Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/10/12
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
320 AM EST Wed Feb 8 2012
.SYNOPSIS...
07Z water vapor and H4 RUC analysis continues to show a rather
complex upper level pattern across the CONUS this morning. REX block
configuration from 24 hours ago over the western portion of the
continent has broken down, with the closed upper low over Colorado
now having opened up and become progressive. This trough and any
significant associated forcing will pass north of our region today.
We continue to see an active southern stream flow with abundant
mid/upper level energy in the form of high level cirrus streaming
northward over the Gulf of Mexico.
At the surface, forecast area resides in a region of weak gradient
between 1035mb high pressure over the central Plains, and a surface
trough in place across the southern FL Peninsula/FL Straits.
Weak/subtle cold front is analyzed slowly approaching our area
across AL. This front is better defined above the surface, but
should at least result in a somewhat drier low level airmass in its
wake over the next couple of days. Regional radars do show a few
showers up into central AL/Northern GA in closer proximity to the
passing synoptic forcing. However as mentioned above, this
sufficient forcing will remain to our north and keep shower chances
out of our forecast.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
Today,
Mid/Upper level shortwave passes from the TN valley this morning to
the mid-Atlantic coast this evening. Atmospheric momentum associated
with this energy will be enough to pass a weak cold frontal boundary
through the forecast area by mid/late afternoon. This will be an
uneventful frontal passage with only some clouds and a slight wind
shift to mark its arrival. Overall, will be a pleasant February day
with filtered sunshine and high temperatures ranging from the upper
60s north to the lower 70s south.
Tonight,
Dry and somewhat cooler night upcoming to what has been experienced
lately. The drier airmass will allow temperatures to fall into the
upper 30s to lower 40s for much of the area. The high center will
still be well to our NW keeping the gradient fairly tight. With this
in mind, don`t anticipate much chance of any normally sheltered
areas de-coupling and getting much colder than is currently
forecast. Therefore, temperatures and dewpoint depressions should
stay above the level of a frost threat.
Thursday/Thursday night,
Little change in the forecast with any significant northern stream
energy remaining well to our north. High level clouds will likely be
on the increase once again by the end of the day as southern stream
jet energy re-develops along the northern Gulf Coast. Plenty of dry
air in the lower levels will keep rain out of our forecast with high
temps reaching up into the 60s. Surface ridging will set up just to
our north Thursday night which will bring the potential for some mid
30s temps inland, and a resulting frost potential. However, some
uncertainly remains regarding the amount of mid/high level clouds
that will be overspreading the area. Impressive southern stream jet
energy suggest we will see the cirrus. Even high level cloudiness
can sometimes disrupt the radiative process and help keep temps
warmer than expected. This portion of the forecast will need to be
monitored closely for those with sensitive outdoor vegetation.
Friday,
Uncertainly is beginning to increase by the end of Friday with
regards to energy propagating across the southern Plains and
northern Gulf coast. GFS is showing a scenario in which much of this
energy is absorbed by a large cut-off low near the California Baja
region. ECMWF/Canadian are much more aggressive, and allow the
majority of this shortwave energy to bypass the upper low into the
southern Plains. These models offer solutions that are potentially
wetter for our western zones by Friday evening, and for all of our
zones Friday night. Tough call on this one, but out of respect for
the ECMWF will add slight chance PoPs to the grids beginning Friday
afternoon in the far west, and for all zones Friday night. Should
the ECMWF/Canadian solution be the correct trend, then these rain
chances would need to be adjusted upward in future forecast
packages.
&&
.LONG TERM (SATURDAY THROUGH NEXT WEDNESDAY)...
The complex and generally messy large scale pattern is expected to
remain so during the forecast period, while undergoing some
retrogression, with axis of the mean ridge over the western U.S.
shifting westward into the eastern Pacific, and the large polar
vortex over eastern Canada also evolving westward. The main effect
will be to broaden the mean trough westward across the CONUS,
resulting in a positive tilted trough axis across the Intermountain
West, and a nearly zonal flow eastward across the eastern half of
the country. The southern portion of the stream will remain quite
strong. A series of short waves will drop southward into the mean
trough axis over the Intermountain West, then weaken as they head
rapidly east or northeast across the eastern U.S. As always, the
devil is in the details when it comes to the forecast for he
Tri-State Area. The GFS and Euro continue to diverge predictably
towards the end of the period, in how they handle the short waves
dropping into the mean trough position. The Canadian and EURO are in
better agreement, showing more short wave energy in the southern
stream, which gives me some confidence, and a blend of the two
solutions seems the way to go. Friday night and Saturday short wave
energy will be moving eastward across the eastern U.S. pushing a
cold front well to the south across the southern Florida peninsula,
bringing at least a slight chance of rain, and a surge of colder
drier air behind it across the southeast U.S. Temperatures may drop
to near or a little below freezing in some areas on Monday morning.
Then expect a fairly rapid rebound in temperatures by mid week,
along with an increasing chance of rain, as the next short wave
rounds the bottom of the trough and heads northeast. Temperatures
will start out near normal on Saturday, then drop below normal
Sunday and Monday, then trend back to above normal by Wednesday.
&&
.MARINE
A weak cold front will cross the forecast area today. The gradient
behind this front will increase and result in near advisory level
northerly winds tonight through Thursday morning. A surface ridge
will slowly build down from the north later Thursday into Friday
which will act to drop winds and seas back down below headline
criteria. Another period of cautionary to advisory level northerly
flow looks to develop during the upcoming weekend.
&&
.AVIATION (THROUGH 06Z THURSDAY)...
VFR conditions will continue across the Tri-State Area through the
forecast period and beyond, with patches of cirrus occasionally
streaming across the area. Although a drier airmass has spread into
the region, good nighttime cooling will result in temperatures
dropping to near the dew point temperatures in some areas, allowing
for the formation of some mist before daybreak. The mist, in
combination with some lingering smoke, will produce patches of MVFR
visibilities primarily across south central Georgia before sunrise.
&&
.FIRE WEATHER...
Drier air is spreading across the Tri-State Area, and relative
humidities across inland portions of Florida will drop to at or
below 35 percent for several hours this afternoon, along with
relatively high dispersions. However, dispersions are not expected
to be quite high enough to warrant a Red Flag Watch or Warning, and
ERC values will continue relatively low. Thursday will remain dry,
with longer periods of critical relative humidity values, while
dispersions are expected to be a little lower. However, ERC values
are currently expected to remain below critical levels, so while
conditions for Thursday afternoon should be closely monitored, there
are no fire weather concerns at this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 72 39 66 36 70 / 0 0 0 0 10
Panama City 71 44 64 42 65 / 0 0 0 0 10
Dothan 68 40 62 38 66 / 0 0 0 0 10
Albany 69 38 63 35 67 / 0 0 0 0 10
Valdosta 71 39 65 39 70 / 0 0 0 0 10
Cross City 75 39 69 40 73 / 0 0 0 0 10
Apalachicola 70 42 64 41 65 / 0 0 0 0 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...DUVAL
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1027 PM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE SOUTHEAST STATES THROUGH
FRIDAY WHILE A TROUGH OF LOW PRESSURE DEVELOPS OVER THE NEARBY
COASTAL WATERS. A COLD FRONT WILL THEN PUSH THROUGH FRIDAY NIGHT
INTO SATURDAY BEHIND DEPARTING LOW PRESSURE WITH A REINFORCING
COLD FRONT SATURDAY NIGHT. COLD HIGH PRESSURE WILL THEN BUILD BACK
INTO THE REGION AND PERSIST THROUGH EARLY NEXT WEEK. ANOTHER STORM
SYSTEM MAY AFFECT THE AREA BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
MID/HIGH LEVEL CLOUDS OF VARYING THICKNESS WILL CONTINUE TO
STREAM ACROSS THE REGION OVERNIGHT. MEANWHILE...00Z NAM GUIDANCE
CONTINUES TO DEPICT INCREASING LOW LEVEL MOISTURE TRANSPORT/
SHALLOW ISENTROPIC ASCENT SPREADING INTO SOUTHERN/COASTAL COUNTIES
OVERNIGHT. HOWEVER...THE NAM HAS BACKED OFF ON TIMING OF
SPOTTY/LIGHT SHOWERS ACROSS SOUTHERN COASTAL WATERS/FAR SOUTHERN
COASTAL COUNTIES UNTIL 09Z-12Z...AND THE LATEST RUC SUGGESTS
PRECIPITATION WILL DEVELOP EVEN A FEW HOURS LATER. THUS...DELAYED
ONSET OF SLIGHT CHANCE/CHANCE POPS ACROSS SOUTHERN COASTAL
COUNTIES/ADJACENT COASTAL WATERS UNTIL LATE TONIGHT.
LOW CLOUDS COULD PRODUCE A WIDE TEMPERATURE RANGE ACROSS THE
REGION OVERNIGHT. WHERE LOW CLOUDS BECOME WIDESPREAD...MOST
LIKELY ACROSS COASTAL AND SOUTHERN COUNTIES...TEMPERATURES COULD
BEGIN TO RISE LATE TONIGHT AND WIDESPREAD 40S/LOWER 50S COULD BE
COMMON BY DAYBREAK. WELL INLAND...WHERE LOW CLOUDS WILL LIKELY NOT
ARRIVE UNTIL AFTER DAYBREAK...A FEW LOCATIONS WILL BOTTOM OUT
CLOSE TO FREEZING.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
MODEL SOLUTIONS ARE IN RELATIVELY GOOD AGREEMENT THROUGH THE SHORT
TERM PERIODS...RESULTING IN NEAR TO SLIGHTLY ABOVE NORMAL FORECAST
CONFIDENCE. THE BIGGEST FORECAST CHALLENGE IS THE RAIN POTENTIAL
FRIDAY AND FRIDAY NIGHT AS A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NEARBY ATLANTIC WATERS AND PUSHES TOWARD THE COAST WHILE LOW
PRESSURE DEVELOPS TO THE SOUTH AND MOVES NORTHEAST BY THE AREA.
THERE SHOULD BE SUFFICIENT MOISTURE AND LIFT TO PRODUCE SOME LIGHT
SHOWERS...MAINLY NEAR THE COAST AND THIS IS WHERE WE WILL HIGHLIGHT
THE BEST RAIN CHANCES FOR LAND AREAS. RAINFALL SHOULD END BY
DAYBREAK SATURDAY WITH COLD ADVECTION TO ENSUE DURING THE DAY WHICH
WILL AT FIRST BE OFFSET TO SOME EXTENT BY THE BREEZY WEST/NORTHWEST
DOWNSLOPE FLOW. A REINFORCING COLD FRONT WILL THEN PUSH THROUGH
SATURDAY NIGHT AS A 150+ KT UPPER JET PUSHES OFFSHORE ALLOWING
ARCTIC HIGH PRESSURE TO MOVE IN FROM THE WEST WHICH WILL PERSIST
THROUGH SUNDAY.
TEMPERATURES WILL DROP DRAMATICALLY SATURDAY NIGHT AND STRONG COLD
ADVECTION WILL PUSH TEMPERATURES INTO THE MID TO UPPER 20S MOST
AREAS...LIKELY EVEN REACHING BELOW FREEZING AT THE IMMEDIATE COAST.
THUS...THOSE WITH SENSITIVE VEGETATION OUTDOORS WILL WANT TO TAKE
THE PROPER PRECAUTION TO PROTECT THEM. SINCE OUR FROST/FREEZE
PROGRAM HAS YET TO OFFICIALLY BEGIN...WE DO NOT PLAN TO ISSUE ANY
FROST ADVISORIES OR FREEZE WATCHES/WARNINGS. WILL CONTINUE TO
HIGHLIGHT THE COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND
CONSIDER ISSUING SPECIAL WEATHER STATEMENTS AS WE GET CLOSER TO THE
EVENT. SINCE WINDS WILL REMAIN IN THE 10-20 MPH RANGE THROUGH THE
NIGHT...WIND CHILLS WILL MAKE IT FEEL EVEN COLDER...IN THE MID TO
UPPER TEENS. HIGHS ON SUNDAY WILL STRUGGLE TO REACH 50 DEGREES AFTER
A VERY COLD START.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN MORESO
BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE WIND ADVISORY
WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH SUNDAY MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AFTER A BRIEF BREAK FROM THE MODEL DISCONTINUITY...OPERATIONAL
SOLUTIONS ARE ONCE AGAIN DISPLAYING POOR AGREEMENT FOR THE MIDDLE
AND LATTER PORTIONS OF THE LONG TERM PERIOD. GUIDANCE IS IN GOOD
AGREEMENT EARLY IN THE PERIOD...SHOWING HIGH PRESSURE BUILDING OVER
THE REGION SUNDAY NIGHT AND MONDAY BEFORE BUILDING EASTWARD AND INTO
THE WESTERN ATLANTIC MONDAY NIGHT. SOLUTIONS THEN DEVIATE ON THE
POSITIONING AND PROGRESSION OF SYNOPTIC DETAILS TUESDAY THROUGH
THURSDAY...LEADING TO LOWER THAN NORMAL FORECAST CONFIDENCE. GIVEN
THE UNCERTAINTY IN THE TUESDAY THROUGH THURSDAY TIME FRAME...WILL
TRY TO CAPITALIZE ON PERIODS WHERE THE MODELS ARE MORE CLOSELY
ALIGNED WHILE TRYING TO MINIMIZE POTENTIAL FORECAST ERROR WHERE THE
MODEL SOLUTIONS DIVERGE MORE SIGNIFICANTLY.
AS FOR FORECAST DETAILS...WILL KEEP THE FORECAST RAIN FREE SUNDAY
NIGHT THROUGH MONDAY NIGHT WITH HIGH PRESSURE REMAINING THE DOMINANT
WEATHER FEATURE. DESPITE THE MODEL DIFFERENCES IN POSITIONING AND
PROGRESSION OF SYNOPTIC DETAILS BEGINNING ON TUESDAY...THEY DO AGREE
ON BRINGING DEEPER MOISTURE ALONG WITH A SURFACE FRONTAL BOUNDARY
INTO THE REGION...SO WILL CARRY SLIGHT CHANCE POPS TUESDAY AND
TUESDAY NIGHT. THE OPERATIONAL SOLUTIONS THEN DEVIATE MORE
NOTICEABLY WEDNESDAY THROUGH THURSDAY. FOR NOW...WILL ADVERTISE RAIN
FREE CONDITIONS WEDNESDAY THROUGH THURSDAY AS THE MODEL SOLUTIONS
GENERALLY SHOW THE DEEPEST MOISTURE SHIFTING OUT OF THE REGION AND
HOLDING OFF ON A RETURN OF ANY SIGNIFICANT MOISTURE RETURN THROUGH
THURSDAY NIGHT. OBVIOUSLY...THIS PORTION OF THE FORECAST IS QUITE
UNCERTAIN...SO CHANGES IN FORECAST THINKING ARE VERY POSSIBLE OVER
THE NEXT SEVERAL DAYS.
TEMPERATURES IN THE BEGINNING OF THE LONG TERM PERIODS WILL START
OUT WELL BELOW CLIMATOLOGY SUNDAY NIGHT AND MONDAY...WITH LOWS IN
THE 20S MOST LOCALES AND HIGHS IN THE MID TO UPPER 50S. TEMPERATURES
WILL MODERATE ON TUESDAY...WITH HIGHS CLOSE TO SEASONAL LEVELS IN
THE LOW TO MID 60S. TEMPERATURES WILL CONTINUE TO WARM DURING THE
MID TO LATE WEEK TIME FRAME TO ABOVE NORMAL LEVELS...WITH HIGHS
GENERALLY IN THE UPPER 60S TO LOWER 70S.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
VFR THIS EVENING. OVERNIGHT...MODELS CONTINUE TO PUSH LOW LEVEL
MOISTURE ONSHORE...INITIALLY INTO SOUTHERN COUNTIES THEN SPREADING
NORTH...AND LOW CLOUD CEILINGS SHOULD DEVELOP OVERNIGHT. SREF GUIDANCE
SUGGESTS AT LEAST A 70 PERCENT CHANCE FOR MVFR CEILINGS AT KSAV BY
18Z FRIDAY...FOLLOWED BY SUBTLE LOW LEVEL DRYING/IMPROVEMENT TO
VFR LEVEL CEILINGS PRIOR TO 00Z. AT KCHS...SREF GUIDANCE ALSO
INDICATES A HIGH PROBABILITY FOR MVFR CEILINGS BY 21Z FRIDAY.
SINCE MODEL SOUNDINGS SUPPORT THIS SCENARIO...INTRODUCED A PERIOD
OF MVFR CEILINGS AT BOTH TERMINALS FRIDAY AFTERNOON. GIVEN 00Z
NAM TRENDS...MVFR CEILINGS COULD DEVELOP EARLIER...AND A PERIOD OF
IFR CEILINGS CANNOT BE RULED OUT.
MEANWHILE...ISENTROPIC ASCENT AND UPPER LEVEL DIVERGENCE SUPPORTED
BY AN INTENSIFYING JET AXIS SHOULD SUPPORT AT LEAST SOME LIGHT
PRECIPITATION...THUS INTRODUCED A MENTION OF SHOWERS WITH VFR
VISIBILITY. 00Z NAM GUIDANCE CONTINUES TO INDICATE HIGH POPS AND
MVFR VISIBILITY IN SHOWERS...WILL CONTINUE TO ASSESS THIS
SCENARIO.
EXTENDED AVIATION OUTLOOK...MVFR CIGS AND/OR VSBYS COULD AFFECT THE
TERMINALS THROUGH FRIDAY NIGHT AS A WAVE OF LOW PRESSURE LIFTS BY
WELL OFF THE COAST OF THE SOUTHEAST UNITED STATES. MVFR CONDITIONS
COULD IMPACT THE TERMINALS ONCE AGAIN ON TUESDAY AS ANOTHER STORM
SYSTEM MOVES THROUGH THE AREA. IN ADDITION...GUSTY WINDS WILL
IMPACT THE TERMS SATURDAY WITH LLWS POSSIBLE SATURDAY NIGHT.
&&
.MARINE...
OVERNIGHT...WEAK SURFACE TROUGHING SHOULD MAINTAIN E/NE WINDS...
WITH LITTLE EVIDENCE TO SUPPORT THE 00Z NAM FORECAST OF SE WINDS.
WINDS WILL REMAIN 15 KT OR LESS. SEAS WILL RANGE FROM 2-3 FT
WITHIN NEARSHORE WATERS TO 3-4 FT BEYOND 20 NM.
FRIDAY THROUGH TUESDAY...A WAVE OF LOW PRESSURE WILL DEVELOP OFF THE
SOUTHEAST COAST ON FRIDAY AND PUSH NORTHEASTWARD AND AWAY FROM THE
AREA FRIDAY NIGHT AS A COLD FRONT PUSHES THROUGH THE MARINE AREA. A
REINFORCING COLD FRONT WILL THEN MOVE THROUGH THE WATERS ON
SATURDAY...FOLLOWED BY HIGH PRESSURE THROUGH EARLY NEXT WEEK.
ANOTHER STORM SYSTEM MAY AFFECT THE AREA BY NEXT TUESDAY.
WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS FRIDAY
BUT WINDS COULD REACH ADVISORY RANGE FRIDAY NIGHT AS THE PRESSURE
GRADIENT TIGHTENS AND LOW-LEVEL WINDS/COLD ADVECTION STRENGTHEN
BEHIND THE DEPARTING AREA OF LOW PRESSURE. ALL WATERS ARE EXPECTED
TO SEE ADVISORY CONDITIONS BY SATURDAY NIGHT AS A REINFORCING COLD
FRONT MOVES THROUGH. GALE FORCE GUSTS ARE ALSO POSSIBLE...MAINLY
BEYOND 20 NM. SLOWLY IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY AS
THE COLD AIR ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO
WEAKEN. AT THIS TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW
ADVISORY LEVELS ACROSS THE NEARSHORE WATERS BY NOON ON
SUNDAY...WITH SEAS MOST LIKELY REMAINING AT OR ABOVE SMALL CRAFT
THRESHOLDS ACROSS THE OUTER GEORGIA WATERS THROUGH LATE SUNDAY
AFTERNOON OR EARLY SUNDAY EVENING. CONDITIONS WILL CONTINUE TO
IMPROVE SUNDAY NIGHT THROUGH MONDAY NIGHT...THEN POSSIBLY GO
DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE SYSTEM POSSIBLY TRACKS
THROUGH THE AREA.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
226 PM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NONE.
KJB
//DISCUSSION...UPDATED 18Z...
SKIES ARE IN THE PROCESS OF CLEARING ACROSS NORTHEASTERN ILLINOIS
AND NORTHWESTERN INDIANA LATE THIS MORNING. ONCE SKIES DO
CLEAR...THEY SHOULD REMAIN SO FOR THE REMAINED OF THE PERIOD.
SURFACE HIGH PRESSURE WILL DOMINATE ACROSS THE MID MISSISSIPPI
VALLEY THROUGH MUCH OF THURSDAY. THIS WILL CONTINUE TO SET UP WEST
TO SOUTHWESTERLY SURFACE FLOW ACROSS THE AREA. NO WEATHER CONCERNS
ARE EXPECTED IN THE NEXT 36 HOURS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE ON ALL FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY/SATURDAY...CHC LAKE EFFECT SNOW WITH MVFR/IFR POSSIBLE.
SUNDAY/MONDAY...VFR.
TUESDAY...SLT CHC RAIN/SNOW.
BMD
&&
.MARINE...
225 PM CST
THE CONCERNS WITH THE MARINE FORECAST MAINLY CENTER ON THE POTENTIAL
GALE FORCE WINDS ON FRIDAY WITH THE PASSAGE OF AN ARCTIC FRONT. IN
THE MEANTIME...A RIDGE OF HIGH PRESSURE OVER THE SOUTHERN LAKES WILL
GRADUALLY SLIDE SOUTH THROUGH TONIGHT AND INTO THURSDAY. WINDS AND
WAVES SHOULD STAY FAIRLY STEADY IN THAT TIME. LOW PRESSURE WILL MOVE
SOUTHEAST ACROSS ONTARIO ON THURSDAY NIGHT AND SWING A STRONG COLD
FRONT SOUTH ACROSS LAKE MICHIGAN ON FRIDAY. IMMEDIATELY AFTER THIS
PASSAGE...A PERIOD OF NORTHERLY GALE FORCE GUSTS LOOK LIKELY AT THIS
TIME...INCLUDING POTENTIALLY ALONG THE INDIANA NEAR SHORE. SOME
SCATTERED FREEZING SPRAY APPEARS POSSIBLE OVER THE LAKE GIVEN THE
DEGREE OF COLD AIR FORECAST...PRIMARILY OVER THE NORTHERN PORTION.
IN ADDITION...SOME PROLONGED LAKE EFFECT SNOW IS LIKELY ACROSS THE
FAR SOUTHERN PART OF THE LAKE. WINDS WILL BE VERY SLOW TO DIMINISH
AND WAVES JUST AS STUBBORN TO SUBSIDE THROUGH FRIDAY NIGHT AND
SATURDAY.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...6 AM FRIDAY TO
MIDNIGHT SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
156 PM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NONE.
KJB
//DISCUSSION...UPDATED 18Z...
SKIES ARE IN THE PROCESS OF CLEARING ACROSS NORTHEASTERN ILLINOIS
AND NORTHWESTERN INDIANA LATE THIS MORNING. ONCE SKIES DO
CLEAR...THEY SHOULD REMAIN SO FOR THE REMAINED OF THE PERIOD.
SURFACE HIGH PRESSURE WILL DOMINATE ACROSS THE MID MISSISSIPPI
VALLEY THROUGH MUCH OF THURSDAY. THIS WILL CONTINUE TO SET UP WEST
TO SOUTHWESTERLY SURFACE FLOW ACROSS THE AREA. NO WEATHER CONCERNS
ARE EXPECTED IN THE NEXT 36 HOURS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE ON ALL FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY/SATURDAY...CHC LAKE EFFECT SNOW WITH MVFR/IFR POSSIBLE.
SUNDAY/MONDAY...VFR.
TUESDAY...SLT CHC RAIN/SNOW.
BMD
&&
.MARINE...
315 AM CST
FOLLOWING THE PASSAGE OF A COLD FRONT AND WITH HIGH PRESSURE
BUILDING ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
VALLEY...WINDS WILL GRADUALLY DIMINISH. AS THE HIGH PRESSURE SAGS
TO THE SOUTHEAST WEDNESDAY AND THURSDAY...WINDS WILL BECOME
WESTERLY TO 25KT AND EVENTUALLY SOUTHWESTERLY...AS ANOTHER ARCTIC
COLD FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE LAKE
THURSDAY NIGHT. A STRONG PUSH OF COLD AIR MAY BRING WINDS UP TO
GALE FORCE OVER THE FAR NORTHERN PORTIONS OF THE LAKE LATE
THURSDAY INTO THURSDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1156 AM CST WED FEB 8 2012
.DISCUSSION...
ISSUED 915 AM CST WED FEB 8 2012
WILL BE UPDATING THE FORECAST SHORTLY TO ADJUST THE MORNING PERIOD
WITH LIGHT SNOW AND FLURRIES OVER EASTERN IL WITH LITTLE OR NO
ADDITIONAL ACCUMULATIONS EXPECTED. ALSO ADJUSTING THE SKY COVER
TODAY WITH SLOWING CLEARING DOWN A BIT FROM THE NORTH. HIGHS 32 TO
38F LOOK ON TRACK WITH MILDEST READINGS IN SE IL.
FAIRLY STRONG UPPER LEVEL TROF OVER THE MIDWEST INCLUDING IL HAD A
LARGE AREA OF LOW CLOUDS OVER MUCH OF MO/IL/IN AND SE IA. THERE
WAS A CLEAR SLOT OVER NW IL AS FAR SOUTH AS PEORIA. AREA OF VERY
LIGHT SNOW AND FLURRIES WAS FROM BLOOMINGTON/NORMAL NE AND
DRIFTING SE TOWARD CHAMPAIGN/URBANA. TEMPS RANGED FROM THE UPPER
20S OVER CENTRAL IL NW OF I-70...TO THE MID 30S IN SE IL FROM
ROBINSON TO FLORA SE. NW WINDS 7 TO 13 MPH WAS USHERING IN DRIER
AIR WITH DEWPOINTS RANGING FROM THE UPPER TEENS AND LOWER 20S NW
OF I-55 TO THE UPPER 20S TO NEAR 30F FROM DANVILLE TO TAYLORVILLE
SE.
HI-RESOLUTION 12Z HRRR MODEL ACTUALLY SHOWS POCKETS OF VERY LIGHT
SNOW SHOWERS AND FLURRIES LINGERING OVER CENTRAL IL THROUGH THE
DAY. 12Z NAM...SREF AND RUC MODELS SHOW BRUN OF THE LIGHT SNOW
EAST OF IL TODAY WITH LIGHT POCKETS OF QPF OVER EAST CENTRAL IL
THIS MORNING WHICH BETTER SUPPORTS RADAR TENDS AND LEANED IN THIS
DIRECTION. DID SLOW CLEARING OF THE LOW CLOUDS FROM THE NORTH TODAY
WITH LOW CLOUDS LINGERING MUCH OF TODAY OVER SE IL. 1035 MB HIGH
PRESSURE OVER EASTERN NEBRASKA WILL SETTLE INTO THE MID MS VALLEY
BY THU MORNING HELPING CLEAR THE REST OF THE LOW CLOUDS TONIGHT
AND BRINGING SEASONABLY COLD TEMPS TODAY AND TONIGHT. NW WINDS 7
TO 13 MPH TODAY TO BECOME LIGHT WEST DURING TONIGHT AS HIGH
PRESSURE SETTLES IN.
HUETTL
&&
.AVIATION...
ISSUED 1155 AM CST WED FEB 8 2012
VFR CEILINGS OF 3-5K FT WILL OCCUR THIS AFTERNOON AND THEN
SCATTERED OUT DURING THIS EVENING FROM NW TO SE. THERE WILL STILL
BE SOME MFVR CEILINGS FROM 1.2-3K FT FROM BMI AND DEC EAST TO CMI
UNTIL MID AFTERNOON WITH FLURRIES STILL NEAR CMI NEXT HOUR OR SO.
MVFR VISIBILITIES POSSIBLE LATE TONIGHT/EARLY THU MORNING WITH
LIGHT FOG WITH CLEAR SKIES AND LIGHT WINDS. MVFR CEILINGS TO
SPREAD BACK EAST INTO THE MS VALLEY LATE THU MORNING FROM 15Z-18Z
AND LIKELY TO SPREAD EAST ACROSS PIA AND SPI AND TO HIGHWAY 51 BY
BMI AND DEC BETWEEN 18Z-21Z THU JUST AFTER THE 24 HOUR TAF PERIOD.
NW WINDS AROUND 10 KTS THIS AFTERNOON TO DIMINISH LIGHT THIS
EVENING AND BE W/SW 7-11 KTS FROM MID THU MORNING ON.
FAIRLY STRONG UPPER LEVEL TROF OVER THE GREAT LAKES REGION AND
OHIO VALLEY INCLUDING IL WILL KEEP A FAIR AMOUNT OF LOW CLOUDS
AROUND THIS AFTERNOON WHICH EXTEND UPSTREAM INTO SE IOWA. EVEN
THE DRY SLOT AROUND PIA IS FILLING BACK IN WITH BROKEN CUMULUS
CLOUDS AT MIDDAY. USED THE 925-850 MB RH FIELD FROM THE HI-RES
MODELS TO TIME CLEARING/SCATTERING OUT OF LOW CLOUDS FROM NW TO SE
DURING THIS EVENING. 1035 MB HIGH PRESSURE OVER THE CENTRAL PLAINS
OVER EASTERN NEBRASKA/KS WILL SETTLE INTO THE MID MS VALLEY THU
MORNING. A SHORT WAVE NEAR THE MT/SD BORDER WILL RACE ESE TOWARD
THE IL/MO/IA BORDER LATE THU MORNING SPREADING LOW CLOUDS BACK
EAST TOWARD THE MS VALLEY AND COULD APPROACH PIA AND SPI BY
18Z/NOON THU.
HUETTL
&&
.PREV DISCUSSION...
ISSUED 250 AM CST WED FEB 8 2012
THE SHORTWAVE MOVING ACROSS THE CENTRAL U.S. WAS CROSSING ILLINOIS
EARLY THIS MORNING...PER WATER VAPOR IMAGERY. AREA OF LIGHT
SNOW...WHICH HAD PRODUCED A DUSTING...HAD LARGELY TAPERED IN
AREAS NORTH OF I-72. DID HAVE SOME LIGHT FREEZING DRIZZLE MIXED IN
EARLY ON AROUND PEORIA AND GALESBURG.
PRIMARY FORECAST ISSUES FOR THIS PACKAGE INVOLVE THE COLD AIR FOR
THIS WEEKEND...AS WELL AS PRECIPITATION CHANCES BEGINNING ON MONDAY.
SHORT TERM...TODAY THROUGH SATURDAY...
HIGH RESOLUTION MODELS STILL SHOWING LIGHT SNOW LINGERING OVER
THE EASTERN CWA EARLY THIS MORNING. REGIONAL RADAR LOOPS SHOWING
SOME PRECIPITATION STILL PRESENT AS FAR NORTH AS THE I-80
CORRIDOR IN NORTHEAST ILLINOIS...MOVING SOUTHWARD...SO THIS
SCENARIO SEEMS PLAUSIBLE. WILL KEEP 30-50 PERCENT POPS GOING EAST
OF I-57 EARLY THIS MORNING BEFORE TAPERING TO FLURRIES.
OTHERWISE...A QUIET PERIOD IS EXPECTED FROM LATE THIS AFTERNOON
THROUGH THURSDAY...AS HIGH PRESSURE DRIFTS SOUTHEAST INTO THE
TENNESSEE VALLEY.
THE COLD SNAP WHICH HAS BEEN ADVERTISED FOR THE LAST SEVERAL DAYS
IS STILL ON TRACK. 00Z MODELS IN GOOD AGREEMENT IN SWEEPING A COLD
FRONT ACROSS THE FORECAST AREA ON FRIDAY. THE FAR SOUTHEAST MAY
STAY IN THE WARMER AIR LONG ENOUGH TO REACH WELL INTO THE 40S...
BUT TEMPERATURES ELSEWHERE IN THE AFTERNOON WILL BE STEADY OR
FALLING. HAVE LOWERED TEMPERATURES FRIDAY NIGHT AND SATURDAY BY A
FEW MORE DEGREES FROM THE EARLIER VALUES. SOME OF THE GUIDANCE
SUGGESTS EVEN COLDER READINGS...BUT LACK OF SNOW COVER MAY HINDER
THAT THOUGHT. THE FRONT ITSELF IS LARGELY EXPECTED TO COME THROUGH
DRY IN OUR AREA...AND WILL ONLY GO WITH 20 POPS ACROSS THE EAST ON
FRIDAY MORNING.
LONG TERM...SUNDAY THROUGH TUESDAY...
TEMPERATURES ON SUNDAY EXPECTED TO STILL BE BELOW FREEZING IN MOST
AREAS...AS CENTER OF SURFACE HIGH MOVES OVER THE MISSISSIPPI
VALLEY. NEXT POINT OF CONCERN IS WITH A SHORTWAVE THAT WILL BE
MOVING OUT OF THE ROCKIES SUNDAY NIGHT. NARROW UPPER RIDGING WILL
OCCUR ACROSS THE PLAINS ON SUNDAY. THE ECMWF IS A BIT SLOWER THAN
THE GFS/CANADIAN MODELS IN BREAKING THIS RIDGE DOWN...MAINLY DUE
TO A DEEP TROUGH/CUTOFF LOW EXTENDING SOUTH FROM NOVA SCOTIA OVER
THE WESTERN ATLANTIC ON MONDAY. HAVE NOT MADE MUCH CHANGE IN THE
PRECIPITATION CHANCES FOR NOW...MAINLY IN THE SLIGHT CHANCE
RANGE...BUT MOST LIKELY PRECIPITATION OCCURRENCE LOOKS TO BE
MONDAY NIGHT IF IT DID OCCUR.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1129 AM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NONE.
KJB
//DISCUSSION...UPDATED 18Z...
SKIES ARE IN THE PROCESS OF CLEARING ACROSS NORTHEASTERN ILLINOIS
AND NORTHWESTERN INDIANA LATE THIS MORNING. ONCE SKIES DO
CLEAR...THEY SHOULD REMAIN SO FOR THE REMAINED OF THE PERIOD.
SURFACE HIGH PRESSURE WILL DOMINATE ACROSS THE MID MISSISSIPPI
VALLEY THROUGH MUCH OF THURSDAY. THIS WILL CONTINUE TO SET UP WEST
TO SOUTHWESTERLY SURFACE FLOW ACROSS THE AREA. NO WEATHER CONCERNS
ARE EXPECTED IN THE NEXT 36 HOURS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE ON ALL FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY/SATURDAY...CHC LAKE EFFECT SNOW WITH MVFR/IFR POSSIBLE.
SUNDAY/MONDAY...VFR.
TUESDAY...SLT CHC RAIN/SNOW.
BMD
&&
.MARINE...
315 AM CST
FOLLOWING THE PASSAGE OF A COLD FRONT AND WITH HIGH PRESSURE
BUILDING ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
VALLEY...WINDS WILL GRADUALLY DIMINISH. AS THE HIGH PRESSURE SAGS
TO THE SOUTHEAST WEDNESDAY AND THURSDAY...WINDS WILL BECOME
WESTERLY TO 25KT AND EVENTUALLY SOUTHWESTERLY...AS ANOTHER ARCTIC
COLD FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE LAKE
THURSDAY NIGHT. A STRONG PUSH OF COLD AIR MAY BRING WINDS UP TO
GALE FORCE OVER THE FAR NORTHERN PORTIONS OF THE LAKE LATE
THURSDAY INTO THURSDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
956 AM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NONE.
KJB
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE BUILDING ACROSS THE AREA WILL PROVIDE RELATIVELY QUIET
WEATHER AND WILL EVENTUALLY CLEAR OUT CLOUD COVER. THIS MORNING...
LOW LEVEL MOISTURE HAS VERY SLOWLY BEEN ERODING FROM THE NORTHWEST
NEARLY STALLING AT RFD. RUC GUIDANCE SUGGESTS THAT LOW CLOUDS MAY
LINGER INTO THE LATE MORNING OR EARLY AFTERNOON ACROSS THE CHICAGO
AREA...THUS OPTED TO SLOW CLEARING ACROSS ORD/MDW FOR SEVERAL
HOURS. STILL...THE CLOUD DECK HAS BEEN GRADUALLY IMPROVING THROUGH
THE NIGHT AND DO NOT EXPECT MVFR CONDITIONS TO RETURN. NORTHERLY
WINDS THIS MORNING WILL BACK TO THE WEST THROUGH THE DAY AS HIGH
PRESSURE SLIDES SOUTH OF THE FORECAST AREA. FEW LINGERING LAKE
EFFECT SNOW SHOWERS THIS MORNING ACROSS NORTHWEST INDIANA WILL
CONTINUE TO WEAKEN AND SHIFT FARTHER EAST AWAY FROM THE CHICAGO/NW
INDIANA TERMINALS AS WINDS BACK. BMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE ON ALL FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY/SATURDAY...CHC LAKE EFFECT SNOW WITH MVFR/IFR POSSIBLE.
SUNDAY/MONDAY...VFR.
TUESDAY...SLT CHC RAIN/SNOW.
BMD
&&
.MARINE...
315 AM CST
FOLLOWING THE PASSAGE OF A COLD FRONT AND WITH HIGH PRESSURE
BUILDING ACROSS THE NORTHERN PLAINS AND UPPER MISSISIPPI
VALLEY...WINDS WILL GRADUALLY DIMINISH. AS THE HIGH PRESSURE SAGS
TO THE SOUTHEAST WEDNESDAY AND THURSDAY...WINDS WILL BECOME
WESTERLY TO 25KT AND EVENTUALLY SOUTHWESTERLY...AS ANOTHER ARCTIC
COLD FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE LAKE
THURSDAY NIGHT. A STRONG PUSH OF COLD AIR MAY BRING WINDS UP TO
GALE FORCE OVER THE FAR NORTHERN PORTIONS OF THE LAKE LATE
THURSDAY INTO THURSDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
914 AM CST WED FEB 8 2012
.DISCUSSION...
ISSUED 915 AM CST WED FEB 8 2012
WILL BE UPDATING THE FORECAST SHORTLY TO ADJUST THE MORNING PERIOD
WITH LIGHT SNOW AND FLURRIES OVER EASTERN IL WITH LITTLE OR NO
ADDITIONAL ACCUMULATIONS EXPECTED. ALSO ADJUSTING THE SKY COVER
TODAY WITH SLOWING CLEARING DOWN A BIT FROM THE NORTH. HIGHS 32 TO
38F LOOK ON TRACK WITH MILDEST READINGS IN SE IL.
FAIRLY STRONG UPPER LEVEL TROF OVER THE MIDWEST INCLUDING IL HAD A
LARGE AREA OF LOW CLOUDS OVER MUCH OF MO/IL/IN AND SE IA. THERE
WAS A CLEAR SLOT OVER NW IL AS FAR SOUTH AS PEORIA. AREA OF VERY
LIGHT SNOW AND FLURRIES WAS FROM BLOOMINGTON/NORMAL NE AND
DRIFTING SE TOWARD CHAMPAIGN/URBANA. TEMPS RANGED FROM THE UPPER
20S OVER CENTRAL IL NW OF I-70...TO THE MID 30S IN SE IL FROM
ROBINSON TO FLORA SE. NW WINDS 7 TO 13 MPH WAS USHERING IN DRIER
AIR WITH DEWPOINTS RANGING FROM THE UPPER TEENS AND LOWER 20S NW
OF I-55 TO THE UPPER 20S TO NEAR 30F FROM DANVILLE TO TAYLORVILLE
SE.
HI-RESOLUTION 12Z HRRR MODEL ACTUALLY SHOWS POCKETS OF VERY LIGHT
SNOW SHOWERS AND FLURRIES LINGERING OVER CENTRAL IL THROUGH THE
DAY. 12Z NAM...SREF AND RUC MODELS SHOW BRUN OF THE LIGHT SNOW
EAST OF IL TODAY WITH LIGHT POCKETS OF QPF OVER EAST CENTRAL IL
THIS MORNING WHICH BETTER SUPPORTS RADAR TENDS AND LEANED IN THIS
DIRECTION. DID SLOW CLEARING OF THE LOW CLOUDS FROM THE NORTH TODAY
WITH LOW CLOUDS LINGERING MUCH OF TODAY OVER SE IL. 1035 MB HIGH
PRESSURE OVER EASTERN NEBRASKA WILL SETTLE INTO THE MID MS VALLEY
BY THU MORNING HELPING CLEAR THE REST OF THE LOW CLOUDS TONIGHT
AND BRINGING SEASONABLY COLD TEMPS TODAY AND TONIGHT. NW WINDS 7
TO 13 MPH TODAY TO BECOME LIGHT WEST DURING TONIGHT AS HIGH
PRESSURE SETTLES IN.
HUETTL
&&
.AVIATION...
ISSUED 530 AM CST WED FEB 8 2012
THE WEATHER SYSTEM THAT PRODUCED THE LIGHT PRECIPITATION ACRS THE
AREA LAST NIGHT INTO EARLY THIS MORNING WAS BEGINNING TO SHIFT
OFF TO OUR EAST. ALREADY SEEING SKIES CLEAR UP TO OUR NORTH BUT
SOME PATCHES OF MVFR CIGS WERE NOTED ON THE SFC OBS ACRS PARTS
OF EAST CENTRAL AND NE IOWA. TIMING OF CLEARING ACRS THE FCST
AREA THE MAIN FORECAST CHALLENGE THIS MRNG...WITH VFR CONDITIONS
EXPECTED TO OVERSPREAD THE ENTIRE AREA LATER THIS AFTN OR EARLY
THIS EVENING AS HIGH PRESSURE SETTLES IN FROM THE NORTHWEST.
STILL SEEING VARIABLE CEILING HEIGHTS TO OUR NW DESPITE THE PRECIP
SLOWLY MOVING OUT OF THE AREA. PREVAILING CIGS WERE FROM 3500-4500
FEET BUT OCCASIONALLY LOWER TO 1200 FEET...OR EVEN DROP TO BELOW
1000 FEET WITH VSBYS ARND 3 MILES IN LIGHT SNOW AND FOG. FEEL THE
PRECIP WILL LINGER IN CMI AND DEC THRU MID MORNING WITH NOT MUCH
MORE FALLING AT PIA AND SPI AFTR 13Z.
SFC WINDS WILL BE MAINLY FROM A NORTHWEST DIRECTION AT 10 TO 15
KNOTS TODAY...AND THEN TEND TO BACK MORE INTO A WESTERLY DIRECTION
LATE THIS AFTN AND EVENING WITH SPEEDS DECREASING TO AROUND 5 KTS.
SMITH
&&
.PREV DISCUSSION...
ISSUED 250 AM CST WED FEB 8 2012
THE SHORTWAVE MOVING ACROSS THE CENTRAL U.S. WAS CROSSING ILLINOIS
EARLY THIS MORNING...PER WATER VAPOR IMAGERY. AREA OF LIGHT
SNOW...WHICH HAD PRODUCED A DUSTING...HAD LARGELY TAPERED IN
AREAS NORTH OF I-72. DID HAVE SOME LIGHT FREEZING DRIZZLE MIXED IN
EARLY ON AROUND PEORIA AND GALESBURG.
PRIMARY FORECAST ISSUES FOR THIS PACKAGE INVOLVE THE COLD AIR FOR
THIS WEEKEND...AS WELL AS PRECIPITATION CHANCES BEGINNING ON MONDAY.
SHORT TERM...TODAY THROUGH SATURDAY...
HIGH RESOLUTION MODELS STILL SHOWING LIGHT SNOW LINGERING OVER
THE EASTERN CWA EARLY THIS MORNING. REGIONAL RADAR LOOPS SHOWING
SOME PRECIPITATION STILL PRESENT AS FAR NORTH AS THE I-80
CORRIDOR IN NORTHEAST ILLINOIS...MOVING SOUTHWARD...SO THIS
SCENARIO SEEMS PLAUSIBLE. WILL KEEP 30-50 PERCENT POPS GOING EAST
OF I-57 EARLY THIS MORNING BEFORE TAPERING TO FLURRIES.
OTHERWISE...A QUIET PERIOD IS EXPECTED FROM LATE THIS AFTERNOON
THROUGH THURSDAY...AS HIGH PRESSURE DRIFTS SOUTHEAST INTO THE
TENNESSEE VALLEY.
THE COLD SNAP WHICH HAS BEEN ADVERTISED FOR THE LAST SEVERAL DAYS
IS STILL ON TRACK. 00Z MODELS IN GOOD AGREEMENT IN SWEEPING A COLD
FRONT ACROSS THE FORECAST AREA ON FRIDAY. THE FAR SOUTHEAST MAY
STAY IN THE WARMER AIR LONG ENOUGH TO REACH WELL INTO THE 40S...
BUT TEMPERATURES ELSEWHERE IN THE AFTERNOON WILL BE STEADY OR
FALLING. HAVE LOWERED TEMPERATURES FRIDAY NIGHT AND SATURDAY BY A
FEW MORE DEGREES FROM THE EARLIER VALUES. SOME OF THE GUIDANCE
SUGGESTS EVEN COLDER READINGS...BUT LACK OF SNOW COVER MAY HINDER
THAT THOUGHT. THE FRONT ITSELF IS LARGELY EXPECTED TO COME THROUGH
DRY IN OUR AREA...AND WILL ONLY GO WITH 20 POPS ACROSS THE EAST ON
FRIDAY MORNING.
LONG TERM...SUNDAY THROUGH TUESDAY...
TEMPERATURES ON SUNDAY EXPECTED TO STILL BE BELOW FREEZING IN MOST
AREAS...AS CENTER OF SURFACE HIGH MOVES OVER THE MISSISSIPPI
VALLEY. NEXT POINT OF CONCERN IS WITH A SHORTWAVE THAT WILL BE
MOVING OUT OF THE ROCKIES SUNDAY NIGHT. NARROW UPPER RIDGING WILL
OCCUR ACROSS THE PLAINS ON SUNDAY. THE ECMWF IS A BIT SLOWER THAN
THE GFS/CANADIAN MODELS IN BREAKING THIS RIDGE DOWN...MAINLY DUE
TO A DEEP TROUGH/CUTOFF LOW EXTENDING SOUTH FROM NOVA SCOTIA OVER
THE WESTERN ATLANTIC ON MONDAY. HAVE NOT MADE MUCH CHANGE IN THE
PRECIPITATION CHANCES FOR NOW...MAINLY IN THE SLIGHT CHANCE
RANGE...BUT MOST LIKELY PRECIPITATION OCCURRENCE LOOKS TO BE
MONDAY NIGHT IF IT DID OCCUR.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
801 AM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NONE.
KJB
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE BUILDING ACROSS THE AREA WILL PROVIDE RELATIVELY QUIET
WEATHER AND WILL EVENTUALLY CLEAR OUT CLOUD COVER. THIS MORNING...
LOW LEVEL MOISTURE HAS VERY SLOWLY BEEN ERODING FROM THE NORTHWEST
NEARLY STALLING AT RFD. RUC GUIDANCE SUGGESTS THAT LOW CLOUDS MAY
LINGER INTO THE LATE MORNING OR EARLY AFTERNOON ACROSS THE CHICAGO
AREA...THUS OPTED TO SLOW CLEARING ACROSS ORD/MDW FOR SEVERAL
HOURS. STILL...THE CLOUD DECK HAS BEEN GRADUALLY IMPROVING THROUGH
THE NIGHT AND DO NOT EXPECT MVFR CONDITIONS TO RETURN. NORTHERLY
WINDS THIS MORNING WILL BACK TO THE WEST THROUGH THE DAY AS HIGH
PRESSURE SLIDES SOUTH OF THE FORECAST AREA. FEW LINGERING LAKE
EFFECT SNOW SHOWERS THIS MORNING ACROSS NORTHWEST INDIANA WILL
CONTINUE TO WEAKEN AND SHIFT FARTHER EAST AWAY FROM THE CHICAGO/NW
INDIANA TERMINALS AS WINDS BACK. BMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE ON ALL FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY/SATURDAY...CHC LAKE EFFECT SNOW WITH MVFR/IFR POSSIBLE.
SUNDAY/MONDAY...VFR.
TUESDAY...SLT CHC RAIN/SNOW.
BMD
&&
.MARINE...
315 AM CST
FOLLOWING THE PASSAGE OF A COLD FRONT AND WITH HIGH PRESSURE
BUILDING ACROSS THE NORTHERN PLAINS AND UPPER MISSISIPPI
VALLEY...WINDS WILL GRADUALLY DIMINISH. AS THE HIGH PRESSURE SAGS
TO THE SOUTHEAST WEDNESDAY AND THURSDAY...WINDS WILL BECOME
WESTERLY TO 25KT AND EVENTUALLY SOUTHWESTERLY...AS ANOTHER ARCTIC
COLD FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE LAKE
THURSDAY NIGHT. A STRONG PUSH OF COLD AIR MAY BRING WINDS UP TO
GALE FORCE OVER THE FAR NORTHERN PORTIONS OF THE LAKE LATE
THURSDAY INTO THURSDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 11 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
526 AM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* TIMING CLEARING OF CIGS. BMD
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE BUILDING ACROSS THE AREA WILL PROVIDE RELATIVELY QUIET
WEATHER AND WILL EVENTUALLY CLEAR OUT CLOUD COVER. THIS MORNING...
