATHER THROUGH THE REMAINDER OF THE PERIOD AND KEEP
DRY WEATHER IN PLACE. TEMPERATURES WILL DROP BELOW NORMAL FOR THE
BEGINNING OF THE WORK WEEK BUT REBOUND TO NEAR NORMAL BY WEDNESDAY
AND ABOVE NORMAL ON THURSDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
WILL UPDATE SHORTLY TO END THE WIND ADVISORY AND ADD SLIGHT CHANCE
SNOW SHOWERS TO MUCH OF THE AREA.
UPSTREAM WIND GUSTS ARE GENERALLY BELOW CRITERIA AS EXPECTED...AND
OURS HAVE BEEN SLOWLY RELAXING AS WELL. GUSTS TO 35-40 MPH WILL
CONTINUE OVERNIGHT...REMAINING JUST BELOW CRITERIA AT THEIR PEAK.
BROAD AREA OF LIGHT RADAR RETURNS OVER THE REGION...WITH SOME OF
THEM OCCASIONALLY MAKING THE GROUND. WEBCAMS INDICATE A LIGHT
DUSTING IN THE MUNCIE AREA. RUC SOUNDINGS SUGGEST SNOW GROWTH
LAYER SLOWLY MOISTENING OVERNIGHT AS A SECONDARY SHORTWAVE SPINS
AROUND THE BACK SIDE OF THE UPPER TROUGH. THUS...FEEL THAT AT
LEAST A SLIGHT CHANCE OF SNOW SHOWERS IS NECESSARY. NO
ACCUMULATIONS BEYOND A VERY LIGHT DUSTING POSSIBLE...AS DRY AIR
NEAR THE SURFACE WILL BE SUBLIMATING MUCH OF THE SNOW AS IT FALLS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
FORECAST FOCUS IS ON WIND GUSTS MONDAY AND CHANCES FOR SNOW SHOWERS
WITH LAKE EFFECT IN THE WAKE OF THE COLD FRONT. MODELS ARE IN GOOD
AGREEMENT AND WILL USE A CONSENSUS APPROACH.
A TIGHT PRESSURE GRADIENT WILL CONTINUE TO BE IN PLACE MONDAY AS
INDIANA IS BETWEEN STRONG HIGH AND LOW PRESSURE SYSTEMS. THIS WILL
ALLOW SUSTAINED WINDS AROUND 20-25 MPH AND GUSTS OF 30-40 MPH TO
PERSIST THROUGH THE DAY UNTIL THE GRADIENT FINALLY BEGINS TO SLACKEN
MONDAY NIGHT AS THE STRONG LOW FINALLY EXITS UP THE EASTERN CANADIAN
SEABOARD AND HIGH PRESSURE MOVES CLOSER TO INDIANA. AT THIS TIME
FORECAST SOUNDINGS ARE NOT SHOWING WINDS QUITE AS STRONG AS TODAY SO
IT DOES NOT APPEAR THAT ANOTHER ADVISORY WILL BE NECESSARY.
A WEAK IMPULSE WILL MOVE THROUGH THE AREA TOMORROW ON THE BACK SIDE
OF THE LOW...AND THIS EXTRA BIT OF FORCING ALONG WITH 850 MB WINDS
BECOMING NORTH NORTHWESTERLY COULD ALLOW A FEW SNOW SHOWERS TO FORM
ACROSS NORTHEASTERN PARTS OF THE AREA MONDAY AFTERNOON. THESE WINDS
WILL CONTINUE TO PROVIDE A GOOD FETCH ACROSS LAKE MICHIGAN TO
PRODUCE THE POTENTIAL FOR SOME LAKE EFFECT SNOW STRETCHING INTO THE
NORTHEASTERN COUNTIES THROUGH THE MORNING ON TUESDAY. AT THIS TIME
IT DOES NOT LOOK LIKE AMOUNTS WILL BE SIGNIFICANT WITH LESS THAN AN
INCH EXPECTED THROUGH TUESDAY. FLURRIES COULD EXTEND FURTHER TO THE
WEST. BY TUESDAY AFTERNOON THE WIND DIRECTION BACKS TO MORE WESTERLY
AND THIS WILL SHUT OFF ANY LAKE ACTIVITY.
ANOTHER WEAK WAVE AND FRONT WILL MOVE THROUGH ON WEDNESDAY...BUT AT
THIS TIME THE MOISTURE AND FORCING WITH THIS FEATURE STAY NORTH OF
THE AREA AND THUS WILL KEEP THE FORECAST DRY.
TEMPERATURES WILL BE COLDER THAN NORMAL EARLY IN THE SHORT TERM AND
START TO REBOUND TO NORMAL ON WEDNESDAY. GENERALLY USED A CONSENSUS
OF GUIDANCE BUT THOUGHT TUESDAY/S MAV HIGHS WERE TOO LOW BASED ON
850 MB TEMPERATURES AND LESS CLOUD COVER SO WENT WITH THE WARMER
GUIDANCE THEN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
OVERALL THE EXTENDED WILL BE RATHER QUIET WITH ABOVE NORMAL
TEMPERATURES AS THE PATTERN TRANSITIONS FROM AN UPPER RIDGE OVER THE
ROCKIES AND A UPPER TROUGH NEAR THE EAST COAST EARLY ON TO A MORE
ZONAL FLOW FROM FRIDAY ON. HIGH PRESSURE MOVING EAST ACROSS THE
SOUTHERN U.S. WILL DOMINATE OUR WEATHER THURSDAY AND FRIDAY. THEN
MODELS BRING A VERY WEAK COLD FRONT ACROSS OUR REGION SATURDAY.
MODELS HAVE TRENDED DRIER WITH THIS COLD FRONT AND NOW INDICATE
PRECIP WILL PASS BOTH NORTH AND SOUTH OF OUR REGION AROUND SATURDAY
BUT MISSING OUR REGION. WILL FOLLOW SUIT AND GO DRY THROUGH THE
PERIOD.
WILL MAKE SOME MINOR ADJUSTMENTS IN TEMPERATURES TO GO A LITTLE
WARMER THAN ALL BLEND AROUND FRIDAY AS WARM ADVECTION WILL BE
OCCURRING AHEAD OF THE COLD FRONT AND SOME OF THE GUIDANCE IS
TRENDING EVEN WARMER. OTHERWISE...ALL BLEND TEMPERATURES LOOK
REASONABLE MOST OTHER PERIODS.
&&
.AVIATION /DISCUSSION FOR 020600Z IND TAF ISSUANCE/...
A STRONG PRESSURE GRADIENT WILL DECREASE SLIGHTLY OVER CENTRAL
INDIANA AS A SURFACE LOW OVER GREAT LAKES TRACKS TO THE
NORTHEAST...AND FARTHER AWAY FROM THE REGION. WILL CONTINUE OVC
CEILINGS AROUND 4K FT AND -SHSN. RESTRICTIONS TO VIS APPEAR TO BE
AT A MINIMUN SO WILL MAINTAIN VFR. AS FAR AS WINDS ARE CONCERNED
THEY CONTINUE TO DECREASE ONLY SLIGHTLY OVER THE NEXT FEW HOURS
BUT WILL CONTINUE TO GUST EARLY THIS MORNING AND THROUGH
TOMORROW...REACHING AROUND 25 TO 30 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....JEH
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
941 PM EST SUN JAN 1 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM EXITING THE GREAT LAKES TONIGHT TO THE
NORTHEAST AND STRONG CANADIAN HIGH PRESSURE BUILDING INTO THE PLAINS
WILL KEEP GUSTY WINDS OVER THE AREA THROUGH MONDAY EVENING.
NORTHERLY AND NORTHWESTERLY WINDS OFF LAKE MICHIGAN WILL KEEP LOW
CHANCES FOR LAKE EFFECT SNOW SHOWERS OVER THE NORTHEAST COUNTIES
MONDAY INTO TUESDAY. A BROAD RIDGE OF HIGH PRESSURE WILL THEN
DOMINATE THE WEATHER THROUGH THE REMAINDER OF THE PERIOD AND KEEP
DRY WEATHER IN PLACE. TEMPERATURES WILL DROP BELOW NORMAL FOR THE
BEGINNING OF THE WORK WEEK BUT REBOUND TO NEAR NORMAL BY WEDNESDAY
AND ABOVE NORMAL ON THURSDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
WILL UPDATE SHORTLY TO END THE WIND ADVISORY AND ADD SLIGHT CHANCE
SNOW SHOWERS TO MUCH OF THE AREA.
UPSTREAM WIND GUSTS ARE GENERALLY BELOW CRITERIA AS EXPECTED...AND
OURS HAVE BEEN SLOWLY RELAXING AS WELL. GUSTS TO 35-40 MPH WILL
CONTINUE OVERNIGHT...REMAINING JUST BELOW CRITERIA AT THEIR PEAK.
BROAD AREA OF LIGHT RADAR RETURNS OVER THE REGION...WITH SOME OF
THEM OCCASIONALLY MAKING THE GROUND. WEBCAMS INDICATE A LIGHT
DUSTING IN THE MUNCIE AREA. RUC SOUNDINGS SUGGEST SNOW GROWTH
LAYER SLOWLY MOISTENING OVERNIGHT AS A SECONDARY SHORTWAVE SPINS
AROUND THE BACK SIDE OF THE UPPER TROUGH. THUS...FEEL THAT AT
LEAST A SLIGHT CHANCE OF SNOW SHOWERS IS NECESSARY. NO
ACCUMULATIONS BEYOND A VERY LIGHT DUSTING POSSIBLE...AS DRY AIR
NEAR THE SURFACE WILL BE SUBLIMATING MUCH OF THE SNOW AS IT FALLS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
FORECAST FOCUS IS ON WIND GUSTS MONDAY AND CHANCES FOR SNOW SHOWERS
WITH LAKE EFFECT IN THE WAKE OF THE COLD FRONT. MODELS ARE IN GOOD
AGREEMENT AND WILL USE A CONSENSUS APPROACH.
A TIGHT PRESSURE GRADIENT WILL CONTINUE TO BE IN PLACE MONDAY AS
INDIANA IS BETWEEN STRONG HIGH AND LOW PRESSURE SYSTEMS. THIS WILL
ALLOW SUSTAINED WINDS AROUND 20-25 MPH AND GUSTS OF 30-40 MPH TO
PERSIST THROUGH THE DAY UNTIL THE GRADIENT FINALLY BEGINS TO SLACKEN
MONDAY NIGHT AS THE STRONG LOW FINALLY EXITS UP THE EASTERN CANADIAN
SEABOARD AND HIGH PRESSURE MOVES CLOSER TO INDIANA. AT THIS TIME
FORECAST SOUNDINGS ARE NOT SHOWING WINDS QUITE AS STRONG AS TODAY SO
IT DOES NOT APPEAR THAT ANOTHER ADVISORY WILL BE NECESSARY.
A WEAK IMPULSE WILL MOVE THROUGH THE AREA TOMORROW ON THE BACK SIDE
OF THE LOW...AND THIS EXTRA BIT OF FORCING ALONG WITH 850 MB WINDS
BECOMING NORTH NORTHWESTERLY COULD ALLOW A FEW SNOW SHOWERS TO FORM
ACROSS NORTHEASTERN PARTS OF THE AREA MONDAY AFTERNOON. THESE WINDS
WILL CONTINUE TO PROVIDE A GOOD FETCH ACROSS LAKE MICHIGAN TO
PRODUCE THE POTENTIAL FOR SOME LAKE EFFECT SNOW STRETCHING INTO THE
NORTHEASTERN COUNTIES THROUGH THE MORNING ON TUESDAY. AT THIS TIME
IT DOES NOT LOOK LIKE AMOUNTS WILL BE SIGNIFICANT WITH LESS THAN AN
INCH EXPECTED THROUGH TUESDAY. FLURRIES COULD EXTEND FURTHER TO THE
WEST. BY TUESDAY AFTERNOON THE WIND DIRECTION BACKS TO MORE WESTERLY
AND THIS WILL SHUT OFF ANY LAKE ACTIVITY.
ANOTHER WEAK WAVE AND FRONT WILL MOVE THROUGH ON WEDNESDAY...BUT AT
THIS TIME THE MOISTURE AND FORCING WITH THIS FEATURE STAY NORTH OF
THE AREA AND THUS WILL KEEP THE FORECAST DRY.
TEMPERATURES WILL BE COLDER THAN NORMAL EARLY IN THE SHORT TERM AND
START TO REBOUND TO NORMAL ON WEDNESDAY. GENERALLY USED A CONSENSUS
OF GUIDANCE BUT THOUGHT TUESDAY/S MAV HIGHS WERE TOO LOW BASED ON
850 MB TEMPERATURES AND LESS CLOUD COVER SO WENT WITH THE WARMER
GUIDANCE THEN.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
OVERALL THE EXTENDED WILL BE RATHER QUIET WITH ABOVE NORMAL
TEMPERATURES AS THE PATTERN TRANSITIONS FROM AN UPPER RIDGE OVER THE
ROCKIES AND A UPPER TROUGH NEAR THE EAST COAST EARLY ON TO A MORE
ZONAL FLOW FROM FRIDAY ON. HIGH PRESSURE MOVING EAST ACROSS THE
SOUTHERN U.S. WILL DOMINATE OUR WEATHER THURSDAY AND FRIDAY. THEN
MODELS BRING A VERY WEAK COLD FRONT ACROSS OUR REGION SATURDAY.
MODELS HAVE TRENDED DRIER WITH THIS COLD FRONT AND NOW INDICATE
PRECIP WILL PASS BOTH NORTH AND SOUTH OF OUR REGION AROUND SATURDAY
BUT MISSING OUR REGION. WILL FOLLOW SUIT AND GO DRY THROUGH THE
PERIOD.
WILL MAKE SOME MINOR ADJUSTMENTS IN TEMPERATURES TO GO A LITTLE
WARMER THAN ALL BLEND AROUND FRIDAY AS WARM ADVECTION WILL BE
OCCURRING AHEAD OF THE COLD FRONT AND SOME OF THE GUIDANCE IS
TRENDING EVEN WARMER. OTHERWISE...ALL BLEND TEMPERATURES LOOK
REASONABLE MOST OTHER PERIODS.
&&
.AVIATION /DISCUSSION FOR 020000 IND TAF ISSUANCE/...
0230Z UPDATE...ADDED A TEMPO GROUP FOR 2 HR OF MFVR VIS DUE TO
-SN...BASED ON OBS UPSTREAM. OTHERWISE FORECAST LOOKS
REPRESENTATIVE. PREVIOUS DISC FOLLOWS.
00Z UPDATE...A FEW FLAKES ARE REACHING THE SURFACE IN THE
INDIANAPOLIS AREA AND OTHER LOCATIONS SO WILL HAVE -SHSN TO TAFS
BUT WITH NOT RESTRICTIONS. PREVIOUS DISC FOLLOWS.
A STRONG PRESSURE GRADIENT WILL DECREASE SLIGHTLY OVER CENTRAL
INDIANA IN THE NEXT 24 HOURS AS SURFACE LOW OVER GREAT LAKES
TRACKS TO THE NORTHEAST...AND FARTHER AWAY FROM THE REGION.
THE AREA SAW A BRIEF CLEARING EARLIER THIS AFTERNOON...HOWEVER
BKN-OVC LOW CEILINGS AROUND 35 HND FT AREA BEGINNING TO INFILTRATE
ACROSS THE AREA. HAVE THEREFORE STARTED THIS TAF PERIOD WITH BKN-
OVC CEILINGS. THINKING THAT ANY SNOW SHOWER ACTIVITY SHOULD STAYED
CONFINED TO THE NE COUNTIES AND AWAY FROM ANY OF THE FORECAST
TERMINALS SO WILL REFRAIN FROM MENTIONING -SHSN ATTM.
AS FAR AS WINDS ARE CONCERNED THEY CONTINUE TO DECREASE ONLY
SLIGHTLY OVER THE NEXT FEW HOURS BUT WILL GUSTS OVERNIGHT AND INTO
TOMORROW...REACHING AROUND 25 TO 30 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....JEH
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
924 PM EST SUN JAN 1 2012
...MAJOR WINTER STORM TO IMPACT REGION...
.UPDATE...
WILL EXPAND CAT SNOW MENTION/MEASURABLE QPF FURTHER SWD THIS
EVENING IN REFLECTION OF UPSTREAM ENHANCEMENT DVLPG THROUGH SE WI.
WELL DEFINED SEEDER-FEEDER MECHANISM NOTED EXTENDING DOWNSTREAM IN
COMPOSITE RADAR IMAGERY ACRS NRN IN/SRN MI AND BASED CAT EXPANSION
ON STEADY STATE 290 DEGREE SFC TRAJECTORY. EARLIER HIGHRES MODEL
DATA ALG W/LATEST RUC DATA WOULD SUGGEST ADDNL LL VEERING OVERNIGHT
TWD 310-320 DEGREES AFT 06Z AND PROBABLE GIVEN VAPOR HINTS OF AN
ADDNL SW IMPULSE DROPPING SEWD OUT OF NRN IA THUS EXPANDED CAT SNOW
SHOWER MENTION FURTHER SWD HERE TOO AS WELL.
SFC GRADIENT CONTS TO SLOWLY DIMINISH AND WILL ALLOW BOTH WIND
ADVISORY AND STORM WARNING TO EXPIRE AT 03Z.
&&
.AVIATION/UPDATE...
SECONDARY SW TROUGH PIVOTING THROUGH NRN IN ATTM W/ROBUST SHSN
DVLPMNT OVR THE LAST HOUR W/RAPIDLY DETERIORATING FLIGHT CONDS THIS
EVENING. OTHERWISE GROWING LK RESPONSE GOING FORWARD AS CAA WING
DEEPENS BEHIND DEPARTING SW TROUGH AND XPCD MORE COHERENT LK
ENHANCEMENT AFT 03Z TIMED W/ARRIVAL OF MID LVL MSTR POCKET ADVTG
SEWD OUT OF WI W/PRIOR UPDATE DONE TO ACCOUNT FOR THAT. THUS
PRIMARILY MVFR CONDS XPCD THROUGH THE PD W/LIFR CONDS LIKELY MON
AFTN AND MON NIGHT AT KSBN IN HEAVY LK EFFECT SNOW. GUSTY SFC WINDS
WILL CONT THROUGH ABT MIDNIGHT BFR DIMINISHING SOMEWHAT FOR THE
REMAINDER OF THE VALID PD.
&&
.SHORT TERM...
TONIGHT THROUGH TUESDAY. CONTD GROWING CONCERN AND CONFIDENCE IN
MAJOR LES EVENT WITH BLSN ADDNL HAZARD. FAVOR LIES TOWARD
NAM12/WRFARW FOR MESOSCALE DETAILING. WRFARW BEST HANDLES GRTLKS
COMPLEX /TRIPLE SHORTWAVE EMBEDDED/ MIDLVL TROUGH UNDERGOING RAPIDLY
DEEPENING IN NEAR TERM AS IT CONTS TO SHARPEN AND SLOWLY TRANSLATE
EWD INTO LWR GRTLKS TONIGHT...AND THEN INTO NEW ENGLAND BY ERLY TUE
TUE...WITH ASSOCD 200-250M/12 HR HGHT FALL CENTROID.
GREATEST NEGATIVE IN NEAR TERM IS CBL FLOW INITIALLY QUITE STRONG
/NEAR 40KTS/ WITH LYR TO LYR SHEAR NOTED TO UNDERMINE MESOSCALE
PROCESSES AND CONSEQUENTIAL LESSER RESIDENCE TIME. INITIAL WEAKER
MULTIBANDS ALREADY UNDERWAY WITH LK/8H DELTA TS INTO MID TEENS
ALREADY. DEEPER/CONCENTRATED CONVECTIVE ROLLS TO LKLY BECOME
ESTABLISHED AS IN CLOUD WINDS DIMINISH TO AROUND 35 KTS BY
DAYBREAK...WITH MORE UNIFORM CBL VECTORING. PER KAZO/KSBN NAM
BUFKIT...DEEP 70-90MB DGZ LYR TOWARD DAYBREAK WITH FAIR DEGREE OF
SATURATION /85-90 PERCENT/ AS DEEPER COLD AIR BECOMES ESTABLISHED
PUSHING DELTA T INTO UPPER TEENS WITH LK/7H DIFFERENTIALS INTO MID
20C RANGE. DEEP THERMAL INSTABILITY TO BE FULLY UTILIZED GIVEN MSTR
DEPTH. GOOD SYNOPTIC MSTR/PRECONDITIONING WITH SFC DPS WELL WINDWARD
OF LK MICHIGAN TO MID 20F FAR NWD TO MN BORDER.
GRAVE CONCERN FOR XTRM SNOWFALL RATES DVLPG MON INTO TUE WITH 5H
THERMAL TROF BOTTOMING OVHD TO M37-38...PERHAPS SUFCNT FOR LTG IN
HVST SQUALLS ESPLY MONDAY AFTN WITH DEEP SATURATION TO 7H WITH LK/7H
DIFFERENTIALS NEARING XTRM VALUES/30C AND LAKE INDUCED CAPE VALUES
APPROACHING 600 J/KG WITH LK INDUCED EQL TO 11.5 KFT. PLANAR VIEW
DEPICTING BEST ORGANIZED CONVERGENCE INITIALLY FM KLWA INTO BRANCH
COUNTY SLIPPING SWD AS WINDS GRDLY VEER FM 305 TO 335 THROUGH THE
DAY. MAXIMUM SNOWFALL RATES GIVEN XTRM INSTABILITY TO 2 INCHES/HR
ANTICIPATED UNDER WHAT SHOULD DVLP INTO PRIMARY SINGLE BAND
EVENT...OR AT LEAST FEWER STRONGER BANDS WITH SRN BAND BECMG UNDER
INFLUENCE OF WRN LK SUPR PRECONDITIONING BY AFTN. DY2 CONVECTION
NOTED AND CERTAINLY PSBL...WL HOLD ON THUNDERSNOW MENTION ATTM GIVEN
AREA/TIMING CONCERNS ATTM FOR LOW PROB EVENT...BUT CERTAINLY OCCRNC
TO PUSH RATES MORE TOWARD 3/HR. FOR NOW HAVE EXPANDED HEADLINES
FURTHER INLAND AND WHILE LES AMOUNTS FURTHER INLAND SIG
LWR...MULTIHAZARDS JUSTIFY UPG/EXPANDED AREA WITH BLSN LEADING TO
FLASH FREEZING/RECOVERING OF ROAD SURFACES/LOW VSBY/WCI DROPPING TO
NEAR ZERO ETC. HAVE RAISED POPS/AMOUNTS IN WARNING AND PERIPHERAL
ADV AREAS...ESP NRN KOS/NRN MARSHALL COUNTIES AND FURTHER INLAND
INTO SCNTL LWR MICHIGAN WITH HIR CONFIDENCE OF AFOREMENTIONED
DOMINANT BAND REACHING/CYLONICALLY CURVING WELL INLAND LTR
TONIGHT/MON AM. CONFIDENCE IN HIR WARNING AMOUNTS NRN BERRIEN/WRN
CASS COUNTIES PER CONTD IMPRESSIVE COBB NAM OUTPUT AT KSBN/KAZO. OF
CONCERN IS SHARP SFC/LLVL RIDGE STAGED STILL WEST OF CWA TUE AM THAT
A FULL AXIS LES BAND TO DVLP AND PERSIST WELL INTO
TUESDAY...PRIMARILY AFFECTING BERRIEN/LAPORTE AS FETCH CONTS TO VEER
ES TO 340 DEGREES AND CBL SLOWS TO LWR 20 KNOTS. WHILE MSTR DEPTH
SIG LESS...CONCERNED THAT MESOSCALE MODELS STILL UNDERPLAYING
COMBINED LK/SUPR/MI AGGREGATE THERMAL TROUGHING FURTHER OUT IN TIME
AND THEREBY NOT CAPTURING FULL POTNL WITH STRONG MSTR
FLUX/CONVERGENCE TO LKLY PERSIST. HAVE RAISED POPS FAR NWRN CWA FOR
FIRST HALF OF TUE AND NOTE POTNL EXTENSION FOR BERRIEN AND LAPORTE
COUNTIES MAY BE NEEDED...BUT CERTAINLY ENOUGH TIME TO ASSESS LTR.
&&
.LONG TERM...
TUESDAY NIGHT THROUGH SATURDAY....THE 850 RIDGE AXIS SHOULD HAVE
MOVED JUST EAST OF LAKE MICHIGAN AT THE START OF THIS PERIOD...SO
HAVE KEPT LAKE EFFECT SNOW OUT OF THE FORECAST TUESDAY NIGHT. WARM
AIR ADVECTION WILL BE INCREASING TUESDAY NIGHT AHEAD OF THE NEXT
SYSTEM...SO LOWS TUESDAY NIGHT SHOULD ONLY DROP A FEW DEGREES FROM
THE TUESDAY HIGHS. HOWEVER..A CLIPPER TYPE OF SYSTEM WILL PASS NORTH
OF THE AREA WEDNESDAY. KEPT A CHANCE FOR SNOW BASICALLY OVER THE
NORTHEAST HALF OF THE FORECAST AREA. ISENTROPIC LIFT IS
SUFFICIENT...BUT MOISTURE SOUTH OF THIS SYSTEM IS QUITE LIMITED...SO
EXPECT ANY SNOW AMOUNTS LATE TUESDAY NIGHT AND WEDNESDAY WILL BE
LIGHT. OTHERWISE...AN UPPER LEVEL RIDGE WILL ATTEMPT TO BUILD INTO
THE REGION LATE IN THE WEEK. TEMPERATURES SHOULD WARM MUCH ABOVE
NORMAL BY FRIDAY...WITH HIGHS IN THE LOW TO MID 40S. KEPT A SLIGHT
CHANCE FOR A RAIN OR SNOW SHOWER SATURDAY AS A WEAK TROF MOVES INTO
THE FORECAST AREA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND ADVISORY UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
INZ003>009-012>018-020-022>027-032>034.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR INZ005-006.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR INZ007>009.
WINTER STORM WARNING FROM 4 AM EST /3 AM CST/ MONDAY TO 7 AM EST
/6 AM CST/ TUESDAY FOR INZ003-004.
WINTER WEATHER ADVISORY FROM 4 AM EST /3 AM CST/ MONDAY TO 7 AM
EST /6 AM CST/ TUESDAY FOR INZ012-014-016.
MI...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR MIZ078>081.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR MIZ077>080.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ081.
HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ077.
OH...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR OHZ001-002-004-
005-015-016-024-025.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR OHZ001.
LM...STORM WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ043-046.
GALE WARNING FROM 10 PM THIS EVENING TO 11 PM EST MONDAY FOR
LMZ043-046.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...T
UPDATE...T
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
744 AM CST SAT DEC 31 2011
.UPDATE...
MINOR UPDATE TO BETTER REFLECT CURRENT CLOUD TRENDS. LOCALLY DENSE
FOG IS SLOWLY IMPROVING AS THE INVERTED TROF CONTINUES MOVING EAST.
..08..
&&
.PREV DISCUSSION... /ISSUED 548 AM CST SAT DEC 31 2011/
AVIATION...
VLIFR TO MVFR CONDITIONS WILL IMPROVE TO VFR THROUGH 18Z/31. LLWS
APPEARS TO BE MARGINAL AHEAD OF A STORM SYSTEM 21Z/31 TO 02Z/01
BUT LOW LEVEL TURBULENCE IS LIKELY. AFT 03Z/01 CONDITIONS WILL
DETERIORATE WITH RA DVLPG. CIGS WERE KEPT VFR BUT MVFR CONDITIONS
ARE POSSIBLE AFT 03Z/01. STRONG COLD FRONT CHANGES RA TO SN AFT
06Z/01 WITH WINDS INCREASING SIGNIFICANTLY. THERE ARE QUESTIONS
AS TO WHETHER THE 40-50 KT WINDS ARND 2KFT AGL WILL MIX DOWN TO
THE SURFACE. IF NO MIXING DOWN OCCURS THEN THERE IS A POTENTIAL
FOR LLWS AFT 06Z/01.
.08..
PREV DISCUSSION... /ISSUED 335 AM CST SAT DEC 31 2011/
SYNOPSIS...
06Z SFC ANALYSIS HAS A LOW IN NORTHWEST SOUTH DAKOTA WITH A WARM
FRONT RUNNING SOUTHEAST TO NEAR KSUX. A TROF RAN FROM A LOW IN
SOUTHERN LAKE HURON INTO CENTRAL ILLINOIS AND THEN NORTHWEST INTO
SOUTHEAST MINNESOTA. DEW POINTS WERE GENERALLY IN THE 20S AND 30S
ACROSS THE MIDWEST. SATELLITE HAS AN AREA OF LOW CLOUDS ACROSS
EASTERN IOWA AND MOST OF ILLINOIS TRAPPED UNDER AN INVERSION WITH
MID AND HIGH CLOUDS MOVING EAST FROM THE ROCKIES.
SHORT TERM...TODAY AND TONIGHT
THERE ARE MANY CONCERNS OVER THE NEXT 36 HRS. IN THE IMMEDIATE
SHORT TERM ARE THE CLOUDS AND FOG POTENTIAL. THE LOW CLOUDS ACROSS
THE AREA ARE TRAPPED UNDER AN INVERSION. RUC TRENDS MAINTAIN THE
INVERSION FOR MOST OF THE MORNING BEFORE BREAKING IT UP AROUND MID
DAY. IF CORRECT...THEN THE CLOUD COVER WILL HOLD DOWN TEMPERATURES
TODAY. AS FOR THE FOG...IT IS ONLY PATCHY IN SPOTS RIGHT NOW AND
IT WILL BE MONITORED. AN SPS MAY BE ISSUED FOR THOSE AREAS WHERE
THE FOG IS LOCALLY DENSE.
THE CLOUDS SHOULD BREAK UP DURING THE DAY RESULTING IN A QUIET AND
MILD DAY FOR THE LAST DAY OF DECEMBER. ATTENTION THEN TURNS TO THE
APPROACHING SYSTEM FOR TONIGHT.
FIRST...ALL MODELS INITIALIZED TOO MOIST IN THE LOWER LEVELS WHEN
COMPARED AGAINST THE 00Z UA DATA. THIS MOIST BIAS IS LIKELY
RESULTING IN THE MODELS PUTTING OUT TOO MUCH QPF FOR TONIGHT.
BASED ON THE OVERALL FORCING AND CONDENSATION PRESSURE DEFICITS
THE EARLY EVENING HOURS WILL BE DRY WITH THE PRECIPITATION
REMAINING IN CENTRAL IOWA. BETWEEN 9 PM AND MIDNIGHT...RAIN WILL
DEVELOP OR MOVE INTO THE WESTERN CWFA AS CONTINUED WAA OCCURS AND
TEMPERATURES ALOFT REMAIN ABOVE 0 CELSIUS.
AFTER MIDNIGHT...STRONG CAA OCCURS AS THE FRONT MOVES THROUGH.
FCST SOUNDINGS QUICKLY DROP BELOW FREEZING AND WBZ TEMPERATURES
DROP BELOW FREEZING AS WELL. THUS MIDNIGHT TO 3 AM WILL SEE A
FAIRLY RAPID TRANSITION FROM RAIN TO SNOW WITH A MIX FOR A FEW
HOURS. AFTER 3 AM...CAA CONTINUES AND SNOW SHOULD BE SEEN ACROSS
THE ENTIRE AREA. THIS EVENT WILL ONLY LAST ABOUT 6-7 HRS IN ANY
ONE LOCATION ONCE IT BEGINS.
SINCE ABOUT HALF OF THE EVENT WILL BE RAIN...THE SNOW AMOUNTS WILL
BE QUITE LIGHT AND SHOULD BE AT WORST ONE HALF INCH. MOST AREAS
WILL ONLY SEE A DUSTING OF ACCUMULATION.
THE OTHER CONCERN IS THE WIND. THE STRONG CAA COMBINED WITH A
STRONG PRESSURE GRADIENT WILL RESULT IN VERY STRONG WINDS. WINDS
ARE PROGGED TO BE NEAR 50 KNOTS STARTING JUST ABOVE 925 MB.
HOWEVER...LOW LEVEL LAPSE RATES ARE NOT OVERLY STEEP SO THE HIGHER
MOMENTUM AIR ALOFT MAY HAVE TROUBLE MIXING DOWN TO THE SFC.
SINCE A WIND ADVISORY IS ALREADY OUT...IT WILL BE CONTINUED.
HOWEVER...THE START TIME WILL BE PUSHED BACK TO MIDNIGHT AND THE
AREAL COVERAGE WILL BE EXPANDED AS WELL.
08..
LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY WILL BE VERY WINDY...SUNDAY NIGHT THROUGH MONDAY EVENING WILL
BE RATHER WINDY TOO. MOST OTHER QUESTIONS ARE CONCERNED WITH CLOUD
COVER AND THE AFFECT ON TEMPERATURES THROUGH THE EARLY WEEK.
OTHERWISE THE EXTENDED FORECAST GENERALLY REMAINS UNCHANGED AS WE
SEE ANOTHER SEVERAL DAYS OF VERY MILD WEATHER IN THE WEDNESDAY
THROUGH FRIDAY PERIOD.
SUNDAY...WE WILL BEGIN THE DAY WITH STRONG CAA AND STRATUS LIKELY
SPREADING OVER THE AREA. ANY MOISTURE SEEMS VERY THIN...THUS
FLURRIES ARE NOT INCLUDED YET. EARLY DAY WILL BE WINDY...WITH SOME
WIND GUSTS BEFORE 9 AM REACHING UP AROUND 40 MPH IN THE
NORTHWEST...AND 35 MPH ELSEWHERE. BETWEEN 9 AM AND SUNSET...WE
SHOULD SEE WIND ADVISORY LEVELS IN MOST OF THE CWA. AT THIS
POINT...OUR COUNTIES ALONG AND WEST OF THE MISSISSIPPI RIVER LOOK
VERY LIKELY TO SEE WIND GUSTS OVER 45 MPH AT TIMES MID DAY SUNDAY.
SOME GUSTS TO AROUND 50 MPH ARE POSSIBLE SUNDAY NOON THROUGH 2 PM
SUNDAY. WITH THE CERTAINTY OF WIND CRITERIA OVER THE WESTERN HALF OF
THE CWA...WILL EXTEND THE ADVISORY FURTHER EAST. THOUGH THE
COUNTIES JUST EAST WILL POSSIBLY HIT CRITERIA AS WELL...THEY APPEAR
MORE MARGINAL AT THIS TIME...AND WITH ONSET CLOSER TO 12Z SUNDAY IN
THOSE LOCATIONS...WILL KEEP THEM OUT OF THE ADVISORY.
SUNDAY NIGHT...WINDS MAY REMAIN NEAR ADVISORY LEVELS THROUGH THE
EVENING...AND CURRENT HEADLINES KEEP OUR NORTHWEST COUNTIES IN ONE
THROUGH 06Z MONDAY. TEMPERATURES WILL DROP INTO THE TEENS SUNDAY
EVENING...AND MAY FALL TO THE RANGE OF 10 TO 15 BY MONDAY MORNING.
WIND CHILLS IN THE TEENS SUNDAY WILL DROP TO THE -8 TO +5 RANGE BY
MONDAY MORNING. 2012 WILL CERTAINLY ENTER WITH A GOOD DOSE OF WINTER
TEMPERATURES...THIS COLD SNAP WILL BE OVER QUITE QUICKLY.
AFTER A COLD NIGHT MONDAY NIGHT...TUESDAY WILL BEGIN OUR NEXT WARM
UP...AS ZONAL FLOW DEVELOPS ALOFT. BY THURSDAY AND
FRIDAY...TEMPERATURES COULD EASILY REACH THE 50S IN MANY PARTS OF
THE CWA.
ERVIN..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR
BENTON-CEDAR-CLINTON-DES MOINES-HENRY IA-IOWA-JACKSON-
JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-MUSCATINE-
SCOTT-VAN BUREN-WASHINGTON.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT
FOR BUCHANAN-DELAWARE-DUBUQUE.
IL...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR JO
DAVIESS-MERCER-ROCK ISLAND.
MO...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR CLARK-
SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
548 AM CST SAT DEC 31 2011
.AVIATION...
VLIFR TO MVFR CONDITIONS WILL IMPROVE TO VFR THROUGH 18Z/31. LLWS
APPEARS TO BE MARGINAL AHEAD OF A STORM SYSTEM 21Z/31 TO 02Z/01
BUT LOW LEVEL TURBULENCE IS LIKELY. AFT 03Z/01 CONDITIONS WILL
DETERIORATE WITH RA DVLPG. CIGS WERE KEPT VFR BUT MVFR CONDITIONS
ARE POSSIBLE AFT 03Z/01. STRONG COLD FRONT CHANGES RA TO SN AFT
06Z/01 WITH WINDS INCREASING SIGNIFICANTLY. THERE ARE QUESTIONS
AS TO WHETHER THE 40-50 KT WINDS ARND 2KFT AGL WILL MIX DOWN TO
THE SURFACE. IF NO MIXING DOWN OCCURS THEN THERE IS A POTENTIAL
FOR LLWS AFT 06Z/01.
..08..
&&
.PREV DISCUSSION... /ISSUED 335 AM CST SAT DEC 31 2011/
SYNOPSIS...
06Z SFC ANALYSIS HAS A LOW IN NORTHWEST SOUTH DAKOTA WITH A WARM
FRONT RUNNING SOUTHEAST TO NEAR KSUX. A TROF RAN FROM A LOW IN
SOUTHERN LAKE HURON INTO CENTRAL ILLINOIS AND THEN NORTHWEST INTO
SOUTHEAST MINNESOTA. DEW POINTS WERE GENERALLY IN THE 20S AND 30S
ACROSS THE MIDWEST. SATELLITE HAS AN AREA OF LOW CLOUDS ACROSS
EASTERN IOWA AND MOST OF ILLINOIS TRAPPED UNDER AN INVERSION WITH
MID AND HIGH CLOUDS MOVING EAST FROM THE ROCKIES.
SHORT TERM...TODAY AND TONIGHT
THERE ARE MANY CONCERNS OVER THE NEXT 36 HRS. IN THE IMMEDIATE
SHORT TERM ARE THE CLOUDS AND FOG POTENTIAL. THE LOW CLOUDS ACROSS
THE AREA ARE TRAPPED UNDER AN INVERSION. RUC TRENDS MAINTAIN THE
INVERSION FOR MOST OF THE MORNING BEFORE BREAKING IT UP AROUND MID
DAY. IF CORRECT...THEN THE CLOUD COVER WILL HOLD DOWN TEMPERATURES
TODAY. AS FOR THE FOG...IT IS ONLY PATCHY IN SPOTS RIGHT NOW AND
IT WILL BE MONITORED. AN SPS MAY BE ISSUED FOR THOSE AREAS WHERE
THE FOG IS LOCALLY DENSE.
THE CLOUDS SHOULD BREAK UP DURING THE DAY RESULTING IN A QUIET AND
MILD DAY FOR THE LAST DAY OF DECEMBER. ATTENTION THEN TURNS TO THE
APPROACHING SYSTEM FOR TONIGHT.
FIRST...ALL MODELS INITIALIZED TOO MOIST IN THE LOWER LEVELS WHEN
COMPARED AGAINST THE 00Z UA DATA. THIS MOIST BIAS IS LIKELY
RESULTING IN THE MODELS PUTTING OUT TOO MUCH QPF FOR TONIGHT.
BASED ON THE OVERALL FORCING AND CONDENSATION PRESSURE DEFICITS
THE EARLY EVENING HOURS WILL BE DRY WITH THE PRECIPITATION
REMAINING IN CENTRAL IOWA. BETWEEN 9 PM AND MIDNIGHT...RAIN WILL
DEVELOP OR MOVE INTO THE WESTERN CWFA AS CONTINUED WAA OCCURS AND
TEMPERATURES ALOFT REMAIN ABOVE 0 CELSIUS.
AFTER MIDNIGHT...STRONG CAA OCCURS AS THE FRONT MOVES THROUGH.
FCST SOUNDINGS QUICKLY DROP BELOW FREEZING AND WBZ TEMPERATURES
DROP BELOW FREEZING AS WELL. THUS MIDNIGHT TO 3 AM WILL SEE A
FAIRLY RAPID TRANSITION FROM RAIN TO SNOW WITH A MIX FOR A FEW
HOURS. AFTER 3 AM...CAA CONTINUES AND SNOW SHOULD BE SEEN ACROSS
THE ENTIRE AREA. THIS EVENT WILL ONLY LAST ABOUT 6-7 HRS IN ANY
ONE LOCATION ONCE IT BEGINS.
SINCE ABOUT HALF OF THE EVENT WILL BE RAIN...THE SNOW AMOUNTS WILL
BE QUITE LIGHT AND SHOULD BE AT WORST ONE HALF INCH. MOST AREAS
WILL ONLY SEE A DUSTING OF ACCUMULATION.
THE OTHER CONCERN IS THE WIND. THE STRONG CAA COMBINED WITH A
STRONG PRESSURE GRADIENT WILL RESULT IN VERY STRONG WINDS. WINDS
ARE PROGGED TO BE NEAR 50 KNOTS STARTING JUST ABOVE 925 MB.
HOWEVER...LOW LEVEL LAPSE RATES ARE NOT OVERLY STEEP SO THE HIGHER
MOMENTUM AIR ALOFT MAY HAVE TROUBLE MIXING DOWN TO THE SFC.
SINCE A WIND ADVISORY IS ALREADY OUT...IT WILL BE CONTINUED.
HOWEVER...THE START TIME WILL BE PUSHED BACK TO MIDNIGHT AND THE
AREAL COVERAGE WILL BE EXPANDED AS WELL.
.08..
LONG TERM...SUNDAY THROUGH FRIDAY...
SUNDAY WILL BE VERY WINDY...SUNDAY NIGHT THROUGH MONDAY EVENING WILL
BE RATHER WINDY TOO. MOST OTHER QUESTIONS ARE CONCERNED WITH CLOUD
COVER AND THE AFFECT ON TEMPERATURES THROUGH THE EARLY WEEK.
OTHERWISE THE EXTENDED FORECAST GENERALLY REMAINS UNCHANGED AS WE
SEE ANOTHER SEVERAL DAYS OF VERY MILD WEATHER IN THE WEDNESDAY
THROUGH FRIDAY PERIOD.
SUNDAY...WE WILL BEGIN THE DAY WITH STRONG CAA AND STRATUS LIKELY
SPREADING OVER THE AREA. ANY MOISTURE SEEMS VERY THIN...THUS
FLURRIES ARE NOT INCLUDED YET. EARLY DAY WILL BE WINDY...WITH SOME
WIND GUSTS BEFORE 9 AM REACHING UP AROUND 40 MPH IN THE
NORTHWEST...AND 35 MPH ELSEWHERE. BETWEEN 9 AM AND SUNSET...WE
SHOULD SEE WIND ADVISORY LEVELS IN MOST OF THE CWA. AT THIS
POINT...OUR COUNTIES ALONG AND WEST OF THE MISSISSIPPI RIVER LOOK
VERY LIKELY TO SEE WIND GUSTS OVER 45 MPH AT TIMES MID DAY SUNDAY.
SOME GUSTS TO AROUND 50 MPH ARE POSSIBLE SUNDAY NOON THROUGH 2 PM
SUNDAY. WITH THE CERTAINTY OF WIND CRITERIA OVER THE WESTERN HALF OF
THE CWA...WILL EXTEND THE ADVISORY FURTHER EAST. THOUGH THE
COUNTIES JUST EAST WILL POSSIBLY HIT CRITERIA AS WELL...THEY APPEAR
MORE MARGINAL AT THIS TIME...AND WITH ONSET CLOSER TO 12Z SUNDAY IN
THOSE LOCATIONS...WILL KEEP THEM OUT OF THE ADVISORY.
SUNDAY NIGHT...WINDS MAY REMAIN NEAR ADVISORY LEVELS THROUGH THE
EVENING...AND CURRENT HEADLINES KEEP OUR NORTHWEST COUNTIES IN ONE
THROUGH 06Z MONDAY. TEMPERATURES WILL DROP INTO THE TEENS SUNDAY
EVENING...AND MAY FALL TO THE RANGE OF 10 TO 15 BY MONDAY MORNING.
WIND CHILLS IN THE TEENS SUNDAY WILL DROP TO THE -8 TO +5 RANGE BY
MONDAY MORNING. 2012 WILL CERTAINLY ENTER WITH A GOOD DOSE OF WINTER
TEMPERATURES...THIS COLD SNAP WILL BE OVER QUITE QUICKLY.
AFTER A COLD NIGHT MONDAY NIGHT...TUESDAY WILL BEGIN OUR NEXT WARM
UP...AS ZONAL FLOW DEVELOPS ALOFT. BY THURSDAY AND
FRIDAY...TEMPERATURES COULD EASILY REACH THE 50S IN MANY PARTS OF
THE CWA.
.ERVIN..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR
BENTON-CEDAR-CLINTON-DES MOINES-HENRY IA-IOWA-JACKSON-
JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-MUSCATINE-
SCOTT-VAN BUREN-WASHINGTON.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT
FOR BUCHANAN-DELAWARE-DUBUQUE.
IL...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR JO
DAVIESS-MERCER-ROCK ISLAND.
MO...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR CLARK-
SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
222 PM CST SAT DEC 31 2011
.SYNOPSIS...
300 HPA 12Z MAP ANALYSIS SHOWS A STRONG 140-145 KT JET EXTENDING ACROSS
THE PACIFIC NORTHWEST AND EASTWARDS ACROSS THE GREAT BASIN. AT 500 HPA,
STRONG COLD AIR ADVECTION WITH TEMPERATURES CHANGES IN THE 5 TO 10 DEGREE
C RANGE WERE NOTED IN COMPARING THE 00Z TO 12Z MAPS ACROSS THE ROCKIES.
THE COLDEST AIR AT 500 HPA - AROUND -35 DEG C - EXTENDED FROM BRITISH
COLUMBIA SOUTH INTO MONTANA. SIMILAR CHANGES IN TEMPERATURES WERE ALSO
NOTED AT 700 AND 750 HPA WELL UPSTREAM OF KANSAS. ACROSS THE PLAINS,
A WARM AND DRY PLUME PREVAILED AT 700/850 HPA. AT THE SURFACE, A COLD
FRONT WAS PUSHING ACROSS THE HIGH PLAINS WITH VERY STRONG WINDS (SEVERE,
IN FACT) WERE NOTED IN THE WAKE OF THE BOUNDARY. -SUGDEN
&&
.DISCUSSION...
DAYS 1-2...
NEW YEARS EVE:
SHORT TERM CONCERN IS WINDS. SEVERAL REPORTS OF 58+ MPH WINDS WERE NOTED
ACROSS NE COLORADO/NW KANSAS EARLY THIS AFTERNOON. HRRR GUIDANCE STILL
SUPPORTS WINDS (EITHER SUSTAINED OR GUSTS) MEETING WARNING CRITERIA
LATE THIS AFTERNOON AND INTO THE EARLY EVENING. WINDS SHOULD DECREASE
SIGNIFICANTLY IN THE 8-9 PM CST TIME RANGE. SECOND CONCERN WAS PRECIPITATION.
HAVE 15 POPS IN THE GRIDS AS COLD POOL MOVES ACROSS NORTH CENTRAL KANSAS
AND THERE COULD BE ENOUGH INSTABILITY FOR A FEW SHOWERS. HRRR FORECAST
COMPOSITE RADAR IMAGERY AS ALSO SUGGESTING AS SUCH. WITH THE EXCEPTION
OF CLOUDS ACROSS THE INTERSTATE 70 CORRIDOR, RELATIVELY CLEAR SKY CONDITIONS
ARE EXPECTED. TEMPERATURES OF UPPER TEENS DEG F WEST TO AROUND 30 DEG
F EAST ARE EXPECTED THROUGH THE OVERNIGHT HOURS.
NEW YEARS DAY:
COOLER TEMPERATURES BUT SEASONABLE OVERALL WILL RING IN NEW YEAR TOMORROW.
WITH THE AFOREMENTIONED STRONG COLD AIR ADVECTION, 850 HPA TEMPERATURES
WILL DECREASE TO THE -1 TO -2 DEG C RANGE. THIS SUPPORTS LOW 40S DEG
F ACROSS MUCH OF WEST CENTRAL AND SOUTHWEST KANSAS. THE EXCEPTION IS
TOWARDS SOUTH CENTRAL KANSAS WHERE A LARGER MIXING LAYER WILL SUPPORT
SURFACE TEMPERATURES IN THE UPPER 40S TO AROUND 50 DEG F. WITH DRY NORTHWEST
FLOW ALOFT PREVAILING IN THE WAKE OF A DEPARTING TROUGH, POPS WILL REMAIN
AT ZERO THROUGH THE FIRST DAY OF 2012.
SUNDAY EVENING:
STRONG HIGH PRESSURE OF AROUND 1040 HPA WILL SLIDE ACROSS THE PLAINS
OVERNIGHT SUNDAY. THIS WILL ALLOW FOR LIGHT WINDS. FORECAST SOUNDINGS
SHOW A FAIRLY DRY PROFILE, SO THINK A GOOD RADIATIONAL COOLING NIGHT
WILL OCCUR. LOW TEENS DEG F IS EXPECTED ACROSS THE NORTHWEST COUNTIES
TOWARDS SCOTT CITY WITH AROUND 20 DEG F EXPECTED TOWARDS MEDICINE LODGE.
AGAIN, NOT EXPECTING ANY PRECIPITATION WITH INCREASING 500 HPA ALOFT
AND HIGH PRESSURE AT THE SURFACE.
MONDAY:
500 HPA HEIGHTS OF AROUND 575-580 DM ARE EXPECTED MONDAY. SFC WINDS
WILL TURN MORE SOUTHERLY MONDAY AFTERNOON ON THE WESTERN SIDE OF THE
DEPARTING SURFACE HIGH. TEMPERATURES WILL REMAIN SEASONABLE MONDAY WITH
HIGHS IN THE 40S DEG F FOR MUCH OF SOUTHWEST KANSAS. WILL KEEP POPS
AT ZERO MONDAY WITH HIGH PRESSURE ALOFT/SUBSIDENCE OCCURRING ACROSS
WESTERN KANSAS. -SUGDEN
DAYS 3-7...
MUCH OF THE SENSIBLE WEATHER ACROSS SOUTHWEST KANSAS IN THE MEDIUM RANGE
WILL BE INFLUENCE BY SUBSTANTIAL RIDGING AS AN ANOMALOUS 585 DAM H5
HIGH BUILDS ACROSS THE SOUTHWEST. THIS WILL LEAD TO A FAIRLY SIGNIFICANT
WARMING OF THE LOWER TROPOSPHERE YIELDING HIGHS IN THE 50S TO LOWER
60S WEDNESDAY AND THURSDAY. BY THE END OF THE WEEK...THE GLOBAL MODELS
SUGGEST AN EROSION OF THE RIDGE WITH LOWERING HEIGHTS ACROSS THE NORTHWESTERN
CONUS. THE DETAILS OF THE PATTERN CHANGE ARE STILL RATHER UNCLEAR...BUT
AS WE HEAD INTO THE DAY 7 PORTION OF THIS FORECAST...THERE ARE SOME
SIGNALS IN THE GLOBAL MODELS (PARTICULARLY THE ECMWF) OF STORM DEVELOPMENT
OVER THE ROCKIES/PLAINS. FOR THIS UPDATE CYCLE...A DRY FORECAST IS
IN THE CARDS THROUGH SATURDAY. -UMSCHEID
&&
.AVIATION...
FOR THE 18Z TAF ISSUANCE...HIGH WIND EVENT WILL AFFECT GCK, DDC, HYS THIS
AFTERNOON THROUGH THIS EVENING. THE THINKING IS THAT THE PEAK OF THE
HIGH WIND EVENT WILL BE FROM ROUGHLY 21Z TO 00Z WHEN FREQUENT GUSTS
OF 45 TO 50 KNOTS CAN BE EXPECTED FROM THE NORTHWEST. A FEW SCATTERED
SHOWERS WILL LIKELY DEVELOP BEHIND THE LOW AFFECTING THE HYS TERMINAL
AND AS SUCH HAVE INSERTED VCSH EARLY THIS EVENING FOR A FEW HOURS.
THERE IS NOT EXPECTED TO BE A REDUCTION IN VISIBILITY/CEILING INTO
THE VFR CATEGORY...BUT SOME STRATUS WITH A 2000 TO 3000 FOOT CEILING
IS EXPECTED AT HYS AND PERHAPS DDC FOR A FEW HOURS. LATE TONIGHT
WINDS WILL DECREASE TO BELOW 15 KNOTS REMAINING OUT OF THE
NORTHWEST. -UMSCHEID
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 43 18 45 / 0 0 0 0
GCK 22 40 16 44 / 0 0 0 0
EHA 19 42 19 46 / 0 0 0 0
LBL 20 42 18 46 / 0 0 0 0
HYS 25 43 16 42 / 20 0 0 0
P28 28 49 21 45 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 9 PM CST /8 PM MST/ THIS EVENING FOR
KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
FN36/25/25
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1137 AM CST SAT DEC 31 2011
...UPDATE TO AVIATION...
.UPDATE...
HAVE UPDATED THE FORECAST THROUGH MIDNIGHT IN AN ATTEMPT TO NAIL
DOWN THE EXPECTED WIND GUSTS AND RH VALUES...ADJUST THE WIND
ADVISORY ACCORDINGLY...AND ADDRESS PRECIPITATION POTENTIAL.
THE WINDS WILL LIKELY BE THE MOST SIGNIFICANT IMPACT TODAY WITH
GUSTS TO AROUND 50 MPH ALREADY IN WESTERN KANSAS...60 MPH IN
WESTERN NEBRASKA...AND MORE THAN 100 MPH IN THE MOUNTAIN PASSES OF
COLORADO. THE STORM SYSTEM CAUSING THESE WINDS WILL TRACK TO THE
EAST THIS AFTERNOON AND EVENING...WITH A COLD FRONT EXPECTED TO
ENTER THE NORTHWESTERN CORNER OF THE FORECAST AREA JUST AFTER NOON
AND PASS THROUGH EAST CENTRAL KANSAS BY 6 PM. ALL MODEL GUIDANCE
THIS MORNING CONTINUES TO SUGGEST THE POTENTIAL FOR STRONG WINDS
TODAY...BUT THERE ARE NOW INDICATIONS THAT THESE WINDS WILL EXTEND
ACROSS THE ENTIRE FORECAST AREA...AND MAY BE STRONGER YET IN
NORTHERN PARTS OF THE FORECAST AREA. ALSO...SOUTHWEST WINDS AHEAD
OF THE FRONT WILL BE BORDERLINE ON MEETING WIND ADVISORY CRITERIA
SO HAVE INCLUDED THE ENTIRE AREA FROM NOON THROUGH 3 AM.
THE PRIMARY CONCERN IN THE NEAR TERM WILL THEN BE THE POTENTIAL
FOR GUSTS APPROACHING 60 MPH OR STRONGER DURING THE LATE AFTERNOON
AND EARLY EVENING HOURS. THERE IS ADMITTEDLY SOME MODERATE
POTENTIAL FOR THIS TO HAPPEN...PARTICULARLY IN THE CONCORDIA...
MARYSVILLE AND BELLEVILLE AREAS. NAM AND RUC SOUNDINGS ARE QUITE
AGGRESSIVE IN FORECASTING WINDS AT THE TOP OF THE MIXED LAYER IN
THE 50 TO 60 KT RANGE AT TIMES. IN ADDITION...THE ISALLOBARIC WIND
COMPONENT WILL BE SUBSTANTIAL WITH A FORECAST PRESSURE RISE/FALL
COUPLET APPROACHING 16 HPA ACROSS THE STATE OF KANSAS AND VERY
STRONG PRESSURE GRADIENT ALREADY IN PLACE. WILL BE CLOSELY
MONITORING THIS SYSTEM THROUGHOUT THE DAY FOR POTENTIAL HIGH WIND
WARNING ISSUANCE (FOR 50+ KNOT WINDS).
FURTHER COMPLICATING THIS FORECAST IS THE POTENTIAL FOR WIDESPREAD
CLOUD COVER AND SHOWERS. IN FACT...MODELS SUGGEST SOME INSTABILITY
AT THE TOP OF THE MIXED LAYER AND ABOVE 600 HPA WHICH COULD
EFFECTIVELY CREATE HEAVY ENOUGH SHOWERS TO BRING SOME OF THE
STRONGEST GUSTS DOWN TO THE SURFACE. ON THAT NOTE...THIS
INSTABILITY...POWERFUL SYSTEM DYNAMICS...AND A HIGHER QUALITY
MOISTURE POOL THAN PREVIOUSLY FORECAST SUGGEST THAT CHANCES FOR
SCATTERED SHOWERS ARE INCREASING...ESPECIALLY NORTH...AND COULD
NOT TOTALLY RULE OUT A FEW SNOW FLAKES OR EVEN A FEW LIGHTNING
STRIKES.
FIRE WEATHER ALSO REMAINS A CONCERN WITH SUCH POWERFUL WINDS. MIN
RH VALUES STILL APPEAR TO BE LIMITED TO AROUND 30 PERCENT...AND
SOME FUELS MAY BE LOCALLY MOIST GIVEN THE RECENT SNOW COVER IN
PARTS OF THE AREA. NEEDLESS TO SAY HOWEVER...WINDS AT 50+ MPH WILL
MAKE CONDITIONS DIFFICULT.
BARJENBRUCH
&&
.DISCUSSION...
PRIMARY ATTENTION IN FORECAST PERIOD IS WIND AND FIRE WEATHER
CONCERNS THIS AFTERNOON AND EVENING.
WIND CONCERNS: UPPER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE
INTO THE CENTRAL PLAINS THROUGHOUT THE DAY. STRENGTHENING PRESSURE
GRADIENT WILL RESULT IN STRONG SURFACE WINDS OVER MUCH OF THE CWA
TODAY. IN ADVANCE OF THE COLD FRONTAL PASSAGE...WINDS WILL INCREASE
TO 20-24 KTS OVER EAST CENTRAL KANSAS BY LATE MORNING. THIS CORRIDOR
OF STRONG WINDS WILL GRADUALLY SHIFT EASTWARD DURING THE EARLY
AFTERNOON HOURS AS THE SFC FRONT APPROACHES. ANTICIPATE SPEEDS TO BE
JUST UNDER WIND ADVISORY CRITERIA IN THIS AREA. BEHIND THE FRONTAL
PASSAGE...CONFIDENCE IS HIGHER THAT AREAS ALONG AND WEST OF A LINE
FROM HIAWATHA TO ABILENE WILL EXPERIENCE WIND SPEEDS GREATER THAN 25
KTS THIS AFTERNOON AND EVENING. IMMEDIATELY BEHIND THE BOUNDARY FROM
18-00Z...NEARLY DRY ADIABATIC LAPSE RATES WILL EXIST JUST ABOVE THE
SFC TO H8. APPROXIMATELY 2KFT AGL...40 KTS ARE EXPECTED...WITH WIND
DIRECTIONS FAIRLY UNIDIRECTIONAL THROUGH THE LOWEST 10KFT. 5 TO 8
HPA 3-HOUR PRESSURE RISES ARE EXPECTED BEHIND THE SFC TROUGH
AXIS...WITH CROSS-ISOBARIC FLOW OVER MUCH OF NC KANSAS AND 50
UBARS/KM MAGNITUDE DURING PEAK MIXING. THE END RESULT WILL BE A 3-6
HOUR WINDOW OF WIND ADVISORY CONDITIONS OVER PORTIONS OF NC/NE
KANSAS THIS AFTERNOON. ADDITIONALLY...HAVE SOME CONCERN THAT SHALLOW
CONVECTION COULD DEVELOP BEHIND THE FRONT ACROSS NORTHERN KANSAS.
WHILE THE PROBABILITY OF MEASURABLE RAINFALL ISN`T PARTICULARLY HIGH
DUE TO EVAPORATION...THE VIRGA MAY ALLOW FOR ENHANCED NEGATIVELY
BUOYANT WIND SPEEDS TO REACH THE SURFACE. THE AREA ALONG AND NORTH
OF A CONCORDIA TO SENECA LINE WILL HAVE THE GREATEST PROBABLY OF
SUCH A SCENARIO PLAYING OUT. BY EVENING...MIGHT SEE SOME AREAS WITH
LIGHT RAIN OVER THE NORTHERN CWA ON THE BACKSIDE OF THE LOW. AS A
SIDE NOTE...THE 06Z NAM CAME IN MUCH STRONGER WITH THE SYSTEM...WITH
AN AGGRESSIVE SCENARIO OF WIND ADV CONDITIONS OVER MUCH OF THE CWA
MUCH LATER THIS EVENING. CURRENTLY THIS IS AN OUTLIER BUT WILL NEED
TO MONITOR TRENDS ON SUBSEQUENT OPERATIONAL RUNS IF OTHER SOLUTIONS
BEGIN TO SUGGEST A MORE AGGRESSIVE SCENARIO.
FIRE WEATHER: STRONG WINDS...LOW RELATIVE HUMIDITY...WARM
TEMPERATURES AND DRY VEGETATION WILL MAKE FOR VERY HIGH FIRE DANGER
ACROSS THE AREA THIS AFTERNOON. THE CWA LOOKS TO FALL SHORT OF RED
FLAG CONDITIONS...WITH MINIMUM RELATIVE HUMIDITY VALUES AVERAGING IN
THE UPPER 20S TO LOWER 30S PERCENT RANGE. WILL NEED TO BE MONITORED
IF STRONGER MIXING YIELDS LOWER THAN ANTICIPATED DEWPOINTS. HIGHS
THIS AFTERNOON WILL RANGE FROM THE MIDDLE 50S IN NC KANSAS TO THE
MIDDLE 60S IN EC KANSAS. A FEW RECORD HIGHS MAY BE BROKEN TODAY IN
PORTIONS OF NE/EC KANSAS...TOPEKA`S RECORD SITS AT 63 FOR TODAY.
OTHERWISE IN THE FORECAST PERIOD...MUCH COOLER CONDITIONS ARE
EXPECTED TO START 2012. COLD AIR ADVECTION WILL HOLD TEMPERATURES IN
THE LOWER TO MIDDLE 40S ON SUNDAY AFTERNOON...WITH COLDER H85
TEMPERATURES ARRIVING ON MONDAY AS THE EASTERN TROUGH AMPLIFIES.
THIS WILL RESULT IN COOLER READINGS ON MONDAY...WITH HIGHS IN THE
MIDDLE TO UPPER 30S. THEREAFTER...TEMPERATURES WILL MODIFY THROUGH
THE REMAINDER OF THE WORK WEEK...WITH 50S RETURNING WED-FRI AS UPPER
LEVEL RIDGING BECOMES ESTABLISHED. WITH INITIAL NORTHWEST FLOW
ALOFT...TRANSITIONING TO A RIDGING PATTERN...THE LOWER ATMOSPHERE
WILL REMAIN QUITE DRY...RESULTING IN A DRY FORECAST FOR THE PERIOD.
BLAIR
&&
.AVIATION...
SOUTH TO SOUTHWEST WINDS GUSTING UP TO 30 KTS WILL PERSIST THROUGH
THE AFTERNOON IN ADVANCE OF A COLD FRONT. THE COLD FRONT WILL PASS
THROUGH MHK AROUND 00Z AND TOP/FOE CLOSE TO 01Z WITH A SHIFT TO
NORTHWEST WINDS. SIGNIFICANT GUSTS ARE POSSIBLE BEHIND THE COLD
FRONT WITH OCCASIONAL GUSTS OF 40 TO 45 KTS EXPECTED AND SOME
POTENTIAL FOR HIGHER GUSTS BETWEEN 00Z AND 06Z. THERE IS SOME
POTENTIAL FOR MVFR CIGS FOR A 2-4 HOUR PERIOD BETWEEN 00Z AND 06Z
AS WELL...BUT NOT CONFIDENT ENOUGH TO INCLUDE A TAF GROUP FOR THIS
JUST YET.
BARJENBRUCH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR KSZ008>012-020>024-026-
034>040-054>056-058-059.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1111 AM CST SAT DEC 31 2011
.UPDATE...
HAVE UPDATED THE FORECAST THROUGH MIDNIGHT IN AN ATTEMPT TO NAIL
DOWN THE EXPECTED WIND GUSTS AND RH VALUES...ADJUST THE WIND
ADVISORY ACCORDINGLY...AND ADDRESS PRECIPITATION POTENTIAL.
THE WINDS WILL LIKELY BE THE MOST SIGNIFICANT IMPACT TODAY WITH
GUSTS TO AROUND 50 MPH ALREADY IN WESTERN KANSAS...60 MPH IN
WESTERN NEBRASKA...AND MORE THAN 100 MPH IN THE MOUNTAIN PASSES OF
COLORADO. THE STORM SYSTEM CAUSING THESE WINDS WILL TRACK TO THE
EAST THIS AFTERNOON AND EVENING...WITH A COLD FRONT EXPECTED TO
ENTER THE NORTHWESTERN CORNER OF THE FORECAST AREA JUST AFTER NOON
AND PASS THROUGH EAST CENTRAL KANSAS BY 6 PM. ALL MODEL GUIDANCE
THIS MORNING CONTINUES TO SUGGEST THE POTENTIAL FOR STRONG WINDS
TODAY...BUT THERE ARE NOW INDICATIONS THAT THESE WINDS WILL EXTEND
ACROSS THE ENTIRE FORECAST AREA...AND MAY BE STRONGER YET IN
NORTHERN PARTS OF THE FORECAST AREA. ALSO...SOUTHWEST WINDS AHEAD
OF THE FRONT WILL BE BORDERLINE ON MEETING WIND ADVISORY CRITERIA
SO HAVE INCLUDED THE ENTIRE AREA FROM NOON THROUGH 3 AM.
THE PRIMARY CONCERN IN THE NEAR TERM WILL THEN BE THE POTENTIAL
FOR GUSTS APPROACHING 60 MPH OR STRONGER DURING THE LATE AFTERNOON
AND EARLY EVENING HOURS. THERE IS ADMITTEDLY SOME MODERATE
POTENTIAL FOR THIS TO HAPPEN...PARTICULARLY IN THE CONCORDIA...
MARYSVILLE AND BELLEVILLE AREAS. NAM AND RUC SOUNDINGS ARE QUITE
AGGRESSIVE IN FORECASTING WINDS AT THE TOP OF THE MIXED LAYER IN
THE 50 TO 60 KT RANGE AT TIMES. IN ADDITION...THE ISALLOBARIC WIND
COMPONENT WILL BE SUBSTANTIAL WITH A FORECAST PRESSURE RISE/FALL
COUPLET APPROACHING 16 HPA ACROSS THE STATE OF KANSAS AND VERY
STRONG PRESSURE GRADIENT ALREADY IN PLACE. WILL BE CLOSELY
MONITORING THIS SYSTEM THROUGHOUT THE DAY FOR POTENTIAL HIGH WIND
WARNING ISSUANCE (FOR 50+ KNOT WINDS).
FURTHER COMPLICATING THIS FORECAST IS THE POTENTIAL FOR WIDESPREAD
CLOUD COVER AND SHOWERS. IN FACT...MODELS SUGGEST SOME INSTABILITY
AT THE TOP OF THE MIXED LAYER AND ABOVE 600 HPA WHICH COULD
EFFECTIVELY CREATE HEAVY ENOUGH SHOWERS TO BRING SOME OF THE
STRONGEST GUSTS DOWN TO THE SURFACE. ON THAT NOTE...THIS
INSTABILITY...POWERFUL SYSTEM DYNAMICS...AND A HIGHER QUALITY
MOISTURE POOL THAN PREVIOUSLY FORECAST SUGGEST THAT CHANCES FOR
SCATTERED SHOWERS ARE INCREASING...ESPECIALLY NORTH...AND COULD
NOT TOTALLY RULE OUT A FEW SNOW FLAKES OR EVEN A FEW LIGHTNING
STRIKES.
FIRE WEATHER ALSO REMAINS A CONCERN WITH SUCH POWERFUL WINDS. MIN
RH VALUES STILL APPEAR TO BE LIMITED TO AROUND 30 PERCENT...AND
SOME FUELS MAY BE LOCALLY MOIST GIVEN THE RECENT SNOW COVER IN
PARTS OF THE AREA. NEEDLESS TO SAY HOWEVER...WINDS AT 50+ MPH WILL
MAKE CONDITIONS DIFFICULT.
BARJENBRUCH
&&
.DISCUSSION...
PRIMARY ATTENTION IN FORECAST PERIOD IS WIND AND FIRE WEATHER
CONCERNS THIS AFTERNOON AND EVENING.
WIND CONCERNS: UPPER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE
INTO THE CENTRAL PLAINS THROUGHOUT THE DAY. STRENGTHENING PRESSURE
GRADIENT WILL RESULT IN STRONG SURFACE WINDS OVER MUCH OF THE CWA
TODAY. IN ADVANCE OF THE COLD FRONTAL PASSAGE...WINDS WILL INCREASE
TO 20-24 KTS OVER EAST CENTRAL KANSAS BY LATE MORNING. THIS CORRIDOR
OF STRONG WINDS WILL GRADUALLY SHIFT EASTWARD DURING THE EARLY
AFTERNOON HOURS AS THE SFC FRONT APPROACHES. ANTICIPATE SPEEDS TO BE
JUST UNDER WIND ADVISORY CRITERIA IN THIS AREA. BEHIND THE FRONTAL
PASSAGE...CONFIDENCE IS HIGHER THAT AREAS ALONG AND WEST OF A LINE
FROM HIAWATHA TO ABILENE WILL EXPERIENCE WIND SPEEDS GREATER THAN 25
KTS THIS AFTERNOON AND EVENING. IMMEDIATELY BEHIND THE BOUNDARY FROM
18-00Z...NEARLY DRY ADIABATIC LAPSE RATES WILL EXIST JUST ABOVE THE
SFC TO H8. APPROXIMATELY 2KFT AGL...40 KTS ARE EXPECTED...WITH WIND
DIRECTIONS FAIRLY UNIDIRECTIONAL THROUGH THE LOWEST 10KFT. 5 TO 8
HPA 3-HOUR PRESSURE RISES ARE EXPECTED BEHIND THE SFC TROUGH
AXIS...WITH CROSS-ISOBARIC FLOW OVER MUCH OF NC KANSAS AND 50
UBARS/KM MAGNITUDE DURING PEAK MIXING. THE END RESULT WILL BE A 3-6
HOUR WINDOW OF WIND ADVISORY CONDITIONS OVER PORTIONS OF NC/NE
KANSAS THIS AFTERNOON. ADDITIONALLY...HAVE SOME CONCERN THAT SHALLOW
CONVECTION COULD DEVELOP BEHIND THE FRONT ACROSS NORTHERN KANSAS.
WHILE THE PROBABILITY OF MEASURABLE RAINFALL ISN`T PARTICULARLY HIGH
DUE TO EVAPORATION...THE VIRGA MAY ALLOW FOR ENHANCED NEGATIVELY
BUOYANT WIND SPEEDS TO REACH THE SURFACE. THE AREA ALONG AND NORTH
OF A CONCORDIA TO SENECA LINE WILL HAVE THE GREATEST PROBABLY OF
SUCH A SCENARIO PLAYING OUT. BY EVENING...MIGHT SEE SOME AREAS WITH
LIGHT RAIN OVER THE NORTHERN CWA ON THE BACKSIDE OF THE LOW. AS A
SIDE NOTE...THE 06Z NAM CAME IN MUCH STRONGER WITH THE SYSTEM...WITH
AN AGGRESSIVE SCENARIO OF WIND ADV CONDITIONS OVER MUCH OF THE CWA
MUCH LATER THIS EVENING. CURRENTLY THIS IS AN OUTLIER BUT WILL NEED
TO MONITOR TRENDS ON SUBSEQUENT OPERATIONAL RUNS IF OTHER SOLUTIONS
BEGIN TO SUGGEST A MORE AGGRESSIVE SCENARIO.
FIRE WEATHER: STRONG WINDS...LOW RELATIVE HUMIDITY...WARM
TEMPERATURES AND DRY VEGETATION WILL MAKE FOR VERY HIGH FIRE DANGER
ACROSS THE AREA THIS AFTERNOON. THE CWA LOOKS TO FALL SHORT OF RED
FLAG CONDITIONS...WITH MINIMUM RELATIVE HUMIDITY VALUES AVERAGING IN
THE UPPER 20S TO LOWER 30S PERCENT RANGE. WILL NEED TO BE MONITORED
IF STRONGER MIXING YIELDS LOWER THAN ANTICIPATED DEWPOINTS. HIGHS
THIS AFTERNOON WILL RANGE FROM THE MIDDLE 50S IN NC KANSAS TO THE
MIDDLE 60S IN EC KANSAS. A FEW RECORD HIGHS MAY BE BROKEN TODAY IN
PORTIONS OF NE/EC KANSAS...TOPEKA`S RECORD SITS AT 63 FOR TODAY.
OTHERWISE IN THE FORECAST PERIOD...MUCH COOLER CONDITIONS ARE
EXPECTED TO START 2012. COLD AIR ADVECTION WILL HOLD TEMPERATURES IN
THE LOWER TO MIDDLE 40S ON SUNDAY AFTERNOON...WITH COLDER H85
TEMPERATURES ARRIVING ON MONDAY AS THE EASTERN TROUGH AMPLIFIES.
THIS WILL RESULT IN COOLER READINGS ON MONDAY...WITH HIGHS IN THE
MIDDLE TO UPPER 30S. THEREAFTER...TEMPERATURES WILL MODIFY THROUGH
THE REMAINDER OF THE WORK WEEK...WITH 50S RETURNING WED-FRI AS UPPER
LEVEL RIDGING BECOMES ESTABLISHED. WITH INITIAL NORTHWEST FLOW
ALOFT...TRANSITIONING TO A RIDGING PATTERN...THE LOWER ATMOSPHERE
WILL REMAIN QUITE DRY...RESULTING IN A DRY FORECAST FOR THE PERIOD.
BLAIR
&&
.AVIATION...
RELATIVELY DRY AIR IN THE LOWER ATMOSPHERE IS EXPECTED TO CREATE VFR
CONDITIONS TODAY. MAIN CONCERN WILL BE WINDS WITH THE PRESSURE
GRADIENT INCREASE THROUGH THE DAY. GUSTS UP TO 35 KTS ARE EXPECTED
TO PERSIST WELL AFTER SUNSET BECAUSE OF THE PRESSURE GRADIENT AND A
STRONG LOW LEVEL JET MOVING IN FROM THE NORTHWEST. THE GFS AND NAM
ARE STARTING TO HINT AT A BRIEF CLOUD DECK COMING IN BEHIND THE
FRONT BETWEEN 2 AND 3 KFT. OPTED TO KEEP AN OPTIMISTIC FORECAST AND
LET THE NEXT SHIFTS SEE IF THIS PANS OUT.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR KSZ008>012-020>024-026-
034>040-054>056-058-059.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EST SAT DEC 31 2011
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.UPDATE...ISSUED AT 1138 AM EST SAT DEC 31 2011...
DIDN/T MAKE ANY CHANGES TO THE GOING HEADLINES...BUT THERE MAY BE
SOME CHANGES NEEDED AS THE LATEST 12Z MODELS RUNS HAVE BEEN
ARRIVING. 12Z RUNS THAT HAVE ARRIVED SO FAR HAVE SHOWN THE H850-600
FGEN FORCED PCPN HANGING UP FARTHER WEST OVER WRN LK SUPERIOR THIS
EVENING AND THEN PUSHING INTO GOGEBIC/ONTONAGON COUNTIES TOWARDS
MIDNIGHT AND THEN CONTINUING INTO SUN MORNING. THUS...GOING WARNING
LOOKS GOOD THERE. CONCERN ARRIVES FOR NRN HOUGHTON/KEWEENAW...ALONG
WITH BARAGA/MARQUETTE COUNTIES FOR TONIGHT. TRENDS FOR TONIGHT HAVE
SNOWS STAYING FAIRLY LIGHT...WITH ONLY AN INCH OR TWO OF
ACCUMULATION AFTER MIDNIGHT FOR THE KEWEENAW AND TOWARDS MORNING FOR
MARQUETTE/BARAGA AS THE SHORTWAVE BEGINS TO ROTATE NE AND
STRENGTHENS THE LOW. WILL TAKE A CLOSER LOOK INTO WHAT TO DO FOR
TONIGHT/S HEADLINES...BUT WILL CONTINUE TO EMPHASIZE THE NEAR
BLIZZARD CONDITIONS FOR SUN AFTN INTO MON. LATEST TRENDS ARE ALSO
SHOWING ADVY SNOW FOR DICKINSON/MENOMINEE/DELTA/SRN SCHOOLCRAFT AND
WILL LIKELY NEED AT LEAST ADVY...BUT WINDS AND BLOWING SNOW COULD
SUPPORT WARNING THERE FOR TOMORROW MORNING...BUT WANT TO SEE MOST OF
THE 12Z RUNS BEFORE GOING WITH AT LEAST AN ADVY.
&&
.SYNOPSIS...ISSUED AT 750 AM EST SAT DEC 31 2011...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW
PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS
SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF
NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS
AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH
COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A
FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER
VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR
RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT...
BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON
THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP
SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN
LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE
AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN
INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS
HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV
IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER
200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS
ACCOMPANIED BY SN STRUCK NEAR BOISE ID.
&&
.DISCUSSION...ISSUED AT 750 AM EST SAT DEC 31 2011...
MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN
STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR
UPR MI BY SUN.
TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN
THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD
OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS
MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL
MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E
NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST
TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH
DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW
AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA
WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW
GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS
TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP.
EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S
WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN
THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT
PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP
COOLING.
TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC
LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH
DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK
OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER
NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS
SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER
12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE
2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH
SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN
TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR
DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE
LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT
ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO
IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL
ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C
NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN
WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING
SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT
THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE
PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE.
SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH
THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR
MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z
MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC
BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS...
WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK
SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE
E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT
APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF
FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS
PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF...
SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME
ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE
ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU
THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND
SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED
SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT
-SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS
LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES
TNGT.
MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME
WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z
ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY...
MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE
SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR
DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND
06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE
RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/
LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO
SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER
AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS
WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL.
AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO
WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD
AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH
GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE
3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z
PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD
CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT
LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE
BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY
NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF
BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT
MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH
SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN
AFTN INTO MON NGT.
FOR THE EXTENDED FORECAST...
FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND
OF AVAILABLE MODEL DATA.
STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP
OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A
SIGNIFICANT RIDGE BUILDING OVERHEAD.
THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE
TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE
CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR
DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE
OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE
LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF
THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS.
THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE
GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER
TO 12Z WEDNESDAY.
STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY
THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN
RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A
SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT
FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA
FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR
FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT
SYSTEM...DUE TO THE MODERATE CONFIDENCE.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
LOW PRESSURE SYSTEM DEVELOPING IN THE NRN/CNTRL PLAINS WILL BRING
DETERIORATING CONDITIONS AT THE TAF SITES THIS EVENING THROUGH THE
END OF THE TAF PERIOD. AREA OF LOW CLOUDS AND FOG IN CNTRL WI WILL
SLOWLY ADVECT NORTH LATE THIS AFTN AND EVENING AND LEAD TO LOW END
MVFR CIGS AT ALL SITES THROUGH THE EVENING. KSAW HAS THE BEST CHANCE
OF SEEING FOG THIS EVENING AND COULD GO LOWER THAN FCST WITH THE
FAVORABLE SSE UPSLOPE WINDS...BUT THINK WINDS WILL BE STRONG ENOUGH
TO KEEP VSBY FROM GOING TOO LOW. OTHERWISE...-SN WILL DEVELOP THIS
EVENING AT KIWD AND SLOWLY SHIFT E THROUGH THE NIGHT. VSBYS SHOULD
BE BELOW ALT LANDING MINS FOR THE SITES IN THE STRONGEST SNOW BAND
THAT AFFECTS EACH OF THE SITES OVERNIGHT INTO SUN MORNING.
INCREASING NW WINDS ON SUN...WITH GUSTS APPROACHING 40KTS BY THE END
OF THE TAF PERIOD AT KCMX/KSAW...WILL LEAD TO CONSIDERABLE
BLOWING/DRIFTING SNOW AND PUT VSBYS NEAR AIRFIELD LANDING MINS.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD
TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA
THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM
SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE
KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF
STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A
RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE
WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE
RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE
TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL
CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON
BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7
PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT
FOR MIZ006-007-085.
WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR
MIZ004-005.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
MONDAY FOR MIZ010.
LAKE SUPERIOR...
STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY
MORNING FOR LSZ162-263>267.
STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ248>251.
STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR
LSZ243>247.
STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6
AM CST/ MONDAY FOR LSZ241-242.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM
CST/ MONDAY FOR LSZ240.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON
CST/ MONDAY FOR LSZ162.
STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248-
250.
&&
$$
UPDATE...SRF
SYNOPSIS...KC
DISCUSSION...KC
EXTENDED...KF
AVIATION...SRF
MARINE...KF
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1138 AM EST SAT DEC 31 2011
.UPDATE...
DIDN/T MAKE ANY CHANGES TO THE GOING HEADLINES...BUT THERE MAY BE
SOME CHANGES NEEDED AS THE LATEST 12Z MODELS RUNS HAVE BEEN
ARRIVING. 12Z RUNS THAT HAVE ARRIVED SO FAR HAVE SHOWN THE H850-600
FGEN FORCED PCPN HANGING UP FARTHER WEST OVER WRN LK SUPERIOR THIS
EVENING AND THEN PUSHING INTO GOGEBIC/ONTONAGON COUNTIES TOWARDS
MIDNIGHT AND THEN CONTINUING INTO SUN MORNING. THUS...GOING WARNING
LOOKS GOOD THERE. CONCERN ARRIVES FOR NRN HOUGHTON/KEWEENAW...ALONG
WITH BARAGA/MARQUETTE COUNTIES FOR TONIGHT. TRENDS FOR TONIGHT HAVE
SNOWS STAYING FAIRLY LIGHT...WITH ONLY AN INCH OR TWO OF
ACCUMULATION AFTER MIDNIGHT FOR THE KEWEENAW AND TOWARDS MORNING FOR
MARQUETTE/BARAGA AS THE SHORTWAVE BEGINS TO ROTATE NE AND
STRENGTHENS THE LOW. WILL TAKE A CLOSER LOOK INTO WHAT TO DO FOR
TONIGHT/S HEADLINES...BUT WILL CONTINUE TO EMPHASIZE THE NEAR
BLIZZARD CONDITIONS FOR SUN AFTN INTO MON. LATEST TRENDS ARE ALSO
SHOWING ADVY SNOW FOR DICKINSON/MENOMINEE/DELTA/SRN SCHOOLCRAFT AND
WILL LIKELY NEED AT LEAST ADVY...BUT WINDS AND BLOWING SNOW COULD
SUPPORT WARNING THERE FOR TOMORROW MORNING...BUT WANT TO SEE MOST OF
THE 12Z RUNS BEFORE GOING WITH AT LEAST AN ADVY.
&&
PREV DISCUSSION...ISSUED AT 750 AM EST SAT DEC 31 2011...
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW
PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS
SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF
NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS
AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH
COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A
FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER
VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR
RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT...
BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON
THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP
SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN
LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE
AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN
INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS
HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV
IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER
200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS
ACCOMPANIED BY SN STRUCK NEAR BOISE ID.
&&
.DISCUSSION...
MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN
STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR
UPR MI BY SUN.
TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN
THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD
OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS
MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL
MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E
NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST
TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH
DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW
AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA
WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW
GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS
TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP.
EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S
WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN
THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT
PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP
COOLING.
TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC
LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH
DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK
OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER
NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS
SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER
12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE
2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH
SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN
TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR
DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE
LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT
ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO
IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL
ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C
NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN
WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING
SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT
THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE
PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE.
SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH
THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR
MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z
MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC
BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS...
WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK
SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE
E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT
APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF
FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS
PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF...
SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME
ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE
ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU
THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND
SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED
SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT
-SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS
LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES
TNGT.
MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME
WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z
ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY...
MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE
SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR
DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND
06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE
RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/
LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO
SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER
AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS
WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL.
AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO
WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD
AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH
GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE
3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z
PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD
CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT
LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE
BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY
NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF
BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT
MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH
SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN
AFTN INTO MON NGT.
FOR THE EXTENDED FORECAST...
FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND
OF AVAILABLE MODEL DATA.
STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP
OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A
SIGNIFICANT RIDGE BUILDING OVERHEAD.
THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE
TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE
CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR
DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE
OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE
LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF
THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS.
THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE
GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER
TO 12Z WEDNESDAY.
STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY
THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN
RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A
SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT
FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA
FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR
FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT
SYSTEM...DUE TO THE MODERATE CONFIDENCE.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
EXPECT INCREASING SOUTHERLY WINDS TODAY...OUT AHEAD OF AN
APPROACHING LOW ACROSS THE NORTHERN PLAINS. ALTHOUGH THE SPECIFIC
TIMING AND TRACK OF THIS LOW REMAINS A BIT UNCERTAIN...IT SHOULD
SLIDE ACROSS CENTRAL/NORTHERN LAKE MICHIGAN DURING THE DAYLIGHT
HOURS SUNDAY MORNING. AT THIS TIME IT STILL LOOKS REASONABLE FOR IWD
AND CMX TO FALL TO IFR AROUND 02/03Z AS THE TROUGH CROSSES AND
COLDER AIR AOB -3C RUSHES IN /WITH LOW PRESSURE EXTENDING FROM
ONTARIO THROUGH SW WISCONSIN AROUND 03Z/. THIS SHOULD TIME OUT FOR
07Z FOR SIMILAR CONDITIONS AT SAW...BEFORE WINDS BEGIN TO PICK UP
TOWARD SUNRISE SUNDAY AT IWD AND SAW...WITH BLSN LIKELY NEEDING TO
BE ADDED TO THE TAFS WITH THE NEXT UPDATE/AMENDMENT. AS NOTED IN THE
PREVIOUS DISCUSSION WITH CONTINUED STRONG N-NW FLOW AT CMX...ADVERSE
CONDITIONS AT OR BLO AIRPORT MINS SHOULD CONTINUE INTO MONDAY.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD
TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA
THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM
SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE
KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF
STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A
RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE
WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE
RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE
TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL
CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON
BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7
PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT
FOR MIZ006-007-085.
WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR
MIZ004-005.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
MONDAY FOR MIZ010.
LAKE SUPERIOR...
STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY
MORNING FOR LSZ162-263>267.
STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ248>251.
STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR
LSZ243>247.
STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6
AM CST/ MONDAY FOR LSZ241-242.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM
CST/ MONDAY FOR LSZ240.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON
CST/ MONDAY FOR LSZ162.
STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248-
250.
&&
$$
UPDATE...SRF
SYNOPSIS...KC
DISCUSSION...KC
EXTENDED...KF
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
750 AM EST SAT DEC 31 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW
PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS
SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF
NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS
AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH
COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A
FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER
VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR
RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT...
BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON
THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP
SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN
LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE
AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN
INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS
HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV
IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER
200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS
ACCOMPANIED BY SN STRUCK NEAR BOISE ID.
&&
.DISCUSSION...
MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN
STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR
UPR MI BY SUN.
TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN
THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD
OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS
MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL
MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E
NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST
TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH
DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW
AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA
WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW
GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS
TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP.
EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S
WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN
THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT
PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP
COOLING.
TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC
LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH
DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK
OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER
NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS
SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER
12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE
2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH
SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN
TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR
DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE
LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT
ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO
IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL
ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C
NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN
WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING
SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT
THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE
PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE.
SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH
THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR
MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z
MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC
BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS...
WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK
SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE
E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT
APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF
FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS
PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF...
SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME
ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE
ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU
THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND
SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED
SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT
-SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS
LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES
TNGT.
MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME
WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z
ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY...
MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE
SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR
DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND
06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE
RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/
LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO
SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER
AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS
WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL.
AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO
WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD
AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH
GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE
3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z
PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD
CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT
LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE
BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY
NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF
BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT
MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH
SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN
AFTN INTO MON NGT.
FOR THE EXTENDED FORECAST...
FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND
OF AVAILABLE MODEL DATA.
STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP
OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A
SIGNIFICANT RIDGE BUILDING OVERHEAD.
THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE
TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE
CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR
DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE
OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE
LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF
THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS.
THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE
GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER
TO 12Z WEDNESDAY.
STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY
THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN
RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A
SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT
FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA
FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR
FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT
SYSTEM...DUE TO THE MODERATE CONFIDENCE.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
EXPECT INCREASING SOUTHERLY WINDS TODAY...OUT AHEAD OF AN
APPROACHING LOW ACROSS THE NORTHERN PLAINS. ALTHOUGH THE SPECIFIC
TIMING AND TRACK OF THIS LOW REMAINS A BIT UNCERTAIN...IT SHOULD
SLIDE ACROSS CENTRAL/NORTHERN LAKE MICHIGAN DURING THE DAYLIGHT
HOURS SUNDAY MORNING. AT THIS TIME IT STILL LOOKS REASONABLE FOR IWD
AND CMX TO FALL TO IFR AROUND 02/03Z AS THE TROUGH CROSSES AND
COLDER AIR AOB -3C RUSHES IN /WITH LOW PRESSURE EXTENDING FROM
ONTARIO THROUGH SW WISCONSIN AROUND 03Z/. THIS SHOULD TIME OUT FOR
07Z FOR SIMILAR CONDITIONS AT SAW...BEFORE WINDS BEGIN TO PICK UP
TOWARD SUNRISE SUNDAY AT IWD AND SAW...WITH BLSN LIKELY NEEDING TO
BE ADDED TO THE TAFS WITH THE NEXT UPDATE/AMENDMENT. AS NOTED IN THE
PREVIOUS DISCUSSION WITH CONTINUED STRONG N-NW FLOW AT CMX...ADVERSE
CONDITIONS AT OR BLO AIRPORT MINS SHOULD CONTINUE INTO MONDAY.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD
TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA
THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM
SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE
KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF
STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A
RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE
WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE
RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE
TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL
CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON
BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7
PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT
FOR MIZ006-007-085.
WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR
MIZ004-005.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
MONDAY FOR MIZ010.
LAKE SUPERIOR...
STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY
MORNING FOR LSZ162-263>267.
STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ248>251.
STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR
LSZ243>247.
STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6
AM CST/ MONDAY FOR LSZ241-242.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM
CST/ MONDAY FOR LSZ240.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON
CST/ MONDAY FOR LSZ162.
STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248-
250.
&&
$$
SYNOPSIS...KC
DISCUSSION...KC
EXTENDED...KF
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
532 AM EST SAT DEC 31 2011
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW
PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS
SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF
NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS
AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH
COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A
FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER
VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR
RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT...
BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON
THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP
SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN
LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE
AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN
INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS
HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV
IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER
200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS
ACCOMPANIED BY SN STRUCK NEAR BOISE ID.
&&
.DISCUSSION...
MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN
STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR
UPR MI BY SUN.
TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN
THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD
OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS
MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL
MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E
NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST
TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH
DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW
AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA
WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW
GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS
TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP.
EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S
WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN
THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT
PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP
COOLING.
TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC
LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH
DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK
OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER
NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS
SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER
12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE
2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH
SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN
TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR
DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE
LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT
ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO
IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL
ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C
NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN
WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING
SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT
THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE
PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE.
SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH
THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR
MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z
MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC
BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS...
WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK
SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE
E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT
APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF
FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS
PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF...
SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME
ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE
ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU
THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND
SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED
SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT
-SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS
LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES
TNGT.
MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME
WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z
ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY...
MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE
SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR
DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND
06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE
RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/
LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO
SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER
AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS
WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL.
AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO
WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD
AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH
GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE
3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z
PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD
CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT
LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE
BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY
NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF
BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT
MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH
SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN
AFTN INTO MON NGT.
FOR THE EXTENDED FORECAST...
FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND
OF AVAILABLE MODEL DATA.
STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP
OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A
SIGNIFICANT RIDGE BUILDING OVERHEAD.
THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE
TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE
CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR
DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE
OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE
LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF
THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS.
THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE
GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER
TO 12Z WEDNESDAY.
STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY
THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN
RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A
SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT
FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA
FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR
FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT
SYSTEM...DUE TO THE MODERATE CONFIDENCE.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
LIGHT/VRB WIND REGIME WILL BECOME SOUTHERLY OVERNIGHT INTO THE
MORNING HRS. AS IT DOES...LOWER CLOUDS (MAINLY MVFR) AT
KIWD/KCMX/KSAW WILL SCATTER OUT WITH VFR CONDITIONS THEN FOLLOWING
THRU THE DAY. BEFORE THAT HAPPENS...THERE ARE CURRENTLY LOWER IFR
CIGS TRYING TO SPREAD W FROM ERN UPPER MI. THESE CLOUDS MAY REACH
KSAW...SO HAVE INCLUDED AN IFR CIG INTO THE EARLY MORNING HRS.
ALSO...WHERE CLOUDS SCATTER OUT FOR A WHILE...FOG MAY DEVELOP AND
POTENTIALLY DROP VIS TO IFR OR LOWER. WITH LOW CONFIDENCE IN DENSE
FOG DEVELOPMENT...DID NOT DROP VIS BLO MVFR. NEXT LOW PRES SYSTEM
ORGANIZING OVER THE CNTRL/NRN PLAINS TODAY WILL DEEPEN AS IT TRACKS
ACROSS THE UPPER GREAT LAKES TONIGHT/EARLY SUN. INCREASING WIND
FIELDS WILL RESULT IN A PERIOD OF LLWS AT KCMX IN THE EVENING. SFC
WINDS SHOULD REMAIN GUSTY AT KIWD/KSAW...SO DID NOT INCLUDE LLWS AT
THOSE SITES. SNOW WILL SPREAD TO KIWD/KCMX MID TO LATE EVENING WITH
CONDITIONS QUICKLY FALLING TO IFR.
OUTLOOK...DEEPENING LOW PRES WILL PASS ACROSS THE UPPER GREAT LAKES
LATE TONIGHT/SUN MORNING. DUE TO STRONG NORTHWESTERLY WINDS AND
MDT/HEAVY LAKE EFFECT SNOW BEHIND THE LOW...FLYING CONDITIONS ARE
EXPECTED TO BECOME VERY POOR NEW YEARS DAY. ADVERSE CONDITIONS...
PROBABLY AT OR BLO AIRPORT MINS AT KCMX...SHOULD CONTINUE INTO MON.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD
TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA
THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM
SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE
KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF
STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A
RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE
WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE
RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE
TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL
CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON
BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7
PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT
FOR MIZ006-007-085.
WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR
MIZ004-005.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
MONDAY FOR MIZ010.
LAKE SUPERIOR...
STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY
MORNING FOR LSZ162-263>267.
STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR
LSZ248>251.
STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR
LSZ243>247.
STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6
AM CST/ MONDAY FOR LSZ241-242.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM
CST/ MONDAY FOR LSZ240.
GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON
CST/ MONDAY FOR LSZ162.
STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248-
250.
&&
$$
SYNOPSIS...KC
DISCUSSION...KC
EXTENDED...KF
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
243 PM CST SAT DEC 31 2011
.DISCUSSION...
IT LOOKS LIKE THE BEST WINDS ARE PASSING SOUTH AND WEST OF THE
FCST AREA THIS AFTERNOON. THE PV15 PRESSURE SFC IS NOTICEABLY
FARTHER SOUTH ON SATELLITE AND IN THE RUC THAN PREVIOUS MODEL
SOLNS SUGGESTED. IT APPEARS THE ENTIRE WIND FIELD HAS SHIFTED
SOUTHWEST ACROSS THE FAR SRN NEB PANHANDLE...NERN COLO AND WRN KS. THUS
THE HIGH WIND WARNING AND PARTS OF THE WIND ADVISORY MAY BE
CANCELLED EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING.