LOW LEVEL MOISTURE HAS VERY SLOWLY BEEN ERODING FROM THE NORTHWEST
NEARLY STALLING AT RFD. RUC GUIDANCE SUGGESTS THAT LOW CLOUDS MAY
LINGER INTO THE LATE MORNING OR EARLY AFTERNOON ACROSS THE CHICAGO
AREA...THUS OPTED TO SLOW CLEARING ACROSS ORD/MDW FOR SEVERAL
HOURS. STILL...THE CLOUD DECK HAS BEEN GRADUALLY IMPROVING THROUGH
THE NIGHT AND DO NOT EXPECT MVFR CONDITIONS TO RETURN. NORTHERLY
WINDS THIS MORNING WILL BACK TO THE WEST THROUGH THE DAY AS HIGH
PRESSURE SLIDES SOUTH OF THE FORECAST AREA. FEW LINGERING LAKE
EFFECT SNOW SHOWERS THIS MORNING ACROSS NORTHWEST INDIANA WILL
CONTINUE TO WEAKEN AND SHIFT FARTHER EAST AWAY FROM THE CHICAGO/NW
INDIANA TERMINALS AS WINDS BACK. BMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* LOW TO MEDIUM CONFIDENCE ON TIMING LOW CIGS CLEARING THIS
MORNING.
* HIGH CONFIDENCE ON ALL OTHER FORECAST ELEMENTS. BMD
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY/SATURDAY...CHC LAKE EFFECT SNOW WITH MVFR/IFR POSSIBLE.
SUNDAY/MONDAY...VFR.
TUESDAY...SLT CHC RAIN/SNOW.
BMD
&&
.MARINE...
315 AM CST
FOLLOWING THE PASSAGE OF A COLD FRONT AND WITH HIGH PRESSURE
BUILDING ACROSS THE NORTHERN PLAINS AND UPPER MISSISIPPI
VALLEY...WINDS WILL GRADUALLY DIMINISH. AS THE HIGH PRESSURE SAGS
TO THE SOUTHEAST WEDNESDAY AND THURSDAY...WINDS WILL BECOME
WESTERLY TO 25KT AND EVENTUALLY SOUTHWESTERLY...AS ANOTHER ARCTIC
COLD FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE LAKE
THURSDAY NIGHT. A STRONG PUSH OF COLD AIR MAY BRING WINDS UP TO
GALE FORCE OVER THE FAR NORTHERN PORTIONS OF THE LAKE LATE
THURSDAY INTO THURSDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 11 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
359 AM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 10Z...
* TIMING CLEARING OF 025-045 VFR CIGS.
BMD
//DISCUSSION...UPDATED 06Z...
LAKE EFFECT SNOW HAS FINALLY MOVED ASHORE AND FLURRIES HAVE MOVED
OVER MDW. NOT EXPECTING ANY SNOW ACCUMULATION FROM THESE
FLURRIES...AND CIGS SHOULD REMAIN ABOVE 015. BASED ON RADAR
TRENDS...THINKING FLURRIES WILL BE SOUTH OF MDW BY 06Z. A MORE
IMPRESSIVE LOOKING LAKE EFFECT SNOW SHOWER BAND HAS FORMED OVER
GARY INDIANA. THINKING THE BAND WILL ONLY PERSIST FOR THE NEXT
COUPLE OF HOURS.
WIND GUSTS HAVE DIMINISHED AS THE PRESSURE GRADIENT OVERHEAD HAS
ALSO WEAKENED. WINDS WILL REMAIN NORTHWESTERLY TONIGHT AND THEN
TURN WESTERLY AS THE HIGH PRESSURE MOVES TOWARD OUR AREA. CIGS
WILL AS BE IMPROVING AS THE HIGH APPROACHES. SKIES ARE CLEARING
IN SOUTHERN WISCONSIN...BUT CANNOT CLEARLY IDENTIFY THE CLEARING
LINE ON SATELLITE IMAGERY DUE TO HIGH LEVEL CIRRUS. THINKING RFD
WILL REACH VFR BY 08Z...AND OTHER SITES MAY GO VFR SOONER THAN
FORECAST. GYY WILL STAY MVFR THE LONGEST AS LAKE EFFECT CLOUDS
WILL PERSIST THROUGH THE EARLY MORNING HOURS. SKIES WILL CLEAR OUT
COMPLETELY LATE WEDNESDAY.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 10Z...
* LOW TO MEDIUM CONFIDENCE ON TIMING 025-045 CIGS CLEARING THIS
MORNING...MOISTURE MAY LINGER UNTIL AFTER DAYBREAK.
* HIGH CONFIDENCE ON ALL OTHER FORECAST ELEMENTS. BMD
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...MVFR/IFR POSSIBLE.
SATURDAY THROUGH MONDAY...VFR.
JEE
&&
.MARINE...
315 AM CST
FOLLOWING THE PASSAGE OF A COLD FRONT AND WITH HIGH PRESSURE
BUILDING ACROSS THE NORTHERN PLAINS AND UPPER MISSISIPPI
VALLEY...WINDS WILL GRADUALLY DIMINISH. AS THE HIGH PRESSURE SAGS
TO THE SOUTHEAST WEDNESDAY AND THURSDAY...WINDS WILL BECOME
WESTERLY TO 25KT AND EVENTUALLY SOUTHWESTERLY...AS ANOTHER ARCTIC
COLD FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE LAKE
THURSDAY NIGHT. A STRONG PUSH OF COLD AIR MAY BRING WINDS UP TO
GALE FORCE OVER THE FAR NORTHERN PORTIONS OF THE LAKE LATE
THURSDAY INTO THURSDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 11 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
357 AM CST WED FEB 8 2012
.DISCUSSION...
356 AM CST
NEAR TERM CONCERNS THIS MORNING INCLUDE LIGHT SNOW ACROSS SOUTHERN
PARTS OF THE CWA...LINGERING LIGHT LAKE EFFECT SNOW THIS MORNING
OVER NORTHERN LAKE AND PORTER COUNTIES...AND CLOUD TRENDS ACROSS THE
AREA TODAY. LOOMING ON THE HORIZON IS A PUNCH OF ARCTIC AIR WHICH
ARRIVES FRIDAY...WITH THE FOCUS ON COLDER TEMPS AND THE POTENTIAL
FOR MORE SIGNIFICANT LAKE EFFECT SNOW ACROSS NORTHEAST IL AND
NORTHWEST INDIANA INTO SATURDAY.
LIGHT SNOW WAS OCCURRING EARLY THIS MORNING GENERALLY SOUTH OF A VYS
TO VPZ LINE...IN ASSOCIATION WITH AN UPPER DISTURBANCE MOVING ACROSS
DOWNSTATE IL INTO THE LOWER OHIO VALLEY. STRONGEST FORCING WITH THIS
SYSTEM WAS OCCURRING SOUTH OF THE CWA...WITH SFC OBS ACROSS OUR
SOUTHERN COUNTIES INDICATING VISIBILITIES GENERALLY IN THE 3-7SM
RANGE AND SUGGESTING ONLY MINOR ACCUMULATIONS. LIGHT SNOW WILL
CONTINUE ACROSS THE SOUTH THIS MORNING...SHIFTING MAINLY EAST OF
INTERSTATE 57 BY 12Z. LITTLE ADDITIONAL ACCUMULATION IS EXPECTED.
FARTHER NORTH...A WEAK BAND OF LAKE EFFECT SNOW WAS IMPINGING ON
NORTHWEST LAKE COUNTY AND FAR SOUTHEAST COOK COUNTY. BAND WAS
HEAVIER FOR A TIME LATE LAST EVENING...WITH SOME ACCUMULATION NOTED
ON WEB CAMS ALONG THE INTERSTATES. RADAR RETURNS HAVE WEAKENED
CONSIDERABLY...AND HIGH RES MODEL GUIDANCE SEEMS TO HAVE CAPTURED
THIS TREND NICELY. BOTH RUC AND NAM DO INDICATE THAT SLIGHT COOLING
AROUND 900 HPA MAY SLIGHTLY IMPROVE THE LOW-LEVEL THERMODYNAMIC
PROFILE AROUND 12Z THIS MORNING...BEFORE EQUILIBRIUM HEIGHTS LOWER
BELOW 4000 FT AND LOW LEVEL WINDS BACK AROUND TO THE NORTHWEST BY
MIDDAY. THEREFORE EXPECT LIGHT SNOW SHOWERS TO CONTINUE THROUGH MID
MORNING...SHIFTING EAST AND WEAKENING WITH TIME IN THE 15-18Z
PERIOD. CURRENT WEB CAM VIEWS FROM 80/94 NEAR HAMMOND INDICATE
CURRENT ACTIVITY HAVING LITTLE/NO IMPACT ON VISIBILITY AT 330
AM...AND HAVE ONLY INCLUDED AN ADDITIONAL TENTH OF AN INCH OF
SNOWFALL THIS MORNING MAINLY ACROSS NORTHERN LAKE COUNTY...THOUGH
WILL MONITOR FOR ANY SIGNS OF BETTER DEVELOPMENT PRIOR TO SUNRISE.
GOES 11-3.9 MICRON IMAGERY SHOWS CLEARING OF LOW CLOUDS WAS
OCCURRING ACROSS FAR NORTHWEST IL EARLY THIS MORNING...THOUGH LOW
CLOUDS STRETCHED BACK ACROSS A LARGE PORTION OF CENTRAL IA. A SHORT
WAVE TROUGH DIGGING SOUTHEAST ACROSS THE HAWKEYE STATE MAY SLOW
CLEARING FOR A TIME THIS MORNING...BEFORE THE MID-LEVEL VORT AND
TROUGH AXIS PASS INTO CENTRAL IL EARLY THIS AFTERNOON. DRIER LOW
LEVEL AIR JUST UPSTREAM WILL ADVECT INTO THE AREA FROM THE NORTHWEST
HOWEVER WHICH SHOULD ALLOW CLEARING FROM THE NORTH/NORTHWEST THROUGH
THE DAY...WITH SOUTHEASTERN COUNTIES CLEARING LAST. MODEL
TIME/HEIGHT SECTIONS THEN APPEAR QUITE DRY TONIGHT THROUGH THURSDAY.
TEMPERATURE GUIDANCE IN FAIRLY CLOSE AGREEMENT DURING THIS PERIOD
AND GENERALLY USED A BLEND LEANING A LITTLE TOWARD THE COOLER
NUMBERS TODAY...AND TOWARD THE WARMER END OF THE RANGE WITH MORE SUN
AND WEAK WARM ADVECTION DEVELOPING THURSDAY.
GUIDANCE CONTINUES TO DEPICT SIGNIFICANT AMPLIFICATION OF THE UPPER
FLOW FOR THE END OF THE WEEK...WITH LARGE TROUGH DEVELOPING OVER
MUCH OF EASTERN NORTH AMERICA AND AT LEAST A TEMPORARY PUSH OF
ARCTIC AIR. MAIN AREA OF LOW PRESSURE IS PROGGED TO DEVELOP JUST
NORTH OF LAKE SUPERIOR ON THURSDAY AHEAD OF MID-LEVEL SHORT WAVE...
WITH UPPER WAVE AND SURFACE COLD FRONT PUSHING ACROSS THE FORECAST
AREA EARLY FRIDAY. MODELS INDICATE CONSIDERABLE DRY AIR IN THE
850-650 HPA LAYER PRECLUDING MUCH OF A PRECIPITATION THREAT...THOUGH
FAIRLY STRONG ISENTROPIC ASCENT IN THE WARM ADVECTION AHEAD OF THE
TROUGH MAY RESULT IN ENOUGH SATURATION IN THE 280-285 K LAYER TO
PRODUCE SOME FLURRIES FRIDAY MORNING. STRONG COLD ADVECTION ON
BLUSTERY NORTHERLY WINDS FRIDAY WILL LIKELY PRODUCE FALLING DAYTIME
TEMPS INTO THE 20S...WITH 850 HPA TEMPS FROM GFS/ECMWF DEPICTING -17
TO -19 C OVER THE AREA BY 12Z SATURDAY.
BESIDES THE COLD...THE REAL FORECAST CONCERN IN THE FRIDAY-SATURDAY
PERIOD IS THE POTENTIAL FOR LAKE EFFECT SNOW INTO NORTHEAST IL AND
NORTHWEST INDIANA. LAKE SURFACE TO 850 HPA DELTAS INCREASE INTO THE
LOW 20S LATE FRIDAY THROUGH SATURDAY MORNING...DURING A PERIOD IN
WHICH THE LOW LEVEL WINDS WILL BE NORTH-NORTHEAST DOWN THE FULL
FETCH OF THE LAKE. FORECAST SOUNDINGS INDICATE EQUILIBRIUM LEVELS
RISING TO NEAR 9000 FT BY 12Z SATURDAY...WITH LAKE INDUCED CAPES OF
400-500 J/KG. THIS WOULD SUGGEST THE POTENTIAL FOR SOME SIGNIFICANT
ACCUMULATING LAKE EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY
MORNING. ONLY LIMITING FACTOR WOULD BE THE VERY DRY ARCTIC AIR
SPREADING ACROSS THE WESTERN LAKES...THOUGH THE LONG FETCH WILL
LIKELY PROVIDE ENOUGH MOISTURE FLUX TO MAKE UP FOR THE DRYNESS OF
THE AIRMASS. WILL BE INTERESTING TO SEE SOME OF THE HIGH RESOLUTION
GUIDANCE AS THE FRIDAY-SATURDAY PERIOD APPROACHES. FOR NOW HAVE
INCREASED POPS FOR THE LAKESIDE COUNTIES...AND WILL HIGHLIGHT
POTENTIAL FOR ACCUMULATING LAKE SNOWS IN THE HAZARDOUS WEATHER
OUTLOOK.
LONGER RANGE GUIDANCE IN A LITTLE BETTER AGREEMENT IN SHIFTING UPPER
TROUGH OFF TO THE EAST SUNDAY...AND BUILDING SURFACE HIGH PRESSURE
RIDGE IN FROM THE WEST SUNDAY NIGHT. WARM ADVECTION WORKS TO PUSH
THE ARCTIC AIR AWAY MONDAY AS LOW LEVEL WINDS SHIFT TO THE SOUTH.
BOTH OPERATIONAL ECMWF AND GFS INDICATE A SHORT WAVE LIFTING
NORTHEAST ACROSS THE REGION LATE MONDAY SUGGESTING POTENTIAL FOR
SOME LIGHT SNOW MONDAY NIGHT INTO TUESDAY...WITH TEMPS CLIMBING A
BIT BACK ABOVE NORMAL.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* TIMING CLEARING OF MVF/LOW VFR CIGS.
BMD
//DISCUSSION...UPDATED 06Z...
LAKE EFFECT SNOW HAS FINALLY MOVED ASHORE AND FLURRIES HAVE MOVED
OVER MDW. NOT EXPECTING ANY SNOW ACCUMULATION FROM THESE
FLURRIES...AND CIGS SHOULD REMAIN ABOVE 015. BASED ON RADAR
TRENDS...THINKING FLURRIES WILL BE SOUTH OF MDW BY 06Z. A MORE
IMPRESSIVE LOOKING LAKE EFFECT SNOW SHOWER BAND HAS FORMED OVER
GARY INDIANA. THINKING THE BAND WILL ONLY PERSIST FOR THE NEXT
COUPLE OF HOURS.
WIND GUSTS HAVE DIMINISHED AS THE PRESSURE GRADIENT OVERHEAD HAS
ALSO WEAKENED. WINDS WILL REMAIN NORTHWESTERLY TONIGHT AND THEN
TURN WESTERLY AS THE HIGH PRESSURE MOVES TOWARD OUR AREA. CIGS
WILL AS BE IMPROVING AS THE HIGH APPROACHES. SKIES ARE CLEARING
IN SOUTHERN WISCONSIN...BUT CANNOT CLEARLY IDENTIFY THE CLEARING
LINE ON SATELLITE IMAGERY DUE TO HIGH LEVEL CIRRUS. THINKING RFD
WILL REACH VFR BY 08Z...AND OTHER SITES MAY GO VFR SOONER THAN
FORECAST. GYY WILL STAY MVFR THE LONGEST AS LAKE EFFECT CLOUDS
WILL PERSIST THROUGH THE EARLY MORNING HOURS. SKIES WILL CLEAR OUT
COMPLETELY LATE WEDNESDAY.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* MEDIUM CONFIDENCE ON TIMING 025-040 CIGS CLEARING THIS MORNING.
* HIGH CONFIDENCE ON ALL OTHER FORECAST ELEMENTS.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...MVFR/IFR POSSIBLE.
SATURDAY THROUGH MONDAY...VFR.
JEE
&&
.MARINE...
315 AM CST
FOLLOWING THE PASSAGE OF A COLD FRONT AND WITH HIGH PRESSURE
BUILDING ACROSS THE NORTHERN PLAINS AND UPPER MISSISIPPI
VALLEY...WINDS WILL GRADUALLY DIMINISH. AS THE HIGH PRESSURE SAGS
TO THE SOUTHEAST WEDNESDAY AND THURSDAY...WINDS WILL BECOME
WESTERLY TO 25KT AND EVENTUALLY SOUTHWESTERLY...AS ANOTHER ARCTIC
COLD FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE LAKE
THURSDAY NIGHT. A STRONG PUSH OF COLD AIR MAY BRING WINDS UP TO
GALE FORCE OVER THE FAR NORTHERN PORTIONS OF THE LAKE LATE
THURSDAY INTO THURSDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 11 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1015 AM EST WED FEB 8 2012
.UPDATE...
THE SYNOPSIS AND NEAR TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
A FEW DISTURBANCES WILL BRING SNOW TO CENTRAL INDIANA OVER THE
NEXT FEW DAYS. BRIEF RIDGING WILL BUILD INTO THE AREA THROUGH
TOMORROW BEFORE ANOTHER DISTURBANCE BRINGS THE NEXT ROUND OF SNOW
ON FRIDAY AND FRIDAY NIGHT. ACCUMULATIONS WILL BE MINIMAL THOUGH.
FURTHER OUT...A QUICK DISTURBANCE WILL PASS OVER CENTRAL INDIANA
AT THE BEGINNING OF NEXT WEEK...BUT THIS LOOKS TO BE MORE OF A
RAIN/SNOW EVENT.
&&
.NEAR TERM /REST OF TODAY/...
ACCUMULATING SNOW HAS PRETTY MUCH ENDED ACROSS CENTRAL
INDIANA...BUT FLURRIES LINGER ACROSS THE AREA. HAVE UPDATED POPS
AND WEATHER TO REFLECT THIS. FLURRIES SHOULD STILL END BY EARLY
AFTERNOON AS FORCING EXITS.
SATELLITE SHOWS SOME BREAKS IN THE CLOUDS ACROSS NORTHEAST INDIANA
AS WELL AS NORTHWEST ILLINOIS. HOWEVER THE BREAKS ACROSS ILLINOIS
ARE NOT GROWING...AND GENERAL TREND OF CLOUDS ACROSS NORTHERN
INDIANA IS FOR THEM TO FILL IN FROM WEST TO EAST. WITH A BIT OF
UPPER ENERGY STILL TO THE NORTHWEST...RECENT SATELLITE TRENDS...AND
TENDENCY OF LOW CLOUDS TO HANG TOUGH...HAVE WENT MORE PESSIMISTIC
WITH CLOUD COVER TODAY.
GIVEN THE ABOVE DO NOT EXPECT BIG RISES IN TEMPERATURES TODAY...SO
ONLY MADE MINOR TWEAKS TO HIGHS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS SNOW CHANCES ON FRIDAY/FRIDAY
NIGHT WITH A BROAD UPPER LEVEL LOW.
SKIES WILL BECOME CLEAR TONIGHT AS FLOW BECOMES MORE ZONAL. THIS
SHOULD ALLOW TEMPS TO FALL INTO THE LOWER 20S. AGAIN...WENT WITH A
MODEL BLEND. CLEAR SKIES AND DRY CONDITIONS WILL CONTINUE THROUGH
FRIDAY MORNING. HOWEVER...A BROAD UPPER LEVEL TROUGH WILL AFFECT
THE GREAT LAKES REGION ON FRIDAY...SPREADING SNOW INTO CENTRAL
INDIANA. THIS EVENT WILL BE QUICK JUST LIKE TODAY/S WITH THE BEST
LIFT MOVING THROUGH IN THE SATURDAY 00-06Z TIME FRAME.
HOWEVER...MOISTURE APPEARS LIMITED AT THIS TIME. SO...AMOUNTS
SHOULDN/T BE MUCH MORE THAN A HALF AN INCH WITH THE INITIAL BAND.
ADDITIONAL LAKE EFFECT SNOW SHOWERS ON SATURDAY COULD ADD AN
ADDITIONAL QUARTER TO HALF INCH TO THE TOTALS.
TEMPS WILL BE MILD ON THURSDAY WITH HIGHS STILL IN THE UPPER
30S/LOW 40S...AND LOWS IN THE 20S ON THURSDAY AND FRIDAY NIGHTS
DUE TO INCREASED CLOUD COVER. BUT...THEY WILL DECREASE SUBSTANTIALLY
BEHIND THIS DISTURBANCE AS DEEPER COLD AIR IS ABLE TO FILTER INTO
CENTRAL INDIANA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
COLDER PATTERN SETTING UP FOR THE WEEKEND AS SHARP UPPER TROUGH
DEVELOPS OVER THE EASTERN PART OF THE COUNTRY WITH DEEP POLAR VORTEX
PRESENT OVER QUEBEC. LINGERING SNOW SHOWERS AND FLURRIES LIKELY TO
STILL BE GOING OVER PORTIONS OF THE FORECAST AREA SATURDAY MORNING
AS THE TROUGH AXIS SHIFTS EAST. PRESENCE OF FAVORABLE N/NW LOW LEVEL
WIND FIELDS MAY PROVIDE FOR SOME LAKE ENHANCEMENT TO SNOW SHOWERS
INTO NORTHEAST PORTIONS OF THE FORECAST AREA SATURDAY MORNING.
EVENTUALLY DRIER AIR WILL BUILD IN SATURDAY AFTERNOON AND EVENING AS
WINDS BACK AND BROAD ARCTIC HIGH PRESSURE EXPANDS INTO THE OHIO
VALLEY. EXPECT TEMPS TO REMAIN IN THE 20S ON SATURDAY AS 850MB TEMPS
BOTTOM OUT AROUND -16C. LOWS IN THE TEENS ARE LIKELY SATURDAY NIGHT.
HIGH PRESSURE WILL MAINTAIN DRY WEATHER FOR CENTRAL INDIANA FOR
SUNDAY INTO EARLY NEXT WEEK WITH A SLOW RECOVERY IN TEMPERATURES AS
WARM ADVECTION COMMENCES IN THE LOWER LEVELS. HIGHS SHOULD WARM BACK
INTO THE MID AND UPPER 30S BY MONDAY. UNSETTLED WEATHER RETURNING
FOR THE END OF THE EXTENDED AS UPPER LEVEL RIDGE BUCKLES TO EAST AND
IS REPLACED BY AN UPPER LEVEL DISTURBANCE MONDAY NIGHT. ECMWF...OP
GFS AND GGEM IN RELATIVELY GOOD AGREEMENT WITH JUST SUBTLE TIMING
DIFFERENCES REGARDING TRACK OF THIS SYSTEM. WILL CARRY LOW CHANCE
POPS AS LIGHT PRECIPITATION IMPACTS THE FORECAST AREA MONDAY NIGHT
AND TUESDAY. PRECIP TYPE IS MURKIER AS SURFACE TEMPS MAY SNEAK BELOW
FREEZING WITH WARMER AIR ALOFT. CARRYING A RA/SN MIX MONDAY NIGHT
WITH A SHIFT TO MAINLY RAIN TUESDAY AS LOWER LEVEL THICKNESSES WARM
ENOUGH TO SUPPORT. MORE SUBSTANTIAL UPPER LEVEL SYSTEM WILL LIFT
INTO THE OHIO VALLEY ON WEDNESDAY/THURSDAY WITH A CHANCE FOR MORE
WIDESPREAD PRECIPITATION.
&&
.AVIATION /DISCUSSION FOR 081500Z TAF UPDATES/...
KEPT IFR CONDITIONS IN AT BMG THROUGH 17Z AND HUF THROUGH 16Z BASED
ON TRENDS AND THEN MVFR AFTER. MEANWHILE...ALTHOUGH IND AND LAF HAVE
BRIEFLY JUMPED TO VFR...UPSTREAM OBS SUGGEST A RETURN TO MVFR.
PREVIOUS DISCUSSION FOLLOWS...
IFR AND LOWER CONDITIONS THIS MORNING IN LIGHT SNOW...MVFR
CEILINGS THROUGH THIS EVENING.
UPPER LEVEL DISTURBANCE TRAVERSING THE REGION EARLY THIS MORNING
WITH LIGHT SNOW ACROSS CENTRAL INDIANA. VISIBILITIES HAVE BEEN
1-2SM IN HEAVIEST RETURNS WITH CEILINGS AT 400-1000FT AT THE FOUR
TERMINALS. HRRR AND RUC BOTH MOVE THE SNOW EAST OF THE TERMINALS
BY 15Z AND CURRENT RADAR TRENDS SUPPORT THIS TIMING. VISIBILITIES
WILL RECOVER TO MVFR PRIOR TO THE SNOW ENDING.
MODEL SOUNDINGS AND LOW LEVEL RH PROGS INDICATE MVFR STRATOCU WILL
PERSIST FOR THE REMAINDER OF THE DAY WITH LIGHT N/NW FLOW. CLOUDS
NOT LIKELY TO SCATTER UNTIL TRAILING SHORTWAVE PASSES TO THE EAST
THIS EVENING. SURFACE HIGH PRESSURE WITH DEEP SUBSIDENCE WILL
ENABLE CLEARING SKIES LATE. DRIER AIRMASS SHOULD PRECLUDE ANY FOG
FORMATION AT TERMINALS LATE TONIGHT AS WELL. WINDS WILL BACK TO
LIGHT W/NW OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD/50
NEAR TERM...50
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...RYAN/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
959 AM EST WED FEB 8 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A FEW DISTURBANCES WILL BRING SNOW TO CENTRAL INDIANA OVER THE
NEXT FEW DAYS. THE FIRST ONE WILL BE MOVING OUT OF THE AREA BY
LATE MORNING TODAY...BUT EXPECT LIGHT SNOW TO FALL UNTIL THEN
THIS MORNING. BRIEF RIDGING WILL THEN BUILD INTO THE AREA THROUGH
TOMORROW BEFORE ANOTHER DISTURBANCE BRINGS THE NEXT ROUND OF SNOW
ON FRIDAY AND FRIDAY NIGHT. ACCUMULATIONS WILL BE MINIMAL THOUGH
WITH BOTH EVENTS. FURTHER OUT...A QUICK DISTURBANCE WILL PASS OVER
CENTRAL INDIANA AT THE BEGINNING OF NEXT WEEK...BUT THIS LOOKS TO
BE MORE OF A RAIN/SNOW EVENT.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
THE MAIN FOCUS OF THE NEAR TERM IS THE SNOW THIS MORNING.
CURRENT RADAR MOSAIC IS SHOWING WIDESPREAD PRECIP OVER MOST OF
CENTRAL INDIANA...WHICH IS FALLING IN THE FORM OF SNOW. CURRENT
ACTIVITY SHOULD BE THE MAIN SHOW FOR THIS PARTICULAR
DISTURBANCE...TAPERING OFF BY MID MORNING AS UPPER LEVEL LOW MOVES
EAST OF FORECAST AREA. SPS HAS BEEN ISSUED TO HIGHLIGHT IMPACTS
FOR MORNING RUSH HOUR. NO ADJUSTMENTS WERE MADE TO PREVIOUS
FORECAST AMOUNTS. STILL ANTICIPATE AMOUNTS LESS THAN INCH...WITH
LESSER AMOUNTS TO THE NORTH.
AS MENTIONED ABOVE...THIS WILL BE A QUICK EVENT WITH SNOW OUT OF
AREA BY LATE MORNING. NONETHELESS...SKIES WILL REMAIN MOSTLY
CLOUDY ALL DAY...WHICH WILL HINDER TEMPS. HIGHS WILL TOP OFF IN
THE MID TO UPPER 30S...FELT ALL BLEND WAS THE WAY TO GO SINCE THERE
WAS LITTLE DISCREPANCY IN MODELS.
LATEST OBS ARE SHOWING TEMPS IN THE LOW TO MID 30S WITH DEWPOINTS
IN THE UPPER 20S/LOW 30S. WINDS ARE LIGHT AND VARIABLE...AND SNOW
IS FALLING ACROSS MOST OF FORECAST AREA.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS SNOW CHANCES ON FRIDAY/FRIDAY
NIGHT WITH A BROAD UPPER LEVEL LOW.
SKIES WILL BECOME CLEAR TONIGHT AS FLOW BECOMES MORE ZONAL. THIS
SHOULD ALLOW TEMPS TO FALL INTO THE LOWER 20S. AGAIN...WENT WITH A
MODEL BLEND. CLEAR SKIES AND DRY CONDITIONS WILL CONTINUE THROUGH
FRIDAY MORNING. HOWEVER...A BROAD UPPER LEVEL TROUGH WILL AFFECT
THE GREAT LAKES REGION ON FRIDAY...SPREADING SNOW INTO CENTRAL
INDIANA. THIS EVENT WILL BE QUICK JUST LIKE TODAY/S WITH THE BEST
LIFT MOVING THROUGH IN THE SATURDAY 00-06Z TIME FRAME.
HOWEVER...MOISTURE APPEARS LIMITED AT THIS TIME. SO...AMOUNTS
SHOULDN/T BE MUCH MORE THAN A HALF AN INCH WITH THE INITIAL BAND.
ADDITIONAL LAKE EFFECT SNOW SHOWERS ON SATURDAY COULD ADD AN
ADDITIONAL QUARTER TO HALF INCH TO THE TOTALS.
TEMPS WILL BE MILD ON THURSDAY WITH HIGHS STILL IN THE UPPER
30S/LOW 40S...AND LOWS IN THE 20S ON THURSDAY AND FRIDAY NIGHTS
DUE TO INCREASED CLOUD COVER. BUT...THEY WILL DECREASE SUBSTANTIALLY
BEHIND THIS DISTURBANCE AS DEEPER COLD AIR IS ABLE TO FILTER INTO
CENTRAL INDIANA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
COLDER PATTERN SETTING UP FOR THE WEEKEND AS SHARP UPPER TROUGH
DEVELOPS OVER THE EASTERN PART OF THE COUNTRY WITH DEEP POLAR VORTEX
PRESENT OVER QUEBEC. LINGERING SNOW SHOWERS AND FLURRIES LIKELY TO
STILL BE GOING OVER PORTIONS OF THE FORECAST AREA SATURDAY MORNING
AS THE TROUGH AXIS SHIFTS EAST. PRESENCE OF FAVORABLE N/NW LOW LEVEL
WIND FIELDS MAY PROVIDE FOR SOME LAKE ENHANCEMENT TO SNOW SHOWERS
INTO NORTHEAST PORTIONS OF THE FORECAST AREA SATURDAY MORNING.
EVENTUALLY DRIER AIR WILL BUILD IN SATURDAY AFTERNOON AND EVENING AS
WINDS BACK AND BROAD ARCTIC HIGH PRESSURE EXPANDS INTO THE OHIO
VALLEY. EXPECT TEMPS TO REMAIN IN THE 20S ON SATURDAY AS 850MB TEMPS
BOTTOM OUT AROUND -16C. LOWS IN THE TEENS ARE LIKELY SATURDAY NIGHT.
HIGH PRESSURE WILL MAINTAIN DRY WEATHER FOR CENTRAL INDIANA FOR
SUNDAY INTO EARLY NEXT WEEK WITH A SLOW RECOVERY IN TEMPERATURES AS
WARM ADVECTION COMMENCES IN THE LOWER LEVELS. HIGHS SHOULD WARM BACK
INTO THE MID AND UPPER 30S BY MONDAY. UNSETTLED WEATHER RETURNING
FOR THE END OF THE EXTENDED AS UPPER LEVEL RIDGE BUCKLES TO EAST AND
IS REPLACED BY AN UPPER LEVEL DISTURBANCE MONDAY NIGHT. ECMWF...OP
GFS AND GGEM IN RELATIVELY GOOD AGREEMENT WITH JUST SUBTLE TIMING
DIFFERENCES REGARDING TRACK OF THIS SYSTEM. WILL CARRY LOW CHANCE
POPS AS LIGHT PRECIPITATION IMPACTS THE FORECAST AREA MONDAY NIGHT
AND TUESDAY. PRECIP TYPE IS MURKIER AS SURFACE TEMPS MAY SNEAK BELOW
FREEZING WITH WARMER AIR ALOFT. CARRYING A RA/SN MIX MONDAY NIGHT
WITH A SHIFT TO MAINLY RAIN TUESDAY AS LOWER LEVEL THICKNESSES WARM
ENOUGH TO SUPPORT. MORE SUBSTANTIAL UPPER LEVEL SYSTEM WILL LIFT
INTO THE OHIO VALLEY ON WEDNESDAY/THURSDAY WITH A CHANCE FOR MORE
WIDESPREAD PRECIPITATION.
&&
.AVIATION /DISCUSSION FOR 081500Z TAF UPDATES/...
KEPT IFR CONDITIONS IN AT BMG THROUGH 17Z AND HUF THROUGH 16Z BASED
ON TRENDS AND THEN MVFR AFTER. MEANWHILE...ALTHOUGH IND AND LAF HAVE
BRIEFLY JUMPED TO VFR...UPSTREAM OBS SUGGEST A RETURN TO MVFR.
PREVIOUS DISCUSSION FOLLOWS...
IFR AND LOWER CONDITIONS THIS MORNING IN LIGHT SNOW...MVFR
CEILINGS THROUGH THIS EVENING.
UPPER LEVEL DISTURBANCE TRAVERSING THE REGION EARLY THIS MORNING
WITH LIGHT SNOW ACROSS CENTRAL INDIANA. VISIBILITIES HAVE BEEN
1-2SM IN HEAVIEST RETURNS WITH CEILINGS AT 400-1000FT AT THE FOUR
TERMINALS. HRRR AND RUC BOTH MOVE THE SNOW EAST OF THE TERMINALS
BY 15Z AND CURRENT RADAR TRENDS SUPPORT THIS TIMING. VISIBILITIES
WILL RECOVER TO MVFR PRIOR TO THE SNOW ENDING.
MODEL SOUNDINGS AND LOW LEVEL RH PROGS INDICATE MVFR STRATOCU WILL
PERSIST FOR THE REMAINDER OF THE DAY WITH LIGHT N/NW FLOW. CLOUDS
NOT LIKELY TO SCATTER UNTIL TRAILING SHORTWAVE PASSES TO THE EAST
THIS EVENING. SURFACE HIGH PRESSURE WITH DEEP SUBSIDENCE WILL
ENABLE CLEARING SKIES LATE. DRIER AIRMASS SHOULD PRECLUDE ANY FOG
FORMATION AT TERMINALS LATE TONIGHT AS WELL. WINDS WILL BACK TO
LIGHT W/NW OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...RYAN/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
623 AM EST WED FEB 8 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A FEW DISTURBANCES WILL BRING SNOW TO CENTRAL INDIANA OVER THE
NEXT FEW DAYS. THE FIRST ONE WILL BE MOVING OUT OF THE AREA BY
LATE MORNING TODAY...BUT EXPECT LIGHT SNOW TO FALL UNTIL THEN
THIS MORNING. BRIEF RIDGING WILL THEN BUILD INTO THE AREA THROUGH
TOMORROW BEFORE ANOTHER DISTURBANCE BRINGS THE NEXT ROUND OF SNOW
ON FRIDAY AND FRIDAY NIGHT. ACCUMULATIONS WILL BE MINIMAL THOUGH
WITH BOTH EVENTS. FURTHER OUT...A QUICK DISTURBANCE WILL PASS OVER
CENTRAL INDIANA AT THE BEGINNING OF NEXT WEEK...BUT THIS LOOKS TO
BE MORE OF A RAIN/SNOW EVENT.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
THE MAIN FOCUS OF THE NEAR TERM IS THE SNOW THIS MORNING.
CURRENT RADAR MOSAIC IS SHOWING WIDESPREAD PRECIP OVER MOST OF
CENTRAL INDIANA...WHICH IS FALLING IN THE FORM OF SNOW. CURRENT
ACTIVITY SHOULD BE THE MAIN SHOW FOR THIS PARTICULAR
DISTURBANCE...TAPERING OFF BY MID MORNING AS UPPER LEVEL LOW MOVES
EAST OF FORECAST AREA. SPS HAS BEEN ISSUED TO HIGHLIGHT IMPACTS
FOR MORNING RUSH HOUR. NO ADJUSTMENTS WERE MADE TO PREVIOUS
FORECAST AMOUNTS. STILL ANTICIPATE AMOUNTS LESS THAN INCH...WITH
LESSER AMOUNTS TO THE NORTH.
AS MENTIONED ABOVE...THIS WILL BE A QUICK EVENT WITH SNOW OUT OF
AREA BY LATE MORNING. NONETHELESS...SKIES WILL REMAIN MOSTLY
CLOUDY ALL DAY...WHICH WILL HINDER TEMPS. HIGHS WILL TOP OFF IN
THE MID TO UPPER 30S...FELT ALL BLEND WAS THE WAY TO GO SINCE THERE
WAS LITTLE DISCREPANCY IN MODELS.
LATEST OBS ARE SHOWING TEMPS IN THE LOW TO MID 30S WITH DEWPOINTS
IN THE UPPER 20S/LOW 30S. WINDS ARE LIGHT AND VARIABLE...AND SNOW
IS FALLING ACROSS MOST OF FORECAST AREA.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS SNOW CHANCES ON FRIDAY/FRIDAY
NIGHT WITH A BROAD UPPER LEVEL LOW.
SKIES WILL BECOME CLEAR TONIGHT AS FLOW BECOMES MORE ZONAL. THIS
SHOULD ALLOW TEMPS TO FALL INTO THE LOWER 20S. AGAIN...WENT WITH A
MODEL BLEND. CLEAR SKIES AND DRY CONDITIONS WILL CONTINUE THROUGH
FRIDAY MORNING. HOWEVER...A BROAD UPPER LEVEL TROUGH WILL AFFECT
THE GREAT LAKES REGION ON FRIDAY...SPREADING SNOW INTO CENTRAL
INDIANA. THIS EVENT WILL BE QUICK JUST LIKE TODAY/S WITH THE BEST
LIFT MOVING THROUGH IN THE SATURDAY 00-06Z TIME FRAME.
HOWEVER...MOISTURE APPEARS LIMITED AT THIS TIME. SO...AMOUNTS
SHOULDN/T BE MUCH MORE THAN A HALF AN INCH WITH THE INITIAL BAND.
ADDITIONAL LAKE EFFECT SNOW SHOWERS ON SATURDAY COULD ADD AN
ADDITIONAL QUARTER TO HALF INCH TO THE TOTALS.
TEMPS WILL BE MILD ON THURSDAY WITH HIGHS STILL IN THE UPPER
30S/LOW 40S...AND LOWS IN THE 20S ON THURSDAY AND FRIDAY NIGHTS
DUE TO INCREASED CLOUD COVER. BUT...THEY WILL DECREASE SUBSTANTIALLY
BEHIND THIS DISTURBANCE AS DEEPER COLD AIR IS ABLE TO FILTER INTO
CENTRAL INDIANA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
COLDER PATTERN SETTING UP FOR THE WEEKEND AS SHARP UPPER TROUGH
DEVELOPS OVER THE EASTERN PART OF THE COUNTRY WITH DEEP POLAR VORTEX
PRESENT OVER QUEBEC. LINGERING SNOW SHOWERS AND FLURRIES LIKELY TO
STILL BE GOING OVER PORTIONS OF THE FORECAST AREA SATURDAY MORNING
AS THE TROUGH AXIS SHIFTS EAST. PRESENCE OF FAVORABLE N/NW LOW LEVEL
WIND FIELDS MAY PROVIDE FOR SOME LAKE ENHANCEMENT TO SNOW SHOWERS
INTO NORTHEAST PORTIONS OF THE FORECAST AREA SATURDAY MORNING.
EVENTUALLY DRIER AIR WILL BUILD IN SATURDAY AFTERNOON AND EVENING AS
WINDS BACK AND BROAD ARCTIC HIGH PRESSURE EXPANDS INTO THE OHIO
VALLEY. EXPECT TEMPS TO REMAIN IN THE 20S ON SATURDAY AS 850MB TEMPS
BOTTOM OUT AROUND -16C. LOWS IN THE TEENS ARE LIKELY SATURDAY NIGHT.
HIGH PRESSURE WILL MAINTAIN DRY WEATHER FOR CENTRAL INDIANA FOR
SUNDAY INTO EARLY NEXT WEEK WITH A SLOW RECOVERY IN TEMPERATURES AS
WARM ADVECTION COMMENCES IN THE LOWER LEVELS. HIGHS SHOULD WARM BACK
INTO THE MID AND UPPER 30S BY MONDAY. UNSETTLED WEATHER RETURNING
FOR THE END OF THE EXTENDED AS UPPER LEVEL RIDGE BUCKLES TO EAST AND
IS REPLACED BY AN UPPER LEVEL DISTURBANCE MONDAY NIGHT. ECMWF...OP
GFS AND GGEM IN RELATIVELY GOOD AGREEMENT WITH JUST SUBTLE TIMING
DIFFERENCES REGARDING TRACK OF THIS SYSTEM. WILL CARRY LOW CHANCE
POPS AS LIGHT PRECIPITATION IMPACTS THE FORECAST AREA MONDAY NIGHT
AND TUESDAY. PRECIP TYPE IS MURKIER AS SURFACE TEMPS MAY SNEAK BELOW
FREEZING WITH WARMER AIR ALOFT. CARRYING A RA/SN MIX MONDAY NIGHT
WITH A SHIFT TO MAINLY RAIN TUESDAY AS LOWER LEVEL THICKNESSES WARM
ENOUGH TO SUPPORT. MORE SUBSTANTIAL UPPER LEVEL SYSTEM WILL LIFT
INTO THE OHIO VALLEY ON WEDNESDAY/THURSDAY WITH A CHANCE FOR MORE
WIDESPREAD PRECIPITATION.
&&
.AVIATION /DISCUSSION FOR 081200Z TAF ISSUANCE/...
IFR AND LOWER CONDITIONS THIS MORNING IN LIGHT SNOW...MVFR
CEILINGS THROUGH THIS EVENING.
UPPER LEVEL DISTURBANCE TRAVERSING THE REGION EARLY THIS MORNING
WITH LIGHT SNOW ACROSS CENTRAL INDIANA. VISIBILITIES HAVE BEEN
1-2SM IN HEAVIEST RETURNS WITH CEILINGS AT 400-1000FT AT THE FOUR
TERMINALS. HRRR AND RUC BOTH MOVE THE SNOW EAST OF THE TERMINALS
BY 15Z AND CURRENT RADAR TRENDS SUPPORT THIS TIMING. VISIBILITIES
WILL RECOVER TO MVFR PRIOR TO THE SNOW ENDING.
MODEL SOUNDINGS AND LOW LEVEL RH PROGS INDICATE MVFR STRATOCU WILL
PERSIST FOR THE REMAINDER OF THE DAY WITH LIGHT N/NW FLOW. CLOUDS
NOT LIKELY TO SCATTER UNTIL TRAILING SHORTWAVE PASSES TO THE EAST
THIS EVENING. SURFACE HIGH PRESSURE WITH DEEP SUBSIDENCE WILL
ENABLE CLEARING SKIES LATE. DRIER AIRMASS SHOULD PRECLUDE ANY FOG
FORMATION AT TERMINALS LATE TONIGHT AS WELL. WINDS WILL BACK TO
LIGHT W/NW OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
327 AM EST WED FEB 8 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...AN UPPER DISTURBANCE WILL MOVE THROUGH CENTRAL INDIANA
OVERNIGHT AND EARLY WEDNESDAY MORNING BRINGING MEASURABLE SNOW TO
MUCH OF THE AREA FOR THE MORNING COMMUTE. BY WEDNESDAY AFTERNOON
HIGH PRESSURE RIDGING WILL BUILD INTO THE AREA AND BRING DRY WEATHER
UNTIL THE NEXT WAVE ARRIVES ON FRIDAY WITH MORE CHANCES FOR SNOW
THROUGH FRIDAY NIGHT. AFTER THAT THE WEATHER WILL BE QUIET UNTIL THE
NEXT WAVE APPROACHES FOR MONDAY NIGHT.
&&
.NEAR TERM /TONIGHT/...
RADAR MOSAICS CONTINUE TO INDICATE PRECIP CONTINUING TO DEVELOP
ACROSS SE MO AND SOUTHERN ILLINOIS PUSHING NORTHEAST. GIVEN THE
LACK OF ANY PRECIP OVER THE NEXT COUPLE OVER HOURS...HAVE REMOVED
POPS UNTIL AFTER MIDNIGHT. RUC FORECAST SOUNDINGS INDICATE
SATURATION THROUGH THE COLUMN AFTER 09Z. TIME HEIGHT SECTIONS SHOW
SATURATION CONTINUING THROUGH TE MORNING RUSH HOURS...THUS WILL
ISSUE ANOTHER SPS TO HIGHLIGHT THIS. BASED ON RUC AND TEMPS
EXPECTED TO APPROACH WET BULB TEMPS...HAVE TRENDED LOW TEMPS
WARMER.
&&
.SHORT TERM /WEDNESDAY AFTERNOON THROUGH FRIDAY/...
MODELS ARE IN GOOD AGREEMENT SO WILL USE A CONSENSUS APPROACH. THE
UPPER WAVE IS THROUGH THE AREA BY WEDNESDAY AFTERNOON WITH UPPER
RIDGING MOVING INTO THE AREA. THIS WILL KEEP THINGS DRY UNTIL FRIDAY
WHEN ANOTHER WAVE APPROACHES AND BRINGS LOW CHANCES FOR SNOW. FOR
TEMPERATURES GENERALLY WENT NEAR A GUIDANCE AVERAGE...BUT USED
TEMPERATURES COOLER THAN GUIDANCE FOR WEDNESDAY AND FRIDAY HIGHS
WITH COLD ADVECTION AND EXPECTED CLOUD COVER. THIS YIELDED
TEMPERATURES NEAR AVERAGE FOR THIS TIME OF YEAR.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE BEST CHANCES OF PRECIP WILL BE DURING THE FRIDAY NIGHT PERIOD AS
A STRONG UPPER TROUGH ROTATES EAST ACROSS THE GREAT LAKES AND AGAIN
TOWARDS MONDAY NIGHT WARM ADVECTION INCREASES AND A WEAK UPPER LEVEL
DISTURBANCE MOVES THROUGH THE OHIO VALLEY.
WENT PRETTY MUCH TO ALL BLEND POPS FRIDAY NIGHT. BUT IN THE NORTH I
INCREASED THEM A LITTLE AS THERE COULD BE SOME LAKE ENHANCEMENT.
THIS LAKE ENHANCEMENT MAY LINGER INTO SATURDAY SO KEPT SLIGHT
CHANCES ACROSS MUCH OF OUR FAR NORTH. MODELS HAVE TRENDED COLDER
OVER THE WEEKEND AND WENT CLOSER TO THE CONSALL NUMBERS AS THE COLD
UPPER TROUGH MOVES ACROSS THE GREAT LAKES OVER THE WEEKEND.
HIGH PRESSURE WILL MOVE ACROSS OUR REGION SUNDAY AND WARM ADVECTION
STARTS MONDAY. MODELS HAVE TRENDED SLOWER...SO WILL ONLY MENTION
SLIGHT CHANCE OF PRECIP ACROSS OUR FAR SOUTHWEST LATE MONDAY.
MOST MODELS PRODUCE LIGHT PRECIP AMOUNTS AND THICKNESS SHOULD BE LOW
ENOUGH FOR MOSTLY SNOW NORTH AND CENTRAL MONDAY NIGHT. RAISED
TEMPERATURES A LITTLE WITH CLOUDS AND WARM ADVECTION MONDAY NIGHT.
ALL BLEND TEMPERATURES MAY BE A TAD WARM TUESDAY AS THERE WILL BE
LOTS OF CLOUDS. BUT ONLY CHANGE I MADE WAS TO LOWER THE NORTH HALF
A FEW DEGREES IN CASE THERE WAS SOME LEFT OVER SNOWFALL FROM MONDAY
NIGHT.
&&
.AVIATION /DISCUSSION FOR THE 080900Z TAF UPDATE/...
LIGHT SNOW EXPANDING INTO THE NORTHERN HALF OF THE FORECAST AREA
EARLY THIS MORNING. HAVE GONE AHEAD AND SHIFTED KIND TO 4SM WITH -SN
AS FLAKES ARE JUST BEGINNING TO FALL HERE AT WFO INDY. HAVE HELD IFR
CONDITIONS WITHIN A TEMPO GROUP FOR THE TIME BEING AS OB SITES
ACROSS EASTERN ILLINOIS HAVE CONFIRMED. MAY EVENTUALLY NEED TO MAKE
THIS A PREVAILING GROUP WITHIN THE NEXT COUPLE HOURS BUT WILL ADJUST
AS CONDITIONS EVOLVE. MADE ADJUSTMENTS TO KHUF AND KLAF TERMINALS AS
WELL BASED ON CURRENT RADAR ANALYSIS. KHUF HAS MANAGED TO STAY OUT
OF STEADIER SNOW SO FAR BUT THAT IS LIKELY TO CHANGES BY 09-0930Z.
06Z DISCUSSION FOLLOWS.
WEAK UPPER SYSTEM CURRENTLY MOVING INTO WESTERN ILLINOIS RESULTING
IN AREA OF IFR VISIBILITIES/CEILINGS IN LIGHT SNOW. SHORT TERM MODEL
DATA BRING THIS FEATURE ACROSS THE AREA DURING THE EARLY MORNING
HOURS ON WEDNESDAY. EXPECTING A PERIOD OF IFR CONDITIONS IN LIGHT
SNOW AT THE TAF SITES ROUGHLY 080900Z-081400Z. ONCE THIS FEATURE
PASSES...CEILINGS SHOULD SETTLE INTO THE MVFR CATEGORY 015-025
THROUGH 081800Z.
NO WIND ISSUES EXPECTED THROUGH 081800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...PUMA
SHORT TERM...CP
LONG TERM....JH
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1135 PM EST TUE FEB 7 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...AN UPPER DISTURBANCE WILL MOVE THROUGH CENTRAL INDIANA
OVERNIGHT AND EARLY WEDNESDAY MORNING BRINGING MEASURABLE SNOW TO
MUCH OF THE AREA FOR THE MORNING COMMUTE. BY WEDNESDAY AFTERNOON
HIGH PRESSURE RIDGING WILL BUILD INTO THE AREA AND BRING DRY WEATHER
UNTIL THE NEXT WAVE ARRIVES ON FRIDAY WITH MORE CHANCES FOR SNOW
THROUGH FRIDAY NIGHT. AFTER THAT THE WEATHER WILL BE QUIET UNTIL THE
NEXT WAVE APPROACHES FOR MONDAY NIGHT.
&&
.NEAR TERM /TONIGHT/...
RADAR MOSAICS CONTINUE TO INDICATE PRECIP CONTINUING TO DEVELOP
ACROSS SE MO AND SOUTHERN ILLINOIS PUSHING NORTHEAST. GIVEN THE
LACK OF ANY PRECIP OVER THE NEXT COUPLE OVER HOURS...HAVE REMOVED
POPS UNTIL AFTER MIDNIGHT. RUC FORECAST SOUNDINGS INDICATE
SATURATION THROUGH THE COLUMN AFTER 09Z. TIME HEIGHT SECTIONS SHOW
SATURATION CONTINUING THROUGH TE MORNING RUSH HOURS...THUS WILL
ISSUE ANOTHER SPS TO HIGHLIGHT THIS. BASED ON RUC AND TEMPS
EXPECTED TO APPROACH WET BULB TEMPS...HAVE TRENDED LOW TEMPS
WARMER.
&&
.SHORT TERM /WEDNESDAY AFTERNOON THROUGH FRIDAY/...
MODELS ARE IN GOOD AGREEMENT SO WILL USE A CONSENSUS APPROACH. THE
UPPER WAVE IS THROUGH THE AREA BY WEDNESDAY AFTERNOON WITH UPPER
RIDGING MOVING INTO THE AREA. THIS WILL KEEP THINGS DRY UNTIL FRIDAY
WHEN ANOTHER WAVE APPROACHES AND BRINGS LOW CHANCES FOR SNOW. FOR
TEMPERATURES GENERALLY WENT NEAR A GUIDANCE AVERAGE...BUT USED
TEMPERATURES COOLER THAN GUIDANCE FOR WEDNESDAY AND FRIDAY HIGHS
WITH COLD ADVECTION AND EXPECTED CLOUD COVER. THIS YIELDED
TEMPERATURES NEAR AVERAGE FOR THIS TIME OF YEAR.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE BEST CHANCES OF PRECIP WILL BE DURING THE FRIDAY NIGHT PERIOD AS
A STRONG UPPER TROUGH ROTATES EAST ACROSS THE GREAT LAKES AND AGAIN
TOWARDS MONDAY NIGHT WARM ADVECTION INCREASES AND A WEAK UPPER LEVEL
DISTURBANCE MOVES THROUGH THE OHIO VALLEY.
WENT PRETTY MUCH TO ALL BLEND POPS FRIDAY NIGHT. BUT IN THE NORTH I
INCREASED THEM A LITTLE AS THERE COULD BE SOME LAKE ENHANCEMENT.
THIS LAKE ENHANCEMENT MAY LINGER INTO SATURDAY SO KEPT SLIGHT
CHANCES ACROSS MUCH OF OUR FAR NORTH. MODELS HAVE TRENDED COLDER
OVER THE WEEKEND AND WENT CLOSER TO THE CONSALL NUMBERS AS THE COLD
UPPER TROUGH MOVES ACROSS THE GREAT LAKES OVER THE WEEKEND.
HIGH PRESSURE WILL MOVE ACROSS OUR REGION SUNDAY AND WARM ADVECTION
STARTS MONDAY. MODELS HAVE TRENDED SLOWER...SO WILL ONLY MENTION
SLIGHT CHANCE OF PRECIP ACROSS OUR FAR SOUTHWEST LATE MONDAY.
MOST MODELS PRODUCE LIGHT PRECIP AMOUNTS AND THICKNESS SHOULD BE LOW
ENOUGH FOR MOSTLY SNOW NORTH AND CENTRAL MONDAY NIGHT. RAISED
TEMPERATURES A LITTLE WITH CLOUDS AND WARM ADVECTION MONDAY NIGHT.
ALL BLEND TEMPERATURES MAY BE A TAD WARM TUESDAY AS THERE WILL BE
LOTS OF CLOUDS. BUT ONLY CHANGE I MADE WAS TO LOWER THE NORTH HALF
A FEW DEGREES IN CASE THERE WAS SOME LEFT OVER SNOWFALL FROM MONDAY
NIGHT.
&&
.AVIATION /DISCUSSION FOR THE 080600Z TAFS/...
WEAK UPPER SYSTEM CURRENTLY MOVING INTO WESTERN ILLINOIS RESULTING
IN AREA OF IFR VISIBILITIES/CEILINGS IN LIGHT SNOW. SHORT TERM MODEL
DATA BRING THIS FEATURE ACROSS THE AREA DURING THE EARLY MORNING
HOURS ON WEDNESDAY. EXPECTING A PERIOD OF IFR CONDITIONS IN LIGHT
SNOW AT THE TAF SITES ROUGHLY 080900Z-081400Z. ONCE THIS FEATURE
PASSES...CEILINGS SHOULD SETTLE INTO THE MVFR CATEGORY 015-025
THROUGH 081800Z.
NO WIND ISSUES EXPECTED THROUGH 081800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...PUMA
SHORT TERM...CP
LONG TERM....JH
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
600 PM CST THU FEB 9 2012
.AVIATION...
STRATUS WITH VFR TO MVFR CIGS WILL PERSIST TNGT AHEAD OF ARCTIC FRONT
WITH WINDS S/SW AROUND 6-12 KTS WITH AN OCCASIONAL HIGHER GUST
POSSIBLE. ARCTIC FRONT TO SWEEP THROUGH THE TERMINALS BETWEEN
ROUGHLY 10Z-14Z FRI AND WILL BRING GUSTY N/NW WINDS 15-25+ KTS ALONG
WITH MORE WIDESPREAD MVFR CIGS AND POSSIBLY FEW FLURRIES. FEW SHSN
POSSIBLE AFT 15Z... AS ATMOSPHERE BECOMES MORE UNSTABLE. STRONG
SUBSIDENCE SHOULD RESULT IN DECREASING LOW CLOUDS IN THE AFTN LEAVING
ONLY SOME HIGH LEVEL CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 305 PM CST THU FEB 9 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS SEVERAL SHORTWAVE TROFS FROM THE GREAT LAKES
BACK INTO THE PLAINS. AN 850MB COLD FRONT RAN FROM CANADIAN UA SITE
CYEG IN ALBERTA PROVINCE TO THE SOUTH EDGE OF JAMES BAY. SATELLITE
TRENDS THROUGH MID AFTERNOON SHOW THE LOW CLOUDS MOVING EAST ACROSS
THE AREA WITH CLEARING ACROSS SOUTHERN MINNESOTA AND WISCONSIN. THE
LOW POST FRONTAL CLOUDS OF THE ARCTIC FRONT WERE ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA.
18Z SFC ANALYSIS HAD A RIDGE RUNNING FROM THE LOWER MISSISSIPPI
VALLEY INTO THE OHIO VALLEY. THE ARCTIC FRONT RAN FROM EASTERN
MONTANA INTO NORTHWEST MINNESOTA. DEW POINTS ACROSS THE MIDWEST WERE
GENERALLY IN THE TEENS AND 20S WITH 30S IN THE SOUTHERN PLAINS AND
EASTERN KANSAS.
SHORT TERM...TONIGHT AND FRIDAY...
THE SHALLOW NATURE OF THE CLOUDS...ROUGHLY 1-2KFT...IS ONE OF MANY
REASONS WHY THE MODELS ARE DOING AN EXTREMELY POOR JOB OF DEPICTING
THEM AND HANDLING THEIR OVERALL MOVEMENT. THESE CLOUDS PLAY
SIGNIFICANTLY INTO SENSIBLE WX TRENDS TONIGHT BEFORE THE ARCTIC
FRONT ARRIVES.
THE RUC AND WRF HAVE A VAGUE IDEA ABOUT THE CLOUDS AND EITHER THE
0.5-1KM LAYER OR 0.5KM LAYER IS AT LEAST HINTING AT THE CLOUDS.
USING THIS ALONG WITH EXTRAPOLATION FROM CURRENT SATELLITE TRENDS
RESULTS IN CLOUDY SKIES FOR THE REMAINDER OF THE AFTERNOON AND INTO
THE EVENING HOURS. BASED ON THE CURRENT CLEAR AREA TO THE NORTH AND
WHAT THE MODELS ARE SUGGESTING...THE CLOUDS SHOULD PARTIALLY BREAK
UP ACROSS THE NORTHERN THIRD OF THE CWFA LATE THIS EVENING. WHAT
PARTIAL CLEARING THAT DEVELOPS WILL BE FORCED SOUTH AFTER MIDNIGHT
AS THE ARCTIC FRONT STARTS MOVING INTO THE CWFA.
BECAUSE OF THE CLOUDS...TEMPERATURES WILL BE WARMER THAN LAST NIGHT.
ANY AREAS THAT DO SEE PARTIAL OR A TOTAL CLEARING SHOULD DROP AND
THEN REBOUND AS THE POST FRONTAL CLOUDS OF THE ARCTIC FRONT ARRIVE.
THE CAA BEHIND THE ARCTIC FRONT IS IMPRESSIVE. LOW TEMPERATURES
TONIGHT WILL LIKELY OCCUR 7-8 AM FRIDAY MORNING.
ON FRIDAY...THE ARCTIC FRONT WILL CLEAR THE CWFA BY MID TO LATE
MORNING WITH POST FRONTAL STRATUS CLOUDS FOLLOWING BEHIND IT. THE
COMBINATION OF CAA...STRONG CYCLONIC FLOW ALOFT...A STRONG VORT
MAX...STEEPENING LOW LEVEL LAPSE RATES...AND THE STRONGER FEBRUARY
SUN ALL POINT TO SNOW SHOWERS DEVELOPING FROM LATE MORNING THROUGH
THE AFTERNOON. FCST SOUNDINGS DO SHOW SOME SMALL CAPE DEVELOPING AS
LAPSE RATES STEEPEN. PRIOR TO THE SNOW SHOWERS DEVELOPING THERE ARE
REASONABLY LOW CONDENSATION PRESSURE DEFICITS WITH SOME FORCING AND
F VECTOR CONVERGENCE. THUS FLURRIES MAY BE POSSIBLE WITH THE POST
FRONTAL STRATUS BEFORE THE SNOW SHOWERS DEVELOP.
SNOW AMOUNTS WITH THE SNOW SHOWERS WILL BE VARIED. AMOUNTS COULD
RANGE FROM ONLY A TRACE TO AROUND ONE HALF INCH IN THE STRONGER
SHOWERS.
WINDS WILL BE QUITE BRISK ON FRIDAY AND MAY BE LOCALLY STRONGER
AROUND SNOW SHOWERS.
MAX TEMPERATURES FRIDAY WILL LIKELY OCCUR 9-11 AM WITH TEMPERATURES
EITHER STEADY OR SLOWLY FALLING DURING THE AFTERNOON. ..08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
SEASONALLY COLD...A LIGHT SNOW EVENT MONDAY WITH A MODEST WARMING
TREND INTO MIDDLE OF NEXT WEEK.
OVERALL...LARGE SCALE FEATURES REASONABLE BUT LOW LEVEL BL PROBLEMS
CONTINUE WITH MOST SOLUTIONS T/TD PROFILES LOWEST 2K AGL STILL OFF.
MAIN CONTRIBUTOR IS OUR UNSEASONABLY LOW AMOUNTS OF SNOW NOT HANDLED
BY PHYSICS PACKAGES. THIS IS RESULTING IN BL FORECASTS...ESPECIALLY
AMERICAN SOLUTIONS EITHER TOO MOIST OR TOO DRY. INITIALIZATION AND
VERIFICATION AGAIN SUGGESTS A HIGHER WEIGHT BE GIVEN TO COLDEST
GUIDANCE FOR MIN TEMPERATURES WITH ARCTIC AIR IF NOT A FEW DEGREES
COLDER. FOR HIGHS...ON THE WARM END FOR MAX TEMPS INTO MONDAY.
TEXTBOOK WIDESPREAD LIGHT SNOW EVENT MONDAY WITH LOCAL TOOLS
SUGGESTING .5 TO 1.5 INCHES OF SNOW MOST LOCATIONS AT THIS TIME. NEXT
24 HOURS...FINER DETAILS MAY SUGGEST A LEAD VORT MAX...THEN SOME
ISOLATED 2 TO 3 INCHES NOT OUT OF THE QUESTION...THIS SHOULD BE KNOWN
THIS TIME TOMORROW.
FRIDAY NIGHT...CLEARING WITH STRONG CAA WITH NW WINDS 10-20+ MPH IN
THE EVENING DECREASING TO 5-10 MPH OVERNIGHT. LOCAL TECHNIQUES
SUPPORT 0-5F ABOVE NW 1/2 AND 5-10F ABOVE SE 1/2. WHEN ADJUSTING FOR
BL PROBLEMS...POSSIBLE MINS MAY STILL BE 2-5 DEGREES TOO MILD FOR
MANY IF NOT MOST LOCATIONS FOR LATER SIFTS TO REASSESS.
SATURDAY AND SUNDAY...FAIR AND COLD WITH HIGHS UPPER TEENS TO MID 20S
BOTH DAYS AND LOWS SUNDAY AM IN THE SINGLE DIGITS WITH SOME BELOW
ZERO READINGS AGAIN POSSIBLE NW SECTIONS. SUNDAY NIGHT...INCREASING
CLOUDS LATE WITH MINS IN THE TEENS WITH SLOWLY RISING TEMPERATURES
POSSIBLE AFTER MIDNIGHT.
MONDAY... UPPED POPS TO LOW END LIKELY TO HIGH END CHANCE WITH AREAS
OF LIGHT SNOW TO OVERSPREAD AREA THROUGH MONDAY NIGHT. LOCAL TOOLS
SUGGEST MOSTLY .5-1.5 INCHES ATTM WITH RISK OF SOME ISOLATED HIGHER
AMOUNTS OF 2-3 INCHES POSSIBLE IF LEAD VORT MAX IS STRONGER. BL
ISSUES MAKE THIS A CHALLENGE THAT LATER SHIFTS WILL NEED TO STAY ON
TOP OF. HIGHS NEAR FREEZING WITH SOUTH WINDS LIMITING ACCUMULATIONS
ON THE MOST TRAVELED ROADS. MONDAY...LIGHT SNOW TO DIMINISH TO
FLURRIES OR END BY LATE OVERNIGHT HOURS. WITH MINOR ACCUMULATIONS IN
THE FAR EAST UNTIL MIDNIGHT. LOWS WITH CLEARING IN THE NW SECTIONS
MAY NEED TO BE TRIMMED FURTHER BY 2 TO 5 DEGREES.
TUESDAY THROUGH THURSDAY...DRY TO MOSTLY DRY WITH LOW CHANCE POPS ON
WEDNESDAY AND THURSDAY...MOSTLY LOWER SOUTH SECTIONS. MAIN FORCING
IS SUGGESTED TO PASS TO THE SOUTH SO ANY AMOUNTS TO BE LIGHT IF NOT
DRY. LATER SHIFTS MAY BE ABLE TO REMOVE POPS MANY LOCATIONS THE NEXT
FEW DAYS. TEMPERATURES OVERALL TO TREND NEAR TO SLIGHTLY ABOVE
NORMAL. ..NICHOLS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 PM CST WED FEB 8 2012
.SYNOPSIS...
12Z UA ANALYSIS HAS A RIDGE RUNNING FROM THE GULF COAST INTO
EASTERN MONTANA. ARCTIC AIR WAS OVER NORTHERN CANADA WITH THE
SOUTHERN EXTENT DOWN TO JAMES BAY. SATELLITE TRENDS THROUGH MID
AFTERNOON HAD STRATUS TRAPPED UNDER AN INVERSION FROM THE PLAINS
INTO CENTRAL ILLINOIS AND SOUTHEAST IOWA. THE 18Z SFC ANALYSIS HAD
THE RIDGE FROM THE DAKOTAS INTO TEXAS. A WEAK TROF RAN FROM THE
NORTHERN GREAT LAKES INTO WESTERN WISCONSIN. DEW POINTS WERE
GENERALLY IN THE TEENS AND 20S ACROSS MUCH OF THE MIDWEST WITH 30S
IN THE SOUTHERN PLAINS AND OHIO VALLEY.
&&
.SHORT TERM...TONIGHT AND THURSDAY...
THE SHALLOW LAYER OF STRATUS CLOUDS BELOW THE TRAPPING INVERSION IS
NOT BEING HANDLED AT ALL BY THE MODELS. DIURNAL HEATING FROM THE SUN
HAS STRENGTHENED THE INVERSION ABOVE THE CLOUDS CAUSING THE OVERALL
CLEARING TREND TO SLOW.
THE 950MB RH LEVEL ON THE RUC HAS DONE REASONABLY WELL IN DEPICTING
WHERE THE CLOUDS CURRENTLY ARE. USING THE RUC 950MB RH TRENDS
COMBINED WITH EXTRAPOLATION OF SATELLITE INDICATES THAT THE CLOUDS
WILL REMAIN ACROSS ROUGHLY THE SOUTHERN 40 PERCENT OF THE CWFA FOR
THE REMAINDER OF THE AFTERNOON. CLEARING IN THE SOUTH THIRD OF THE
CWFA WILL BE SLOW DURING THE EVENING BUT CLEAR SKIES SHOULD BE SEEN
ACROSS NEARLY ALL THE CWFA BY MIDNIGHT.
AFTER MIDNIGHT ANOTHER UPPER LEVEL DISTURBANCE APPROACHES. THIS
DISTURBANCE SHOULD JUST PASS THROUGH WITH NO NOTICEABLE AFFECTS.
HOWEVER...IF THE LOW CLOUDS ARE STILL IN PLACE ACROSS THE SOUTH
THIRD OF THE CWFA THEN ISOLATED FLURRIES WOULD BE POSSIBLE. FOR NOW
IT APPEARS THAT THE LOW CLOUDS SHOULD EXIT THE CWFA AROUND OR
SHORTLY AFTER MIDNIGHT. ASSUMING CLOUDS CLEAR TONIGHT...TEMPERATURES
SHOULD BE QUITE CHILLY.
THE CLEAR SKIES ON THURSDAY WILL GIVE WAY TO MORE CLOUDS THROUGH THE
DAY. THE 950MB RH FIELD FROM THE WRF...ALTHOUGH NOT AS GOOD THE
RUC...HAS A STRONG SIGNAL INDICATING THE LOW CLOUDS IN NEBRASKA/
KANSAS WILL ADVECT BACK INTO THE CWFA DURING THE MORNING HOURS. CLOUD
COVER FOR THURSDAY HAS BEEN INCREASED BUT IT IS LIKELY TOO LOW. THERE
IS SOME WEAK F VECTOR CONVERGENCE ACROSS THE AREA WHICH COULD PROMOTE
THE DEVELOPMENT OF FLURRIES. HOWEVER...FORCING IS WEAK TO NON-
EXISTENT SO THE CHANCES OF FLURRIES SHOULD BE VERY LOW. THE ARRIVAL
OF CLOUDS ON THURSDAY SHOULD AID IN SUPPRESSING TEMPERATURES.
..08..
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...
THURSDAY NIGHT AND FRIDAY...DIGGING UPPER TROF ACRS CENTRAL CANADA
AND INTO THE WESTERN GRT LKS STILL ON TRACK TO SHUNT AN ARCTIC
FRONT THROUGH THE CWA BY FRI MORNING. VARYING AMOUNTS OF STRATUS
AHEAD OF THIS PROCESS THU EVENING...AND PRE-FRONTAL SOUTHWEST SFC
FLOW MAY HELP TEMPS FROM BOTTOMING OUT THU NIGHT BUT MAY STILL LEAN
TOWARD THE COOLER SIDE OF GUIDANCE AS A BUFFER AGAINST SOME SFC WIND
DECOUPLE IN A DRY SFC LAYER. STEEPENING CYCLONIC FLOW IN A POST-
FRONTAL REGIME AND VORT SPOKE WILL LOOK TO WRING OUT LIGHT SNOW AND
FLURRIES OUT OF ANY POST-FRONTAL STRATUS ON FRI. BREAKS IN CLOUD
COVER AND PROJECTED STEEP LLVL LAPSE RATES MAY MAKE FOR MORE OF A
DIURNAL SNOW SHOWER ACTIVITY AS OPPOSED TO STRATIFORM SNOW ESPECIALLY
ACRS THE NORTHEAST TO EASTERN HALF OF THE DVN CWA. COLD AND BLUSTERY
POST-FRONTAL CONDITIONS WITH HIGHS IN MAINLY IN THE 20S AND
NORTHWEST WINDS OF 15 TO 25 MPH. CLEAR OUT FRI NIGHT AS STRONG 1040+
MB HIGH PRESSURE COMPLEX BUILDS DOWN ACRS THE PLAINS AND UPPER MS RVR
VALLEY INTO SAT MORNING.WITH EXTENT OF INCOMING SFC RIDGE PRESSURE
GRADIENT...EXPECT SOME MIXING NORTH WINDS TO MAINTAIN OVERNIGHT FRI
INTO EARLY SAT MORNING TO PREVENT A BOTTOM OUT IN THE LOW SINGLE
DIGITS OR EVEN BELOW ZERO. MAY STILL GO WITH LOW SINGLE DIGITS IN THE
FAR NORTHWESTERN CWA...TO THE LOWER TEEN IN THE SOUTHEAST.
SATURDAY AND SUNDAY...SREF AND LATEST SUITE OF 12Z RUN MEDIUM RANGE
MODELS IN GOOD AGREEMENT OF SUGGESTING BOUT OF RIDGING TO MAKE FOR A
FAIR BUT CHILLY WEEKEND. BRUNT OF HIGH PRESSURE CENTER PROJECTED TO
SHUTTLE TO THE SOUTH OF THE AREA ACRS THE LOWER MS RVR VALLEY ON SAT
WITH RIDGE LOBE EXTENDING THIS FAR NORTH. MAINLY SUNNY SKIES...LACK
OF SNOW COVER AND CONTINUED MIXING NORTHWEST WINDS OF 10-20 MPH
THROUGH AT LEAST MID AFTERNOON WILL HELP TEMPS GET INTO THE LOW TO
MID 20S...OTHERWISE EXTENT OF COLD AIRMASS IN PLACE WOULD WARRANT
HIGHS IN THE TEENS. SAT NIGHT MAY BE THE COLDEST NIGHT/SECOND NIGHT
AFTER COLD FRONT RULE. CHANCE OF NEAR ZERO OR SUB-ZERO TEMPS IN
NORTHERN PORTIONS OF THE CWA ESPECIALLY IN COLD AIR DRAINAGE
LOCALS. LIGHT RETURN FLOW BEHIND PASSING RIDGE AXIS TO HELP TEMPS
ON SUNDAY REACH THE MID TO UPPER 20S...BUT EXPECT INCREASING HIGH
CLOUDS IN THE AFTERNOON AHEAD OF SOUTHERN STEAM WAVE DEVELOPING
ACRS THE EASTERN GRT BSN. DEPENDING ON EXITING TIMING OF THE ROBUST
HIGH PRESSURE COMPLEX...FIRST BOUT OF OVERRUNNING SNOWS MAY GET CLOSE
TO OR EVEN INTO THE WESTERN CWA LATE SUNDAY NIGHT BUT FOR NOW WILL
BANK ON THE STRENGTH AND SLOWNESS OF THE DENSE RIDGE.
MONDAY THROUGH WEDNESDAY...BOTH THE 12Z RUN GFS AND ECMWF ARE
TRENDING TOWARD ROLLING A LARGE CHUNK OF THE SOUTHERN STREAM WAVE
OUT OVER THE REGION MON INTO TUE MORNING. SOME MOISTURE DRAW IN
INCREASING WARM MOIST CONVEYOR UP OFF THE WESTERN GULF BEHIND
RETREATING RIDGE COMPLEX WILL FUEL ANY ISENTROPIC LIFT OR ELEVATED
FORCES AHEAD OF THIS WAVE. EARLY INDICATIONS BY LATEST 12Z RUN
MODELS ESPECIALLY THE WETTER ECMWF NOW SUGGEST 2-4 INCHES OF SNOW
POSSIBLE ON MONDAY AND INTO MONDAY NIGHT. WILL CONTINUE TO TREND
UP THE POPS BUT SOME TIMING AND MOISTURE INFLUX STILL YET TO EB
REFINED OVER THE NEXT 24-48 HRS. WITH THE CURRENT EXPECTED TIMING...
SNOW SHOULD BE EAST OF THE CWA BY TUE MORNING AND WILL GO DRY WITH
WAKE RIDING. SOUTHWESTERN TROF/SOUTHERN STEAM RELOADS BY MID NEXT
WEEK WITH ANOTHER EVEN LARGER SYSTEM POSSIBLE WED THROUGH THU
DEPENDING ON PHASING OF COURSE. ..12..
&&
.AVIATION...
SATELLITE TRENDS INDICATE THE CLEARING WILL BE SLOWER THAN THOUGHT
IN THE 18Z TAFS. EXTRAPOLATION OF SATELLITE COMBINED WITH RUC TRENDS
SUGGEST VFR CONDITIONS WILL NOT DVLP AT KBRL UNTIL CLOSER TO 06Z/09.
VFR CONDITIONS WILL CONTINUE AT KDBQ AND WILL OCCUR 21Z/08-00Z/09 AT
KCID/KMLI. THERE MAY BE A POTENTIAL FOR SOME MVFR VSBYS PRIOR TO
SUNRISE AT ALL TAF SITES. MVFR CIGS ARE EXPECTED TO MOVE INTO ALL
TAF SITES AFT 14Z/09. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
08/12
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1242 PM CST WED FEB 8 2012
.UPDATE...
DIURNAL HEATING FROM THE STRONGER SUN HAS RESULTED IN A SLOWING OF
THE LOW CLOUD MOVEMENT. EXTRAPOLATION OF CURRENT SATELLITE TRENDS
MAKES CLEARING BEFORE SUNSET IN THE SOUTHERN CWFA QUESTIONABLE.
THE NEWEST RUC TRENDS WOULD ALSO QUESTION THE OVERALL CLEARING IN
THE SOUTH THIS AFTERNOON AS WELL.
THEREFORE...WILL UPDATE THE FCST TO SLOW DOWN THE CLEARING IN THE
SOUTHERN CWFA TO OCCUR AFTER SUNSET. TEMPERATURES HAVE BEEN
ADJUSTED AS WELL TO REFLECT THE SLOWER CLOUD MOVEMENT.
..08..
&&
.PREV DISCUSSION... /ISSUED 1122 AM CST WED FEB 8 2012/
AVIATION...
THE MODELS ARE NOT HANDLING THE SHALLOW CLOUD LAYER TRAPPED BELOW
THE INVERSION. A COMBINATION OF EXTRAPOLATION AND THE RUC WERE
USED TO HANDLE THE MVFR CIGS. KCID/KMLI ARE ON THE EDGE OF THE
MVFR CIGS BUT SHOULD GO VFR PRIOR TO 00Z/09. A THIN SPOT IN THE
CLOUDS HAS ALLOWED KBRL TO GO VFR BUT WILL LIKELY GO BACK TO MVFR
WITH VFR CONDITIONS DVLPG AFT 00Z/09. BASED ON LOW LEVEL FLOW THE
MVFR CIGS IN NEBRASKA/KANSAS WILL ADVECT BACK INTO
KCID/KDBQ/KMLI/KBRL AFT 12Z/09.
.08..
PREV DISCUSSION... /ISSUED 1019 AM CST WED FEB 8 2012/
UPDATE...
CLOUDS ARE TRAPPED UNDER THE INVERSION IN A VERY THIN LAYER.
A MIX OF THE DVN AND ILX 12Z SOUNDINGS IS LIKELY MORE INDICATIVE
OF THE OVERALL ENVIRONMENT. SATELLITE TRENDS THE PAST FEW HOURS
SHOWS A SLOW DRIFT AROUND 10 KTS WITH THE TRAPPED STRATUS TO THE
SOUTHEAST. A SPOTTER HAS REPORTED SOME VERY LIGHT FLURRIES IN
NORTHEAST MISSOURI UNDER THE STRATUS. THIS REPORT MAKES SENSE AS A
SLOW TOP DOWN DRYING OF THE LOWEST LAYERS OCCUR AND WITH THE
PASSAGE OF A VORT MAX/DISTURBANCE IN THAT AREA.
THE FCST IS BEING UPDATED TO BETTER REFLECT CURRENT CLOUD TRENDS
BASED ON EXTRAPOLATION AND SOME INPUT FROM THE RUC. ISOLD FLURRIES
ARE ALSO BEING ADDED IN THE FAR SOUTHERN PARTS OF THE CWFA TO
ACCOUNT FOR THE PASSING VORT MAX. SINCE THE CLOUDS WILL HOLD
AROUND LONGER IN THE SOUTH...TEMPERATURES THERE HAVE BEEN LOWERED
A LITTLE. THERE SHOULD STILL BE A SMALL POP IN TEMPERATURES AS
THE CLOUDS CLEAR LATE THIS AFTERNOON.
AN UPDATED FCST WILL BE OUT BY 1030 AM.
08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1122 AM CST WED FEB 8 2012
.AVIATION...
THE MODELS ARE NOT HANDLING THE SHALLOW CLOUD LAYER TRAPPED BELOW
THE INVERSION. A COMBINATION OF EXTRAPOLATION AND THE RUC WERE
USED TO HANDLE THE MVFR CIGS. KCID/KMLI ARE ON THE EDGE OF THE
MVFR CIGS BUT SHOULD GO VFR PRIOR TO 00Z/09. A THIN SPOT IN THE
CLOUDS HAS ALLOWED KBRL TO GO VFR BUT WILL LIKELY GO BACK TO MVFR
WITH VFR CONDITIONS DVLPG AFT 00Z/09. BASED ON LOW LEVEL FLOW THE
MVFR CIGS IN NEBRASKA/KANSAS WILL ADVECT BACK INTO
KCID/KDBQ/KMLI/KBRL AFT 12Z/09.
..08..
&&
.PREV DISCUSSION... /ISSUED 1019 AM CST WED FEB 8 2012/
UPDATE...
CLOUDS ARE TRAPPED UNDER THE INVERSION IN A VERY THIN LAYER.
A MIX OF THE DVN AND ILX 12Z SOUNDINGS IS LIKELY MORE INDICATIVE
OF THE OVERALL ENVIRONMENT. SATELLITE TRENDS THE PAST FEW HOURS
SHOWS A SLOW DRIFT AROUND 10 KTS WITH THE TRAPPED STRATUS TO THE
SOUTHEAST. A SPOTTER HAS REPORTED SOME VERY LIGHT FLURRIES IN
NORTHEAST MISSOURI UNDER THE STRATUS. THIS REPORT MAKES SENSE AS A
SLOW TOP DOWN DRYING OF THE LOWEST LAYERS OCCUR AND WITH THE
PASSAGE OF A VORT MAX/DISTURBANCE IN THAT AREA.
THE FCST IS BEING UPDATED TO BETTER REFLECT CURRENT CLOUD TRENDS
BASED ON EXTRAPOLATION AND SOME INPUT FROM THE RUC. ISOLD FLURRIES
ARE ALSO BEING ADDED IN THE FAR SOUTHERN PARTS OF THE CWFA TO
ACCOUNT FOR THE PASSING VORT MAX. SINCE THE CLOUDS WILL HOLD
AROUND LONGER IN THE SOUTH...TEMPERATURES THERE HAVE BEEN LOWERED
A LITTLE. THERE SHOULD STILL BE A SMALL POP IN TEMPERATURES AS
THE CLOUDS CLEAR LATE THIS AFTERNOON.
AN UPDATED FCST WILL BE OUT BY 1030 AM.
.08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
411 PM MST THU FEB 9 2012
.DISCUSSION...
225 PM MST THU FEB 9 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS HIGHLY
AMPLIFIED RIDGE ACROSS THE PACIFIC COAST AND A LARGE SCALE TROUGH
ACROSS SOUTHERN CANADA/NORTHERN GREAT LAKES. A SHORTWAVE TROUGH
BETWEEN THESE FEATURES EXTENDS ACROSS THE NORTHERN PLAINS...WITH
ITS MEAN AXIS ALONG THE COLORADO/KANSAS STATE LINE.
TONIGHT...THE UPPER TROUGH CURRENTLY MOVING OVER THE CENTRAL HIGH
PLAINS REGION MOVES EAST OF THE AREA TONIGHT. SUBSIDENCE AND
DRYING ALOFT MOVE OVER IN THE WAKE OF THE TROUGH WITH A GENERAL
DECREASE IN SKY COVER. HIGH PRESSURE OVER THE NORTHERN PLAINS
BEGINS TO MOVE INTO THE REGION WITH WINDS REMAINING OUT OF THE
NORTH-NORTHWEST. WITH A COLDER AREA OF HIGH PRESSURE MOVING
IN...EXPECT TEMPERATURES TONIGHT AND EARLY FRIDAY TO BE NEARLY 10
TO 15 DEGREES COOLER AT MOST LOCATIONS ACROSS THE FORECAST AREA.
LOCKHART
FRIDAY-SUNDAY...COLD AIRMASS SETTLES IN OVER CWA AS A COLD FRONT
MOVES SOUTH OVER CWA AND STRONG SURFACE HIGH BUILDS OVER NORTHERN
PLAINS. A LARGE TEMPERATURE GRADIENT WILL SET UP ACROSS THE SW
PART OF THE CWA. WHILE TEMPS IN THE EXTREME SW CWA MAY REMAIN NEAR
NORMAL DURING THESE PERIODS...THE REST OF THE AREA WILL EXPERIENCE
DAYTIME TEMPS BELOW FREEZING.
DEEP EASTERLY UPSLOPE DEVELOPS BY FRIDAY EVENING WITH ATMOSPHERE
SATURATING BENEATH H7 ACROSS THE CWA. BETTER MID LEVEL MOISTURE/LIFT
WILL SUPPORT SNOW MAINLY OVER THE NORTHERN PART OF THE CWA FRIDAY
NIGHT WHERE AROUND AN INCH OF SNOW IS EXPECTED. BIGGER STORY MAY END
UP BEING THE POTENTIAL FOR FREEZING DRIZZLE AND FREEZING FOG FROM
THE BL TO H7 AROUND -10C FOR MUCH OF THESE PERIODS. THIS COULD
SUPPORT BOTH SUPER COOLED LIQUID AS WELL AS ICE CRYSTALS IN
LOCATIONS IN THE WEST WHERE MID LEVELS ARE MUCH DRIER. THERE
SHOULD ALSO BE BETTER CHANCES FOR DENSE FOG/FREEZING DRIZZLE IN
THE WEST WHERE MOISTURE POOLING ALONG BAROCLINIC ZONE IS MORE
LIKELY. FOR NOW NOT EXPECTING A LOT OF ICE ACCUMULATION...THOUGH A
FEW HUNDREDTHS OF AN INCH COULDNT BE RULED OUT IN THE WEST. IN ANY
CASE A PERIOD OF LIGHT MIXED PRECIP/FOG/LOW STRATUS LOOKS TO BE IN
STORE FRIDAY NIGHT THROUGH EARLY SATURDAY MORNING.
STRATUS/FOG POTENTIAL WILL CONTINUE THROUGH SATURDAY NIGHT/EARLY
SUNDAY MORNING...WITH LITTLE CHANGING IN REGARDS TO UPSLOPE FLOW AND
SURFACE HIGH PRESSURE. AS WEAK SHORTWAVE ENERGY CONTINUES TO PASS
AROUND GREAT LAKES UPPER LOW...I CANT RULE OUT SNOW ACROSS THE
EASTERN CWA THROUGH SUNDAY NIGHT...WHERE I KEPT SLIGHT CHANCE POPS
IN PLACE.
MONDAY-MONDAY NIGHT...SHORTWAVE RIDGE BUILDS IN FROM THE WEST...WHICH
SHOULD HELP BRING NEAR NORMAL TEMPS BACK TO CWA. GUIDANCE STILL
INDICATING LIFT/MOISTURE LINGERING OVER EASTERN PART OF THE CWA...SO
I KEPT SLIGHT CHANCE POPS GOING THROUGH THE DAY. IF OTHER GUIDANCE
TRENDS TOWARDS FASTER NAM SOLUTION THESE POPS COULD PROBABLY BE
REMOVED.
TUESDAY-THURSDAY...NOT A LOT OF CONFIDENCE IN THE FORECAST DURING
THESE PERIODS WITH A LOT OF SPREAD IN REGARDS TO SMALLER SCALE
FEATURES WITHIN A FAIRLY CHAOTIC QUASI-ZONAL PATTERN. ECMWF AND GFS
CONTINUE TO DIFFER ON THE EVOLUTION OF SHORTWAVE TROUGHS ON
WEDNESDAY AND THURSDAY...WHERE BOTH MODELS HAVE BEEN TRYING TO
PRODUCE PRECIP FOR DIFFERENT PARTS OF THE CENTRAL HIGH PLAINS. ECMWF
HAS SHOWN BETTER RUN-RUN CONSISTENTLY THUS FAR...AND WOULD FAVOR A
DRY SOLUTION FOR OUR CWA. GFS CONTINUES TO FAVOR A WETTER
SOLUTION...BUT HAS BEEN LESS CONSISTENT ON THE PLACEMENT OF QPF
BETWEEN MODEL RUNS. FOR NOW I KEPT SLIGHT CHANCE POPS IN PLACE
WEDNESDAY THROUGH THURSDAY TO ACCOUNT FOR THE SPREAD IN SOLUTIONS
AND THE UNCERTAINTY AT THIS RANGE. WAS NOT CONFIDENT ENOUGH TO STRAY
TO FAR FROM NORM ON TEMPS CONSIDERING MODEL SPREAD EACH DAY.
DR
&&
.AVIATION...
411 PM MST THU FEB 9 2012
FOR THE 00Z TAFS...COLD FRONT WILL MOVE ACROSS THE REGION TONIGHT
AND INTO THE DAY ON FRIDAY. RUC/HRRR MODELS INDICATING THE
POSSIBILITY OF MVFR CIGS BEHIND THE FRONT. WINDS WILL SWITCH FROM
THE NORTHWEST TO THE EAST THROUGH THE PERIOD...WHICH WILL SET UP
UPSLOPE CONDITIONS ACROSS THE AREA. LOW LEVEL MOISTURE INCREASES
LATE WHICH WILL LEAD TO MVFR CIGS ESPECIALLY AT KMCK. KGLD WILL
DETERIORATE SHORTLY AFTER THIS TAF CYCLE.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 PM MST THU FEB 9 2012
.DISCUSSION...
225 PM MST THU FEB 9 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS HIGHLY
AMPLIFIED RIDGE ACROSS THE PACIFIC COAST AND A LARGE SCALE TROUGH
ACROSS SOUTHERN CANADA/NORTHERN GREAT LAKES. A SHORTWAVE TROUGH
BETWEEN THESE FEATURES EXTENDS ACROSS THE NORTHERN PLAINS...WITH
ITS MEAN AXIS ALONG THE COLORADO/KANSAS STATE LINE.
TONIGHT...THE UPPER TROUGH CURRENTLY MOVING OVER THE CENTRAL HIGH
PLAINS REGION MOVES EAST OF THE AREA TONIGHT. SUBSIDENCE AND
DRYING ALOFT MOVE OVER IN THE WAKE OF THE TROUGH WITH A GENERAL
DECREASE IN SKY COVER. HIGH PRESSURE OVER THE NORTHERN PLAINS
BEGINS TO MOVE INTO THE REGION WITH WINDS REMAINING OUT OF THE
NORTH-NORTHWEST. WITH A COLDER AREA OF HIGH PRESSURE MOVING
IN...EXPECT TEMPERATURES TONIGHT AND EARLY FRIDAY TO BE NEARLY 10
TO 15 DEGREES COOLER AT MOST LOCATIONS ACROSS THE FORECAST AREA.
LOCKHART
FRIDAY-SUNDAY...COLD AIRMASS SETTLES IN OVER CWA AS A COLD FRONT
MOVES SOUTH OVER CWA AND STRONG SURFACE HIGH BUILDS OVER NORTHERN
PLAINS. A LARGE TEMPERATURE GRADIENT WILL SET UP ACROSS THE SW
PART OF THE CWA. WHILE TEMPS IN THE EXTREME SW CWA MAY REMAIN NEAR
NORMAL DURING THESE PERIODS...THE REST OF THE AREA WILL EXPERIENCE
DAYTIME TEMPS BELOW FREEZING.
DEEP EASTERLY UPSLOPE DEVELOPS BY FRIDAY EVENING WITH ATMOSPHERE
SATURATING BENEATH H7 ACROSS THE CWA. BETTER MID LEVEL MOISTURE/LIFT
WILL SUPPORT SNOW MAINLY OVER THE NORTHERN PART OF THE CWA FRIDAY
NIGHT WHERE AROUND AN INCH OF SNOW IS EXPECTED. BIGGER STORY MAY END
UP BEING THE POTENTIAL FOR FREEZING DRIZZLE AND FREEZING FOG FROM
THE BL TO H7 AROUND -10C FOR MUCH OF THESE PERIODS. THIS COULD
SUPPORT BOTH SUPER COOLED LIQUID AS WELL AS ICE CRYSTALS IN
LOCATIONS IN THE WEST WHERE MID LEVELS ARE MUCH DRIER. THERE
SHOULD ALSO BE BETTER CHANCES FOR DENSE FOG/FREEZING DRIZZLE IN
THE WEST WHERE MOISTURE POOLING ALONG BAROCLINIC ZONE IS MORE
LIKELY. FOR NOW NOT EXPECTING A LOT OF ICE ACCUMULATION...THOUGH A
FEW HUNDREDTHS OF AN INCH COULDNT BE RULED OUT IN THE WEST. IN ANY
CASE A PERIOD OF LIGHT MIXED PRECIP/FOG/LOW STRATUS LOOKS TO BE IN
STORE FRIDAY NIGHT THROUGH EARLY SATURDAY MORNING.
STRATUS/FOG POTENTIAL WILL CONTINUE THROUGH SATURDAY NIGHT/EARLY
SUNDAY MORNING...WITH LITTLE CHANGING IN REGARDS TO UPSLOPE FLOW AND
SURFACE HIGH PRESSURE. AS WEAK SHORTWAVE ENERGY CONTINUES TO PASS
AROUND GREAT LAKES UPPER LOW...I CANT RULE OUT SNOW ACROSS THE
EASTERN CWA THROUGH SUNDAY NIGHT...WHERE I KEPT SLIGHT CHANCE POPS
IN PLACE.
MONDAY-MONDAY NIGHT...SHORTWAVE RIDGE BUILDS IN FROM THE WEST...WHICH
SHOULD HELP BRING NEAR NORMAL TEMPS BACK TO CWA. GUIDANCE STILL
INDICATING LIFT/MOISTURE LINGERING OVER EASTERN PART OF THE CWA...SO
I KEPT SLIGHT CHANCE POPS GOING THROUGH THE DAY. IF OTHER GUIDANCE
TRENDS TOWARDS FASTER NAM SOLUTION THESE POPS COULD PROBABLY BE
REMOVED.
TUESDAY-THURSDAY...NOT A LOT OF CONFIDENCE IN THE FORECAST DURING
THESE PERIODS WITH A LOT OF SPREAD IN REGARDS TO SMALLER SCALE
FEATURES WITHIN A FAIRLY CHAOTIC QUASI-ZONAL PATTERN. ECMWF AND GFS
CONTINUE TO DIFFER ON THE EVOLUTION OF SHORTWAVE TROUGHS ON
WEDNESDAY AND THURSDAY...WHERE BOTH MODELS HAVE BEEN TRYING TO
PRODUCE PRECIP FOR DIFFERENT PARTS OF THE CENTRAL HIGH PLAINS. ECMWF
HAS SHOWN BETTER RUN-RUN CONSISTENTLY THUS FAR...AND WOULD FAVOR A
DRY SOLUTION FOR OUR CWA. GFS CONTINUES TO FAVOR A WETTER
SOLUTION...BUT HAS BEEN LESS CONSISTENT ON THE PLACEMENT OF QPF
BETWEEN MODEL RUNS. FOR NOW I KEPT SLIGHT CHANCE POPS IN PLACE
WEDNESDAY THROUGH THURSDAY TO ACCOUNT FOR THE SPREAD IN SOLUTIONS
AND THE UNCERTAINTY AT THIS RANGE. WAS NOT CONFIDENT ENOUGH TO STRAY
TO FAR FROM NORM ON TEMPS CONSIDERING MODEL SPREAD EACH DAY.
DR
&&
.AVIATION...
1020 AM MST THU FEB 9 2012
FOR THE 18Z TAFS...SKIES WILL REMAIN MOSTLY CLOUDY TODAY AS A
SHORTWAVE TROUGH MOVES OVER THE REGION. WHILE VFR CONDITIONS ARE
EXPECTED OVERNIGHT...THERE IS STILL SOME CONCERN ABOUT REDUCED
VISIBILITIES AT KMCK. A COLD FRONT WILL APPROACH THE REGION ONLY
LATE IN THE PERIOD...SO THE AIR MASS AT KMCK WILL NOT HAVE CHANGED
SINCE LAST NIGHT WHEN THERE WERE REDUCED VISIBILITIES. WINDS AT
KMCK SHOULD BE STRONGER THAN LAST NIGHT THOUGH...AND GIVEN THE
SHALLOW PROFILE OF THE MOISTURE...THESE WINDS ARE EXPECTED TO KEEP
CONDITIONS MIXED ENOUGH TO PREVENT REDUCED VISIBILITIES.
CJS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
255 PM MST WED FEB 8 2012
.DISCUSSION...
235 PM MST WED FEB 8 2012
TONIGHT...SHORTWAVE TROUGH PASSES JUST NORTH OF CWA OVERNIGHT. A
WARM FRONT ON THE BACK SIDE OF THIS FEATURE WILL LIFT NORTHEAST
ACROSS THE CWA 00-06Z...WITH SURFACE HIGH PRESSURE CENTER SHIFTING
EAST TOWARDS NORTHERN MISSOURI. NAM IS SHOWING MODERATE AMOUNT OF
MID LEVEL MOISTURE OVER EASTERN CWA THIS EVENING...POSSIBLY
SUPPORTING A FEW FLURRIES. NOT REALLY CONFIDENT IN THIS. LOW STRATUS
CONTINUES TO LINGER ACROSS MOST OF THE CWA ALONG THE EASTERN EDGE OF
THIS SURFACE HIGH. AS WARM FRONT LIFTS ACROSS AREA NAM/GFS SHOW BL
MOISTURE DECREASING FROM THE WEST TO THE EAST...WITH STRATUS
POSSIBLY LINGERING OVER EASTERN LOCATIONS. LATEST HRRR BEGINNING TO
SHOW FOG DEVELOPMENT AHEAD OF THIS FRONT DURING THE EVENING
HOURS...WITH RUC FAVORING STRATUS. I WASNT CONFIDENT ENOUGH TO ADD
FOG MENTION DURING THIS CYCLE...THOUGH THERE COULD BE A BRIEF
WINDOW.