THE MODELS ALSO MOVE A PRETTY GOOD AREA OF RAIN AND SNOW FARTHER
SOUTH THROUGH SWRN NEB. THIS PCPN SHOULD EXIT THE FCST AREA BY
AROUND 03Z ACCORDING TO THE HRRR WHICH HAS SHOWN GOOD SKILL TODAY
WITH PCPN FCSTS BUT NOT HIGH WIND GUSTS WHICH NEVER MATERIALIZED
AS EXPECTED.
GENERALLY CLEAR SKIES ARE EXPECTED AREA WIDE BY ROUGHLY 03Z-06Z
AND STRONG PACIFIC HIGH PRESSURE WILL BUILD SLOWLY INTO THE NRN
AND CNTL PLAINS SUNDAY. ANOTHER WINDY DAY IS EXPECTED ALONG AND
EAST OF HIGHWAY 83 AND THE BEST GUESS USING MET/MAV GUIDANCE AND
500M AGL WINDS IS SPEEDS WILL BE 25 TO 30 MPH WITH GUSTS TO 40
MPH...JUST BELOW WIND ADVISORY CRITERIA.
PACIFIC HIGH PRESSURE WILL STRENGTHEN DIRECTLY ACROSS THE FCST
AREA SUNDAY NIGHT AND MONDAY MORNING PRODUCING LOWS IN THE SINGLE
DIGITS IN MANY AREAS. THIS HIGH WILL MOVE SOUTH AND EAST MONDAY
WITH A NEW LOW PRESSURE TROF DEVELOPING ACROSS THE NRN HIGH
PLAINS. THIS TROF MOVES EAST TUESDAY WITH A WARMING TREND AND
HIGHS IN THE 40S TO NEAR 50.
.LONG TERM...
WEDNESDAY THROUGH SATURDAY. AN UPPER LEVEL RIDGE OF HIGH
PRESSURE WILL TRANSLATE EAST FROM THE ROCKIES INTO THE CENTRAL
PLAINS DURING THE PERIOD. THIS WILL KEEP THE MILD AND MAINLY DRY
WEATHER PATTERN IN PLACE. MODELS CONTINUE TO AGREE THAT THURSDAY
WILL BE THE WARMEST DAY...AS 850 MB TEMPERATURES OF +15C COMBINE
WITH A WESTERLY DOWNSLOPE WIND AND BRING POSSIBLE RECORD HIGHS /IN
THE 60S/ TO PARTS OF THE AREA. MODELS AGREE THAT A COLD FRONT WILL
BRING COOLER WEATHER TO THE AREA FRIDAY AND SATURDAY AS A TROUGH OF
LOW PRESSURE DEVELOPS ACROSS THE WESTERN CONUS.
&&
.AVIATION...
PRECIPITATION IN THE FORM OF RAIN AND SNOW...WILL
GRADUALLY END BY LATE AFTERNOON. THROUGH 23Z HOWEVER...VSBY MAY
LOCALLY BE REDUCED TO 1/2 MILE AND IFR CONDITIONS IN HEAVIER SNOW
ALONG A LINE FROM KAIA TO KOGA TO KLBF. OTHERWISE MOSTLY MVFR OR VFR
EXPECTED. GUSTY NORTHWEST WINDS OF 25 TO 35 KTS CAN ALSO BE
EXPECTED. RAPIDLY IMPROVING CONDITIONS SHOULD OCCUR THIS EVENING AS
WINDS AND CLOUDS DECREASE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...HIGH WIND WARNING UNTIL 9 PM
CST /8 PM MST/ THIS EVENING FOR NEZ004-022-023-035-056>059-069>071.
WIND ADVISORY UNTIL 9 PM CST /8 PM MST/ THIS EVENING FOR
NEZ005>010-024>029-036>038-094.
&&
$$
SHORT TERM...CDC
AVIATION/EXTENDED...TAYLOR
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
630 PM EST SUN JAN 1 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT. ARCTIC
HIGH PRESSURE BEHIND THE FRONT WILL GRADUALLY BUILD EAST AND
BECOME CENTERED OVER THE AREA WEDNESDAY. THE HIGH WILL PASS
OFFSHORE SOUTH OF THE AREA THURSDAY THROUGH SATURDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTHWEST NEXT SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 630 PM SUNDAY...COLD FRONT MOVING INTO THE WESTERN PIEDMONT
REGION AS OF 23Z AND SHOULD CONTINUE ACROSS EASTERN NORTH CAROLINA
AND OFFSHORE BY THE EARLY MORNING HOURS. MESOSCALE ANALYSIS SHOWS
DECENT H8 MOISTURE TRANSPORT INTO EASTERN NC WITH A SLIGHT
INCREASE IN PRECIPITABLE WATER VALUES. COMPOSITE REGIONAL RADAR
DOES SHOW A BAND OF LIGHT SHOWERS CROSSING THE NORTHERN PORTION OF
THE PIEDMONT AND A FEW OF THESE COULD HOLD TOGETHER INTO THE MHX
CWA SO HAVE A SLIGHT CHANCE POP THRU ABOUT 05Z OR 06Z PER THE
LATEST 13 KM RUC MODEL. NO OTHER CHANGES TO FORECAST AT THIS TIME.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
TEMPERATURES WILL BE ABLE TO RECOVER SOMEWHAT ON MONDAY IN THE
DOWNSLOPING FLOW AHEAD OF MAIN DEEP TROF SET TO CROSS THE REGION
MON NIGHT. CAA SURGE ARRIVES BY MID AFTN AFTER HIGHS REACH INTO
THE UPPER 40S TO NEAR 50 UNDER MAINLY SUNNY SKIES. THE DIURNAL
RISE OVER OBX WILL BE MINIMAL ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM SUN...A REINFORCING COLD FRONT AND SHARP UPPER TROUGH
MOVE ACROSS THE REGION MON NIGHT USHERING IN THE COLDEST AIR OF THE
SEASON WITH BLUSTERY NWLY WINDS THROUGH TUE. WILL SEE INCREASING MID
LAYER CLOUDS MON NIGHT/EARLY TUE ASSOC WITH THE UPPER TROUGH AND
WHILE SOME MODELS SHOWING SOME SATURATION IN THE -10C TO -20C LAYER
NOT ALL DO AND THE SUB CLOUD LAYER REMAINS VERY DRY SO DON`T BELIEVE
ANY PCPN WILL FALL ACROSS ERN NC EXCEPT OF THE COAST. WILL CONTINUE
TO MONITOR BUT HAVE KEPT POPS BELOW 10 PERCENT FOR NOW EXCEPT
OFFSHORE WATERS. IF ANY PCPN DOES FALL IT WILL LIKELY BE BETWEEN
MIDNIGHT AND NOON TUE AND IN THE FORM OF A BRIEF SNOW SHOWER OR
FLURRY THAT WILL BE LIGHT WITH NO ACCUMULATION EXPECTED. BLUSTERLY
NWLY WINDS WILL GUST AROUND 25-35 MPH TUE WITH WIND CHILL VALUES IN
THE 10S AND 20S. H85 TEMPS BOTTOM OUT AROUND -13C TO -15C TUE WITH
LOW LEVEL THICKNESSES AROUND 1270M KEEPING HIGHS IN THE U30S TO
AROUND 40.
HIGH PRES BUILDS ACROSS THE REGION TUE NIGHT AND WED ALLOWING WINDS
TO DIMINISH AND WITH GOOD RADIATIONAL COOLING TUE NIGHT WILL BE THE
COLDEST NIGHT OF THE SEASON WITH LOWS IN THE TEENS INLAND TO L/M20S
ALONG THE COAST. WILL SEE A SLOW WARMING TREND OF ABOUT 5 DEGREES
EACH DAY THE REST OF THE WEEK DESPITE SEVERAL WEAK FRONTS/TROUGH AND
MID LEVEL SHORTWAVES MOVING ACROSS THE REGION. THE AIRMASS WILL
REMAIN VERY DRY WITH NO PCPN EXPECTED THROUGH SAT. WHILE THERE ARE
SOME DIFFERENCES AMONG THE MODELS IT LOOKS LIKE THE NEXT
OPPORTUNITY FOR RAIN WILL COME SUNDAY AS SOUTHERN STREAM MOISTURE
MERGES WITH A NORTHERN STREAM TROUGH DIGGING ACROSS THE MID WEST.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH MONDAY/...
AS OF 630 PM SUNDAY...SOME BROKEN 4000-5000 FOOT CEILINGS WILL BE
LIKELY THRU 05Z OR 06Z AHEAD OF COLD FRONT WITH A FEW LIGHT
SHOWERS OR SPRINKLES POSSIBLE. COLD FRONT WILL THEN CLEAR THE AREA
WITH GUSTY NW WINDS AND MOSTLY CLEAR SKIES. VFR CONDITIONS SHOULD
PREVAIL THRU THE TAF PERIOD.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 300 PM SUN...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. A
STRONG FRONT CROSSES THE AREA MON NIGHT BRINGING BLUSTERY NW WINDS
GUSTING TO AROUND 30 KT THROUGH THE DAY TUE. LIGHTER WINDS EXPECTED
THE REST OF THE PERIOD WITH GUSTS MAINLY BLO 20 KT EACH AFTERNOON.
&&
.MARINE...
SHORT TERM /THROUGH MONDAY/...
AS OF 630 PM SUNDAY...SOUTHWEST WINDS ARE STARTING TO INCREASE AS
COLD FRONT WORKS ITS WAY INTO WESTERN PIEDMONT. MOST BUOY SITES
ARE UP TO THE 15 TO 20 KNOT RANGE...HOWEVER SEAS ARE STILL ONLY 2
TO 4 FEET. SEAS SHOULD GRADUALLY BUILD TO 4 TO 6 FEET LATER
TONIGHT AS WINDS RAMP UP BEHIND THE FRONT AFTER ABOUT 06Z. NO
SIGNIFICANT CHANGES TO THE CURRENT FORECAST AT THIS TIME.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 300 PM SUN...A REINFORCING COLD FRONT PUSHES ACROSS THE
WATERS MON NIGHT BRINGING ANOTHER W/NWLY SURGE. WINDS WILL
INCREASE TO AROUND 20-30 KT LATE MON EVENING AND OVERNIGHT PEAKING
AROUND 12Z TUE. SOME MODELS APPROACHING 30-35 KT AROUND 09-15Z AND
MAY NEED A GALE WATCH...ESPECIALLY FOR GUSTS...FOR THIS TIME FRAM
BUT WILL LET THE ONCOMING EVALUATE THE LATEST MODELS. USED A BLEND
OF SWAN AND WAVEWATCH THROUGH THE PERIOD WITH SEAS PEAKING AROUND
6-9 FT TUE AFTERNOON...WITH OFFSHORE FLOW BRINGING HIGHEST SEAS
ACROSS THE OUTER WATERS. WINDS AND SEAS DIMINISH TUE NIGHT AS HIGH
PRES BUILDS INTO THE AREA AND EXPECT SEAS TO DROP BELOW 6 FT BY
12Z WED.
SEVERAL WEAK SHORTWAVE TROUGH CROSS THE WATERS THROUGH THE LATTER
HALF OF THE WEEK BUT MODELS KEEPING ASSOC SURGES AOB 20 KT AND SEAS
AOB 5 FT...SO NOT ANTICIPATING ADDITIONAL SCA`S AFTER WED MORNING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST MONDAY FOR AMZ130-135.
SMALL CRAFT ADVISORY UNTIL 1 PM EST MONDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY UNTIL 11 AM EST MONDAY FOR AMZ156-158.
SMALL CRAFT ADVISORY UNTIL 3 PM EST MONDAY FOR AMZ150.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...SK
AVIATION...CTC/BTC/SK
MARINE...CTC/BTC/SK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1000 AM CST SAT DEC 31 2011
.DISCUSSION...
PRECIP BAND CURRENTLY EXTENDING FROM NORTHERN RED VALLEY INTO THE
SOUTHERN SHEYENNE VALLEY. PRECIP TYPE IS ALL OVER THE PLACE...WITH
REPORTS COMING IN OF A MIX OF MAINLY FZRA AND SN WITH A FEW IP
THROWN IN. THE MODELS...BOTH THE HRRR AND 12Z NAM...HAVE THE
PRECIP FURTHER WEST THAN RADAR SHOWS. CUT POPS QUITE A BIT IN THE
DEVILS LAKE BASIN AND WILL DROP THE ADVISORY IN THAT AREA. DO NOT
THINK WE WILL GET MUCH SNOW ACCUMULATION IN THE REST OF THE
ADVISORY AREA...BUT WILL CONTINUE THE HEADLINE UNTIL IT EXPIRES AT
NOON TO ALERT PEOPLE TO FZRA/SN CHANCES. AFTER NOON...PRECIP
BAND SHOULD WEAKEN AND MOVE FURTHER EAST. A FURTHER DUSTING OF
SNOW IS POSSIBLE MAINLY IN MN...WITH SOME RAIN MIXING IN OVER THE
SOUTHERN COUNTIES WHICH ARE HOVERING NEAR THE FREEZING MARK AT
THIS TIME AND COULD BE A FEW DEGREES WARMER BY AFTERNOON. WILL
CONTINUE TO KEEP HIGHS WHAT WE HAVE GOING FOR TODAY...AS THERE
SEEMS TO BE SOME DECENT WARMING ALONG THE PRE-FRONTAL TROUGH IN
WESTERN ND. THE TRUE COLD AIR SEEMS LIKE IT WILL HOLD OFF UNTIL
TONIGHT.
&&
.AVIATION...
CEILINGS ARE RANGING FROM LIFR TO VFR ACROSS THE AREA THIS
MORNING. VIS IN SNOW BANDS HAS GONE DOWN BELOW A MILE AT
TIMES...BUT THE PRECIP WILL MOVE OUT QUICKLY AND VIS SHOULD
RECOVER. THE PRECIP WILL MOVE EASTWARD INTO KTVF AND KBJI THIS
AFTERNOON...WHILE KDVL WILL CONTINUE TO BE VFR UNTIL NORTHWESTERLY
WINDS PICK UP TONIGHT. THE WINDS WILL BRING SOME REDUCTION TO VIS
DUE TO BLSN OVERNIGHT MAINLY AT KDVL AND KGFK.
&&
.PREV DISCUSSION... /ISSUED 254 AM CST SAT DEC 31 2011/
DISCUSSION...FORECAST CHALLENGE WILL BE PCPN
AMOUNTS/PHASE...TEMPERATURES AND WIND/BLSN POTENTIAL TONIGHT INTO
SUNDAY AND RELATED HEADLINES TO ALL. MODELS FAIRLY CLOSE AND WILL
USE BLEND.
CHALLENGING FORECAST IN THE SHORT TERM TO SAY THE LEAST. BROAD LOW
PRESSURE OVER THE NORTHERN HIGH PLAINS WILL ORGANIZE WITH SURFACE
LOWS TRACKING ACROSS SOUTHERN CANADIAN PRAIRIE PROVINCES AND ACROSS
SD TODAY. THERMAL PROFILES CURRENTLY VERY WARM WHERE PCPN IS
OCCURRING TO OUR WEST. COLUMN BEGINS TO COOL AS PCPN MOVES FIRST
INTO DVL BASIN AND THEN EASTWARD DURING THE DAY. JUST HOW FAST
COLUMN COOLS TO SWITCH TO SNOW BIG QUESTION AND UNSURE AT THIS
POINT. MODEL SOUNDINGS INDICATING POTENTIAL FOR MIXED BAG OF PCPN
PHASES. COULD INITIALLY SEE SOME ZR-/FZDZ WITH GFS SHOWING GOOD
SNOW PROFILE BY 18Z ACROSS NORTH HALF. HOW FAR TEMPERATURES WARM
WITH PREFRONTAL TROUGH PASSAGE ALSO A CHALLENGE AND COULD AFFECT
DEGREE OF ZR POTENTIAL. UPSTREAM TEMPERATURES ALONG BOUNDARY IN THE
MID- UPPER 30S AND COULD SEE ABOVE FREEZING TEMPERATURES HERE. FOR
THE MORNING WILL MAINTAIN ZR/S...S ACROSS NORTH THIS AFTERNOON
WITH -RASN ACROSS SOUTH WHERE LESS SNOW COVER AND WARMER START
SHOULD ALLOW FOR BETTER CHANCES TO GET ABOVE FREEZING. BASED ON
CURRENT PCPN LOCATION AND MODEL TRENDS WILL NEED TO BACK HIGHER
POPS FARTHER WEST DURING THE DAY. OVERALL EXPECTING GENERAL 1 TO 3
INCHES OF SNOW POSSIBLY A LITTLE MORE OVER THE FAR NE. AT THIS
POINT WILL BE HOLDING OFF ON WINTER WX/FREEZING RAIN ADVISORY AND
MONITOR OBSERVATIONS THROUGH THE EARLY MORNING.
CHALLENGE TONIGHT WILL BE BLSN/BLIZZARD POTENTIAL. FAIRLY LOW
CONFIDENCE AT THIS POINT ON TRUE BLIZZARD CONDITIONS FOR SEVERAL
REASONS. FOR THE MOST PART PCPN SHOULD BE DONE WHEN STRONGER WINDS
ARRIVE THIS EVENING. SNOW COVER FRESH BUT NOT PARTICULARLY DEEP.
HOW MUCH IF ANY FREEZING RAIN OCCURS AND HOW LONG TEMPERATURES GET
ABOVE FREEZING WILL DETERMINE CRUSTING OF WHAT SNOW THERE IS.
STRONG WINDS ALOFT...40 TO 50KTS HOWEVER THERE WILL BE AN
INVERSION OF SOME DEGREE TO OVERCOME. BEST PUSH OF LOW LEVEL COLD
ADVECTION WILL BE AHEAD OF STRONGER WINDS WITH MODELS INDICATING
WARM ADVECTION TOWARDS 06Z. WITH WINDS OCCURRING AT NIGHT AND ABOVE
THINKING NOT SURE IF STRONGER WINDS WILL BE ABLE TO PUNCH DOWN TO
THE SURFACE. DVL BASIN LIKELY TO SEE BEST CHANCES FOR STRONGEST
WINDS WITH HIGHER ELEVATION AND MORE SNOW. FARTHER EAST INTO THE
VALLEY W-NW WIND DIRECTION AND POTENTIAL INVERSION WILL MAKE IT
TOUGHER FOR STRONGER WINDS TO WORK DOWN. SOUTHERN HALF OF VALLEY
HAS VERY LITTLE SNOW SO BLSN WILL BE LIKELY CONFINED TO PATCHY
RESTRICTED VSBY IN OPEN AREAS. WITH IT BEING A HOLIDAY WEEKEND
WILL ISSUE BLIZZARD WATCH FOR DVL BASIN AND LATER SHIFTS CAN
ADJUST BASED ON WHAT OCCURS TODAY.
WINDY CONDITIONS WILL CONTINUE THROUGH NEW YEARS DAY. ANY -SHSN
LOOKS TO BE CONFINED TO AREAS MAINLY EAST OF THE VALLEY. WILL
LIKELY SEE CONTINUED BLSN IN OPEN AREAS ACROSS DVL BASIN INTO
NORTHERN VALLEY AND ADJACENT NW MN. COLD ADVECTION AND NOW SNOW WILL
LIMIT TEMPERATURE RECOVER. FAR SOUTH WITH LESS SNOW WILL HAVE BEST
CHANCE FOR RECOVERY.
THINGS QUIET DOWN SUNDAY NIGHT INTO EARLY NEXT WEEK AS HIGH
PRESSURE BUILDS IN. WITH SOME SNOW MOST AREAS AND THERMAL PROFILE
LOOK FOR MORE WINTER TIME TEMPERATURE TRENDS.
LONG TERM (TUESDAY-FRIDAY)...GFS/ECMWF IN DECENT AGREEMENT WITH
PATTERN. WEAK SYSTEM WILL CLIP THE NORTHERN FA ON TUESDAY...THEN
UPPER RIDGE BUILDS ACROSS THE WESTERN CONUS AND STORM TRACK ONCE
AGAIN SHOULD BE NORTH OF THE INTERNATIONAL BORDER. TEMPERATURES
SHOULD BE WELL ABOVE NORMAL...WITH SNOW AND CLOUD COVER DETERMINING
ACTUAL VALUES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NDZ008-016-
026>030-038-039-049-052.
BLIZZARD WATCH FROM 6 PM CST THIS EVENING THROUGH SUNDAY MORNING
FOR NDZ006-007-014-015-024-026-054.
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ001>005-007-
008.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
447 AM EST MON JAN 2 2012
.SYNOPSIS...
STRONG UPPER LEVEL LOW AND ARCTIC AIRMASS RESULTS IN WIND BLOWN SNOW
SHOWERS THROUGH TUESDAY. WEAKER COLD FRONT MOVES THROUGH WEDNESDAY.
DRY WITH MODERATING TEMPERATURES FOR THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
IR SATELLITE IMAGERY SHOWING MID AND LOW LEVEL CLOUD DECK
APPROACHING WESTERN FLANKS. A RIDGE OF LOW H85 MOISTURE WAS EVIDENT
AHEAD OF THIS CLOUD DECK...WHICH LED TO CLEARING OVER CENTRAL
PORTIONS OF CWA. THIS SHOULD FILL IN QUICKLY OVER NEXT SEVERAL HOURS.
RUC H85 MOISTURE ACCURATELY DEPICTING MOISTURE ASSOCIATED WITH LOW
AND MID LEVEL CLOUDS STREAMING DOWNSTREAM OF THE GREAT LAKES. CURRENT H85
TEMPS FROM RUC ARE ABOUT -9C. WITH RUC H925 TEMPS ABOUT -3C...LAPSE
RATES ARE STEEPENING AND SHOULD CONTINUE WITH ADDITIONAL CAA. STEEP
LAPSE RATES AND ADDED DEEP MOISTURE WILL ONLY ADD TO THE SPATIAL
COVERAGE OF SNOW SHOWERS ALREADY DEVELOPING NW INTO CENTRAL OHIO.
KEPT SNOW TOTALS CLOSE TO PREVIOUS FORECAST...BUT DID TWEAK EKN
VICINITY UP A BIT AS THAT AREA RECEIVED A QUICK 1.5 INCHES OF NEW
SNOW BEFORE MIDNIGHT...THIS SNOW COMING BEFORE THE REAL MOISTURE
ARRIVES. PLAN TO KEEP ADVISORIES THE SAME AS PREVIOUS FORECAST.
BELIEVE OUR NW WV COUNTIES COULD COME CLOSE TO MEETING ADVISORY
CRITERIA FOR SNOW TOTALS IN 12HR TIME FRAME...BUT WOULD LIKE TO SEE
TRENDS IN INITIAL SNOW DEVELOPMENT FIRST.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
COLD AIR ADVECTION CONTINUES INTO TUESDAY AFTERNOON. MODELS SHOWING
LAKE PLUMES ALSO EFFECTING THE AREA...ALTHOUGH DEEPER MOISTURE PULLS
OUT IN THE MORNING. SHOULD BE PLENTY OF SNOW FLAKES AROUND...BUT
ACCUMULATIONS SHOULD BE LIMITED...WITH THE BEST ACCUMULATIONS IN THE
LAKE PLUMES. WARM AIR ADVECTION THEN SETS IN FOR TUESDAY NIGHT...AND
SHOULD BRING AN END TO THE SNOW.
ANOTHER MUCH WEAKER SYSTEM SKIRTS NORTHERN PORTIONS OF THE REGION ON
WEDNESDAY AND WEDNESDAY NIGHT. COULD SEE SOME LIGHT SNOW IN THE
NORTHERN COUNTIES...BUT THIS SYSTEM IS FAIRLY MOISTURE STARVED...SO
WILL KEEP POPS LOW.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
ONE LAST UPPER LEVEL S/W TROF MOVES SE THROUGH THE AREA IN THE
LARGER SCALE NW FLOW ALOFT RIGHT AT THE START OF THE PERIOD.
UPSLOPE FLOW IN ITS WAKE SHOULD BRING LIGHT SNOW SHOWERS OR
FLURRIES TO THE MOUNTAINS WED NT INTO THU MORNING. WITH HEIGHTS
QUICKLY LIFTING THU...EXPECT THE AIR MASS IN THE WAKE OF THE FRONT
TO NOT BE QUITE AS COLD AS ITS PREDECESSOR...AND THE UPSLOPE EVENT
NO WHERE NEAR THE DURATION OR MAGNITUDE OF ITS PREDECESSOR.
HIGH PRESSURE CROSSES THU NT...FOLLOWED BY SW FLOW ON ITS BACK SIDE
FRI INTO THE WEEKEND. NEXT NORTHERN STREAM UPPER LEVEL S/W TROUGH
DRIVES SURFACE COLD FRONT THROUGH THE AREA OVER THE WEEKEND...WITH
MODEL DIFFERENCES ON TIMING. MOISTURE GETS DRAWN UP AHEAD OF THE
FRONT INTO THE FORECAST AREA JUST AS THE FRONT APPROACHES SAT
MORNING. AIR MASS BEHIND FRONT DOES NOT IT LEAST INITIALLY APPEAR
TO BE AS COLD AS THE ONE CHARGING THROUGH EARLY THIS WEEK.
UPPER LOW FORMS OVER THE SWRN CONUS EARLY IN THE WEEKEND IN RESPONSE
TO RIDGING OFF THE W COAST. MODELS THEN START TO EJECT THIS LOW
NEWD LATE IN THE WEEKEND WITH SOME TIMING DIFFERENCES IN TANDEM WITH
SIMILAR DIFFERENCES IN THE NORTHERN STREAM.
BLENDED IN MEX / HPC FOR TEMPERATURES...NO SIGNIFICANT CHANGES.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
LOW LEVEL MOISTURE PLUME EVIDENT ON WATER VAPOR IMAGERY STARTING
MOVE INTO OUR AREA. HAVE CIGS DROPPING TO MVFR W TO E OVER NEXT FEW
HOURS WITH ARRIVAL OF THIS MOISTURE. WILL KEEP MVFR CIGS OVER
LOWLAND COUNTIES THROUGH TODAY...HOWEVER VSBYS WILL DROP TO IFR OR
LOWER IN SHSN TODAY AND TONIGHT. EXPECT VSBYS TO BOUNCE UP AND
DOWN TODAY...THUS WILL INCLUDE TEMPO GROUPS TO COVER THIS. IN THE
MOUNTAINS OF WV EXPECTING CIGS AND VSBYS TO BE IFR AND BOUNCING IN
AND OUT OF LIFR IN INDIVIDUAL SHSN. IFR TO LIFR COULD PERSIST IN
THE MOUNTAINS FOR QUITE SOME TIME...EVEN BEYOND THE SCOPE OF THIS
ISSUANCE.
EXPECTING A SLOW DECREASE IN THE WIND GUSTS WHICH ARE ALREADY
EVIDENT IN THE OBSERVATIONS. SUSTAINED WINDS ARE NOT EXPECTED TO
DROP BELOW 12KTS TO 15KTS THROUGH 00Z TUESDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE:HIGH.
ALTERNATE SCENARIOS: CIGS OVER THE LOWLANDS MAY DROP TO IFR WITH
LOW LEVEL MOISTURE THROUGH TODAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 01/02/12
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
CRW CONSISTENCY M M M L L L L M L L L L
HTS CONSISTENCY M M H M L L L L M M M M
BKW CONSISTENCY L L M M M L M M L L L L
EKN CONSISTENCY L L M M M L L L L L L L
PKB CONSISTENCY L L M M M M M M L L L L
CKB CONSISTENCY L L M M M M M M L L L L
AFTER 12Z TUESDAY...
IFR IN SNOW SHOWERS POSSIBLE TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO NOON EST
TUESDAY FOR WVZ015-016-018-024>031-033-034.
WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR WVZ032-
035>040-046-047.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO NOON EST
TUESDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/TAX
NEAR TERM...TAX
SHORT TERM...RPY
LONG TERM...TRM
AVIATION...TAX
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
330 AM EST MON JAN 2 2012
.SYNOPSIS...
STRONG UPPER LEVEL LOW AND ARCTIC AIRMASS RESULTS IN WIND BLOWN SNOW
SHOWERS THROUGH TUESDAY. WEAKER COLD FRONT MOVES THROUGH WEDNESDAY.
DRY WITH MODERATING TEMPERATURES FOR THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1230AM UPDATE...
BUMPED UP POPS TO REPRESENT CURRENT RADAR TRENDS...ESPECIALLY IN
SE OHIO WHERE LATEST RUC ALREADY SHOWING H85 MOISTURE ADVECTING
IN. OTHERWISE...KEEPING PREVIOUS FORECAST ON TRACK.
930PM UPDATE...
ADJUSTED THE SNOWFALL AMOUNTS DOWN IN NORTHWEST WEST VIRGINIA AND
SOUTHEAST OHIO BY AN INCH OR SO IN TERMS OF STORM TOTAL.
TEMPERATURES WERE GIVEN SOME TLC...BUT WERE LINING UP FAIRLY WELL
AGAIN FOR THIS ISSUANCE. DESPITE READINGS NEAR 40F...ICE PELLETS
AND SNOW HAD BEEN REPORTED FROM A FEW DIFFERENT SOURCES...AND CKB
HAS -SN IN THE LATEST OB AT 36F. WILL EXPECT RADAR COVERAGE OF THE
PRECIPITATION TO INCREASE IN THE COMING HOURS WITH THE MAIN TROUGH
AXIS DIGGING INTO THE OHIO VALLEY.
PREVIOUS DISCUSSION...
THE UPPER SYSTEM WILL MOVE ACROSS THE MONDAY AFTERNOON. ABUNDANT
LOW-LEVEL MOISTURE SHOULD COMBINE WITH FORCING ASSOCIATED WITH
UPPER SYSTEM TO RESULT IN MEASURABLE SNOW ACROSS MOST OF THE
REGION.
UPSLOPE FLOW...ABUNDANT DEEP MOISTURE AND FAVORABLE TEMP PROFILE
WILL COMBINE TO RESULT IN ENHANCED SNOWFALL IN THE FAVORED UPSLOPE
REGION.
PLAN TO LEAVE ADVISORIES UNCHANGED AS FORECASTED SNOW AMOUNTS SHOULD
NOT REACH WARNING CRITERIA IN THE MOUNTAINS. PORTIONS OF NORTHERN
WV AND SOUTHEAST OH...NEAR PKB...COULD SEE SNOWFALL AMOUNTS
APPROACHING ADVISORY CRITERIA. AFTER COLLABORATING WITH NORTHERN
NEIGHBORS...NO PLANS TO ADD THAT REGION TO THE ADVISORY AT THIS
TIME.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
COLD AIR ADVECTION CONTINUES INTO TUESDAY AFTERNOON. MODELS SHOWING
LAKE PLUMES ALSO EFFECTING THE AREA...ALTHOUGH DEEPER MOISTURE PULLS
OUT IN THE MORNING. SHOULD BE PLENTY OF SNOW FLAKES AROUND...BUT
ACCUMULATIONS SHOULD BE LIMITED...WITH THE BEST ACCUMULATIONS IN THE
LAKE PLUMES. WARM AIR ADVECTION THEN SETS IN FOR TUESDAY NIGHT...AND
SHOULD BRING AN END TO THE SNOW.
ANOTHER MUCH WEAKER SYSTEM SKIRTS NORTHERN PORTIONS OF THE REGION ON
WEDNESDAY AND WEDNESDAY NIGHT. COULD SEE SOME LIGHT SNOW IN THE
NORTHERN COUNTIES...BUT THIS SYSTEM IS FAIRLY MOISTURE STARVED...SO
WILL KEEP POPS LOW.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
ONE LAST UPPER LEVEL S/W TROF MOVES SE THROUGH THE AREA IN THE
LARGER SCALE NW FLOW ALOFT RIGHT AT THE START OF THE PERIOD.
UPSLOPE FLOW IN ITS WAKE SHOULD BRING LIGHT SNOW SHOWERS OR
FLURRIES TO THE MOUNTAINS WED NT INTO THU MORNING. WITH HEIGHTS
QUICKLY LIFTING THU...EXPECT THE AIR MASS IN THE WAKE OF THE FRONT
TO NOT BE QUITE AS COLD AS ITS PREDECESSOR...AND THE UPSLOPE EVENT
NO WHERE NEAR THE DURATION OR MAGNITUDE OF ITS PREDECESSOR.
HIGH PRESSURE CROSSES THU NT...FOLLOWED BY SW FLOW ON ITS BACK SIDE
FRI INTO THE WEEKEND. NEXT NORTHERN STREAM UPPER LEVEL S/W TROUGH
DRIVES SURFACE COLD FRONT THROUGH THE AREA OVER THE WEEKEND...WITH
MODEL DIFFERENCES ON TIMING. MOISTURE GETS DRAWN UP AHEAD OF THE
FRONT INTO THE FORECAST AREA JUST AS THE FRONT APPROACHES SAT
MORNING. AIR MASS BEHIND FRONT DOES NOT IT LEAST INITIALLY APPEAR
TO BE AS COLD AS THE ONE CHARGING THROUGH EARLY THIS WEEK.
UPPER LOW FORMS OVER THE SWRN CONUS EARLY IN THE WEEKEND IN RESPONSE
TO RIDGING OFF THE W COAST. MODELS THEN START TO EJECT THIS LOW
NEWD LATE IN THE WEEKEND WITH SOME TIMING DIFFERENCES IN TANDEM WITH
SIMILAR DIFFERENCES IN THE NORTHERN STREAM.
BLENDED IN MEX / HPC FOR TEMPERATURES...NO SIGNIFICANT CHANGES.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
LOW LEVEL MOISTURE PLUME EVIDENT ON WATER VAPOR IMAGERY STARTING
TO APPROACH CWA. HAVE CIGS DROPPING TO MVFR W TO E OVER NEXT FEW
HOURS WITH ARRIVAL OF THIS MOISTURE. WILL KEEP MVFR CIGS OVER
LOWLAND COUNTIES THROUGH TODAY...HOWEVER VSBYS WILL DROP TO IFR OR
LOWER IN SHSN TODAY AND TONIGHT. EXPECT VSBYS TO BOUNCE UP AND
DOWN TODAY...THUS WILL INCLUDE TEMPO GROUPS TO COVER THIS. IN THE
MOUNTAINS OF WV EXPECTING CIGS AND VSBYS TO BE IFR AND BOUNCING IN
AND OUT OF LIFR IN INDIVIDUAL SHSN. IFR TO LIFR COULD PERSIST IN
THE MOUNTAINS FOR QUITE SOME TIME...EVEN BEYOND THE SCOPE OF THIS
ISSUANCE.
EXPECTING A SLOW DECREASE IN THE WIND GUSTS WHICH ARE ALREADY
EVIDENT IN THE OBSERVATIONS. SUSTAINED WINDS ARE NOT EXPECTED TO
DROP BELOW 12KTS TO 15KTS THROUGH 00Z TUESDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE:HIGH.
ALTERNATE SCENARIOS: CIGS OVER THE LOWLANDS MAY DROP TO IFR WITH
LOW LEVEL MOISTURE THROUGH TODAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 01/02/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H M M M L L L L L M M
HTS CONSISTENCY H H M M M M L L L L M M
BKW CONSISTENCY M M M M H H M M M M L L
EKN CONSISTENCY L L L M M M M L L L L L
PKB CONSISTENCY M M M M L L L L L L M M
CKB CONSISTENCY M M L M M M M M M M M M
AFTER 06Z TUESDAY...
IFR IN SNOW SHOWERS POSSIBLE TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO NOON EST
TUESDAY FOR WVZ015-016-018-024>031-033-034.
WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR WVZ032-
035>040-046-047.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO NOON EST
TUESDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/TAX
NEAR TERM...TAX
SHORT TERM...RPY
LONG TERM...TRM
AVIATION...26/TAX
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1248 AM EST MON JAN 2 2012
.SYNOPSIS...
STRONG UPPER LEVEL LOW AND ARCTIC AIRMASS RESULTS IN WIND BLOWN
SNOW SHOWERS THIS MORNING THROUGH TUESDAY. WEAKER COLD FRONT
MOVES THROUGH WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
1230AM UPDATE...
BUMPED UP POPS TO REPRESENT CURRENT RADAR TRENDS...ESPECIALLY IN
SE OHIO WHERE LATEST RUC ALREADY SHOWING H85 MOISTURE ADVECTING
IN. OTHERWISE...KEEPING PREVIOUS FORECAST ON TRACK.
930PM UPDATE...
ADJUSTED THE SNOWFALL AMOUNTS DOWN IN NORTHWEST WEST VIRGINIA AND
SOUTHEAST OHIO BY AN INCH OR SO IN TERMS OF STORM TOTAL.
TEMPERATURES WERE GIVEN SOME TLC...BUT WERE LINING UP FAIRLY WELL
AGAIN FOR THIS ISSUANCE. DESPITE READINGS NEAR 40F...ICE PELLETS
AND SNOW HAD BEEN REPORTED FROM A FEW DIFFERENT SOURCES...AND CKB
HAS -SN IN THE LATEST OB AT 36F. WILL EXPECT RADAR COVERAGE OF THE
PRECIPITATION TO INCREASE IN THE COMING HOURS WITH THE MAIN TROUGH
AXIS DIGGING INTO THE OHIO VALLEY.
PREVIOUS DISCUSSION...
THE UPPER SYSTEM WILL MOVE ACROSS THE MONDAY AFTERNOON. ABUNDANT
LOW-LEVEL MOISTURE SHOULD COMBINE WITH FORCING ASSOCIATED WITH
UPPER SYSTEM TO RESULT IN MEASURABLE SNOW ACROSS MOST OF THE
REGION.
UPSLOPE FLOW...ABUNDANT DEEP MOISTURE AND FAVORABLE TEMP PROFILE
WILL COMBINE TO RESULT IN ENHANCED SNOWFALL IN THE FAVORED UPSLOPE
REGION.
PLAN TO LEAVE ADVISORIES UNCHANGED AS FORECASTED SNOW AMOUNTS SHOULD
NOT REACH WARNING CRITERIA IN THE MOUNTAINS. PORTIONS OF NORTHERN
WV AND SOUTHEAST OH...NEAR PKB...COULD SEE SNOWFALL AMOUNTS
APPROACHING ADVISORY CRITERIA. AFTER COLLABORATING WITH NORTHERN
NEIGHBORS...NO PLANS TO ADD THAT REGION TO THE ADVISORY AT THIS
TIME.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
NOT MUCH CHANGE PLANNED FROM CURRENT FORECAST. STILL ON TRACK TO
SEE UPSLOPE EVENT DURING THIS PERIOD. MODELS ARE NOW AGREEING ON
LOCATION OF UPPER TROUGH AND TIMING OF IT SLIDING EAST.
ALSO...-12C TO -18C RH IS ABOVE 90 PERCENT STARTING THIS PERIOD
AND CONTINUING INTO EARLY TUESDAY. THIS IS OPTIMAL CRYSTAL GROWTH
FOR SNOW. WITH WINDS IN THE LOW LEVELS OUT OF THE NORTHWEST...GOOD
SNOW GROWTH...DECENT UPPER WAVE AND UPSLOPE...WILL INCREASE SNOW
AMOUNT A BIT OVERNIGHT MONDAY.
BY TUESDAY...DRIER AIR STARTS TO WORK ACROSS THE AREA AND SNOW WILL
TAPER OFF. AS THE UPPER TROUGH MOVES EAST OF THE AREA...CONDITIONS
WILL IMPROVE. DRY WEATHER WILL RETURN TUESDAY AFTERNOON THROUGH
EARLY WEDNESDAY. THE NEXT CLIPPER SYSTEM WILL SWING SOUTHEAST FROM
THE GREAT LAKES ON WEDNESDAY. COULD SEE SOME LIGHT SNOW SHOWERS
TOWARD THE END OF THE PERIOD. FOR NOW...WILL LEAVE THE BULK OF
WEDNESDAY DRY.
H85 TEMPS WILL CONTINUE TO BE IN THE TEENS BELOW 0C MONDAY NIGHT
THROUGH TUESDAY NIGHT. THIS WILL KEEP DAYTIME HIGHS IN THE TEENS TO
AROUND 20F IN THE LOWLAND AND SINGLE DIGITS BELOW 0F IN THE
MOUNTAINS. IF ANY CLEARING OCCURS OVERNIGHT TUESDAY IN THE
MOUNTAINS...COLDER TEMPS WILL BE LIKELY THERE. WARM AIR ADVECTION
RETURNS OVERNIGHT TUESDAY INTO WEDNESDAY. TEMPERATURES ON WEDNESDAY
WILL RETURN TO THE 30S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ONE LAST UPPER LEVEL S/W TROF MOVES SE THROUGH THE AREA IN THE
LARGER SCALE NW FLOW ALOFT RIGHT AT THE START OF THE PERIOD.
UPSLOPE FLOW IN ITS WAKE SHOULD BRING LIGHT SNOW SHOWERS OR
FLURRIES TO THE MOUNTAINS WED NT INTO THU MORNING. WITH HEIGHTS
QUICKLY LIFTING THU...EXPECT THE AIR MASS IN THE WAKE OF THE FRONT
TO NOT BE QUITE AS COLD AS ITS PREDECESSOR...AND THE UPSLOPE EVENT
NO WHERE NEAR THE DURATION OR MAGNITUDE OF ITS PREDECESSOR.
HIGH PRESSURE CROSSES THU NT...FOLLOWED BY SW FLOW ON ITS BACK SIDE
FRI INTO THE WEEKEND. NEXT NORTHERN STREAM UPPER LEVEL S/W TROUGH
DRIVES SURFACE COLD FRONT THROUGH THE AREA OVER THE WEEKEND...WITH
MODEL DIFFERENCES ON TIMING. MOISTURE GETS DRAWN UP AHEAD OF THE
FRONT INTO THE FORECAST AREA JUST AS THE FRONT APPROACHES SAT
MORNING. AIR MASS BEHIND FRONT DOES NOT IT LEAST INITIALLY APPEAR
TO BE AS COLD AS THE ONE CHARGING THROUGH EARLY THIS WEEK.
UPPER LOW FORMS OVER THE SWRN CONUS EARLY IN THE WEEKEND IN RESPONSE
TO RIDGING OFF THE W COAST. MODELS THEN START TO EJECT THIS LOW
NEWD LATE IN THE WEEKEND WITH SOME TIMING DIFFERENCES IN TANDEM WITH
SIMILAR DIFFERENCES IN THE NORTHERN STREAM.
BLENDED IN MEX / HPC FOR TEMPERATURES...NO SIGNIFICANT CHANGES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
LOW LEVEL MOISTURE PLUME EVIDENT ON WATER VAPOR IMAGERY STARTING
TO APPROACH CWA. HAVE CIGS DROPPING TO MVFR W TO E OVER NEXT FEW
HOURS WITH ARRIVAL OF THIS MOISTURE. WILL KEEP MVFR CIGS OVER
LOWLAND COUNTIES THROUGH TODAY...HOWEVER VSBYS WILL DROP TO IFR OR
LOWER IN SHSN TODAY AND TONIGHT. EXPECT VSBYS TO BOUNCE UP AND
DOWN TODAY...THUS WILL INCLUDE TEMPO GROUPS TO COVER THIS. IN THE
MOUNTAINS OF WV EXPECTING CIGS AND VSBYS TO BE IFR AND BOUNCING IN
AND OUT OF LIFR IN INDIVIDUAL SHSN. IFR TO LIFR COULD PERSIST IN
THE MOUNTAINS FOR QUITE SOME TIME...EVEN BEYOND THE SCOPE OF THIS
ISSUANCE.
EXPECTING A SLOW DECREASE IN THE WIND GUSTS WHICH ARE ALREADY
EVIDENT IN THE OBSERVATIONS. SUSTAINED WINDS ARE NOT EXPECTED TO
DROP BELOW 12KTS TO 15KTS THROUGH 00Z TUESDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE:HIGH.
ALTERNATE SCENARIOS: CIGS OVER THE LOWLANDS MAY DROP TO IFR WITH
LOW LEVEL MOISTURE THROUGH TODAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 01/02/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H M M M L L L L L M M
HTS CONSISTENCY H H M M M M L L L L M M
BKW CONSISTENCY M M M M H H M M M M L L
EKN CONSISTENCY L L L M M M M L L L L L
PKB CONSISTENCY M M M M L L L L L L M M
CKB CONSISTENCY M M L M M M M M M M M M
AFTER 06Z TUESDAY...
IFR IN SNOW SHOWERS POSSIBLE TUESDAY...CONDITIONS GRADUALLY IMPROVE
INTO WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO NOON EST
TUESDAY FOR WVZ015-016-018-024>031-033-034.
WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR WVZ032-
035>040-046-047.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO NOON EST
TUESDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...JB/TRM/TAX
NEAR TERM...26/JSH/TAX
SHORT TERM...JB
LONG TERM...TRM
AVIATION...26/TAX
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
335 PM CST SAT DEC 31 2011
.DISCUSSION.../ISSUED AT 335 PM CST/
LATEST RUC...NAM AND HRRR CONTINUE TO BE IN FAIRLY CLOSE AGREEMENT
WITH PRECIPITATION DEVELOPING LATE THIS AFTERNOON AND EVENING...
ESPECIALLY ALONG AND EAST OF INTERSTATE 29 ALONG AXIS OF STRONG H85
FRONTOGENESIS...WITH VERY LITTLE PRECIPITATION TO THE WEST. CURRENT
RADAR STARTING TO SHOW PRECIPITATION DEVELOPING OVER SOUTHEAST SOUTH
DAKOTA AHEAD OF SHORT WAVE AND WOULD EXPECT PRECIPITATION TO BECOME
MORE WIDESPREAD. COLD FRONT ALREADY MOVING EAST OF I29 AND SHOULD
MOVE THROUGH NORTHWEST IOWA AND SOUTHWEST MINNESOTA BY 01Z. LOOKS
LIKE DYNAMIC COOLING OF THE LAYER SHOULD NOT BE A PROBLEM AND RAIN
SHOULD CHANGE OVER TO SNOW FAIRLY QUICKLY AS UPPER WAVE APPROACHES.
LIKE TO SEE A QUICK 2 TO 4 INCH SNOW OVER FAR EASTERN CWA WITH AN 1
TO 2 INCHES BETWEEN I29 AND THE HEAVIEST SNOW. ADD THE STRONG WINDS
WITH THE SNOW AND WILL SEE SOME PRETTY BACK CONDITIONS FROM 00Z TO
06Z AND WILL KEEP WARNING GOING ACROSS THE FAR EAST WITH WINTER
WEATHER ADVISORY CONTINUING JUST TO THE WEST. EVEN THROUGH SNOWFALL
WILL NOT REACH WINTER STORMS CRITERIA...THE COMBINATION OF WIND AND
SNOW...PLUS THE HOLIDAY EVE MAKES IT REASONABLE TO ISSUE SINCE THERE
WILL BE PLENTY PEOPLE TRAVELING. SNOW SHOULD QUICKLY END AFTER 05Z
OR 06Z AS SYSTEM PULLS AWAY. WILL ALSO KEEP THE WIND ADVISORIES
GOING THROUGH SUNDAY WITH WIND GUST TO 35 TO 45 MPH TONIGHT AS
SYSTEM GETS WOUND UP.
WITH THESE CONTINUED STRONG WINDS SUNDAY WILL COME SOME LOW CLOUDS
IN THE COOLER AIR...MAINLY TO THE NORTHEAST HALF OF THE FORECAST
AREA. WHILE A FEW FLURRIES ARE NOT OUT OF THE QUESTION...HAVE
ELECTED TO GO WITHOUT FOR NOW. UPPER SYSTEM WILL BE PULLING EAST
STEADILY AND THE LOW CLOUD DECK IS EXPECTED TO GET PRETTY THIN.