FRIDAY THROUGH TUESDAY...FORECAST CONCERNS THROUGH THE END OF THE WEEK
AND INTO THE FIRST PART OF NEXT WEEK ARE TEMPERATURES.
NORTHWEST FLOW WILL PERSIST ALOFT ACROSS THE REGION THROUGH
SATURDAY WITH A SHORT WAVE RIDGE MOVING EAST OF THE ROCKIES AND
ACROSS THE CENTRAL PLAINS SATURDAY NIGHT AND SUNDAY. AT THE
SURFACE...A TROUGH MOVES ACROSS THE REGION ON FRIDAY WITH COLDER
AIR BEGINNING TO MOVE INTO THE PLAINS STATES AND BACKING INTO THE
CENTRAL HIGH PLAINS REGION FRIDAY THROUGH FRIDAY NIGHT AND
SATURDAY. AS THIS COLD AIR IS MOVING INTO THE REGION...A WEAK
DISTURBANCE IN THE NORTHWEST FLOW MAY CREATE SOME VERY LIGHT SNOW
IN THE VICINITY OF THE FRONTAL BOUNDARY PUSHING WESTWARD. THERE
MAY BE A POSSIBILITY OF SOME LIGHT FREEZING PRECIPITATION AS IT
INITIATES GIVEN THE MODEL SOUNDINGS WERE HINTING AT WARMER AIR
ALOFT WITH A SHALLOW COLD LAYER AT THE SURFACE...BUT CONFIDENCE AT
THIS POINT IS LOW IN THIS OCCURRING AND HAVE KEPT IT AS ALL LIGHT
SNOW.
A SERIES OF SHORT WAVE TROUGHS MOVES THROUGH THE FLOW LATE IN THE
WEEKEND AND INTO THE BEGINNING OF NEXT WEEK...SO HAVE KEPT AT LEAST
A SLIGHT CHANCE OF VERY LIGHT SNOW IN THE FORECAST THROUGH SUNDAY
NIGHT. HAVE A BRIEF BREAK MONDAY AS A SHORT WAVE RIDGE MOVES
ACROSS THE FORECAST AREA WITH MORE LIGHT SNOW ON TUESDAY WITH THE
NEXT SHORT WAVE TROUGH.
LOCKHART
&&
.AVIATION...
1018 AM MST WED FEB 8 2012
FOR THE 18Z TAFS...LOW STRATUS CONTINUES TO LINGER OVER BOTH KMCK
AND KGLD TERMINALS AT TAF ISSUANCE...WITH MVFR CIGS PREVAILING. CANT
RULE OUT BRIEF PERIODS OF IFR DURING FIRST 6HR OF TAF
PERIOD...HOWEVER OVERALL TREND HAS BEEN TOWARDS CIGS AROUND 1200 FT
AGL. FOR KGLD...LATEST SHORT RANGE GUIDANCE SHOWS CIGS IMPROVING TO
VFR LATER THIS AFTERNOON AS LOW STRATUS SHIFTS EAST. WITH SURFACE
HIGH PRESSURE STILL LINGERING OVER CENTRAL KANSAS/NEBRASKA
TONIGHT...LOW CIGS MAY LINGER THROUGH OVERNIGHT PERIOD AT KMCK. FOR
NOW HAVE GONE WITH TRENDS FROM LATEST 12Z GUIDANCE SHOWING VFR AT
KMCK AROUND 08Z. DAYTIME WINDS AT KGLD WILL REMAIN OUT OF SOUTH
AROUND 10KT TODAY AND OUT OF THE W/NW TOMORROW. OTHERWISE...LIGHT
AND VARIABLE WINDS ARE EXPECTED.
DR
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
315 PM CST WED FEB 8 2012
.DISCUSSION...
MAIN FORECAST CHALLENGES WILL BE TEMPS FOR THE WEEKEND WITH OUR NEXT
POLAR SURGE WITH ATTENTION TURNING TO PRECIP CHANCES AND TYPE FOR
SUN-MON.
SYNOPSIS:
ONE SHORTWAVE IS TRACKING EAST OVER THE OHIO VALLEY WITH ANOTHER PIECE
OF ENERGY DIVING SOUTHEAST OVER WESTERN SD/NW NEBRASKA. MEANWHILE
ANOTHER UPPER IMPULSE EXTENDS OVER THE NORTHERN INTERMOUNTAIN INTO
THE CENTRAL GREAT BASIN. AT THE SURFACE THE HIGH IS CENTERED OVER NW
MO/SW IA WITH SOME RETURN FLOW COMMENCING OVER THE HIGH PLAINS.
TONIGHT-THU:
THE SHORTWAVE ENERGY OVER THE DAKOTAS IS EXPECTED TO MAINTAIN ITS
QUICK SOUTHEAST PROGRESSION AND WILL BE OVER THE MISSOURI VALLEY BY
THU MORNING. AT THE SAME TIME ADDITIONAL UPPER ENERGY WILL MOVE INTO
THE SOUTHERN ROCKIES BY THU MORNING. THIS FEATURE WILL SPREAD PRECIP
CHANCES OVER THE SOUTHERN PLAINS. HOWEVER AT THIS TIME FEEL
CONFIDENT ENOUGH IN THE PRECIP STAYING SOUTH TO KEEP OUT OF THE
FORECAST FOR NOW. A BRIEF WARMUP WILL AFFECT THE AREA THU WITH A RETURN
TO MORE SEASONAL TEMPS.
FRI-SAT:
THE MAIN THEME THROUGH THESE PERIODS WILL BE FOR ARCTIC AIR TO
INVADE THE AREA.
SHORTWAVE ENERGY IS EXPECTED TO DIVE OUT OF ALBERTA/SASKATCHEWAN AND
INTO THE NORTHERN PLAINS THU NIGHT. THIS WILL PULL THE POLAR VORTEX
TO THE SOUTHWEST WHICH WILL ALLOW SOME VERY COLD AIR TO SPILL SOUTH
ON FRI WITH THE FRONT PASSING THROUGH THE FORECAST AREA DURING THE
DAY. CONFIDENCE IS VERY HIGH THAT WELL BELOW NORMAL TEMPS WILL BE IN
PLACE FOR BOTH FRI AND ESPECIALLY SAT WHICH AGREES WELL WITH FORECASTED
STANDARDIZED ANOMALIES.
SUN-WED:
THE FOCUS OF THESE PERIODS WILL BE A FAST MOVING WAVE THAT IS
EXPECTED TO SPREAD SOME PRECIP ACROSS THE AREA FOR THE SUN NIGHT-MON
TIME FRAME. BOTH THE GFS AND ECMWF AGREE ON TRACKING THIS SYSTEM
ACROSS THE DESERT SW ON SUN AND KICKING OUT INTO THE SOUTHERN HIGH
PLAINS ON SUN NIGHT. THIS WILL PLACE THE BEST LIFT OVER THE AREA FOR
SUN NIGHT INTO MON. THE MAIN QUESTION WILL BE PRECIP TYPE. THE
EXPECTED SETUP IS TYPICALLY NOT CONDUCIVE FOR A WIDESPREAD FREEZING
RAIN WITH THE LACK OF NEUTRAL OR COLD ADVECTION UNDER THE SW
FLOW ALOFT. THE PROGRESSIVE NATURE OF THIS SYSTEM ALSO DOES NOT
FAVOR A WIDESPREAD FREEZING RAIN EPISODE. CURRENT THINKING IS THAT WE
COULD BE LOOKING AT AN ADVISORY TYPE EVENT WITH SNOW THE PREDOMINANT
PRECIP TYPE.
MEDIUM RANGE MODELS ARE FORECASTING ANOTHER SHORTWAVE TO KICK OF THE
ROCKIES ON TUE NIGHT INTO WED. HOWEVER THERE IS CONSIDERABLE
DIFFERENCES BETWEEN THE GFS AND ECMWF WITH REGARDS TO TIMING WITH
THE GFS MUCH MORE PROGRESSIVE.
&&
.FIRE WEATHER...
FIRE DANGER CONCERNS ARE EXPECTED TO REMAIN MINMAL FOR THE NEXT
COULE OF DAYS. RH`S ARE EXPECTED TO REMAIN ELEVATED FOR BOTH THU
AND FRI DUE TO TEMPS NOT CLIMBING MUCH ABOVE NORMAL. WINDS FOR THU
WILL TURN TO THE WEST AND SOUTHWEST BUT WILL REMAIN LIGHT...IN THE
8-11 MPH RANGE. A VERY STRONG COLD FRONT WILL PASS THROUGH THE
AREA ON FRI WITH WIND FLIPPING AROUND TO THE NORTH.
LAWSON
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION CONCERN/CHALLENGE WILL BE TIMING DISSIPATION OF LOW
CLOUDS. SOME HINTS ON VISIBLE SATELLITE THAT THIS IS ALREADY
TRYING TO OCCUR OVER WESTERN PORTIONS OF KS AND OK.
ADDITIONALLY...NAM/GFS MODELS BOTH CLEAR CLOUDS OUT THIS
AFTERNOON. HOWEVER...THINKING THE MORE PESSIMISTIC RUC MODEL HAS
THE BEST FORECAST...HOLDING LOW MVFR CIGS ACROSS THE AREA WELL
INTO THIS EVENING. THIS MAKES SENSE GIVEN INCREASING UPPER LEVEL
CLOUDS ALONG WITH WEAK BOUNDARY LAYER FLOW. IN FACT...WOULDN`T BE
SURPRISED IF MVFR CIGS HANG TOUGH ALL NIGHT...DUE TO WARM
ADVECTION INCREASING AND STRENGTHENING THE INVERSION. FOR
NOW...WENT LOW MVFR THROUGH 00Z THIS EVENING...AND THEN RAISED
EVERYONE UP ABOVE 2000 FT AGL...ALTHOUGH CIGS COULD REMAIN BELOW
2000 FT ALL NIGHT.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 24 47 25 38 / 0 10 10 0
HUTCHINSON 23 47 24 35 / 0 0 0 0
NEWTON 24 47 24 35 / 0 0 0 0
ELDORADO 24 47 25 37 / 0 0 10 0
WINFIELD-KWLD 25 49 28 41 / 0 10 10 10
RUSSELL 18 40 19 31 / 0 0 0 0
GREAT BEND 20 43 21 33 / 0 10 10 0
SALINA 22 43 22 33 / 0 0 0 0
MCPHERSON 23 46 23 34 / 0 0 0 0
COFFEYVILLE 27 49 33 43 / 0 10 10 10
CHANUTE 25 48 29 39 / 0 0 10 10
IOLA 24 48 28 38 / 0 0 0 10
PARSONS-KPPF 26 49 31 41 / 0 0 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1133 AM CST WED FEB 8 2012
...UPDATE TO AVIATION...
.DISCUSSION...
09Z WATER VAPOR SHOWS SEVERAL SHORTWAVE WITH ONE MOVING EAST OF THE
FORECAST AREA...A SECOND CLOSED CIRCULATION OVER MT...AND A THIRD
WAVE OFF THE SOUTHERN CA COAST. MEANWHILE SFC OBS SHOW A COLD SFC
RIDGE OF HIGH PRESSURE NOSING INTO CENTRAL KS.
FOR TODAY THROUGH THURSDAY...THE FORECAST AREA SHOULD REMAIN UNDER
THE INFLUENCE OF NORTHWEST FLOW WITH THE WAVE OVER MT EVENTUALLY
SHEARING OUT AND MOVING TO THE EAST. THE SFC RIDGE BUILDING INTO
CENTRAL KS NOW WILL LIMIT ANY DEEP MOISTURE SO THE FORECAST REMAINS
DRY. THE MOST UNCERTAIN PART OF THE FORECAST IS WITH THE LOW CLOUDS.
THE NAM AND RUC ARE SUGGESTING THE STRATUS COULD HANG AROUND FOR A
GOOD CHUNK OF THE DAY. SO WITH MOSTLY CLOUDY TO OVERCAST SKIES AND
CONTINUED COLD AIR ADVECTION...TODAY`S HIGHS WILL NOT WARM UP MUCH.
WE SHOULD SEE SOME RETURN FLOW AND SUNSHINE FOR THURSDAY AS THE SFC
RIDGE MOVES EAST OF THE AREA. THIS SHOULD ALLOW FOR HIGHS TO WARM
INTO THE 40S.
THURSDAY NIGHT WILL SEE PERHAPS THE STRONGEST COLD FRONT IN TERMS OF
COLD AIR SO FAR THIS WINTER...AS AN ARCTIC AIRMASS BUILDS SOUTH
THROUGH THE PLAINS FOR FRIDAY AND SATURDAY. THE MODEL CONSENSUS IS
FOR STRONG COLD AIR ADVECTION TO OCCUR BEHIND THE FRONT THROUGH
SATURDAY. TO MAKE THINGS WORSE...THE COLD AIR WILL BE MOVING OVER
THE SNOWPACK ACROSS CENTRAL NEB. SO HAVE LOWERED TEMPS FOR FRIDAY
AND SATURDAY. TEMPS ON SATURDAY ARE NOT EXPECTED TO MAKE IT OUT OF
THE 20S. THE MODELS ARE SHOWING SOME MID LEVEL FRONTOGENESIS ON THE
WESTERN EDGE OF THE UPPER TROUGH FOR FRIDAY NIGHT AND SATURDAY. THIS
FRONTOGENESIS IS COINCIDENTAL WITH A NARROW AXIS OF MID LEVEL
MOISTURE. THE GFS AND ECMWF TEND TO KEEP THIS BAND JUST TO THE WEST
OF THE FORECAST AREA SO HAVE NOT INCLUDED ANY POPS AT THIS TIME.
HOWEVER WILL MENTION A SLIGHT CHANCE FOR SOME FLURRIES IN PARTS OF
NORTH CENTRAL KS ON SATURDAY.
THE MAKINGS OF A WINTER STORM APPEAR TO BE COMING TOGETHER FOR
SUNDAY NIGHT INTO MONDAY MORNING. THE MEDIUM RANGE MODELS ARE IN
REASONABLE AGREEMENT THAT A SHORTWAVE WILL MOVE FROM THE PACIFIC
INTO THE PLAINS AS THE HIGH AMPLITUDE UPPER RIDGE OVER THE WEST
COAST BREAKS DOWN. BUFKIT SOUNDINGS SHOW THE COLUMN SATURATING WITH
ANY WARM NOSE DUE TO WARM AIR ADVECTION SUNDAY NIGHT INCREASING TO
ONLY ABOUT +1C. THIS SHOULD NOT BE ENOUGH TO MELT ANY SNOW
COMPLETELY...AND THINK THE PREDOMINANT PRECIP TYPE SHOULD BE SNOW.
HOWEVER THE MID LEVEL WARM AIR ADVECTION SHOULD BRING PLENTY OF
MOISTURE TO GO ALONG WITH THE REASONABLE FORCING OF THE UPPER WAVE.
BECAUSE OF THIS HAVE INCREASED POPS FOR SUNDAY NIGHT AND MONDAY. QPF
FORECASTS FROM THE ECMWF AND GFS SUGGEST THAT THERE COULD BE A
COUPLE INCHES OF SNOW...WHICH IS IN LINE WITH THE MODEST FORCING
PROVIDED BY THE OPEN WAVE. IF PRECIP HANGS ON LONG ENOUGH INTO THE
DAY MONDAY...WARM AIR ADVECTION MAY BE STRONG ENOUGH TO CAUSE THE
PRECIP TO CHANGE OVER TO LIQUID BY MONDAY AFTERNOON. WHILE THINGS
ARE FAR FROM CERTAIN...THIS SYSTEM BARES WATCHING AS IT GETS CLOSER.
THE MODELS PROG AN ACTIVE WEATHER PATTERN FOR NEXT WEEK AS A SECOND
WAVE LIFTS OUT INTO THE PLAINS ON TUESDAY. THERE SEEMS TO BE SOME
AGREEMENT IN THE TIMING OF THIS SECOND WAVE. ALTHOUGH THERE IS SOME
DISAGREEMENT IN THE TRACK OF THIS WAVE. REGARDLESS BOTH MODELS...
ESPECIALLY THE ECMWF WITH ITS NORTHERN TRACK...BRING ENOUGH WARM AIR
NORTH INTO EASTERN KS THAT PRECIP SHOULD BE ALL RAIN. IF THE SYSTEM
IS ABLE TO BRING ENOUGH WARM AIR NORTH...THERE COULD EVEN BE ENOUGH
INSTABILITY FOR SOME CONVECTION. AGAIN THIS WILL NEED TO BE WATCHED
IN LATER RUNS. AT THIS POINT...THE FORECAST HAS MODERATING TEMPS
INTO TUESDAY WITH A CHANCE FOR SOME RAIN.
WOLTERS
&&
.AVIATION...
MVFR CIGS ARE HOLDING STRONG OVER TAF SITES WITH ONLY A FEW
TEMPORARY BREAKS AT MHK THIS MORNING. SOME DRY AIR IS APPROACHING
THE TAF SITES WITH LOW POTENTIAL FOR ADDITIONAL BREAKS TO VFR IN
THE NEXT FEW HOURS. FEEL MVFR WILL BE PREDOMINANT THIS AFTERNOON
THOUGH WITH A SLOW RISE TO AROUND 2700 FT BY LATE AFTERNOON.
MOISTURE INCREASES OVERNIGHT WITH CIGS DROPPING CLOSER TO 1000 FT
BEFORE SUNRISE WITH SOME POTENTIAL FOR IFR BY SUNRISE. ANTICIPATE
CIGS HOLDING ON THROUGH THE ENTIRE TAF.
BARJENBRUCH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1132 AM CST WED FEB 8 2012
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION CONCERN/CHALLENGE WILL BE TIMING DISSIPATION OF LOW
CLOUDS. SOME HINTS ON VISIBLE SATELLITE THAT THIS IS ALREADY
TRYING TO OCCUR OVER WESTERN PORTIONS OF KS AND OK.
ADDITIONALLY...NAM/GFS MODELS BOTH CLEAR CLOUDS OUT THIS
AFTERNOON. HOWEVER...THINKING THE MORE PESSIMISTIC RUC MODEL HAS
THE BEST FORECAST...HOLDING LOW MVFR CIGS ACROSS THE AREA WELL
INTO THIS EVENING. THIS MAKES SENSE GIVEN INCREASING UPPER LEVEL
CLOUDS ALONG WITH WEAK BOUNDARY LAYER FLOW. IN FACT...WOULDN`T BE
SURPRISED IF MVFR CIGS HANG TOUGH ALL NIGHT...DUE TO WARM
ADVECTION INCREASING AND STRENGTHENING THE INVERSION. FOR
NOW...WENT LOW MVFR THROUGH 00Z THIS EVENING...AND THEN RAISED
EVERYONE UP ABOVE 2000 FT AGL...ALTHOUGH CIGS COULD REMAIN BELOW
2000 FT ALL NIGHT.
ADK
&&
.PREV DISCUSSION... /ISSUED 553 AM CST WED FEB 8 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
IFR AND MVFR CEILINGS WILL LINGER ACROSS THE AREA FOR A GOOD PORTION
OF THE DAY...AS LOW LEVEL MOISTURE REMAINS TRAPPED UNDER THE
SUBSIDENCE INVERSION FROM THE CANADIAN HIGH PRESSURE SETTLING ACROSS
THE PLAINS. NOT ALOT OF CONFIDENCE IN THIS STRATUS CLOUD DECK
CLEARING OUT UNTIL LATE THIS AFTERNOON...AS MAIN CLEARING WILL BE
EROSION OF THE CLOUDS BY BURNING IT OFF FROM THE SUNSHINE. EVEN AS
THE CLOUDS REMAIN TODAY...SHOULD SEE A GENERAL IMPROVING/LIFTING OF
THE CEILINGS TO ALL MVFR.
NOT ALOT OF CONFIDENCE ON TIMING OF THE CLEARING OF THE STRATUS DECK
TOWARDS THE LAST PORTION OF THE TAF FORECAST...BUT WILL TRY TO CLEAR
OUT LOW CLOUDS AFTER 00Z/THU. LOWEST CONFIDENCE IN THIS CLEARING
WILL BE OVER CEN KS...WHERE STRATUS WILL CLEAR OUR THIS EVENING.
KETCHAM
PREV DISCUSSION... /ISSUED 322 AM CST WED FEB 8 2012/
DISCUSSION...
MAIN FORECAST CHALLENGES INCLUDE TEMPERATURES FOR THE REMAINDER OF
THIS WEEK AND THE PRECIPITATION CHANCES FOR THE WEEKEND AND EARLY NEXT
WEEK.
SYNOPSIS:
THE UPPER LEVEL WEATHER SYSTEM IS MOVING EASTWARD OUT OF THE CENTRAL
PLAINS THIS MORNING. LOW STRATUS IS PRESENT ACROSS MUCH OF THE AREA
IN THE WAKE THE UPPER LEVEL SYSTEM. THE BLANKET OF CLOUDS HAS KEPT
TEMPERATURES WARMER DESPITE THE INFLUX OF HIGH PRESSURE.
TODAY - FRIDAY:
HIGH PRESSURE WILL DOMINATE THROUGH THIS PERIOD. SURFACE HIGH
PRESSURE IS BUILDING IN ACROSS KANSAS TODAY AND WILL SLIDE EASTWARD
OVERNIGHT. THE LOW STRATUS THAT IS CURRENTLY IMPACTING THE AREA IS
EXPECTED TO PERSIST THROUGH MUCH OF THE DAY TODAY. WHILE THIS HAS
KEPT OVERNIGHT TEMPERATURES WARMER THAN EXPECTED...THIS WILL KEEP
DAYTIME TEMPERATURES COOLER FOR TODAY. EXPECT HIGHS IN THE 30S
ACROSS MUCH OF KANSAS.
THERE WILL BE A QUICK PERIOD OF RETURN FLOW AND BRIEF WARM UP FOR
THURSDAY BEFORE A SECOND MORE POTENT CANADIAN HIGH PRESSURE SURGES
INTO THE REGION. THE NEXT COLD FRONT IS EXPECTED TO MOVE IN
THURSDAY NIGHT/EARLY FRIDAY WHICH WILL KNOCK TEMPERATURES BACK DOWN
BELOW NORMAL FOR FRIDAY.
BILLINGS
SATURDAY - TUESDAY:
ARCTIC AIRMASS STILL ON TRACK FOR THIS WEEKEND WITH A 1040MB SURFACE
HIGH PRESSURE MIGRATING SOUTH FROM CANADA. CONTINUING TO TREND
TEMPS DOWN SLIGHTLY SINCE THE PREVIOUSLY WARMER GFS HAS SHOWN HINTS
OF BRINGING THE COLDER AIR FARTHER WEST IN LINE WITH THE NAM AND EC.
THE FIRST IN A SERIES OF SHORTWAVES APPROACHES FROM THE FOUR CORNERS
AREA LATE SUNDAY NIGHT INTO MONDAY. WITH THE ARCTIC AIRMASS IN
PLACE PRECIPITATION SHOULD START AS ALL SNOW SUNDAY NIGHT...BUT AS THE
SURFACE HIGH PRESSURE MOVES EAST...SOUTHERLY FLOW WILL CAUSE
MID-LEVEL WARM ADVECTION AND WILL SUPPORT A CHANGEOVER TO A MIX OF
RAIN AND SNOW FOR MONDAY MORNING INTO THE EARLY AFTERNOON.
SECOND...AND SLIGHTLY MORE POTENT SHORTWAVE TROUGH FOLLOWS QUICKLY
ON THE HEELS OF THE FIRST...EJECTING INTO THE SOUTHERN PLAINS
TUESDAY EVENING. LEE CYCLOGENESIS PULLS LOW TO MID 40 DEWPOINTS
INTO THE AREA ALONG WITH WARMER LOW AND MID LEVEL TEMPERATURES. THE EC
FORECAST SOUNDING IS SLIGHTLY COOLER THAN THE GFS...BUT HOVERS
AROUND FREEZING THROUGH THE LOW LEVELS...AND ALSO WARMS UP THROUGHOUT
THE PERIOD. THE RESULT WOULD BE MAINLY RAIN FOR THE CWA WITH ANY
SNOWFLAKES MIXING IN CONFINED TO NORTHERN KANSAS.
ARL
FIRE WEATHER...
VERY LITTLE IN THE WAY OF FIRE WEATHER CONCERNS THROUGH THE FORECAST
WITH COOL AIR BEING THE MAIN THEME FOR THIS WEEK AND THE WEEKEND.
AFTER YESTERDAYS COLD FRONT ANOTHER MORE POTENT COLD FRONT WILL
SURGE IN ON THURSDAY NIGHT/FRIDAY. WINDS WILL REMAIN LIGHT AND
RELATIVE HUMIDITIES HIGH.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 36 23 49 24 / 0 0 0 10
HUTCHINSON 34 22 47 23 / 0 0 0 0
NEWTON 34 23 46 23 / 0 0 0 0
ELDORADO 36 22 48 24 / 0 0 0 10
WINFIELD-KWLD 38 23 49 27 / 0 0 10 10
RUSSELL 31 20 42 19 / 0 0 0 0
GREAT BEND 32 20 45 20 / 0 0 10 10
SALINA 33 21 46 21 / 0 0 0 0
MCPHERSON 33 22 46 22 / 0 0 0 0
COFFEYVILLE 40 23 49 30 / 0 0 10 10
CHANUTE 37 22 49 27 / 0 0 0 0
IOLA 37 22 48 27 / 0 0 0 0
PARSONS-KPPF 38 23 49 28 / 0 0 0 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
540 AM CST WED FEB 8 2012
...UPDATE TO AVIATION...
.DISCUSSION...
09Z WATER VAPOR SHOWS SEVERAL SHORTWAVE WITH ONE MOVING EAST OF THE
FORECAST AREA...A SECOND CLOSED CIRCULATION OVER MT...AND A THIRD
WAVE OFF THE SOUTHERN CA COAST. MEANWHILE SFC OBS SHOW A COLD SFC
RIDGE OF HIGH PRESSURE NOSING INTO CENTRAL KS.
FOR TODAY THROUGH THURSDAY...THE FORECAST AREA SHOULD REMAIN UNDER
THE INFLUENCE OF NORTHWEST FLOW WITH THE WAVE OVER MT EVENTUALLY
SHEARING OUT AND MOVING TO THE EAST. THE SFC RIDGE BUILDING INTO
CENTRAL KS NOW WILL LIMIT ANY DEEP MOISTURE SO THE FORECAST REMAINS
DRY. THE MOST UNCERTAIN PART OF THE FORECAST IS WITH THE LOW CLOUDS.
THE NAM AND RUC ARE SUGGESTING THE STRATUS COULD HANG AROUND FOR A
GOOD CHUNK OF THE DAY. SO WITH MOSTLY CLOUDY TO OVERCAST SKIES AND
CONTINUED COLD AIR ADVECTION...TODAY`S HIGHS WILL NOT WARM UP MUCH.
WE SHOULD SEE SOME RETURN FLOW AND SUNSHINE FOR THURSDAY AS THE SFC
RIDGE MOVES EAST OF THE AREA. THIS SHOULD ALLOW FOR HIGHS TO WARM
INTO THE 40S.
THURSDAY NIGHT WILL SEE PERHAPS THE STRONGEST COLD FRONT IN TERMS OF
COLD AIR SO FAR THIS WINTER...AS AN ARCTIC AIRMASS BUILDS SOUTH
THROUGH THE PLAINS FOR FRIDAY AND SATURDAY. THE MODEL CONSENSUS IS
FOR STRONG COLD AIR ADVECTION TO OCCUR BEHIND THE FRONT THROUGH
SATURDAY. TO MAKE THINGS WORSE...THE COLD AIR WILL BE MOVING OVER
THE SNOWPACK ACROSS CENTRAL NEB. SO HAVE LOWERED TEMPS FOR FRIDAY
AND SATURDAY. TEMPS ON SATURDAY ARE NOT EXPECTED TO MAKE IT OUT OF
THE 20S. THE MODELS ARE SHOWING SOME MID LEVEL FRONTOGENESIS ON THE
WESTERN EDGE OF THE UPPER TROUGH FOR FRIDAY NIGHT AND SATURDAY. THIS
FRONTOGENESIS IS COINCIDENTAL WITH A NARROW AXIS OF MID LEVEL
MOISTURE. THE GFS AND ECMWF TEND TO KEEP THIS BAND JUST TO THE WEST
OF THE FORECAST AREA SO HAVE NOT INCLUDED ANY POPS AT THIS TIME.
HOWEVER WILL MENTION A SLIGHT CHANCE FOR SOME FLURRIES IN PARTS OF
NORTH CENTRAL KS ON SATURDAY.
THE MAKINGS OF A WINTER STORM APPEAR TO BE COMING TOGETHER FOR
SUNDAY NIGHT INTO MONDAY MORNING. THE MEDIUM RANGE MODELS ARE IN
REASONABLE AGREEMENT THAT A SHORTWAVE WILL MOVE FROM THE PACIFIC
INTO THE PLAINS AS THE HIGH AMPLITUDE UPPER RIDGE OVER THE WEST
COAST BREAKS DOWN. BUFKIT SOUNDINGS SHOW THE COLUMN SATURATING WITH
ANY WARM NOSE DUE TO WARM AIR ADVECTION SUNDAY NIGHT INCREASING TO
ONLY ABOUT +1C. THIS SHOULD NOT BE ENOUGH TO MELT ANY SNOW
COMPLETELY...AND THINK THE PREDOMINANT PRECIP TYPE SHOULD BE SNOW.
HOWEVER THE MID LEVEL WARM AIR ADVECTION SHOULD BRING PLENTY OF
MOISTURE TO GO ALONG WITH THE REASONABLE FORCING OF THE UPPER WAVE.
BECAUSE OF THIS HAVE INCREASED POPS FOR SUNDAY NIGHT AND MONDAY. QPF
FORECASTS FROM THE ECMWF AND GFS SUGGEST THAT THERE COULD BE A
COUPLE INCHES OF SNOW...WHICH IS IN LINE WITH THE MODEST FORCING
PROVIDED BY THE OPEN WAVE. IF PRECIP HANGS ON LONG ENOUGH INTO THE
DAY MONDAY...WARM AIR ADVECTION MAY BE STRONG ENOUGH TO CAUSE THE
PRECIP TO CHANGE OVER TO LIQUID BY MONDAY AFTERNOON. WHILE THINGS
ARE FAR FROM CERTAIN...THIS SYSTEM BARES WATCHING AS IT GETS CLOSER.
THE MODELS PROG AN ACTIVE WEATHER PATTERN FOR NEXT WEEK AS A SECOND
WAVE LIFTS OUT INTO THE PLAINS ON TUESDAY. THERE SEEMS TO BE SOME
AGREEMENT IN THE TIMING OF THIS SECOND WAVE. ALTHOUGH THERE IS SOME
DISAGREEMENT IN THE TRACK OF THIS WAVE. REGARDLESS BOTH MODELS...
ESPECIALLY THE ECMWF WITH ITS NORTHERN TRACK...BRING ENOUGH WARM AIR
NORTH INTO EASTERN KS THAT PRECIP SHOULD BE ALL RAIN. IF THE SYSTEM
IS ABLE TO BRING ENOUGH WARM AIR NORTH...THERE COULD EVEN BE ENOUGH
INSTABILITY FOR SOME CONVECTION. AGAIN THIS WILL NEED TO BE WATCHED
IN LATER RUNS. AT THIS POINT...THE FORECAST HAS MODERATING TEMPS
INTO TUESDAY WITH A CHANCE FOR SOME RAIN.
WOLTERS
&&
.AVIATION...
MVFR STRATUS WILL LINGER ACROSS ALL OF THE TERMINALS THROUGH
18Z AS SFC RIDGE SLIDES EASTWARD WITH DECREASING NORTH/NORTHWEST
WINDS. ALTHOUGH CEILINGS ARE EXPECTED TO GRADUALLY INCREASE TO
VFR BY 21Z-23Z TIME FRAME...FEEL THE COMBINATION OF RESIDUAL
MOISTURE LAYER NEAR AND JUST ABOVE 900MB WITHIN AREA OF WEAK
MIXING MAY BE ENOUGH TO ALLOW FOR STRATOCU DECK AROUND 3500 FT TO
LINGER THRU MUCH OF THE REMAINDER OF THE TAF FORECAST. AS A
RESULT...SFC WINDS WILL BE LIGHT AND VARIABLE.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
321 AM CST WED FEB 8 2012
...ARCTIC AIR TO INTRUDE ON THE REGION THIS WEEKEND...
.DISCUSSION...
09Z WATER VAPOR SHOWS SEVERAL SHORTWAVE WITH ONE MOVING EAST OF THE
FORECAST AREA...A SECOND CLOSED CIRCULATION OVER MT...AND A THIRD
WAVE OFF THE SOUTHERN CA COAST. MEANWHILE SFC OBS SHOW A COLD SFC
RIDGE OF HIGH PRESSURE NOSING INTO CENTRAL KS.
FOR TODAY THROUGH THURSDAY...THE FORECAST AREA SHOULD REMAIN UNDER
THE INFLUENCE OF NORTHWEST FLOW WITH THE WAVE OVER MT EVENTUALLY
SHEARING OUT AND MOVING TO THE EAST. THE SFC RIDGE BUILDING INTO
CENTRAL KS NOW WILL LIMIT ANY DEEP MOISTURE SO THE FORECAST REMAINS
DRY. THE MOST UNCERTAIN PART OF THE FORECAST IS WITH THE LOW CLOUDS.
THE NAM AND RUC ARE SUGGESTING THE STRATUS COULD HANG AROUND FOR A
GOOD CHUNK OF THE DAY. SO WITH MOSTLY CLOUDY TO OVERCAST SKIES AND
CONTINUED COLD AIR ADVECTION...TODAY`S HIGHS WILL NOT WARM UP MUCH.
WE SHOULD SEE SOME RETURN FLOW AND SUNSHINE FOR THURSDAY AS THE SFC
RIDGE MOVES EAST OF THE AREA. THIS SHOULD ALLOW FOR HIGHS TO WARM
INTO THE 40S.
THURSDAY NIGHT WILL SEE PERHAPS THE STRONGEST COLD FRONT IN TERMS OF
COLD AIR SO FAR THIS WINTER...AS AN ARCTIC AIRMASS BUILDS SOUTH
THROUGH THE PLAINS FOR FRIDAY AND SATURDAY. THE MODEL CONSENSUS IS
FOR STRONG COLD AIR ADVECTION TO OCCUR BEHIND THE FRONT THROUGH
SATURDAY. TO MAKE THINGS WORSE...THE COLD AIR WILL BE MOVING OVER
THE SNOWPACK ACROSS CENTRAL NEB. SO HAVE LOWERED TEMPS FOR FRIDAY
AND SATURDAY. TEMPS ON SATURDAY ARE NOT EXPECTED TO MAKE IT OUT OF
THE 20S. THE MODELS ARE SHOWING SOME MID LEVEL FRONTOGENESIS ON THE
WESTERN EDGE OF THE UPPER TROUGH FOR FRIDAY NIGHT AND SATURDAY. THIS
FRONTOGENESIS IS COINCIDENTAL WITH A NARROW AXIS OF MID LEVEL
MOISTURE. THE GFS AND ECMWF TEND TO KEEP THIS BAND JUST TO THE WEST
OF THE FORECAST AREA SO HAVE NOT INCLUDED ANY POPS AT THIS TIME.
HOWEVER WILL MENTION A SLIGHT CHANCE FOR SOME FLURRIES IN PARTS OF
NORTH CENTRAL KS ON SATURDAY.
THE MAKINGS OF A WINTER STORM APPEAR TO BE COMING TOGETHER FOR
SUNDAY NIGHT INTO MONDAY MORNING. THE MEDIUM RANGE MODELS ARE IN
REASONABLE AGREEMENT THAT A SHORTWAVE WILL MOVE FROM THE PACIFIC
INTO THE PLAINS AS THE HIGH AMPLITUDE UPPER RIDGE OVER THE WEST
COAST BREAKS DOWN. BUFKIT SOUNDINGS SHOW THE COLUMN SATURATING WITH
ANY WARM NOSE DUE TO WARM AIR ADVECTION SUNDAY NIGHT INCREASING TO
ONLY ABOUT +1C. THIS SHOULD NOT BE ENOUGH TO MELT ANY SNOW
COMPLETELY...AND THINK THE PREDOMINANT PRECIP TYPE SHOULD BE SNOW.
HOWEVER THE MID LEVEL WARM AIR ADVECTION SHOULD BRING PLENTY OF
MOISTURE TO GO ALONG WITH THE REASONABLE FORCING OF THE UPPER WAVE.
BECAUSE OF THIS HAVE INCREASED POPS FOR SUNDAY NIGHT AND MONDAY. QPF
FORECASTS FROM THE ECMWF AND GFS SUGGEST THAT THERE COULD BE A
COUPLE INCHES OF SNOW...WHICH IS IN LINE WITH THE MODEST FORCING
PROVIDED BY THE OPEN WAVE. IF PRECIP HANGS ON LONG ENOUGH INTO THE
DAY MONDAY...WARM AIR ADVECTION MAY BE STRONG ENOUGH TO CAUSE THE
PRECIP TO CHANGE OVER TO LIQUID BY MONDAY AFTERNOON. WHILE THINGS
ARE FAR FROM CERTAIN...THIS SYSTEM BARES WATCHING AS IT GETS CLOSER.
THE MODELS PROG AN ACTIVE WEATHER PATTERN FOR NEXT WEEK AS A SECOND
WAVE LIFTS OUT INTO THE PLAINS ON TUESDAY. THERE SEEMS TO BE SOME
AGREEMENT IN THE TIMING OF THIS SECOND WAVE. ALTHOUGH THERE IS SOME
DISAGREEMENT IN THE TRACK OF THIS WAVE. REGARDLESS BOTH MODELS...
ESPECIALLY THE ECMWF WITH ITS NORTHERN TRACK...BRING ENOUGH WARM AIR
NORTH INTO EASTERN KS THAT PRECIP SHOULD BE ALL RAIN. IF THE SYSTEM
IS ABLE TO BRING ENOUGH WARM AIR NORTH...THERE COULD EVEN BE ENOUGH
INSTABILITY FOR SOME CONVECTION. AGAIN THIS WILL NEED TO BE WATCHED
IN LATER RUNS. AT THIS POINT...THE FORECAST HAS MODERATING TEMPS
INTO TUESDAY WITH A CHANCE FOR SOME RAIN.
WOLTERS
&&
.AVIATION...
CEILING HEIGHTS ARE THE MAIN CHALLENGE FOR THIS FORECAST. HEIGHTS
LIKELY TO BE ON THE IFR/MVFR THRESHOLD THROUGH 12Z. SINKING MOTION
BEHIND UPPER TROF AND BUILDING LOW LEVEL HIGH PRESSURE TO COUNTERACT
WET LOW LEVELS AIDED BY EVENING PRECIPITATION. WILL TEMPO IFR LEVELS
FOR THE FIRST FEW HOURS...BUT MODELS SUGGEST THE FORMER PROCESS
SHOULD TAKE OVER THEREAFTER. TRANSITION FROM MVFR TO VFR CONDITIONS
ALSO UNCERTAIN...BUT LATEST PROGS QUICKER AND WILL TREND THAT WAY.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
951 PM MST TUE FEB 7 2012
.UPDATE...
741 PM MST TUE FEB 7 2012
JUST COMPLETED AN UPDATE. SATELLITE SHOWING CLOUD COVER IS SLOW TO
ERODE. AREA 00Z SOUNDINGS SHOW A STRONG INVERSION WITH WARMING
ALOFT EXPECTED DURING THE NIGHT. SO SLOWED THE CLEARING PROCESS
AND WARMED MINS ACCORDINGLY BASED ON REALITY AND LATEST MODEL
TRENDS. RUC LOOKS TO BE HANDLING THE BOUNDARY LAYER RH THE BEST AT
THIS TIME. ALSO BASED ON THE 00Z SOUNDINGS AND LATEST
RUC...HRRR...AND NAM SHOWING REDUCED VISIBILITIES IN THE SAME
PLACE...DECIDED TO ADD PATCHY FREEZING FOG INTO THE NORTHWEST HALF
TO TWO-THIRDS.
BULLER
&&
.DISCUSSION...
245 PM MST TUE FEB 7 2012
TONIGHT...PRIMARY FORECAST CONCERN WILL BE HOW COLD OVERNIGHT LOW
TEMPERATURES WILL DROP AND HOW QUICKLY CLOUDS WILL CLEAR THIS
EVENING...AND THE DEVELOPMENT OF FOG. IF CLOUDS LINGER OR FOG
DEVELOPS ACROSS THE AREA...CURRENT OVERNIGHT LOW TEMPERATURES MAY BE
TOO COLD. IF SKIES CLEAR COMPLETELY ALLOWING FOR MAXIMUM RADIATIONAL
COOLING...TEMPERATURES MAY BE TOO WARM.
CURRENT WV SATELLITE IMAGERY SHOWS UPPER LEVEL TROUGH MOVING ACROSS
THE CENTRAL CONUS WITH A SURGE OF COLD AIR MOVING DOWN OUT OF CANADA
INTO THE NORTHERN PLAINS. A FEW FLURRIES MAY STILL BE POSSIBLE LATE
THIS AFTERNOON BUT WILL END BY THIS EVENING. SUBSIDENCE WILL QUICKLY
MOVE INTO WESTERN AND CENTRAL KANSAS OVERNIGHT BEHIND THE DEPARTING
SYSTEM...DROPPING TEMPERATURES INTO THE SINGLE DIGITS ACROSS ALL BUT
THE SOUTHERN PERIPHERY OF THE CWA. GIVEN LIGHT WINDS AND SUFFICIENT
LOW LEVEL MOISTURE...THERE IS A CHANCE OF PATCHY FOG DEVELOPING
ACROSS AT LEAST THE NORTHERN HALF OF THE CWA. HOWEVER...CONFIDENCE
NOT HIGH ENOUGH WITH CURRENT CLOUD COVER SLOW TO EXIT AND MAY LIMIT
RADIATIONAL COOLING.
PMM
WEDNESDAY-FRIDAY...DRY WITH WARMING TEMPERATURES WEDNESDAY AND
THURSDAY. A BACKDOOR FRONT MOVES IN FROM THE NORTH/NORTHEAST
FRIDAY LEADING TO COLDER TEMPERATURES...ESPECIALLY ACROSS THE
EAST/NORTHEAST. OVERNIGHT LOWS WILL CONTINUE TO BE COLD IN SNOW
PACK AREAS WHERE SINGLE DIGITS EXPECTED...FURTHER SOUTH OUT OF THE
SNOW PACK TEENS TO LOW 20S EXPECTED.
FRIDAY NIGHT-SATURDAY...UPPER LEVEL DISTURBANCE AIDED BY
FAVORABLE POSITION TO JET STREAK MOVES INTO THE AREA WITH BEST
MOISTURE AND LIFT FAVORING THE NORTHEAST 1/2-1/3 OF THE AREA FOR
SOME LIGHT SNOW. HIGH TEMPERATURES GENERALLY IN THE 30S...WARMEST
ACROSS THE SOUTHWEST PART OF THE AREA.
SATURDAY NIGHT-SUNDAY NIGHT...UPPER TROUGH MOVES ACROSS THE AREA
DURING THE PERIOD PRODUCING SOME SNOW. DIFFERENCES IN THE SPEED
AND INTENSITY OF THE TROUGH PREVENT GETTING TOO DETAILED AT
PRESENT TIME BUT CANT RULE OUT SOME ACCUMULATING SNOW. BEST TIME
WOULD BE SUNDAY-SUNDAY NIGHT. HIGH TEMPERATURES SUNDAY IN THE 30S.
MONDAY...SHOULD SEE A DRY DAY WITH HIGHS IN THE UPPER 30S TO MID
40S (EAST TO WEST). HOWEVER...POSSIBLE SNOW COVER FROM SATURDAY
NIGHT-SUNDAY NIGHT SYSTEM COULD MAKE CURRENT FORECAST HIGHS
OPTIMISTIC.
MONDAY NIGHT-TUESDAY...ANOTHER IN A SERIES OF UPPER LOWS/TROUGHS
MOVES ACROSS THE AREA. LIGHT RAIN AND/OR LIGHT SNOW EXPECTED.
007
&&
.AVIATION...
951 PM MST TUE FEB 7 2012
FOR THE 06Z TAFS...CONCERNS FOR THIS PERIOD WILL BE CIGS/VIS AT
BOTH LOCATIONS. CURRENTLY...WIDESPREAD STRATUS HAS BLANKETED THE
AREA. FOR KGLD...BELIEVE BACK EDGE OF STRATUS WILL CLEAR TERMINAL
BRIEFLY ALLOWING TEMPERATURES TO FALL. THIS WILL ALLOW CIGS TO
REDEVLOP AT THE TERMINAL WHICH WILL BE IN THE IFR RANGE. THESE
CIGS WILL LIFT THROUGH THE MORNING HOURS AND SCATTER OUT BY EARLY
AFTERNOON. FOR KMCK...TERMINAL WILL STAY UNDER MVFR CIGS THROUGH
THE NIGHT AND INTO THE DAY ON WEDNESDAY. WINDS WILL SWITCH TO THE
SOUTH AT BOTH LOCATIONS AS SURFACE HIGH PRESSURE MOVES OFF TO THE
EAST.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...
/TONIGHT THROUGH WEDNESDAY NIGHT/
A COMPLICATED FORECAST TONIGHT THROUGH WEDNESDAY NIGHT. THE MODELS
ARE IN GOOD AGREEMENT THAT A FAIRLY PROGRESSIVE CLIPPER SYSTEM WILL
MAKE ITS WAY ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS FROM AROUND
DAWN TOMORROW THROUGH LATE TOMORROW NIGHT. THE NAM12 AND GFS MODELS
WERE RELIED UPON HEAVILY TO CONSTRUCT THE FORECAST FOR THE PERIOD
TONIGHT THROUGH TOMORROW NIGHT. THE MODEL PLAN VIEWS ARE ALL
SUGGESTING THE POSSIBILITY OF AN ALL SNOW EVENT...HOWEVER...THE
CORRESPONDING TIME HEIGHT CROSS SECTIONS AND SOUNDINGS ARE PAINTING A
MORE MUDDLED PICTURE. THE TIME HEIGHTS AND SOUNDINGS ARE SHOWING A
LAYER OF SURFACE AIR 2-4 DEGREES ABOVE FREEZING OVERNIGHT INTO EARLY
TOMORROW...WHICH WOULD MAKE IT DIFFICULT FOR THE PASSING CLIPPER TO
PRODUCE ALL SNOW. BASED ON THESE DATA A RAIN/SNOW MIX SEEMS MOST
LIKELY FOR MOST OF THE FORECAST AREA AFTER DAWN TOMORROW THROUGH
ABOUT MID MORNING...AS IT APPEARS A GOOD DEAL OF THE SNOW WILL MELT
BEFORE IT CAN REACH THE SURFACE. THE EXCEPTIONS WOULD BE AREAS ALONG
AND NORTH OF THE I64 CORRIDOR...WHERE SUBFREEZING AIR WILL LIKELY BE
PRESENT...AND THE HIGHER ELEVATIONS ABOVE 2000 FEET ALONG THE
VIRGINIA AND WEST VIRGINIA BORDERS. THE NORTHWEST COUNTIES COULD SEE
LIGHT ACCUMULATIONS OF SNOW EARLY TOMORROW ON GRASSY AREAS AND
ELEVATED SURFACES...WITH LESS THAN AN INCH OF ACCUMULATION EXPECTED.
WITH ROAD SURFACES AS WARM AS THEY ARE ACROSS EASTERN KENTUCKY...IT
DOES NOT APPEAR LIKELY THAT ANY SNOW WILL BE ABLE TO ACCUMULATE ON
THE ROADS. HOWEVER...IF TEMPERATURES DROP EVEN A COUPLE OF DEGREES
COOLER AREA WIDE THAN 4 PM FORECAST IS GOING BE DEPICTING...MORE
WIDESPREAD LIGHT SNOW ACCUMULATIONS COULD OCCUR. FOR NOW...DUE TO THE
AMOUNT UNCERTAINTY INVOLVED...DECIDED TO GO WITH ONLY A RAIN SNOW MIX
FOR NOW. ALSO INCREASED THE LIKELIHOOD OF PRECIPITATION TOMORROW...AS
THE MODELS ARE PRODUCING ENOUGH QPF TO WARRANT HAVING HIGHER
PRECIPITATION PROBABILITIES THAN THE LATEST GUIDANCE IS SUGGESTING.
WILL ISSUE A SPECIAL WEATHER STATEMENT LATER IN THE SHIFT TO ADDRESS
THE TYPE OF PRECIP EXPECTED LATER TONIGHT AND EARLY TOMORROW.
THE ONE MAJOR CHANGE MADE TO THE FORECAST WAS TO SLOW DOWN THE
EASTWARD PROGRESSION OF THE AFOREMENTIONED CLIPPER SYSTEM...AS
TEMPERATURES ALOFT ARE NOT NEARLY AS COLD AS THEY USUALLY ARE THIS
TIME OF YEAR AND WINDS ALOFT ARE NOT NEARLY AS STRONG AS THEY USUALLY
ARE. THEREFORE...THE CLIPPER SYSTEM LIKELY WONT HAVE QUITE AS MUCH
FORWARD SPEED AS THE INHERITED FORECAST WAS SUGGESTING. THAT BEING
SAID...THE TIMING OF PRECIPITATION ONSET AND PROGRESSION ACROSS THE
FORECAST WERE UPDATED TO REFLECT THE SLOWER TIMING OF THE
CLIPPER...BY ROUGHLY 5 OR 6 HOURS. THE CORRESPONDING SKY
COVER...WEATHER...AND QPF GRIDS WERE ALSO UPDATED TO REFLECT THE
SLOWER TIMING. THE QPF FORECAST WAS BASED ON A COMBINATION OF THE
LATEST HPC GUIDANCE AND WWD SNOWFALL FORECAST. THE WWD FORECAST
GRAPHIC WAS IN GOOD AGREEMENT WITH WHERE THE NEW FORECAST IS
SUGGESTING SNOW WILL FALL...SO THAT SEEMED LIKE A SOUND BASIS FOR THE
SNOW FORECAST FOR TOMORROW.
AS FOR TEMPERATURES...WENT PRETTY CLOSE TO THE COOLER METMOS LOWS FOR
TONIGHTS MINIMUM TEMPS...AND SLIGHTLY COOLER THAN MOS FOR TOMORROWS
HIGHS...AS CLOUD COVER SHOULD EFFECTIVELY KEEP TEMPERATURES FROM
RISING TO THE NUMBERS SUGGESTED BY THE MAV/METMOS DATA. DEWPOINTS AND
WINDS WERE ADJUSTED A BIT TOO...BUT ONLY SMALL CHANGES WERE NEEDED.
.LONG TERM.../THURSDAY THROUGH TUESDAY/
HIGH PRESSURE OVER THE REGION WELL DEPICTED IN ALL MODELS. A COLD
TROF DROPS OUT OF CANADA BY FRIDAY MORNING AS THE HIGH PRESSURE
EASES OFF THE CAROLINA COAST. THIS TROF ACCOMPANIED BY A SFC COLD
FRONT THAT LOOKS TO RADICALLY CHANGE THE TEMPERATURE PATTERN ACROSS
THE OH/TN RIVER VALLEYS THIS WEEKEND. BOTH THE 12Z GFS AND ECMWF
INDICATE A RETURN FLOW OF MOISTURE UP THRU THE SRN PLAINS EVEN AS
THE FRONT PICKS UP MOISTURE AS IT TRACKS ACROSS THE GREAT LAKES. BY
FRI EVENING THE COLD FRONT TAPS INTO THE ADDITIONAL MOISTURE TO DROP
SOME PCPN OVER ERN KY. THE ECMWF IS MORE AGGRESSIVE WITH THE PCPN.
HAVE CHOSEN TO BLEND THE 2 MODELS WHICH BRINGS PCPN FOR THE ENTIRE
CWFA LATE FRI INTO SAT. TEMPS WILL INITIALLY START OUT WARM ENUF FOR
ALL RAIN BUT WILL SEE A MIX AND THEN ALL SNOW BY EARLY SAT MORNING.
SNOW WILL LINGER INTO THE DAY ON SAT FOR OUR MTN COUNTIES IN THE
EAST WHICH COULD BRING TOTAL SNOW FALL FOR THIS EVENT TO AROUND 1/2
INCH IN THE MTNS...ESP ABOVE 2K FEET...WHILE THE POSSIBILITY OF
ACCUMULATING SNOW EXISTS FOR THE REMAINDER OF THE FCST AREA BUT
GENERALLY A TENTH OF AN INCH OR LESS. HIGH TEMPS ON FRI BEFORE THE
FRONT WILL CLIMB INTO THE MID 40S BUT WILL PLUNGE INTO THE MID 30S
FOR BOTH SAT/SUN WITH SAT NITE LOWS IN THE MID TEENS. HIGH PRESSURE
WILL BRING A WARMING TREND TO THE EARLY WORK WEEK WITH MID 40S FOR
MON AND NEAR 50 BY TUE. EXPECT AN INCREASE IN CLOUDS BY TUE AFTN AS
THE NEXT COLD FRONT...MAINLY A GLANCING BLOW...SWEEPS ACROSS THE
GREAT LAKES AS A SFC REFLECTION OF THE NEXT SHORT WAVE TO ROTATE
AROUND THE SEMI PERMANENT HUDSON BAY VORTEX.
&&
.AVIATION.../06Z TO 06Z/...UPDATED
VFR CONDITIONS WILL LAST THROUGH MOST OF THE NIGHT. THIS WILL BE
FOLLOWED BY A RAPID DETERIORATION BETWEEN ABOUT 10Z AND 14Z...
WITH LIGHT PRECIPITATION AND MVFR DEVELOPING. MVFR AND LOCALIZED IFR
WILL THEN LAST THROUGH THE DAY. A PERIOD OF STEADY PRECIPITATION IS
MOST LIKELY TO OCCUR N AND E OF A LINE FROM KSME TO KLOZ TO
K1A6...WITH THE STEADY PRECIPITATION TAPERING TO SCATTERED SHOWERS
FROM WEST TO EAST BETWEEN 15Z AND 21Z. ANY PRECIPITATION SW OF THE
KSME-KLOZ-K1A6 LINE IS MORE LIKELY TO REMAIN SPORADIC. WHERE
PRECIPITATION STARTS EARLY IN THE MORNING...IT IS LIKELY TO BEGIN AS
SNOW. HOWEVER...AS TEMPERATURES WARM...A MIX OF RAIN AND SNOW IS
EXPECTED LATER IN THE DAY. PRECIPITATION LOOKS TO END FROM WEST TO
EAST BY AROUND 00Z WITH LOW CIGS LINGERING IN THE M/VFR RANGE THROUGH
THE REMAINDER OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...AR/HAL
LONG TERM....DUSTY
AVIATION...HAL/MB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1236 PM EST WED FEB 8 2012
.SYNOPSIS...
AN UPPER LEVEL SYSTEM WILL BRING WIDESPREAD SNOW SHOWERS TO THE
AREA TODAY. HIGH PRESSURE WILL BRING SEASONABLE TEMPERATURES AND
DRY CONDITIONS ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UL WAVE IS SWINGING THROUGH THE UPPER OHIO VALLEY, AHEAD OF THE
MAIN TROUGH. THIS WAVE WILL MOVE THROUGH VERY QUICKLY...ENDING THE
SNOW FROM WEST TO EAST LATE THIS AFTERNOON.
CONFIDENT THAT THE HIGHEST AMOUNTS OF SNOW WILL BE 2 TO 4 INCHES
ACROSS THE RIDGE TOPS. ADVISORY CONTINUES FOR THE RIDGE COUNTIES
THROUGH THIS EVENING.
ELSEWHERE, A GENERAL 1 TO 2 WILL COVER MOST PLACES. ACCUMULATIONS
WILL BE LIMITED BY THE SPEED AT WHICH THIS SYSTEM WILL MOVE
THROUGH AND THAT MOST SFC TEMPS WILL RISE SLIGHTLY ABOVE FREEZING
TODAY, WITH THE EXCEPTION OF THE RIDGE TOPS.
TEMPERATURES ARE BLEND OF THE LATEST RUN OF THE HRRR AND 12Z NAM.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
SNOW SHOWERS ARE EXPECTED OVER THE SOUTHEAST RIDGES THIS EVENING,
WITH AN ADDITIONAL ACCUMULATION AROUND AN INCH POSSIBLE.
DRY HIGH PRESSURE WILL THEN BRING NEAR NORMAL TEMPERATURES INTO
FRIDAY.
FOR FRIDAY, MODELS CONTINUE TO HAVE TIMING ISSUES WITH ARCTIC
FRONT APPROACHING. HAVE GONE MIDDLE OF THE ROAD WITH HIGH CHANCE
TO LIKELY POPS LATE IN THE AFTERNOON. EXPECT A RAIN AND SNOW MIX
IN THE FAR SOUTH WITH SNOW ELSEWHERE. WILL PROBABLY AGAIN HAVE TO
DEAL WITH LIGHT ACCUMULATIONS. BUT WITH THIS SYSTEM, IT APPEARS
THE HIGHER ACCUMULATIONS WILL BE ACROSS THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LATEST ECMWF AND GFS MODEL RUNS CONTINUE TO SHOW A DEEP UPPER TROUGH
PLUNGING ACROSS EASTERN CANADA DURING THE WEEKEND. 00Z ECMWF
INDICATES A SURFACE WAVE DEVELOPING ALONG THE BOUNDARY WHICH WOULD
TEND TO SLOW DOWN EASTWARD PROGRESS FRIDAY NIGHT...AND WOULD
LENGTHEN DURATION OF PRECIPITATION INTO SATURDAY. REGARDLESS OF
TIMING...VERY COLD CYCLONIC FLOW BEHIND THE SYSTEM SHOULD MAINTAIN
SCATTERED SNOW SHOWERS OVER THE REGION THROUGH SATURDAY.
STRONG SURFACE HIGH IS PROGGED TO BUILD SOUTHEASTWARD INTO THE MS
VALLEY BY SUNDAY AND THEN SLIDE EAST TO THE ATLANTIC COAST BY
TUESDAY. TEMPERATURES ARE FORECAST TO CHILL DOWN TO BETWEEN 5 AND 10
DEGREES BELOW NORMAL OVER THE WEEKEND...AND THEN MODERATE TO A FEW
DEGREES ABOVE NORMAL IN RETURN FLOW BY TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
EXPECT GENERALLY IFR RESTRICTIONS TO CONTINUE WELL INTO THE
AFTERNOON AS SNOW ASSOCIATED WITH UPPER LEVEL SYSTEM MOVES ACROSS
THE TERMINALS. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE AFTERNOON
AS STEADY SNOW TAPERS OFF TO SNOW SHOWERS BEFORE COMING TO AN END
IN ALL LOCATIONS THIS EVENING. CLEARING IS EXPECTED BY MIDNIGHT
THAT WILL FURTHER IMPROVE FLIGHT CONDITIONS TO VFR.
OUTLOOK...THURSDAY THROUGH SUNDAY...
BUILDING HIGH PRESSURE IN THE WAKE OF THE LOW PRESSURE SYSTEM
WILL PROVIDE VFR FOR THE END OF THE WORK WEEK. ANOTHER COLD FRONT
IS FORECAST TO SPAWN MORE SHSN FRIDAY NIGHT INTO SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1047 AM EST WED FEB 8 2012
.SYNOPSIS...
AN UPPER LEVEL SYSTEM WILL BRING WIDESPREAD SNOW SHOWERS TO THE
AREA TODAY. HIGH PRESSURE WILL BRING SEASONABLE TEMPERATURES AND
DRY CONDITIONS ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UL WAVE IS SWINGING THROUGH THE UPPER OHIO VALLEY, AHEAD OF THE
MAIN TROUGH. THIS WAVE WILL MOVE THROUGH VERY QUICKLY...ENDING THE
SNOW FROM WEST TO EAST LATE THIS AFTERNOON.
CONFIDENT THAT THE HIGHEST AMOUNTS OF SNOW WILL BE 2 TO 4 INCHES
ACROSS THE RIDGE TOPS. ADVISORY CONTINUES FOR THE RIDGE COUNTIES
THROUGH THIS EVENING.
ELSEWHERE, A GENERAL 1 TO 2 WILL COVER MOST PLACES. ACCUMULATIONS
WILL BE LIMITED BY THE SPEED AT WHICH THIS SYSTEM WILL MOVE
THROUGH AND THAT MOST SFC TEMPS WILL RISE SLIGHTLY ABOVE FREEZING
TODAY, WITH THE EXCEPTION OF THE RIDGE TOPS.
TEMPERATURES ARE BLEND OF THE LATEST RUN OF THE HRRR AND 12Z NAM.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
SNOW SHOWERS ARE EXPECTED OVER THE SOUTHEAST RIDGES THIS EVENING,
WITH AN ADDITIONAL ACCUMULATION AROUND AN INCH POSSIBLE.
DRY HIGH PRESSURE WILL THEN BRING NEAR NORMAL TEMPERATURES INTO
FRIDAY.
FOR FRIDAY, MODELS CONTINUE TO HAVE TIMING ISSUES WITH ARCTIC
FRONT APPROACHING. HAVE GONE MIDDLE OF THE ROAD WITH HIGH CHANCE
TO LIKELY POPS LATE IN THE AFTERNOON. EXPECT A RAIN AND SNOW MIX
IN THE FAR SOUTH WITH SNOW ELSEWHERE. WILL PROBABLY AGAIN HAVE TO
DEAL WITH LIGHT ACCUMULATIONS. BUT WITH THIS SYSTEM, IT APPEARS
THE HIGHER ACCUMULATIONS WILL BE ACROSS THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LATEST ECMWF AND GFS MODEL RUNS CONTINUE TO SHOW A DEEP UPPER TROUGH
PLUNGING ACROSS EASTERN CANADA DURING THE WEEKEND. 00Z ECMWF
INDICATES A SURFACE WAVE DEVELOPING ALONG THE BOUNDARY WHICH WOULD
TEND TO SLOW DOWN EASTWARD PROGRESS FRIDAY NIGHT...AND WOULD
LENGTHEN DURATION OF PRECIPITATION INTO SATURDAY. REGARDLESS OF
TIMING...VERY COLD CYCLONIC FLOW BEHIND THE SYSTEM SHOULD MAINTAIN
SCATTERED SNOW SHOWERS OVER THE REGION THROUGH SATURDAY.
STRONG SURFACE HIGH IS PROGGED TO BUILD SOUTHEASTWARD INTO THE MS
VALLEY BY SUNDAY AND THEN SLIDE EAST TO THE ATLANTIC COAST BY
TUESDAY. TEMPERATURES ARE FORECAST TO CHILL DOWN TO BETWEEN 5 AND 10
DEGREES BELOW NORMAL OVER THE WEEKEND...AND THEN MODERATE TO A FEW
DEGREES ABOVE NORMAL IN RETURN FLOW BY TUESDAY.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
EXPECT GENERALLY IFR RESTRICTIONS TO CONTINUE WELL INTO THE
AFTERNOON AS SNOW ASSOCIATED WITH UPPER LEVEL SYSTEM MOVES ACROSS
THE TERMINALS. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE AFTERNOON
AS STEADY SNOW TAPERS OFF TO SNOW SHOWERS BEFORE COMING TO AN END
IN ALL LOCATIONS THIS EVENING. CLEARING IS EXPECTED BY MIDNIGHT
THAT WILL FURTHER IMPROVE FLIGHT CONDITIONS TO VFR.
OUTLOOK...THURSDAY THROUGH SUNDAY...
BUILDING HIGH PRESSURE IN THE WAKE OF THE LOW PRESSURE SYSTEM
WILL PROVIDE VFR FOR THE END OF THE WORK WEEK. ANOTHER COLD FRONT
IS FORECAST TO SPAWN MORE SHSN FRIDAY NIGHT INTO SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1022 AM EST WED FEB 8 2012
.SYNOPSIS...
AN UPPER LEVEL SYSTEM WILL BRING WIDESPREAD SNOW SHOWERS TO THE
AREA TODAY. HIGH PRESSURE WILL BRING SEASONABLE TEMPERATURES AND
DRY CONDITIONS ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UL WAVE IS SWINGING THROUGH THE UPPER OHIO VALLEY, AHEAD OF THE
MAIN TROUGH. THIS WAVE WILL MOVE THROUGH VERY QUICKLY...ENDING THE
SNOW FROM WEST TO EAST LATE THIS AFTERNOON.
CONFIDENT THAT THE HIGHEST AMOUNTS OF SNOW WILL BE 2 TO 4 INCHES
ACROSS THE RIDGE TOPS. ADVISORY CONTINUES FOR THE RIDGE COUNTIES
THROUGH THIS EVENING.
ELSEWHERE, A GENERAL 1 TO 2 WILL COVER MOST PLACES. ACCUMULATIONS
WILL BE LIMITED BY THE SPEED AT WHICH THIS SYSTEM WILL MOVE
THROUGH AND THAT MOST SFC TEMPS WILL RISE SLIGHTLY ABOVE FREEZING
TODAY, WITH THE EXCEPTION OF THE RIDGE TOPS.
TEMPERATURES ARE BLEND OF THE LATEST RUN OF THE HRRR AND 12Z NAM.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
SNOW SHOWERS ARE EXPECTED OVER THE SOUTHEAST RIDGES THIS EVENING,
WITH AN ADDITIONAL ACCUMULATION AROUND AN INCH POSSIBLE.
DRY HIGH PRESSURE WILL THEN BRING NEAR NORMAL TEMPERATURES INTO
FRIDAY.
FOR FRIDAY, MODELS CONTINUE TO HAVE TIMING ISSUES WITH ARCTIC
FRONT APPROACHING. HAVE GONE MIDDLE OF THE ROAD WITH HIGH CHANCE
TO LIKELY POPS LATE IN THE AFTERNOON. EXPECT A RAIN AND SNOW MIX
IN THE FAR SOUTH WITH SNOW ELSEWHERE. WILL PROBABLY AGAIN HAVE TO
DEAL WITH LIGHT ACCUMULATIONS. BUT WITH THIS SYSTEM, IT APPEARS
THE HIGHER ACCUMULATIONS WILL BE ACROSS THE NORTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LATEST ECMWF AND GFS MODEL RUNS CONTINUE TO SHOW A DEEP UPPER TROUGH
PLUNGING ACROSS EASTERN CANADA DURING THE WEEKEND. 00Z ECMWF
INDICATES A SURFACE WAVE DEVELOPING ALONG THE BOUNDARY WHICH WOULD
TEND TO SLOW DOWN EASTWARD PROGRESS FRIDAY NIGHT...AND WOULD
LENGTHEN DURATION OF PRECIPITATION INTO SATURDAY. REGARDLESS OF
TIMING...VERY COLD CYCLONIC FLOW BEHIND THE SYSTEM SHOULD MAINTAIN
SCATTERED SNOW SHOWERS OVER THE REGION THROUGH SATURDAY.
STRONG SURFACE HIGH IS PROGGED TO BUILD SOUTHEASTWARD INTO THE MS
VALLEY BY SUNDAY AND THEN SLIDE EAST TO THE ATLANTIC COAST BY
TUESDAY. TEMPERATURES ARE FORECAST TO CHILL DOWN TO BETWEEN 5 AND 10
DEGREES BELOW NORMAL OVER THE WEEKEND...AND THEN MODERATE TO A FEW
DEGREES ABOVE NORMAL IN RETURN FLOW BY TUESDAY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
CIGS WILL DROP AROUND SUNRISE TO MVFR AT MOST LOCATIONS IN
ADVANCE OF WEAK LOW PRESSURE SYSTEM. EXPECT THAT ALL LOCATIONS
EXCEPT FKL AND DUJ WILL DROP TO IFR AS WIDESPREAD SNOW MOVES IN
FROM SOUTHWEST TO NORTHEAST. FKL AND DUJ ARE EXPECTED TO REMAIN
MVFR THROUGH THE EVENT AS SNOW SHOULD BE LIGHTER COMPARED TO
LOCATIONS FARTHER TO THE SOUTH. THINK THAT SNOW COULD TAPER OFF
TO SNOW SHOWERS AROUND SUNSET BEFORE COMING TO AN END IN ALL
LOCATIONS THIS EVENING. CLEARING IS EXPECTED BY MIDNIGHT THAT WILL
BRING FLIGHT CONDITIONS BACK TO VFR.
OUTLOOK...THURSDAY THROUGH SATURDAY...
BUILDING HIGH PRES IN THE WAKE OF THE LOW PRESSURE SYSTEM WILL
PROVIDE VFR FOR THE END OF THE WORK WEEK...BUT ANOTHER COLD FRONT
IS FORECAST TO SPAWN MORE SHSN FRIDAY NIGHT INTO SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
548 PM CST THU FEB 9 2012
.UPDATE...
.AVIATION.../00Z TAF ISSUANCE/
ARCTIC COLD FRONT PUSHING SOUTH THIS EVENING AND WILL MOVE
THROUGH ALL TAF SITES BY 06Z. BAND OF MVFR CIGS AND LOW END VFR
CIGS ASSOCIATED WITH THE FRONT. MVFR CIGS COULD BE AS LOW AS
015. IT APPEARS THAT THE MVFR CIGS MAY ONLY LAST 4 TO 5 HOURS AND
ANY ONE LOCATION BUT THEN LOW END VFR BKN CIGS COULD PERSIST
OVERNIGHT IN THE COLD ADVECTION. THERE IS A BAND OF LIGHT SNOW AS
WELL...WHICH IS OVER NORTHEAST MN PRIOR TO 00Z. THE FORCING
ASSOCIATED WITH THIS COULD MOVE INTO PARTS OF WEST CENTRAL
WISCONSIN AFTER 03Z. THE GREATEST RISK OF MVFR VSBYS WILL BE AT
KEAU. WILL NEED TO WATCH TRENDS ON THIS AS IT COULD AFFECT KRNH
AND POSSIBLY BRIEF IFR VSBYS AT KEAU. THE COLD AIR WILL CONTINUE
TO MOVE INTO THE AREA ON FRIDAY WITH A MAINLY SCT DECK OF CLOUDS
025-035 BUT THERE STILL MAY LINGERING CEILINGS KRNH AND KEAU IN THE
MORNING.
KMSP...COLD FRONT APPROACHING THE FIELD 03Z-04Z WITH MVFR CIGS
GENERALLY ABOVE 017. THERE WILL LIKELY BE FLURRIES OR A SNOW
SHOWER BUT CURRENTLY NOT CALLING FOR VSBY RESTRICTIONS. WILL
STILL NEED TO WATCH TRENDS THOUGH IF LIGHT SNOW COVERAGE EXPANDS
OVER WEST CENTRAL WISCONSIN. EXPECT THE VFR CIGS TO BREAK UP
AROUND 11Z WITH SCT CONDITIONS DURING THE DAY. LIKELY SKC
CONDITIONS BY 21Z. NORTHWEST WINDS AFTER 03Z WITH SUSTAINED SPEEDS
15-17 KNOTS WITH GUSTS TO 25 KNOTS. WINDS SETTLING DOWN AFTER
18Z.
&&
.DISCUSSION...
ARCTIC COLD FRONT WITH DECENT PRESSURE FALLS OVER NORTH DAKOTA DROPPING
SOUTH ABOUT AS FORECAST. NOT TOO MANY SITES REPORTING SNOW BUT
A COUPLE OF SITES IN NW ONT WERE DOWN TO AROUND 2SM. THE LATEST RUC
AND THE NAM TO A LESSER EXTENT DO FORECAST AN INCREASE IN QG VERT
VEL AND FGEN TO OUR NE AS THE FRONT DROPS SOUTH WILL INCREASE POPS
TO A CHANCE CATEGORY OVER IN WEST CENTRAL WI TO ACCOUNT FOR THIS.
WITH THE FRONT MOVING DOWN WILL GO WITH A MODEL WEIGHTED DIURNAL
TEMP TREND OVERNIGHT. SOME GUSTY WINDS FOR A TIME WITH THE COLD
ADVECTION TOO. NOT MUCH TEMP CHANGE FROM THE MORNING IN THE SE
FOR FRIDAY HIGHS.
FEEL THAT THE NAM IS OVERDOING THE LOW LEVEL MOISTURE FIELDS ON
FRIDAY WITH THE GFS AND RUC LOOKING BETTER AT LEAST IN THE MN
PORTION OF THE AREA. COLD ADVECTION OS THERE...BUT WE LOOSE THE
CYCLONIC CURVATURE IN THE AFTERNOON. LOOKS LIKE A COLD LOOKS
COLD FRIDAY NIGHT UNDER CLEAR SKIES BUT WITH A PRES GRADIENT
CONTINUING. MOST SITES LIKELY BELOW ZERO BUT THIS REGIME IS NOT
AS COLD AS THE MID JANUARY BLAST.
MODERATION BEGINS LATE IN THE WEEKEND AND EARLY NEXT WEEK WITH A
RETURN TO A MORE WESTERLY FLOW BUT SOMEWHAT SPLIT WITH MORE
BLOCKING AROUND THE NORTHERN HEMISPHERE. WE STILL HAVE A CHANCE OF
SNOW FOR SOUTHERN AREAS MONDAY AND MONDAY NIGHT WITH A CENTRAL
PLAINS TROUGH. PRECIP PROBS BETTER IN THE CENTRAL PLAINS THOUGH.
THERE HAD BEEN SOME CHANCE AGAIN LATER WEDNESDAY AND THURSDAY BUT
THE 12Z ECMWF...AND GFS ENSEMBLE POPS ARE NOT SHOWING MUCH. THE
12Z GFS IS THE ONLY MODEL TO SHOW SOME A CHANCE BUT THIS A LITTLE
CLOSE BEHIND THE MONDAY SYSTEM IN A SPLIT FLOW. TEMPS BACK TO NEAR
OR ABOVE NORMAL NEXT WEEK.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/JPR
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1005 AM MST WED FEB 8 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
LOW CLOUDS CONTINUE TO ERODE THIS MORNING...LINGERING IN THE
NORTHEAST AND WESTERN MOST ZONES. UPDATING FORECAST FOR CONTINUED
DIMINISHING CLOUD COVER TODAY. ALSO LOWERED TEMPERATURES SLIGHTLY
FOR THE NORTHEAST WITH CLOUDS EXPECTED TO LINGER LONGEST. EBERT
PREVIOUS SHORT TERM DISCUSSION...THE SHORT TERM OF THE FORECAST
STARTS OUT DIFFICULT WITH A SURFACE HIGH EXTENDING INTO EXTREME
NORTHEAST MONTANA...AND AN UPPER LOW OVERHEAD. A MASS OF STRATUS
CLOUDS RESIDES OVER MOST OF NORTHEAST MONTANA AND SOUTHERN
SASKATCHEWAN THIS MORNING. HRRR MODEL MOVES THE MASS MORE NORTH
INTO SASKATCHEWAN...HOWEVER DOES HOLD SOME BACK OVER THE
NORTHEASTERN ZONES THROUGH THE DAY. GOING TO TREND TOWARDS AGAIN
SOME CLEARING AS PER THE HRRR MODEL... BUT CONFIDENCE ISN/T 100
PERCENT THAT THE STRATUS WON/T LIFT OUT UNTIL THE LOW LEVEL
EASTERLY FLOW SHIFTS WEST THIS EVENING.
TONIGHT... FOR NOW WILL GO WITH THE PARTLY CLOUDY SKY COVER...
HOWEVER LOOKING AT LAYERED RH HAS SOME CONCERN THAT THE MASS OF
STRATUS OVER SASKATCHEWAN WILL PUSH SOUTH AGAIN. KEEPING THAT IN
MIND DID A SPLIT ON TEMPERATURES...IF THE AREA STAYS CLEAR THE
FORECAST WILL BUST TOO WARM. IF THE STRATUS DOES COME IN THEN THE
FORECAST WILL SIDE TOO COLD.
THURSDAY...COLD AIR SPILLS IN FROM CENTRAL CANADA AND FORMS A
BOUNDARY WITH THE PACIFIC AIR MASS OVER CENTRAL MONTANA. THIS
SHOULD KEEP ANY SNOW FALL OUTSIDE OF THE FORECAST AREA WITH THE
EXCEPTION OF THE FAR SOUTHWESTERN ZONES. SKY COVER WILL BE HARD TO
HANDLE DURING THIS PERIOD. STRONG SURFACE HIGH AND DRY AIR WILL
KEEP THE NORTHEASTERN ZONES CLEAR...BUT AS THE PACIFIC MODIFIED
AIR MASS CLIMBS THE DEEP ARCTIC AIR A DECK OF CLOUDS IN VICINITY
OF THE FRONT.
THIS TREND WILL CONTINUE THURSDAY NIGHT INTO FRIDAY WITH
RE-ENFORCING SHOTS OF COLD AIR OVER THE EASTERN ZONES FROM THE
UPPER LOW OVER HUDSON BAY. PROTON
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE PERIOD STARTS OUT ON THE COLD SIDE WITH A CANADIAN HIGH
PRESSURE STILL INFLUENCING THE AREA FRI NIGHT/SAT. THE AMPLIFIED
PATTERN BREAKS DOWN...WITH THE WESTERN RIDGE WEAKENING AND MOVING
E. THIS ALLOWS SHORTWAVES TO START MOVING INLAND ACROSS THE WESTERN
STATES BEGINNING SUNDAY.
QUITE A FEW MODEL DIFFERENCES WITH THESE SHORTAVES...TIMING...INTENSITY...
AND DIRECTION OF MOVEMENT. 00Z GFS QUITE DIFFERENT WITH A WEAKER
TUE SYSTEM...ENERGY ABSORBED BY A QUICKLY FOLLOWING WED SYSTEM.
THERE IS SIGNIFICANT WEAKENING OF THE UPPER FLOW OVER THE WESTERN
STATES...MAKING SPLITTING OF ENERGY LIKELY WITH THESE SYSTEMS. NONE OF
THESE SHORTWAVES ARE VERY STRONG EITHER. JUST ENOUGH MODEL
CONSENSUS TO EXPECT THE FIRST SHORTWAVE SUNDAY TO BE WEAKER THAN
THE 2ND SYSTEM TUE/TUE NIGHT. WILL MAINTAIN JUST A LITTLE HIGHER
POP FOR THESE. EXPECT PRECIP TYPE AS MAINLY LIGHT SNOW...ALTHOUGH
HIGHS LIKELY TO BE A LITTLE ABOVE FREEZING TUE. SIMONSEN
&&
.AVIATION...
LIMITED CLEARING SKIES...BRINGING VFR CONDITIONS...HAVE FINALLY
RETURNED TO ALL TAF SITES IN NORTHEAST MONTANA WITH LINGERING IFR
CONDITIONS ONLY VERY RECENTLY CLEARING AWAY TOWARD THE NORTHEAST
FROM KSDY. GUSTIER NORTHWEST WINDS WILL SET UP ON THURSDAY AS MVFR
CONDITIONS IN THE FORM OF SOME LOW LEVEL CLOUDS MAY SNEAK IN
TOWARD THE END OF THIS TAF CYCLE. BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
350 AM MST WED FEB 8 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
THE SHORT TERM OF THE FORECAST STARTS OUT DIFFICULT WITH A SURFACE
HIGH EXTENDING INTO EXTREME NORTHEAST MONTANA...AND AN UPPER LOW
OVERHEAD. A MASS OF STRATUS CLOUDS RESIDES OVER MOST OF NORTHEAST
MONTANA AND SOUTHERN SASKATCHEWAN THIS MORNING. HRRR MODEL MOVES
THE MASS MORE NORTH INTO SASKATCHEWAN...HOWEVER DOES HOLD SOME
BACK OVER THE NORTHEASTERN ZONES THROUGH THE DAY. GOING TO TREND
TOWARDS AGAIN SOME CLEARING AS PER THE HRRR MODEL... BUT
CONFIDENCE ISN/T 100 PERCENT THAT THE STRATUS WON/T LIFT OUT UNTIL
THE LOW LEVEL EASTERLY FLOW SHIFTS WEST THIS EVENING.
TONIGHT... FOR NOW WILL GO WITH THE PARTLY CLOUDY SKY COVER...
HOWEVER LOOKING AT LAYERED RH HAS SOME CONCERN THAT THE MASS OF
STRATUS OVER SASKATCHEWAN WILL PUSH SOUTH AGAIN. KEEPING THAT IN
MIND DID A SPLIT ON TEMPERATURES...IF THE AREA STAYS CLEAR THE
FORECAST WILL BUST TOO WARM. IF THE STRATUS DOES COME IN THEN THE
FORECAST WILL SIDE TOO COLD.
THURSDAY...COLD AIR SPILLS IN FROM CENTRAL CANADA AND FORMS A
BOUNDARY WITH THE PACIFIC AIR MASS OVER CENTRAL MONTANA. THIS
SHOULD KEEP ANY SNOW FALL OUTSIDE OF THE FORECAST AREA WITH THE
EXCEPTION OF THE FAR SOUTHWESTERN ZONES. SKY COVER WILL BE HARD TO
HANDLE DURING THIS PERIOD. STRONG SURFACE HIGH AND DRY AIR WILL
KEEP THE NORTHEASTERN ZONES CLEAR...BUT AS THE PACIFIC MODIFIED
AIR MASS CLIMBS THE DEEP ARCTIC AIR A DECK OF CLOUDS IN VICINITY
OF THE FRONT.
THIS TREND WILL CONTINUE THURSDAY NIGHT INTO FRIDAY WITH
RE-ENFORCING SHOTS OF COLD AIR OVER THE EASTERN ZONES FROM THE
UPPER LOW OVER HUDSON BAY. PROTON
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE PERIOD STARTS OUT ON THE COLD SIDE WITH A CANADIAN HIGH
PRESSURE STILL INFLUENCING THE AREA FRI NIGHT/SAT. THE AMPLIFIED
PATTERN BREAKS DOWN...WITH THE WESTERN RIDGE WEAKENING AND MOVING
E. THIS ALLOWS SHORTWAVES TO START MOVING INLAND ACROSS THE WESTERN
STATES BEGINNING SUNDAY.
QUITE A FEW MODEL DIFFERENCES WITH THESE SHORTAVES...TIMING...INTENSITY...
AND DIRECTION OF MOVEMENT. 00Z GFS QUITE DIFFERENT WITH A WEAKER
TUE SYSTEM...ENERGY ABSORBED BY A QUICKLY FOLLOWING WED SYSTEM.
THERE IS SIGNIFICANT WEAKENING OF THE UPPER FLOW OVER THE WESTERN
STATES...MAKING SPLITTING OF ENERGY LIKELY WITH THESE SYSTEMS. NONE OF
THESE SHORTWAVES ARE VERY STRONG EITHER. JUST ENOUGH MODEL
CONSENSUS TO EXPECT THE FIRST SHORTWAVE SUNDAY TO BE WEAKER THAN
THE 2ND SYSTEM TUE/TUE NIGHT. WILL MAINTAIN JUST A LITTLE HIGHER
POP FOR THESE. EXPECT PRECIP TYPE AS MAINLY LIGHT SNOW...ALTHOUGH
HIGHS LIKELY TO BE A LITTLE ABOVE FREEZING TUE. SIMONSEN
&&
.AVIATION...
PERSISTENT OVERCAST MVFR CEILINGS AT 2K FT AGL ARE ALREADY SHOWING
DEFINITE SIGNS OF BREAKING UP EARLY THIS MORNING. IT IS EXPECTED
THAT OUR 4 TAF SITES IN NE MT...OLF...GGW...SDY...GDV WILL BECOME
SCATTERED BY 12-14Z...THEN CLEAR. ALL REMAINING AREAS OF NE MT
SHOULD BE VFR BY 16Z. SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1247 PM CST WED FEB 8 2012
.AVIATION...
18Z TAFS FOR KOFK...KLNK AND KOMA.
STLT IMAGERY AND OBS SHOW AN AREA OF MVFR CIGS WEST OF KOFK AND
OVER KLNK...KOMA. THE CIGS WILL BE VARIABLE AS A LOOP SHOW SOME
DISSIPATING CLOUDS TRYING TO MOVE TOWARD KLNK FM THE
NORTH...ALTHOUGH CLDS HAD SCATTERED OUT A KOMA...HAVE REDEVELOPED.
RH PROGS DO NOT HAVE A HANDLE ON THESE AS SOME ARE DRIER IN THE
LOW LEVELS AND OTHERS SATURATED. OVERALL WILL CONTINUE TO MENTION
MVFR OR VARIABLE MVFR CIGS THIS AFTERNOON...BECOMING PREDOMINANT
AT ALL THREE SITES AND CONTINUING OVERNIGHT. SOME MVFR VSBYS ARE
EXPECTED AS WELL. WEST OR SOUTHWEST WINDS ARE 5 TO 10KTS AT
KOFK...AND LIGHT AND VARIABLE AT KOMA AND KLNK. WINDS SHOULD BE
LIGHT...THEN INCREASE OUT OF THE SOUTHWEST THURSDAY MORNING. WITH
THE INCREASING WINDS EXPECT THE LOW CLOUDS TO IMPROVE FROM MID
MORNING ON.
&&
.PREV DISCUSSION... /ISSUED 508 AM CST WED FEB 8 2012/
AVIATION...
12Z TAFS FOR KOFK...KLNK AND KOMA.
MVFR CIGS NEAR FL025 WILL CLEAR THE KOFK AREA EARLY...HOWEVER CIGS
BETWEEN FL025 AND FL035 WILL REMAIN OVER KLNK AND KOMA THROUGH THE
DAY. AS WINDS TURN TO THE SOUTHWEST LATE IN THE DAY...MVFR CIGS
BELOW FL020 SHOULD RETURN TO ALL TAF SITES...GENERALLY AROUND 00Z.
A GRADUAL LOWERING OF CIGS TO BELOW FL010 IS EXPECTED BY 06Z WITH
AREAS OF 5SM FOG.
DERGAN
PREV DISCUSSION... /ISSUED 316 AM CST WED FEB 8 2012/
DISCUSSION...
SFC HIGH PRESSURE CONTINUES TO MOVE SOUTH OVER THE FORECAST AREA
THIS MORNING WHILE LOW CLOUDS LINGER OVERHEAD. DIFFICULT TO GET A
GOOD HANDLE ON HOW QUICKLY/SLOWLY THE STRATUS DECK WILL ERODE. SOME
CLEARING HAS TAKEN PLACE OVER THE NORTHERN CWA AND ACROSS THE
MISSOURI RIVER VALLEY...HOWEVER THIS HAS BEEN A GENERALLY SLOW
PROCESS THIS MORNING. LATEST RUC AND HRRR MODEL RUNS SHOW SLOW SOUTHWARD
CLEARING SO WL KEEP MOSTLY CLOUDY GOING IN THE SOUTH WITH PARTLY
CLOUDY IN OUR NORTH FOR THE FIRST HALF OF THE DAY. IN THE UPPER
LEVELS...A PIECE OF ENERGY OVER EASTERN MONTANA WILL CONTINUE TO
MOVE SOUTHEAST TOWARD THE FORECAST AREA BY TONIGHT. FORCING
REMAINS VERY WEAK AND MOISTURE IS LIMITED SO NO MENTION OF
FLURRIES OR LIGHT SNOW WITH THE PASSAGE OF THIS WAVE.
WEAK WARM AIR ADVECTION SETS UP ON THURSDAY IN RETURN FLOW
REGIME...PROVIDING A BRIEF WARM UP INTO THE LOWER TO MID 30S. A
STRONG PUSH OF COLD AIR WILL SPREAD SOUTH ACROSS THE NRN PLAINS AND
INTO THE MIDWEST BY THURSDAY NIGHT IN ASSOCIATION WILL UPPER
TROF DIGGING ACROSS EASTERN CANADA. THE COLDER TEMPS WL CONTINUE
THROUGH THE WEEKEND WITH THE COLDEST OF THE DAYS ON SATURDAY. HIGHS
OVER THE SNOW COVER WILL LIKELY STRUGGLE TO WARM ABOVE THE UPPER
TEENS.
SFC HIGH PRESSURE BUILDS OVER THE CWA ONCE AGAIN ON SUNDAY WITH
STRONG WARM AIR ADVECTION RETURNING SUNDAY NIGHT. MEDIUM RANGE
MODELS IN GOOD AGREEMENT ON MOVING A SHORTWAVE TROF THRU THE FOUR
CORNERS REGION SUNDAY NIGHT AND INTO THE CENTRAL PLAINS BY MONDAY
MORNING. FORCING AHEAD OF THIS WAVE SHOULD ALLOW SNOW TO DEVELOP
SUNDAY NIGHT INTO MONDAY ACROSS MUCH OF THE SOUTHERN FORECAST
AREA.
YET ANOTHER WAVE IS PROGGED TO MOVE INTO THE CNTRL PLAINS FOR MID
WEEK. MODELS KEEP GETTING A BIT STRONGER WITH THIS SYSTEM AND
CONTINUE TO CLOSE IT OFF AS IT MOVES INTO THE CNTRL PLAINS.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
508 AM CST WED FEB 8 2012
.AVIATION...
12Z TAFS FOR KOFK...KLNK AND KOMA.
MVFR CIGS NEAR FL025 WILL CLEAR THE KOFK AREA EARLY...HOWEVER CIGS
BETWEEN FL025 AND FL035 WILL REMAIN OVER KLNK AND KOMA THROUGH THE
DAY. AS WINDS TURN TO THE SOUTHWEST LATE IN THE DAY...MVFR CIGS
BELOW FL020 SHOULD RETURN TO ALL TAF SITES...GENERALLY AROUND 00Z.
A GRADUAL LOWERING OF CIGS TO BELOW FL010 IS EXPECTED BY 06Z WITH
AREAS OF 5SM FOG.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 316 AM CST WED FEB 8 2012/
DISCUSSION...
SFC HIGH PRESSURE CONTINUES TO MOVE SOUTH OVER THE FORECAST AREA
THIS MORNING WHILE LOW CLOUDS LINGER OVERHEAD. DIFFICULT TO GET A
GOOD HANDLE ON HOW QUICKLY/SLOWLY THE STRATUS DECK WILL ERODE. SOME
CLEARING HAS TAKEN PLACE OVER THE NORTHERN CWA AND ACROSS THE
MISSOURI RIVER VALLEY...HOWEVER THIS HAS BEEN A GENERALLY SLOW
PROCESS THIS MORNING. LATEST RUC AND HRRR MODEL RUNS SHOW SLOW SOUTHWARD
CLEARING SO WL KEEP MOSTLY CLOUDY GOING IN THE SOUTH WITH PARTLY
CLOUDY IN OUR NORTH FOR THE FIRST HALF OF THE DAY. IN THE UPPER
LEVELS...A PIECE OF ENERGY OVER EASTERN MONTANA WILL CONTINUE TO
MOVE SOUTHEAST TOWARD THE FORECAST AREA BY TONIGHT. FORCING
REMAINS VERY WEAK AND MOISTURE IS LIMITED SO NO MENTION OF
FLURRIES OR LIGHT SNOW WITH THE PASSAGE OF THIS WAVE.
WEAK WARM AIR ADVECTION SETS UP ON THURSDAY IN RETURN FLOW
REGIME...PROVIDING A BRIEF WARM UP INTO THE LOWER TO MID 30S. A
STRONG PUSH OF COLD AIR WILL SPREAD SOUTH ACROSS THE NRN PLAINS AND
INTO THE MIDWEST BY THURSDAY NIGHT IN ASSOCIATION WILL UPPER
TROF DIGGING ACROSS EASTERN CANADA. THE COLDER TEMPS WL CONTINUE
THROUGH THE WEEKEND WITH THE COLDEST OF THE DAYS ON SATURDAY. HIGHS
OVER THE SNOW COVER WILL LIKELY STRUGGLE TO WARM ABOVE THE UPPER
TEENS.
SFC HIGH PRESSURE BUILDS OVER THE CWA ONCE AGAIN ON SUNDAY WITH
STRONG WARM AIR ADVECTION RETURNING SUNDAY NIGHT. MEDIUM RANGE
MODELS IN GOOD AGREEMENT ON MOVING A SHORTWAVE TROF THRU THE FOUR
CORNERS REGION SUNDAY NIGHT AND INTO THE CENTRAL PLAINS BY MONDAY
MORNING. FORCING AHEAD OF THIS WAVE SHOULD ALLOW SNOW TO DEVELOP
SUNDAY NIGHT INTO MONDAY ACROSS MUCH OF THE SOUTHERN FORECAST
AREA.
YET ANOTHER WAVE IS PROGGED TO MOVE INTO THE CNTRL PLAINS FOR MID
WEEK. MODELS KEEP GETTING A BIT STRONGER WITH THIS SYSTEM AND
CONTINUE TO CLOSE IT OFF AS IT MOVES INTO THE CNTRL PLAINS.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
316 AM CST WED FEB 8 2012
.DISCUSSION...
SFC HIGH PRESSURE CONTINUES TO MOVE SOUTH OVER THE FORECAST AREA
THIS MORNING WHILE LOW CLOUDS LINGER OVERHEAD. DIFFICULT TO GET A
GOOD HANDLE ON HOW QUICKLY/SLOWLY THE STRATUS DECK WILL ERODE. SOME
CLEARING HAS TAKEN PLACE OVER THE NORTHERN CWA AND ACROSS THE
MISSOURI RIVER VALLEY...HOWEVER THIS HAS BEEN A GENERALLY SLOW
PROCESS THIS MORNING. LATEST RUC AND HRRR MODEL RUNS SHOW SLOW SOUTHWARD
CLEARING SO WL KEEP MOSTLY CLOUDY GOING IN THE SOUTH WITH PARTLY
CLOUDY IN OUR NORTH FOR THE FIRST HALF OF THE DAY. IN THE UPPER
LEVELS...A PIECE OF ENERGY OVER EASTERN MONTANA WILL CONTINUE TO
MOVE SOUTHEAST TOWARD THE FORECAST AREA BY TONIGHT. FORCING
REMAINS VERY WEAK AND MOISTURE IS LIMITED SO NO MENTION OF
FLURRIES OR LIGHT SNOW WITH THE PASSAGE OF THIS WAVE.
WEAK WARM AIR ADVECTION SETS UP ON THURSDAY IN RETURN FLOW
REGIME...PROVIDING A BRIEF WARM UP INTO THE LOWER TO MID 30S. A
STRONG PUSH OF COLD AIR WILL SPREAD SOUTH ACROSS THE NRN PLAINS AND
INTO THE MIDWEST BY THURSDAY NIGHT IN ASSOCIATION WILL UPPER
TROF DIGGING ACROSS EASTERN CANADA. THE COLDER TEMPS WL CONTINUE
THROUGH THE WEEKEND WITH THE COLDEST OF THE DAYS ON SATURDAY. HIGHS
OVER THE SNOW COVER WILL LIKELY STRUGGLE TO WARM ABOVE THE UPPER
TEENS.
SFC HIGH PRESSURE BUILDS OVER THE CWA ONCE AGAIN ON SUNDAY WITH
STRONG WARM AIR ADVECTION RETURNING SUNDAY NIGHT. MEDIUM RANGE
MODELS IN GOOD AGREEMENT ON MOVING A SHORTWAVE TROF THRU THE FOUR
CORNERS REGION SUNDAY NIGHT AND INTO THE CENTRAL PLAINS BY MONDAY
MORNING. FORCING AHEAD OF THIS WAVE SHOULD ALLOW SNOW TO DEVELOP
SUNDAY NIGHT INTO MONDAY ACROSS MUCH OF THE SOUTHERN FORECAST
AREA.
YET ANOTHER WAVE IS PROGGED TO MOVE INTO THE CNTRL PLAINS FOR MID
WEEK. MODELS KEEP GETTING A BIT STRONGER WITH THIS SYSTEM AND
CONTINUE TO CLOSE IT OFF AS IT MOVES INTO THE CNTRL PLAINS.
KERN
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
BAND OF LIGHT SNOW SHIFTED SOUTH OF KOMA EARLIER THIS EVENING AND
SHOULD STAY MOSTLY SOUTHEAST OF KLNK. LOW CLOUDS CONTINUED TO
SLOWLY DECREASE IN THE FAR NORTHERN PARTS OF NORTHEAST NEBRASKA
AS OF 05Z...BUT REMAINED IN PLACE FOR MOST OF THE AREA.
CONFIDENCE IN TAF FORECASTS REMAINS LOW...DUE TO UNCERTAINTY WITH
LOW LEVEL MOISTURE SHOWN BY THE 00Z MODELS AND THE AFFECTS OF
CURRENT SNOW COVER. GENERALLY TRIED TO FOLLOW NAM 925 MB RH PROGS
TO TIME CEILINGS. LOW CLOUDS ARE EXPECTED TO DECREASE LATER
TONIGHT OR EARLY WEDNESDAY MORNING AT KOFK AND KOMA...BUT MAY NOT
MOVE OUT AROUND KLNK. RIDGE OF HIGH PRESSURE AT THE SURFACE FROM
THE EASTERN DAKOTAS INTO THE TEXAS PANHANDLE WILL CONTINUE TO
BUILD SOUTHWARD AND LOW LEVEL WINDS SHOULD BECOME WEST OR
SOUTHWEST BY WEDNESDAY AFTERNOON. THIS MAY ALLOW CLOUDS TO MOVE
BACK IN FOR KOFK AND KOMA WEDNESDAY AFTERNOON OR EVENING.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
929 PM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE MAINLY CLEAR SKIES THROUGH FRIDAY
MORNING. A COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT,
BRINGING SOME SNOW SHOWERS AND MUCH COLDER AIR FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
925 PM UPDATE...SKC ACRS THE RGN ATTM. HRRR/RUC ARE INDICATING
POTNL FOR SOME STRATUS BY DAYBREAK INTO STEUBEN COUNTY...AND THIS
COULD WORK EWD INTO THE ELM AREA. AFTER SUNRISE...EXPECT ANY LOW
CLDS TO BREAK UP. OTRW JUST SOME MINOR 1ST TWEEKS FOR THE EVNG
UPDATE. PREV BLO...