ANOTHER THOUGHT IS WILL THERE BE ANY LINGERING BLOWING SNOW IN THE
FAR EAST AND HAVE LEFT THAT OUT AS WELL WITH MARGINAL ACCUMULATIONS
AND AT LEAST 6 HOURS WITHOUT ANY FALLING SNOW BEFORE THE START OF
THE DAY.
CLEARING LOOKS STRONG FOR SUNDAY NIGHT. KEEPING WIND ADVISORY IS
MARGINAL BUT AS EVENING WINDS SHOW A VERY SMALL DECREASE ON MODELS
WILL KEEP AS IS FOR SOME MN AND IA COUNTIES THROUGH MIDNIGHT.
COLDER...BUT YES STILL A LITTLE ABOVE NORMAL...TEMPERATURES SUNDAY
WILL COOL MODESTLY SUNDAY NIGHT WITH THE SLOW WIND DECREASE. MONDAY
SHOULD THEN BE FAIRLY SUNNY WITH SOME INCREASING HIGH THIN CLOUDS
AND A TAD COOLER THAN SUNDAY ON HIGHS...BUT OF COURSE WITH MUCH
LIGHTER WINDS AS SURFACE RIDGE MOVES OVER AREA. WARMING STARTS
MONDAY NIGHT AND CONTINUES THROUGH PASSAGE OF WEAK TUESDAY SHORT
WAVE WHICH WILL BRING ONLY SOME ASSOCIATED CLOUD COVER AND NO
PRECIPITATION. WARMING WITH FAIRLY CLEAR SKIES WILL CONTINUE
WEDNESDAY AND PEAK THURSDAY WITH A POTENTIAL FOR RECORD HIGH
TEMPERATURES THURSDAY...AT LEAST HERE AT FSD WHERE WE HAVE OUR
CURRENTLY LATEST SUB 50 DAILY RECORD HIGH FOR THAT DATE. FRIDAY AND
SATURDAY LOOKS LIKE COOLING AND PROBABLY UNEVENTFUL...WITH LITTLE OR
NO PRECIPITATION AND WINDS BEHIND FRIDAY COLD FRONT FOR NOW
PROJECTED TO BE LESS THAN CURRENT SYSTEM. / WILLIAMS
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
RAIN AND SNOW SHOULD DEVELOP ALONG THE INTERSTATE 29 CORRIDOR THIS
AFTERNOON AND EXPAND ACROSS SOUTHWEST MINNESOTA AND NORTHWEST IOWA.
CEILINGS AND VISIBILITIES WILL BECOME MVFR EAST OF I29 AND
OCCASIONALLY LOWER TO IFR DUE TO SNOW. CEILINGS SHOULD BECOME VFR
AFTER 06Z WITH VFR CONDITIONS EXPECTED WEST OF I29 THROUGH 18Z
SUNDAY. STRONG NORTHWEST WINDS OF 25 TO 40 MPH...WITH GUSTS TO 50
MPH WILL SPREAD ACROSS THE REGION THIS AFTERNOON AND EVENING BEHIND
COLD FRONT AND PERSIST THROUGH 18Z SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR IAZ001-012-020-031.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT
CSTTONIGHT FOR IAZ002-013-021-032.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR IAZ002-013-021-032.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR IAZ003-014-022.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY
NIGHT FOR IAZ003-014-022.
MN...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR MNZ098.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT
CST TONIGHT FOR MNZ071-072-080-089.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR MNZ071-072-080-089-097.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR MNZ081-090.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY
NIGHT FOR MNZ081-090.
NE...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR NEZ013-014.
SD...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ038>040-052>056-
058>062-064>071.
WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ050-057-063.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1120 AM CST SAT DEC 31 2011
.DISCUSSION.../ISSUED AT 1120 AM CST/
LATEST RUC...NAM AND HRRR MORE IN AGREEMENT WITH PRECIPITATION
DEVELOPING DURING TEH AFTERNOON...ESPECIALLY ALONG AND EAST OF
INTERSTATE 29 ALONG AXIS OF STRONG H85 FRONTALGENESIS...WITH VERY
LITTLE PRECIPITATION TO THE WEST. CURRENT RADAR TRENDS SEEM TO
VALIDATE THIS SCENARIO AND WILL TRIM BACK POPS WEST OF JAMES VALLEY
AND INCREASE POPS ALONG I29 CORRIDOR FOR FSD-SUX WHERE POPS WERE
ONLY AROUND 70%. SHOULD START AS RAIN AND THEN SWITCH TO SNOW BY
LATE AFTERNOON AS LAYER COOLS DUE TO STRONG LIFT AND EVAPORATION.
COULD SEE A QUIKC INCH OF SNOW ALONG I29 WITH 2 TO 4 INCHES FURTHER
EAST. HAVE UPGRADED FSR EASTERN CWA TO WINTER STORMS WARNING FROM
00Z TO 06Z AND MAY NEED TO UPGRADE TO BLIZZARD WARNING WITH
AFTERNOON FORECAST BASED ON TRENDS.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
RAIN AND SNOW SHOULD DEVELOP ALONG THE INTERSTATE 29 CORRIDOR THIS
AFTERNOON AND EXPAND ACROSS SOUTHWEST MINNESOTA AND NORTHWEAST IOWA.
CEILINGS AND VISIBLITIES WILL BECOME MVFR EAST OF I29 AND
OCCASIONALLY LOWER TO IFR DUE TO SNOW. CEILINGS SHOULD BECOME VFR
AFTER 06Z WITH VFR CONDITIONS EXPECTED WEST OF I29 THROUGH 18Z
SUNDAY. STRONG NORTHWEST WINDS OF 25 TO 40 MPH...WITH GUSTS TO 50
MPH WILL SPREAD ACROSS THE REGION THIS AFTERNOON AND EVENING BEHIND
COLD FRONT AND PERSIST THROUGH 18Z SUNDAY.
&&
.PREVIOUS DISCUSSION.../ISSUED AT 400 AM CST/
MAIN FOCUS OF THIS PACKAGE IS THE POTENTIAL FOR SNOW AND WIND LATER
TODAY AND TONIGHT...ESPECIALLY ACROSS SOUTHWEST MINNESOTA AND INTO
NORTHWEST IOWA.
AT 09Z...LOWS PRESSURE WAS LOCATED OVER SOUTHEAST MONTANA. THE
STRENGTHENING GRADIENT HAS RESULTED IN INCREASING SOUTHEAST FLOW
ACROSS MUCH OF THE AREA WITH TEMPERATURES REMAINING NEAR FREEZING.
AS THE LOW RAPIDLY MOVES TO THE EAST...IT WILL DRAG A STRONG COLD
FRONT ACROSS THE DAKOTAS AND NEBRASKA THIS MORNING...AND SOUTHWEST
MINNESOTA AND NORTHWEST IOWA THIS AFTERNOON. BEHIND THE SURFACE
FRONT...WINDS WILL RAPIDLY INCREASE WITH SUSTAINED WINDS LIKELY TO
EXCEED 30 MPH BY LATE AFTERNOON...ESPECIALLY IN THE MISSOURI VALLEY.
WOULD NOT BE SURPRISED IF SOME AREAS IN THE MISSOURI VALLEY SEE
GUSTS TO 50 MPH LATE THIS AFTERNOON.
STRONG 700 MB FRONTOGENESIS WILL FOLLOW THE PASSAGE OF THE SURFACE
FRONT. ACCOMPANYING THIS AREA OF MID-LEVEL FRONTOGENESIS...A VERY
STRONG PV ANOMALY WILL MOVE ACROSS THE DAKOTAS. A LINE OF LIGHT
PRECIPITATION IS EXPECTED TO DEVELOP AS THE UPPER LEVEL ANOMALY
INTERACTS WITH THE 700 MB FRONT. FOR NOW...EXPECTING THAT THIS
PRECIPITATION WILL BEGIN AS RAIN IN THE JAMES AND MISSOURI VALLEYS
AS WET BULB TEMPERATURE REMAIN BARELY ABOVE FREEZING. HOWEVER...IF
COLDER AIR FOLLOWS MORE QUICKLY BEHIND THE SURFACE MAY SEE A MIX
WITH SNOW EVEN AS FAR WEST AS HURON AND MITCHELL. PRECIPITATION
AMOUNTS IN THE JAMES VALLEY ARE EXPECTED TO BE AROUND A TENTH OF AN
INCH. AS PV ANOMALY MOVES INTO WRN IOWA...IT WILL CYCLONICALLY
WRAP-UP. THIS WILL INTENSIFY THE 700 MB FRONT AS IT MOVES TOWARD
I-29 AND EXPECTATION IS THAT THE PRECIPITATION BAND WILL BECOME MORE
INTENSE AND ORGANIZED LATE THIS AFTERNOON AND THIS EVENING. IN
ADDITION...WITH HIGHER PRECIPITATION RATES AND COLDER AIR WORKING
IN...IT IS EXPECTED PRECIPITATION WILL BEGIN TO MIX WITH OR CHANGE
TO SNOW TOWARD I-29 AND ESPECIALLY INTO SW MN AND NW IA AFTER 00Z.
THERE IS EXPECTED TO BE AN AREA OF 1 TO 3 INCHES OF SNOW OVER MUCH
OF SW MN AND ALONG HIGHWAY 71 IN NORTHWEST IOWA INCLUDING SPENCER
AND STORM LAKE. WITH THE SNOWFALL...WILL BE SUSTAINED WINDS OVER 30
MPH WITH GUSTS APPROACHING 50 MPH. EVEN WITH NO SNOW CURRENTLY ON
THE GROUND...THE COMBINATION OF FALLING AND ACCUMULATING SNOW WILL
QUICKLY PRODUCE WIDESPREAD BLOWING SNOW...ESPECIALLY THIS
EVENING...WHICH WILL REDUCE VISIBILITIES BELOW A HALF MILE.
THEREFORE HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING
SNOW FROM 4 PM TO MIDNIGHT. EVEN WHERE NO ADVISORY IS IN
EFFECT...SUCH AS AROUND SIOUX FALLS...CHEROKEE...AND SHELDON...BRIEF
PERIODS OF LOW VISIBILITIES CAN BE EXPECTED WHEN SNOW IS FALLING
LATE THIS AFTERNOON AND EARLY THIS EVENING.
BECAUSE OF THE RAPID INTENSIFICATION OF THE UPPER LEVEL
WAVE...CONFIDENCE IN THE EXACT AREA OF SNOWFALL REMAINS UNCERTAIN.
THERE ARE TWO CONCERNS...FIRST PRECIPITATION SWITCHES MORE QUICKLY
TO SNOW SO THAT SOME AREAS SEE IN EXCESS OF 3 INCHES OF SNOW...WHICH
WOULD BE ENOUGH TO PRODUCE BLIZZARD CONDITIONS IN OPEN AREAS WITH
THE EXPECTED WINDS. SECOND...HEAVIER SNOWFALL OF 1 TO 3 INCHES COULD
EXTEND FARTHER WEST INCLUDING I-29 OR EVEN AS FAR WEST AS HIGHWAY 81
WHICH WOULD AFFECT YANKTON...BROOKINGS...SIOUX FALLS AND EVEN SIOUX
CITY. PERSONS PLANNING TRAVEL LATER THIS AFTERNOON AND TONIGHT
SHOULD MONITOR FORECASTS.
AFTER THE SNOW ENDS...COULD SEE BLOWING SNOW THE REMAINDER OF THE
NIGHT IN SW MN AND NW IA. OTHERWISE...WINDS OF 20 TO 40 MPH ARE
EXPECTED. THIS WILL KEEP THE ATMOSPHERE WELL MIXED SO LOWS WILL
REMAIN IN THE 20S. WINDY CONDITIONS WILL CONTINUE THROUGH SUNDAY
WITH LITTLE WARMING. MOST PLACES WILL SEE HIGHS FROM THE MID 20S TO
THE LOWER 30S. THE WINDS ARE EXPECTED TO REMAIN OVER 30 MPH IN SW
MN AND NW IA INTO SUNDAY SO EXTENDED THE WIND ADVISORY INTO SUNDAY.
WITH COLD AIR CONTINUING TO FILTER IN...LOWS WILL BE IN THE TEENS.
MONDAY WILL SEE A RIDGE MOVE OVER THE AREA. WITH LIMITED MIXING AND
SOME SNOW COVER EXPECTED IN OUR ERN CWA...HIGHS IN SW MN AND NW IOWA
WILL STAY IN THE MID 20S. FARTHER WEST...WARM AIR WILL BEGIN TO MOVE
IN AND TEMPERATURES WILL RISE INTO THE LOWER 30S. AS THE RIDGE MOVES
OVER THE AREA MONDAY NIGHT...EXPECT SOME RADIATION
COOLING...ESPECIALLY ALONG AND EAST OF I29 AND LOWER MINS TO AROUND
10 ABOVE. ALONG AND WEST OF THE JAMES RIVER...INCREASING SOUTH WINDS
WILL KEEP LOWS IN THE TEENS.
A WARMING TREND CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK WITH
NEAR RECORD TEMPERATURES POSSIBLE BY THURSDAY. NO PRECIPITATION IS
EXPECTED.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR IAZ001-012-020-031.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR IAZ002-013-021-032.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR IAZ002-013-021-032.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR IAZ003-014-022.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT
FOR IAZ003-014-022.
MN...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR MNZ098.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR MNZ071-072-080-089.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR MNZ071-072-080-089-097.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR MNZ081-090.
WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT
FOR MNZ081-090.
NE...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR NEZ013-014.
SD...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ038>040-052>056-
058>062-064>071.
WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ050-057-063.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
945 AM CST SAT DEC 31 2011
.DISCUSSION.../ISSUED AT 945 AM CST/
LATEST RUC...NAM AND HRRR MORE IN AGREEMENT WITH PRECIPITATION
DEVELOPING DURING TEH AFTERNOON...ESPECIALLY ALONG AND EAST OF
INTERSTATE 29 ALONG AXIS OF STRONG H85 FRONTALGENESIS...WITH VERY
LITTLE PRECIPITATION TO THE WEST. CURRENT RADAR TRENDS SEEM TO
VALIDATE THIS SCENARIO AND WILL TRIM BACK POPS WEST OF JAMES VALLEY
AND INCREASE POPS ALONG I29 CORRIDOR FOR FSD-SUX WHERE POPS WERE
ONLY AROUND 70%. SHOULD START AS RAIN AND THEN SWITCH TO SNOW BY
LATE AFTERNOON AS LAYER COOLS DUE TO STRONG LIFT AND EVAPORATION.
COULD SEE A QUIKC INCH OF SNOW ALONG I29 WITH 1 TO 3 INCHES FURTHER
EAST. WILL ADD ANOTHER ROW OF COUNTIES TO WINTER WEATHER ADVISORY
OVER NORTHWEST IOWA. FINALLY...EXPECT THE STRONG WILL TO SPREAD
ACROSS CWA THIS AFTERNOON INTO EARLY EVENING BEHIND COLD FRONT. FOR
NOW WILL NOT UPGRADE FAR WEST TO HIGH WIND WARNING...AS CRITERIA MAY
ONLY BE MET FOR AN HOUR OR TWO. SO WIND ADVISORY ACROSS THE CWA
LOOKS MORE REASONABLE.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
A BAND OF RAIN WILL DEVELOP AROUND 18Z NEAR THE JAMES RIVER
VALLEY...THEN PROGRESS EAST THROUGH THE AFTERNOON. THE RAIN SHOULD
CHANGE TO SNOW AROUND INTERSTATE 29 AFTER ABOUT 23Z WITH SOME
ACCUMULATIONS LIKELY ALONG AND EAST OF INTERSTATE 29. BECAUSE OF THE
VERY STRONG NORTHWEST WINDS THAT WILL DEVELOP THROUGH THE DAY SOME
REDUCTION OF VISIBILITY WILL BE LIKELY WITH BLOWING
SNOW...ESPECIALLY EAST OF INTERSTATE 29...POSSIBLY INTO THE IFR
CATEGORY AT TIMES. OTHERWISE...NORTHWEST WINDS WILL GUST TO AROUND
45 MPH IN MOST LOCATIONS FROM LATE THIS MORNING INTO THE
EVENING...DECREASING ONLY SLIGHTLY OVERNIGHT INTO SUNDAY MORNING.
CEILINGS SHOULD MAINLY STAY IN THE VFR CATEGORY ALTHOUGH SOME BRIEF
MVFR CEILINGS WILL BE POSSIBLE WITHIN THE RAIN AND SNOW BAND. /08
&&
.PREVIOUS DISCUSSION.../ISSUED AT 400 AM CST/
MAIN FOCUS OF THIS PACKAGE IS THE POTENTIAL FOR SNOW AND WIND LATER
TODAY AND TONIGHT...ESPECIALLY ACROSS SOUTHWEST MINNESOTA AND INTO
NORTHWEST IOWA.
AT 09Z...LOWS PRESSURE WAS LOCATED OVER SOUTHEAST MONTANA. THE
STRENGTHENING GRADIENT HAS RESULTED IN INCREASING SOUTHEAST FLOW
ACROSS MUCH OF THE AREA WITH TEMPERATURES REMAINING NEAR FREEZING.
AS THE LOW RAPIDLY MOVES TO THE EAST...IT WILL DRAG A STRONG COLD
FRONT ACROSS THE DAKOTAS AND NEBRASKA THIS MORNING...AND SOUTHWEST
MINNESOTA AND NORTHWEST IOWA THIS AFTERNOON. BEHIND THE SURFACE
FRONT...WINDS WILL RAPIDLY INCREASE WITH SUSTAINED WINDS LIKELY TO
EXCEED 30 MPH BY LATE AFTERNOON...ESPECIALLY IN THE MISSOURI VALLEY.
WOULD NOT BE SURPRISED IF SOME AREAS IN THE MISSOURI VALLEY SEE
GUSTS TO 50 MPH LATE THIS AFTERNOON.
STRONG 700 MB FRONTOGENESIS WILL FOLLOW THE PASSAGE OF THE SURFACE
FRONT. ACCOMPANYING THIS AREA OF MID-LEVEL FRONTOGENESIS...A VERY
STRONG PV ANOMALY WILL MOVE ACROSS THE DAKOTAS. A LINE OF LIGHT
PRECIPITATION IS EXPECTED TO DEVELOP AS THE UPPER LEVEL ANOMALY
INTERACTS WITH THE 700 MB FRONT. FOR NOW...EXPECTING THAT THIS
PRECIPITATION WILL BEGIN AS RAIN IN THE JAMES AND MISSOURI VALLEYS
AS WET BULB TEMPERATURE REMAIN BARELY ABOVE FREEZING. HOWEVER...IF
COLDER AIR FOLLOWS MORE QUICKLY BEHIND THE SURFACE MAY SEE A MIX
WITH SNOW EVEN AS FAR WEST AS HURON AND MITCHELL. PRECIPITATION
AMOUNTS IN THE JAMES VALLEY ARE EXPECTED TO BE AROUND A TENTH OF AN
INCH. AS PV ANOMALY MOVES INTO WRN IOWA...IT WILL CYCLONICALLY
WRAP-UP. THIS WILL INTENSIFY THE 700 MB FRONT AS IT MOVES TOWARD
I-29 AND EXPECTATION IS THAT THE PRECIPITATION BAND WILL BECOME MORE
INTENSE AND ORGANIZED LATE THIS AFTERNOON AND THIS EVENING. IN
ADDITION...WITH HIGHER PRECIPITATION RATES AND COLDER AIR WORKING
IN...IT IS EXPECTED PRECIPITATION WILL BEGIN TO MIX WITH OR CHANGE
TO SNOW TOWARD I-29 AND ESPECIALLY INTO SW MN AND NW IA AFTER 00Z.
THERE IS EXPECTED TO BE AN AREA OF 1 TO 3 INCHES OF SNOW OVER MUCH
OF SW MN AND ALONG HIGHWAY 71 IN NORTHWEST IOWA INCLUDING SPENCER
AND STORM LAKE. WITH THE SNOWFALL...WILL BE SUSTAINED WINDS OVER 30
MPH WITH GUSTS APPROACHING 50 MPH. EVEN WITH NO SNOW CURRENTLY ON
THE GROUND...THE COMBINATION OF FALLING AND ACCUMULATING SNOW WILL
QUICKLY PRODUCE WIDESPREAD BLOWING SNOW...ESPECIALLY THIS
EVENING...WHICH WILL REDUCE VISIBILITIES BELOW A HALF MILE.
THEREFORE HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING
SNOW FROM 4 PM TO MIDNIGHT. EVEN WHERE NO ADVISORY IS IN
EFFECT...SUCH AS AROUND SIOUX FALLS...CHEROKEE...AND SHELDON...BRIEF
PERIODS OF LOW VISIBILITIES CAN BE EXPECTED WHEN SNOW IS FALLING
LATE THIS AFTERNOON AND EARLY THIS EVENING.
BECAUSE OF THE RAPID INTENSIFICATION OF THE UPPER LEVEL
WAVE...CONFIDENCE IN THE EXACT AREA OF SNOWFALL REMAINS UNCERTAIN.
THERE ARE TWO CONCERNS...FIRST PRECIPITATION SWITCHES MORE QUICKLY
TO SNOW SO THAT SOME AREAS SEE IN EXCESS OF 3 INCHES OF SNOW...WHICH
WOULD BE ENOUGH TO PRODUCE BLIZZARD CONDITIONS IN OPEN AREAS WITH
THE EXPECTED WINDS. SECOND...HEAVIER SNOWFALL OF 1 TO 3 INCHES COULD
EXTEND FARTHER WEST INCLUDING I-29 OR EVEN AS FAR WEST AS HIGHWAY 81
WHICH WOULD AFFECT YANKTON...BROOKINGS...SIOUX FALLS AND EVEN SIOUX
CITY. PERSONS PLANNING TRAVEL LATER THIS AFTERNOON AND TONIGHT
SHOULD MONITOR FORECASTS.
AFTER THE SNOW ENDS...COULD SEE BLOWING SNOW THE REMAINDER OF THE
NIGHT IN SW MN AND NW IA. OTHERWISE...WINDS OF 20 TO 40 MPH ARE
EXPECTED. THIS WILL KEEP THE ATMOSPHERE WELL MIXED SO LOWS WILL
REMAIN IN THE 20S. WINDY CONDITIONS WILL CONTINUE THROUGH SUNDAY
WITH LITTLE WARMING. MOST PLACES WILL SEE HIGHS FROM THE MID 20S TO
THE LOWER 30S. THE WINDS ARE EXPECTED TO REMAIN OVER 30 MPH IN SW
MN AND NW IA INTO SUNDAY SO EXTENDED THE WIND ADVISORY INTO SUNDAY.
WITH COLD AIR CONTINUING TO FILTER IN...LOWS WILL BE IN THE TEENS.
MONDAY WILL SEE A RIDGE MOVE OVER THE AREA. WITH LIMITED MIXING AND
SOME SNOW COVER EXPECTED IN OUR ERN CWA...HIGHS IN SW MN AND NW IOWA
WILL STAY IN THE MID 20S. FARTHER WEST...WARM AIR WILL BEGIN TO MOVE
IN AND TEMPERATURES WILL RISE INTO THE LOWER 30S. AS THE RIDGE MOVES
OVER THE AREA MONDAY NIGHT...EXPECT SOME RADIATION
COOLING...ESPECIALLY ALONG AND EAST OF I29 AND LOWER MINS TO AROUND
10 ABOVE. ALONG AND WEST OF THE JAMES RIVER...INCREASING SOUTH WINDS
WILL KEEP LOWS IN THE TEENS.
A WARMING TREND CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK WITH
NEAR RECORD TEMPERATURES POSSIBLE BY THURSDAY. NO PRECIPITATION IS
EXPECTED.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR IAZ001-012-020-031.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR IAZ002-003-013-014-021-022-032.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR IAZ002-003-013-014-021-022-032.
MN...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR MNZ098.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR MNZ071-072-080-081-089-090.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR MNZ071-072-080-081-089-090-097.
NE...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR NEZ013-014.
SD...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ038>040-052>056-
058>062-064>071.
WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ050-057-063.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
405 AM CST SAT DEC 31 2011
.DISCUSSION.../ISSUED AT 400 AM CST/
MAIN FOCUS OF THIS PACKAGE IS THE POTENTIAL FOR SNOW AND WIND LATER
TODAY AND TONIGHT...ESPECIALLY ACROSS SOUTHWEST MINNESOTA AND INTO
NORTHWEST IOWA.
AT 09Z...LOWS PRESSURE WAS LOCATED OVER SOUTHEAST MONTANA. THE
STRENGTHENING GRADIENT HAS RESULTED IN INCREASING SOUTHEAST FLOW
ACROSS MUCH OF THE AREA WITH TEMPERATURES REMAINING NEAR FREEZING.
AS THE LOW RAPIDLY MOVES TO THE EAST...IT WILL DRAG A STRONG COLD
FRONT ACROSS THE DAKOTAS AND NEBRASKA THIS MORNING...AND SOUTHWEST
MINNESOTA AND NORTHWEST IOWA THIS AFTERNOON. BEHIND THE SURFACE
FRONT...WINDS WILL RAPIDLY INCREASE WITH SUSTAINED WINDS LIKELY TO
EXCEED 30 MPH BY LATE AFTERNOON...ESPECIALLY IN THE MISSOURI VALLEY.
WOULD NOT BE SURPRISED IF SOME AREAS IN THE MISSOURI VALLEY SEE
GUSTS TO 50 MPH LATE THIS AFTERNOON.
STRONG 700 MB FRONTOGENESIS WILL FOLLOW THE PASSAGE OF THE SURFACE
FRONT. ACCOMPANYING THIS AREA OF MID-LEVEL FRONTOGENESIS...A VERY
STRONG PV ANOMALY WILL MOVE ACROSS THE DAKOTAS. A LINE OF LIGHT
PRECIPITATION IS EXPECTED TO DEVELOP AS THE UPPER LEVEL ANOMALY
INTERACTS WITH THE 700 MB FRONT. FOR NOW...EXPECTING THAT THIS
PRECIPITATION WILL BEGIN AS RAIN IN THE JAMES AND MISSOURI VALLEYS
AS WET BULB TEMPERATURE REMAIN BARELY ABOVE FREEZING. HOWEVER...IF
COLDER AIR FOLLOWS MORE QUICKLY BEHIND THE SURFACE MAY SEE A MIX
WITH SNOW EVEN AS FAR WEST AS HURON AND MITCHELL. PRECIPITATION
AMOUNTS IN THE JAMES VALLEY ARE EXPECTED TO BE AROUND A TENTH OF AN
INCH. AS PV ANOMALY MOES INTO WRN IOWA...IT WILL CYCLONICALLY
WRAP-UP. THIS WILL INTENISIFY THE 700 MB FRONT AS IT MOVES TOWARD
I-29 AND EXPECTATION IS THAT THE PRECIPITATION BAND WILL BECOME MORE
INTENSE AND ORGANIZED LATE THIS AFTERNOON AND THIS EVENING. IN
ADDITION...WITH HIGHER PRECIPITATION RATES AND COLDER AIR WORKING
IN...IT IS EXPECTED PRECIPITATION WILL BEGIN TO MIX WITH OR CHANGE
TO SNOW TOWARD I-29 AND ESPECIALLY INTO SW MN AND NW IA AFTER 00Z.
THERE IS EXPECTED TO BE AN AREA OF 1 TO 3 INCHES OF SNOW OVER MUCH
OF SW MN AND ALONG HIGHWAY 71 IN NORTHWEST IOWA INCLUDING SPENCER
AND STORM LAKE. WITH THE SNOWFALL...WILL BE SUSTAINED WINDS OVER 30
MPH WITH GUSTS APPROACHING 50 MPH. EVEN WITH NO SNOW CURRENTLY ON
THE GROUND...THE COMBINATION OF FALLING AND ACCUMULATING SNOW WILL
QUICKLY PRODUCE WIDESPREAD BLOWING SNOW...ESPECIALLY THIS
EVENING...WHICH WILL REDUCE VISIBILITIES BELOW A HALF MILE.
THEREFORE HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING
SNOW FROM 4 PM TO MIDNIGHT. EVEN WHERE NO ADVISORY IS IN
EFFECT...SUCH AS AROUND SIOUX FALLS...CHEROKEE...AND SHELDON...BRIEF
PERIODS OF LOW VISIBILITIES CAN BE EXPECTED WHEN SNOW IS FALLING
LATE THIS AFTERNOON AND EARLY THIS EVENING.
BECAUSE OF THE RAPID INTENSIFICATION OF THE UPPER LEVEL
WAVE...CONFIDENCE IN THE EXACT AREA OF SNOWFALL REMAINS UNCERTAIN.
THERE ARE TWO CONCERNS...FIRST PRECIPTIATION SWITCHES MORE QUICKLY
TO SNOW SO THAT SOME AREAS SEE IN EXCESS OF 3 INCHES OF SNOW...WHICH
WOULD BE ENOUGH TO PRODUCE BLIZZARD CONDITIONS IN OPEN AREAS WITH
THE EXPECTED WINDS. SECOND...HEAVIER SNOWFALL OF 1 TO 3 INCHES COULD
EXTEND FARTHER WEST INCLUDING I-29 OR EVEN AS FAR WEST AS HIGHWAY 81
WHICH WOULD AFFECT YANKTON...BROOKINGS...SIOUX FALLS AND EVEN SIOUX
CITY. PERSONS PLANNING TRAVEL LATER THIS AFTERNOON AND TONIGHT
SHOULD MONITOR FORECASTS.
AFTER THE SNOW ENDS...COULD SEE BLOWING SNOW THE REMAINDER OF THE
NIGHT IN SW MN AND NW IA. OTHERWISE...WINDS OF 20 TO 40 MPH ARE
EXPECTED. THIS WILL KEEP THE ATMSOSPHERE WELL MIXED SO LOWS WILL
REMAIN IN THE 20S. WINDY CONDITIONS WILL CONTINUE THROUGH SUNDAY
WITH LITTLE WARMING. MOST PLACES WILL SEE HIGHS FROM THE MID 20S TO
THE LOWER 30S. THE WINDS ARE EXPECTED TO REMAIN OVER 30 MPH IN SW
MN AND NW IA INTO SUNDAY SO EXTENDED THE WIND ADVISORY INTO SUNDAY.
WITH COLD AIR CONTINUING TO FILTER IN...LOWS WILL BE IN THE TEENS.
MONDAY WILL SEE A RIDGE MOVE OVER THE AREA. WITH LIMITED MIXING AND
SOME SNOW COVER EXPECTED IN OUR ERN CWA...HIGHS IN SW MN AND NW IOWA
WILL STAY IN THE MID 20S. FARTHER WEST...WARM AIR WILL BEGIN TO MOVE
IN AND TEMPERATURES WILL RISE INTO THE LOWER 30S. AS THE RIDGE MOVES
OVER THE AREA MONDAY NIGHT...EXPECT SOME RADIATION
COOLING...ESPECIALLY ALONG AND EAST OF I29 AND LOWER MINS TO AROUND
10 ABOVE. ALONG AND WEST OF THE JAMES RIVER...INCREASING SOUTH WINDS
WILL KEEP LOWS IN THE TEENS.
A WARMING TREND CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK WITH
NEAR RECORD TEMPERATURES POSSIBLE BY THURSDAY. NO PRECIPITATION IS
EXPECTED.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
IFR TO MVFR CEILINGS OVER TAF LOCATIONS WILL GRADUALLY AND I MEAN
GRADUALLY SHIFT EAST PER RUC MOISTURE DATA. EXPECT VFR CONDITIONS
AFTER 06Z. MAIN STORY WILL BE THE WINDS INCREASING AFTER FROPA ON
SATURDAY. LOOKS LIKE RIGHT AROUND 17S FOR KHON...18Z KFSD...AND 19Z
FOR KSUX. NORTHEAST WINDS TO INCREASE QUICKLY AFTER FROPA.
&&
FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR IAZ001-012-
020-031.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR IAZ002-003-013-014-021-022-032.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT
CST TONIGHT FOR IAZ003-014-022.
MN...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR MNZ098.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY
NIGHT FOR MNZ071-072-080-081-089-090-097.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT
CST TONIGHT FOR MNZ071-072-080-081-089-090.
NE...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR NEZ013-014.
SD...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR SDZ038>040-
052>056-058>062-064>071.
WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST SUNDAY FOR
SDZ050-057-063.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1024 AM CST SAT DEC 31 2011
.UPDATE...
A SHARP MOISTURE GRADIENT REMAINS ACROSS THE SOUTHEAST COUNTIES OF
NORTH TEXAS THIS MORNING. THE PATCHY FOG THAT WAS PRESENT ACROSS
THE SOUTHEAST EARLIER HAS DISSIPATED. LOW CLOUDS WILL REMAIN
THROUGH THE MORNING BUT SHOULD BEGIN TO SCATTER OUT THIS AFTERNOON
AS DRIER AIR MIXES DOWN.
AN UNSEASONABLY WARM DAY IS SHAPING UP AROUND THE REGION WITH
ABUNDANT SUN AND AN INCREASING SOUTH TO SOUTHWEST WIND. EXPECT
AFTERNOON HIGHS IN THE LOWER AND MIDDLE 70S WITH A FEW UPPER 70S
POSSIBLE ACROSS THE WEST.
THE COLD FRONT THAT WILL MOVE THROUGH NORTH TEXAS TONIGHT IS
CURRENTLY SWEEPING ACROSS THE HIGH PLAINS...BRINGING WITH IT MUCH
COLDER TEMPERATURES AND STRONG NORTH TO NORTHWEST WINDS. THE FRONT
WILL NOT HAVE THE SAME PUNCH WHEN IT MOVES ACROSS NORTH TEXAS
TONIGHT BUT IT WILL CAUSE TEMPERATURES TO STEADILY FALL AND THE
WINDS TO INCREASE AND BECOME GUSTY...ESPECIALLY FOR THE FIRST FEW
POST-FRONTAL HOURS.
THE ONLY CHANGES NECESSARY FOR THE UPDATE WILL BE TO REMOVE THE
MENTION OF FOG FROM THE SOUTHEAST AND TO INCREASE WIND SPEEDS
BEHIND THE FRONT TONIGHT. HOWEVER...WIND SPEEDS TONIGHT SHOULD NOT
REACH WIND ADVISORY CRITERIA.
79
&&
.AVIATION...
LOW CLOUDS/FOG PROGGED TO SHUNT NORTHEAST BEFORE IT REACHES WACO.
LIFR/IFR CONDITIONS MAY PERSIST ALL DAY IN EASTERN NORTH TEXAS.
HRRR SEEMS TO HAVE A GOOD HANDLE ON STRATUS AND WILL FOLLOW ITS
GUIDANCE...SUPPORTED BY RUC SOUNDINGS AS WELL. COLD FRONT SHOULD
REACH METROPLEX NEAR SUNDOWN...AND SHIFT WINDS BACK TO THE NORTH.
LACK OF MOISTURE WILL PRODUCE CAVOK CONDITIONS WITH FROPA AND
EXPECT CLEAR SKIES TO CONTINUE SUNDAY. 84
&&
.PREV DISCUSSION... /ISSUED 359 AM CST SAT DEC 31 2011/
LOW CLOUDS AND PATCHY FOG OVER SOUTHEAST TEXAS SHOULD SPREAD INTO
THE SOUTHEASTERN PART OF NORTH TEXAS THIS MORNING. OTHERWISE...EXPECT
A WARM AND MOSTLY SUNNY LAST DAY OF THE YEAR ACROSS NORTH TEXAS.
AFTER MORNING LOWS IN THE 30S...TEMPERATURES WILL CLIMB INTO THE
70S AREA WIDE THIS AFTERNOON. A COLD FRONT THAT EXTENDED FROM
CENTRAL SOUTH DAKOTA SOUTHWEST INTO THE NORTHERN COLORADO AT 3 AM...
WILL SWEEP SOUTHEAST INTO THE WICHITA FALLS AREA BY SUNSET AND
THROUGH ALL OF NORTH TEXAS BY THE TIME WE RING IN THE NEW YEAR.
THIS FRONT WILL PROVIDE COOLER...BUT STILL DRY WEATHER...FOR A
COUPLE OF DAYS. SOUTHERLY WINDS WILL RETURN LATE MONDAY NIGHT AND
INCREASE SOME ON TUESDAY AHEAD OF THE NEXT SHORT WAVE AND COLD
FRONT. THE INCREASING SOUTHERLY WINDS TUESDAY AND LOW RELATIVE
HUMIDITIES WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS
TUESDAY. THIS FRONT WILL THEN SWEEP THROUGH WEDNESDAY WITH NO
PRECIPITATION EXPECTED ACROSS NORTH TEXAS. SOUTHERLY WINDS WILL
RETURN BY LATE THURSDAY AND YET ANOTHER FRONT IS EXPECTED FRIDAY
NIGHT/SATURDAY MORNING. AT THIS TIME IT LOOKS LIKE RAIN CHANCES
WITH THE SYSTEM WILL LIKELY BE TO THE EAST OF THE FORECAST AREA.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 73 38 60 34 56 / 5 0 0 0 0
WACO, TX 73 40 62 30 57 / 5 5 0 0 0
PARIS, TX 71 37 58 31 54 / 5 5 0 0 0
DENTON, TX 72 36 58 27 53 / 5 0 0 0 0
MCKINNEY, TX 72 37 60 30 55 / 5 0 0 0 0
DALLAS, TX 73 41 59 35 56 / 5 0 0 0 0
TERRELL, TX 71 40 59 32 57 / 5 5 0 0 0
CORSICANA, TX 72 40 62 33 57 / 5 5 0 0 0
TEMPLE, TX 73 37 61 30 57 / 5 5 0 0 0
MINERAL WELLS, TX 74 34 61 26 56 / 5 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25/79
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
515 AM CST SAT DEC 31 2011
.AVIATION...
LOW CLOUDS/FOG PROGGED TO SHUNT NORTHEAST BEFORE IT REACHES WACO.
LIFR/IFR CONDITIONS MAY PERSIST ALL DAY IN EASTERN NORTH TEXAS.
HRRR SEEMS TO HAVE A GOOD HANDLE ON STRATUS AND WILL FOLLOW ITS
GUIDANCE...SUPPORTED BY RUC SOUNDINGS AS WELL. COLD FRONT SHOULD
REACH METROPLEX NEAR SUNDOWN...AND SHIFT WINDS BACK TO THE NORTH.
LACK OF MOISTURE WILL PRODUCE CAVOK CONDITIONS WITH FROPA AND
EXPECT CLEAR SKIES TO CONTINUE SUNDAY. 84
&&
.PREV DISCUSSION... /ISSUED 359 AM CST SAT DEC 31 2011/
LOW CLOUDS AND PATCHY FOG OVER SOUTHEAST TEXAS SHOULD SPREAD INTO
THE SOUTHEASTERN PART OF NORTH TEXAS THIS MORNING. OTHERWISE...EXPECT
A WARM AND MOSTLY SUNNY LAST DAY OF THE YEAR ACROSS NORTH TEXAS.
AFTER MORNING LOWS IN THE 30S...TEMPERATURES WILL CLIMB INTO THE
70S AREA WIDE THIS AFTERNOON. A COLD FRONT THAT EXTENDED FROM
CENTRAL SOUTH DAKOTA SOUTHWEST INTO THE NORTHERN COLORADO AT 3 AM...
WILL SWEEP SOUTHEAST INTO THE WICHITA FALLS AREA BY SUNSET AND
THROUGH ALL OF NORTH TEXAS BY THE TIME WE RING IN THE NEW YEAR.
THIS FRONT WILL PROVIDE COOLER...BUT STILL DRY WEATHER...FOR A
COUPLE OF DAYS. SOUTHERLY WINDS WILL RETURN LATE MONDAY NIGHT AND
INCREASE SOME ON TUESDAY AHEAD OF THE NEXT SHORT WAVE AND COLD
FRONT. THE INCREASING SOUTHERLY WINDS TUESDAY AND LOW RELATIVE
HUMIDITIES WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS
TUESDAY. THIS FRONT WILL THEN SWEEP THROUGH WEDNESDAY WITH NO
PRECIPITATION EXPECTED ACROSS NORTH TEXAS. SOUTHERLY WINDS WILL
RETURN BY LATE THURSDAY AND YET ANOTHER FRONT IS EXPECTED FRIDAY
NIGHT/SATURDAY MORNING. AT THIS TIME IT LOOKS LIKE RAIN CHANCES
WITH THE SYSTEM WILL LIKELY BE TO THE EAST OF THE FORECAST AREA.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 73 38 60 34 56 / 5 0 0 0 0
WACO, TX 73 40 62 30 57 / 5 5 0 0 0
PARIS, TX 71 37 58 31 54 / 5 5 0 0 0
DENTON, TX 72 36 58 27 53 / 5 0 0 0 0
MCKINNEY, TX 72 37 60 30 55 / 5 0 0 0 0
DALLAS, TX 73 41 59 35 56 / 5 0 0 0 0
TERRELL, TX 71 40 59 32 57 / 5 5 0 0 0
CORSICANA, TX 72 40 62 33 57 / 5 5 0 0 0
TEMPLE, TX 73 37 61 30 57 / 5 5 0 0 0
MINERAL WELLS, TX 74 34 61 26 56 / 5 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 AM CST MON JAN 2 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
315 AM CST MON JAN 2 2012
MAIN FORECAST CONCERNS THIS PACKAGE...TEMPERATURES THRU THE
PERIOD...SMALL -SN CHANCE NORTH TUE EVENING.
DATA ANALYSIS AT 06Z HAD A BROAD...STRONG AREA OF LOW PRESSURE
CENTERED OVER WESTERN QUEBEC. TIGHT PRESSURE GRADIENT AROUND THIS
LOW EXTENDED WESTWARD ACROSS MN/IA/WI INTO THE EASTERN DAKOTAS.
WINDS WERE SLOWLY DECREASING...BUT REMAINED NORTHWEST 15-25KTS
G25-30KTS ACROSS THE UPPER MIDWEST. BROAD STRATUS CLOUD SHIELD IN
THE WAKE OF THE LOW EXTENDED WEST TO NEAR THE MN/ND BORDER TO NEAR
KDSM...WITH THE CLEARING EDGE MAKING ONLY SLOW PROGRESS EASTWARD
EARLY THIS MORNING. BROAD LOW LEVEL COLD ADVECTION ON THE NORTHWEST
FLOW SLOWLY SENDING TEMPS TOWARD MORE NORMAL VALUES FOR EARLY JAN...
BUT STILL ABOUT 10F ABOVE NORMAL.
02.00Z MODELS INITIALIZED VERY WELL AND OFFER QUITE SIMILAR
SOLUTIONS FOR TODAY THRU WED NIGHT. BIGGEST DETAIL DIFFERENCES LOOK
TO BE WITH HANDLING OF LOWER LEVEL MOISTURE/STRATUS CLOUDS/CLEARING
OVER THE REGION TODAY. DPROG/DT OF 500MB HGTS AT 02.00Z SHOWED MODEL
RUNS OF 31.00Z AND 01.00Z VERIFIED WELL ACROSS NOAM/EASTERN PAC WITH
A TREND TOWARD A COMPROMISE/BLEND OF THE EARLIER RUNS ON THE EASTERN
CONUS AND EASTERN PAC TROUGHS. THRU TODAY/TONIGHT TREND IS STRONGER/
TIGHTER CONSENSUS ON THE EASTERN CONUS TROUGH AND SLOWER WITH
SHORTWAVE HEADING INTO THE NORTHERN PLAINS. CONSENSUS REMAINS GOOD
TUE/TUE NIGHT AS THE NORTHERN PLAINS TROUGH DROPS ACROSS THE
WESTERN GREAT LAKES...TRENDING TOWARD A COMPROMISE OF THE EARLIER
RUNS ON THE STRENGTH OF THIS FEATURE. CONSENSUS IMPROVING FOR WED
WED NIGHT AS HGTS RISE/RIDGING ALOFT BUILDS INTO THE NORTHERN
PLAINS/UPPER MIDWEST...FAVORING FASTER OF EARLIER RUNS. SOMEWHAT
BETTER RUN-TO-RUN CONSISTENCY TO ECMWF THRU THE PERIOD. CHECK OF
OBS VS. MODEL DATA AT 06Z SHOWED ALL MODELS QUITE GOOD WITH THE
QUEBEC LOW AND PRESSURE GRADIENT ACROSS THE REGION. PER FOG-PRODUCT
IMAGERY AND 925-850MB MODEL RH FIELDS...MODELS HAVING SOME
DIFFICULTY WITH THE STRATUS SHIELD OVER MN/IA/WI EARLY THIS
MORNING. MODEL CONSENSUS TOO DRY WITH THE LOW LEVEL RH. EXCEPTION
IS GFS LOOKING TOO MOIST AT 925MB VS. THE SATELLITE IMAGERY. PER WV
IMAGERY...MODELS ALL APPEAR REASONABLE WITH THE SHORTWAVE DETAILS
ACROSS NOAM/EASTERN PAC. NO CLEAR MODEL FAVORITE THIS CYCLE AND
FAVORED A MODEL/ENSEMBLE CONSENSUS. IN SPITE OF SOME CLOUD ISSUES
TODAY...SHORT-TERM FCST CONFIDENCE GOOD THIS CYCLE.
FOR THE SHORT TERM...AFTER THE VIGOROUS HOLIDAY WEEKEND SYSTEM...
SHORT-TERM FOR TODAY THRU WED LOOKING RATHER QUIET. QUEBEC LOW
CONTINUES TO MOVE EAST WITH RIDGE OF HIGH PRESSURE FROM THE WESTERN
DAKOTAS DRIFTING EAST THRU THE DAY. PRESSURE GRADIENT CONTINUES TO
SLOWLY RELAX THRU THE DAY. WITH CONTINUED LOW LEVEL COLD ADVECTION/
SUBSIDENCE...GRADIENT WILL CONTINUE TO SUPPORT NORTHWEST WINDS 15-
25KT G30KTS MUCH OF THE DAY. BIGGER PROBLEM TODAY IS THE CLOUDS/
CLEARING TREND. WITH CLOUDS MUCH MORE WIDESPREAD ACROSS MN/WI/IA
THAN BULK OF MODELS...TRENDED TOWARD MORE CLOUD COVER OVER THE AREA
AT LEAST THRU THE MORNING. WITH AREA RADARS SHOWING WEAK RETURNS
AND SFC OBS OCCASIONALLY REPORTING -SN...ADDED SCT FLURRY MENTION TO
NORTHEAST HALF OF THE FCST FOR THIS MORNING. MODEL CONSENSUS
INDICATES THE MOISTURE TO BECOME VERY SHALLOW THIS AFTERNOON...
EVENTUALLY SUCCUMBING TO THE SUBSIDENCE/COLD ADVECTION. THIS APPEARS
TO BE HAPPENING EARLY THIS MORNING WITH THINNING/SCATTERING OF THE
CLOUDS OVER FAR NORTHWEST MN...WHICH MODELS SPREAD INTO THE AREA
THIS AFTERNOON. COLD/NEAR NORMAL NIGHT ON TAP FOR THE AREA TONIGHT
WITH CLEAR SKIES/LIGHT WINDS AS THE SFC RIDGE AXIS DRIFTS ACROSS THE
REGION. WITH LACK OF SNOW COVER FOR MUCH OF THE AREA...EVEN WITH
IDEAL RADIATIONAL COOLING CONDITIONS...TEMPS ONLY LOOKING TO DIP TO
NEAR THE NORMAL LOWS. STRONG LOW LEVEL WARM ADVECTION ALREADY
RETURNS FOR TUE AS THE NEXT TROUGH MOVES ACROSS THE DAKOTAS INTO MN
AND THE SFC RIDGE AXIS QUICKLY MOVES EAST OF THE REGION. THIS TROUGH
AND MID LEVEL SHORTWAVE MOVE ACROSS THE AREA TUE EVENING. SFC-700MB
MOISTURE RATHER LIMITED WITH THIS TROUGH. WHAT BETTER COLUMN
SATURATION THERE IS AND STRONGER OF FORCING/LIFT PASS ACROSS THE
NORTH END OF THE FCST AREA TUE EVENING...BUT 925-700MB LOOKS TO
REMAIN TOO DRY FOR PRECIP. LEFT A SMALL -SN CHANCE OVER THE
NORTHEAST END OF THE FCST AREA TUE EVENING TO BLEND WITH NEIGHBORING
GRIDS. QUICK AND WEAK SHOT OF LOW LEVEL COLD ADVECTION SPREADS
ACROSS THE AREA LATER TUE NIGHT/WED MORNING. LOW LEVEL WARM
ADVECTION RETURNS/INCREASES FOR LATER WED THRU WED NIGHT WITH THE
STORM TRACK SHIFTED INTO CENTRAL CAN. BULK OF THIS GOES INTO
WARMING...WITH GOOD MODEL CONSENSUS FOR 925MB TEMPS TO BE IN THE 0C
TO +6C RANGE EAST TO WEST ACROSS THE FCST AREA BY 12Z THU.