HIGH PRES OVER THE OHIO VALLEY WILL PROVIDE CLEAR SKIES OVERNIGHT
ALONG WITH SEASONAL TEMPS. A SOUTHWEST GRADIENT WILL PREVENT TEMPS
FROM FREE FALLING BUT MINS WILL STILL RANGE FROM THE TEENS TO
LOWER 20S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
FRIDAY...A COLD FRONT WILL START DROPPING THROUGH THE UPPER GREAT
LAKES AS SFC HIGH PRES MOVES TO THE MID ATLANTIC REGION. MODELS
HAVE SLOWED PROGRESS OF THIS FRONT SO THE PERIOD WILL BE DRY WITH
JUST INCREASING MID/HIGH LEVEL MOISTURE DURING THE AFTERNOON. MAX
TEMPS WILL RANGE FROM THE MID 30S TO AROUND 40.
FRIDAY NIGHT...MODELS INDICATE SFC LOW DEVELOPING IN THE MID
ATLANTIC REGION WILL SLOW PROGRESS OF ARCTIC FRONT. FRONT WILL
CROSS AREA BETWEEN 06Z-12Z. INCREASED POPS ACROSS THE NRN CWA DUE
TO COLD FRONT AND SRN CWA DUE TO SOUTHERN SYSTEM. AFTER MIDNIGHT
HAVE LIKELY POPS NORTH AND SOUTH AND JUST HIGH CHC OVER THE
CENTRAL FA. TOTAL SNOW ACCUMS AROUND AN INCH NORTH/SOUTH AND LESS
THAN AN INCH ACROSS THE CENTRAL FA.
SATURDAY...BEHIND COLD FRONT LOW LEVEL FLOW WILL BE FROM THE
NORTHWEST BUT WITH PLENTY OF SHEAR AND SOME SFC RIDGING NOT MUCH
LAKE RESPONSE EXPECTED. WILL CONTINUE WITH CHC POPS DURING THE
MORNING WITH HIGHEST POPS THROUGH THE FINGER LAKES REGION AND
CENTRAL SOUTHERN TIER. DUE TO LOW LEVEL DRYING LOWERED POPS DURING
THE AFTERNOON. STRONG CAA WILL OCCUR THROUGHOUT THE DAY WITH TEMPS
FALLING DURING THE DAY.
SATURDAY NIGHT...SECONDARY TROF SWINGS THROUGH THE REGION LATE
NIGHT. CONDITIONS BECOME MORE FAVORABLE FOR LES AFTER MIDNIGHT
UNDER 300 FLOW. MODELS INDICATE BETTER LOW LEVEL INSTABILITY,
SYNOPTIC MOISTURE AND POSSIBLE MULTI LAKE CONNECTION. WILL RAISE
POPS TO LIKELY ACROSS NRN CWA AFTER MIDNIGHT WITH SEVERAL INCHES
OF ACCUM POSSIBLE AND JUST CHC/SLIGHT CHC ELSEWHERE. LOWS WILL
RANGE FROM THE SINGLE NUMBERS TO TEENS.
SUNDAY...BEHIND SECONDARY TROF NORTHWEST FLOW ONCE AGAIN PERSISTS
WITH POSSIBLE WELL ORGANIZED SNOW BAND LIKELY TO DROP SOUTH AND
DIMINISH. WILL HAVE CHC POPS ACROSS CENTRAL NEW YORK WITH HIGHER
POPS DURING THE MORNING HOURS. MAX TEMPS WILL GENERALLY RANGE FROM
THE LOWER TO MID 20S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
LONG TERM PD BEGINS WITH THE END OF THE CAA PTRN OF THE
WEEKEND...AND A FEW LE SNOW SHWRS OVER THE NY ZONES. TROF QUICKLY
LIFTS EAST ON MON AND ALLOWS MUCH MILDER AIR TO RETURN TO THE AREA
UNDER MAINLY CLR SKIES. BALANCE OF THE LONG TERM WILL HAVE NEAR
NRML TEMPS AND SPOTTY LGT PCPN. WEAK WV RETURNS PCPN TO THE AREA
TUE WITH ENUF MILD AIR TO BRING SOME MIXED PCPN. COLDER AIR
RETURNING BHD THE WV WITH RESULT IN SOME LGT SNOW SHWRS TUE NGT
INTO WED.
MODELS IN GOOD GNRL AGREEMENT SO TEMP AND PCPN HAS RELATIVELY HIGH
CONFIDENCE. FOR TEMPS...FLWD HPC GUID WHICH WAS IN GOOD AGREEMENT
WITH THE MEX.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
SKC/VFR CRNTLY ACRS THE FCST AREA AND CONDITIONS XPCTD TO REMAIN
UNCHANGED FOR MOST OF THE OVRNGT HRS. HOWEVER...AREA OF STRATUS
OVER OH IS CREEPING NEWD. SIG DIFFS IN THE MDLS W/RESPECT TO THESE
CLDS. RUC APPEARS TO HAVE THE BEST HANDLE ON THIS LOW LVL
MSTR...BUT ALSO STANDS OUT AS THE MDL WHICH CLEARLY BRINGS IN
THIS LOW CLD INTO WRN SXNS BY MRNG. CORRESPONDINGLY...HRRR CIG
DATA SHOWS MVFR INTO STEUBEN COUNTY 09-10Z. WE ALSO NOTE THAT THE
18Z NAM HAS TRENDED A BIT MORE MOIST AT LOW LVLS AT ELM TMRW
MRNG...BUT NOT AS MOIST AS THE RUC. ATTM WE WILL ADD THE POTNL FOR
BKN MVFR AT ELM TMRW MRNG...AS TRAJECTORY SUGGESTS BEST POTNL FOR
BKN CLDS WILL BE HERE. XPCT THIS LOWER DECK...IF IT WORKS INTO WRN
NY...TO BREAK UP AS THE DAY PROGRESSES...SO JUST INDICATED SCT
LOWER CLDS AT BGM/AVP TMRW. OTRW...MID/UPR DECK WILL SPREAD AND
THICKEN OVER THE REGION ON FRI. PCPN SHUD HOLD OFF TIL AFTER 00Z.
WINDS TNGT LGT SWLY...INCRSNG TO 10-20 KTS ON FRI.
.OUTLOOK...
FRI NGT...MVFR LIKELY AND IFR VSBYS PSBL IN SNOW SHOWERS WITH
COLD FRONT.
SAT TO SUN NGT...MVFR/IFR SNOW SHOWERS IN NY AND MOSTLY VFR AT
KAVP.
MON...VFR.
TUE...MVFR PSBL IFR IN LGT SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM
NEAR TERM...
SHORT TERM...RRM
LONG TERM...DGM
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
641 PM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE MAINLY CLEAR SKIES THROUGH FRIDAY
MORNING. A COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT,
BRINGING SOME SNOW SHOWERS AND MUCH COLDER AIR FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
HIGH PRES OVER THE OHIO VALLEY WILL PROVIDE CLEAR SKIES OVERNIGHT
ALONG WITH SEASONAL TEMPS. A SOUTHWEST GRADIENT WILL PREVENT TEMPS
FROM FREE FALLING BUT MINS WILL STILL RANGE FROM THE TEENS TO
LOWER 20S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
FRIDAY...A COLD FRONT WILL START DROPPING THROUGH THE UPPER GREAT
LAKES AS SFC HIGH PRES MOVES TO THE MID ATLANTIC REGION. MODELS
HAVE SLOWED PROGRESS OF THIS FRONT SO THE PERIOD WILL BE DRY WITH
JUST INCREASING MID/HIGH LEVEL MOISTURE DURING THE AFTERNOON. MAX
TEMPS WILL RANGE FROM THE MID 30S TO AROUND 40.
FRIDAY NIGHT...MODELS INDICATE SFC LOW DEVELOPING IN THE MID
ATLANTIC REGION WILL SLOW PROGRESS OF ARCTIC FRONT. FRONT WILL
CROSS AREA BETWEEN 06Z-12Z. INCREASED POPS ACROSS THE NRN CWA DUE
TO COLD FRONT AND SRN CWA DUE TO SOUTHERN SYSTEM. AFTER MIDNIGHT
HAVE LIKELY POPS NORTH AND SOUTH AND JUST HIGH CHC OVER THE
CENTRAL FA. TOTAL SNOW ACCUMS AROUND AN INCH NORTH/SOUTH AND LESS
THAN AN INCH ACROSS THE CENTRAL FA.
SATURDAY...BEHIND COLD FRONT LOW LEVEL FLOW WILL BE FROM THE
NORTHWEST BUT WITH PLENTY OF SHEAR AND SOME SFC RIDGING NOT MUCH
LAKE RESPONSE EXPECTED. WILL CONTINUE WITH CHC POPS DURING THE
MORNING WITH HIGHEST POPS THROUGH THE FINGER LAKES REGION AND
CENTRAL SOUTHERN TIER. DUE TO LOW LEVEL DRYING LOWERED POPS DURING
THE AFTERNOON. STRONG CAA WILL OCCUR THROUGHOUT THE DAY WITH TEMPS
FALLING DURING THE DAY.
SATURDAY NIGHT...SECONDARY TROF SWINGS THROUGH THE REGION LATE
NIGHT. CONDITIONS BECOME MORE FAVORABLE FOR LES AFTER MIDNIGHT
UNDER 300 FLOW. MODELS INDICATE BETTER LOW LEVEL INSTABILITY,
SYNOPTIC MOISTURE AND POSSIBLE MULTI LAKE CONNECTION. WILL RAISE
POPS TO LIKELY ACROSS NRN CWA AFTER MIDNIGHT WITH SEVERAL INCHES
OF ACCUM POSSIBLE AND JUST CHC/SLIGHT CHC ELSEWHERE. LOWS WILL
RANGE FROM THE SINGLE NUMBERS TO TEENS.
SUNDAY...BEHIND SECONDARY TROF NORTHWEST FLOW ONCE AGAIN PERSISTS
WITH POSSIBLE WELL ORGANIZED SNOW BAND LIKELY TO DROP SOUTH AND
DIMINISH. WILL HAVE CHC POPS ACROSS CENTRAL NEW YORK WITH HIGHER
POPS DURING THE MORNING HOURS. MAX TEMPS WILL GENERALLY RANGE FROM
THE LOWER TO MID 20S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
LONG TERM PD BEGINS WITH THE END OF THE CAA PTRN OF THE
WEEKEND...AND A FEW LE SNOW SHWRS OVER THE NY ZONES. TROF QUICKLY
LIFTS EAST ON MON AND ALLOWS MUCH MILDER AIR TO RETURN TO THE AREA
UNDER MAINLY CLR SKIES. BALANCE OF THE LONG TERM WILL HAVE NEAR
NRML TEMPS AND SPOTTY LGT PCPN. WEAK WV RETURNS PCPN TO THE AREA
TUE WITH ENUF MILD AIR TO BRING SOME MIXED PCPN. COLDER AIR
RETURNING BHD THE WV WITH RESULT IN SOME LGT SNOW SHWRS TUE NGT
INTO WED.
MODELS IN GOOD GNRL AGREEMENT SO TEMP AND PCPN HAS RELATIVELY HIGH
CONFIDENCE. FOR TEMPS...FLWD HPC GUID WHICH WAS IN GOOD AGREEMENT
WITH THE MEX.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
SKC/VFR CRNTLY ACRS THE FCST AREA AND CONDITIONS XPCTD TO REMAIN
UNCHANGED FOR MOST OF THE OVRNGT HRS. HOWEVER...AREA OF STRATUS
OVER OH IS CREEPING NEWD. SIG DIFFS IN THE MDLS W/RESPECT TO THESE
CLDS. RUC APPEARS TO HAVE THE BEST HANDLE ON THIS LOW LVL
MSTR...BUT ALSO STANDS OUT AS THE MDL WHICH CLEARLY BRINGS IN
THIS LOW CLD INTO WRN SXNS BY MRNG. CORRESPONDINGLY...HRRR CIG
DATA SHOWS MVFR INTO STEUBEN COUNTY 09-10Z. WE ALSO NOTE THAT THE
18Z NAM HAS TRENDED A BIT MORE MOIST AT LOW LVLS AT ELM TMRW
MRNG...BUT NOT AS MOIST AS THE RUC. ATTM WE WILL ADD THE POTNL FOR
BKN MVFR AT ELM TMRW MRNG...AS TRAJECTORY SUGGESTS BEST POTNL FOR
BKN CLDS WILL BE HERE. XPCT THIS LOWER DECK...IF IT WORKS INTO WRN
NY...TO BREAK UP AS THE DAY PROGRESSES...SO JUST INDICATED SCT
LOWER CLDS AT BGM/AVP TMRW. OTRW...MID/UPR DECK WILL SPREAD AND
THICKEN OVER THE REGION ON FRI. PCPN SHUD HOLD OFF TIL AFTER 00Z.
WINDS TNGT LGT SWLY...INCRSNG TO 10-20 KTS ON FRI.
.OUTLOOK...
FRI NGT...MVFR LIKELY AND IFR VSBYS PSBL IN SNOW SHOWERS WITH
COLD FRONT.
SAT TO SUN NGT...MVFR/IFR SNOW SHOWERS IN NY AND MOSTLY VFR AT
KAVP.
MON...VFR.
TUE...MVFR PSBL IFR IN LGT SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RRM
NEAR TERM...RRM
SHORT TERM...RRM
LONG TERM...DGM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
321 AM EST WED FEB 8 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH LATER TODAY. HIGH PRESSURE WILL
BUILD IN THROUGH THURSDAY AND WILL WEAKEN ON FRIDAY. A STRONG COLD
FRONT WILL MOVE ACROSS THE AREA SATURDAY. ARCTIC AIR MASS WILL
SETTLE IN FOR THE LATTER HALF OF THE WEEKEND AS HIGH PRESSURE
BUILDS IN. COLD AND DRY HIGH PRESSURE WILL MOVE EAST OVER THE AREA
THROUGH MONDAY SHIFTING OFF SHORE BY TUESDAY ALLOWING FOR A
WARMING TREND TO BEGIN BY MID WEEK NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE OVER THE CENTRAL PLAINS
CONTROLS THE WEATHER OVER THE EASTERN 2/3RDS OF THE NATION. WEAK LOW
PRESSURE IS ATTEMPTING TO ORGANIZE OFF THE SOUTHEAST COAST WITHIN A
LOW-LEVEL BAROCLINIC ZONE. THE CAROLINAS ARE CURRENTLY WITHIN A
WEAK PRESSURE GRADIENT EXTENDING NORTHWEST FROM THE LOW OFFSHORE
TOWARD AN UPPER LEVEL DISTURBANCE OVER THE MID-MISSISSIPPI VALLEY.
THE UPPER DISTURBANCE WILL PASS EAST THROUGH VIRGINIA THIS AFTERNOON
AND OFFSHORE THIS EVENING.
THERE WILL BE NO LOW-LEVEL MOISTURE TO SPEAK OF INVOLVED WITH THIS
SYSTEM...HOWEVER THE GFS SHOWS AN IMPRESSIVE SLUG OF 400-250 MB
MOISTURE CROSSING THE AREA LATER THIS MORNING THROUGH THE AFTERNOON
HOURS. THIS SHOULD LEAD TO CIRRUS CLOUD COVER PERHAPS NOT QUITE AS
THICK AND OPAQUE AS OBSERVED YESTERDAY. THERE MAY ALSO BE A SEVERAL-
HOUR LONG PERIOD OF ALTOCUMULUS AROUND MIDDAY ASSOCIATED WITH A
SHALLOW AND TRANSIENT AREA OF MOISTURE AT THE 700 MB LEVEL. ALL THIS
POTENTIAL FOR CLOUD COVER ARGUES FOR HIGH TEMPERATURES CLOSER TO THE
COOLER GFS NUMBERS TODAY...UPPER 50S TO AROUND 60 AREA-WIDE EXCEPT
FOR SOME LOWER 60S IN THE KINGSTREE/GEORGETOWN CORRIDOR. THE COOLER
GFS NUMBERS WORKED OUT MUCH BETTER WITH YESTERDAY`S CIRRUS CANOPY.
AS THE UPPER DISTURBANCE PUSHES THROUGH VIRGINIA THIS AFTERNOON A
SURFACE COLD FRONT WILL PUSH SOUTHEAST THROUGH OUR AREA. MODEST COLD
ADVECTION BEHIND THE FRONT WILL CONTINUE THROUGH THE NIGHT WITH
CLEARING SKIES. LOWS SHOULD REACH THE MID 30S MOST AREAS WITH SOME
UPPER 30S AT THE IMMEDIATE COAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL BUILD IN THROUGH THURSDAY
AS HIGH SHIFTS DOWN OVER THE LOWER MISSISSIPPI VALLEY WITH COOL
AND DRY AIR MOVING IN. BY FRI THE HIGH WEAKENS AND A DEEPER
RETURN FLOW SETS UP AS MID TO UPPER TROUGH BEGINS TO DIG DOWN OVER
THE CONUS PUSHING A NORTHERN STREAM COLD FRONT EAST AND EXTENDING
DOWN INTO THE CAROLINAS BY THE END OF THE PERIOD. OVERALL DRY AIR
MASS IN PLACE WITH PCP WATER VALUES DOWN LOWER THAN A HALF INCH
BUT WILL SEE A SLIGHT RISE IN MOISTURE IN THE RETURN FLOW ON FRI.
BY FRI EVENING VALUES WILL REACH UP NEAR .75 INCHES. NOT EXPECTING
ANY PCP WITH ONLY SOME HIGH CLOUDS AT TIMES.
WINDS WILL BEGIN TO BACK SLOWLY THROUGH THURS INTO FRIDAY. BEST
CAA WILL SHUT OFF THURS MORNING AND 850 TEMPS SHOWING A MINIMAL
RISE THROUGH FRI. WITH VERY WEAK GRADIENT ON THURS NIGHT SHOULD
SEE DECENT RADIATIONAL COOLING ALTHOUGH THERE WILL BE SOME HIGH
CLOUDS PASSING OVERHEAD. OVERNIGHT LOWS WILL BE DOWN AROUND
FREEZING. EXPECT HIGHS ON THURS TO ONLY REACH THE MID 50S BUT
READINGS SHOULD BE UP AROUND 60 BY FRI AFTN.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...COLD FRONT WILL SWEEP ACROSS AREA SAT
MORNING AS MID TO UPPER TROUGH DIGS DOWN INTO THE SOUTHEAST WHILE
MOVING EAST. A DEEP N-NW FLOW WILL SET UP BY SUNDAY AS MID TO
UPPER TROUGH AXIS SWINGS OFF THE COAST AS HIGH PRESSURE BUILDS IN
THROUGH THE REMAINDER OF THE WEEKEND. WILL TAP INTO MUCH COOLER
AND DRIER AIR MASS BY SUN AS 850 TEMPS DROP OUT FROM UP AROUND 4 C
SAT MORNING DOWN BELOW -5 C THROUGH SUN MORNING. HIGH TEMPS ON
SUNDAY WILL NOT MAKE IT OUT OF THE 40S ACROSS MOST PLACES AS
DEWPOINT TEMPS DROP DOWN INTO THE TEENS UNDER FULL SUNSHINE.
ALTHOUGH MAX CAA WILL END ON SUNDAY...BETTER RADIATIONAL COOLING
CONDITIONS SUNDAY NIGHT WILL BRING OVERNIGHT LOWS DOWN INTO THE
20S AND MAY EVEN REACH DOWN INTO THE TEENS IN TRADITIONALLY COOLER
SPOTS. WITH A COOL START MONDAY TEMPS WILL REBOUND UP NEAR 50
UNDER SUNNY SKIES AS NEUTRAL TO WEAK WAA BEGINS.
AS HIGH SHIFTS NEARLY OVERHEAD MON NIGHT AND THEN JUST OFF SHORE
BY TUES MORNING...EXPECT ANOTHER COLD NIGHT WITH IDEAL RADIATIONAL
COOLING EVEN THOUGH WEAK WAA WILL SET UP BY MORNING. SHOULD SEE
OVERNIGHT LOWS BELOW FREEZING ONCE AGAIN AS MOISTURE BEGINS TO
CREEP BACK UP. WARMING TREND WILL CONTINUE THROUGH MID WEEK AS
HIGH CONTINUES TO MOVE FURTHER OFF SHORE AND A DEEPER SOUTHERLY
RETURN FLOW SET UP.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...CLR SKIES EXPECTED EARLY THIS MORNING PERHAPS SOME
INCREASING THIN CIRRUS TOWARDS SUNRISE. GOOD RADIATIONAL
COOLING IS NOW OCCURRING WITH TEMPERATURE/DEWPOINT SPREADS
NARROWING. FORECAST NAM BUFR SOUNDING PROFILES CONTINUE TO SHOW
FAVORABLE PROFILES FOR FOG...BUT RUC PROFILES ARE MUCH DRIER IN THE
LOWEST 1000 FEET WHICH WOULD BE UNSUPPORTIVE OF IFR VSBYS. MOISTURE
IS LIMITED AND VERY SHALLOW BUT VERY DRY AIR IS NOTED ABOVE THE
INVERSION. NUMERICAL GUIDANCE INDICATES CALM SFC WINDS THROUGH
SUNRISE WITH VFR VISIBILITIES. CONFIDENCE IN SHALLOW GROUND FOG
DEVELOPMENT HAS INCREASED...THUS EXPECT MVFR VISIBILITIES TO DEVELOP
AT ALL TERMINALS THIS MORNING. THERE IS LOW CONFIDENCE THAT AT THE
LBT AND CRE TERMINALS IFR VISIBILITY COULD DEVELOP MAINLY AFTER
09Z...BUT FOR NOW THIS POTENTIAL IS NOT EXPLICIT IN THE FORECAST.
AFTER SUNRISE EXPECT INCREASING MID-LEVEL CLOUDS AT FLO/LBT AND BY
MID-MORNING AT THE COASTAL TERMINALS. LIGHT NORTHEAST WINDS WILL
BECOME WEST-NORTHWEST MID-LATE MORNING AT FLO/LBT AND AT THE COASTAL
TERMINALS IN THE AFTERNOON AS A SURFACE TROUGH MOVES THROUGH.
EXTENDED OUTLOOK...LOW CONFIDENCE FOR IFR/MORNING FOG FRIDAY. SLIGHT
CHANCE RAIN SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...WEAK LOW PRESSURE IS ATTEMPTING TO ORGANIZE
OFF THE FLORIDA EAST COAST THIS MORNING...WHILE SPRAWLING HIGH
PRESSURE OVER THE MID-SECTION OF THE NATION SLOWLY MOVES EAST. A DRY
COLD FRONT JUST WEST OF THE APPALACHIANS WILL MOVE EAST AND ACROSS
THE WATERS THIS AFTERNOON...TURNING OUR LIGHT NORTH TO NORTHEAST
WINDS NORTHWESTERLY. THE FLORIDA LOW WILL LINK UP WITH THIS FRONT
AND SHOOT NORTHEAST AND OUT OF SEA LATER TODAY. OUR WIND SPEEDS WILL
SURGE TO A SOLID 15 KNOTS TONIGHT WITH SOME GUSTS TO 20 KNOTS
POSSIBLE. SEAS ARE CURRENTLY ONLY 2-3 FEET WITH THE MAJORITY OF THE
WAVE ENERGY AN EASTERLY SWELL. SHORT-PERIOD WAVES WILL INCREASE
TONIGHT WITH THE STRONGER OFFSHORE FLOW DEVELOPING...WITH SEAS
BUILDING T0 3-4 FT 10-20 MILES FROM SHORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL BUILD IN ON THURS BUT WILL
WEAKEN LATE THURS THROUGH FRIDAY BEFORE MID TO UPPER TROUGH DIGS
DOWN INTO THE CONUS DRAGGING A STRONG COLD FRONT TOWARD WATERS BY
END OF THE PERIOD. WILL SEE DIMINISHING OFF SHORE FLOW AS CAA ENDS
EARLY THURS. N-NW WINDS UP AROUND 15 KTS WILL QUICKLY DIMINISH
THROUGH THURS MORNING. WINDS WILL BECOME VERY LIGHT AS HIGH
PRESSURE WEAKENS THROUGH THURS NIGHT BUT WILL EVENTUALLY PICK UP
AGAIN ON FRI AS RETURN FLOW SETS UP AHEAD OF NEXT SYSTEM. BY FRI
NIGHT SOUTHERLY WINDS WILL INCREASE UP NEAR 15 KTS AND WILL
INCREASE FURTHER AS BEFORE THEY VEER AROUND THROUGH SAT MORNING AS
COLD FRONT APPROACHES THE WATERS FROM THE WEST. SEAS AROUND 2 TO 3
FT TO START WILL DROP DOWN TO 1 TO 2 FT THROUGH EARLY FRI. AS
RETURN FLOW INCREASES THROUGH FRI NIGHT...SEAS WILL INCREASE UP TO
2 TO 4 FT BY END OF PERIOD.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...
WINDS WILL INCREASE AS THEY VEER AROUND TO THE W-NW IN TIGHTENED
GRADIENT FLOW AS COLD FRONT MOVES THROUGH SAT. EXPECT WINDS UP
AROUND NEAR 15 TO 20 KTS AS COLD FRONT MOVES THROUGH AND THEN
SHOULD SEE A BIT OF DROP BEFORE MAJOR COLD SURGE SAT NIGHT INTO
SUNDAY WITH NORTHERLY WINDS INCREASING UP TO 25 KTS. THESE STRONG
NORTHERLY WINDS WILL DRIVE SEAS UP TO 4 TO 6 FT THROUGH SUN
MORNING. LATEST WNA SHOW SEAS WINDS AND SEAS REACHING SCA
THRESHOLDS FOR A FEW HOURS EARLY SUNDAY. AS CAA CUTS OFF AND
GRADIENT WEAKENS THROUGH LATE SUNDAY...WINDS WILL DIMINISH TO 10
TO 15 KTS AS THEY VEER SLOWLY AROUND TO THE N-NE BY MONDAY
MORNING. SEAS WILL DROP DOWN TO 3 FT OR LESS BY MONDAY MORNING.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1230 AM EST WED FEB 8 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD FROM THE WEST FOR MUCH OF THE
WEEK...KEEPING CONDITIONS DRY WITH TEMPERATURES NEAR NORMAL FOR THIS
TIME OF THE YEAR. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA
SATURDAY...WITH MUCH COOLER CONDITIONS EXPECTED INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 1230 AM WEDNESDAY...CLEAR SKIES AND CALM WINDS ACROSS THE AREA
HAVE LED US TO LOWER THE LOW TEMPERATURE FORECASTS BY 1-3 DEGREES
FOR THE REMAINDER OF THE OVERNIGHT PERIOD. LOWER TO MID 30S ARE
EXPECTED INLAND...WITH UPPER 30S TO LOWER 40S AT THE IMMEDIATE
COAST. RADIATIONAL COOLING CONDITIONS ARE VERY GOOD CURRENTLY AND
INCREASING HIGH THIN CIRRUS LATE WILL DO LITTLE TO OFFSET THAT.
THERE IS SOME POTENTIAL FOR SHALLOW GROUND FOG TO DEVELOP BUT IT
APPEARS TOO ISOLATED AT THIS TIME FOR INCLUSION IN THE FORECAST.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE WILL BE THE MAIN THEME OF THE
SHORT TERM PERIOD. WEAK HIGH PRESSURE IN PLACE WED WILL BE PUSHED
EAST AS A FAIRLY IMPRESSIVE SHORTWAVE PASSES NORTH OF THE AREA LATER
TOMORROW. DRY COLD FRONT EXTENDING SOUTH THE SURFACE WAVE ASSOCIATED
WITH SHORTWAVE PUSHES ACROSS THE AREA WED AFTERNOON. SOUNDINGS DO
SHOW A MARGINAL INCREASE IN MID LEVEL MOISTURE IN THE SOUTHWEST FLOW
AHEAD OF THE WAVE WHICH WILL INCREASE MID LEVEL CLOUD COVER. THE
LAYER UNDER 7K FT HOWEVER LOOKS TOO DRY FOR ANY PRECIP. COMBINATION
OF SUN...ESPECIALLY EARLY IN THE DAY...AND MODIFYING AIR MASS WILL
RESULT IN HIGHS A FEW DEGREES ABOVE CLIMO...LOW 60S. COLD ADVECTION
BEHIND THE FRONT WILL DROP TEMPS WED NIGHT...BUT COLD ADVECTION IS
NOT PARTICULARLY STRONG. LOWS WILL END UP CLOSE TO CLIMO.
CANADIAN HIGH BUILDS IN FROM THU AND THU NIGHT WITH TEMPS DROPPING
BACK TO CLIMO. DROPPED HIGHS A COUPLE DEGREES THU BUT MAY NOT BE
ENOUGH. WEAK COLD ADVECTION WILL CONTINUE INTO THE AFTERNOON HOURS
AND WILL HELP OFFSET SOME OF THE WARMING UNDER MOSTLY SUNNY SKIES.
WINDS CLOSE TO 20 KT NEAR THE TOP OF THE MIXED LAYER MAY END UP
MIXING DOWN IN THE FORM OF 15 TO 20 MPH GUSTS THU AFTERNOON. SURFACE
RIDGE AXIS SETTLES OVER THE AREA THU NIGHT WITH NORTHERLY FLOW
BECOMING CALM. ALTHOUGH THERE MAY BE SOME HIGH CLOUD COVER OVERNIGHT
LOW/MID LEVEL DRY AIR IN CONJUNCTION WITH CALM WINDS WILL RESULT IN
SOME RADIATIONAL COOLING. DROPPED LOWS A COUPLE DEGREES BUT MAY NEED
MORE REDUCTION. CURRENT FORECAST IS LOWS NEAR TO SLIGHTLY BELOW
CLIMO.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...OTHER THAN A DRY...BUT ARCTIC...COLD FRONT
SATURDAY...QUIET WEATHER TO PERSIST THROUGH THE LONG TERM. BROAD
500MB TROUGHING ACROSS THE EAST WILL AMPLIFY SATURDAY AS A STRONG
S/W PUSHES A COLD FRONT THROUGH THE CAROLINAS. MOISTURE RETURN AHEAD
OF THIS FRONT IS QUITE LIMITED...SO FROPA IS EXPECTED TO BE DRY. LOW
LEVEL THICKNESSES AND 500MB HEIGHTS PLUMMET BEHIND THE
BOUNDARY...AND HAVE TRIED TO SHOW A NON-TYPICAL DIURNAL CURVE
SATURDAY WITH MAX TEMPS BEING REACHED LATE MORNING. TRUE WINTER-LIKE
AIR ARRIVES SUNDAY AND MONDAY WITH TEMPS AVERAGING AROUND 10 DEGREES
BELOW NORMAL...WITH LOWS IN THE 20S BOTH MORNINGS AND HIGHS SUNDAY
ONLY AROUND 50 DEGREES. TEMPS BEGIN TO MODERATE TO SEASONABLE NORMS
TUESDAY AND A STORM SYSTEM MAY BEGIN TO TAKE SHAPE ACROSS THE
SOUTHEAST...BUT THIS FAR OUT WILL KEEP FORECAST DRY THROUGH THE
EXTENDED.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...CLR SKIES EXPECTED EARLY THIS MORNING PERHAPS SOME
INCREASING THIN CIRRUS TOWARDS SUNRISE. GOOD RADIATIONAL
COOLING IS NOW OCCURRING WITH TEMPERATURE/DEWPOINT SPREADS
NARROWING. FORECAST NAM BUFR SOUNDING PROFILES CONTINUE TO SHOW
FAVORABLE PROFILES FOR FOG...BUT RUC PROFILES ARE MUCH DRIER IN THE
LOWEST 1000 FEET WHICH WOULD BE UNSUPPORTIVE OF IFR VSBYS. MOISTURE
IS LIMITED AND VERY SHALLOW BUT VERY DRY AIR IS NOTED ABOVE THE
INVERSION. NUMERICAL GUIDANCE INDICATES CALM SFC WINDS THROUGH
SUNRISE WITH VFR VISIBILITIES. CONFIDENCE IN SHALLOW GROUND FOG
DEVELOPMENT HAS INCREASED...THUS EXPECT MVFR VISIBILITIES TO DEVELOP
AT ALL TERMINALS THIS MORNING. THERE IS LOW CONFIDENCE THAT AT THE
LBT AND CRE TERMINALS IFR VISIBILITY COULD DEVELOP MAINLY AFTER
09Z...BUT FOR NOW THIS POTENTIAL IS NOT EXPLICIT IN THE FORECAST.
AFTER SUNRISE EXPECT INCREASING MID-LEVEL CLOUDS AT FLO/LBT AND BY
MID-MORNING AT THE COASTAL TERMINALS. LIGHT NORTHEAST WINDS WILL
BECOME WEST-NORTHWEST MID-LATE MORNING AT FLO/LBT AND AT THE COASTAL
TERMINALS IN THE AFTERNOON AS A SURFACE TROUGH MOVES THROUGH.
EXTENDED OUTLOOK...LOW CONFIDENCE FOR IFR/MORNING FOG FRIDAY. SLIGHT
CHANCE RAIN SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM WEDNESDAY...VERY FEW CHANGES NEEDED TO THE PREVIOUS
FORECAST EARLY THIS MORNING. NORTH TO NORTHEAST SURFACE WINDS WILL
CONTINUE OVERNIGHT...5-10 KT NEAR THE COAST WITH 10-15 KT WINDS
FARTHER OFFSHORE. SEAS ARE GENERALLY 2-3 FEET.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM MONDAY...FLOW WILL REMAIN NORTHERLY THROUGH THE PERIOD.
NORTHEAST WINDS WED BACK TO NORTHWEST WED NIGHT FOLLOWING PASSAGE OF
COLD FRONT LATE IN THE DAY. ALONG WITH THE SHIFT TO OFFSHORE SPEEDS
WILL PICK UP AS COLD ADVECTION DEVELOPS. POST FRONT THERE WILL BE A
SLIGHT PINCH TO THE GRADIENT...BUT WITH LIMITED COLD ADVECTION
OFFSHORE FLOW SHOULD BE LIMITED TO A SOLID 15 KT. SEAS 2 TO 3 FT WED
WILL CONTINUE INTO WED NIGHT BUT MAY TOUCH 4 FT LATE WED NIGHT WELL
AWAY FROM SHORE GIVEN THE OFFSHORE COMPONENT. NORTHERLY FLOW WILL
START TO DECREASE THU AND CONTINUE THU NIGHT AS SURFACE RIDGE AXIS
SETTLES SOUTH. SEAS WILL DROP TO 2 FT OR SE BY THE END OF THE PERIOD.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...DIFFUSE PRESSURE GRADIENT FRIDAY CONTRIBUTES
TO LIGHT AND VARIABLE WINDS AND SEAS OF ONLY 1-2 FT. WINDS GRADUALLY
BECOME SW IN A PRE-FRONTAL REGIME LATE FRIDAY...AND INCREASE TO
10-15 KTS EARLY SATURDAY AS GRADIENT TIGHTENS AHEAD OF A STRONG COLD
FRONT. WITH LACK OF ANY MEANINGFUL SWELL PRESENT IN THE
SPECTRUM...WAVE CONDITIONS WILL BE DOMINATED BY 5 SEC SW WIND
WAVES...WITH AMPLITUDES RISING TO 3-4 FT BY SAT MORNING. A SHORT
DECREASE IN SEAS OCCURS DURING THE AFTN AS WINDS VEER TO THE NORTH
WITH THE FROPA...BUT RISE QUICKLY AGAIN LATE SAT...AND ESPECIALLY
SUN AS STRONG COLD AIR ADVECTION COMMENCES. NORTH WINDS INCREASE TO
20 KTS AND SEAS BUILD TO 4-5 FT...WITH SCEC CRITERIA CONDITIONS
LIKELY DURING MUCH OF THE DAYLIGHT HOURS SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...LEBO
LONG TERM...WEISS
AVIATION...ROSS/TRA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
955 AM CST WED FEB 8 2012
.DISCUSSION...LOW-LEVEL STRATUS REMAINS ENTRENCHED ACROSS
NORTHWESTERN NORTH DAKOTA THIS MORNING. THE HRRR CONTINUES TO BE
THE SUPERIOR MODEL WITH RESPECT TO THE AREAL EXTENT AND EVOLUTION
OF LOW-LEVEL MOISTURE. AS A RESULT...WILL CONTINUE TO FORECAST
CLOSE TO ITS SOLUTION TODAY.
THE HRRR INDICATES THE STRATUS DECK WILL PIVOT ANTICYCLONICALLY
THROUGH THE REMAINDER OF THE MORNING AND BREAK UP THIS AFTERNOON
AS SYNOPTIC SUBSIDENCE OVERSPREADS THE REGION AND MIXES DRIER AIR
ALOFT TO THE SURFACE. THIS WILL CREATE A SLOWER WARM UP NORTH.
HAVE UPDATED THE FORECAST TO INDICATE THIS SLOWER TREND.
OTHERWISE...THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED TEXT PRODUCTS WILL BE OUT SHORTLY.
&&
.AVIATION...MVFR-IFR CLOUDINESS IN THE NORTHWEST WITH CEILINGS
FALLING TO IFR AT WILLISTON DURING THE PAST HOUR. EXPECT THESE
CEILINGS TO CONTINUE INTO THE MID MORNING BEFORE DISSIPATING.
ELSEWHERE VFR CONDITIONS ARE EXPECTED. LIGHT WINDS THIS MORNING
WILL BECOME SOUTH TO SOUTHWEST THIS AFTERNOON AND TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TM...UPDATE
NH...AVIATION
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
109 AM EST WED FEB 8 2012
.SYNOPSIS...
LOW PRESSURE BRINGS RAIN AND SNOW LATE TONIGHT AND WEDNESDAY...WITH
LIGHT SNOW ACCUMULATION POSSIBLE NORTH. HIGH PRESSURE BUILDS IN
THURSDAY. ARCTIC COLD FRONT FRIDAY NIGHT FOR COLDER WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATED...
IN PROCESS OF PREPARING THE EARLY MORNING PACKAGE. CHANGES THUS
FAR TO POPS BASED ON UPSTREAM OBS...LATEST HRRR AND NAM SIMULATED
REFLECITIVITY COMBINED WITH LIFT/OMEGA FIELDS. STILL LOOKS LIKE
PCPN WILL INITIALLY FALL OUT OF MID DECK WHICH WILL GO TO
SATURATED THE COLUMN BLO. LOOKS LIKE SW VA AND SE OH MAY GET IN ON
ACTION FIRST...WITH SE OH BEING MORE INTO DEFORMATION AXIS TO
START. WILL BRING LKLY POPS ENTERING SE OH FROM W AT 12Z...AND
ALSO SW VA COUNTIES. SEE TWO MAIN AREAS OF PCPN...ONE WITH
DEFORMATION ACROSS SE OH AND ANOTHER STREAKING N UP THE MTN
CHAIN...WITH PCPN FILLING IN ACROSS THE LOWLANDS AS UPR LOW
APPROACHES. HAVENT GOT TO TEMPS YET WHICH IS THE CRITICAL PIECE
FOR DETERMINING PCPN TYPE. TEMPS AS OF 06Z HAVE ALREADY DIPPED
INTO LWR 30S OUTSIDE OF THE MTNS...WITH 20S SHOWING UP IN THE HIGH
TERRAIN. STILL LOOKING AT A QUICK HITTER...WITH SYS PULLING E BY
21Z OR SO.
PREVIOUS DISCUSSION BELOW...
LOW PRESSURE SYSTEM BRINGS RAIN AND SNOW LATE TONIGHT AND
WEDNESDAY. THIS SYSTEM IS STRONG ENOUGH TO INDUCE AN INVERTED
SURFACE TROUGH WEDNESDAY MORNING JUST WEST OF THE MOUNTAINS...THEN
THE COLD AIR COLLAPSES IN LATER IN THE DAY. THUS...WE HAVE A
TYPICAL WARM WEDGE JUST WEST OF THE MOUNTAINS WEDNESDAY MORNING
INTO EARLY WEDNESDAY AFTERNOON. WHILE THE TEMPS ALOFT...850 MB AND
ABOVE...ARE COLD ENOUGH FOR SNOW...EVEN IN THE WARM WEDGE...THE
BOUNDARY LAYER TO 925 MB WILL BE WARM ENOUGH FOR MAINLY A RAIN AND
SNOW MIX OVER MUCH OF THE AREA FOR THE BULK OF THE
PRECIPITATION...WHICH TAPERS OFF LATER IN THE DAY FROM WEST TO
EAST. THE MODELS DEPICT THIS NICELY...EVEN THOUGH THE GFS IS A BIT
WARMER WITH THE SURFACE TEMPS WEDNESDAY. WE EXPECT TEMPS TO BOTTOM
OUT BEFORE THE THICK CLOUDS MOVE IN LATER TONIGHT...SO A BIT OF A
RISE BEFORE DAWN. MODEL GUIDANCE IS CLOSE TONIGHT AND ACCEPTED. A
COMPROMISE LOOKS THE WAY TO GO WITH SURFACE TEMPS
WEDNESDAY...WHICH OUR FORECAST HAS TEMPS ABOVE FREEZING FOR MUCH
OF THE DAY...EXCEPT IN THE HIGHER ELEVATIONS OF THE NORTHERN
MOUNTAINS. NOT MUCH MOISTURE TO WORK WITH...BUT DYNAMICS WILL BE
STRONG ENOUGH TO SQUEEZE OUT A TENTH OR TWO OF LIQUID.
STILL...WITH MARGINAL TEMPS MOST AREAS...RELATIVELY WARM GROUND
AND PRECIP FALLING DURING THE DAY...SNOW ACCUMULATIONS WILL BE
LIMITED. WE LOOK FOR SNOW ACCUMULATIONS TO RANGE FROM POSSIBLY AN
INCH ACROSS THE NORTHWEST PART OF THE AREA TO A FEW INCHES IN THE
HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS. THUS...NO ADVISORY
CRITERIA MET.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
WITH THE 850 MB THERMAL TROF HOLDING INTO THURSDAY MORNING...HAVE
LOW CONFIDENCE IN TIMING THE CLEARING OF THE LINGERING LOW LEVEL
CLOUD DECK.
TRIED TO SLOW THE CLEARING DOWN...AND LEAVE POPS HIGHER IN THE
MOUNTAINS LONGER...INTO WEDNESDAY NIGHT. SNOW ACCUMULATIONS FOR
OVERNIGHT AN INCH OR LESS FIGURED...AND MOISTURE THINS.
THE 850 TO 925 MB WIND FLOW BECOMES WEAKER BY 12Z THURSDAY...SO
CONCERNED THE CLOUDS MAY HOLD LONGER ON THURSDAY...ESPECIALLY FROM
CRW ON SOUTH THROUGH THE SOUTHERN COAL FIELDS OF WEST VIRGINIA INTO
SOUTHWEST VIRGINIA ON THURSDAY.
HIGH PRESSURE IN VICINITY THURSDAY NIGHT INTO FRIDAY MORNING.
MOISTURE AND WINDS STILL INCREASE AHEAD OF THE ARCTIC FRONT FRIDAY
AFTERNOON. HAVE CHANCE POPS INCREASES FROM NW TO SE 18Z FRIDAY TO
00Z SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ARCTIC FRONT SLICES THROUGH FRIDAY NIGHT AND SATURDAY WITH A ROUND
OF RAIN/SNOW SHOWERS QUICKLY TURNING TO ALL SNOW INTO THE EARLY
MORNING HOURS SATURDAY. STOUT COLD AIR ADVECTION BEHIND THE SYSTEM
WILL BRING A SPELL OF CHILLIER AIR...BELOW NORMAL VALUES FOR THIS
TIME OF YEAR. WEEKEND OVERNIGHT PERIODS WILL CARRY THE POTENTIAL FOR
EFFICIENT RADIATIONAL COOLING GIVEN THE CLEAR NIGHTS EXPECTED. WILL
NEED TO MONITOR SNOWFALL FROM THE FRONT...AS THIS COULD ENHANCE THE
COOLING. AS IT IS...HAVE GONE AGGRESSIVE IN THE OVERNIGHT LOWS
SATURDAY NIGHT FOR THE MOUNTAIN VALLEYS. COLD AIRMASS WILL NOT BE IN
A HURRY TO MODERATE OR LIFT OUT...AND WILL STAY BELOW NORMAL THROUGH
THE REMAINDER OF THE WEEKEND. WILL SEE A SLOW TICK UPWARDS IN THE
TEMPERATURES INTO EARLY NEXT WEEK.
LOW CONFIDENCE WITH A SURFACE TROUGH AFFECTING THE SOUTHERN
MOUNTAINS LATE MONDAY AND MONDAY NIGHT...AND DO NOT SEE MUCH IN THE
WAY OF CONSENSUS WITH THIS IN THE OPERATIONAL LONG TERM MODELS. WILL
CAP THE POPS AT LOW CHANCE...BUT EXPECT SOME CHANGE TO THIS PART OF
THE FORECAST OVER THE NEXT FEW MODEL RUNS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
LOW END VFR STRATUS HANGING OVER SE OH WITH SOME MID/HI CLDS
INVADING FROM W AS OF 06Z. THIS WILL CONT TO BE CASE THRU
09Z...WITH STRATUS HOLDING FIRM ACROSS SE OH WITH REMAINDER OF
AREA SCT-BKN 8 TO 10 THSND FT CLDS.
CIGS WILL LWR INTO IFR TOWARD 12Z WITH PCPN ENTERING SW VA...FAR
WESTERN ZONES AND SE OH IN THE FORM OF -SN SE OH AND MORE OF A
RASN MIX NE KY AND SW VA. VSBY DEPENDANT ON FORM OF PCPN WITH SOME
2SM VSBY OR IN SN AND 3 TO 4 IN AREAS THAT MIX. THIS TREND EXPANDS
N AND E THRU 18Z...BEFORE PCPN CONFINES ITSELF TO MAINLY
CENTRAL/NORTHERN MTNS BY 21Z AS UPR LOW PULLS AWAY. LOW
CONFIDENCE..BUT FIGURE ON MIX CENTRAL AND SOUTHERN LOWLANDS WITH
SN ACROSS NORTH AND IN MTNS. GIVEN THE UNCERTAINITY IN PCPN TYPE
WENT WITH MORE OF A GENERAL 2SM VSBY AND 800 TO 1000FT CIGS IN
TAFS. COULD SEE SOME LOCAL LIFR VSBY IN ANY HEAVIER SNOWS...MOST
LKLY ACROSS THE MTNS AND PERHAPS SE OH.
AS SYS PULLS E THIS AFTN...LOW STRATUS WILL LINGER IN ITS
WAKE...WITH IFR CIGS FOR ALL TAF SITES THRU 06Z THU.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: CIGS AND VSBY COULD VARY BETWEEN MVFR AND
IFR OUTSIDE OF THE MTNS...DEPENDANT ON PCPN TYPE.
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 WED 02/08/12
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 H H H H H M L L L L
HTS CONSISTENCY H H H H H M M M L L L L
BKW CONSISTENCY H H H H H H H M M M L L
EKN CONSISTENCY H H H H H H H M L M M L
PKB CONSISTENCY M M M M M M M M L L L L
CKB CONSISTENCY H H H H H H H H M L L L
AFTER 06Z THURSDAY...
IFR CONDITIONS POSSIBLE IN THE MOUNTAINS AND LOWLAND COUNTIES
IMMEDIATELY ADJACENT WEDNESDAY NIGHT. IFR AGAIN POSSIBLE IN SNOW
SHOWERS FRIDAY NIGHT THROUGH SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/26/JMV
NEAR TERM...JMV/30
SHORT TERM...KTB
LONG TERM...26
AVIATION...30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
550 PM EST WED FEB 8 2012
.SYNOPSIS...
A STRONG UPPER LEVEL SYSTEM CROSSING THE MID-ATLANTIC REGION THIS
AFTERNOON WILL MOVE OFFSHORE LATE TONIGHT INTO EARLY THURSDAY.
HIGH PRESSURE OVER THE MID MISSISSIPPI VALLEY WILL SLIDE EAST TO
THE CAROLINA COAST THROUGH FRIDAY...PROVIDING FAIR AND DRY
WEATHER IN PENNSYLVANIA FOR THE END OF THE WEEK. AN AMPLIFYING
UPPER LEVEL TROUGH OVER THE EASTERN U.S. WILL SEND A STRONG COLD
FRONT SOUTHEAST ACROSS THE STATE FRIDAY NIGHT...ALLOWING MODIFIED
ARCTIC AIR TO POUR INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
EVENING WV LOOP SHOWS THE MID LVL SHORTWAVE RESPONSIBLE FOR THE
LGT SNFL PIVOTING EWD INTO SOUTHWEST PA. THE BEST AREA OF
ENHANCED LIFT VIA LEFT EXIT REGION UPPER JET DYNAMICS APPEARS TO
BE SHIFTING EAST OF PA IN VICINITY OF DEVELOPING COASTAL LOW. OVER
THE LAST COUPLE OF HOURS RADAR RETURNS HAVE BECOME MARKEDLY
LIGHTER ACROSS CENTRAL PA. 22Z RUC ANALYSIS SHOWS AN INVERTED SFC
TROUGH EXTENDING NWD ALONG THE ALLEGHENIES FROM A DEVELOPING 1014MB
LOW E OF CAPE HATTERAS. MDL QPF/S ARE IN GOOD AGREEMENT WITH AN
ADDITIONAL 0.05 INCHES OR SO ACROSS THE LOWER SUSQ VALLEY AND
EVEN LIGHTER AMTS FURTHER WEST. WITH SNOW/WATER RATIOS ARND
13/1...THIS WILL TRANSLATE TO ADDITIONAL ACCUMS UP TO AN INCH OVR
THE SE ZONES. THE LAST OF THE LGT SNOW SHOULD BE OVER BY
MIDNIGHT...AS LG SCALE SUBSIDENCE OVERSPREADS THE REGION IN WAKE
OF DEPARTING MID LVL SHORTWAVE.