CONSIDERED A NON-DIURNAL TEMP TREND FOR WED NIGHT BUT PRESSURE
GRADIENT ON THE WEAK SIDE AND SFC WINDS THRU WED NIGHT LOOKING TO
MOSTLY BE 5KTS OR LESS.
WITH CLOUDS MUCH OF THE DAY TODAY AND CONTINUED AT LEAST WEAK LOW
LEVEL COLD ADVECTION...TEMPS TO BE NEARLY STEADY TODAY. BASED ON 09Z
READINGS UNDER THE CLOUDS/LIMITED SNOW COVER...FAVORED WARMER OF
GUIDANCE HIGHS TODAY. FAVORED A BLEND OF GUIDANCE LOWS/HIGHS FOR
TONIGHT THRU TUE NIGHT. WITH SOME SUN...MIXING AND MOSTLY SNOW-FREE
GROUND...TRENDED TOWARD WARMER OF GUIDANCE HIGHS FOR WED. FAVORED
A BLEND OF THE GUIDANCE LOWS FOR WED NIGHT FOR NOW.
.LONG TERM...THURSDAY THROUGH SUNDAY
315 AM CST MON JAN 2 2012
DAY 4-7 FCST CONFIDENCE AVERAGE TO GOOD. 02.00Z MEDIUM RANGE MODELS
IN GOOD AGREEMENT FOR THE RIDGING ALOFT TO BUILD ACROSS THE REGION
THU THEN TROUGHING TO MOVE INTO THE NORTHERN PLAINS FRI. STORM TRACK
REMAINS IN CENTRAL CAN THU WITH MDT/STRONG LOW LEVEL WARM ADVECTION
CONTINUING OVER THE AREA THU INTO THU NIGHT. 925MB TEMPS BY 00Z FRI
IN THE +2C TO +10C RANGE. SFC PRESSURE GRADIENT REMAINS MODERATE...
WITH LIGHTER WINDS FOR MIXING. MODEL SOUNDINGS SHOWING A RATHER
IMPRESSIVE LOW LEVEL INVERSION THU...ALONG WITH HIGHER 500-300MB RH
AND POTENTIAL FOR CIRRUS CLOUDS. WEAK/MDT LOWER LEVEL COLD ADVECTION
SPREADS IN FOR FRI BEHIND A SFC TROUGH/FRONTAL PASSAGE BUT 925MB
TEMPS REMAIN ABOVE 0C/WELL ABOVE NORMAL THRU 00Z SAT. TEMPS THU/FRI
CONTINUE TO TREND TOWARD MUCH ABOVE NORMAL FOR EARLY JAN BUT JUST
HOW MUCH REMAINS IN QUESTION. FOR NOW FAVORED THE MODEL CONSENSUS ON
THU/FRI HIGHS GIVEN SIGNIFICANT IMPACT ANY CLOUDS OR STRENGTH OF
MIXING WINDS COULD HAVE ON THEM. HGTS FALL ACROSS THE NORTH-CENTRAL
CONUS FOR SAT/SUN WITH BROAD TROUGHING DEVELOPING OVER CENTRAL/
EASTERN NOAM. SECONDARY TROUGH/COLD FRONT DROPS THRU THE REGION SAT
WITH THE AREA RECEIVING A GLANCING BLOW OF COLDER AIR. PATTERN
REMAINS PROGRESSIVE WITH LOWER LEVEL WARM ADVECTION ALREADY
RETURNING FOR SUN AS THE STORM TRACK REMAINS NORTH IN CANADA. SAT/
SUN LOOKING TO REMAIN DRY WITH TEMPS NEAR OR ABOVE NORMAL. A MODEL
CONSENSUS/BLEND FOR THE DAY 6/7 FCST GRIDS LOOKS GOOD AT THIS TIME.
&&
.AVIATION...THROUGH 06Z TUESDAY
1137 PM CST SUN JAN 1 2012
MAIN FORECAST CONCERNS REMAIN ON WINDS THROUGH MONDAY AND TIMING OF
CLEARING TREND. PRESSURE GRADIENT WILL REMAIN RATHER TIGHT THROUGH
MONDAY AND STILL EXPECT THE NORTHWEST WINDS TO GUST TO NEAR 30 TO 35
KNOTS THROUGH AT LEAST MID AFTERNOON MONDAY BEFORE DIMINISHING
RAPIDLY DURING THE EARLY EVENING HOURS AS RIDGE AXIS BUILDS INTO THE
AREA. CEILINGS HAVE BEEN VERY CONSISTENT THIS EVENING IN THE
025K-035K FOOT RANGE. LOOKING UPSTREAM OF THE TAF SITES FEEL THIS
TREND WILL CONTINUE THROUGH THE OVERNIGHT HOURS AND THEN BEGIN TO
RISE INTO VFR AFTER 14Z MONDAY. LATEST 02.03Z RUC BUFKIT SOUNDINGS
SHOW CLOUDS TO BEGIN TO SCATTERED OUT MONDAY MORNING FROM THE WEST.
THIS A LITTLE SLOWER THAN PREVIOUSLY THOUGHT AND DID BACK CLEARING
UP AT KRST UNTIL 16Z...WITH KLSE AROUND 20Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CST MON JAN 2 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 PM CST SUN JAN 1 2012
.SHORT TERM...
1137 PM CST SUN JAN 1 2012
ALTHOUGH PRESSURE GRADIENT WILL REMAIN TIGHT OVERNIGHT...SURFACE
REPORTS INDICATE WINDS HAVE DROPPED JUST BELOW ADVISORY CRITERIA.
THUS WILL BE ALLOWING THE WIND ADVISORY TO EXPIRE AS SCHEDULED AT
MIDNIGHT. STILL COULD SEE SOME ISOLATED GUSTS TO AROUND 40
MPH. WILL HAVE UPDATED PRODUCTS OUR BY THE TOP OF THE HOUR.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
304 PM CST SUN JAN 1 2012
01.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ARE GENERALLY IN GOOD
AGREEMENT THROUGH THE ENTIRE LONG TERM PERIOD. UPPER RIDGING THAT
HAS BEEN PRESENT OVER THE WESTERN U.S. IS STILL SHOWN TO FLATTEN OUT
AND PUSH EAST...IN RESPONSE TO A FAIRLY POTENT TROUGH COMING INTO
SOUTHWEST CANADA AROUND 00Z FRIDAY. THIS UPPER RIDGING WILL BRING
WITH IT 850MB TEMPS THAT ARE AROUND 2 STANDARD DEVIATIONS ABOVE
NORMAL INTO THE FORECAST AREA FRIDAY MORNING. THE SURFACE WARM FRONT
LEADING THE WARMER AIR LOOKS TO MOVE THROUGH THE AREA THURSDAY
NIGHT. MAY SEE SOME MID AND HIGH CLOUDS AHEAD OF THE WARM FRONT FOR
WEDNESDAY NIGHT AND THURSDAY...BUT NO PRECIPITATION IS ANTICIPATED
DUE TO PLENTY OF LOW LEVEL DRY AIR. COLD FRONT MOVES THROUGH DURING
THE DAY FRIDAY WITH LITTLE FANFARE. THE FRONT WILL BRING IN SOME
COOLER AIR...KNOCKING 850MB TEMPS DOWN FROM THE 8-10C READINGS AT
12Z FRIDAY TO PERHAPS AS COOL AS 2-6C BY 00Z SATURDAY. HOWEVER...THE
FRONT MAY ACTUALLY HELP TO PRODUCE BETTER MIXING. WITH MOSTLY SUNNY
SKIES ANTICIPATED ON FRIDAY...READINGS IN THE 40S ARE LIKELY WITH
50S CERTAINLY NOT OUT OF THE QUESTION. COLDEST READINGS EXPECTED
OVER NORTH CENTRAL WISCONSIN...WHILE WARMEST READINGS WOULD OCCUR
OVER NORTHEAST IOWA.
FOR NEXT WEEKEND...BROAD TROUGHING DEVELOPS FROM THE SOUTHWESTERN
U.S. INTO ONTARIO...WITH SOME INDICATIONS THAT IT MAY SPLIT INTO TWO
PIECES. MUCH OF THIS TROUGHING FORMS FROM THAT POTENT TROUGH...WHICH
IS DIGGING INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA ON
FRIDAY. THIS TROUGHING COMING INTO THE FORECAST AREA WILL ALLOW FOR
COLDER AIR TO MOVE INTO THE AREA. 850MB TEMPS ARE PROGGED TO DROP TO
-6 TO -10C BY 00Z SUNDAY AND AT LEAST -10 TO -14C BY 00Z MONDAY.
NOTE...THE 01.12Z ECMWF NOW SHOWS WARMER CONDITIONS...WITH 850MB
TEMPS ONLY DROPPING TO 0 TO -3C BY 00Z SUNDAY AND -4 TO -8C BY 00Z
MONDAY. THEREFORE...IT IS POSSIBLE THAT THE WEEKEND MIGHT BE A
LITTLE WARMER THAN FORECAST. DESPITE THE COOLING...NOT A LOT OF
MOISTURE LOOKS TO ACCOMPANYING THE TROUGH...SO DRY CONDITIONS ARE
FORECAST AT THIS TIME.
&&
.AVIATION...THROUGH 06Z TUESDAY
1137 PM CST SUN JAN 1 2012
MAIN FORECAST CONCERNS REMAIN ON WINDS THROUGH MONDAY AND TIMING OF
CLEARING TREND. PRESSURE GRADIENT WILL REMAIN RATHER TIGHT THROUGH
MONDAY AND STILL EXPECT THE NORTHWEST WINDS TO GUST TO NEAR 30 TO 35
KNOTS THROUGH AT LEAST MID AFTERNOON MONDAY BEFORE DIMINISHING
RAPIDLY DURING THE EARLY EVENING HOURS AS RIDGE AXIS BUILDS INTO THE
AREA. CEILINGS HAVE BEEN VERY CONSISTENT THIS EVENING IN THE
025K-035K FOOT RANGE. LOOKING UPSTREAM OF THE TAF SITES FEEL THIS
TREND WILL CONTINUE THROUGH THE OVERNIGHT HOURS AND THEN BEGIN TO
RISE INTO VFR AFTER 14Z MONDAY. LATEST 02.03Z RUC BUFKIT SOUNDINGS
SHOW CLOUDS TO BEGIN TO SCATTERED OUT MONDAY MORNING FROM THE WEST.
THIS A LITTLE SLOWER THAN PREVIOUSLY THOUGHT AND DID BACK CLEARING UP
AT KRST UNTIL 16Z...WITH KLSE AROUND 20Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1137 PM CST SUN JAN 1 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1029 PM CST SUN JAN 1 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...AM GOING TO BUFFER THE WS.W FOR VILAS WITH A WW.Y FOR
ONEIDA...FOREST...AND FLORENCE COUNTIES. OBS FM N-C WI CONT TO
SUGGEST NASTY CONDITIONS DUE TO SHSN AND SOME BLSN/DRSN. WINDS AT
925/850 MB STILL IN THE PROCESS OF VEERING INTO A MORE FAVORABLE
TRAJECTORY...AND COLDER AIR ARRIVING OVER THE LAKE. RADAR MOSAIC
SUGGESTS AN INCR IN LAKE-EFFECT COMING INLAND FM WRN LAKE
SUPERIOR THE PAST COUPLE HRS. MOST IMPORTANTLY...THE AIR UPSTREAM
FM THE LAKE IS STILL MOIST...AND SYNOPTIC FORCING STILL GENERATING
SOME SHSN NW OF THE LAKE. SO THE ARRIVAL OF THE COLDER AIR WON/T
BE OFFSET BY DRYING AS IS OFTEN THE CASE. THIS SURE ISN/T A
GIVEN...BUT HEADLINES FOR LAKE-EFFECT IN N-C WI GENERALLY ARE NOT.
GIVEN THE OVERALL EVOLUTION OF THE SITN...CONDITIONS WL LIKELY BE
BAD ENOUGH TO SUPPORT A HEADLINE RATHER THAN TRYING TO GET BY WITH
JUST STATEMENTS.
WL MAKE SOME TWEAKS...BUT NO SIG CHGS...TO THE FCST FOR THE REST
OF THE AREA. WINDS STILL NOT COMING UP MUCH IN DOOR COUNTY. BUT A
CONT VEERING WL BRING THEM TO A MORE FAVORABLE NNWLY TRAJECTORY...
AND CAA SHOULD DEEPEN THE MIXED LAYER. SO WL STAY THE COURSE WITH
THE DOOR COUNTY WI.Y.
UPDATED PRODUCT SUITE WL BE OUT ASAP. NO CHGS TO THE NPW NOW...WL
FRESHEN THE WORDING LATER...BUT DON/T ANTICIPATE CONTENT CHGS TO
THAT YET.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 643 PM CST SUN JAN 1 2012...
UPDATE...NOT MEETING WIND ADVISORY CRITERIA ANYWHERE IN THE FCST
AREA. THE CLOSEST WAS THE MOST RECENT IMT OB...BUT EVEN THAT WAS
BLO CRITERIA. SOME INCR IN CAA EXPECTED DURING THE EVENING. BUT
925 MPH WINDS PROGGED TO PEAK WITHIN THE NEXT FEW HRS AND THEN
START TO SLOWLY EDGE BACK DOWN. GIVEN HOW FAR WE ARE FROM ADVISORY
CRITERIA AT MOST LCNS RIGHT NOW...HARD TO SEE ANYTHING MORE THAN
AN ISOLD OB GETTING EVEN CLOSE. IT/S CERTAINLY NOT GOING TO BE A
COMFORTABLE EVENING TO BE OUTSIDE AND DON/T WANT TO SPLIT HAIRS
OVER EXACT CRITERIA...BUT MY OVERALL FEEL FOR THE SITN IS THAT WE
JUST AREN/T CLOSE ENOUGH TO TRY AND RIDE THE ADVISORY UNTIL
MIDNIGHT. SO WL DROP IT FOR ALL BUT THE DOOR.
CAA ALOFT ARRIVING ALOFT OVER THE UNFROZEN NRN BAY WL DEEPEN THE
MIXING OVER THE DOOR...SO SHOULD STILL GET SOME INCR IN WINDS
THERE. WL MAINTAIN THE ADVISORY FOR DOOR COUNTY.
UPDATED PRODUCT SUITE WL BE OUT ASAP.
SKOWRONSKI
DISCUSSION ISSUED AT 514 PM CST SUN JAN 1 2012...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING TO THE NORTHEAST OVER LAKE HURON THIS AFTERNOON WHILE HIGH
PRESSURE HAS SETTLED OVER THE FRONT RANGE OF THE ROCKIES. STRONG
SHORTWAVE OVER SOUTHERN WISCONSIN IS CONTRIBUTING TO WIDESPREAD SNOW
SHOWERS AND FLURRIES ACROSS THE REGION...BUT THE SNOW SHOWERS EXIST
ALL THE WAY BACK TO NORTHERN MINNESOTA AND SW ONTARIO. LAKE EFFECT
SNOWS REMAIN NORTH OF THE U.P. BORDER SO FAR...BUT WITH SOME
IMPRESSIVE BANDS ON THE MQT RADAR. MEANWHILE...WIND GUSTS THIS
AFTERNOON HAVE REMAINED WELL BELOW ADVISORY CRITERIA SO FAR. HAVE
HAD A FEW GUSTS IN THE 34-37 KT RANGE OVER CENTRAL WISCONSIN LATE
THIS MORNING...BUT HAVE SINCE DIMINISHED. HEADLINES AND SNOW
AMOUNTS REMAIN THE MAIN FORECAST CONCERN IN THE SHORT TERM.
TONIGHT...LOW PRESSURE WILL EXIT THE REGION INTO QUEBEC WHILE ARCTIC
HIGH PRESSURE MOVES EAST OVER THE GREAT PLAINS. A TIGHT PRESSURE
GRADIENT WILL REMAIN IN PLACE BETWEEN THESE TWO FEATURES WITH 0-1KM
AGL WIND SPEEDS AROUND 35 KTS. DESPITE THE COLD ADVECTION
TODAY...WIND GUSTS HAVE BEHAVED AND HAVE ONLY BRIEFLY APPROACHED
ADVISORY CRITERIA OVER CENTRAL WISCONSIN. WILL MONITOR WIND GUSTS
UNTIL THE LAST MINUTE BEFORE MAKING HEADLINE DECISIONS ON THE WIND
ADVISORY. AFTER COORDINATION...WILL LEAVE WIND HEADLINES IN PLACE
AS A TIGHT PRESSURE GRADIENT UPSTREAM AND COLD ADVECTION CONTINUES.
STILL PLENTY GOING ON BESIDES THE GUSTY WINDS. SHORTWAVE TROUGH
NEAR MSN WILL BE EXITING OVER SOUTHERN LAKE MICHIGAN DURING THE
EVENING. ANOTHER SHEARED WAVE OVER LAKE WINNIPEG WILL DIVE
SOUTHEAST OVER THE NORTHERN MISSISSIPPI VALLEY TONIGHT AND KEEP WEAK
QG FORCING IN PLACE. COMBINED WITH 1-3SM SNOW OBS ALL THE WAY NORTH
OF INTERNATIONAL FALLS AND SATURATION OF THE COLUMN ABOVE THE -10C
LINE IN PROGGED SOUNDINGS...WILL LEAVE A SCATTERED SNOW SHOWER
MENTION ACROSS THE FORECAST AREA FOR THE DURATION OF THE EVENING.
THE BIGGEST IMPACT WILL BE THE LAKE EFFECT SNOW OVER NORTH-CENTRAL
WISCONSIN. CONDITIONS WILL BE IMPROVING FOR SIGNIFICANT
ACCUMULATIONS THROUGH THE NIGHT. MAY NOT BE A WHOLE LOT OF IMPACT
THIS EVENING...AS WIND DIRECTIONS OF 320-330 ARE NOT CONDUCIVE FOR
ACCUMS EXCEPT ALONG THE U.P. BORDER. BUT TRAJECTORIES WILL VEER
SLIGHTLY TO 340 DEGREES BY 12Z MONDAY. WITH DELTA T/S IN THE UPPER
TEENS AND 850-700MB MOISTURE OF 80 PCT...SHOULD SEE GOOD DENDRITIC
SNOW GROWTH TO GENERATE A HALF INCH TO ONE INCH PER HOUR SNOWFALL
RATES BY THIS TIME. WILL LOWER SNOW AMOUNTS IN THE EVENING...BUT
KEEP THEM AROUND 2-3 INCHES DURING THE OVERNIGHT PERIOD. THIS WILL
YIELD 3-5 INCH AMOUNTS...HIGHEST OVER THE NORTHERN PART OF VILAS
COUNTY.
MONDAY...THE LAKE EFFECT SHOW WILL CONTINUE OVER N-C WISCONSIN
DURING THE MORNING. BUT CONDITIONS WILL TURN INCREASINGLY HOSTILE
DURING THE 15-18Z TIMEFRAME AS DRY ARCTIC AIR FLOWS OVER WESTERN
LAKE SUPERIOR. AS A RESULT...SNOWFALL RATES SHOULD BE DIMINISHING
BY MIDDAY AND THROUGH THE AFTERNOON...AS THE DRY AIR SURGES
SOUTHEAST. WILL GO WITH AN ADDITIONAL 2-4 INCHES IN THE FORECAST.
CLOUDY TO MOSTLY CLOUDY CONDITIONS WILL EXIST ELSEWHERE. LEFT AN
ISOLATED FLURRY MENTION GOING FOR THE MORNING BEFORE THE DRIER AIR
ARRIVES. SOME BREAKS IN THE CLOUDS ARE LIKELY MID TO LATE
AFTERNOON. HIGHS RANGING FROM THE LOWER TEENS TO LOWER 20S.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
SURFACE RIDGE WILL GRADUALLY DRIFT INTO THE FORECAST AREA MONDAY
NIGHT. SUBSTANTIAL DRYING AND STRONG SUBSIDENCE SHOULD PRETTY
MUCH PUT AN END TO ANY LAKE EFFECT SNOW FOR VILAS COUNTY BY EARLY
MONDAY EVENING. JUST KEPT A FEW LINGERING FLURRIES FOR FAR
NORTHERN VILAS BEFORE 06Z THEN DRY THERAFTER. STILL APPEARS MONDAY
NIGHT WILL BE THE COLDEST NIGHT WE HAVE SEEN THIS SEASON WITH MIN
TEMPS EASILY FALLING INTO THE MIDDLE NEGATIVE TEENS ACROSS
NORTHCENTRAL OVERNIGHT GIVEN FRESH SNOW COVER THAT WAS RECEIEIVED EARLY
SUNDAY.
SHORTWAVE DISTURBANCE THEN QUICKLY DIVES SOUTHEAST INTO THE
WESTERN GREAT LAKES BY 00Z WEDNESDAY. AFTER A SUNNY AND COLD
START...WARM ADVECTION AHEAD OF THIS SYSTEM WILL LIKELY BRING IN
SOME MID TO HIGH-LEVEL CLOUDS DURING THE DAY ON TUESDAY. GIVEN THE
COLD START AND INCREASING CLOUDS LATER IN THE DAY...MAX TEMPS WILL
LIKELY NOT BE ABLE RISE MUCH PAST THE MIDDLE TEENS. AS PER
PREVIOUS FORECAST...STILL APPEARS LOW CHANCE POPS ARE WARRANTED
FOR FOR AT LEAST THE NORTHERN HALF OF THE FORECAST AREA. APPEARS
SYSTEM MAY BE A BIT FASTER THAN PREVIOUS MODEL RUNS THUS FOCUSED
HIGHEST POPS IN THE 00Z TO 06Z TIME FRAME. PRECIP AMOUNTS APPEAR
MINIMAL WITH LIGHT SNOW OR SNOW SHOWERS PROVIDING LITTLE IF ANY
ACCUMULATION OVERNIGHT.
DURING THE LATER HALF OF THE WORK WEEK BROAD RIDGE OVER THE
WESTERN CONUS GRADUALLY FLATTENS AND BECOMES MORE ZONAL AS SEVERAL
PIECES OF ENERGY MOVE ONSHORE OVER THE WEST COAST OF THE U.S. THIS
SHOULD LEAD TO A GENERAL BENIGN PERIOD WITH TEMPERATURES AT OR
ABOVE NORMAL STARTING WEDNESDAY...AND MODERATING FURTHER TO NEAR
40 BY WEEKS END. FAIRLY LARGE DESCREPANCY IN THE MEDIUM RANGE
MODELS FOR FRIDAY INTO THE WEEKEND ON SYSTEM MOVING ACROSS
SOUTHERN CANADA. PREFER MUCH WEAKER AND MORE ZONAL-LOOKING
ECMWF/CANADIAN. THUS KEPT FORECAST MAINLY DRY AND LEANED SLIGHTLY
WARMER THAN MODEL BLEND ESPECIALLY FOR SATURDAY.
&&
.AVIATION...LITTLE CHG IN CONDITIONS EXPECTED THE NEXT 12 HRS. SCT
SW- WL GRADUALLY DIMINISH TO SW-- EXCEPT IN THE SNOWBELT. WENT A
LITTLE SLOWER THAN GUID IS INDICATING FOR CLEARING TOMORROW GIVEN
FLOW DOWN OFF SUPERIOR.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR WIZ010>012.
WIND ADVISORY UNTIL 6 PM CST MONDAY FOR WIZ022.
WINTER STORM WARNING UNTIL 3 PM CST MONDAY FOR WIZ005.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
846 PM CST SUN JAN 1 2012
.UPDATE...AM GOING TO BUFFER THE WS.W FOR VILAS WITH A WW.Y FOR
ONEIDA...FOREST...AND FLORENCE COUNTIES. OBS FM N-C WI CONT TO
SUGGEST NASTY CONDITIONS DUE TO SHSN AND SOME BLSN/DRSN. WINDS AT
925/850 MB STILL IN THE PROCESS OF VEERING INTO A MORE FAVORABLE
TRAJECTORY...AND COLDER AIR ARRIVING OVER THE LAKE. RADAR MOSAIC
SUGGESTS AN INCR IN LAKE-EFFECT COMING INLAND FM WRN LAKE
SUPERIOR THE PAST COUPLE HRS. MOST IMPORTANTLY...THE AIR UPSTREAM
FM THE LAKE IS STILL MOIST...AND SYNOPTIC FORCING STILL GENERATING
SOME SHSN NW OF THE LAKE. SO THE ARRIVAL OF THE COLDER AIR WON/T
BE OFFSET BY DRYING AS IS OFTEN THE CASE. THIS SURE ISN/T A
GIVEN...BUT HEADLINES FOR LAKE-EFFECT IN N-C WI GENERALLY ARE NOT.
GIVEN THE OVERALL EVOLUTION OF THE SITN...CONDITIONS WL LIKELY BE
BAD ENOUGH TO SUPPORT A HEADLINE RATHER THAN TRYING TO GET BY WITH
JUST STATEMENTS.
WL MAKE SOME TWEAKS...BUT NO SIG CHGS...TO THE FCST FOR THE REST
OF THE AREA. WINDS STILL NOT COMING UP MUCH IN DOOR COUNTY. BUT A
CONT VEERING WL BRING THEM TO A MORE FAVORABLE NNWLY TRAJECTORY...
AND CAA SHOULD DEEPEN THE MIXED LAYER. SO WL STAY THE COURSE WITH
THE DOOR COUNTY WI.Y.
UPDATED PRODUCT SUITE WL BE OUT ASAP. NO CHGS TO THE NPW NOW...WL
FRESHEN THE WORDING LATER...BUT DON/T ANTICIPATE CONTENT CHGS TO
THAT YET.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 643 PM CST SUN JAN 1 2012...
UPDATE...NOT MEETING WIND ADVISORY CRITERIA ANYWHERE IN THE FCST
AREA. THE CLOSEST WAS THE MOST RECENT IMT OB...BUT EVEN THAT WAS
BLO CRITERIA. SOME INCR IN CAA EXPECTED DURING THE EVENING. BUT
925 MPH WINDS PROGGED TO PEAK WITHIN THE NEXT FEW HRS AND THEN
START TO SLOWLY EDGE BACK DOWN. GIVEN HOW FAR WE ARE FROM ADVISORY
CRITERIA AT MOST LCNS RIGHT NOW...HARD TO SEE ANYTHING MORE THAN
AN ISOLD OB GETTING EVEN CLOSE. IT/S CERTAINLY NOT GOING TO BE A
COMFORTABLE EVENING TO BE OUTSIDE AND DON/T WANT TO SPLIT HAIRS
OVER EXACT CRITERIA...BUT MY OVERALL FEEL FOR THE SITN IS THAT WE
JUST AREN/T CLOSE ENOUGH TO TRY AND RIDE THE ADVISORY UNTIL
MIDNIGHT. SO WL DROP IT FOR ALL BUT THE DOOR.
CAA ALOFT ARRIVING ALOFT OVER THE UNFROZEN NRN BAY WL DEEPEN THE
MIXING OVER THE DOOR...SO SHOULD STILL GET SOME INCR IN WINDS
THERE. WL MAINTAIN THE ADVISORY FOR DOOR COUNTY.
UPDATED PRODUCT SUITE WL BE OUT ASAP.
SKOWRONSKI
DISCUSSION ISSUED AT 514 PM CST SUN JAN 1 2012...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING TO THE NORTHEAST OVER LAKE HURON THIS AFTERNOON WHILE HIGH
PRESSURE HAS SETTLED OVER THE FRONT RANGE OF THE ROCKIES. STRONG
SHORTWAVE OVER SOUTHERN WISCONSIN IS CONTRIBUTING TO WIDESPREAD SNOW
SHOWERS AND FLURRIES ACROSS THE REGION...BUT THE SNOW SHOWERS EXIST
ALL THE WAY BACK TO NORTHERN MINNESOTA AND SW ONTARIO. LAKE EFFECT
SNOWS REMAIN NORTH OF THE U.P. BORDER SO FAR...BUT WITH SOME
IMPRESSIVE BANDS ON THE MQT RADAR. MEANWHILE...WIND GUSTS THIS
AFTERNOON HAVE REMAINED WELL BELOW ADVISORY CRITERIA SO FAR. HAVE
HAD A FEW GUSTS IN THE 34-37 KT RANGE OVER CENTRAL WISCONSIN LATE
THIS MORNING...BUT HAVE SINCE DIMINISHED. HEADLINES AND SNOW
AMOUNTS REMAIN THE MAIN FORECAST CONCERN IN THE SHORT TERM.
TONIGHT...LOW PRESSURE WILL EXIT THE REGION INTO QUEBEC WHILE ARCTIC
HIGH PRESSURE MOVES EAST OVER THE GREAT PLAINS. A TIGHT PRESSURE
GRADIENT WILL REMAIN IN PLACE BETWEEN THESE TWO FEATURES WITH 0-1KM
AGL WIND SPEEDS AROUND 35 KTS. DESPITE THE COLD ADVECTION
TODAY...WIND GUSTS HAVE BEHAVED AND HAVE ONLY BRIEFLY APPROACHED
ADVISORY CRITERIA OVER CENTRAL WISCONSIN. WILL MONITOR WIND GUSTS
UNTIL THE LAST MINUTE BEFORE MAKING HEADLINE DECISIONS ON THE WIND
ADVISORY. AFTER COORDINATION...WILL LEAVE WIND HEADLINES IN PLACE
AS A TIGHT PRESSURE GRADIENT UPSTREAM AND COLD ADVECTION CONTINUES.
STILL PLENTY GOING ON BESIDES THE GUSTY WINDS. SHORTWAVE TROUGH
NEAR MSN WILL BE EXITING OVER SOUTHERN LAKE MICHIGAN DURING THE
EVENING. ANOTHER SHEARED WAVE OVER LAKE WINNIPEG WILL DIVE
SOUTHEAST OVER THE NORTHERN MISSISSIPPI VALLEY TONIGHT AND KEEP WEAK
QG FORCING IN PLACE. COMBINED WITH 1-3SM SNOW OBS ALL THE WAY NORTH
OF INTERNATIONAL FALLS AND SATURATION OF THE COLUMN ABOVE THE -10C
LINE IN PROGGED SOUNDINGS...WILL LEAVE A SCATTERED SNOW SHOWER
MENTION ACROSS THE FORECAST AREA FOR THE DURATION OF THE EVENING.
THE BIGGEST IMPACT WILL BE THE LAKE EFFECT SNOW OVER NORTH-CENTRAL
WISCONSIN. CONDITIONS WILL BE IMPROVING FOR SIGNIFICANT
ACCUMULATIONS THROUGH THE NIGHT. MAY NOT BE A WHOLE LOT OF IMPACT
THIS EVENING...AS WIND DIRECTIONS OF 320-330 ARE NOT CONDUCIVE FOR
ACCUMS EXCEPT ALONG THE U.P. BORDER. BUT TRAJECTORIES WILL VEER
SLIGHTLY TO 340 DEGREES BY 12Z MONDAY. WITH DELTA T/S IN THE UPPER
TEENS AND 850-700MB MOISTURE OF 80 PCT...SHOULD SEE GOOD DENDRITIC
SNOW GROWTH TO GENERATE A HALF INCH TO ONE INCH PER HOUR SNOWFALL
RATES BY THIS TIME. WILL LOWER SNOW AMOUNTS IN THE EVENING...BUT
KEEP THEM AROUND 2-3 INCHES DURING THE OVERNIGHT PERIOD. THIS WILL
YIELD 3-5 INCH AMOUNTS...HIGHEST OVER THE NORTHERN PART OF VILAS
COUNTY.
MONDAY...THE LAKE EFFECT SHOW WILL CONTINUE OVER N-C WISCONSIN
DURING THE MORNING. BUT CONDITIONS WILL TURN INCREASINGLY HOSTILE
DURING THE 15-18Z TIMEFRAME AS DRY ARCTIC AIR FLOWS OVER WESTERN
LAKE SUPERIOR. AS A RESULT...SNOWFALL RATES SHOULD BE DIMINISHING
BY MIDDAY AND THROUGH THE AFTERNOON...AS THE DRY AIR SURGES
SOUTHEAST. WILL GO WITH AN ADDITIONAL 2-4 INCHES IN THE FORECAST.
CLOUDY TO MOSTLY CLOUDY CONDITIONS WILL EXIST ELSEWHERE. LEFT AN
ISOLATED FLURRY MENTION GOING FOR THE MORNING BEFORE THE DRIER AIR
ARRIVES. SOME BREAKS IN THE CLOUDS ARE LIKELY MID TO LATE
AFTERNOON. HIGHS RANGING FROM THE LOWER TEENS TO LOWER 20S.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
SURFACE RIDGE WILL GRADUALLY DRIFT INTO THE FORECAST AREA MONDAY
NIGHT. SUBSTANTIAL DRYING AND STRONG SUBSIDENCE SHOULD PRETTY
MUCH PUT AN END TO ANY LAKE EFFECT SNOW FOR VILAS COUNTY BY EARLY
MONDAY EVENING. JUST KEPT A FEW LINGERING FLURRIES FOR FAR
NORTHERN VILAS BEFORE 06Z THEN DRY THERAFTER. STILL APPEARS MONDAY
NIGHT WILL BE THE COLDEST NIGHT WE HAVE SEEN THIS SEASON WITH MIN
TEMPS EASILY FALLING INTO THE MIDDLE NEGATIVE TEENS ACROSS
NORTHCENTRAL OVERNIGHT GIVEN FRESH SNOW COVER THAT WAS RECEIEIVED EARLY
SUNDAY.
SHORTWAVE DISTURBANCE THEN QUICKLY DIVES SOUTHEAST INTO THE
WESTERN GREAT LAKES BY 00Z WEDNESDAY. AFTER A SUNNY AND COLD
START...WARM ADVECTION AHEAD OF THIS SYSTEM WILL LIKELY BRING IN
SOME MID TO HIGH-LEVEL CLOUDS DURING THE DAY ON TUESDAY. GIVEN THE
COLD START AND INCREASING CLOUDS LATER IN THE DAY...MAX TEMPS WILL
LIKELY NOT BE ABLE RISE MUCH PAST THE MIDDLE TEENS. AS PER
PREVIOUS FORECAST...STILL APPEARS LOW CHANCE POPS ARE WARRANTED
FOR FOR AT LEAST THE NORTHERN HALF OF THE FORECAST AREA. APPEARS
SYSTEM MAY BE A BIT FASTER THAN PREVIOUS MODEL RUNS THUS FOCUSED
HIGHEST POPS IN THE 00Z TO 06Z TIME FRAME. PRECIP AMOUNTS APPEAR
MINIMAL WITH LIGHT SNOW OR SNOW SHOWERS PROVIDING LITTLE IF ANY
ACCUMULATION OVERNIGHT.
DURING THE LATER HALF OF THE WORK WEEK BROAD RIDGE OVER THE
WESTERN CONUS GRADUALLY FLATTENS AND BECOMES MORE ZONAL AS SEVERAL
PIECES OF ENERGY MOVE ONSHORE OVER THE WEST COAST OF THE U.S. THIS
SHOULD LEAD TO A GENERAL BENIGN PERIOD WITH TEMPERATURES AT OR
ABOVE NORMAL STARTING WEDNESDAY...AND MODERATING FURTHER TO NEAR
40 BY WEEKS END. FAIRLY LARGE DESCREPANCY IN THE MEDIUM RANGE
MODELS FOR FRIDAY INTO THE WEEKEND ON SYSTEM MOVING ACROSS
SOUTHERN CANADA. PREFER MUCH WEAKER AND MORE ZONAL-LOOKING
ECMWF/CANADIAN. THUS KEPT FORECAST MAINLY DRY AND LEANED SLIGHTLY
WARMER THAN MODEL BLEND ESPECIALLY FOR SATURDAY.
&&
.AVIATION...LITTLE CHG IN CONDITIONS EXPECTED TNGT AS SCT SW-/SW--
CONT ACRS THE AREA.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST MONDAY FOR WIZ010>012.
WIND ADVISORY UNTIL 6 PM CST MONDAY FOR WIZ022.
WINTER STORM WARNING UNTIL 3 PM CST MONDAY FOR WIZ005.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
643 PM CST SUN JAN 1 2012
.UPDATE...NOT MEETING WIND ADVISORY CRITERIA ANYWHERE IN THE FCST
AREA. THE CLOSEST WAS THE MOST RECENT IMT OB...BUT EVEN THAT WAS
BLO CRITERIA. SOME INCR IN CAA EXPECTED DURING THE EVENING. BUT
925 MPH WINDS PROGGED TO PEAK WITHIN THE NEXT FEW HRS AND THEN
START TO SLOWLY EDGE BACK DOWN. GIVEN HOW FAR WE ARE FROM ADVISORY
CRITERIA AT MOST LCNS RIGHT NOW...HARD TO SEE ANYTHING MORE THAN
AN ISOLD OB GETTING EVEN CLOSE. IT/S CERTAINLY NOT GOING TO BE A
COMFORTABLE EVENING TO BE OUTSIDE AND DON/T WANT TO SPLIT HAIRS
OVER EXACT CRITERIA...BUT MY OVERALL FEEL FOR THE SITN IS THAT WE
JUST AREN/T CLOSE ENOUGH TO TRY AND RIDE THE ADVISORY UNTIL
MIDNIGHT. SO WL DROP IT FOR ALL BUT THE DOOR.
CAA ALOFT ARRIVING ALOFT OVER THE UNFROZEN NRN BAY WL DEEPEN THE
MIXING OVER THE DOOR...SO SHOULD STILL GET SOME INCR IN WINDS
THERE. WL MAINTAIN THE ADVISORY FOR DOOR COUNTY.
UPDATED PRODUCT SUITE WL BE OUT ASAP.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 514 PM CST SUN JAN 1 2012...
SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING TO THE NORTHEAST OVER LAKE HURON THIS AFTERNOON WHILE HIGH
PRESSURE HAS SETTLED OVER THE FRONT RANGE OF THE ROCKIES. STRONG
SHORTWAVE OVER SOUTHERN WISCONSIN IS CONTRIBUTING TO WIDESPREAD SNOW
SHOWERS AND FLURRIES ACROSS THE REGION...BUT THE SNOW SHOWERS EXIST
ALL THE WAY BACK TO NORTHERN MINNESOTA AND SW ONTARIO. LAKE EFFECT
SNOWS REMAIN NORTH OF THE U.P. BORDER SO FAR...BUT WITH SOME
IMPRESSIVE BANDS ON THE MQT RADAR. MEANWHILE...WIND GUSTS THIS
AFTERNOON HAVE REMAINED WELL BELOW ADVISORY CRITERIA SO FAR. HAVE
HAD A FEW GUSTS IN THE 34-37 KT RANGE OVER CENTRAL WISCONSIN LATE
THIS MORNING...BUT HAVE SINCE DIMINISHED. HEADLINES AND SNOW
AMOUNTS REMAIN THE MAIN FORECAST CONCERN IN THE SHORT TERM.
TONIGHT...LOW PRESSURE WILL EXIT THE REGION INTO QUEBEC WHILE ARCTIC
HIGH PRESSURE MOVES EAST OVER THE GREAT PLAINS. A TIGHT PRESSURE
GRADIENT WILL REMAIN IN PLACE BETWEEN THESE TWO FEATURES WITH 0-1KM
AGL WIND SPEEDS AROUND 35 KTS. DESPITE THE COLD ADVECTION
TODAY...WIND GUSTS HAVE BEHAVED AND HAVE ONLY BRIEFLY APPROACHED
ADVISORY CRITERIA OVER CENTRAL WISCONSIN. WILL MONITOR WIND GUSTS
UNTIL THE LAST MINUTE BEFORE MAKING HEADLINE DECISIONS ON THE WIND
ADVISORY. AFTER COORDINATION...WILL LEAVE WIND HEADLINES IN PLACE
AS A TIGHT PRESSURE GRADIENT UPSTREAM AND COLD ADVECTION CONTINUES.
STILL PLENTY GOING ON BESIDES THE GUSTY WINDS. SHORTWAVE TROUGH
NEAR MSN WILL BE EXITING OVER SOUTHERN LAKE MICHIGAN DURING THE
EVENING. ANOTHER SHEARED WAVE OVER LAKE WINNIPEG WILL DIVE
SOUTHEAST OVER THE NORTHERN MISSISSIPPI VALLEY TONIGHT AND KEEP WEAK
QG FORCING IN PLACE. COMBINED WITH 1-3SM SNOW OBS ALL THE WAY NORTH
OF INTERNATIONAL FALLS AND SATURATION OF THE COLUMN ABOVE THE -10C
LINE IN PROGGED SOUNDINGS...WILL LEAVE A SCATTERED SNOW SHOWER
MENTION ACROSS THE FORECAST AREA FOR THE DURATION OF THE EVENING.
THE BIGGEST IMPACT WILL BE THE LAKE EFFECT SNOW OVER NORTH-CENTRAL
WISCONSIN. CONDITIONS WILL BE IMPROVING FOR SIGNIFICANT
ACCUMULATIONS THROUGH THE NIGHT. MAY NOT BE A WHOLE LOT OF IMPACT
THIS EVENING...AS WIND DIRECTIONS OF 320-330 ARE NOT CONDUCIVE FOR
ACCUMS EXCEPT ALONG THE U.P. BORDER. BUT TRAJECTORIES WILL VEER
SLIGHTLY TO 340 DEGREES BY 12Z MONDAY. WITH DELTA T/S IN THE UPPER
TEENS AND 850-700MB MOISTURE OF 80 PCT...SHOULD SEE GOOD DENDRITIC
SNOW GROWTH TO GENERATE A HALF INCH TO ONE INCH PER HOUR SNOWFALL
RATES BY THIS TIME. WILL LOWER SNOW AMOUNTS IN THE EVENING...BUT
KEEP THEM AROUND 2-3 INCHES DURING THE OVERNIGHT PERIOD. THIS WILL
YIELD 3-5 INCH AMOUNTS...HIGHEST OVER THE NORTHERN PART OF VILAS
COUNTY.
MONDAY...THE LAKE EFFECT SHOW WILL CONTINUE OVER N-C WISCONSIN
DURING THE MORNING. BUT CONDITIONS WILL TURN INCREASINGLY HOSTILE
DURING THE 15-18Z TIMEFRAME AS DRY ARCTIC AIR FLOWS OVER WESTERN
LAKE SUPERIOR. AS A RESULT...SNOWFALL RATES SHOULD BE DIMINISHING
BY MIDDAY AND THROUGH THE AFTERNOON...AS THE DRY AIR SURGES
SOUTHEAST. WILL GO WITH AN ADDITIONAL 2-4 INCHES IN THE FORECAST.
CLOUDY TO MOSTLY CLOUDY CONDITIONS WILL EXIST ELSEWHERE. LEFT AN
ISOLATED FLURRY MENTION GOING FOR THE MORNING BEFORE THE DRIER AIR
ARRIVES. SOME BREAKS IN THE CLOUDS ARE LIKELY MID TO LATE
AFTERNOON. HIGHS RANGING FROM THE LOWER TEENS TO LOWER 20S.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
SURFACE RIDGE WILL GRADUALLY DRIFT INTO THE FORECAST AREA MONDAY
NIGHT. SUBSTANTIAL DRYING AND STRONG SUBSIDENCE SHOULD PRETTY
MUCH PUT AN END TO ANY LAKE EFFECT SNOW FOR VILAS COUNTY BY EARLY
MONDAY EVENING. JUST KEPT A FEW LINGERING FLURRIES FOR FAR
NORTHERN VILAS BEFORE 06Z THEN DRY THERAFTER. STILL APPEARS MONDAY
NIGHT WILL BE THE COLDEST NIGHT WE HAVE SEEN THIS SEASON WITH MIN
TEMPS EASILY FALLING INTO THE MIDDLE NEGATIVE TEENS ACROSS
NORTHCENTRAL OVERNIGHT GIVEN FRESH SNOW COVER THAT WAS RECEIEIVED EARLY
SUNDAY.
SHORTWAVE DISTURBANCE THEN QUICKLY DIVES SOUTHEAST INTO THE
WESTERN GREAT LAKES BY 00Z WEDNESDAY. AFTER A SUNNY AND COLD
START...WARM ADVECTION AHEAD OF THIS SYSTEM WILL LIKELY BRING IN
SOME MID TO HIGH-LEVEL CLOUDS DURING THE DAY ON TUESDAY. GIVEN THE
COLD START AND INCREASING CLOUDS LATER IN THE DAY...MAX TEMPS WILL
LIKELY NOT BE ABLE RISE MUCH PAST THE MIDDLE TEENS. AS PER
PREVIOUS FORECAST...STILL APPEARS LOW CHANCE POPS ARE WARRANTED
FOR FOR AT LEAST THE NORTHERN HALF OF THE FORECAST AREA. APPEARS
SYSTEM MAY BE A BIT FASTER THAN PREVIOUS MODEL RUNS THUS FOCUSED
HIGHEST POPS IN THE 00Z TO 06Z TIME FRAME. PRECIP AMOUNTS APPEAR
MINIMAL WITH LIGHT SNOW OR SNOW SHOWERS PROVIDING LITTLE IF ANY
ACCUMULATION OVERNIGHT.
DURING THE LATER HALF OF THE WORK WEEK BROAD RIDGE OVER THE
WESTERN CONUS GRADUALLY FLATTENS AND BECOMES MORE ZONAL AS SEVERAL
PIECES OF ENERGY MOVE ONSHORE OVER THE WEST COAST OF THE U.S. THIS
SHOULD LEAD TO A GENERAL BENIGN PERIOD WITH TEMPERATURES AT OR
ABOVE NORMAL STARTING WEDNESDAY...AND MODERATING FURTHER TO NEAR
40 BY WEEKS END. FAIRLY LARGE DESCREPANCY IN THE MEDIUM RANGE
MODELS FOR FRIDAY INTO THE WEEKEND ON SYSTEM MOVING ACROSS
SOUTHERN CANADA. PREFER MUCH WEAKER AND MORE ZONAL-LOOKING
ECMWF/CANADIAN. THUS KEPT FORECAST MAINLY DRY AND LEANED SLIGHTLY
WARMER THAN MODEL BLEND ESPECIALLY FOR SATURDAY.
&&
.AVIATION...LITTLE CHG IN CONDITIONS EXPECTED TNGT AS SCT SW-/SW--
CONT ACRS THE AREA.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST MONDAY FOR WIZ022.
WINTER STORM WARNING UNTIL 3 PM CST MONDAY FOR WIZ005.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
532 PM CST SUN JAN 1 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
304 PM CST SUN JAN 1 2012
MAIN FORECAST CONCERNS ARE WINDS THIS EVENING AND PRECIPITATION
CHANCES TONIGHT AS WELL AS TUESDAY EVENING.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO SOUTHWEST CANADA...AND
TROUGHING FROM HUDSON BAY SOUTH INTO THE OHIO VALLEY. WITHIN THIS
TROUGH...THE MOST IMPORTANT SHORTWAVES/PV ANOMALIES OF NOTE INCLUDE
ONE OVER SOUTHERN WISCONSIN AND THE OTHER IN SOUTHERN MANITOBA.
NEITHER OF THESE FEATURES ARE PROVIDING MUCH LIFT...NOTED BY
850-700MB AND 500-300MB QG PLOTS. HOWEVER...THEY ARE HELPING TO
LOWER THE TROPOPAUSE AND STEEPEN UP THE LOW TO MID LEVEL LAPSE
RATES. THE LAPSE RATES ARE NOTED BY HAVING 850MB TEMPS AROUND -11C
AT MPX...INL AND BIS...WHICH ARE ADVECTING SOUTHEAST ON 40-60 KT
WINDS PER 12Z RAOBS. WITH STILL PLENTY OF MOISTURE LINGERING IN THE
WAKE OF LAST NIGHTS SYSTEM AND SURFACE TEMPERATURES IN THE MID TO
UPPER 20S F...SCATTERED TO NUMEROUS SNOW SHOWERS COVER MUCH OF
WISCONSIN AND MINNESOTA. THE STEEP LAPSE RATES AND A TIGHT SURFACE
PRESSURE GRADIENT OVER THE FORECAST AREA IS ALSO LEADING TO WINDY
CONDITIONS. FOR THE MOST PART...WIND GUSTS HAVE STAYED BETWEEN 35
AND 50 MPH...STRONGEST SOUTH OF I-90 WHERE SOME SUN OCCURRED
EARLIER TODAY. FOR LOOKING AHEAD TO WHEN SKIES MIGHT CLEAR...BACK
EDGE OF THE STRATUS IS OVER THE FAR EASTERN DAKOTAS...WELL EAST OF
A 1039MB SURFACE HIGH LOCATED OVER EASTERN MONTANA.
TONIGHT AND MONDAY...SHORTWAVE/PV ANOMALY OVER SOUTHERN MANITOBA IS
FORECAST TO DROP SOUTHEAST INTO THE FORECAST AREA AFTER MIDNIGHT
TONIGHT. AGAIN...THIS FEATURE DOES NOT LOOK LIKE IT WILL PROVIDE
MUCH LIFT. HOWEVER...COLDER AIR ASSOCIATED WITH IT...NOTED BY 850MB
TEMPS FALLING TO -16 TO -18C BY 12Z MONDAY...SHOULD HELP TO KEEP THE
LOW LEVEL LAPSE RATES STEEP AND PROVIDE THE OPPORTUNITY FOR AT LEAST
SOME FLURRIES OUT OF THE STRATUS. SINCE THE LAPSE RATES REMAIN STEEP
AND THE PRESSURE GRADIENT REALLY DOES NOT RELAX THAT MUCH FROM
TODAY...EXPECTING GUSTS TO AT LEAST STAY UP IN WIND ADVISORY
CRITERIA THIS EVENING. LOSS OF DAYTIME HEATING MAY HINDER SOME OF
THE DOWNWARD TRANSPORT OF WINDS...SO HAVE NOT EXTENDED THE HAZARDS
BEYOND THE 06Z END TIME. CERTAINLY THE WINDS WILL NEED TO BE
MONITORED THROUGHOUT THE EVENING FOR POSSIBLE EXTENSION OF GOING
HAZARDS. WITH THE COLD ADVECTION...LOOK FOR TEMPERATURES TO CONTINUE
TO FALL THROUGH THE NIGHT...BOTTOMING OUT MOSTLY IN THE TEENS. 500MB
HEIGHT RISES ARE THEN PROGGED FOR MONDAY...ON THE ORDER OF 100-200
METERS BETWEEN 12-00Z...AS THE NORTHERN PART OF THE WESTERN NORTH
AMERICA RIDGING GETS PUSHED EAST. WITH SUCH STRONG SUBSIDENCE
ALOFT...NOT ANTICIPATING MUCH PRECIPITATION. IN FACT...WE SHOULD SEE
CLEARING OF THE STRATUS AS THE HIGH PRESSURE AREA IN EASTERN MONTANA
SHIFTS EAST INTO WESTERN MINNESOTA...BRINGING THE DRY AIR FROM
CANADA WITH AND AHEAD OF IT. 850MB TEMPS DO NOT WARM UP MUCH DURING
THE DAY MONDAY...ONLY TO -14 TO -16C. THEREFORE...MONDAY WILL LIKELY
BE THE COLDEST DAY WE HAVE SEEN IN AWHILE...AND ABOUT 5 DEGREES OR
SO BELOW NORMAL. A BLEND OF GUIDANCE SEEMS REASONABLE AT THIS TIME.
MONDAY NIGHT THROUGH WEDNESDAY...A SHORTWAVE TROUGH...CURRENTLY
SITTING OVER THE EAST PACIFIC...IS PROGGED TO MOVE INTO THE NORTHERN
PLAINS TUESDAY MORNING. THE TROUGH IS THEN WELL AGREED UPON TO DROP
SOUTHEAST ACROSS WISCONSIN TUESDAY EVENING...REPLACING THE BRIEF
PERIOD OF RIDGING THAT WILL HAVE BEEN IN PLACE OVER THE FORECAST
AREA ON TUESDAY. ALTHOUGH DPVA FORCING OCCURS ACROSS THE ENTIRE AREA
LATE TUESDAY INTO TUESDAY EVENING WITH THE SHORTWAVE TROUGH...MUCH
OF THE MOISTURE AND ISENTROPIC LIFT FORCING LOOKS TO STAY NORTH OF
THE FORECAST AREA. HAVE MAINTAINED SOME 20 PERCENT CHANCES FOR
TUESDAY EVENING ALONG AND NORTHEAST OF I-94...SINCE THERE IS SOME
WEAK ISENTROPIC LIFT IN THIS AREA THEN. OTHERWISE...THE ENTIRE TIME
PERIOD IS DOMINATED MOSTLY BY SUBSIDENCE...YIELDING DRY CONDITIONS.
THIS LEAVES CLOUD COVER AND TEMPERATURES THE ONLY CONCERNS. LEFTOVER
STRATUS FROM MONDAY SHOULD QUICKLY CLEAR IN THE EVENING AS THE
SURFACE HIGH MOVES IN. THIS SETS THE STAGE FOR A CHILLY NIGHT...
ESPECIALLY ACROSS WISCONSIN WHERE SNOWPACK EXISTS. BELOW ZERO
READINGS ARE LIKELY THERE. MID AND HIGH CLOUDS WILL THEN BE ON THE
INCREASE FOR TUESDAY AHEAD OF THE APPROACHING SHORTWAVE TROUGH. LOOK
FOR THESE TO CLEAR AFTER MIDNIGHT TUESDAY NIGHT...WITH A BRIEF
PERIOD OF POSSIBLE LOW STRATUS MOVING ACROSS WISCONSIN IN THE COLD
ADVECTION. THIS LOWER STRATUS LOOKS TO CLEAR WEDNESDAY
MORNING...WITH ONLY SOME HIGH CLOUDS POSSIBLE THEREAFTER. A GRADUAL
WARMING TREND IN TEMPERATURES IS FORECAST FOR TUESDAY AND
WEDNESDAY...RESULTING FROM 850MB TEMPS CLIMBING TO -4 TO -8C BY 00Z
WEDNESDAY AND 0 TO -4C BY 00Z THURSDAY. CERTAINLY SNOW FREE AREAS
SUCH AS NORTHEAST IOWA WILL HAVE AN EASIER TIME WARMING UP...WHICH
ALSO HAPPENS TO BE WHERE THE WARMEST 850MB AIR IS PROGGED. A BLEND
OF GUIDANCE STILL LOOKS REASONABLE FOR TEMPERATURES.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
304 PM CST SUN JAN 1 2012
01.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ARE GENERALLY IN GOOD
AGREEMENT THROUGH THE ENTIRE LONG TERM PERIOD. UPPER RIDGING THAT
HAS BEEN PRESENT OVER THE WESTERN U.S. IS STILL SHOWN TO FLATTEN OUT
AND PUSH EAST...IN RESPONSE TO A FAIRLY POTENT TROUGH COMING INTO
SOUTHWEST CANADA AROUND 00Z FRIDAY. THIS UPPER RIDGING WILL BRING
WITH IT 850MB TEMPS THAT ARE AROUND 2 STANDARD DEVIATIONS ABOVE
NORMAL INTO THE FORECAST AREA FRIDAY MORNING. THE SURFACE WARM FRONT
LEADING THE WARMER AIR LOOKS TO MOVE THROUGH THE AREA THURSDAY
NIGHT. MAY SEE SOME MID AND HIGH CLOUDS AHEAD OF THE WARM FRONT FOR
WEDNESDAY NIGHT AND THURSDAY...BUT NO PRECIPITATION IS ANTICIPATED
DUE TO PLENTY OF LOW LEVEL DRY AIR. COLD FRONT MOVES THROUGH DURING
THE DAY FRIDAY WITH LITTLE FANFARE. THE FRONT WILL BRING IN SOME
COOLER AIR...KNOCKING 850MB TEMPS DOWN FROM THE 8-10C READINGS AT
12Z FRIDAY TO PERHAPS AS COOL AS 2-6C BY 00Z SATURDAY. HOWEVER...THE
FRONT MAY ACTUALLY HELP TO PRODUCE BETTER MIXING. WITH MOSTLY SUNNY
SKIES ANTICIPATED ON FRIDAY...READINGS IN THE 40S ARE LIKELY WITH
50S CERTAINLY NOT OUT OF THE QUESTION. COLDEST READINGS EXPECTED
OVER NORTH CENTRAL WISCONSIN...WHILE WARMEST READINGS WOULD OCCUR
OVER NORTHEAST IOWA.
FOR NEXT WEEKEND...BROAD TROUGHING DEVELOPS FROM THE SOUTHWESTERN
U.S. INTO ONTARIO...WITH SOME INDICATIONS THAT IT MAY SPLIT INTO TWO
PIECES. MUCH OF THIS TROUGHING FORMS FROM THAT POTENT TROUGH...WHICH
IS DIGGING INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA ON
FRIDAY. THIS TROUGHING COMING INTO THE FORECAST AREA WILL ALLOW FOR
COLDER AIR TO MOVE INTO THE AREA. 850MB TEMPS ARE PROGGED TO DROP TO
-6 TO -10C BY 00Z SUNDAY AND AT LEAST -10 TO -14C BY 00Z MONDAY.
NOTE...THE 01.12Z ECMWF NOW SHOWS WARMER CONDITIONS...WITH 850MB
TEMPS ONLY DROPPING TO 0 TO -3C BY 00Z SUNDAY AND -4 TO -8C BY 00Z
MONDAY. THEREFORE...IT IS POSSIBLE THAT THE WEEKEND MIGHT BE A
LITTLE WARMER THAN FORECAST. DESPITE THE COOLING...NOT A LOT OF
MOISTURE LOOKS TO ACCOMPANYING THE TROUGH...SO DRY CONDITIONS ARE
FORECAST AT THIS TIME.
&&
.AVIATION...TONIGHT AND MONDAY
532 PM CST SUN JAN 1 2012
BIGGEST CONCERN CONTINUES TO BE ON THE HIGH WINDS. STRONG PRESSURE
GRADIENT WILL CONTINUE IN PLACE THROUGH MUCH OF THE PERIOD. A SLOW
DECREASE IN THE WINDS IS EXPECTED TONIGHT...BUT STILL GUSTING TO
NEAR 30 KNOTS AFTER 06Z TONIGHT. THE GRADIENT DOES RELAX A LITTLE
AFTER 21Z MONDAY AS HIGH PRESSURE BEGINS TO BUILD TOWARDS THE
REGION FROM THE PLAINS.
THE SECOND CONCERN IS ON CEILING HEIGHTS AND WHEN STRATUS CLEARS
THE TAF SITES. MODELS AND SURFACE REPORTS UPSTREAM WOULD SUGGEST
CEILINGS RISING INTO THE VFR CATEGORY THIS EVENING AT BOTH TAF
SITES. STILL SOME UNCERTAINTY WITH CLEARING TREND WITH MODELS
SHOWING CLOUDS TO SCATTER OUT 12Z-15Z AT KRST AND NOT TIL 19Z-21Z
AT KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
304 PM CST SUN JAN 1 2012
WI...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ017-029-032>034-
041>044-053>055-061.
MN...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ079-086>088-
094>096.
IA...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
514 PM CST SUN JAN 1 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING TO THE NORTHEAST OVER LAKE HURON THIS AFTERNOON WHILE HIGH
PRESSURE HAS SETTLED OVER THE FRONT RANGE OF THE ROCKIES. STRONG
SHORTWAVE OVER SOUTHERN WISCONSIN IS CONTRIBUTING TO WIDESPREAD SNOW
SHOWERS AND FLURRIES ACROSS THE REGION...BUT THE SNOW SHOWERS EXIST
ALL THE WAY BACK TO NORTHERN MINNESOTA AND SW ONTARIO. LAKE EFFECT
SNOWS REMAIN NORTH OF THE U.P. BORDER SO FAR...BUT WITH SOME
IMPRESSIVE BANDS ON THE MQT RADAR. MEANWHILE...WIND GUSTS THIS
AFTERNOON HAVE REMAINED WELL BELOW ADVISORY CRITERIA SO FAR. HAVE
HAD A FEW GUSTS IN THE 34-37 KT RANGE OVER CENTRAL WISCONSIN LATE
THIS MORNING...BUT HAVE SINCE DIMINISHED. HEADLINES AND SNOW
AMOUNTS REMAIN THE MAIN FORECAST CONCERN IN THE SHORT TERM.
TONIGHT...LOW PRESSURE WILL EXIT THE REGION INTO QUEBEC WHILE ARCTIC
HIGH PRESSURE MOVES EAST OVER THE GREAT PLAINS. A TIGHT PRESSURE
GRADIENT WILL REMAIN IN PLACE BETWEEN THESE TWO FEATURES WITH 0-1KM
AGL WIND SPEEDS AROUND 35 KTS. DESPITE THE COLD ADVECTION
TODAY...WIND GUSTS HAVE BEHAVED AND HAVE ONLY BRIEFLY APPROACHED
ADVISORY CRITERIA OVER CENTRAL WISCONSIN. WILL MONITOR WIND GUSTS
UNTIL THE LAST MINUTE BEFORE MAKING HEADLINE DECISIONS ON THE WIND
ADVISORY. AFTER COORDINATION...WILL LEAVE WIND HEADLINES IN PLACE
AS A TIGHT PRESSURE GRADIENT UPSTREAM AND COLD ADVECTION CONTINUES.
STILL PLENTY GOING ON BESIDES THE GUSTY WINDS. SHORTWAVE TROUGH
NEAR MSN WILL BE EXITING OVER SOUTHERN LAKE MICHIGAN DURING THE
EVENING. ANOTHER SHEARED WAVE OVER LAKE WINNIPEG WILL DIVE
SOUTHEAST OVER THE NORTHERN MISSISSIPPI VALLEY TONIGHT AND KEEP WEAK
QG FORCING IN PLACE. COMBINED WITH 1-3SM SNOW OBS ALL THE WAY NORTH
OF INTERNATIONAL FALLS AND SATURATION OF THE COLUMN ABOVE THE -10C
LINE IN PROGGED SOUNDINGS...WILL LEAVE A SCATTERED SNOW SHOWER
MENTION ACROSS THE FORECAST AREA FOR THE DURATION OF THE EVENING.
THE BIGGEST IMPACT WILL BE THE LAKE EFFECT SNOW OVER NORTH-CENTRAL
WISCONSIN. CONDITIONS WILL BE IMPROVING FOR SIGNIFICANT
ACCUMULATIONS THROUGH THE NIGHT. MAY NOT BE A WHOLE LOT OF IMPACT
THIS EVENING...AS WIND DIRECTIONS OF 320-330 ARE NOT CONDUCIVE FOR
ACCUMS EXCEPT ALONG THE U.P. BORDER. BUT TRAJECTORIES WILL VEER
SLIGHTLY TO 340 DEGREES BY 12Z MONDAY. WITH DELTA T/S IN THE UPPER
TEENS AND 850-700MB MOISTURE OF 80 PCT...SHOULD SEE GOOD DENDRITIC
SNOW GROWTH TO GENERATE A HALF INCH TO ONE INCH PER HOUR SNOWFALL
RATES BY THIS TIME. WILL LOWER SNOW AMOUNTS IN THE EVENING...BUT
KEEP THEM AROUND 2-3 INCHES DURING THE OVERNIGHT PERIOD. THIS WILL
YIELD 3-5 INCH AMOUNTS...HIGHEST OVER THE NORTHERN PART OF VILAS
COUNTY.
MONDAY...THE LAKE EFFECT SHOW WILL CONTINUE OVER N-C WISCONSIN
DURING THE MORNING. BUT CONDITIONS WILL TURN INCREASINGLY HOSTILE
DURING THE 15-18Z TIMEFRAME AS DRY ARCTIC AIR FLOWS OVER WESTERN
LAKE SUPERIOR. AS A RESULT...SNOWFALL RATES SHOULD BE DIMINISHING
BY MIDDAY AND THROUGH THE AFTERNOON...AS THE DRY AIR SURGES
SOUTHEAST. WILL GO WITH AN ADDITIONAL 2-4 INCHES IN THE FORECAST.
CLOUDY TO MOSTLY CLOUDY CONDITIONS WILL EXIST ELSEWHERE. LEFT AN
ISOLATED FLURRY MENTION GOING FOR THE MORNING BEFORE THE DRIER AIR
ARRIVES. SOME BREAKS IN THE CLOUDS ARE LIKELY MID TO LATE
AFTERNOON. HIGHS RANGING FROM THE LOWER TEENS TO LOWER 20S.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
SURFACE RIDGE WILL GRADUALLY DRIFT INTO THE FORECAST AREA MONDAY
NIGHT. SUBSTANTIAL DRYING AND STRONG SUBSIDENCE SHOULD PRETTY
MUCH PUT AN END TO ANY LAKE EFFECT SNOW FOR VILAS COUNTY BY EARLY
MONDAY EVENING. JUST KEPT A FEW LINGERING FLURRIES FOR FAR
NORTHERN VILAS BEFORE 06Z THEN DRY THERAFTER. STILL APPEARS MONDAY
NIGHT WILL BE THE COLDEST NIGHT WE HAVE SEEN THIS SEASON WITH MIN
TEMPS EASILY FALLING INTO THE MIDDLE NEGATIVE TEENS ACROSS
NORTHCENTRAL OVERNIGHT GIVEN FRESH SNOW COVER THAT WAS RECEIEIVED EARLY
SUNDAY.
SHORTWAVE DISTURBANCE THEN QUICKLY DIVES SOUTHEAST INTO THE
WESTERN GREAT LAKES BY 00Z WEDNESDAY. AFTER A SUNNY AND COLD
START...WARM ADVECTION AHEAD OF THIS SYSTEM WILL LIKELY BRING IN
SOME MID TO HIGH-LEVEL CLOUDS DURING THE DAY ON TUESDAY. GIVEN THE
COLD START AND INCREASING CLOUDS LATER IN THE DAY...MAX TEMPS WILL
LIKELY NOT BE ABLE RISE MUCH PAST THE MIDDLE TEENS. AS PER
PREVIOUS FORECAST...STILL APPEARS LOW CHANCE POPS ARE WARRANTED
FOR FOR AT LEAST THE NORTHERN HALF OF THE FORECAST AREA. APPEARS
SYSTEM MAY BE A BIT FASTER THAN PREVIOUS MODEL RUNS THUS FOCUSED
HIGHEST POPS IN THE 00Z TO 06Z TIME FRAME. PRECIP AMOUNTS APPEAR
MINIMAL WITH LIGHT SNOW OR SNOW SHOWERS PROVIDING LITTLE IF ANY
ACCUMULATION OVERNIGHT.
DURING THE LATER HALF OF THE WORK WEEK BROAD RIDGE OVER THE
WESTERN CONUS GRADUALLY FLATTENS AND BECOMES MORE ZONAL AS SEVERAL
PIECES OF ENERGY MOVE ONSHORE OVER THE WEST COAST OF THE U.S. THIS
SHOULD LEAD TO A GENERAL BENIGN PERIOD WITH TEMPERATURES AT OR
ABOVE NORMAL STARTING WEDNESDAY...AND MODERATING FURTHER TO NEAR
40 BY WEEKS END. FAIRLY LARGE DESCREPANCY IN THE MEDIUM RANGE
MODELS FOR FRIDAY INTO THE WEEKEND ON SYSTEM MOVING ACROSS
SOUTHERN CANADA. PREFER MUCH WEAKER AND MORE ZONAL-LOOKING
ECMWF/CANADIAN. THUS KEPT FORECAST MAINLY DRY AND LEANED SLIGHTLY
WARMER THAN MODEL BLEND ESPECIALLY FOR SATURDAY.
&&
.AVIATION...LITTLE CHG IN CONDITIONS EXPECTED TNGT AS SCT SW-/SW--
CONT ACRS THE AREA.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ010>013-018>021-
030-031-035>040-045-048>050-073-074.
WIND ADVISORY UNTIL 6 PM CST MONDAY FOR WIZ022.
WINTER STORM WARNING UNTIL 3 PM CST MONDAY FOR WIZ005.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 PM CST SAT DEC 31 2011
.SHORT TERM...TONIGHT THROUGH TUESDAY
315 PM CST SAT DEC 31 2011
MAIN FORECAST CONCERNS ARE HIGH WIND POTENTIAL TONIGHT THROUGH
SUNDAY NIGHT AND WINTER WEATHER CONCERNS ON TOP OF THESE WINDS.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING BUILDING UP ALONG THE WEST COAST OF THE U.S. INTO
BRITISH COLUMBIA...A SPLIT TROUGH OVER THE CENTRAL PORTION OF NORTH
AMERICA...AND RIDGING OVER THE WESTERN GREAT LAKES AND OHIO VALLEY
REGIONS. WITHIN THE SPLIT TROUGH...A VERY POTENT SHORTWAVE WAS NEAR
GOODLAND KANSAS...AN UPPER LOW OVER SOUTHERN MANITOBA...AND A
SHORTWAVE ON ITS BACK SIDE IN SOUTHERN ALBERTA. MUCH FOCUS IN ON
THAT POTENT SHORTWAVE FOR THIS FORECAST. AT 12Z...WHEN IT WAS BACK
NEAR RIVERTON WYOMING...THE SOUNDING SHOWED A DROP IN THE TROPOPAUSE
OF 200MB AND A 500MB TEMP THAT COOLED 13C FROM THE PREVIOUS 00Z
SOUNDING. MODELS HAVE STRUGGLED WITH THIS SHORTWAVE WITH ALL OF THEM
NEEDING TO SHIFT MORE SOUTH AND DEEPER...ESPECIALLY THE NAM IN WHICH
ITS 30.12Z RUN FORECASTED THE SHORTWAVE TO BE IN EASTERN SOUTH
DAKOTA AT THIS TIME. AHEAD OF THE POTENT SHORTWAVE...A 995MB LOW WAS
LOCATED OVER SOUTHEAST NEBRASKA. SOUTH WINDS OF 35 TO 50 KT WERE
OCCURRING AT 925MB PER PROFILER DATA AHEAD OF THIS SURFACE
LOW...ADVECTING WARMER AIR INTO THE FORECAST AREA. TEMPERATURES HAVE
CLIMBED INTO THE 30S AND 40S...WARMEST IN NORTHEAST IOWA. ON THE
BACK SIDE OF THE SURFACE LOW ACROSS WESTERN PORTIONS OF NEBRASKA...
KANSAS AND ADJACENT STATES...SURFACE WINDS HAVE BEEN BLOWING HARD.
PEAK GUSTS OF 40-50 KT AND EVEN A FEW UP AROUND 60 KT HAVE BEEN
REPORTED. ALSO ON THE BACK SIDE OF THE LOW...PRECIPITATION HAS BEEN
FORMING OVER NEBRASKA IN THE DEFORMATION AXIS.
TONIGHT...FOCUS AGAIN IS MOSTLY ON THE POTENT SHORTWAVE. GOOD
MODEL AGREEMENT EXISTS THAT THIS SHORTWAVE LIFTS RAPIDLY NORTHEAST
INTO SOUTHERN LAKE MICHIGAN BY 12Z SUNDAY. THIS TRACK PLACES THE
BEST 500MB HEIGHT FALLS TO OUR SOUTH...HOWEVER...PLENTY OF DPVA
STILL OCCURS NORTH OF IT OVER THE FORECAST AREA. NEXT CONCERN IS THE
DEFORMATION PRECIPITATION DEVELOPING OVER NEBRASKA. VERY GOOD
AGREEMENT EXISTS THAT THIS PRECIPITATION WILL FORM INTO A
SOUTHWEST-NORTHEAST BAND FROM WESTERN IOWA INTO NORTHWEST WISCONSIN
THIS EVENING. IN FACT...THE BAND SHOULD INTENSIFY AS AN UPPER JET
STREAK DEVELOPS OVER NORTHERN MINNESOTA...PLACING THE BAND IN THE
FAVORABLE RIGHT ENTRANCE REGION. AS THIS JET CORE LIFTS INTO
NORTHERN ONTARIO LATE IN THE EVENING THROUGH THE OVERNIGHT...THE
DEFORMATION BAND OF PRECIPITATION LOOKS TO WEAKEN AS IT PUSHES EAST
INTO THE FORECAST AREA. MEANWHILE...A NEW DEFORMATION BAND AIDED BY
THE STRONGER 500MB HEIGHT FALLS IS FORECAST TO FORM FROM EASTERN
IOWA INTO NORTHEAST WISCONSIN AFTER MIDNIGHT. BOTH BANDS CERTAINLY
GIVE A GOOD OPPORTUNITY FOR PRECIPITATION...SO PRECIPITATION CHANCES
ARE AT 100. HOWEVER...HAVE HAD TO DELAY SOME OF THE PRECIPITATION
THIS EVENING BECAUSE OF THE FARTHER SOUTH TRACK WITH THE
SHORTWAVE/SURFACE LOW. SNOWFALL AMOUNTS ARE TRICKY TOO. WITH A
SLOWER MOVEMENT DUE TO THE SHORTWAVE BEING MORE AMPLIFIED...THE
PRECIPITATION MAY END UP AS RAIN OR RAIN/SNOW MIX FOR A COUPLE
HOURS. ONCE THE COLD AIR COMES IN...THERE MAY BE AN HOUR OF SOME
HEAVIER SNOW...BUT THEN THE DEFORMATION BANDS PUSH EAST. COMBINE
THAT WITH THE FACT THAT SNOW TO WATER RATIOS MAY ONLY END UP 10-15
TO 1...KEPT DOWN TOO AS A RESULT OF STRONGER WINDS DEVELOPING
BREAKING THE SNOW CRYSTALS APART. HAVE REDUCED SNOWFALL AMOUNTS SOME
TONIGHT...WITH NOW ONLY LESS THAN AN INCH SOUTH OF I-90 TO 1-2
INCHES ALONG AND NORTH OF THERE. NEXT CONCERN IS THE WINDS. AS THE
SURFACE LOW ASSOCIATED WITH THE SHORTWAVE LIFTS INTO SOUTHEAST
WISCONSIN AFTER MIDNIGHT...WINDS SHOULD KICK UP DRAMATICALLY IN ITS
WAKE. A TIGHT PRESSURE GRADIENT...COLD AIR ADVECTION FOR MIXING...
SUBSIDENCE AND RAPID PRESSURE RISES ARE ALL PRESENT...WHICH SHOULD
ALLOW WINDS TO CRANK UP. WITH A 50-60KT CORE OF WINDS FORECAST
BETWEEN 900-850MB...MUCH OF THIS SHOULD MIX DOWN. GREATEST POTENTIAL
TO SEE HIGH WIND WARNING IS OVER NORTHEAST IOWA WHERE ISALLOBARIC
FORCING IS MAXIMIZED. HAVE ISSUED THE WARNING IN THIS AREA. THE
COMBINATION OF THE WINDS AND SNOW WILL RESULT IN SOME BLOWING
SNOW...BUT THE EXTENT IS UNCERTAIN DUE TO AMOUNT OF SNOWFALL AND A
WARMER GROUND FROM THE EVENING HOURS. BECAUSE OF THIS...DID NOT
UPGRADE ANY WINTER WEATHER ADVISORIES TO WARNINGS.
SUNDAY INTO SUNDAY NIGHT...POTENT SHORTWAVE IS PROGGED TO LIFT
QUICKLY AWAY FROM THE AREA...WHILE THE SHORTWAVE OVER ALBERTA IS
FORECAST TO SLIDE ACROSS WESTERN PORTIONS OF THE FORECAST AREA
DURING THE DAY SUNDAY. INTERESTING FACT WITH THIS NEXT SHORTWAVE IS
THAT THE TROPOPAUSE DROPS TO 600MB OR SO. WITH THIS SHORTWAVE COMING
THROUGH...ALONG WITH THE SURFACE PRESSURE GRADIENT REMAINING TIGHT
AND DURING PEAK HEATING...FELT IT WAS PRUDENT TO KEEP THE HIGH WIND
WARNING GOING RIGHT THROUGH SUNDAY. ELSEWHERE...WIND ADVISORIES ARE
STILL APPROPRIATE...AND KEPT THE WINTER WEATHER ADVISORY GOING FOR
EASTERN PORTIONS OF THE FORECAST AREA UNTIL 15Z TO HANDLE ANY
LINGERING DEFORMATION PRECIPITATION AS WELL AS BLOWING SNOW. BLOWING
SNOW IS POSSIBLE ELSEWHERE...ESPECIALLY IN THE MORNING BEFORE SNOW
PROBABLY BECOMES COMPACTED ENOUGH TO NOT RESTRICT VISIBILITIES AS
MUCH. DID ALSO MAINTAIN 20-30 PERCENT CHANCES THROUGHOUT THE DAY
SUNDAY FOR ISOLATED-SCATTERED SNOW SHOWERS...PRODUCED BY WEAK LIFT
INDICATED IN THE LEFT-OVER STRATUS DECK BEHIND THE SYSTEM. DECIDED
TOO TO HAVE A MENTION OF FLURRIES SUNDAY NIGHT WITH THE STRATUS DECK
STILL AROUND...AS WELL AS NEUTRAL TO VERY WEAK LIFT IN THE CLOUDS.
NOTE THAT MUCH OF SUNDAY NIGHT SHOULD END UP IN SUBSIDENCE WITH THE
GENERAL UPPER TROUGH HEADING EAST. WITH COLD ADVECTION OCCURRING
THROUGHOUT SUNDAY AND SUNDAY NIGHT...TEMPERATURES LOOK TO PRETTY
MUCH HOLD STEADY OR SLIGHTLY FALL ON SUNDAY...FOLLOWED BY DROPPING
INTO THE TEENS AND POSSIBLY SINGLE DIGITS FOR NORTH CENTRAL
WISCONSIN. WINDS LOOK TO DIMINISH BELOW ADVISORY CRITERIA AROUND THE
CURRENT END TIME IN THE FORECAST...06Z MONDAY...THOUGH IT IS
POSSIBLE IT MAY NEED EXTENSION TO 12Z. WILL LET LATER SHIFTS TACKLE
THIS MORE.
MONDAY INTO MONDAY NIGHT...500MB HEIGHTS ARE FORECAST TO RISE QUITE
A BIT DURING THIS TIME PERIOD...IN RESPONSE TO UPPER RIDGING BEING
PUSHED EASTWARD INTO THE PLAINS. SUBSIDENCE ASSOCIATED WITH THE
BUILDING HEIGHTS SHOULD RESULT IN A DRY FORECAST WITH GRADUAL
CLEARING OF CLOUDS. WINDS LOOK TO ALSO GRADUAL DIMINISH...LIKELY
GOING TO CALM MONDAY NIGHT WHEN THE SURFACE RIDGE MOVES THROUGH.
DESPITE THE CLEARING OF CLOUDS...ANTICIPATING TEMPERATURES TO STILL
STRUGGLE TO RISE MUCH...GIVEN 850MB TEMPS FORECAST BETWEEN -14 TO
-18C MUCH OF THE DAY. GENERALLY FOLLOWED A BLEND OF GUIDANCE FOR
HIGHS. COULD SEE SOME BELOW ZERO TEMPERATURES MONDAY NIGHT...
ESPECIALLY IN THE TYPICAL COLD SPOTS OF WISCONSIN WITH SNOW LIKELY
ON THE GROUND...COMBINED WITH THE CLEARING SKIES AND DIMINISHING
WIND. IF THINGS SPEED UP A LITTLE MORE THAN WHAT IS FORECAST...A
RISING TEMPERATURE TREND MAY NEED TO BE INCLUDED OVER WESTERN
PORTIONS OF THE FORECAST AREA MONDAY NIGHT.
TUESDAY...THE FEATURE MODELS HAVE PUSHING THE UPPER RIDGE EASTWARD
INTO THE PLAINS IS A SHORTWAVE TROUGH...FORECAST OVER FAR EASTERN
MONTANA AT 12Z TUESDAY. THIS TROUGH WILL HEAD EAST INTO MINNESOTA BY
00Z WEDNESDAY...INITIATING A WARM ADVECTION PATTERN OVER THE
FORECAST AREA. AS A RESULT OF THIS WARM ADVECTION...LIKELY TO SEE
DEVELOPMENT/TRANSLATION OF MID AND HIGH CLOUDS INTO THE FORECAST
AREA. RAISED SKY COVER SOME...BUT MORE INCREASES MAY BE NECESSARY.
PRECIPITATION IS NOT EXPECTED DUE TO DRIER LOW LEVEL AIR AND MUCH OF
THE DPVA/THERMODYNAMIC FORCING PROGGED NORTHWEST OF THE FORECAST
AREA. CERTAINLY SOMETHING TO WATCH. 850MB TEMPS DO CLIMB UP TO -4 TO
-8C BY 00Z...SO HIGH TEMPERATURES SHOULD GET BACK UP INTO THE 20S
FOR MOST LOCATIONS.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
315 PM CST SAT DEC 31 2011
31.12 MODELS SHOWING A SHORTWAVE TROUGH MOVING ACROSS NORTHERN
MINNESOTA AND INTO CENTRAL WISCONSIN TUESDAY NIGHT. THIS TROUGH HAS
BEEN A FAIRLY CONSISTENT SIGNAL IN THE MODELS SO HAVE DECIDED TO
EXPAND PRECIPITATION CHANCES FURTHER SOUTH...MAINLY TO ALONG THE
I-94 CORRIDOR. TEMPERATURES WILL BE COLD ENOUGH TO ALLOW THE
PRECIPITATION TO FALL AS SNOW. LOOK FOR LOW TEMPERATURES TO RANGE
FROM THE MID TEENS ACROSS NORTH CENTRAL WISCONSIN TO AROUND 20
ACROSS NORTHEAST IOWA. A BROAD UPPER RIDGE IS EXPECTED TO SLIDE FROM
THE NORTHERN PLAINS AND INTO THE UPPER MISSISSIPPI RIVER VALLEY
WEDNESDAY INTO THURSDAY...WITH A GRADUAL WARMING TREND EXPECTED
ACROSS THE FORECAST AREA. 850 MB TEMPERATURES WILL START OUT AROUND
NEGATIVE 2 C EARLY WEDNESDAY AFTERNOON...WARMING TO AROUND PLUS 10 C
BY THURSDAY AFTERNOON. HAVE NUDGED TEMPERATURES TOWARDS THE ECMWF
WHICH SEEMS TO BE HANDLING TEMPERATURES BETTER OVERALL. QUIET
WEATHER IS ANTICIPATED WEDNESDAY THROUGH THURSDAY WITH HIGH PRESSURE
IN CONTROL. LOOK FOR HIGH TEMPERATURES MAINLY IN THE 30S ON
WEDNESDAY...WARMING INTO THE 40S BY THURSDAY. FRIDAY COULD BE EVEN
WARMER WITH TEMPS CLIMBING INTO THE UPPER 40S IN SOME LOCATIONS.
HAVE INCREASED HIGH A COUPLE OF DEGREES ON FRIDAY...BUT IF TRENDS
CONTINUE THEY WILL HAVE TO BE INCREASED FURTHER. THE RIDGE WILL PUSH
EAST THROUGH THE DAY ON FRIDAY AS A COLD FRONT SWINGS SOUTH FROM
CANADA AND THROUGH THE UPPER MIDWEST. THE OVERALL UPPER PATTERN
LOOKS TO TRANSITION TO A NORTHWEST FLOW SCENARIO IN THE WAKE OF THE
FRONT WITH A BROAD UPPER TROUGH SETTING UP ACROSS THE REGION. A
SHORTWAVE TROUGH IS EXPECTED TO MOVE ACROSS THE REGION ON SATURDAY
BRINGING A CHANCE OF LIGHT SNOW TO THE AREA.
&&
.AVIATION...THROUGH 18Z SUNDAY
1207 AM CST SAT DEC 31 2011
A STRONG COLD FRONT WILL PUSH ACROSS THE AREA TONIGHT BRINGING
STRONG NORTHWEST WINDS AND SNOW TO THE TAF SITES. PLAN ON IFR
CONDITIONS THROUGH MUCH OF THIS AFTERNOON AS LOW LEVEL MOISTURE
REMAINS IN PLACE. THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE
AREA LATE THIS EVENING. RAIN WILL DEVELOP FIRST...THEN SWITCHING
OVER SNOW AS COLD AIR SWEEPS INTO THE REGION. WIND WILL QUICKLY
INCREASE BEHIND THE FRONT INTO THE 25 TO 30 KT RANGE WITH GUSTS TO
AROUND 47 KTS POSSIBLE...ESPECIALLY AT KRST. A PERIOD OF LIFR
CONDITIONS ARE EXPECTED AS THE SNOW MOVES THROUGH. THE COMBINATION
OF THE WIND AND SNOW WILL REDUCED VISIBILITIES TO AROUND 1 MILE OR
POSSIBLY LESS AT TIMES. CONDITIONS WILL IMPROVE TO MVFR SUNDAY
MORNING WITH BLOWING SNOW PERSISTING. PLAN ON VISIBILITIES IN THE
4 TO 5 SM RANGE. NORTHWEST WINDS WILL REMAIN IN THE 25 TO 30 KT RANGE
WITH GUSTS UP TO 47 KTS POSSIBLE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 PM CST SAT DEC 31 2011
WI...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY
FOR WIZ041-053>055-061.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST
SUNDAY FOR WIZ032-033.
WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
WIZ032-033-041-053>055-061.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY
FOR WIZ042>044.
WIND ADVISORY FROM 9 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
WIZ017-029-034-042>044.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST
SUNDAY FOR WIZ017-029-034.
MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY
FOR MNZ096.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST
SUNDAY FOR MNZ079-086>088-094-095.
WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
MNZ079-086>088-094>096.
IA...HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY
NIGHT FOR IAZ008-018-019-029-030.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY
FOR IAZ010-011-019-029-030.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST
SUNDAY FOR IAZ008-009-018.
WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
IAZ009>011.
&&
$$
SHORT TERM...AJ
LONG TERM...WETENKAMP
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
226 PM CST SAT DEC 31 2011
.SHORT TERM...TONIGHT THROUGH NEW YEARS DAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DEVELOPING
LOW PRESSURE SYSTEM MOVING EAST OVER SOUTHEAST NEBRASKA THIS
AFTERNOON...JUST AHEAD OF A VIGOROUS SHORTWAVE. WEAK SHORTWAVE
IMPULSE TRAVELING NORTHEAST OVER MINNESOTA HAS GENERATED A BAND OF
SLEET/FREEZING RAIN OVER NORTHERN WISCONSIN WHICH HAS BEEN REACHING
THE GROUND...BUT IS NOT ACCUMULATING...ACCORDING TO A SPOTTER AT
LAKE TOMAHAWK. OTHERWISE...MID AND HIGH CLOUDS CONTINUE TO PASS
OVER THE STATE...AND LOW CLOUDS CONTINUE TO BE A NUISANCE OVER
CENTRAL AND NORTHEAST WISCONSIN...JUST NORTH OF A SURFACE WARM
FRONT. AHEAD OF THE LOW...PLENTY OF CLEAR SKIES AND DRY AIR EXISTS
OVER KANSAS...MISSOURI...AND SOUTHERN ILLINOIS WHERE DEWPOINTS ARE
IN THE 20S AND 30S. BUT FARTHER NW...AN FGEN BAND IS DEVELOPING
OVER NE NEBRASKA AND SE SOUTH DAKOTA...WHICH WILL BE THE FEATURE TO
WATCH HEADING INTO TONIGHT. ALSO...BEEFY WINDS OF 45-60 KTS ARE
IMPACTING THE FRONT RANGE OF THE ROCKIES. AS THE SURFACE LOW TRACKS
NE...HEADLINES FOR BOTH SNOW AND WIND ARE THE MAIN FORECAST CONCERNS.
TONIGHT...BEEFY SHORTWAVE OVER THE PLAINS WILL BECOME NEGATIVELY
TILTED AS IT DRIVES A SURFACE LOW TO THE NORTHEAST TO CENTRAL OR
SOUTHERN LAKE MICHIGAN. MODELS DIDNT INITIALIZE ALL THAT WELL THIS
MORNING (TOO WEAK WITH THE SHORTWAVE...AND THERMAL PROBLEMS)...SO
ITS TOUGH TO HAVE CONFIDENCE IN ANY ONE PARTICULAR MODEL. TRIED TO
BLEND THE NAM AND GFS...BUT CONFIDENCE IS NO BETTER THAN AVERAGE
WITH THE DETAILS. ALTHOUGH WILL HAVE SE WINDS AT THE
SURFACE...WINDS TURN TO THE SW ALOFT AND DRAW IN WARMER AIR FROM THE
CENTRAL PLAINS. HOWEVER...THE AIR FROM THE PLAINS IS ALSO QUITE DRY
AS DEPICTED BY THE 12Z RAOBS (PWATS LESS THAN 0.4 INCHES INTO
NORTHERN TEXAS AND LOUISIANA)...AND PRECIP MAY BE SLOW TO MOVE INTO
THE REGION DESPITE INCREASING FORCING. AS A RESULT...HAVE DELAYED
PRECIP UNTIL AFTER MIDNIGHT. AS THE LOW MOVES OVER SOUTHEAST
WISCONSIN TONIGHT...A TIGHTENING THERMAL GRADIENT ON THE NW FLANK OF
THE LOW WILL LEAD TO AN FGEN CIRCULATION MOVING FROM SW TO NE ACROSS
THE STATE. PTYPE IS LIKELY TO START OUT AS ALL SNOW OVER N-C
WISCONSIN...WHERE EVAPORATION INTO A DRY LAYER ALOFT YIELDS WET BULB
TEMPERATURES BELOW ZERO. NOT AS CLEAR CUT OVER CENTRAL WISCONSIN
WHERE WET BULB TEMPERATURES APPROACH 0C AT MIDNIGHT SO LEFT A
RAIN/SNOW MIX THERE. ENOUGH WARM AIR LOOKS TO SURGE INTO THE FOX
VALLEY AND LAKESHORE WHERE PTYPE COULD START OUT AS ALL
RAIN...BEFORE TRANSITIONING TO A MIX OR ALL SNOW BY 12Z. BECAUSE
OF THE MIX...SNOW ACCUMS LOOK TO BE QUITE A BIT HIGHER OVER CENTRAL
AND NORTH-CENTRAL WISCONSIN...ON THE ORDER OF 1 TO 3
INCHES...COMPARED TO LESS THAN AN INCH OVER THE FOX VALLEY AND LAKE
SHORE. WINDS WILL ALSO BE BEGINNING TO STRENGTHEN LATE
TONIGHT...BUT THE REAL PUSH WONT BE UNTIL SUNDAY MORNING.
NEW YEARS DAY...LOW PRESSURE WILL CONTINUE TO STRENGTHEN AS IT LIFTS
OVER NORTHERN LOWER MICHIGAN AND LAKE HURON ON SUNDAY. ONGOING
PRECIP WILL HAVE CHANGED TO ALL SNOW EXCEPT OVER DOOR COUNTY EARLY
SUNDAY MORNING. ARCTIC AIR WILL BE ROTATING AROUND THE LOW...WHICH
WILL STEEPEN LOW LEVEL LAPSE RATES...AND ALLOW MIXING OF 900MB WINDS
OF 40 TO 50 KTS. BECAUSE OF THE WINDS AND SNOWFALL...SUNDAY MORNING
LOOKS TO HAVE THE MOST IMPACT FROM THE STORM...AS THERE COULD BE A
2-3 HR PERIOD OF FAIRLY NASTY CONDITIONS. THE SNOW WILL BE WINDING
DOWN OVER CENTRAL AND NORTHEAST WISCONSIN POST 15Z WITH TOTAL
ACCUMULATIONS OF 2-4 INCHES AND 1-3 INCHES RESPECTIVELY.
HOWEVER...NW WINDS AND GROWING INSTABILITY OVER WESTERN LAKE
SUPERIOR WILL SET UP GOOD CONDITIONS FOR LAKE EFFECT SNOW. SOME
QUESTIONS ON THE EXACT WIND DIRECTION...AS 1000-850MB WINDS BACK
AROUND TO THE 320-330 DEGREE DIRECTION LATE SUNDAY MORNING AND INTO
THE AFTERNOON. AS A RESULT...BEST CONDITIONS FOR BEEFY SNOW
ACCUMULATIONS MAY HAVE TO WAIT UNTIL SUNDAY NIGHT WITHIN THE SNOW
BELT. WILL STILL KEEP 2-4 INCHES IN THE FORECAST THOUGH. ONCE THE
SNOW DIMINISHES OUTSIDE THE SNOW BELT...WIND GUSTS WILL REMAIN AN
ISSUE FOR THE REST OF THE DAY. GUSTS WILL LIKELY FALL IN THE 40-50
MPH RANGE...AND THE HIGHEST GUSTS SHOULD FALL OVER CENTRAL AND
NORTHEAST WISCONSIN. HAVE POSTPONED THE START OF THE WIND ADVISORY
UNTIL 18Z EVERYWHERE...FIGURING THE MORNING SNOW WILL HAVE POTENTIAL
TO BLOW AROUND THROUGH AT LEAST MIDDAY. WILL SEE MORNING HIGHS IN
THE MID 20S TO LOWER 30S FALL THROUGH THE DAY.
AS FOR HEADLINES...ALREADY MENTIONED THE WIND ADVISORY. HAVE
DELAYED THE WINTER HEADLINES UNTIL 06Z TONIGHT FOR NORTH-CENTRAL
WISCONSIN AND UNTIL 09Z FOR NORTHEAST WISCONSIN (EXCEPT FOR THE DOOR
WHICH STARTS AT 12Z). STUCK WITH THE WINTER WEATHER ADVISORY
BECAUSE FIGURING SNOW AMOUNTS WILL BE IN THE 2-4 INCH RANGE AT THE
HIGHEST END...AND THE SNOW WILL BE WINDING DOWN AS THE WINDS CRANK
UP SUNDAY MORNING. THERE MAY BE A SHORT WINDOW OF A COUPLE HOURS OF
LOW VSBYS (SAY A HALF MILE OR LESS)...BUT FELT THE MARGIN OF ERROR
IS TOO HIGH FOR AN UPGRADE TO A WINTER STORM WARNING. COMBINED WITH
UNCERTAINTY IN MODEL PERFORMANCE...HAVE STUCK WITH A WINTER WEATHER
ADVISORY FOR NOW.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY.
CYCLONIC UPPER FLOW WILL PRODUCE LAKE EFFECT SNOW IN FAR
NORTHCENTRAL WISCONSIN AND SNOW SHOWERS OR FLURRIES SUNDAY NIGHT
THROUGH MONDAY. MONDAY SHOULD BE THE COLDEST DAY OF THE WINTER SO
FAR WITH HIGHS IN THE HIGH SINGLE NUMBERS AND TEENS ALONG WITH A
GUSTY WIND PRODUCING WIND CHILLS BELOW ZERO. 850 MB TEMPERATURES
FORECAST TO FALL TO NEAR -20C LATE SUNDAY NIGHT AND MONDAY MORNING
CREATING IMPRESSIVE INSTABILITY OVER LAKE SUPERIOR. WIND DIRECTIONS
ARE NOT IDEAL (A LITTLE TOO MUCH WESTERLY COMPONENT) FOR VILAS
COUNTY AND THE WIND SPEEDS ARE ACTUALLY STRONGER THAN IDEAL (WINDS
MORE THAN 40 KNOTS DOES NOT PERMIT DRY AIR TO PICK UP MUCH
MOISTURE IF IT TRAVEL SO FAST ACROSS THE LAKE). SO THINK THAT WE
WILL SEE ANOTHER 3 TO 5 INCHES ACROSS VILAS COUNTY FOR THE SUNDAY
EVENING THROUGH MONDAY NOON WITH LOCALLY HIGHER AMOUNTS NEAR THE
MICHIGAN BORDER.