WEBCAMS INDICATE THAT SNOW HAS ACCUMULATED MAINLY ON THE GRASSY
SFCS...AS ROAD TEMPERATURES/TIME OF DAY HAVE BEEN LIMITING
FACTORS. A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE
LAUREL HIGHLANDS AND S-CENTRAL MTNS WITH STORM TOTALS BETWEEN 2-4
INCHES...WITH THE HIGHEST AMTS ON THE RIDGES WEST OF RT 219. PHL
ISSUED AN IMPACT-BASED ADVISORY /1-2" FOR THE EVE COMMUTE/ AND LWX
HAS LOWER ADVY CRITERIA. THIS EXPLAINS THE GAP IN THE HEADLINES
BETWEEN THE NEIGHBORING OFFICES. BASED ON LATEST RADAR
TRENDS...WILL LIKELY BE ABLE TO CANCEL OUR WW ADVISORY BEFORE THE 10
PM EXPIRATION.
TEMPERATURES WILL CONTINUE TO HOLD STEADY IN THE UPPER 20S AND LOW
30S THROUGH THE EVE BEFORE GRADUALLY DROPPING OFF INTO THE LOW TO
MID 20S OVERNIGHT.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
SHALLOW BKN-OVC CLOUD COVER...A 5-10 KT NW SFC WIND AND JUST A FEW
MTN FLURRIES WILL LINGER INTO LATE TONIGHT. ALL SNOW SHOULD END BY
MIDNIGHT...WITH GRADUAL CLEARING FROM NW TO SE INTO THE EARLY
MORNING HOURS ON THURS. MIN TEMPS AT DAYBREAK THURSDAY WILL BE IN
THE UPPER TEENS ACROSS THE HIGHER TERRAIN OF THE NORTH AND
WEST...AND LOWER TO MID 20S IN THE CENTRAL AND SE ZONES.
HIGH PRESSURE SLIDES INTO THE REGION FROM THE MID MS VLY.
INCREASING WESTERLY FLOW AND WARMING ALOFT WILL ALLOW TEMPS TO
REBOUND BACK TO ABOVE NORMAL MAXS BY SEVERAL DEG F OR MORE. CLOUD
COVER LOOKS TO BE QUITE MINIMAL UNDER STRONG ANTICYCLONIC LOW-
MID LEVEL FLOW. HIGHS WILL BE IN THE MID 30S ACROSS THE MTNS...AND
UPPER 30S TO LOWER 40S ELSEWHERE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
NEXT COLD FRONT EVEN SLOWER NOW. ADJUSTED FCST SOME FOR THIS.
FIRST PUSH OF COLDER AIR MOVES INTO THE AREA LATE FRIDAY NIGHT.
SECOND PUSH OF COLD AIR MOVES IN ON SUNDAY.
MODELS TODAY SHOW MORE DIRECTIONAL SHEAR. STILL EXPECT SOME
LAKE EFFECT LATE FRIDAY NIGHT INTO SUNDAY NIGHT WITH THE
COLD AIR ACROSS THE LAKES...BUT THINK INLAND EXTENT WILL
BE LIMITED...AND ALSO AMTS SHOULD NOT BE ALL THAT GREAT...
GIVEN THE ABOVE FACTOR.
IT WILL BE WINDY OVER THE WEEKEND...THUS THERE WILL BE SOME
WIND CHILL WITH THIS AIRMASS...A CHANGE FROM RECENT WEEKS.
DID EDGE TEMPS DOWN SOME THROUGH MONDAY...BUT DID NOT WANT
TO JUMP ON THE COLD AIR TOO HARD. STILL A LOT OF SPREAD
IN MODEL SOLUTIONS.
LEFT THE FCST DRY AFTER SUNDAY NIGHT...A LOT OF MODEL
SPREAD AND ALSO HPC HAS DECENT SW FLOW INTO WED. JUST
HARD TO SEE A REASON TO INTRODUCE RAIN AND SNOW AT THIS
POINT.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
WDSPRD IFR/LIFR CONDS WILL CONTINUE THRU EARLY EVE IN LGT TO MOD
SN WITH VIS BTWN 1/2-2SM. VIS WILL GREATLY IMPROVE AS THE SNOW
ENDS BUT LOW CIGS MAY PERSIST MAINLY OVR THE MTNS. ALL GUIDANCE
RETURNS VFR FLYING INTO EARLY THURS MORNING...WITH GOOD FLYING
PERSISTING THRU THE END OF THE WEEK.
OUTLOOK...
THU-FRI...VFR.
FRI NIGHT-SUN...RESTRICTIONS LKLY.
MON...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ024>026-033>035.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...FITZGERALD/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
353 PM EST WED FEB 8 2012
.SYNOPSIS...
A STRONG UPPER LEVEL SYSTEM CROSSING THE MID-ATLANTIC REGION THIS
AFTERNOON WILL MOVE OFFSHORE LATE TONIGHT INTO EARLY THURSDAY.
HIGH PRESSURE OVER THE MID MISSISSIPPI VALLEY WILL SLIDE EAST TO
THE CAROLINA COAST THROUGH FRIDAY...PROVIDING FAIR AND DRY
WEATHER IN PENNSYLVANIA FOR THE END OF THE WEEK. AN AMPLIFYING
UPPER LEVEL TROUGH OVER THE EASTERN U.S. WILL SEND A STRONG COLD
FRONT SOUTHEAST ACROSS THE STATE FRIDAY NIGHT...ALLOWING MODIFIED
ARCTIC AIR TO POUR INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
AFTN WV LOOP SHOWS THE MID LVL SHORTWAVE RESPONSIBLE FOR THE
LGT SNFL PIVOTING EWD ACRS THE CENTRAL APPALACHIANS. THE BEST
AREA OF ENHANCED LIFT VIA LEFT EXIT REGION UPPER JET DYNAMICS
APPEARS TO BE SHIFTING SEWD TOWARD THE DC AREA PER RECENT RADAR
RETURNS...WITH GENERALLY LIGHTER/FINER DEFORMATION TYPE SNOWS
WRAPPING EWD ACRS WRN AND CNTRL PA. 19Z RUC ANALYSIS SHOWS AN
INVERTED SFC TROUGH EXTENDING NWD ALONG THE ALLEGHENIES FROM A
WEAK 1021MB LOW OVER THE WV PNHDL. MDL QPF/S ARE IN GOOD AGREEMENT
WITH AN ADDITIONAL 0.10-0.25" LIQ EQUIVS INVOF SOUTH MTN AND THE
LWR SUSQ VLY THRU 0000 UTC. ADDITIONAL ACCUMS OF 0.5-1.0 CAN BE
EXPECTED THROUGH THE LATE EVE.
WEBCAMS INDICATE THAT SNOW IS ACCUMULATING MAINLY ON THE GRASSY
SFCS...AS ROAD TEMPERATURES/TIME OF DAY CONTINUE TO BE LIMITING
FACTORS. A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE
LAUREL HIGHLANDS AND S-CENTRAL MTNS WITH STORM TOTALS BETWEEN 2-4
INCHES...WITH THE HIGHEST AMTS ON THE RIDGES WEST OF RT 219. PHL
ISSUED AN IMPACT-BASED ADVISORY /1-2" FOR THE EVE COMMUTE/ AND LWX
HAS LOWER ADVY CRITERIA. THIS EXPLAINS THE GAP IN THE HEADLINES
BETWEEN THE NEIGHBORING OFFICES.
TEMPERATURES WILL CONTINUE TO HOLD STEADY IN THE UPPER 20S AND LOW
30S THROUGH THE EVE BEFORE GRADUALLY DROPPING OFF INTO THE LOW TO
MID 20S OVERNIGHT. SNOWFALL TAPERS OFF FROM WEST TO EAST THIS
EVENING AND EARLY TNT...AS THE MID-UPPER TROUGH /AND MEAGER SFC
WAVE/ SLIDES OFF THE MID ATLANTIC/VA COAST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
SHALLOW BKN-OVC CLOUD COVER...A 5-10 KT NW SFC WIND AND JUST A FEW
MTN FLURRIES WILL LINGER INTO LATE TONIGHT. ALL SNOW SHOULD END BY
MIDNIGHT...WITH GRADUAL CLEARING FROM NW TO SE INTO THE EARLY
MORNING HOURS ON THURS. MIN TEMPS AT DAYBREAK THURSDAY WILL BE IN
THE UPPER TEENS ACROSS THE HIGHER TERRAIN OF THE NORTH AND
WEST...AND LOWER TO MID 20S IN THE CENTRAL AND SE ZONES.
HIGH PRESSURE SLIDES INTO THE REGION FROM THE MID MS VLY.
INCREASING WESTERLY FLOW AND WARMING ALOFT WILL ALLOW TEMPS TO
REBOUND BACK TO ABOVE NORMAL MAXS BY SEVERAL DEG F OR MORE. CLOUD
COVER LOOKS TO BE QUITE MINIMAL UNDER STRONG ANTICYCLONIC LOW-
MID LEVEL FLOW. HIGHS WILL BE IN THE MID 30S ACROSS THE MTNS...AND
UPPER 30S TO LOWER 40S ELSEWHERE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
NEXT COLD FRONT EVEN SLOWER NOW. ADJUSTED FCST SOME FOR THIS.
FIRST PUSH OF COLDER AIR MOVES INTO THE AREA LATE FRIDAY NIGHT.
SECOND PUSH OF COLD AIR MOVES IN ON SUNDAY.
MODELS TODAY SHOW MORE DIRECTIONAL SHEAR. STILL EXPECT SOME
LAKE EFFECT LATE FRIDAY NIGHT INTO SUNDAY NIGHT WITH THE
COLD AIR ACROSS THE LAKES...BUT THINK INLAND EXTENT WILL
BE LIMITED...AND ALSO AMTS SHOULD NOT BE ALL THAT GREAT...
GIVEN THE ABOVE FACTOR.
IT WILL BE WINDY OVER THE WEEKEND...THUS THERE WILL BE SOME
WIND CHILL WITH THIS AIRMASS...A CHANGE FROM RECENT WEEKS.
DID EDGE TEMPS DOWN SOME THROUGH MONDAY...BUT DID NOT WANT
TO JUMP ON THE COLD AIR TOO HARD. STILL A LOT OF SPREAD
IN MODEL SOLUTIONS.
LEFT THE FCST DRY AFTER SUNDAY NIGHT...A LOT OF MODEL
SPREAD AND ALSO HPC HAS DECENT SW FLOW INTO WED. JUST
HARD TO SEE A REASON TO INTRODUCE RAIN AND SNOW AT THIS
POINT.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
WDSPRD IFR/LIFR CONDS WILL CONTINUE THRU EARLY EVE IN LGT TO MOD
SN WITH VIS BTWN 1/2-2SM. VIS WILL GREATLY IMPROVE AS THE SNOW
ENDS BUT LOW CIGS MAY PERSIST MAINLY OVR THE MTNS. ALL GUIDANCE
RETURNS VFR FLYING INTO EARLY THURS MORNING...WITH GOOD FLYING
PERSISTING THRU THE END OF THE WEEK.
OUTLOOK...
THU-FRI...VFR.
FRI NIGHT-SUN...RESTRICTIONS LKLY.
MON...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ024>026-033>035.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
304 PM EST WED FEB 8 2012
.SYNOPSIS...
A STRONG UPPER LEVEL SYSTEM CROSSING THE MID-ATLANTIC REGION THIS
AFTERNOON WILL MOVE OFFSHORE LATE TONIGHT INTO EARLY THURSDAY.
HIGH PRESSURE OVER THE MID MISSISSIPPI VALLEY WILL SLIDE EAST TO
THE CAROLINA COAST THROUGH FRIDAY...PROVIDING FAIR AND DRY
WEATHER IN PENNSYLVANIA FOR THE END OF THE WEEK. AN AMPLIFYING
UPPER LEVEL TROUGH OVER THE EASTERN U.S. WILL SEND A STRONG COLD
FRONT SOUTHEAST ACROSS THE STATE FRIDAY NIGHT...ALLOWING MODIFIED
ARCTIC AIR TO POUR INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
AFTN WV LOOP SHOWS THE MID LVL SHORTWAVE RESPONSIBLE FOR THE
LGT SNFL PIVOTING EWD ACRS THE CENTRAL APPALACHIANS. THE BEST
AREA OF ENHANCED LIFT VIA LEFT EXIT REGION UPPER JET DYNAMICS
APPEARS TO BE SHIFTING SEWD TOWARD THE DC AREA PER RECENT RADAR
RETURNS...WITH GENERALLY LIGHTER/FINER DEFORMATION TYPE SNOWS
WRAPPING EWD ACRS WRN AND CNTRL PA. 19Z RUC ANALYSIS SHOWS AN
INVERTED SFC TROUGH EXTENDING NWD ALONG THE ALLEGHENIES FROM A
WEAK 1021MB LOW OVER THE WV PNHDL. MDL QPF/S ARE IN GOOD AGREEMENT
WITH AN ADDITIONAL 0.10-0.25" LIQ EQUIVS INVOF SOUTH MTN AND THE
LWR SUSQ VLY THRU 0000 UTC. ADDITIONAL ACCUMS OF 0.5-1.0 CAN BE
EXPECTED THROUGH THE LATE EVE.
WEBCAMS INDICATE THAT SNOW IS ACCUMULATING MAINLY ON THE GRASSY
SFCS...AS ROAD TEMPERATURES/TIME OF DAY CONTINUE TO BE LIMITING
FACTORS. A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR THE
LAUREL HIGHLANDS AND S-CENTRAL MTNS WITH STORM TOTALS BETWEEN 2-4
INCHES...WITH THE HIGHEST AMTS ON THE RIDGES WEST OF RT 219. PHL
ISSUED AN IMPACT-BASED ADVISORY /1-2" FOR THE EVE COMMUTE/ AND LWX
HAS LOWER ADVY CRITERIA. THIS EXPLAINS THE GAP IN THE HEADLINES
BETWEEN THE NEIGHBORING OFFICES.
TEMPERATURES WILL CONTINUE TO HOLD STEADY IN THE UPPER 20S AND LOW
30S THROUGH THE EVE BEFORE GRADUALLY DROPPING OFF INTO THE LOW TO
MID 20S OVERNIGHT. SNOWFALL TAPERS OFF FROM WEST TO EAST THIS
EVENING AND EARLY TNT...AS THE MID-UPPER TROUGH /AND MEAGER SFC
WAVE/ SLIDES OFF THE MID ATLANTIC/VA COAST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 AM THURSDAY/...
SHALLOW BKN-OVC CLOUD COVER...A 5-10 KT NW SFC WIND AND JUST A FEW
MTN FLURRIES WILL LINGER INTO LATE TONIGHT. ALL SNOW SHOULD END BY
MIDNIGHT...WITH GRADUAL CLEARING FROM NW TO SE INTO THE EARLY
MORNING HOURS ON THURS. MIN TEMPS AT DAYBREAK THURSDAY WILL BE IN
THE UPPER TEENS ACROSS THE HIGHER TERRAIN OF THE NORTH AND
WEST...AND LOWER TO MID 20S IN THE CENTRAL AND SE ZONES.
HIGH PRESSURE SLIDES INTO THE REGION FROM THE MID MS VLY.
INCREASING WESTERLY FLOW AND WARMING ALOFT WILL ALLOW TEMPS TO
REBOUND BACK TO ABOVE NORMAL MAXS BY SEVERAL DEG F OR MORE. CLOUD
COVER LOOKS TO BE QUITE MINIMAL UNDER STRONG ANTICYCLONIC LOW-
MID LEVEL FLOW. HIGHS WILL BE IN THE MID 30S ACROSS THE MTNS...AND
UPPER 30S TO LOWER 40S ELSEWHERE.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
FRIDAY MORNING WILL START OUR CLEAR TO PARTLY CLOUDY ACROSS THE
EAST...WHILE A SHIELD OF LAYERED CLOUDS QUICKLY OVERSPREADS THE WEST
IN THE MODERATELY STRONG WARM ADVECTION PATTERN AHEAD OF AN ARCTIC
FRONT.
THIS FRONT WILL CROSS THE REGION FRIDAY NIGHT...BRINGING WITH IT
NUMEROUS SNOW SHOWERS AND POSSIBLE SQUALLS ACROSS THE WESTERN AND
NRN HIGH TERRAIN...WITH SCATTERED SNOW SHOWERS AND PERHAPS A BRIEF
SQUALL OVER THE CENTRAL AND EASTERN PARTS OF THE STATE.
TEMPS FRIDAY MAY BE A FEW DEG LOWER THAN THURSDAY ACROSS THE WESTERN
ZONES...WHILE THE EXTENT OF MORNING SUNSHINE IN THE CENTRAL AND EAST
/COMBINED WITH THE INCREASING AND WARMING DOWNSLOPE WESTERLY FLOW/
WILL ALLOW TEMPS TO WARM BY ANOTHER FEW DEG F...TOPPING OUT 4-7 DEG
F ABOVE NORMAL..
THE CORE OF THE REAL COLD AIR WILL STAY WELL TO THE NORTH OF LAKES
ERIE/ONTARIO...AND OVER EASTERN CANADA...WHERE THERE IS DECENT SNOW
COVER.
INCREASING LLVL...DIRECTIONAL SHEAR FROM THE WEST-NW WILL COMBINE
WITH RELATIVELY LOW SUBSIDENCE INVERSION HEIGHTS TO KEEP ANY MTN
SNOW SHOWERS ON THE MINIMAL SIDE SATURDAY INTO SUNDAY.
THE HIGH PRESSURE AREA WILL SETTLE TO THE SOUTH OF PENNSYLVANIA
EARLY NEXT WEEK...ALLOWING FOR A QUICK WARMUP AND DRY WEATHER MONDAY
AND TUESDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
WDSPRD IFR/LIFR CONDS WILL CONTINUE THRU EARLY EVE IN LGT TO MOD
SN WITH VIS BTWN 1/2-2SM. VIS WILL GREATLY IMPROVE AS THE SNOW
ENDS BUT LOW CIGS MAY PERSIST MAINLY OVR THE MTNS. ALL GUIDANCE
RETURNS VFR FLYING INTO EARLY THURS MORNING...WITH GOOD FLYING
PERSISTING THRU THE END OF THE WEEK.
OUTLOOK...
THU-FRI...VFR.
FRI NIGHT-SUN...RESTRICTIONS LKLY.
MON...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ024>026-033>035.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...LAMBERT/MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
513 PM MST THU FEB 9 2012
.DISCUSSION...A LARGE HUDSON BAY LOW WILL DOMINATE OUR WEATHER
THROUGH MUCH OF THE WEEKEND. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE...WITH A SUBSTANTIAL LOW-LEVEL TEMPERATURE GRADIENT ACROSS THE
CWA. THE COLD AIR AND BAROCLINIC ZONE WILL HELP TO SQUEEZE OUT THE
LIMITED MOISTURE...WITH SOME SPOTS IN NERN WY SEEING A FEW INCHES OF
ACCUMULATION.
UPPER JETS KISS OVER CWA TONIGHT AND INTENSIFY SLIGHTLY. THIS IS
FOLLOWED BY AN INFLUX OF COLDER AIR AND EVENTUALLY AN UPPER-LEVEL
TROUGH PASSAGE FRIDAY NIGHT AND SATURDAY MORNING. A STRONG...COLD
SURFACE HIGH PRESSURE ALSO WILL MOVE SOUTH ACROSS THE DAKOTAS ON
SATURDAY...BEHIND THE UPPER WAVE. AFTER THAT THE FLOW ALOFT BECOMES
WEAK...AND THUS AMENABLE TO SUBSTANTIAL LOW CLOUDS AND POSSIBLY SOME
FOG LATE SATURDAY THROUGH SUNDAY MRNG. LOW FROUDE FLOW THROUGH THE
PERIOD WILL PRECLUDE UPSLOPE SNOWS...BUT LOCAL ENHANCEMENT MAY OCCUR
IN THE NRN FOOTHILLS.
AN INITIAL SHOT OF LIGHT SNOW IS EXPECTED TONIGHT WITH THE LEADING
EDGE OF THE ARCTIC AIR...ESPECIALLY OVER NWRN THROUGH CNTRL SD. EVEN
THOUGH MOST MODELS HAVE NO INDICATION OF QPF...UPSTREAM OBS AND THE
HRRR AND RUC DO SUGGEST LIGHT SNOW SHOWERS MAY EVEN LINGER PAST 06Z
OVER MUCH OF THE SD PLAINS. OTHERWISE...THE BEST FORCING FOR UPWARD
MOTION WILL BE OVER NERN WY AND FAR SWRN SD FRIDAY AND FRIDAY NIGHT
AS TWO MORE JETS INTERACT. FRONTOGENESIS ALSO WILL BE ACTIVE ALONG
THE BAROCLINIC ZONE OVER NERN WY...AND THUS EXPECT A FEW INCHES OF
SNOWFALL. THE BAROCLINIC ZONE WILL BECOME SOMEWHAT DIFFUSE BY EARLY
SUNDAY...BUT IT STILL WILL RESIDE OVER THE SWRN CWA. THIS MAY
PROVIDE AN ADDITIONAL FOCUS FOR SNOW ON SUNDAY AS AN UPPER TROUGH
MOVES OVER THE FOUR CORNERS REGION.
LATEST MOS GUIDANCE HAS TRENDED COLDER WITH LOWS THE NEXT TWO DAYS.
WHILE THE TEMPS HAVE BEEN NUDGED LOWER...HAVE NOT GONE AS COLD AS
MOS...ESPECIALLY WHERE CLOUD COVER IS EXPECTED.
EXTENDED...UPPER LEVEL FLOW REMAINS NORTHWESTERLY OVER THE NORTHERN
PLAINS FOR EARLY NEXT WEEK. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW
POOR AGREEMENT ON TIMING AND PLACEMENT OF SEVERAL WEAK SHORTWAVES
THAT CROSS THE AREA. REGARDLESS...ATMOSPHERE REMAINS FAIRLY DRY WITH
THIS REGIME. WILL CONTINUE WITH A DRY FORECAST. TEMPERATURES IN THIS
TYPE OF FLOW SHOULD REMAIN NEAR AVERAGE.
&&
.AVIATION...00Z TAF FORECASTS
GUSTY NORTHWEST WINDS WILL CONTINUE SUBSIDE THROUGH THIS EVENING.
MVFR CIGS WILL SLIDE SOUTHWARD ACROSS NORTHWESTERN AND CENTRAL SOUTH
DAKOTA THIS EVENING...AND INTO WESTERN SOUTH DAKOTA AFTER 06Z. LIGHT
SNOW IS ALSO EXPECTED TO DEVELOP ACROSS PARTS OF NORTHEASTERN
WYOMING AND FAR WESTERN SOUTH DAKOTA THROUGH EARLY FRIDAY MORNING.
ALONG WITH MVFR CIGS...THE SNOWFALL WILL RESULT IN MVFR VSBY WITH
LOCAL IFR CONDITIONS POSSIBLE.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1028 AM CST WED FEB 8 2012
.UPDATE...
RELATIVELY QUIET WEATHER ON TAP FOR SOUTHEAST TEXAS TODAY WITH
SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTH. SKIES WILL
REMAIN PARTLY CLOUDY AS SOUTHWESTERLY FLOW ALOFT BRINGS HIGH
CLOUDS ACROSS THE REGION. CURRENT FORECAST IS IN GOOD SHAPE AND NO
CHANGES PLANNED FOR THIS MORNING. 38
&&
.MARINE...
WINDS OVER THE FAR OFFSHORE WATER RUNNING AROUND 20 KNOTS AND SEAS
OF 6 TO 7 FEET SHOULD BE VERY SLOW TO COME DOWN WITH THE NE FETCH.
SCA WILL COME DOWN THERE AT 3 PM BUT SCEC WILL LIKELY CONTINUE AFTER
THROUGH AT LEAST MID EVENING AND MAY GO PAST MIDNIGHT.
45
&&
.AVIATION...
BACK TO VFR. HIGH CLOUDS AND NORTH WINDS 5-13KTS DIMINISHING
OVERNIGHT.
45
&&
.PREV DISCUSSION... /ISSUED 417 AM CST WED FEB 8 2012/
DISCUSSION...
A WEAK NORTHERN BOUNDARY SLIPPING ACROSS THE AREA EARLY THIS
MORNING...ONLY NOTICEABLE IN THE INCREASED PRESSURE FIELD AND
IN THE REINFORCING OF THE ANCHORED COOL AND DRY AIR MASS. A DAY
OF SCATTERED MID TO HIGH CLOUD COVER WITH THIS SLIGHTLY COOLER
NORTHERLY AIR MASS ONLY NOTICEABLE IN THE MAXIMUM TEMPERATURE
NUMBERS...A FEW DEGREES COOLER THAN YESTERDAY.
THE SYNOPTIC SCENARIO OF A MID TO LATE WEEK WEST COAST UPPER LOW
CUTTING OFF AND SETTLING IN OVER BAJA IS STILL ON TRACK...WITH
INCREASING PRECIPITATION CHANCES FROM LATE THURSDAY ON INTO THE
WEEKEND. CHANCE PROBABILITIES APPEAR TO BE ON THE RISE FRIDAY
INTO SATURDAY BECAUSE OF A FEW FACTORS. FIRST WOULD BE A SERIES OF
SHORTWAVE DISTURBANCES WITHIN THE SOUTHWEST-TO-NORTHEAST FLOW
RIDING UP THE COAST AND PROVIDING ENOUGH INSTABILITY...IN TANDEM
WITH DECENT ISENTROPIC UPLIFT...TO PRODUCE MAINLY LIGHT RAIN AND
ELEVATED THUNDER. ANOTHER POSITIVE WILL BE THE POSITIONING OF THE
SOUTHERN BRANCH OF THE POLAR JET STREAM...WITH COASTAL TEXAS
FALLING UNDER THE LF QUADRANT EARLY FRIDAY THEN TRANSITIONING TO
BEING UNDER THE RR QUAD LATTER IN THE DAY. THUS...WARM AIR
ADVECTION-TYPE LIGHT RAIN (LOW QPF) AS LOWER LEVEL DRY AIR (PER
ENTRENCHED LL (NORTH)EASTERLY FLOW) SHOULD COUNTERACT ANY
SIGNIFICANT ACCUMULATION/WIDESPREAD MODERATE RAIN COVERAGE.
SHALLOW UPPER LEVEL TROUGH AXIS WILL MOVE TO THE EAST OF TEXAS BY
SATURDAY AFTERNOON WITH ANOTHER WESTERN TROUGH EVOLVING OVER THE
ROCKIES SUNDAY INTO MONDAY. LEE SURFACE PRESSURES BEGIN TO LOWER
ACROSS WESTERN TEXAS EARLY MONDAY...ALLOWING MID-LOW WINDS TO TURN
AROUND TO ONSHORE AND BEGIN AN EARLY WEEK MOISTURE PUMP. INCREASING
HUMIDITIES AND RAIN CHANCES AS THE AREA FALLS JUST DOWNSTREAM OF A
DEVELOPING TEXAS PANHANDLE COLD FRONT. A PRIMARILY WEAK 5H TROUGH
PASSAGE MONDAY IS MODELED TO BE FOLLOWED BY A MUCH STRONGER STORM
SYSTEM TIMED TO AFFECT THE REGION A WEEK FROM NOW. THUS...MODEST
RAIN CHANCES FROM MONDAY`S WEAKER SYSTEM ARE FORECAST TO PICK UP
AGAIN WEDNESDAY. THE MAIN COLD FRONT IS TIMED TO PASS ACROSS TEXAS
WEDNESDAY BUT...IN THE DAYS LEADING UP TO THIS FROPA...EXPECT A COUPLE
OF WARM (LOWER 70 MAX TEMPS/LOWS IN THE 50S) AND MORE HUMID COUPLE
OF DAYS UNDER MAINLY OVERCAST SKIES AND HIGHER RAIN CHANCES. 31
MARINE...
PRES GRADIENT TIGHTENING OFFSHORE AND BELIEVE CURRENT FLAG CONFIGURATION
LOOKS GOOD (CAUTION BAYS & NEARSHORE, ADVISORY OFFSHORE) THROUGH
THIS AFTERNOON. WINDS WILL DIMINISH A BIT AND BECOME MORE NE LATE
IN THE DAY AND TONIGHT...BUT REMAIN AROUND 15 KT OFFSHORE FOR SEVERAL
DAYS. ANOTHER FRONT WILL DROP INTO THE PLAINS AND ERN U.S. THIS
WEEKEND WHICH WILL AGAIN TIGHTEN THE GRADIENT ALONG THE UPPER TX
COASTAL WATERS. CORRESPONDING WINDS & SEAS WILL INCREASE. TIDE
LEVELS WILL PROBABLY RUN 1-1.5 FEET ABOVE NORMAL THIS WEEKEND INTO
EARLY NEXT WEEK WITH A DECENT FETCH OF ENE WINDS IN PLACE. 47
AVIATION...
VFR. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 61 41 64 46 63 / 10 10 20 30 30
HOUSTON (IAH) 64 42 65 45 65 / 10 10 20 20 30
GALVESTON (GLS) 62 50 62 51 64 / 10 10 20 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 PM CST THIS
AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...
MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT
20 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...38
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
417 AM CST WED FEB 8 2012
.DISCUSSION...
A WEAK NORTHERN BOUNDARY SLIPPING ACROSS THE AREA EARLY THIS
MORNING...ONLY NOTICEABLE IN THE INCREASED PRESSURE FIELD AND
IN THE REINFORCING OF THE ANCHORED COOL AND DRY AIR MASS. A DAY
OF SCATTERED MID TO HIGH CLOUD COVER WITH THIS SLIGHTLY COOLER
NORTHERLY AIR MASS ONLY NOTICEABLE IN THE MAXIMUM TEMPERATURE
NUMBERS...A FEW DEGREES COOLER THAN YESTERDAY.
THE SYNOPTIC SCENARIO OF A MID TO LATE WEEK WEST COAST UPPER LOW
CUTTING OFF AND SETTLING IN OVER BAJA IS STILL ON TRACK...WITH
INCREASING PRECIPITATION CHANCES FROM LATE THURSDAY ON INTO THE
WEEKEND. CHANCE PROBABILITIES APPEAR TO BE ON THE RISE FRIDAY
INTO SATURDAY BECAUSE OF A FEW FACTORS. FIRST WOULD BE A SERIES OF
SHORTWAVE DISTURBANCES WITHIN THE SOUTHWEST-TO-NORTHEAST FLOW
RIDING UP THE COAST AND PROVIDING ENOUGH INSTABILITY...IN TANDEM
WITH DECENT ISENTROPIC UPLIFT...TO PRODUCE MAINLY LIGHT RAIN AND
ELEVATED THUNDER. ANOTHER POSITIVE WILL BE THE POSITIONING OF THE
SOUTHERN BRANCH OF THE POLAR JET STREAM...WITH COASTAL TEXAS
FALLING UNDER THE LF QUADRANT EARLY FRIDAY THEN TRANSITIONING TO
BEING UNDER THE RR QUAD LATTER IN THE DAY. THUS...WARM AIR
ADVECTION-TYPE LIGHT RAIN (LOW QPF) AS LOWER LEVEL DRY AIR (PER
ENTRENCHED LL (NORTH)EASTERLY FLOW) SHOULD COUNTERACT ANY
SIGNIFICANT ACCUMULATION/WIDESPREAD MODERATE RAIN COVERAGE.
SHALLOW UPPER LEVEL TROUGH AXIS WILL MOVE TO THE EAST OF TEXAS BY
SATURDAY AFTERNOON WITH ANOTHER WESTERN TROUGH EVOLVING OVER THE
ROCKIES SUNDAY INTO MONDAY. LEE SURFACE PRESSURES BEGIN TO LOWER
ACROSS WESTERN TEXAS EARLY MONDAY...ALLOWING MID-LOW WINDS TO TURN
AROUND TO ONSHORE AND BEGIN AN EARLY WEEK MOISTURE PUMP. INCREASING
HUMIDITIES AND RAIN CHANCES AS THE AREA FALLS JUST DOWNSTREAM OF A
DEVELOPING TEXAS PANHANDLE COLD FRONT. A PRIMARILY WEAK 5H TROUGH
PASSAGE MONDAY IS MODELED TO BE FOLLOWED BY A MUCH STRONGER STORM
SYSTEM TIMED TO AFFECT THE REGION A WEEK FROM NOW. THUS...MODEST
RAIN CHANCES FROM MONDAY`S WEAKER SYSTEM ARE FORECAST TO PICK UP
AGAIN WEDNESDAY. THE MAIN COLD FRONT IS TIMED TO PASS ACROSS TEXAS
WEDNESDAY BUT...IN THE DAYS LEADING UP TO THIS FROPA...EXPECT A COUPLE
OF WARM (LOWER 70 MAX TEMPS/LOWS IN THE 50S) AND MORE HUMID COUPLE
OF DAYS UNDER MAINLY OVERCAST SKIES AND HIGHER RAIN CHANCES. 31
&&
.MARINE...
PRES GRADIENT TIGHTENING OFFSHORE AND BELIEVE CURRENT FLAG CONFIGURATION
LOOKS GOOD (CAUTION BAYS & NEARSHORE, ADVISORY OFFSHORE) THROUGH
THIS AFTERNOON. WINDS WILL DIMINISH A BIT AND BECOME MORE NE LATE
IN THE DAY AND TONIGHT...BUT REMAIN AROUND 15 KT OFFSHORE FOR SEVERAL
DAYS. ANOTHER FRONT WILL DROP INTO THE PLAINS AND ERN U.S. THIS
WEEKEND WHICH WILL AGAIN TIGHTEN THE GRADIENT ALONG THE UPPER TX
COASTAL WATERS. CORRESPONDING WINDS & SEAS WILL INCREASE. TIDE
LEVELS WILL PROBABLY RUN 1-1.5 FEET ABOVE NORMAL THIS WEEKEND INTO
EARLY NEXT WEEK WITH A DECENT FETCH OF ENE WINDS IN PLACE. 47
&&
.AVIATION...
VFR. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 61 41 64 46 63 / 10 10 20 30 30
HOUSTON (IAH) 64 42 65 45 65 / 10 10 20 20 30
GALVESTON (GLS) 62 50 62 51 64 / 10 10 20 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 PM CST THIS
AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...
MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT
20 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1146 PM CST TUE FEB 7 2012
.DISCUSSION...
SEE AVIATION SECTION.
&&
.AVIATION...
PER TRENDS IN SATELLITE IMAGERY...A NEW LOW CLOUD FIELD /WITH MVFR
CEILINGS/ HAS PUSHED SOUTH ACROSS THE BIG COUNTRY. THE LATEST RUC
DATA INDICATES THAT THESE LOW CLOUDS WILL ADVANCE SOUTH TO NEAR
INTERSTATE 10 OVERNIGHT...AND PERSIST INTO THE MID-MORNING HOURS.
HAVE INITIALIZED THE KABI TAF WITH A BROKEN CEILING OF 2K FT. WILL
LEAN TOWARD THE RUC WITH THE DEVELOPMENT OF LOW CLOUDS AT THE TAF
SITES FARTHER SOUTH OVERNIGHT. SOME UNCERTAINTY IN HOW LONG THESE
LOW CLOUDS WILL PERSIST INTO WEDNESDAY MORNING...AND NONE OF THE
MODEL DATA HAS HANDLED THE LOW CLOUD FIELDS THAT WELL BEYOND
SEVERAL HOURS. CARRYING A SCATTERED VFR CLOUD GROUP AT ALL SITES
WEDNESDAY AFTERNOON AND EVENING. PER MODEL INDICATIONS...LOW CLOUDS
SHOULD BEGIN TO DEVELOP NORTH INTO OUR SOUTHERN COUNTIES BETWEEN 03Z
AND 06Z THURSDAY. NORTH WINDS OVERNIGHT AND WEDNESDAY MORNING WILL
VEER TO THE EAST WEDNESDAY AFTERNOON...AND TO THE SOUTHEAST WEDNESDAY
NIGHT.
19
&&
.PREV DISCUSSION... /ISSUED 1111 PM CST TUE FEB 7 2012/
UPDATE...
LATEST SATELLITE DATA INDICATE SKIES ARE CLEAR ACROSS MOST OF WEST
CENTRAL TEXAS...WHILE LOW CLOUDS ARE SPREADING INTO THE BIG
COUNTRY FROM THE NORTH. LATEST RUC AND NAM DATA INDICATE THE LOW
CLOUDS WILL CONTINUE TO PUSH SOUTH ACROSS WEST CENTRAL TEXAS FOR
THE REMAINDER OF TONIGHT. THUS...I HAVE INCREASED SKY GRIDS TO 100
PERCENT BY 12Z FOR ALL BUT OUR SOUTHERN COUNTIES. PLUS...WITH THE
INCREASING CLOUD COVER...I INCREASED OVERNIGHT LOWS A DEGREE OR
TWO FOR TONIGHT OVER SOME OF OUR NORTHERN COUNTIES. LATEST ZONE
PRODUCT REFLECTS THESE CHANGES.
HUBER
PREV DISCUSSION... /ISSUED 559 PM CST TUE FEB 7 2012/
DISCUSSION...
SEE AVIATION SECTION.
AVIATION...
VFR CONDITIONS...FOR THE MOST PART...WILL PREVAIL THROUGH THE NEXT 24
HOURS.THE POSSIBLE EXCEPTION IS AT KBBD AND KJCT BETWEEN 09Z AND
16Z WEDNESDAY. AREA OF CLOUDS WITH CEILINGS 4K-5K FT WILL OVERSPREAD
THE SOUTHERN PART OF WEST CENTRAL TEXAS THROUGH EARLY TONIGHT.
THIS TAF PACKAGE...BASED PARTLY ON GUIDANCE FROM THE 18Z NAM RH
AT 800MB...HAS CLOUD CEILINGS PERSISTING WELL INTO THE NIGHT AT
KSJT...KBBD AND KJCT. HOWEVER...WILL MONITOR SATELLITE TRENDS AND
MAY NEED TO AMEND WITH A LONGER PERIOD OF CLEARING AT THESE
SITES. OVERNIGHT...BOUNDARY LAYER MOISTURE FIELDS SUGGEST A LOW
CLOUD FIELD /WITH MVFR CEILINGS/ DEVELOPING ACROSS OUR EASTERN
COUNTIES. CARRYING A 2K-3K CEILING AT KBBD AND KJCT ROUGHLY
BETWEEN 09Z AND 16Z. ANTICIPATE THAT THE REST OF OUR AREA WILL
HAVE CLEAR TO PARTLY CLOUDY SKY CONDITION WEDNESDAY MORNING. IN
THE WAKE OF THE RECENT COLD FRONTAL PASSAGE... NORTH WINDS AT
10-15 KT WILL OCCUR THROUGH MUCH OF TONIGHT...WITH A FEW GUSTS TO
20 KT POSSIBLE THROUGH LATE EVENING. NORTH WINDS WILL VEER TO
NORTHEAST BY MIDDAY WEDNESDAY WITH A GRADUAL DECREASE IN SPEEDS.
19
PREV DISCUSSION... /ISSUED 325 PM CST TUE FEB 7 2012/
SHORT TERM...
COLD FRONT PROGRESSING SOUTHWARD ACROSS WEST CENTRAL TEXAS LATE THIS
AFTERNOON. LIFT WITH THE FRONT HAS HELPED EXPAND AN AREA OF LOW AND
MID CLOUDS ACROSS THE BIG COUNTRY. MODELS NOT DOING A GREAT JOB WITH
THESE CLOUDS...ALTHOUGH THE RUC HAS PICKED UP ON THEM TO SOME
DEGREE. SUSPECT THESE CLOUDS WILL EXPAND SOUTH AND COVER MUCH OF
WEST CENTRAL TEXAS BY EVENING...BEFORE STARTING TO DECREASE.
DESPITE THE CLOUD COVER...STILL LOOKS TO BE A COLD NIGHT.
TEMPERATURES ACROSS THE PANHANDLE REMAIN IN THE LOW TO MID 30S THIS
AFTERNOON...SO AIR MASS IS CERTAINLY COLD. GUIDANCE NUMBERS ARE
PRETTY SIMILAR IN THE UPPER 20S AND LOWER 30S...AND NOT GOING TO
DEVIATE TOO MUCH. COLDEST READINGS WILL BE ACROSS THE NORTHERN AND
WESTERN BIG COUNTRY...WHERE AT LEAST SOME BREAKS IN THE CLOUDS WILL
DEVELOP.
COOL AGAIN ON WEDNESDAY...AS COLD ADVECTION CONTINUES. SURFACE HIGH
SLIDES OFF TO THE EAST INTO THE MISSISSIPPI VALLEY...SO WINDS WILL
BEGIN TO SWING AROUND TO THE EAST AND SOUTHEAST BY AFTERNOON.
07
LONG TERM...
AN UPPER LEVEL LOW WILL DEVELOP AT THE BASE OF THE UPPER LEVEL
TROUGH CURRENTLY OVER CALIFORNIA...THEN DIVE SOUTH TO SOUTHERN BAJA
CALIFORNIA BY THURSDAY MORNING. THIS WILL PUT WEST CENTRAL TEXAS IN
SOUTHWEST FLOW A LOT WITH INCREASING PACIFIC MOISTURE AND OCCASIONAL
DISTURBANCES TREKKING ACROSS THE REGION. AS THE PACIFIC MOISTURE
BEGINS TO INCREASE...CLOUD COVER WILL ALSO BE ON THE INCREASE.
EXPECT LOW TO MID LEVEL CLOUDS TO QUICKLY INCREASE BY EARLY THURSDAY
MORNING...WHICH SHOULD SERVE TO KEEP TEMPERATURES UP A
BIT...ESPECIALLY OVER THE SOUTHERN HALF OF THE AREA. LOW
TEMPERATURES ON THURSDAY MORNING WILL RANGE FROM THE LOWER 40S
SOUTH...TO NEAR 30 NORTH. A COOL/DREARY PATTERN WILL SETUP FOR
THURSDAY AND FRIDAY...WITH THE MAIN QUESTIONS BEING RAIN
CHANCES...AND QPF AMOUNTS. ECMWF AND GFS SOLUTIONS BEING TO DIVERGE
BEYOND THURSDAY AS THE GFS IS FASTER IN EJECTING THE LOW INTO NORTH
CENTRAL MEXICO...THEN TRACKING IT ACROSS TEXAS AS A WEAK OPEN WAVE.
THE ECMWF CONTINUES TO BE MUCH SLOWER...HANGING THE LOW OFF THE
PACIFIC COAST THROUGH SATURDAY. THE BEST DYNAMICS WITH THIS LOW WILL
REMAIN WELL SOUTH OF WEST CENTRAL TEXAS...AND HAVE TRIMMED POPS BACK
SLIGHTLY...THURSDAY AND FRIDAY. WOULD NOT BE SURPRISED TO SEE A FEW
SHOWERS AS OCCASIONAL DISTURBANCES EMBEDDED IN THE SOUTHWEST FLOW
ALOFT MOVE OVER THE AREA. DO NOT EXPECT MUCH QPF...AS ANY SHOWERS
THAT DO DEVELOP LOOK TO BE LIGHT AS THIS TIME. IN
ADDITION...DIFFERENCES ARISE IN THE HANDLING OF THE NEXT UPPER LEVEL
TROUGH MOVING ACROSS THE PLAINS ON FRIDAY. THE ECMWF IS DEEPER THAN
THE GFS WITH THE TROUGH...HENCE MORE AGGRESSIVE WITH THE
FRONT...PUSHING IT THROUGH THE AREA ON FRIDAY. AS THE FRONT MOVES
THROUGH...THE ECMWF DEVELOPS SHOWERS ALONG THE BOUNDARY ON FRIDAY.
FOR NOW...HAVE LEFT FRIDAY DRY...BUT FUTURE SHIFTS WILL NEED TO
MONITOR. THE NEXT ISSUE IS THE NEXT UPPER LEVEL TROUGH THAT IS
FORECAST TO SWING ACROSS THE PLAINS SUNDAY INTO MONDAY. MODELS HAVE
BEEN FAIRLY CONSISTENT IN SHOWING INCREASING RAIN CHANCES AHEAD OF
THIS TROUGH...AND HAVE ADDED IN SLIGHT CHANCE POPS SUNDAY AND SUNDAY
NIGHT.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 28 47 32 56 37 / 0 10 10 10 20
SAN ANGELO 33 52 36 54 38 / 0 10 10 10 20
JUNCTION 36 56 39 56 39 / 10 10 10 20 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1111 PM CST TUE FEB 7 2012
.UPDATE...
LATEST SATELLITE DATA INDICATE SKIES ARE CLEAR ACROSS MOST OF WEST
CENTRAL TEXAS...WHILE LOW CLOUDS ARE SPREADING INTO THE BIG
COUNTRY FROM THE NORTH. LATEST RUC AND NAM DATA INDICATE THE LOW
CLOUDS WILL CONTINUE TO PUSH SOUTH ACROSS WEST CENTRAL TEXAS FOR
THE REMAINDER OF TONIGHT. THUS...I HAVE INCREASED SKY GRIDS TO 100
PERCENT BY 12Z FOR ALL BUT OUR SOUTHERN COUNTIES. PLUS...WITH THE
INCREASING CLOUD COVER...I INCREASED OVERNIGHT LOWS A DEGREE OR
TWO FOR TONIGHT OVER SOME OF OUR NORTHERN COUNTIES. LATEST ZONE
PRODUCT REFLECTS THESE CHANGES.
HUBER
&&
.PREV DISCUSSION... /ISSUED 559 PM CST TUE FEB 7 2012/
DISCUSSION...
SEE AVIATION SECTION.
AVIATION...
VFR CONDITIONS...FOR THE MOST PART...WILL PREVAIL THROUGH THE NEXT 24
HOURS.THE POSSIBLE EXCEPTION IS AT KBBD AND KJCT BETWEEN 09Z AND
16Z WEDNESDAY. AREA OF CLOUDS WITH CEILINGS 4K-5K FT WILL OVERSPREAD
THE SOUTHERN PART OF WEST CENTRAL TEXAS THROUGH EARLY TONIGHT.
THIS TAF PACKAGE...BASED PARTLY ON GUIDANCE FROM THE 18Z NAM RH
AT 800MB...HAS CLOUD CEILINGS PERSISTING WELL INTO THE NIGHT AT
KSJT...KBBD AND KJCT. HOWEVER...WILL MONITOR SATELLITE TRENDS AND
MAY NEED TO AMEND WITH A LONGER PERIOD OF CLEARING AT THESE
SITES. OVERNIGHT...BOUNDARY LAYER MOISTURE FIELDS SUGGEST A LOW
CLOUD FIELD /WITH MVFR CEILINGS/ DEVELOPING ACROSS OUR EASTERN
COUNTIES. CARRYING A 2K-3K CEILING AT KBBD AND KJCT ROUGHLY
BETWEEN 09Z AND 16Z. ANTICIPATE THAT THE REST OF OUR AREA WILL
HAVE CLEAR TO PARTLY CLOUDY SKY CONDITION WEDNESDAY MORNING. IN
THE WAKE OF THE RECENT COLD FRONTAL PASSAGE... NORTH WINDS AT
10-15 KT WILL OCCUR THROUGH MUCH OF TONIGHT...WITH A FEW GUSTS TO
20 KT POSSIBLE THROUGH LATE EVENING. NORTH WINDS WILL VEER TO
NORTHEAST BY MIDDAY WEDNESDAY WITH A GRADUAL DECREASE IN SPEEDS.
19
PREV DISCUSSION... /ISSUED 325 PM CST TUE FEB 7 2012/
SHORT TERM...
COLD FRONT PROGRESSING SOUTHWARD ACROSS WEST CENTRAL TEXAS LATE THIS
AFTERNOON. LIFT WITH THE FRONT HAS HELPED EXPAND AN AREA OF LOW AND
MID CLOUDS ACROSS THE BIG COUNTRY. MODELS NOT DOING A GREAT JOB WITH
THESE CLOUDS...ALTHOUGH THE RUC HAS PICKED UP ON THEM TO SOME
DEGREE. SUSPECT THESE CLOUDS WILL EXPAND SOUTH AND COVER MUCH OF
WEST CENTRAL TEXAS BY EVENING...BEFORE STARTING TO DECREASE.
DESPITE THE CLOUD COVER...STILL LOOKS TO BE A COLD NIGHT.
TEMPERATURES ACROSS THE PANHANDLE REMAIN IN THE LOW TO MID 30S THIS
AFTERNOON...SO AIR MASS IS CERTAINLY COLD. GUIDANCE NUMBERS ARE
PRETTY SIMILAR IN THE UPPER 20S AND LOWER 30S...AND NOT GOING TO
DEVIATE TOO MUCH. COLDEST READINGS WILL BE ACROSS THE NORTHERN AND
WESTERN BIG COUNTRY...WHERE AT LEAST SOME BREAKS IN THE CLOUDS WILL
DEVELOP.