UPPER RIDGING BEGINS TO ARRIVE MONDAY EVENING WHICH WILL CAUSE
WINDS TO BACK SUFFICIENTLY TO DIMINISH THE LAKE EFFECT SNOW TO
JUST FLURRIES. A CLIPPER SYSTEM WILL BRING INCREASING CLOUDS
TUESDAY AND MAYBE SOME SNOW SHOWERS TUESDAY NIGHT. NO MUCH
EXPECTED DUE TO VERY DRY AIR IN PLACE BEFORE IT/S ARRIVAL. THEN
MORE UPPER RIDGING FOR WEDNESDAY NIGHT THROUGH FRIDAY WITH MAINLY
DRY AND MILD WEATHER. A BIG DIFFERENCE IN THE MODELS FOR NEXT
SATURDAY OVER THE WESTERN GREAT LAKES SO MADE NO CHANGES TO
PREVIOUS FORECAST FOR THAT PERIOD.
&&
.AVIATION...LOW CLOUDS ARE PUSHING NORTHEAST NORTH OF A WARM FRONT
OVER THE NORTHERN MISSISSIPPI VALLEY. EXPECT THIS TO CONTINUE THIS
AFTERNOON...THOUGH SOME BREAKS AND IMPROVING VISIBILITIES ARE
POSSIBLE OVER THE FOX VALLEY. WENT OPTIMISTIC IN THIS
REGARD...WHICH HAS SUPPORT FROM THE LATEST VISIBLE SATELLITE. A
DYNAMIC LOW PRESSURE SYSTEM THEN WILL SWING NORTHEAST ACROSS THE
PLAINS THIS EVENING...AND SOUTHERN WISCONSIN OVERNIGHT. PRECIP IS
ANTICIPATED TO SPREAD FROM WEST TO EAST ACROSS THE TAF SITES
STARTING AROUND MIDNIGHT OVER CENTRAL WISCONSIN. PRECIP TYPE SHOULD
BE MOSTLY SNOW OVER NORTH-CENTRAL WISCONSIN WHERE TEMPS ALOFT ARE
SLIGHTLY COOLER...BUT A MIX WILL LIKELY START THINGS OFF OVER THE
FOX VALLEY. SNOW WILL CONTINUE THROUGH THE MORNING...WITH ACCUMS
AROUND 2 INCHES OVER CENTRAL WISCONSIN AND THE FOX VALLEY...AND UP
TO 4 INCHES AROUND RHI.
STRONG SURFACE WINDS MAY BE A HAZARD SUNDAY AS DEEP LOW PRESSURE
MOVES BY TO OUR SOUTH. SUSTAINED WEST TO NORTHWEST WINDS OF 25 TO
35 KNOTS WITH GUSTS TO 45 KNOTS POSSIBLE.
MPC
&&
.MARINE...SOUTH WINDS AHEAD OF AN APPROACHING ARCTIC FRONT COULD
CAUSE HAZARDOUS CONDITIONS FOR SMALL CRAFTS THIS AFTERNOON AND
TONIGHT. AS THE ARCTIC COLD FRONT SWEEPS EAST OF THE AREA LATE
TONIGHT....WEST TO NORTHWEST GALES WILL DEVELOP SUNDAY MORNING
WHICH WILL CONTINUE INTO MONDAY AFTERNOON. THERE IS AN OUTSIDE
CHANCE THAT GUSTS COULD APPROACH OR REACH STORM FORCE OVER
NORTHERN DOOR COUNTY SUNDAY NIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 AM TO NOON CST SUNDAY FOR WIZ013-
020-021-031-037-038-045-048-073-074.
WIND ADVISORY FROM NOON SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
WIZ010>013-018>021-030-031-035>040-045-048>050-073-074.
WINTER WEATHER ADVISORY FROM 6 AM TO NOON CST SUNDAY FOR WIZ022-
039-040-049-050.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY
FOR WIZ010>012-018-019-030-035-036.
WIND ADVISORY FROM NOON SUNDAY TO 6 PM CST MONDAY FOR WIZ022.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY
FOR WIZ005.
&&
$$
MPC/MPC
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1050 AM CST SAT DEC 31 2011
.UPDATE...
VISIBLE SATELLITE CLEARLY SHOWING WHERE DENSE FOG AND LIGHT FOG IS
SET UP ACROSS SOUTH CENTRAL AND SOUTHEAST WI. EXTENDED THE DENSE FOG
ADVY UNTIL NOON SINCE IT IS SLOW TO MIX OUT. NOT SURE IF IT IS
VERIFYING IN JEFFERSON AND WALWORTH COUNTIES...BUT KEPT IT GOING.
ALSO INCLUDED SHEBOYGAN COUNTY UNTIL NOON DUE TO DENSE FOG OVER THE
EASTERN HALF OF THE COUNTY AND ALSO THE NEARSHORE MARINE ZONE.
12Z MODELS ARE COMING IN VERY STRONG WITH THIS SYSTEM FOR
TONIGHT...STRONGER THAN PREVIOUS RUNS. VERY IMPRESSIVE PRESSURE
RISE-FALL COUPLETS...STRONG Q-VECTOR CONVERGENCE...ETC. CURRENT
WATER VAPOR IMAGERY SHOWING THE VERY STRONG SHORTWAVE DIGGING INTO
WESTERN KANSAS WITH A NEUTRAL TILT DEVELOPING IN RUC 500MB HEIGHT
FIELD. NEW NAM AND GFS AND CANADIAN MODELS ARE SHOWING MORE OF A
NEGATIVE TILT IN THE 500MB HEIGHTS RIGHT OVER WI AT 12Z SUN. THEY
ARE ALSO SHOWING TWO VORT MAXES COMING ACROSS...WITH THE FIRST ONE
HITTING SOUTHERN WI AROUND 06Z AND THE SECONDARY ONE AROUND 18Z SUN.
THE SECONDARY VORT MAX BRINGS WITH IT A VERY STRONG PV
ANOMALY...WHICH COULD HAVE SOME IMPACT ON LINGERING SNOW SHOWERS AND
STRONG WINDS.
WE WILL BE CONSIDERING UPGRADING THE WINTER WEATHER ADVISORY TO
HIGHER HEADLINES FOR SOME PORTIONS OF OUR FORECAST AREA. STAY TUNED.
THIS IS A STRONG SYSTEM TONIGHT/SUN MORNING. VISIBILITIES MAY BE
GREATLY REDUCED WITH THE BLOWING SNOW. ADDITIONALLY...ANY RAIN THAT
FALLS WILL LIKELY FREEZE AS TEMPS FALL BELOW FREEZING OVERNIGHT AND
SNOW WILL FALL ON TOP OF THE FROZEN SURFACES...CREATING HAZARDOUS
CONDITIONS.
&&
.AVIATION/18Z TAFS/...AREA OF STRATUS AND FREEZING FOG OVER SOUTH
CENTRAL WI THIS MORNING WILL GRADUALLY MIX OUT BY NOON OR WORST CASE
SCENARIO EARLY AFTERNOON. TAF SITES WILL EXPERIENCE VLIFR CONDITIONS
WITHIN THE FOG AND STRATUS. MOSTLY VFR CONDITIONS WILL THEN RETURN
LATER THIS AFTERNOON AND EVENING.
LOW PRESSURE APPROACHING FROM IA WILL BRING LIGHT RAIN AND LIGHT
SNOW TO THE REGION. THE LOW AND STRONG COLD FRONT WILL PASS ACROSS
SRN WI SUNDAY MORNING WITH RAIN CHANGING TO SNOW AND STRONG WNW
WINDS GUSTING TO 50 MPH OR HIGHER. IFR TO LIFR CONDITIONS WILL
RETURN WITHIN THE STRONG WINDS AND SNOW THROUGH SUNDAY MORNING.
THIS IS A STRONG SYSTEM TONIGHT/SUN MORNING. VISIBILITIES MAY BE
GREATLY REDUCED WITH THE BLOWING SNOW. ADDITIONALLY...ANY RAIN THAT
FALLS WILL LIKELY FREEZE AS TEMPS FALL BELOW FREEZING OVERNIGHT AND
SNOW WILL FALL ON TOP OF THE FROZEN SURFACES...CREATING HAZARDOUS
CONDITIONS.
&&
.MARINE...
A STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS LAKE MICHIGAN TONIGHT
AND SUNDAY. WILL KEEP SMALL CRAFT ADVY FROM THIS EVENING THROUGH
EARLY SUN MORNING FOR SOUTHERLY WINDS AHEAD OF THE SYSTEM...THEN
EXPECTING A SHORT PERIOD OF RAMP-UP BETWEEN THE SMALL CRAFT TO GALE
TO STORM SUN MORNING. UPGRADED THE GALE WARNING TO STORM WARNING FOR
SUN MORNING THROUGH LATE SUN NIGHT. WESTERLY WINDS WITH THE COLD
FRONT WILL HAVE QUITE A SURGE OF WINDS WITH THEM...THEN CONTINUE
WITH STRONG SUSTAINED GALES WITH FREQUENT STORM GUSTS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZING FOG ADVISORY UNTIL NOON CST TODAY FOR WIZ052-056-057-
062>064-067>070.
WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM CST SUNDAY FOR WIZ046-
047-056-057-062-063-067-068.
WIND ADVISORY FROM 9 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
WIZ046-047-056-057-062-063-067-068.
WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
WIZ064>066-069>072.
WINTER WEATHER ADVISORY FROM 6 AM TO NOON CST SUNDAY FOR WIZ051-
052-058>060.
WIND ADVISORY FROM NOON SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR
WIZ051-052-058>060.
LM...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY
FOR LMZ643>646.
STORM WARNING FROM 6 AM SUNDAY TO 6 AM CST MONDAY FOR LMZ643>646.
DENSE FOG ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR LMZ643.
&&
$$
UPDATE...MRC
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1035 AM EST Mon Jan 2 2012
.UPDATE (Today through Tonight)...
Previous forecast appears on track and no significant changes
are anticipated.
15Z water vapor and H4 RUC analysis now showing a high amplified
northern stream upper level pattern across North America. This flow
consists of high amplitude ridging over the inter-mountain
west...followed downstream by an impressive and still sharpening
trough over the eastern half of the nation. KTLH sounding
experienced technical problems this morning preventing a full
sounding profile, however WV imagery and the crystal clear skies out
the window suggest an already very dry column through a deep layer
of the troposphere. Upstream from our area we see a strong 140+ knot
upper level jet beginning to propagate down the backside of the
upper trough. This energy will help to further amplify the trough
this evening and bring about significant changes in our local
weather.
At the surface,
The cold front from Sunday evening is now well south of our area
across the southern FL peninsula. A cooler and drier airmass has
arrived in its wake with temperatures in the 50s, as opposed to
Sunday`s 70s. Winds are also rather gusty with a tight gradient
between the front and a strong 1040+mb surface high building across
the mid-section of the country. The wind advisory remains in effect
for the entire region through the day as efficient diurnal mixing
eventually allows stronger winds a few thousand feet aloft to mix
down to the surface. As mentioned above, ongoing weak cold air
advection will help keep temperatures in check this afternoon, and
only anticipate highs in the lower/mid 50s north and mid/upper 50s
south.
Tonight,
Big changes occur this evening as the upper jet max, and associated
shortwave impulse rotate across the southeastern states. This
impulse will push an secondary arctic cold front quickly across the
forecast area. In the wake of this front, the "flood-gates" in terms
of cold air will open. 850mb temps are progged to plummet 8-10C over
most areas between 00UTC and 06UTC. Temperatures at the surface will
fall below freezing at most area by around 3-4AM and likely remain
below freezing until several hours after sunrise. In fact, often
with these overnight arctic cold frontal passages, we experience the
low temperatures a hour or 2 after sunrise, as strong CAA advection
overwhelms any early morning solar addition. Speaking of lows, we
are looking for widespread mid/upper 20s, with upper 20s to around
30 at the immediate coast. Add in a steady NW wind and wind chills
are expected to reach the upper teens in many locations around
sunrise Tuesday morning. Should these wind chill reading continue to
be anticipated with the afternoon forecast package, a wind chill
advisory will become necessary in addition to the freeze warning
already in effect.
&&
.AVIATION...
(through 18Z Tuesday) VFR VFR conditions will prevail through the
forecast period and beyond. Stronger winds will mix down to the
surface by midday allowing gusts of 25 to 30 mph at times. Winds
will remain 10 to 15 mph and gusty overnight tonight as another cold
front brings a surge of arctic air to the area. A period with
potential LLWS will occur during the later evening and early morning
hours tonight in the wake of this front. This potential will be
examined more closely for the 18Z TAF cycle.
&&
.MARINE...
Advisory level northerly winds are occurring across the forecast
waters in the wake of a cold front. A stronger secondary cold front
will cross the area this evening. High end advisory level winds and
rough seas are expected overnight into Tuesday morning. Based on the
expected the degree of cold air advection, and the latest low level
BUFR profiles, wind gusts of 35 to 40 knots are becoming more
likely. The best timing for gale force gusts will fall between late
evening and sunrise. Winds and seas will then gradually diminish
later Tuesday into Tuesday night as high pressure builds over the
Northeast Gulf of Mexico.
&&
.FIRE WEATHER...
A cold front pushed across the Tri-State Area late Sunday, and
colder and much drier air will be spreading across the area today
and tonight, on the heels of strong gusty northwest winds. Critical
values of relative humidity plus strong 20 foot winds will combine
to produce Red Flag conditions across the entire Tri-State Area
later today, and a Red Flag Warning has been issued for all of our
Alabama, Georgia and Florida counties. On Tuesday, durations of low
relative humidity will likely meet Red Flag criteria across our
Florida counties, and there is a high probability that they will
meet criteria across our Georgia counties as well. In southeast
Alabama, durations will be marginal and the 20 foot winds are not
expected to meet criteria. However, due to the uncertainty in the
forecast, a Fire Weather Watch has been issued for all of our
Florida, Georgia and Alabama counties for Tuesday, and conditions
will need to be closely monitored. In addition, a secondary cold
front will sweep across the area later this evening, and very cold
arctic air will spread across the area tonight and Tuesday. Expect a
long duration widespread freeze event tonight, and again on Tuesday
night into Wednesday morning. Finally, with very dry air remaining
in place across much of the area through Wednesday, conditions will
need to be monitored for possible Red Flag warnings, mainly across
our Florida counties again on Wednesday afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 57 27 43 18 52 / 0 0 0 0 0
Panama City 59 28 46 28 54 / 0 0 0 0 0
Dothan 56 27 42 24 53 / 0 0 0 0 0
Albany 56 26 42 22 52 / 0 0 0 0 0
Valdosta 56 26 42 21 52 / 0 0 0 0 0
Cross City 60 27 45 18 53 / 0 0 0 0 0
Apalachicola 60 34 46 26 53 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Freeze Warning from Midnight tonight to 8 AM CST Tuesday for
Coffee-Dale-Geneva-Henry-Houston.
Fire Weather Watch from 11 AM CST this morning through this
afternoon for Coffee-Dale-Geneva-Henry-Houston.
Wind Advisory until Midnight CST tonight for Coffee-Dale-Geneva-
Henry-Houston.
GA...Freeze Warning from 1 AM to 9 AM EST Tuesday 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.
Fire Weather Watch from Noon EST today through this afternoon
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.
Wind Advisory until 1 AM EST Tuesday 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 1 AM EST /Midnight CST/ to 9 AM EST /8 AM
CST/ Tuesday 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.
Fire Weather Watch from Noon EST /11 AM CST/ today through this
afternoon 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.
Wind Advisory until 1 AM EST /Midnight CST/ Tuesday 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...Gale Watch through Tuesday morning for Apalachee Bay-Coastal
waters From Ochlockonee River to Apalachicola FL out to 20
NM-Coastal waters from Suwannee River to Keaton Beach FL
out 20 NM-Coastal waters from Apalachicola to Destin FL out
20 NM-Waters from Suwannee River to Apalachicola FL from 20
to 60 NM-Waters from Apalachicola to Destin FL from 20 to
60 NM.
&&
$$
MROCZKA/EVANS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
919 AM EST MON JAN 2 2012
.SYNOPSIS...
ARCTIC HIGH PRESSURE WILL BRING COLD AND DRY CONDITIONS THROUGH MID
WEEK WITH BRISK NORTHWEST WINDS. THE COLDEST TEMPERATURES SINCE LAST
WINTER ARE EXPECTED TUESDAY NIGHT WITH LOWS IN THE TEENS OR LOWER
20S EXPECTED. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH
WEDNESDAY...MODERATING LATE IN THE WEEK AND THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...THE FIRST COLD FRONT IS NOW WELL OFFSHORE AND
COOLER NORTHWEST WINDS COVER THE CAROLINAS. THE STRONG NORTHWEST
FLOW ACROSS THE MOUNTAINS HAS SET UP A LEE-SIDE TROUGH EXTENDING
FROM ROANOKE TO HICKORY TO GREENVILLE SC...AND IN RESPONSE A
MESOSCALE RIDGE HAS POKED UP THROUGH THE SC/NC PIEDMONT REGION. THIS
EFFECT APPEARS TO BE WELL-MODELED IN THE LATEST RUC MODEL WHICH
SHOWS LIGHTER WINDS THAN INITIALLY EXPECTED ACROSS THE EASTERN
CAROLINAS THIS AFTERNOON. MORE IMPORTANTLY TO OUR FORECAST...THE 12Z
BALLOON SOUNDINGS FROM MOREHEAD CITY...CHARLESTON SC...AND
GREENSBORO SHOWED THE LOWER ATMOSPHERE UP TO THE 850 MB LAYER
AVERAGED 2 DEGREES FAHRENHEIT WARMER THAN ANY MODEL HAD FORECAST
THIS MORNING. WE HAVE RAISED HIGHS NOT-COINCIDENTALLY BY 2 DEGREES
ACROSS THE BOARD TODAY...WITH MID 50S NOW EXPECTED FOR MOST AREAS.
NO CHANGES ARE EXPECTED FOR TONIGHT. AS STRONG UPPER LEVEL TROUGH
WILL PUSH OFF THE COAST OVERNIGHT WITH TREMENDOUS COLD ADVECTION
DEVELOPING. 850 MB TEMPERATURES WILL FALL FROM AROUND -5C TO -6C
THIS EVENING TO A BONE-CHILLING -13C BY DAYBREAK TUESDAY. A
DEEPLY-MIXED BOUNDARY LAYER WILL BE TOPPED OFF BY SOME HIGH
STRATOCUMULUS/LOW ALTOCUMULUS CLOUDS TONIGHT WHICH HAPPEN TO FORM
RIGHT WITHIN THE -12C TO -18C TEMPERATURES FOR EFFICIENT DENDRITIC
SNOW CRYSTAL GROWTH. A DEEP AND VERY DRY SUBCLOUD LAYER SHOULD BE
ENOUGH TO PREVENT ANY SNOW FLURRIES FROM REACHING THE GROUND OVER
OUR PORTION OF THE CAROLINAS...BUT WE WILL LOOK AGAIN AT THE 12Z
GUIDANCE FOR ANY DISCERNIBLE TRENDS IN BOUNDARY LAYER MOISTURE
CONTENT TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...RAW AND BITTERLY COLD TUESDAY WITH HIGHS IN THE
30S AND WIND CHILLS STUCK IN THE 20S ALL DAY FOR MOST OF THE REGION.
THE REGION WILL BE IN THE THROES OF ARCTIC AIR THROUGH THE
PERIOD...BUT TUESDAY AND TUESDAY NIGHT WILL BRING THE COLDEST OF THE
COLD. FIERCE COLD ADVECTION SHUTS OFF EARLY TUESDAY WITH THE PASSING
OF THE LOW LEVEL THERMAL TROUGH. SAID TROUGH WILL HAVE 850MB TEMPS
BOTTOMED OUT AT AN IMPRESSIVE -13C OR ABOUT 9F. THIS IS COLD ENOUGH
THAT DESPITE A GOOD 6-7KFT OF MIXING HIGH TEMPERATURES WILL STAY IN
THE 30S. GUSTY NW WINDS COULD EASILY REACH 30 MPH AT TIMES KEEPING
THE WIND CHILL NOT ONLY BELOW FREEZING BUT POSSIBLY IN THE 20S ALL
AFTERNOON. SINGLE DIGIT DEWPOINTS PAIRED WITH THE WIND WILL MAKE FOR
SOME FIRE WX CONCERNS AS WELL. TUESDAY NIGHT WILL BE THE COLDEST
PERIOD OF THE ARCTIC INVASION...BUT THERE IS SOME UNCERTAINTY ABOUT
HOW IDEALIZED OF A RADIATIONAL COOLING SETUP IS IN PLACE. GUIDANCE
SUGGESTING THAT THE HIGH MAY BE SUPPRESSED WELL ENOUGH TO THE SOUTH
TO KEEP A FEW MPH OF WIND ALL NIGHT. INDEED FCST SOUNDINGS DO NOT
SHOW THE VERY STEEP SFC BASED INVERSION TYPICAL OF AN ARCTIC RAD
COOLING NIGHT.
WITH THE HIGH OFF TO THE SOUTH THERE IS A SMALL SOUTHERLY COMPONENT
TO THE SURFACE FLOW BY WED. MIXING WILL BE MORE SHALLOW AS COMPARED
TO TUESDAY SO ANY WARMUP WILL BE QUITE GRADUAL. WEDNESDAY HIGHS IN
THE UPPER 40S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...SHARP UPPER TROUGH OVER THE NORTHEASTERN U.S.
WILL BE LIFTING OUT ON THU ALLOWING FOR WEAK HEIGHT RISES OVER
MUCH OF THE EAST WHILE WEAK SFC RIDGE BUILDS IN. THE HIGH PROGRESSES
EAST AND END SUP OFF THE COAST BY FRIDAY NIGHT ALLOWING A RETURN OF
ABOVE CLIMO TEMPS AND SOME MOISTURE ADVECTION. A VERY WEAK SOUTHERN
BRANCH FEATURE NOW STAYS FAR ENOUGH TO OUR SOUTH OVER THE WEEKEND TO
BE OF ANY CONSEQUENCE. A COLD FRONT MAY ENTER AND STALL ACROSS THE
AREA ON SUNDAY...BEING LARGELY LINED UP WITH THE WSW FLOW ALOFT.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...A COLD FRONT HAS MOVED OFFSHORE AND IR SATELLITE LOOPS
INDICATE CLEAR SKIES IN THE WAKE OF THE FRONT. WITH AN EVEN DRIER
AIRMASS MOVING INTO THE TERMINALS THERE IS HIGH CONFIDENCE OF
VFR/CLEAR SKIES THROUGH THIS AFTERNOON. GUSTY NORTHWEST WINDS WILL
GRADUALLY ABATE BY NOON. WINDS WILL BECOME PROGRESSIVELY WESTERLY BY
AFTERNOON.
WINDS WILL FURTHER DECREASE TO 5-7 KNOTS AND BECOME WEST-SOUTHWEST
TO WEST BY LATE AFTERNOON/EARLY EVENING AS ANOTHER COLD FRONT
APPROACHES. THE FRONT SHOULD MOVE THROUGH ALL TERMINALS FROM
NORTHWEST TO SOUTHEAST DURING THE EVENING. STRONG LIFT IS INDICATED
WITH THE FRONT BUT MOISTURE IS LIMITED. DO NOT EXPECT ANY
PRECIPITATION BUT THERE COULD BE A SHORT PERIOD OF CEILINGS AROUND
5K. WINDS WILL SHIFT BACK TO THE NORTHWEST WITH FROPA AS SKIES CLEAR.
NOTE...DUE TO AN ASOS OUTAGE THE KFLO TAF WILL INDICATE AMD NOT SKED
UNTIL OBSERVATIONS ARE AGAIN AVAILABLE.
EXTENDED OUTLOOK...VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM MONDAY...THE COLD FRONT IS WELL OFFSHORE AND COOL
NORTHWEST WINDS ARE IN PLACE ACROSS THE COASTAL WATERS. THE COLD
FRONT OFFSHORE IS A PRESSURE TROUGH ITSELF...AND THERE IS A LEE-SIDE
TROUGH OF LOW PRESSURE IN THE NC/SC FOOTHILLS AS WELL. BETWEEN THESE
TWO SYSTEMS A SMALL-SCALE RIDGE OF RELATIVE HIGH PRESSURE HAS
DEVELOPED ACROSS THE NC/SC PIEDMONT REGION. WINDS ARE LIGHTER NEAR
THIS RIDGE...AND THIS SHOULD HELP INSULATE THE REGION FROM ANY
STRONGER WIND SPEEDS UNTIL TONIGHT. NORTHWEST WINDS IN THE 15-20 KT
RANGE THIS MORNING WILL COME DOWN MORE INTO THE 15 KT RANGE THIS
AFTERNOON...BUT INCREASING RAPIDLY THIS EVENING AS A STRONG UPPER
LEVEL DISTURBANCE SHOOTS OFF THE COAST AND TREMENDOUSLY COLD AIR
BEGINS TO POUR OFF THE COAST AND OVER THE COASTAL WATERS. THIS IS
WHEN WINDS COULD INCREASE TO GALE FORCE FOR SEVERAL HOURS.
SEAS RANGE FROM 2-4 FT ACROSS THE COASTAL WATERS THIS MORNING WITH
LITTLE CHANGE EXPECTED THROUGH THE DAY. SEAS WILL REALLY INCREASE
TONIGHT ESPECIALLY FOR LOCATIONS GREATER THAN 5-10 MILES FROM THE
COAST DUE TO INCREASING EFFECTIVE FETCH LENGTH WITH THE NORTHWEST
WINDS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...STRONG GRADIENT AND DEEP MIXING CAUSED BY
EXTREME COLD/STEEP LAPSE RATES WILL SPONSOR STRONG WINDS FOR MOST OF
THE PERIOD. THIS WILL BE MOST PREVALENT ON TUESDAY WHEN THE COLD AIR
AND GRADIENT WILL BE AT THEIR STRONGEST. GUSTS TO GALE FORCE TOUGH
TO RULE OUT BUT CURRENT WRF FORECAST CAPS 850MB FLOW AT 30KT. THE
SURFACE GRADIENT AND GUSTINESS RELATED TO THE LOW LEVEL JETTING WILL
BOTH DECREASE TUESDAY NIGHT AS HIGH PRESSURE BUILDS INTO FLORIDA AND
NE GOMEX...FLAGS WILL BE ABLE TO BE LOWERED. THIS HIGH NOW GETS
QUICKLY SUPPRESSED TO THE SOUTH BY WED AFTERNOON BRINGING LIGHT
WINDS THAT WILL BACK TO SWRLY.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...A MODERATE OFFSHORE/NW GRADIENT WIND REMAINS IN
PLACE EARLY THURSDAY BUT A QUICK ABATEMENT TO AROUND 10KT BY
AFTERNOON IS EXPECTED AS HIGH PRESSURE SETTLES ACROSS FL AND NE
GOMEX. AS THE ANTICYCLONE PROGRESSES EAST AND ENDS UP NE OF BAHAMAS
BY FRIDAY WIND LOCALLY BACKS TO SW WHILE SPEEDS REMAIN FAIRLY
CONSTANT. SEAS COMPRISED OF MAINLY SHORT PERIOD WIND WAVES AND WILL
AVG 2 TO 3 OR 2 TO 4 FT THROUGH THE PERIOD.
&&
.FIRE WEATHER...
THE DRIEST AIR OF THE SEASON WILL CONTINUE TO MOVE INTO THE AREA
TODAY AND PERSIST INTO MID WEEK. THIS DRY AIR COUPLED WITH GUSTY NW
WINDS MAY SERVE TO INCREASE THE FIRE DANGER ACROSS THE AREA. THE
WORST OF THESE CONDITIONS ARE EXPECTED ON TUESDAY. MINIMUM RELATIVE
HUMIDITY WILL BE NEAR OR BELOW CRITICAL VALUES AND WINDS WILL BE
CLOSE TO THRESHOLD AS WELL...MAINLY IN GUSTS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WARNING FROM 6 PM THIS EVENING TO 7 AM EST TUESDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...MRR
FIRE WEATHER...RJD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1036 AM EST MON JAN 2 2012
.SYNOPSIS...
STRONG UPPER LEVEL LOW AND ARCTIC AIRMASS RESULTS IN WIND BLOWN SNOW
SHOWERS THROUGH TUESDAY. WEAKER COLD FRONT MOVES THROUGH WEDNESDAY.
DRY WITH MODERATING TEMPERATURES FOR THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST RADAR MOSAIC SHOWS AREAS OF SNOW...SOME HEAVY...MOVING EAST
ACROSS THE FORECAST AREA. RADAR INDICATES A FEW MESOSCALE FEATURES
IN THE FLOW...WITH SOME OF THE HEAVIER SNOW BEING PRODUCED BY THESE
FEATURES.
UPPER LEVEL FEATURE...WHICH IS STILL LOCATED NORTHWEST OF REGION...
IS EXPECTED TO APPROACH THE AREA LATER TODAY. THIS SHOULD FURTHER
ENHANCE THE SNOW.
CURRENT FORECAST IS PRETTY MUCH ON TRACK. HOWEVER...WILL TAKE A LOOK AT
SNOWFALL FORECAST TO SEE IF WE MIGHT NEED TO BUMP IT UP IN A FEW
LOCATIONS FOR TODAY.
PREVIOUS DISCUSSION...
IR SATELLITE IMAGERY SHOWING MID AND LOW LEVEL CLOUD DECK
APPROACHING WESTERN FLANKS. A RIDGE OF LOW H85 MOISTURE WAS
EVIDENT AHEAD OF THIS CLOUD DECK...WHICH LED TO CLEARING OVER
CENTRAL PORTIONS OF CWA. THIS SHOULD FILL IN QUICKLY OVER NEXT
SEVERAL HOURS.
RUC H85 MOISTURE ACCURATELY DEPICTING MOISTURE ASSOCIATED WITH LOW
AND MID LEVEL CLOUDS STREAMING DOWNSTREAM OF THE GREAT LAKES. CURRENT H85
TEMPS FROM RUC ARE ABOUT -9C. WITH RUC H925 TEMPS ABOUT -3C...LAPSE
RATES ARE STEEPENING AND SHOULD CONTINUE WITH ADDITIONAL CAA. STEEP
LAPSE RATES AND ADDED DEEP MOISTURE WILL ONLY ADD TO THE SPATIAL
COVERAGE OF SNOW SHOWERS ALREADY DEVELOPING NW INTO CENTRAL OHIO.
KEPT SNOW TOTALS CLOSE TO PREVIOUS FORECAST...BUT DID TWEAK EKN
VICINITY UP A BIT AS THAT AREA RECEIVED A QUICK 1.5 INCHES OF NEW
SNOW BEFORE MIDNIGHT...THIS SNOW COMING BEFORE THE REAL MOISTURE
ARRIVES. PLAN TO KEEP ADVISORIES THE SAME AS PREVIOUS FORECAST.
BELIEVE OUR NW WV COUNTIES COULD COME CLOSE TO MEETING ADVISORY
CRITERIA FOR SNOW TOTALS IN 12HR TIME FRAME...BUT WOULD LIKE TO SEE
TRENDS IN INITIAL SNOW DEVELOPMENT FIRST.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
COLD AIR ADVECTION CONTINUES INTO TUESDAY AFTERNOON. MODELS SHOWING
LAKE PLUMES ALSO EFFECTING THE AREA...ALTHOUGH DEEPER MOISTURE PULLS
OUT IN THE MORNING. SHOULD BE PLENTY OF SNOW FLAKES AROUND...BUT
ACCUMULATIONS SHOULD BE LIMITED...WITH THE BEST ACCUMULATIONS IN THE
LAKE PLUMES. WARM AIR ADVECTION THEN SETS IN FOR TUESDAY NIGHT...AND
SHOULD BRING AN END TO THE SNOW.
ANOTHER MUCH WEAKER SYSTEM SKIRTS NORTHERN PORTIONS OF THE REGION ON
WEDNESDAY AND WEDNESDAY NIGHT. COULD SEE SOME LIGHT SNOW IN THE
NORTHERN COUNTIES...BUT THIS SYSTEM IS FAIRLY MOISTURE STARVED...SO
WILL KEEP POPS LOW.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
ONE LAST UPPER LEVEL S/W TROF MOVES SE THROUGH THE AREA IN THE
LARGER SCALE NW FLOW ALOFT RIGHT AT THE START OF THE PERIOD.
UPSLOPE FLOW IN ITS WAKE SHOULD BRING LIGHT SNOW SHOWERS OR
FLURRIES TO THE MOUNTAINS WED NT INTO THU MORNING. WITH HEIGHTS
QUICKLY LIFTING THU...EXPECT THE AIR MASS IN THE WAKE OF THE FRONT
TO NOT BE QUITE AS COLD AS ITS PREDECESSOR...AND THE UPSLOPE EVENT
NO WHERE NEAR THE DURATION OR MAGNITUDE OF ITS PREDECESSOR.
HIGH PRESSURE CROSSES THU NT...FOLLOWED BY SW FLOW ON ITS BACK SIDE
FRI INTO THE WEEKEND. NEXT NORTHERN STREAM UPPER LEVEL S/W TROUGH
DRIVES SURFACE COLD FRONT THROUGH THE AREA OVER THE WEEKEND...WITH
MODEL DIFFERENCES ON TIMING. MOISTURE GETS DRAWN UP AHEAD OF THE
FRONT INTO THE FORECAST AREA JUST AS THE FRONT APPROACHES SAT
MORNING. AIR MASS BEHIND FRONT DOES NOT IT LEAST INITIALLY APPEAR
TO BE AS COLD AS THE ONE CHARGING THROUGH EARLY THIS WEEK.
UPPER LOW FORMS OVER THE SWRN CONUS EARLY IN THE WEEKEND IN RESPONSE
TO RIDGING OFF THE W COAST. MODELS THEN START TO EJECT THIS LOW
NEWD LATE IN THE WEEKEND WITH SOME TIMING DIFFERENCES IN TANDEM WITH
SIMILAR DIFFERENCES IN THE NORTHERN STREAM.
BLENDED IN MEX / HPC FOR TEMPERATURES...NO SIGNIFICANT CHANGES.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
LOW LEVEL MOISTURE PLUME EVIDENT ON WATER VAPOR IMAGERY STARTING
MOVE INTO OUR AREA. HAVE CIGS DROPPING TO MVFR W TO E OVER NEXT FEW
HOURS WITH ARRIVAL OF THIS MOISTURE. WILL KEEP MVFR CIGS OVER
LOWLAND COUNTIES THROUGH TODAY...HOWEVER VSBYS WILL DROP TO IFR OR
LOWER IN SHSN TODAY AND TONIGHT. EXPECT VSBYS TO BOUNCE UP AND
DOWN TODAY...THUS WILL INCLUDE TEMPO GROUPS TO COVER THIS. IN THE
MOUNTAINS OF WV EXPECTING CIGS AND VSBYS TO BE IFR AND BOUNCING IN
AND OUT OF LIFR IN INDIVIDUAL SHSN. IFR TO LIFR COULD PERSIST IN
THE MOUNTAINS FOR QUITE SOME TIME...EVEN BEYOND THE SCOPE OF THIS
ISSUANCE.
EXPECTING A SLOW DECREASE IN THE WIND GUSTS WHICH ARE ALREADY
EVIDENT IN THE OBSERVATIONS. SUSTAINED WINDS ARE NOT EXPECTED TO
DROP BELOW 12KTS TO 15KTS THROUGH 00Z TUESDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE:HIGH.
ALTERNATE SCENARIOS: CIGS OVER THE LOWLANDS MAY DROP TO IFR WITH
LOW LEVEL MOISTURE THROUGH TODAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY M L L M M M M M L L L L
HTS CONSISTENCY M M L L L M M L L L L L
BKW CONSISTENCY L L M M L L L L L L L L
EKN CONSISTENCY L M M M L L L L L L L L
PKB CONSISTENCY M L L M M M M M L L L L
CKB CONSISTENCY L L L M M M M M L L L L
AFTER 18Z TUESDAY...
IFR IN SNOW SHOWERS POSSIBLE TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR WVZ015-016-
018-024>031-033-034.
WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR WVZ032-
035>040-046-047.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/TAX
NEAR TERM...JSH/TAX
SHORT TERM...RPY
LONG TERM...TRM
AVIATION...TAX
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
400 PM EST Mon Jan 2 2012
...Arctic airmass to arrive tonight and last through Wednesday
morning...
...Freeze warning and wind chill advisory tonight...
.SYNOPSIS...
20Z water vapor and H4 RUC analysis shows a high amplified
northern stream upper level pattern across North America. This
flow consists of high amplitude ridging over the inter-mountain
west...followed downstream by an impressive and still sharpening
trough over the eastern half of the nation. Upstream from our area
we see a strong 140+ knot upper level jet propagating down the
backside of the upper trough. This energy will help to further
amplify the base of the trough into our region during the evening
hours and bring about significant changes to our local weather.
At the surface,
The cold front from Sunday evening is now well south of our area
across the southern FL peninsula. A cooler and drier airmass has
arrived in its wake with temperatures in the 50s, as opposed to
Sunday`s 70s. Winds are also rather gusty with a tight gradient
between the front and a strong 1040+mb surface high building across
the mid-section of the country. The wind advisory remains in effect
for the entire region through the day as efficient diurnal mixing
has allowed stronger winds a few thousand feet aloft to mix down to
the surface. Wind gusts around 25mph have been common across the
region thus far this afternoon.
&&
.SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...
Tonight,
Big changes occur this evening as the upper jet max, and associated
shortwave impulse rotate across the southeastern states. This
impulse will push an secondary arctic cold front quickly across the
forecast area. In the wake of this front, the "flood-gates" in terms
of cold air will open. 850mb temps are progged to plummet 8-10C over
most areas between 00UTC and 06UTC. Temperatures at the surface will
fall below freezing at most area by around 3-4AM and likely remain
below freezing until several hours after sunrise. In fact, often
with these overnight arctic cold frontal passages, we experience the
lowest temperatures a hour or 2 after sunrise, as strong CAA advection
overwhelms any early morning solar addition. Speaking of lows, we
are looking for widespread mid/upper 20s, with upper 20s to around
30 at the immediate coast. Add in a steady NW wind and wind chills
are expected to reach the upper teens in many locations around
sunrise. Due to these expected wind chills, a wind chill advisory
has been issued for all zones late tonight into early Tuesday
morning, in addition to the freeze warning already in effect.
Tuesday/Tuesday Night,
A cold day on tap for the region. Although heights will be rising
through the day as the upper trough exits to our east, this will be
deceiving due to the shallow nature of the arctic airmass in place.
850mb temps which are impressively low around sunrise -6c to -10c
will quickly rebound during the afternoon/evening hours, however the
recovery is much slower below this level leading to a somewhat
inverted thermal profile by the second half of the day. This profile
will hinder efficient diurnal mixing and keep our temps quite cold.
Have once again undercut the MAV as statistical guidance often has
difficulty with these types of airmasses. With some CAA still
ongoing early in the morning and the low sun angle, temperatures
will be very slow to come up during the mid/late morning. We will
eventual recover to chilly readings in the lower 40s north and
perhaps mid 40s south, but with a steady NW wind, wind chills are
likely to remain in the 30s through much (if not all) of the day.
Strong 1030+mb high pressure will quickly build over-top the region
Tuesday evening. This strong high will work with already cold early
evening temps and very dry low level air to produce near ideal
radiational cooling conditions. Expecting temps to fall quite
rapidly in the hour or two around sunset, allowing temps to fall
below freezing early in the night. Temperatures will then remain
below freezing for an extended duration for many locations. The
average time below freezing looks to be around 8-10 hours, however a
few colder spots may see 12+ hours below 32. By sunrise Wednesday
morning, low temps are forecast to reach widespread upper teens to
lower 20s. Would not be surprised to see a few normally colder spots
drop to the middle teens. On the other hand, locations along the
immediate coast and more urbanized inland centers (like downtown
Tallahassee) will see temps bottom out closer to the middle 20s.
Wednesday/Wednesday Night,
The thermal recovery will continue with high pressure remaining
nearby through the day. After the very cold start to the morning,
abundant sunshine should be able to climb our temps back into the
lower 50 by the end of the afternoon. A weak shortwave impulse will
push a subtle cold front toward the region Wednesday night, however
this frontal passage will be little more than a wind shift and some
slightly drier air in its wake. The night will still be cool,
however the thermal ridge ahead of this trough should generally
prevent any widespread freezing temperatures into early Thursday
morning.
&&
.LONG TERM (THURSDAY THROUGH NEXT MONDAY)...
(Wednesday night through next Monday) The evolution of the large
scale upper level pattern across the CONUS will continue to be
dominated by a high persistent latitude negative anomaly just west
of the Dateline, with ridging developing over the eastern Pacific.
Downstream, a mean trough will extending from Canada to the
southwest U.S., with another trough over the western Atlantic. There
is some hint of retrogression in the pattern toward the end of the
period in the 6-10 day guidance, and the latest ECMWF gives some
support to this by dropping a vigorous short wave much further south
and east over the lower Mississippi Valley early next week.
Meanwhile, a series of short waves will move rapidly through the
large scale pattern, and as always the devil is in he details. Will
continue to favor the ECMWF for basic guidance, first of all because
it fits my preconceived ideas, and also because it fits what I think
should be the basic behavior of the short waves, given the larger
scale pattern expected from teleconnections to the anomaly upstream
in the northern Pacific. For the Tri-State Area, this translates to
a fairly rapid moderation in temperatures following one more frosty
morning on Thursday, as heights rise and the cold surface high
weakens and shifts eastward, allowing the low level flow to become
more southerly by the end of the week. Temperatures will return to
near normal on Friday, and above normal through the rest of the
period. An upper level short wave will move rapidly past the area on
Thursday, pushing another rather diffuse and weakening frontal
boundary southward over the Florida Peninsula, while leaving the
boundary stalled over the western Gulf of Mexico. Heights rise
rapidly across the southeast U.S. ahead of a short wave in the
southern stream. This system is forecast to develop a wave along the
front as it moves eastward on Friday and Saturday, and produces
overrunning precipitation across the northern Gulf. The rapid warmup
will preclude a chance for any frozen precipitation. Confidence
remains a bit low on how just how much moisture will be available to
this system, and for now will indicate only slight chance to lower
end chance PoPs, though this could produce a more significant
precipitation event for portions of the northern Gulf and southeast
U.S. Finally, a very impressive short wave in the northern stream is
forecast to dig southward into the lower Mississippi Valley Sunday
and Monday. Keeping in mind the inherent uncertainties present at
such a long time frame, especially given the current fast-moving
progressive pattern, present indicators are that there could be
sufficient return flow ahead of this system, along with good dynamic
support for a potential severe event. Something to keep an eye on
during the coming week.
&&
.AVIATION...
VFR conditions will prevail through the forecast period and beyond.
Reinforcing cold front will push through the region this
evening/overnight, sustaining n-nwly winds with strong afternoon
gusts. This will be a dry front so no vsby or cig restrictions are
expected. LLWS may be a problem for a couple of hours in the
morning if surface winds lighten more than forecast, given the very
strong nly winds just off the surface.
&&
.MARINE...
Northwest wind near advisory levels will increase later this evening
with the passage of a strong cold front. Frequent gusts to gale
force are expected for a period from late this evening into the
early morning hours of Tuesday. These strong winds will result in
very rough seas over the Northeast Gulf of Mexico. Winds and seas
will begin to diminish Tuesday afternoon and Night as strong high
pressure builds over the region.
&&
.FIRE WEATHER...
The coldest air of the season will continue to sink into the region
with very dry conditions and brisk north winds prolonging Red Flag
conditions the rest of today, as well as for our Florida counties
Tuesday. Region will likely see RH in the teens Tuesday with
sustained northerly winds of 15+ mph and higher gusts. These winds
may remain just below criteria in Alabama and Georgia, thus will
maintain a watch across these areas Tuesday afternoon. On
Wednesday, RH will remain in the teens to lower 20s, although winds
will be much lighter and conditions may not support Red Flags with
ERC/dispersions remaining below criteria.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 27 43 18 53 34 / 0 0 0 0 0
Panama City 29 46 28 54 43 / 0 0 0 0 0
Dothan 27 42 24 54 37 / 0 0 0 0 0
Albany 26 42 22 54 33 / 0 0 0 0 0
Valdosta 26 42 21 53 32 / 0 0 0 0 0
Cross City 26 45 18 54 34 / 0 0 0 0 0
Apalachicola 32 46 26 54 41 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Red Flag Warning until 5 PM CST this afternoon for Coffee-Dale-
Geneva-Henry-Houston.
Freeze Warning from Midnight tonight to 8 AM CST Tuesday for
Coffee-Dale-Geneva-Henry-Houston.
Hard Freeze Watch from Tuesday evening through Wednesday morning
for Coffee-Dale-Geneva-Henry-Houston.
Wind Advisory until Midnight CST tonight for Coffee-Dale-Geneva-
Henry-Houston.
Wind Chill Advisory from 3 AM to 9 AM CST Tuesday for Coffee-
Dale-Geneva-Henry-Houston.
Fire Weather Watch Tuesday afternoon for Coffee-Dale-Geneva-
Henry-Houston.
GA...Red Flag Warning until 6 PM EST this evening 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.
Freeze Warning from 1 AM to 9 AM EST Tuesday 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.
Hard Freeze Watch from Tuesday evening through Wednesday 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.
Wind Advisory until 1 AM EST Tuesday 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.
Wind Chill Advisory from 4 AM to 10 AM EST Tuesday 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.
Fire Weather Watch Tuesday afternoon 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...Red Flag Warning until 6 PM EST /5 PM CST/ this evening 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.
Red Flag Warning from 11 AM EST /10 AM CST/ to 6 PM EST /5 PM
CST/ Tuesday 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.
Freeze Warning from 1 AM EST /Midnight CST/ to 9 AM EST /8 AM
CST/ Tuesday 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.
Hard Freeze Watch from Tuesday evening through Wednesday 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.
Wind Advisory until 1 AM EST /Midnight CST/ Tuesday 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.
Wind Chill Advisory from 4 AM EST /3 AM CST/ to 10 AM EST /9 AM
CST/ Tuesday 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 7 PM EST this evening for Apalachee
Bay-Coastal waters From Ochlockonee River to Apalachicola
FL out to 20 NM-Coastal waters from Suwannee River to
Keaton Beach FL out 20 NM-Coastal waters from Apalachicola
to Destin FL out 20 NM-Waters from Suwannee River to
Apalachicola FL from 20 to 60 NM-Waters from Apalachicola
to Destin FL from 20 to 60 NM.
Gale Warning from 7 PM this evening to 8 AM EST Tuesday for
Apalachee Bay-Coastal waters From Ochlockonee River to
Apalachicola FL out to 20 NM-Coastal waters from Suwannee
River to Keaton Beach FL out 20 NM-Coastal waters from
Apalachicola to Destin FL out 20 NM-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...DUVAL
AVIATION/FIRE WEATHER...EVANS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1214 PM EST MON JAN 2 2012
.SYNOPSIS...
ARCTIC HIGH PRESSURE WILL BRING COLD AND DRY CONDITIONS THROUGH MID
WEEK WITH BRISK NORTHWEST WINDS. THE COLDEST TEMPERATURES SINCE LAST
WINTER ARE EXPECTED TUESDAY NIGHT WITH LOWS IN THE TEENS OR LOWER
20S EXPECTED. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH
WEDNESDAY...MODERATING LATE IN THE WEEK AND THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM MONDAY...TEMPERATURES ARE RISING SLOWLY AND THE
TEMPERATURE CURVE IS LEVELING OFF AS MIXING BECOMES INCREASINGLY
DEEP WITH THE COLD ADVECTION ALOFT. TEMPERATURES IN THE 49-52 RANGE
WILL PROBABLY ONLY RISE ANOTHER 1-3 DEGREES THE REMAINDER OF THE DAY
BEFORE PLUMMETING THIS EVENING. THIS IS ALL AS EXPECTED AND NO
SIGNIFICANT CHANGES HAVE BEEN MADE WITH THIS EARLY AFTERNOON
NEAR-TERM UPDATE. PREVIOUS DISCUSSION FROM 930 AM FOLLOWS...
THE FIRST COLD FRONT IS NOW WELL OFFSHORE AND COOLER NORTHWEST WINDS
COVER THE CAROLINAS. THE STRONG NORTHWEST FLOW ACROSS THE MOUNTAINS
HAS SET UP A LEE-SIDE TROUGH EXTENDING FROM ROANOKE TO HICKORY TO
GREENVILLE SC...AND IN RESPONSE A MESOSCALE RIDGE HAS POKED UP
THROUGH THE SC/NC PIEDMONT REGION. THIS EFFECT APPEARS TO BE
WELL-MODELED IN THE LATEST RUC MODEL WHICH SHOWS LIGHTER WINDS THAN
INITIALLY EXPECTED ACROSS THE EASTERN CAROLINAS THIS AFTERNOON. MORE
IMPORTANTLY TO OUR FORECAST...THE 12Z BALLOON SOUNDINGS FROM
MOREHEAD CITY...CHARLESTON SC...AND GREENSBORO SHOWED THE LOWER
ATMOSPHERE UP TO THE 850 MB LAYER AVERAGED 2 DEGREES FAHRENHEIT
WARMER THAN ANY MODEL HAD FORECAST THIS MORNING. WE HAVE RAISED
HIGHS NOT-COINCIDENTALLY BY 2 DEGREES ACROSS THE BOARD TODAY...WITH
MID 50S NOW EXPECTED FOR MOST AREAS.
NO CHANGES ARE EXPECTED FOR TONIGHT. AS STRONG UPPER LEVEL TROUGH
WILL PUSH OFF THE COAST OVERNIGHT WITH TREMENDOUS COLD ADVECTION
DEVELOPING. 850 MB TEMPERATURES WILL FALL FROM AROUND -5C TO -6C
THIS EVENING TO A BONE-CHILLING -13C BY DAYBREAK TUESDAY. A
DEEPLY-MIXED BOUNDARY LAYER WILL BE TOPPED OFF BY SOME HIGH
STRATOCUMULUS/LOW ALTOCUMULUS CLOUDS TONIGHT WHICH HAPPEN TO FORM
RIGHT WITHIN THE -12C TO -18C TEMPERATURES FOR EFFICIENT DENDRITIC
SNOW CRYSTAL GROWTH. A DEEP AND VERY DRY SUBCLOUD LAYER SHOULD BE
ENOUGH TO PREVENT ANY SNOW FLURRIES FROM REACHING THE GROUND OVER
OUR PORTION OF THE CAROLINAS...BUT WE WILL LOOK AGAIN AT THE 12Z
GUIDANCE FOR ANY DISCERNIBLE TRENDS IN BOUNDARY LAYER MOISTURE
CONTENT TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...RAW AND BITTERLY COLD TUESDAY WITH HIGHS IN THE
30S AND WIND CHILLS STUCK IN THE 20S ALL DAY FOR MOST OF THE REGION.
THE REGION WILL BE IN THE THROES OF ARCTIC AIR THROUGH THE
PERIOD...BUT TUESDAY AND TUESDAY NIGHT WILL BRING THE COLDEST OF THE
COLD. FIERCE COLD ADVECTION SHUTS OFF EARLY TUESDAY WITH THE PASSING
OF THE LOW LEVEL THERMAL TROUGH. SAID TROUGH WILL HAVE 850MB TEMPS
BOTTOMED OUT AT AN IMPRESSIVE -13C OR ABOUT 9F. THIS IS COLD ENOUGH
THAT DESPITE A GOOD 6-7KFT OF MIXING HIGH TEMPERATURES WILL STAY IN
THE 30S. GUSTY NW WINDS COULD EASILY REACH 30 MPH AT TIMES KEEPING
THE WIND CHILL NOT ONLY BELOW FREEZING BUT POSSIBLY IN THE 20S ALL
AFTERNOON. SINGLE DIGIT DEWPOINTS PAIRED WITH THE WIND WILL MAKE FOR
SOME FIRE WX CONCERNS AS WELL. TUESDAY NIGHT WILL BE THE COLDEST
PERIOD OF THE ARCTIC INVASION...BUT THERE IS SOME UNCERTAINTY ABOUT
HOW IDEALIZED OF A RADIATIONAL COOLING SETUP IS IN PLACE. GUIDANCE
SUGGESTING THAT THE HIGH MAY BE SUPPRESSED WELL ENOUGH TO THE SOUTH
TO KEEP A FEW MPH OF WIND ALL NIGHT. INDEED FCST SOUNDINGS DO NOT
SHOW THE VERY STEEP SFC BASED INVERSION TYPICAL OF AN ARCTIC RAD
COOLING NIGHT.
WITH THE HIGH OFF TO THE SOUTH THERE IS A SMALL SOUTHERLY COMPONENT
TO THE SURFACE FLOW BY WED. MIXING WILL BE MORE SHALLOW AS COMPARED
TO TUESDAY SO ANY WARMUP WILL BE QUITE GRADUAL. WEDNESDAY HIGHS IN
THE UPPER 40S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...SHARP UPPER TROUGH OVER THE NORTHEASTERN U.S.
WILL BE LIFTING OUT ON THU ALLOWING FOR WEAK HEIGHT RISES OVER
MUCH OF THE EAST WHILE WEAK SFC RIDGE BUILDS IN. THE HIGH PROGRESSES
EAST AND END SUP OFF THE COAST BY FRIDAY NIGHT ALLOWING A RETURN OF
ABOVE CLIMO TEMPS AND SOME MOISTURE ADVECTION. A VERY WEAK SOUTHERN
BRANCH FEATURE NOW STAYS FAR ENOUGH TO OUR SOUTH OVER THE WEEKEND TO
BE OF ANY CONSEQUENCE. A COLD FRONT MAY ENTER AND STALL ACROSS THE
AREA ON SUNDAY...BEING LARGELY LINED UP WITH THE WSW FLOW ALOFT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...VISIBLE SATELLITE LOOPS INDICATE CLEAR SKIES THIS
AFTERNOON ACROSS THE TERMINALS. WITH A VERY DRY AIRMASS IN PLACE
THERE IS HIGH CONFIDENCE OF VFR/CLEAR SKIES THROUGH THE AFTERNOON.
WEST-NORTHWEST TO NORTHWEST WINDS WILL BECOME PROGRESSIVELY MORE
WESTERLY BY LATE AFTERNOON AS SPEEDS DECREASE TO 5-7 KNOTS.
A COLD FRONT WILL MOVE NORTHWEST TO SOUTHEAST ACROSS THE TERMINALS
THIS EVENING. STRONG LIFT IS INDICATED WITH THE FRONT BUT MOISTURE
IS LIMITED. DO NOT EXPECT ANY SIGNIFICANT PRECIPITATION...BUT THERE
SHOULD BE A SHORT PERIOD OF CEILINGS AROUND 6K. THE CHANCE OF ANY
SUB VFR CONDITIONS IS REMOTE ATTM. WINDS WILL SHIFT BACK TO THE
NORTHWEST WITH FROPA AS SKIES CLEAR.
AFTER SUNRISE STRONG COLD AIR ADVECTION AND A TIGHT PRESSURE
GRADIENT WILL PRODUCE NORTHWEST WINDS WITH GUSTS TO 25-30 KNOTS
UNDER VFR/CLEAR SKIES.
NOTE...DUE TO AN ASOS OUTAGE THE KLBT TAF WILL INDICATE AMD NOT SKED
UNTIL OBSERVATIONS ARE AGAIN AVAILABLE ON TUESDAY.
EXTENDED OUTLOOK...VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM MONDAY...WINDS AND SEAS ARE BEHAVING AS EXPECTED. NO
CHANGES WITH THIS NEAR-TERM EARLY AFTERNOON UPDATE. PREVIOUS
DISCUSSION FROM 930 AM FOLLOWS...
THE COLD FRONT IS WELL OFFSHORE AND COOL NORTHWEST WINDS ARE IN
PLACE ACROSS THE COASTAL WATERS. THE COLD FRONT OFFSHORE IS A
PRESSURE TROUGH ITSELF...AND THERE IS A LEE-SIDE TROUGH OF LOW
PRESSURE IN THE NC/SC FOOTHILLS AS WELL. BETWEEN THESE TWO SYSTEMS A
SMALL-SCALE RIDGE OF RELATIVE HIGH PRESSURE HAS DEVELOPED ACROSS THE
NC/SC PIEDMONT REGION. WINDS ARE LIGHTER NEAR THIS RIDGE...AND THIS
SHOULD HELP INSULATE THE REGION FROM ANY STRONGER WIND SPEEDS UNTIL
TONIGHT. NORTHWEST WINDS IN THE 15-20 KT RANGE THIS MORNING WILL
COME DOWN MORE INTO THE 15 KT RANGE THIS AFTERNOON...BUT INCREASING
RAPIDLY THIS EVENING AS A STRONG UPPER LEVEL DISTURBANCE SHOOTS OFF
THE COAST AND TREMENDOUSLY COLD AIR BEGINS TO POUR OFF THE COAST AND
OVER THE COASTAL WATERS. THIS IS WHEN WINDS COULD INCREASE TO GALE
FORCE FOR SEVERAL HOURS.
SEAS RANGE FROM 2-4 FT ACROSS THE COASTAL WATERS THIS MORNING WITH
LITTLE CHANGE EXPECTED THROUGH THE DAY. SEAS WILL REALLY INCREASE
TONIGHT ESPECIALLY FOR LOCATIONS GREATER THAN 5-10 MILES FROM THE
COAST DUE TO INCREASING EFFECTIVE FETCH LENGTH WITH THE NORTHWEST
WINDS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...STRONG GRADIENT AND DEEP MIXING CAUSED BY
EXTREME COLD/STEEP LAPSE RATES WILL SPONSOR STRONG WINDS FOR MOST OF
THE PERIOD. THIS WILL BE MOST PREVALENT ON TUESDAY WHEN THE COLD AIR
AND GRADIENT WILL BE AT THEIR STRONGEST. GUSTS TO GALE FORCE TOUGH
TO RULE OUT BUT CURRENT WRF FORECAST CAPS 850MB FLOW AT 30KT. THE
SURFACE GRADIENT AND GUSTINESS RELATED TO THE LOW LEVEL JETTING WILL
BOTH DECREASE TUESDAY NIGHT AS HIGH PRESSURE BUILDS INTO FLORIDA AND
NE GOMEX...FLAGS WILL BE ABLE TO BE LOWERED. THIS HIGH NOW GETS
QUICKLY SUPPRESSED TO THE SOUTH BY WED AFTERNOON BRINGING LIGHT
WINDS THAT WILL BACK TO SWRLY.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...A MODERATE OFFSHORE/NW GRADIENT WIND REMAINS IN
PLACE EARLY THURSDAY BUT A QUICK ABATEMENT TO AROUND 10KT BY
AFTERNOON IS EXPECTED AS HIGH PRESSURE SETTLES ACROSS FL AND NE
GOMEX. AS THE ANTICYCLONE PROGRESSES EAST AND ENDS UP NE OF BAHAMAS
BY FRIDAY WIND LOCALLY BACKS TO SW WHILE SPEEDS REMAIN FAIRLY
CONSTANT. SEAS COMPRISED OF MAINLY SHORT PERIOD WIND WAVES AND WILL
AVG 2 TO 3 OR 2 TO 4 FT THROUGH THE PERIOD.
&&
.FIRE WEATHER...
THE DRIEST AIR OF THE SEASON WILL CONTINUE TO MOVE INTO THE AREA
TODAY AND PERSIST INTO MID WEEK. THIS DRY AIR COUPLED WITH GUSTY NW
WINDS MAY SERVE TO INCREASE THE FIRE DANGER ACROSS THE AREA. THE
WORST OF THESE CONDITIONS ARE EXPECTED ON TUESDAY. MINIMUM RELATIVE
HUMIDITY WILL BE NEAR OR BELOW CRITICAL VALUES AND WINDS WILL BE
CLOSE TO THRESHOLD AS WELL...MAINLY IN GUSTS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WARNING FROM 6 PM THIS EVENING TO 7 AM EST TUESDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...MRR
FIRE WEATHER...RJD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1225 PM EST MON JAN 2 2012
.SYNOPSIS...
STRONG UPPER LEVEL LOW AND ARCTIC AIRMASS RESULTS IN WIND BLOWN SNOW
SHOWERS THROUGH TUESDAY. WEAKER COLD FRONT MOVES THROUGH WEDNESDAY.
DRY WITH MODERATING TEMPERATURES FOR THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST RADAR MOSAIC SHOWS AREAS OF SNOW...SOME HEAVY...MOVING EAST
ACROSS THE FORECAST AREA. RADAR INDICATES A FEW MESOSCALE FEATURES
IN THE FLOW...WITH SOME OF THE HEAVIER SNOW BEING PRODUCED BY THESE
FEATURES.
UPPER LEVEL FEATURE...WHICH IS STILL LOCATED NORTHWEST OF REGION...
IS EXPECTED TO APPROACH THE AREA LATER TODAY. THIS SHOULD FURTHER
ENHANCE THE SNOW.
CURRENT FORECAST IS PRETTY MUCH ON TRACK. HOWEVER...WILL TAKE A LOOK AT
SNOWFALL FORECAST TO SEE IF WE MIGHT NEED TO BUMP IT UP IN A FEW
LOCATIONS FOR TODAY.
PREVIOUS DISCUSSION...
IR SATELLITE IMAGERY SHOWING MID AND LOW LEVEL CLOUD DECK
APPROACHING WESTERN FLANKS. A RIDGE OF LOW H85 MOISTURE WAS
EVIDENT AHEAD OF THIS CLOUD DECK...WHICH LED TO CLEARING OVER
CENTRAL PORTIONS OF CWA. THIS SHOULD FILL IN QUICKLY OVER NEXT
SEVERAL HOURS.
RUC H85 MOISTURE ACCURATELY DEPICTING MOISTURE ASSOCIATED WITH LOW
AND MID LEVEL CLOUDS STREAMING DOWNSTREAM OF THE GREAT LAKES. CURRENT H85
TEMPS FROM RUC ARE ABOUT -9C. WITH RUC H925 TEMPS ABOUT -3C...LAPSE
RATES ARE STEEPENING AND SHOULD CONTINUE WITH ADDITIONAL CAA. STEEP
LAPSE RATES AND ADDED DEEP MOISTURE WILL ONLY ADD TO THE SPATIAL
COVERAGE OF SNOW SHOWERS ALREADY DEVELOPING NW INTO CENTRAL OHIO.
KEPT SNOW TOTALS CLOSE TO PREVIOUS FORECAST...BUT DID TWEAK EKN
VICINITY UP A BIT AS THAT AREA RECEIVED A QUICK 1.5 INCHES OF NEW
SNOW BEFORE MIDNIGHT...THIS SNOW COMING BEFORE THE REAL MOISTURE
ARRIVES. PLAN TO KEEP ADVISORIES THE SAME AS PREVIOUS FORECAST.
BELIEVE OUR NW WV COUNTIES COULD COME CLOSE TO MEETING ADVISORY
CRITERIA FOR SNOW TOTALS IN 12HR TIME FRAME...BUT WOULD LIKE TO SEE
TRENDS IN INITIAL SNOW DEVELOPMENT FIRST.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
COLD AIR ADVECTION CONTINUES INTO TUESDAY AFTERNOON. MODELS SHOWING
LAKE PLUMES ALSO EFFECTING THE AREA...ALTHOUGH DEEPER MOISTURE PULLS
OUT IN THE MORNING. SHOULD BE PLENTY OF SNOW FLAKES AROUND...BUT
ACCUMULATIONS SHOULD BE LIMITED...WITH THE BEST ACCUMULATIONS IN THE
LAKE PLUMES. WARM AIR ADVECTION THEN SETS IN FOR TUESDAY NIGHT...AND
SHOULD BRING AN END TO THE SNOW.
ANOTHER MUCH WEAKER SYSTEM SKIRTS NORTHERN PORTIONS OF THE REGION ON
WEDNESDAY AND WEDNESDAY NIGHT. COULD SEE SOME LIGHT SNOW IN THE
NORTHERN COUNTIES...BUT THIS SYSTEM IS FAIRLY MOISTURE STARVED...SO
WILL KEEP POPS LOW.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
ONE LAST UPPER LEVEL S/W TROF MOVES SE THROUGH THE AREA IN THE
LARGER SCALE NW FLOW ALOFT RIGHT AT THE START OF THE PERIOD.
UPSLOPE FLOW IN ITS WAKE SHOULD BRING LIGHT SNOW SHOWERS OR
FLURRIES TO THE MOUNTAINS WED NT INTO THU MORNING. WITH HEIGHTS
QUICKLY LIFTING THU...EXPECT THE AIR MASS IN THE WAKE OF THE FRONT
TO NOT BE QUITE AS COLD AS ITS PREDECESSOR...AND THE UPSLOPE EVENT
NO WHERE NEAR THE DURATION OR MAGNITUDE OF ITS PREDECESSOR.
HIGH PRESSURE CROSSES THU NT...FOLLOWED BY SW FLOW ON ITS BACK SIDE
FRI INTO THE WEEKEND. NEXT NORTHERN STREAM UPPER LEVEL S/W TROUGH
DRIVES SURFACE COLD FRONT THROUGH THE AREA OVER THE WEEKEND...WITH
MODEL DIFFERENCES ON TIMING. MOISTURE GETS DRAWN UP AHEAD OF THE
FRONT INTO THE FORECAST AREA JUST AS THE FRONT APPROACHES SAT
MORNING. AIR MASS BEHIND FRONT DOES NOT IT LEAST INITIALLY APPEAR
TO BE AS COLD AS THE ONE CHARGING THROUGH EARLY THIS WEEK.
UPPER LOW FORMS OVER THE SWRN CONUS EARLY IN THE WEEKEND IN RESPONSE
TO RIDGING OFF THE W COAST. MODELS THEN START TO EJECT THIS LOW
NEWD LATE IN THE WEEKEND WITH SOME TIMING DIFFERENCES IN TANDEM WITH
SIMILAR DIFFERENCES IN THE NORTHERN STREAM.
BLENDED IN MEX / HPC FOR TEMPERATURES...NO SIGNIFICANT CHANGES.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
LOW LEVEL MOISTURE PLUME CONTINUES TO MOVE SOUTHEAST ACROSS OUR
AREA. RADAR AND SATELLITE IMAGERY SHOWS SEVERAL MID-LEVEL TROFS
PUSHING ACROSS AREA...WITH THE MAIN SHORTWAVE OVER INDIANA.
IN RESPONSE TO MOISTURE AND FEATURES...SCATTERED SNOW SHOWERS WITH
MVFR...ISOLD IFR...CONDITIONS WERE BEING REPORTED. VFR CONDITIONS
PREVAILED OUTSIDE OF THE SNOW.
THE MAIN WAVE IS EXPECTED TO PUSH SOUTHEAST ACROSS AREA BETWEEN
21Z AND 06Z TUESDAY. AS THIS FEATURE PUSHES ACROSS AREA...EXPECT
CONDITIONS ACROSS THE LOWLANDS WILL DETERIORATE TO MVFR...ISOLD IFR
IN SNOW SHOWERS BY 22Z...WITH IFR...ISOLD LIFR...CONDITIONS IN
THE MOUNTAINS. THESE CONDITIONS ARE EXPECTED TO CONTINUE THROUGH
15Z...WITH CONDITIONS EXPECTED TO SLOWLY IMPROVE AFTER THAT TIME.
EXPECT GUSTY WESTERLY WINDS WILL SLOWLY DECREASE THRU 01Z...WITH
GUSTY WINDS CONTINUING ACROSS THE HIGHER ELEVATIONS UNTIL 12Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE:MODERATE.
ALTERNATE SCENARIOS: DRY AIR IN THE LOWER LEVELS COULD ACT TO HOLD
VFR/MVFR CONDITIONS FOR A LONGER PERIOD OF TIME...BEFORE
DETERIORATING LATER TODAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY L L L M L L M L L L L L
HTS CONSISTENCY L M M M M M L M M M M M
BKW CONSISTENCY M M L L L L L L L L L L
EKN CONSISTENCY M M L L L L M L L L L L
PKB CONSISTENCY L M M M M L L M L L L L
CKB CONSISTENCY L L M M L L L L L L L L
AFTER 18Z TUESDAY...
IFR IN WIDELY SCATTERED MOUNTAIN SNOW SHOWERS POSSIBLE EARLY
TUESDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR WVZ015-016-
018-024>031-033-034.
WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR WVZ032-
035>040-046-047.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/TAX
NEAR TERM...JSH/TAX
SHORT TERM...RPY
LONG TERM...TRM
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS SPOKANE WA
244 PM PST Mon Jan 2 2012
.SYNOPSIS...A weak cold front will pass through the Inland
Northwest tonight bringing a good chance of light rain and
snow...to most locations north of I90. After this front passes
through the weather will turn drier for most locations through
Wednesday. Through the end of the workweek and into the
weekend...a series of relatively weak weather disturbances will
deliver a decent chance of valley rain and light mountain snow
accumulations every 24 to 36 hours.
&&
.DISCUSSION...
Tonight...Compact upper level low and associated occluded front
will provide to focus for the weather tonight across the Inland
Northwest. As of 2pm...the upper level low was just off the
Olympic Peninsula with the frontal occlusion extending south-
southeast toward the Portland area. The low was being picked up
fairly well by the short-range models...however the NAM solution
was a bit too far to the south whereas the ECMWF and RUC were
faring much better. Both these solutions take the core of the
upper level cold pool and shortwave trough into extreme southeast
BC by 06z and into southern Saskatchewan by 12z. The occluded
front will track along with the upper level and spread
precipitation across the northern half of the forecast area. We
expect the Cascades will sap some of the moisture as it tracks
into the western Columbia Basin early this evening but it will
regain its continuity as it moves into northeast Washington and
north Idaho late this evening. Precipitation chances look very
good as strong isentropic ascent develops north of a Coulee Dam to
Sandpoint line. This lifting will also tap into the deep
instability through the dendritic layer associated with the cold
core upper level shortwave trough. The weather type over these
areas will undoubtedly fall as snow with wet-bulb temperatures
well below zero through the entire lower atmosphere. Most of the
northern valleys in Washington into north Idaho will see snowfall
amounts ranging from 0.5-1.5 inches with 1-3" totals probable
across the Methow and upper Wenatchee Valleys.
Where the forecast becomes more dicey is over the northern
Columbia Basin from Wenatchee to Spokane. Precipitation in this
region is far from certain and anything which does fall should be
fairly light. The big question is what will it fall as. We suspect
closer to the Cascades it will fall as all snow...but over Lincoln
and Spokane County...model consistency is poor. Some solutions
suggest a snow level near 4000 feet while others have it near the
ground. Based on the latest surface observations we will lean
toward the lower numbers...but even so we don`t expect to see much
in the way of accumulation. Precipitation chances over SE
Washington into the central Panhandle look quite small.
Precipitation chances will gradually taper off over most areas
overnight as the upper level trough and occluded front track well
east of the region. The exception will occur near the Cascade
crest and Idaho Panhandle mountains where moist and somewhat
unstable flow will continue to produce some residual showers. fx
Tuesday through Thursday...The progressive weather pattern will
continue across the region with a mainly dry day expected Tuesday
before the next weather system in the conga line brings rain and
mountain snow to the Inland Northwest by mid-week.
As warm air advection starts to take place in the mid levels,
there may be pockets of freezing rain in the northern Cascade
valleys Tuesday night but the more likely scenario would be wet
snow. By Wednesday the advancing warm front will tap into a
subtropical fetch of moisture with twice the normal precipitable
water levels. Warm air advection will strengthen Wednesday, pushing
snow levels well above all valley floors during the day. Decent
isentropic lift into the northeast mountains and Idaho Panhandle
Wednesday night will combine with orographic ascent to enhance
precipitation across the northeast zones.
The cold front will sweep through the forecast area Thursday.
Models continue to show weaker surface pressure gradients than
previous solutions with this frontal zone. Conditions should be
breezy to windy with the cold frontal passage. We should see some
strong gusts but they will probably remain just below advisory
criteria.
Storm total precipitation is in the range of 1 to 2 tenths in the
lower valleys with a quarter inch to 4 tenths for the valleys across
the northern half of the forecast area. The mountains (other than
the Blues) could see a half to three quarters of an inch of liquid
from the mid week system. The high mountains could see some
significant snowfall during this event. The only area of concern
will be the east slope Cascade valleys like the Methow where cold
air will be difficult to scrub out. They could see a few inches of
accumulation Tuesday night into Wednesday before snow levels rise.
By the time colder air moves in behind the cold front Thursday,
QPF will be much lighter and in the form of scattered showers, with
only very light accumulations expected in the valleys, if any at
all. Temperatures will be on a warming trend Tuesday and Wednesday,
then cool behind the cold front Thursday. /Kelch
Thursday night through Monday: Upper level ridge starts to push
inland Thursday night as the cold front exits north Idaho. A
drying trend is expected Thur night and Friday as the ridge
shifts over the inland northwest. The exception to this is across
the mountains where a light shower is possible. The flow remains
fairly progressive with a weak feature moving through Friday night
in northwest flow ahead of another ridge. Right now models aren`t
showing anything impressive with this wave, it looks to impact
mostly extreme eastern WA and north ID with no exciting amounts of
snowfall. From Saturday afternoon through Monday it looks like the
ridge dominates with all weather systems going north into British
Columbia. By Monday I did trend a bit toward climatology given
some uncertainty with the GFS hinting at a trough possibly moving
into the area. The big change in the extended forecast was to
start trending chance of precipitation down. Took mention of
showers out of the valleys and low lying areas and kept slight
chance to chance in the mountains. Temperatures are expected to be
around average for this time of the year. /Nisbet
&&
.AVIATION...
18z TAFs...The first portion of this aviation forecast will be easy
with VFR conditions expected to prevail at all sites. As we get
into the tonight and Tuesday morning portion of the forecast (Aft
00z) things become much more difficult...at least for the northern
sites due to the approach of the upper level low and frontal
occlusion. Precip type will provide the main challenge as temps
will be precariously close to freezing at the onset of the event.
At EAT...there is no guarantee that any precip will fall...but if
it does...there are better chances of snow than rain. At
KGEG...KSFF...and KCOE...its a much tougher call as the model
solutions are evenly split between rain and snow. We will lean
toward the warmer NAM solution since it better matches the current
obs and this would suggest rain. If the precip falls primarily as
rain we will see a mix of VFR vsbys and VFR/MVFR cigs...however
if its primarily snow we could see more IFR conditions than
forecast. We will adjust as the event draws near. LWS and PUW will
generally escape any chance of precipitation. More uncertainty
exists in the late periods of the forecast as there are hints of
IFR/LIFR stratus forming over the Basin late tonight. We will go
with that notion for now...but if the precip during the evening is
underwhelming...the low clouds won`t develop as expected. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 28 39 31 44 34 40 / 40 0 10 20 40 30
Coeur d`Alene 30 42 31 46 32 43 / 50 10 10 20 40 60
Pullman 33 46 34 49 35 43 / 20 0 0 10 30 50
Lewiston 34 48 37 51 39 49 / 10 0 0 0 30 40
Colville 26 40 31 42 31 40 / 70 20 20 30 60 60
Sandpoint 30 39 32 43 33 38 / 60 20 20 30 60 70
Kellogg 30 40 31 44 32 40 / 60 10 20 20 50 70
Moses Lake 26 42 30 46 34 43 / 10 0 10 10 40 10
Wenatchee 28 40 30 40 33 39 / 20 10 10 20 50 10
Omak 23 38 30 39 31 38 / 40 10 20 30 50 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
257 PM CST MON JAN 2 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY
257 PM CST MON JAN 2 2012
MAIN FORECAST CONCERNS ARE CLOUD COVER AND TEMPERATURES...ALONG WITH
WHETHER PRECIPITATION CAN OCCUR TUESDAY NIGHT.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED A SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST...RIDGING FROM
THE SOUTHWEST U.S. NORTHWARD INTO SASKATCHEWAN...AND DEEP TROUGHING
FROM SOUTHEAST CANADA SOUTHWARD INTO THE SOUTHEAST U.S.. COLD AIR
ASSOCIATED WITH THIS DEEP TROUGH IS FIRMLY ENTRENCHED OVER THE
FORECAST AREA...WITH 850MB TEMPS PER 12Z RAOBS AROUND -18C. GRB
SOUNDING REFLECTS THE COLD ADVECTION SEEN AS WELL...NOTED BY 24 HOUR
TEMPERATURE DROP OF 10-15C FROM THE SURFACE TO 400MB. TROPOPAUSE HAS
ALSO BEEN LOWERED TO 425MB. CLOUD COVER...RELATED TO MOISTURE STUCK
BELOW THE COLD FRONTAL INVERSION NEAR 800MB PER 12Z GRB/MPX
SOUNDINGS...HAS BEEN SLOWLY DISSIPATING DUE TO A COMBINATION OF
DAYTIME MIXING AND DRY AIR ADVECTING SOUTH OUT OF NORTHERN ONTARIO.
TO THE WEST...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE EASTERN
DAKOTAS. FURTHER WEST...WARM ADVECTION IS TAKING PLACE ALONG THE LEE
OF THE ROCKIES...NOTED BY 12Z SOUNDINGS FROM GGW AND UNR WITH 850MB
TEMPS AROUND 0C. CIRRUS HAS BEEN PRESENT IN THESE AREAS TOO...COMING
FROM PACIFIC MOISTURE TOPPING THE UPPER RIDGING THERE.
TONIGHT AND TUESDAY...UPPER RIDGE SEEN OVER MONTANA INTO
SASKATCHEWAN IS PROGGED TO PUSH EAST DURING THIS PERIOD...IN
RESPONSE TO THE SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST MOVING
INTO WESTERN MINNESOTA BY 00Z WEDNESDAY. THE UPPER RIDGE AXIS SHOULD
CROSS THE FORECAST AREA MID-DAY TUESDAY. WITH THE UPPER RIDGING
BUILDING IN PROVIDING PLENTY OF SUBSIDENCE...NO PRECIPITATION IS
ANTICIPATED. EVEN AFTER THE UPPER RIDGE PASSES LATE TUESDAY AND
500MB HEIGHTS BEGIN TO FALL...THE PRESENCE OF SO MUCH DRY AIR
BROUGHT IN BY THE CURRENT UPPER TROUGH WILL KEEP THINGS DRY AND ANY
WARM ADVECTION CLOUDS TO MID OR HIGH LEVEL. CONCERN TONIGHT IS HOW
LOW TEMPERATURES MAY END UP WITH CLEAR SKIES LIKELY AND THE SURFACE
RIDGE MOVING IN OVERNIGHT. WOULD NOT BE SURPRISED IF TYPICAL COLD
SITES NORTH OF I-94...WHERE MORE THAN A TRACE OF SNOW EXISTS ON THE
GROUND...DROP TO 5 TO 10 BELOW ZERO. MOST OF THE REST OF THE AREA
SHOULD SEE LOWS IN THE SINGLE DIGITS ABOVE ZERO...WITH OTHER TYPICAL
COLD SPOTS IN WISCONSIN DROPPING TO 0 TO 5 BELOW. INCREASING SOUTH
WINDS WILL BRING IN WARMER AIR FOR TUESDAY...CAUSING 850MB TEMPS TO
CLIMB TO -2 TO -6C BY 18Z. SOME OF THIS WARM AIR MAY BE CAPPED
OFF...HELPED TOO BY THE INCREASE IN MID AND HIGH CLOUDS LATER IN THE
DAY PREVENTING MIXING. THEREFORE...HIGHS ARE ONLY FORECAST IN THE
20S. A FEW SITES IN NORTHEAST IOWA COULD TOP 30...THOUGH...CLOSER TO
THE WARMEST AIR MOVING IN AND BEING SNOW-FREE.
TUESDAY NIGHT THROUGH THURSDAY...SHORTWAVE TROUGH OVER WESTERN
MINNESOTA IS WELL AGREED UPON TO MOVE SOUTHEAST ACROSS THE FORECAST
AREA TUESDAY NIGHT...WITH 500MB HEIGHTS SLOWLY BUILDING IN ITS WAKE
THROUGH THURSDAY. THE RISING HEIGHTS ARE IN RESPONSE TO A SHORTWAVE
TROUGH MOVING INTO BRITISH COLUMBIA AND THE PACIFIC NORTHWEST...
PUSHING RIDGING THAT DEVELOPED AHEAD OF IT EASTWARD. REGARDING
TUESDAY NIGHTS SHORTWAVE TROUGH...NOT IMPRESSED FOR PRECIPITATION.
ALTHOUGH DPVA FORCING IS PRETTY DECENT GIVEN THE TRACK...ISENTROPIC
LIFT IS VERY WEAK AT BEST AND MOSTLY CONFINED NORTH AND EAST OF OUR
FORECAST AREA. IN ADDITION...MOISTURE IS SERIOUSLY LACKING BETWEEN
850-650MB WHICH SHOULD BE ABLE TO ABSORB MOST OF THE SNOW BEING
PRODUCED ALOFT. WITH THE 02.12Z NAM/GFS/ECMWF ALL DRY...HAVE PULLED
PRECIPITATION CHANCES FOR TUESDAY EVENING...BUT DID LEAVE A MENTION
OF FLURRIES IN CASE ANYTHING CAN REACH THE GROUND. AFTER THIS...ONLY
ISSUES BECOME CLOUDS/TEMPERATURES WITH NO SYSTEMS EXPECTED TO COME
THROUGH TO PRODUCE PRECIPITATION. LOOKS LIKE THERE MAYBE SOME LOW
STRATUS IN THE WAKE OF THE TROUGH TUESDAY NIGHT...MAINLY OVER
WISCONSIN...WHICH SHOULD CLEAR OUT BY 12Z WEDNESDAY. OTHER BATCHES
OF MID/HIGH CLOUD ARE POSSIBLE LATE WEDNESDAY INTO THURSDAY
MORNING...MOSTLY ALONG AND EAST OF THE MISSISSIPPI RIVER...INDUCED
BY THE WARM ADVECTION PATTERN SET UP BY THE RISING 500MB HEIGHTS.
THEREFORE...WHEN IT COMES TO TEMPERATURES...BEST MIXING IS LIKELY TO
OCCUR WEST OF THE MISSISSIPPI RIVER. BIGGEST PROBLEM WHEN IT COMES
TO TEMPERATURES IS SEEING THE WARM ADVECTION AND HOW MUCH OF IT CAN
MIX DOWN. 850MB TEMPS CLIMB TO -2 TO +2C BY 00Z THURSDAY AND 7-11C
BY 00Z FRIDAY. WINDS ARE NOT FORECAST TO BE THAT STRONG...5 TO MAYBE
15 KT AT BEST WHICH HURTS MIXING...THOUGH THEY ARE OUT OF THE WEST
TO SOUTHWEST WHICH IS A GOOD DIRECTION. CERTAINLY SNOW FREE AREAS
COULD GET QUITE WARM FOR THIS TIME OF YEAR. FOR NOW HAVE FOLLOWED A
BLEND OF GUIDANCE FOR TEMPERATURES THROUGH THE TUESDAY NIGHT THROUGH
THURSDAY TIME PERIOD...BUT RAISED THEM UP A FEW DEGREES FOR HIGHS
OVER SNOW-FREE AREAS WEST OF THE MISSISSIPPI RIVER. NOTE...
THURSDAYS RECORD HIGH IS 47 AT LA CROSSE AND 45 AT ROCHESTER. THERE
IS POTENTIAL TO GET CLOSE TO THIS...ESPECIALLY IF WE ARE SUNNY ALL
DAY.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
257 PM CST MON JAN 2 2012
02.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ARE IN PRETTY GOOD
AGREEMENT AGAIN TODAY ON THE UPPER LEVEL AND SURFACE PATTERNS
HEADING INTO THE WEEKEND...AND REPRESENT SOLUTIONS SIMILAR TO THOSE
SEEN YESTERDAY. GENERAL THEME IS FOR THE WESTERN RIDGING SEEN
RECENTLY TO BRIEFLY BREAK DOWN AS A SHORTWAVE COMING OFF THE PACIFIC
DIGS DOWN TOWARDS THE FOUR CORNERS REGION ON SATURDAY. MEANWHILE...
DOWNSTREAM...THE SHORTWAVE TROUGH THAT WAS IN BRITISH COLUMBIA ON
THURSDAY IS FORECAST TO CROSS THE AREA FRIDAY NIGHT...PLACING THE
AREA IN TROUGHING FOR THE WEEKEND. NEW RIDGING IS THEN FORECAST TO
BUILD OVER THE WESTERN U.S. INTO THE NORTHERN PLAINS FOR SUNDAY
NIGHT INTO MONDAY...WHILE SHORTWAVES STREAM SOUTHEAST TOWARDS THE
UPPER GREAT LAKES ON THE EDGE OF THIS RIDGING.
OVERALL UPPER PATTERN IS UNFAVORABLE FOR MUCH IF ANY PRECIPITATION
AS MOISTURE IS VERY LIMITED. ANY MOISTURE IS TRAPPED BY THAT THE
SHORTWAVE DROPPING INTO THE FOUR CORNERS REGION...WHICH LOOKS TO
CROSS THE GULF COAST SUNDAY INTO MONDAY IN ADDITION...THERE
APPEARS TO BE A LACK OF SYSTEMS WITH MUCH FORCING. THEREFORE...A
DRY FORECAST CONTINUES THROUGH MONDAY.
TEMPERATURES REMAIN THE BIGGEST PROBLEM...ESPECIALLY GIVEN THE
UN-CLIMATOLOGICAL LACK OF SNOW ON THE GROUND OVER A LOT OF THE UPPER
MIDWEST. A COLD FRONT ASSOCIATED WITH THE SHORTWAVE TROUGH CROSSING
THE AREA FRIDAY NIGHT IS PROGGED TO MOVE THROUGH THE AREA FRIDAY
MORNING. ALTHOUGH 850MB TEMPS FALL THROUGH THE DAY...FROM 6-10C AT
12Z FRIDAY TO -2 TO +2C BY 00Z SATURDAY...THIS COOLING COMBINED WITH
MORE WIND COULD RESULT IN BETTER MIXING THAN THURSDAY. PLUS...WE
WILL START OFF WARMER ON FRIDAY. THEREFORE...FRIDAY SHOULD END UP
JUST AS WARM AS THURSDAY IF NOT WARMER. COOL DOWN THEN CONTINUES
INTO THE WEEKEND AS TROUGHING MOVES OVERHEAD...NOTED BY 850MB TEMPS
FALLING TO -5 TO -10C BY 00Z SUNDAY AND -7 TO -10C BY 00Z MONDAY.
THE COOL DOWN IS BRIEF...AS THE NEXT WARM UP ENSUES FOR MONDAY WITH
THE HEIGHT RISES ALOFT. FOR SATURDAY THROUGH MONDAY...FOLLOWED A
BLEND OF GUIDANCE FOR HIGHS AND LOWS.
&&
.AVIATION...THROUGH 18Z TUESDAY
1127 AM CST MON JAN 2 2012
HIGH PRESSURE WILL BUILD INTO THE AREA THIS AFTERNOON INTO THIS
EVENING WITH SKIES GRADUALLY CLEARING AT THE TAF SITES. PLAN ON
VFR CONDITIONS THROUGH THE FORECAST PERIOD. LOOK FOR NORTHWEST
WINDS OF 15 TO 30 KTS LATE THIS AFTERNOON...BECOMING LIGHT AND
VARIABLE OVERNIGHT. THE HIGH WILL SLIDE EAST OF THE AREA TUESDAY
MORNING AS A TROUGH APPROACHES FROM THE DAKOTAS. WINDS WILL SWITCH
TO THE SOUTH BY LATE TUESDAY MORNING. PLAN ON SOUTH WINDS AT 12 TO
20 KTS...WITH GUSTS TO AROUND 27 KTS BY TUESDAY AFTERNOON. HIGH
CLOUDS WILL BE ON THE INCREASE TUESDAY MORNING AS THE TROUGH
APPROACHES THE REGION...WITH CLOUD BASES IN THE 15 KFT TO 20 KFT
RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
257 PM CST MON JAN 2 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
221 PM CST MON JAN 2 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW CYCLONIC FLOW
CONTINUING UNABATED OVER THE GREAT LAKES THIS AFTERNOON...WHILE HIGH
PRESSURE IS GRADUALLY SHIFTING EAST OVER THE GREAT PLAINS. PLENTY
OF LOW LEVEL MOISTURE...STEEP LOW LEVEL LAPSE RATES...AND MOISTURE
FLUXES OFF LAKE SUPERIOR ARE CONTRIBUTING TO SCATTERED FLURRIES AND
LIGHT SNOW SHOWERS OUTSIDE OF THE LAKE EFFECT SNOW BELT. SPEAKING
OF WHICH...1-3SM VISIBILITIES (WITH POCKETS OF LOWER VSBYS) IN SNOW
SHOWERS HAVE BEEN PREVAILING WITHIN THE SNOW BELT FOR MUCH OF THE
DAY. DRY AIR AS NOTED ON SATELLITE IMAGERY WITH DEWPOINTS SUB-ZERO
HAVE BEEN ERODING THE STREAMERS OVER WESTERN LAKE SUPERIOR AND ARE
STARTING TO APPROACH THE U.P. SHORELINE. WINDS HAVE BEEN THE
BREEZIEST OVER DOOR COUNTY WHERE HAVE SEEN A FEW GUSTS AROUND 39 KTS
AT SISTER BAY AND 35 KTS BY ALGOMA. WINTER WEATHER AND WIND
HEADLINES ARE THE MAIN FORECAST CONCERN IN THE SHORT TERM.
TONIGHT...SURFACE HIGH PRESSURE OVER THE GREAT PLAINS WILL SHIFT
EAST TO THE WESTERN GREAT LAKES BY MORNING. AS THE RIDGE AXIS
APPROACHES FROM THE WEST...STRONG MID-LEVEL SUBSIDENCE AND LOW LEVEL
DRY AIR BROUGHT IN BY NORTH WINDS WILL SHUT DOWN THE LAKE EFFECT
PROCESSES OVER WESTERN LAKE SUPERIOR...WHICH WILL CUT OFF THE
MOISTURE TRANSPORT FARTHER SOUTH AND EAST. AS A RESULT...WILL SEE
CLEARING SKIES THIS EVENING EVEN OVER THE SNOW BELT WHERE LAKE
EFFECT STREAMERS WILL BECOME INCREASINGLY CONFINED TO THE U.P.
BORDER. WILL LEAVE A SCATTERED MENTION OF SNOW SHOWERS THROUGH
MID-EVENING. WILL WAIT UNTIL THE LAST MINUTE TO DECIDE PULL THE
WINTER STORM WARNING...AS IT DEPENDS ON VISIBILITIES AND THE DEGREE
OF EROSION OF THE LAKE EFFECT BANDS FROM THE DRY AIR. WIND
HEADLINES ARE ALSO PROBLEMATIC AS ONLY THE TIP OF THE DOOR HAS BEEN
APPROACHING WIND ADVISORY CRITERIA. WINDS SHOULD ONLY GRADUALLY
SUBSIDE THIS EVENING...SO ALSO THINK MAY BE ABLE TO PULL THE
ADVISORY HEADLINE AT PRESS ISSUANCE. ANOTHER LAST MINUTE DECISION
ON THAT ONE. WINDS WILL BE DECOUPLING OVER CENTRAL AND NORTHERN
WISCONSIN AFTER MIDNIGHT. WITH THE FRESH SNOW PACK...TEMPS SHOULD
PLUMMET LATE TO SOME OF THE COLDEST READINGS OF THE SEASON. BUT
BECAUSE WINDS WILL BE DECOUPLING...WIND CHILL READINGS WILL ONLY
FALL TO 20 BELOW...WHICH FALLS JUST SHORT OF HEADLINES.
TUESDAY...SURFACE HIGH PRESSURE WILL MOVE EAST OF THE AREA BY MIDDAY
IN RESPONSE TO SHORTWAVE ENERGY TRACKING OVER THE NORTHERN PLAINS
AND NORTHERN MISSISSIPPI VALLEY. WILL SEE MID AND HIGH CLOUDS MOVE
OVERHEAD DOWNSTREAM OF THE SHORTWAVE...BUT LOW LEVELS ARE WAY TO DRY
FOR PRECIP. AFTER A COLD START TO THE DAY...HIGH TEMPS WILL REBOUND
TO THE MID TEENS TO LOW 20S.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. NEXT SYSTEM TO
AFFECT THE FORECAST AREA TOWARD TUESDAY NIGHT MAKING LANDFALL ON
THE NORTHWEST US COAST TODAY. TREND OF THE LAST FEW MODEL RUNS
WITH THIS SYSTEM HAVE BEEN DRY DUE TO LIMITED MOISTURE WHILE
WORKING OVER THE ROCKIES...AND MOVING AT GOOD CLIP IN THE FAST
NORTHWEST FLOW. THIS FAIRLY DEEP SHARP WAVE TROUGH WITH SURFACE
TROUGH REFLECTION HAS A NICE PERIOD OF WAA TUESDAY NIGHT...BUT
AVAILABLE LIFT AND MOISTURE WILL MAINLY SERVE TO SATURATE THE AIR
MASS...AND THE BEST SNOW GROWTH REGION PASSES QUICKLY OVER. DUE TO
CONSISTENT MODEL TO MODEL GUIDANCE OF NO MEASUREABLE QPF...WILL
LOWER POPS BUT KEEP A NON MEASURABLE PCPN MENTION GOING.
FOR THE REMAINDER OF THE WORK WEEK...THE WESTERN STATES UPPER
RIDGE FLATTENS WHILE A SYSTEM PASSES OVER SOUTHERN CANADA. A
PERIOD OF WAA WILL RAISE TEMPS ABOVE NORMAL LEVELS THIS WEEK UNTIL
A COLD FRONT DROPS OVER LATE IN THE WEEK FOR A RETURN TO MORE
NORMAL TEMPERATURES. NORTHWEST FLOW PROVIDES A MINOR LES SNOW
CHANCE FOR THE FAR NORTH CENTRAL WISCONSIN FRIDAY NIGHT INTO
SATURDAY.
ANOTHER NORTHERN STREAM SHORT WAVE TROUGH WITH FRONTAL SYSTEM
BRUSHES THE NORTHERN GREAT LAKES REGION TOWARD MONDAY...OTHERWISE
THE MEDIUM RANGE MODELS INDICATE NO SIGNIFICANT SYSTEMS TO AFFECT
THE AREA THROUGH EARLY NEXT WEEK.
&&
.AVIATION...ONGOING LAKE EFFECT SNOW SHOWERS WILL BE DIMINISHING
THIS AFTERNOON...WHICH WILL RESULT IN IMPROVING CONDITIONS AT RHI.
STILL WILL HAVE A COUPLE HOURS OF POSSIBLE MVFR CIGS/VSBYS IN SNOW
SHOWERS THOUGH. OTHERWISE...THE REST OF THE TAF SITES WILL DEAL
WITH SCT/BKN LOW END VFR CIGS WITH A FEW FLURRIES FOR THE REST OF
THE AFTERNOON. DRY AIR FROM CANADA WILL WORK ACROSS THE REGION LATE
THIS AFTERNOON THROUGH THE EVENING...THAT WILL LEAD TO CLEARING
CONDITIONS AND DIMINISHING WIND SPEEDS. WILL HAVE INCREASING MID
AND HIGH CLOUDS TOMORROW MORNING...BUT VFR CONDITIONS WILL PREVAIL
FROM EARLY THIS EVENING ONWARD.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TDH