COOL AGAIN ON WEDNESDAY...AS COLD ADVECTION CONTINUES. SURFACE HIGH
SLIDES OFF TO THE EAST INTO THE MISSISSIPPI VALLEY...SO WINDS WILL
BEGIN TO SWING AROUND TO THE EAST AND SOUTHEAST BY AFTERNOON.
07
LONG TERM...
AN UPPER LEVEL LOW WILL DEVELOP AT THE BASE OF THE UPPER LEVEL
TROUGH CURRENTLY OVER CALIFORNIA...THEN DIVE SOUTH TO SOUTHERN BAJA
CALIFORNIA BY THURSDAY MORNING. THIS WILL PUT WEST CENTRAL TEXAS IN
SOUTHWEST FLOW A LOT WITH INCREASING PACIFIC MOISTURE AND OCCASIONAL
DISTURBANCES TREKKING ACROSS THE REGION. AS THE PACIFIC MOISTURE
BEGINS TO INCREASE...CLOUD COVER WILL ALSO BE ON THE INCREASE.
EXPECT LOW TO MID LEVEL CLOUDS TO QUICKLY INCREASE BY EARLY THURSDAY
MORNING...WHICH SHOULD SERVE TO KEEP TEMPERATURES UP A
BIT...ESPECIALLY OVER THE SOUTHERN HALF OF THE AREA. LOW
TEMPERATURES ON THURSDAY MORNING WILL RANGE FROM THE LOWER 40S
SOUTH...TO NEAR 30 NORTH. A COOL/DREARY PATTERN WILL SETUP FOR
THURSDAY AND FRIDAY...WITH THE MAIN QUESTIONS BEING RAIN
CHANCES...AND QPF AMOUNTS. ECMWF AND GFS SOLUTIONS BEING TO DIVERGE
BEYOND THURSDAY AS THE GFS IS FASTER IN EJECTING THE LOW INTO NORTH
CENTRAL MEXICO...THEN TRACKING IT ACROSS TEXAS AS A WEAK OPEN WAVE.
THE ECMWF CONTINUES TO BE MUCH SLOWER...HANGING THE LOW OFF THE
PACIFIC COAST THROUGH SATURDAY. THE BEST DYNAMICS WITH THIS LOW WILL
REMAIN WELL SOUTH OF WEST CENTRAL TEXAS...AND HAVE TRIMMED POPS BACK
SLIGHTLY...THURSDAY AND FRIDAY. WOULD NOT BE SURPRISED TO SEE A FEW
SHOWERS AS OCCASIONAL DISTURBANCES EMBEDDED IN THE SOUTHWEST FLOW
ALOFT MOVE OVER THE AREA. DO NOT EXPECT MUCH QPF...AS ANY SHOWERS
THAT DO DEVELOP LOOK TO BE LIGHT AS THIS TIME. IN
ADDITION...DIFFERENCES ARISE IN THE HANDLING OF THE NEXT UPPER LEVEL
TROUGH MOVING ACROSS THE PLAINS ON FRIDAY. THE ECMWF IS DEEPER THAN
THE GFS WITH THE TROUGH...HENCE MORE AGGRESSIVE WITH THE
FRONT...PUSHING IT THROUGH THE AREA ON FRIDAY. AS THE FRONT MOVES
THROUGH...THE ECMWF DEVELOPS SHOWERS ALONG THE BOUNDARY ON FRIDAY.
FOR NOW...HAVE LEFT FRIDAY DRY...BUT FUTURE SHIFTS WILL NEED TO
MONITOR. THE NEXT ISSUE IS THE NEXT UPPER LEVEL TROUGH THAT IS
FORECAST TO SWING ACROSS THE PLAINS SUNDAY INTO MONDAY. MODELS HAVE
BEEN FAIRLY CONSISTENT IN SHOWING INCREASING RAIN CHANCES AHEAD OF
THIS TROUGH...AND HAVE ADDED IN SLIGHT CHANCE POPS SUNDAY AND SUNDAY
NIGHT.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 28 47 32 56 37 / 0 10 10 10 20
SAN ANGELO 33 52 36 54 38 / 0 10 10 10 20
JUNCTION 36 56 39 56 39 / 10 10 10 20 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
306 PM MST WED FEB 8 2012
.SHORT TERM...
CURRENTLY SOME STRONGER WINDS INTO THE ARLINGTON AREA AS WELL AS
NEAR VEDAUWOO WITH SUSTAINED WINDS AROUND 40 MPH AND GUSTS
GENERALLY AROUND 50 MPH. THESE WINDS ARE LARGELY IN RESPONSE TO
THE SHORTWAVE CURRENTLY MOVING ACROSS THE BLACK HILLS OF SOUTH
DAKOTA. AS THE WAVE CONTINUES SOUTHEAST THIS AFTERNOON THE GRADIENT
WILL RELAX AND WIND WILL DECREASE. 2 KM WINDS OFF THE THE MEDICINE
BOW PROFILER MAY ALREADY BE SHOWING THIS AS MAGNITUDE DROPPED FROM
40 KTS TO 35 KTS. ALTHOUGH THE GRADIENT WILL DECREASE...MODELS
INDICATE A STABLE LAYER BEING PUSHED TO THE SURFACE THIS EVENING
AS SUBSIDENCE KICKS IN BEHIND THE SHORTWAVE. COULD SEE SOME GUSTY
WINDS LATER THIS EVENING INTO LATER TONIGHT FOR AREAS LEE OF THE
LARAMIE RANGE...MAINLY FROM INTERSTATE 25 WEST. NOT LOOKING AT
ANYTHING TOO STRONG...BUT 20 TO 25 MPH WITH GUSTS 30 TO 35 MPH
SEEM LIKE A GOOD BET.
FOG OVER THE NEBRASKA PANHANDLE THIS MORNING HAS LIFTED AND PUSHED
WELL TO THE EAST DUE TO MIXING AND LIGHT WESTERLY FLOW. NOT OVERLY
CONCERNED THAT FOG WILL REFORM TONIGHT ALTHOUGH NOT ABLE TO RULE
IT OUT COMPLETELY FROM ROUGHLY EAST OF A LINE FROM CHADRON TO
SYDNEY. GUIDANCE AND HRRR INDICATE FOG COULD FORM LATE TONIGHT IN
THIS AREA. THINKING IS LIGHT WESTERLY FLOW WILL KEEP WIDESPREAD
DENSE FOG AT BAY BUT DID ADD PATCHY FOG INTO THE WESTERN TIER OF
COUNTIES.
PRECIPITATION CHANCES TONIGHT WILL BE CONFINED TO AREAS WEST OF THE
LARAMIE RANGE...MAINLY OVER THE SNOWY AND SIERRIA MADRES. RADAR
INDICATING SOME PRECIPITATION ALREADY REACHING IN THE GROUND IN
THESE AREAS AND OLD BATTLE SNOWTEL SHOWED SOME LIGHT ACCUMULATION
THIS AFTERNOON. MAIN SURGE OF UPSLOPE MOISTURE WILL BE THIS
EVENING WHEN SEVERAL INCHES OF SNOW ARE LIKELY IN HIGHER
ELEVATION. SNOW WILL MOSTLY TAPER OFF BY LATE TONIGHT.
THURSDAY WILL BE A DRY WITH A WEAK RIDGE SHIFTING INTO THE AREA
BUT CHANCES FOR PRECIPITATION WILL INCREASE THURSDAY NIGHT INTO
FRIDAY AS AN UPPER TROUGH DIVES INTO THE NORTHERN PLAINS AND
ASSOCIATED ARCTIC FRONT BACKS INTO THE HIGH PLAINS. MODELS
STRUGGLING TO REACH CONSENSUS AS TO HOW FAR WEST THE FRONT WILL
MAKE IT AND TO THE PLACEMENT AND EXTENT OF SNOW. GFS HAS BEEN
CONSISTENTLY FARTHER EAST WITH THIS SYSTEM...KEEPING THE BULK OF
THE SNOW AND COLD AIR ACROSS WESTERN NEBRASKA. GEM...NAM...AND EC
ALL FARTHER WEST WITH THE EC BEING THE MOST BULLISH ON QPF
AMOUNTS. INCREASED POPS ACROSS THE CWA BUT CONFIDENCE IN AMOUNTS
AND PLACEMENT ARE CURRENTLY LOW. WILL WAIT TO SEE WHAT THE
UPCOMING MODELS BRING BUT IT SHOULD BE NOTED THAT WERE THE EC TO
VERIFY...SOME LOCATIONS ALONG AND LEE OF THE LARAMIE RANGE...COULD
PICK UP OVER 6 INCHES OF SNOW...INCLUDING CHEYENNE.
.LONG TERM...
SATURDAY WILL BE UNSEASONABLY COOL ACROSS THE CWA WITH STRATUS TO
THE EAST OF THE LARAMIE RANGE. A 1040MB SFC HIGH ACROSS THE PLAINS
WILL CAUSE SOUTHEASTERLY SFC UPSLOPE. BUMPED UP POPS INTO THE
SLIGHT CHANCE CATEGORY FOR AREAS EAST OF THE LARAMIE RANGE...HOWEVER
ANY SNOW AMOUNTS WILL BE VERY LIGHT. A SHORTWAVE RIDGE PROGRESSES OVER
THE AREA ON SAT NIGHT IN ADVANCE OF A LOW PRESSURE SYSTEM PROGGED TO
TRACK SOUTH OF THE CWA ON SUNDAY. THE STRONGEST DYNAMICS WILL BE
WELL SOUTH OF SOUTHEAST WY IN NEW MEXICO AND SOUTHERN CO. IN
ADDITION...WITH A SFC TROUGH FCSTED TO DEVELOP OVER WESTERN NEBRASKA
AND THE ASSOCIATED LACK OF UPSLOPE ON THE PLAINS...THIS SYSTEM WILL
BE PRIMARILY DRY FOR THE CWA. HOWEVER...CAN NOT RULE OUT A FEW SNOW
SHOWERS ACROSS THE SIERRA MADRE/SNOWY RANGE WITH MOISTENING 700MB
WESTERLY FLOW. THE GFS AND ECMWF AGREE ON DIGGING ANOTHER SYSTEM
INTO THE INTERMOUNTAIN WEST ON MONDAY. THE GFS SHOWS THE 700MB LOW
AND SFC LOW TRACKING ACROSS SOUTHERN CO ON TUESDAY...WITH LOW-LEVEL
NORTH AND NORTHEAST WINDS DEVELOPING ACROSS THE PLAINS. LOOKS LIKE
A BETTER SHOT AT PRECIP ON TUESDAY NIGHT/WEDNESDAY TO THE EAST OF
THE LARAMIE RANGE THAN WITH THE SUNDAY SYSTEM. THE ECMWF IS ABOUT
12 HOURS WITH THE UPPER TROUGH AND ASSOCIATED PRECIP DEVELOPMENT.
WILL CONTINUE TO MONITOR THE EVOLUTION OF THE TUESDAY/WEDNESDAY
SYSTEM DUE TO ITS POTENTIAL TO PRODUCE MODERATE SNOW ACCUMULATIONS.
&&
.AVIATION...18Z TAF ISSUANCE...
VISIBLE SATELLITE IMAGERY SHOWS THAT THE LOW CLOUDS HAVE CLEARED
OUT OVER THE WESTERN NEBRASKA PANHANDLE...EXCEPT FOR KAIA WHICH IS
ON THE WESTERN FRINGE OF THE LOW CLOUDS. INCLUDED TEMPO MVFR CIGS
THROUGH 19Z AT KAIA TO ACCOUNT FOR THE SLOWER CLEARING AT THIS
SITE. ELSEWHERE VFR CONDITIONS WILL PREVAIL THROUGH THE TAF
PERIOD. MID LEVEL CLOUDS WILL BE PERSISTENT ACROSS SOUTHEAST WY
WITH BKN VFR CIGS THROUGH THE EVENING.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS THE NEXT SEVERAL DAYS. A BIT BREEZY
THURSDAY FOR FAR SOUTHEAST WYOMING AND THE NEBRASKA PANHANDEL BUT
MIN RH WILL MAINLY BE ABOVE 35 PERCENT. CHANCE FOR SNOW ACROSS
MOST OF THE AREA FRIDAY WITH COLD AIR FILTERING INTO THE AREA
FRIDAY NIGHT. COOL AND UNSETTELED WEATHER INTO EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...LIEBL
LONG TERM/AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
406 AM EST FRI FEB 10 2012
...ARCTIC AIR POISED TO MAKE A RETURN TO THE LOWCOUNTRY AND
COASTAL EMPIRE THIS WEEKEND...
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
PRESCRIBED BURN ACTIVITIES ARE PRODUCING AREAS OF SMOKE ACROSS
PORTIONS OF BERKELEY COUNTY EARLY THIS MORNING. VISIBILITIES HAVE
BEEN AS LOW AS 2 MILES AT TIMES AT THE KMKS AWOS...BUT THE COUNTY
WARNING POINT INDICATES VISIBILITIES HAVE BEEN LOWER AT TIMES.
WILL CONTINUE TO HIGHLIGHT AREAS OF SMOKE IN OUR GRIDDED AND TEXT
FORECASTS...BUT CONDITIONS DO NOT SUPPORT DENSE SMOKE ADVISORY
CRITERIA ATTM.
10/08Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 NM AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS...AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW
OVERNIGHT...CONTRIBUTING TO WIND CHILL VALUES POSSIBLY IN THE
TEENS. RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA
WITH SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
LOW-END VFR CIGS HAVE MOVED INTO THE KCHS-KSAV CORRIDOR ALONG THE
LEADING EDGE OF ISENTROPIC ASSENT. EXPECT LOW-END VFR OR HIGH-END
MVFR CIGS TO DOMINATE THROUGH SUNRISE WITH INCREASING
PROBABILITIES FOR PREVAILING MVFR CIGS THEREAFTER. SHOWER ACTIVITY
WILL INCREASE LATER THIS MORNING WITH THE GREATEST COVERAGE
OCCURRING EAST OF I-95 THIS AFTERNOON. TIMING AND INTENSITY
UNKNOWN SUPPORT KEEPING SHOWERS OUT OF BOTH TAFS SITES
ATTM...HOWEVER AT SOME POINT MVFR VSBYS ARE EXPECTED IN SHOWERS...
ESPECIALLY AT KCHS.
EXTENDED AVIATION OUTLOOK...MVFR CIGS AND/OR VSBYS COULD AFFECT
THE TERMINALS THROUGH FRIDAY NIGHT...AS A WAVE OF LOW PRESSURE
LIFTS WELL OFF THE COAST OF THE SOUTHEAST UNITED STATES. IN
ADDITION...GUSTY WINDS WILL BECOME A CONCERN SATURDAY...WITH LLWS
POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD IMPACT THE TERMINALS
AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM MOVES THROUGH THE AREA.
&&
.MARINE...
TODAY...THE REGION IS POSITIONED NORTH OF A SHARPENING COASTAL
TROUGH ALONG THE FLORIDA EAST COAST THIS MORNING. THIS IS YIELDING
A SOLID NORTHEAST WIND REGIME WITH SPEEDS GENERALLY BELOW 15 KT.
NORTHEAST WINDS WILL DOMINATE FOR MUCH OF THE DAY BEFORE VEERING
MORE SOUTHERLY THIS AFTERNOON AS THE COASTAL TROUGH BREAKS DOWN
AND A COLD FRONT APPROACHES FROM THE WEST. BOTH WINDS AND SEAS
WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1154 PM CST THU FEB 9 2012
.AVIATION...
STRATUS WITH VFR TO MVFR CIGS WILL PERSIST THROUGH THU AM. ARCTIC
FRONT TO PASS THROUGH TERMINALS BETWEEN ROUGHLY 10Z-14Z. W/SW
WINDS AROUND 10 KTS AHEAD OF FRONT WILL SHIFT TO NW AND BECOME
GUSTY AT 15-30 KTS WITH FRONTAL PASSAGE. MAY BE BRIEF WINDOW
OF PARTIAL CLEARING PRIOR TO FROPA ESPECIALLY AT KCID... AND SOME
LIGHT FOG WITH 3-5SM VSBY POSSIBLE. OTRW... CIGS MORE WIDESPREAD
MVFR THU AM AS MUCH COLDER AIR OVERTAKES REGION. FLURRIES WILL
LIKELY BE WRUNG OUT WITH THE COLD ADVECTION WITH FEW SHSN POSSIBLE
BY MID AM THROUGH EARLY AFTN AS ATMOSPHERE BECOMES MORE UNSTABLE.
MODELS WANT TO KEEP A LOT OF LOW LEVEL MOISTURE AROUND THU NGT
BUT SATL AND OBS POST FRONTAL SHOW LOW CLOUDS NOT LASTING MORE
THAN ABOUT 4-6 HRS OR SO AFTER FROPA BEFORE SCOURING OUT WITH STRONG
SUBSIDENCE. THEREFORE.. CONTINUED TRENDS OF DECREASING LOW CLOUDS
DURING AFTN THROUGH SUNSET. WINDS TO REMAIN GUSTY 15-20+ KTS THU
NGT.
&&
.PREV DISCUSSION... /ISSUED 305 PM CST THU FEB 9 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS SEVERAL SHORTWAVE TROFS FROM THE GREAT LAKES
BACK INTO THE PLAINS. AN 850MB COLD FRONT RAN FROM CANADIAN UA SITE
CYEG IN ALBERTA PROVINCE TO THE SOUTH EDGE OF JAMES BAY. SATELLITE
TRENDS THROUGH MID AFTERNOON SHOW THE LOW CLOUDS MOVING EAST ACROSS
THE AREA WITH CLEARING ACROSS SOUTHERN MINNESOTA AND WISCONSIN. THE
LOW POST FRONTAL CLOUDS OF THE ARCTIC FRONT WERE ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA.
18Z SFC ANALYSIS HAD A RIDGE RUNNING FROM THE LOWER MISSISSIPPI
VALLEY INTO THE OHIO VALLEY. THE ARCTIC FRONT RAN FROM EASTERN
MONTANA INTO NORTHWEST MINNESOTA. DEW POINTS ACROSS THE MIDWEST WERE
GENERALLY IN THE TEENS AND 20S WITH 30S IN THE SOUTHERN PLAINS AND
EASTERN KANSAS.
SHORT TERM...TONIGHT AND FRIDAY...
THE SHALLOW NATURE OF THE CLOUDS...ROUGHLY 1-2KFT...IS ONE OF MANY
REASONS WHY THE MODELS ARE DOING AN EXTREMELY POOR JOB OF DEPICTING
THEM AND HANDLING THEIR OVERALL MOVEMENT. THESE CLOUDS PLAY
SIGNIFICANTLY INTO SENSIBLE WX TRENDS TONIGHT BEFORE THE ARCTIC
FRONT ARRIVES.
THE RUC AND WRF HAVE A VAGUE IDEA ABOUT THE CLOUDS AND EITHER THE
0.5-1KM LAYER OR 0.5KM LAYER IS AT LEAST HINTING AT THE CLOUDS.
USING THIS ALONG WITH EXTRAPOLATION FROM CURRENT SATELLITE TRENDS
RESULTS IN CLOUDY SKIES FOR THE REMAINDER OF THE AFTERNOON AND INTO
THE EVENING HOURS. BASED ON THE CURRENT CLEAR AREA TO THE NORTH AND
WHAT THE MODELS ARE SUGGESTING...THE CLOUDS SHOULD PARTIALLY BREAK
UP ACROSS THE NORTHERN THIRD OF THE CWFA LATE THIS EVENING. WHAT
PARTIAL CLEARING THAT DEVELOPS WILL BE FORCED SOUTH AFTER MIDNIGHT
AS THE ARCTIC FRONT STARTS MOVING INTO THE CWFA.
BECAUSE OF THE CLOUDS...TEMPERATURES WILL BE WARMER THAN LAST NIGHT.
ANY AREAS THAT DO SEE PARTIAL OR A TOTAL CLEARING SHOULD DROP AND
THEN REBOUND AS THE POST FRONTAL CLOUDS OF THE ARCTIC FRONT ARRIVE.
THE CAA BEHIND THE ARCTIC FRONT IS IMPRESSIVE. LOW TEMPERATURES
TONIGHT WILL LIKELY OCCUR 7-8 AM FRIDAY MORNING.
ON FRIDAY...THE ARCTIC FRONT WILL CLEAR THE CWFA BY MID TO LATE
MORNING WITH POST FRONTAL STRATUS CLOUDS FOLLOWING BEHIND IT. THE
COMBINATION OF CAA...STRONG CYCLONIC FLOW ALOFT...A STRONG VORT
MAX...STEEPENING LOW LEVEL LAPSE RATES...AND THE STRONGER FEBRUARY
SUN ALL POINT TO SNOW SHOWERS DEVELOPING FROM LATE MORNING THROUGH
THE AFTERNOON. FCST SOUNDINGS DO SHOW SOME SMALL CAPE DEVELOPING AS
LAPSE RATES STEEPEN. PRIOR TO THE SNOW SHOWERS DEVELOPING THERE ARE
REASONABLY LOW CONDENSATION PRESSURE DEFICITS WITH SOME FORCING AND
F VECTOR CONVERGENCE. THUS FLURRIES MAY BE POSSIBLE WITH THE POST
FRONTAL STRATUS BEFORE THE SNOW SHOWERS DEVELOP.
SNOW AMOUNTS WITH THE SNOW SHOWERS WILL BE VARIED. AMOUNTS COULD
RANGE FROM ONLY A TRACE TO AROUND ONE HALF INCH IN THE STRONGER
SHOWERS.
WINDS WILL BE QUITE BRISK ON FRIDAY AND MAY BE LOCALLY STRONGER
AROUND SNOW SHOWERS.
MAX TEMPERATURES FRIDAY WILL LIKELY OCCUR 9-11 AM WITH TEMPERATURES
EITHER STEADY OR SLOWLY FALLING DURING THE AFTERNOON. ..08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
SEASONALLY COLD...A LIGHT SNOW EVENT MONDAY WITH A MODEST WARMING
TREND INTO MIDDLE OF NEXT WEEK.
OVERALL...LARGE SCALE FEATURES REASONABLE BUT LOW LEVEL BL PROBLEMS
CONTINUE WITH MOST SOLUTIONS T/TD PROFILES LOWEST 2K AGL STILL OFF.
MAIN CONTRIBUTOR IS OUR UNSEASONABLY LOW AMOUNTS OF SNOW NOT HANDLED
BY PHYSICS PACKAGES. THIS IS RESULTING IN BL FORECASTS...ESPECIALLY
AMERICAN SOLUTIONS EITHER TOO MOIST OR TOO DRY. INITIALIZATION AND
VERIFICATION AGAIN SUGGESTS A HIGHER WEIGHT BE GIVEN TO COLDEST
GUIDANCE FOR MIN TEMPERATURES WITH ARCTIC AIR IF NOT A FEW DEGREES
COLDER. FOR HIGHS...ON THE WARM END FOR MAX TEMPS INTO MONDAY.
TEXTBOOK WIDESPREAD LIGHT SNOW EVENT MONDAY WITH LOCAL TOOLS
SUGGESTING .5 TO 1.5 INCHES OF SNOW MOST LOCATIONS AT THIS TIME. NEXT
24 HOURS...FINER DETAILS MAY SUGGEST A LEAD VORT MAX...THEN SOME
ISOLATED 2 TO 3 INCHES NOT OUT OF THE QUESTION...THIS SHOULD BE KNOWN
THIS TIME TOMORROW.
FRIDAY NIGHT...CLEARING WITH STRONG CAA WITH NW WINDS 10-20+ MPH IN
THE EVENING DECREASING TO 5-10 MPH OVERNIGHT. LOCAL TECHNIQUES
SUPPORT 0-5F ABOVE NW 1/2 AND 5-10F ABOVE SE 1/2. WHEN ADJUSTING FOR
BL PROBLEMS...POSSIBLE MINS MAY STILL BE 2-5 DEGREES TOO MILD FOR
MANY IF NOT MOST LOCATIONS FOR LATER SIFTS TO REASSESS.
SATURDAY AND SUNDAY...FAIR AND COLD WITH HIGHS UPPER TEENS TO MID 20S
BOTH DAYS AND LOWS SUNDAY AM IN THE SINGLE DIGITS WITH SOME BELOW
ZERO READINGS AGAIN POSSIBLE NW SECTIONS. SUNDAY NIGHT...INCREASING
CLOUDS LATE WITH MINS IN THE TEENS WITH SLOWLY RISING TEMPERATURES
POSSIBLE AFTER MIDNIGHT.
MONDAY... UPPED POPS TO LOW END LIKELY TO HIGH END CHANCE WITH AREAS
OF LIGHT SNOW TO OVERSPREAD AREA THROUGH MONDAY NIGHT. LOCAL TOOLS
SUGGEST MOSTLY .5-1.5 INCHES ATTM WITH RISK OF SOME ISOLATED HIGHER
AMOUNTS OF 2-3 INCHES POSSIBLE IF LEAD VORT MAX IS STRONGER. BL
ISSUES MAKE THIS A CHALLENGE THAT LATER SHIFTS WILL NEED TO STAY ON
TOP OF. HIGHS NEAR FREEZING WITH SOUTH WINDS LIMITING ACCUMULATIONS
ON THE MOST TRAVELED ROADS. MONDAY...LIGHT SNOW TO DIMINISH TO
FLURRIES OR END BY LATE OVERNIGHT HOURS. WITH MINOR ACCUMULATIONS IN
THE FAR EAST UNTIL MIDNIGHT. LOWS WITH CLEARING IN THE NW SECTIONS
MAY NEED TO BE TRIMMED FURTHER BY 2 TO 5 DEGREES.
TUESDAY THROUGH THURSDAY...DRY TO MOSTLY DRY WITH LOW CHANCE POPS ON
WEDNESDAY AND THURSDAY...MOSTLY LOWER SOUTH SECTIONS. MAIN FORCING
IS SUGGESTED TO PASS TO THE SOUTH SO ANY AMOUNTS TO BE LIGHT IF NOT
DRY. LATER SHIFTS MAY BE ABLE TO REMOVE POPS MANY LOCATIONS THE NEXT
FEW DAYS. TEMPERATURES OVERALL TO TREND NEAR TO SLIGHTLY ABOVE
NORMAL. ..NICHOLS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
937 PM MST THU FEB 9 2012
.DISCUSSION...
225 PM MST THU FEB 9 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS HIGHLY
AMPLIFIED RIDGE ACROSS THE PACIFIC COAST AND A LARGE SCALE TROUGH
ACROSS SOUTHERN CANADA/NORTHERN GREAT LAKES. A SHORTWAVE TROUGH
BETWEEN THESE FEATURES EXTENDS ACROSS THE NORTHERN PLAINS...WITH
ITS MEAN AXIS ALONG THE COLORADO/KANSAS STATE LINE.
TONIGHT...THE UPPER TROUGH CURRENTLY MOVING OVER THE CENTRAL HIGH
PLAINS REGION MOVES EAST OF THE AREA TONIGHT. SUBSIDENCE AND
DRYING ALOFT MOVE OVER IN THE WAKE OF THE TROUGH WITH A GENERAL
DECREASE IN SKY COVER. HIGH PRESSURE OVER THE NORTHERN PLAINS
BEGINS TO MOVE INTO THE REGION WITH WINDS REMAINING OUT OF THE
NORTH-NORTHWEST. WITH A COLDER AREA OF HIGH PRESSURE MOVING
IN...EXPECT TEMPERATURES TONIGHT AND EARLY FRIDAY TO BE NEARLY 10
TO 15 DEGREES COOLER AT MOST LOCATIONS ACROSS THE FORECAST AREA.
LOCKHART
FRIDAY-SUNDAY...COLD AIRMASS SETTLES IN OVER CWA AS A COLD FRONT
MOVES SOUTH OVER CWA AND STRONG SURFACE HIGH BUILDS OVER NORTHERN
PLAINS. A LARGE TEMPERATURE GRADIENT WILL SET UP ACROSS THE SW
PART OF THE CWA. WHILE TEMPS IN THE EXTREME SW CWA MAY REMAIN NEAR
NORMAL DURING THESE PERIODS...THE REST OF THE AREA WILL EXPERIENCE
DAYTIME TEMPS BELOW FREEZING.
DEEP EASTERLY UPSLOPE DEVELOPS BY FRIDAY EVENING WITH ATMOSPHERE
SATURATING BENEATH H7 ACROSS THE CWA. BETTER MID LEVEL MOISTURE/LIFT
WILL SUPPORT SNOW MAINLY OVER THE NORTHERN PART OF THE CWA FRIDAY
NIGHT WHERE AROUND AN INCH OF SNOW IS EXPECTED. BIGGER STORY MAY END
UP BEING THE POTENTIAL FOR FREEZING DRIZZLE AND FREEZING FOG FROM
THE BL TO H7 AROUND -10C FOR MUCH OF THESE PERIODS. THIS COULD
SUPPORT BOTH SUPER COOLED LIQUID AS WELL AS ICE CRYSTALS IN
LOCATIONS IN THE WEST WHERE MID LEVELS ARE MUCH DRIER. THERE
SHOULD ALSO BE BETTER CHANCES FOR DENSE FOG/FREEZING DRIZZLE IN
THE WEST WHERE MOISTURE POOLING ALONG BAROCLINIC ZONE IS MORE
LIKELY. FOR NOW NOT EXPECTING A LOT OF ICE ACCUMULATION...THOUGH A
FEW HUNDREDTHS OF AN INCH COULDNT BE RULED OUT IN THE WEST. IN ANY
CASE A PERIOD OF LIGHT MIXED PRECIP/FOG/LOW STRATUS LOOKS TO BE IN
STORE FRIDAY NIGHT THROUGH EARLY SATURDAY MORNING.
STRATUS/FOG POTENTIAL WILL CONTINUE THROUGH SATURDAY NIGHT/EARLY
SUNDAY MORNING...WITH LITTLE CHANGING IN REGARDS TO UPSLOPE FLOW AND
SURFACE HIGH PRESSURE. AS WEAK SHORTWAVE ENERGY CONTINUES TO PASS
AROUND GREAT LAKES UPPER LOW...I CANT RULE OUT SNOW ACROSS THE
EASTERN CWA THROUGH SUNDAY NIGHT...WHERE I KEPT SLIGHT CHANCE POPS
IN PLACE.
MONDAY-MONDAY NIGHT...SHORTWAVE RIDGE BUILDS IN FROM THE WEST...WHICH
SHOULD HELP BRING NEAR NORMAL TEMPS BACK TO CWA. GUIDANCE STILL
INDICATING LIFT/MOISTURE LINGERING OVER EASTERN PART OF THE CWA...SO
I KEPT SLIGHT CHANCE POPS GOING THROUGH THE DAY. IF OTHER GUIDANCE
TRENDS TOWARDS FASTER NAM SOLUTION THESE POPS COULD PROBABLY BE
REMOVED.
TUESDAY-THURSDAY...NOT A LOT OF CONFIDENCE IN THE FORECAST DURING
THESE PERIODS WITH A LOT OF SPREAD IN REGARDS TO SMALLER SCALE
FEATURES WITHIN A FAIRLY CHAOTIC QUASI-ZONAL PATTERN. ECMWF AND GFS
CONTINUE TO DIFFER ON THE EVOLUTION OF SHORTWAVE TROUGHS ON
WEDNESDAY AND THURSDAY...WHERE BOTH MODELS HAVE BEEN TRYING TO
PRODUCE PRECIP FOR DIFFERENT PARTS OF THE CENTRAL HIGH PLAINS. ECMWF
HAS SHOWN BETTER RUN-RUN CONSISTENTLY THUS FAR...AND WOULD FAVOR A
DRY SOLUTION FOR OUR CWA. GFS CONTINUES TO FAVOR A WETTER
SOLUTION...BUT HAS BEEN LESS CONSISTENT ON THE PLACEMENT OF QPF
BETWEEN MODEL RUNS. FOR NOW I KEPT SLIGHT CHANCE POPS IN PLACE
WEDNESDAY THROUGH THURSDAY TO ACCOUNT FOR THE SPREAD IN SOLUTIONS
AND THE UNCERTAINTY AT THIS RANGE. WAS NOT CONFIDENT ENOUGH TO STRAY
TO FAR FROM NORM ON TEMPS CONSIDERING MODEL SPREAD EACH DAY.
DR
&&
.AVIATION...
937 PM MST THU FEB 9 2012
FOR THE 06Z TAFS...VFR AT BOTH TERMINALS THROUGH FRIDAY MIDDAY.
AFTERWARDS...EASTERLY UPSLOPE WINDS WILL LEAD TO MVFR STRATUS
FORMATION FIRST AT KMCK THEN AT KGLD. AFT 00Z...MID LEVEL FORCING
INCREASES AND WITH SATURATED LOW/MID LEVELS...LIGHT SNOW WILL
BECOME POSSIBLE...ESPECIALLY AT KGLD. IF LIGHT SNOW
MATERIALIZES...EXPECT POSSIBLE IFR CIGS/VIS THROUGH END OF TAF
PERIOD.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
346 AM EST FRI FEB 10 2012
LATEST UPDATE...ALL BUT AVIATION...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(346 AM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMININSH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(1158 PM EST THU FEB 9 2012)
EXPECT 3 TO 5 HOURS OF LIFR CIGS/VSBY WITH SNOW AT ALL TAF SITES
DURING FROM LATE MORNING INTO EARLY EVENING FRIDAY.
THE LOW CLOUDS (MVFR CIGS STREAMED IN FROM LAKE MICHIGAN EARLIER
THAN EXPECTED SO I UPDATED THE TAFS ALREADY TO ACCOUNT FOR THAT AND
BELIEVE THEY WILL REMAIN ALL NIGHT INTO FRIDAY.
THE NEXT ISSUE IS WILL THERE BE LAKE ENHANCED SOUTHWEST FLOW SNOW
SHOWERS AHEAD OF THE ARCTIC FRONT AT MKG...GRR AND AZO BTW 12Z AND
16Z? THE 950 TO 850 RH IS MARGINALLY HIGH ENOUGH AND THERE IS SOME
LIFT IN THE DGZ TOO. THE HRRR SHOWS THIS ALSO BUT THE RH BECOMES
LOWER AS ONE IS FARTHER SOUTH FROM THE PRIMARY COLD FRONT SO I HAVE
THE SNOW STARTING EARLY AT MKG BUT NOT SO MUCH AT GRR AND AZO. THAT
WILL HAVE TO BE WATCHED.
THE BIGGEST CHANGE IS THAT THE NAM AND GFS ARE MUCH STRONGER ON THE
SURFACE LOW FOR FRIDAY AFTERNOON. THIS CREATES A SIGNIFICANTLY
LONGER PERIOD OF SNOW AND IT THE SNOW WOULD CONTINUE PAST SUNSET AT
LOCATIONS EAST OF GRR. LIFR CONDITIONS WOULD SEEM LIKELY AT MOST TAF
SITES FRIDAY AFTERNOON DUE TO SNOW AND MAYBE EVEN BLOWING SNOW AS
THE COLD AIR BECOMES MORE ENTRENCHED WHILE THE LOW LEVEL WINDS KICK
UP AFTER 21Z. WE WILL HAVE TO MONITOR THIS TOO. CONDITIONS WOULD
NOT IMPROVE MUCH UNTIL AFTER 03Z AT MOST TAF SITES.
&&
.MARINE...(346 AM EST FRI FEB 10 2012)
WE/LL SEE AN ABRUPT WIND SHIFT TODAY AS A STRONG COLD FRONT MOVES
THROUGH. WINDS WILL GUST FROM THE NORTH BEHIND THE FRONT TO JUST
UNDER GALE FORCE AND THEN DIMINISH OVERNIGHT. AS TEMPS FALL BELOW
FREEZING LATER THIS AFTERNOON AND TONIGHT...THE GUSTY WINDS MAY
RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THIS AFTERNOON AND EVENING FOR ALL BUT
THE NORTHERN TWO ROWS OF COUNTIES.
LM...SMALL CRAFT ADVISORY THROUGH SATURDAY.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93
LONG TERM: MJS
AVIATION: WDM
MARINE: 93
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1158 PM EST THU FEB 9 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(320 PM EST THU FEB 9 2012)
AN ARCTIC COLD FRONT WILL SWEEP SOUTH THROUGH LOWER MICHIGAN FRIDAY
AND PRODUCE AN INCH OR TWO OF SNOW. AN ABRUPT DROP IN TEMPERATURES
BEHIND THE FRONT MAY CAUSE HAZARDOUS TRAVEL AS ROADS TURN ICY. THE
FRIDAY EVENING COMMUTE COULD BE A SLOW ONE WITH SOME SLIDE OFFS
POSSIBLE.
WINDS TURN TO THE NORTH BEHIND THE FRONT FRIDAY NIGHT SO LAKE EFFECT
SNOW SHOWERS WILL BE MOSTLY OFFSHORE EXCEPT AROUND LUDINGTON. SOME
LIGHT ACCUMULATIONS ARE POSSIBLE SATURDAY AND SATURDAY NIGHT WEST OF
HIGHWAY 131 AS THE WINDS BECOME NORTHWESTERLY.
&&
.SHORT TERM...(320 PM EST THU FEB 9 2012)
(TONIGHT THROUGH SATURDAY NIGHT)
THE MAIN FOCUS IN THE SHORT TERM IS THE ARCTIC FRONT FOR FRIDAY AND
IT/S POTENTIAL IMPACT.
GUIDANCE CONTINUES TO SUGGEST A QUICK BURST OF ABOUT ONE INCH OF
SNOW ALONG THE ARCTIC BOUNDARY FRIDAY. TWO INCHES IS POSSIBLE IN THE
ERN CWFA AROUND LAN AND JXN. THIS IS NOT A BIG DEAL AT ALL FOR
FEBRUARY IN LWR MI... BUT IT MAY STILL HAVE SIGNIFICANT TRAVEL
IMPACT.
ASSUMING THE ONE INCH OR SO OF SNOW DOES ACCUMULATE WITH THE
FRONT... THE ABRUPT TEMPERATURE FALL BEHIND THE FRONT MAY LEAD TO
RAPID FORMATION OF VERY ICY ROADS AS TEMPS FALL FROM LOW TO MID 30S
DOWN INTO THE 20S AND TEENS.
HAZARDOUS TRAVEL CONDITIONS WITH SLOW DOWNS AND SLIDE OFFS COULD
DEVELOP DUE TO THE ABRUPT WEATHER CHANGE. THIS COMES AFTER A LENGTHY
PERIOD OF NO WINTER WEATHER AND SAFE TRAVEL... AND MAY CATCH SOME
DRIVERS A BIT OFF GUARD.
OF PARTICULAR CONCERN WILL BE THE INTERSTATE 96 CORRIDOR REGION
SOUTHWARD. THIS MORE DENSELY POPULATED REGION WILL LIKELY HAVE
RELATIVELY HIGH TRAVEL VOLUMES WHEN THE POTENTIAL HAZARD DEVELOPS IN
THE AFTERNOON AND EVENING WHICH INCLUDES THE FRIDAY EVENING/WEEK
END DRIVE HOME COMMUTE.
CONFIDENCE IS STILL SOMEWHAT LOW HOWEVER AT THIS TIME REGARDING
AREAL COVERAGE OF SNOW AMOUNTS AND IF THERE WILL EVEN BE ENOUGH TO
CAUSE SIGNIFICANT TRAVEL IMPACTS. BEST CHANCE FOR IMPACT IS FROM GRR
TO THE EAST AND SOUTHEAST.
ONCE THE SYNOPTICALLY INDUCED SNOW ALONG THE SFC FRONT DEPARTS
FRIDAY EVENING... DRY/COLD NORTH FLOW BEHIND THE FRONT RESULTS IN
DRY WEATHER FOR THE BULK OF THE CWFA WITH THE EXCEPTION OF THE
LUDINGTON AREA. THE LOW LEVEL FLOW DOES BACK TO THE NW ON
SATURDAY... WHICH COULD RESULT IN SOME ACCUMULATIONS WEST OF HIGHWAY
131. SOUTH HAVEN NAM BUFKIT HAS A DECENT OMEGA/DGZ CROSS HAIR
SIGNATURE IN THE CLOUD LAYER SATURDAY AND SATURDAY NIGHT... SO THIS
WILL NEED TO BE MONITORED.
&&
.LONG TERM...(320 PM EST THU FEB 9 2012)
(SUNDAY THROUGH THURSDAY)
FAIR WX IS ANTICIPATED SUNDAY WITH PARTLY SUNNY SKIES AND TEMPS
MODERATING SLIGHTLY TO CLOSER TO NORMAL. THERE IS A CHANCE OF LIGHT
WARM AIR ADVECTION SNOW MONDAY AFTERNOON THROUGH MONDAY NIGHT INTO
TUESDAY. DEEP MOISTURE WILL BE IN PLACE BUT FORCING/OMEGAS WILL BE
VERY WEAK SO ANY SNOW ACCUMULATIONS WILL BE VERY LIGHT.
A BRIEF PERIOD OF DRY WX WILL RETURN LATE TUESDAY THROUGH TUESDAY
NIGHT AND WEDNESDAY. BEYOND THAT A CONSENSUS OF LATEST MEDIUM RANGE
GUIDANCE CONTINUES TO SUGGEST THAT A SOUTHERN STREAM SYSTEM WILL
DEVELOP AND POTENTIALLY TRACK ENE TOWARD OUR REGION LATE NEXT WEEK.
THERE IS STILL A CONSIDERABLE AMOUNT OF UNCERTAINTY REGARDING THE
EXACT TRACK/STRENGTH OF THAT SYSTEM THAT FAR OUT IN TIME THOUGH. IT
IS ALSO NOTED THAT THE 12Z ECMWF HAS BACKED OFF ON THIS NOTION.
TEMPS WILL AVERAGE NEAR NORMAL SUNDAY AND MONDAY BEFORE MODERATING
TO AROUND FIVE TO FIFTEEN DEGREES ABOVE NORMAL TUESDAY THROUGH
THURSDAY.
&&
.AVIATION...(1158 PM EST THU FEB 9 2012)
EXPECT 3 TO 5 HOURS OF LIFR CIGS/VSBY WITH SNOW AT ALL TAF SITES
DURING FROM LATE MORNING INTO EARLY EVENING FRIDAY.
THE LOW CLOUDS (MVFR CIGS STREAMED IN FROM LAKE MICHIGAN EARLIER
THAN EXPECTED SO I UPDATED THE TAFS ALREADY TO ACCOUNT FOR THAT AND
BELIEVE THEY WILL REMAIN ALL NIGHT INTO FRIDAY.
THE NEXT ISSUE IS WILL THERE BE LAKE ENHANCED SOUTHWEST FLOW SNOW
SHOWERS AHEAD OF THE ARCTIC FRONT AT MKG...GRR AND AZO BTW 12Z AND
16Z? THE 950 TO 850 RH IS MARGINALLY HIGH ENOUGH AND THERE IS SOME
LIFT IN THE DGZ TOO. THE HRRR SHOWS THIS ALSO BUT THE RH BECOMES
LOWER AS ONE IS FARTHER SOUTH FROM THE PRIMARY COLD FRONT SO I HAVE
THE SNOW STARTING EARLY AT MKG BUT NOT SO MUCH AT GRR AND AZO. THAT
WILL HAVE TO BE WATCHED.
THE BIGGEST CHANGE IS THAT THE NAM AND GFS ARE MUCH STRONGER ON THE
SURFACE LOW FOR FRIDAY AFTERNOON. THIS CREATES A SIGNIFICANTLY
LONGER PERIOD OF SNOW AND IT THE SNOW WOULD CONTINUE PAST SUNSET AT
LOCATIONS EAST OF GRR. LIFR CONDITIONS WOULD SEEM LIKELY AT MOST TAF
SITES FRIDAY AFTERNOON DUE TO SNOW AND MAYBE EVEN BLOWING SNOW AS
THE COLD AIR BECOMES MORE ENTRENCHED WHILE THE LOW LEVEL WINDS KICK
UP AFTER 21Z. WE WILL HAVE TO MONITOR THIS TOO. CONDITIONS WOULD
NOT IMPROVE MUCH UNTIL AFTER 03Z AT MOST TAF SITES.
&&
.MARINE...(320 PM EST THU FEB 9 2012)
BRISK SOUTHWEST TO WEST FLOW WILL SHIFT NORTH BEHIND THE ARCTIC
FRONT ON FRIDAY. BRISK NORTHWEST WINDS CONTINUING FOR SATURDAY AND
SUNDAY AS CYCLONIC FLOW AND COLD AIR IMPACTS THE REGION.
WINDS AND WAVE WILL REMAIN HAZARDOUS TO SMALL CRAFT THROUGH THE
WEEKEND. FREEZING SPRAY COULD BE AN ISSUE AS WELL FOR FRIDAY NIGHT
AND BEYOND... AND MAY REQUIRE AN ADVISORY FOR ICE ACCRETION.
&&
.HYDROLOGY...(320 PM EST THU FEB 9 2012)
AREA RIVERS CONTINUE TO SLOWLY FALL. LIMITED QPF THROUGH THE WEEKEND
WILL RESULT IN THE SLOW FALL CONTINUING. ICE FORMATION ON THE RIVERS
AND THE POTENTIAL FOR ICE JAMS SHOULD INCREASE OVER THE WEEKEND
AS THIS BRIEF BOUT OF ARCTIC AIR IMPACTS THE REGION.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY THROUGH SATURDAY.
&&
$$
SYNOPSIS: MEADE
SHORT TERM: MEADE
LONG TERM: LAURENS
AVIATION: WDM
MARINE: MEADE
HYDROLOGY: MEADE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1143 PM CST THU FEB 9 2012
.AVIATION... /06Z TAF ISSUANCE/
A COLD FRONT WILL MOVE THROUGH KEAU BETWEEN 06Z-07Z. BRISK
NORTHWEST WINDS AT 15 TO 20 KNOTS WILL CONTINUE AT THE TAF SITES
IN THE WAKE OF THE FRONT...THEN SLOWLY DIMINISH ON FRIDAY. SOME
LIGHT SNOW SHOWERS MAY BRUSH KEAU OVERNIGHT WITH TEMPORARY MVFR
VISIBILITY. CLOUD TRENDS ARE ANOTHER CONCERN. IT IS BECOMING
APPARENT THAT THE LOW LEVEL MOISTURE IS WAY OVERDONE ON THE NAM
WITH VFR CEILINGS FROM CENTRAL MN NORTHWARD. SO...KMSP...KRNH AND
KEAU MAY ONLY SEE A FEW HOURS OF MVFR EARLY THIS MORNING.
HOWEVER...AS THE LOW LEVEL FLOW TURNS NORTHEAST...THE FLOW WILL BE
COMING OFF LAKE SUPERIOR BY FRIDAY MORNING AND THIS MAY BRING
ANOTHER ROUND OF MVFR CEILINGS TO THE AFOREMENTIONED SITES.
CONFIDENCE IS HIGH ON THE LOW CLOUDINESS BUT NOT ON WHETHER OR NOT
THE CEILINGS WILL BE MVFR.
KMSP...NORTHWEST WINDS AT 15 TO 20 KNOTS OVERNIGHT WITH GUSTS
FROM 25 TO 30 KNOTS. CONFIDENCE IS NOT HIGH THAT MVFR CEILINGS
WILL PERSIST THROUGH FRIDAY MORNING. IT MAY BE BROKEN INTO TWO
WAVES...ONE NOW THROUGH 10Z WITH ANOTHER 14Z-18Z ON FRIDAY. USED
BKN035 FOR FRIDAY MORNING.
&&
.DISCUSSION... /ISSUED 241 PM CST THU FEB 9 2012/
ARCTIC COLD FRONT WITH DECENT PRESSURE FALLS OVER NORTH DAKOTA DROPPING
SOUTH ABOUT AS FORECAST. NOT TOO MANY SITES REPORTING SNOW BUT
A COUPLE OF SITES IN NW ONT WERE DOWN TO AROUND 2SM. THE LATEST RUC
AND THE NAM TO A LESSER EXTENT DO FORECAST AN INCREASE IN QG VERT
VEL AND FGEN TO OUR NE AS THE FRONT DROPS SOUTH WILL INCREASE POPS
TO A CHANCE CATEGORY OVER IN WEST CENTRAL WI TO ACCOUNT FOR THIS.
WITH THE FRONT MOVING DOWN WILL GO WITH A MODEL WEIGHTED DIURNAL
TEMP TREND OVERNIGHT. SOME GUSTY WINDS FOR A TIME WITH THE COLD
ADVECTION TOO. NOT MUCH TEMP CHANGE FROM THE MORNING IN THE SE
FOR FRIDAY HIGHS.
FEEL THAT THE NAM IS OVERDOING THE LOW LEVEL MOISTURE FIELDS ON
FRIDAY WITH THE GFS AND RUC LOOKING BETTER AT LEAST IN THE MN
PORTION OF THE AREA. COLD ADVECTION OS THERE...BUT WE LOOSE THE
CYCLONIC CURVATURE IN THE AFTERNOON. LOOKS LIKE A COLD LOOKS
COLD FRIDAY NIGHT UNDER CLEAR SKIES BUT WITH A PRES GRADIENT
CONTINUING. MOST SITES LIKELY BELOW ZERO BUT THIS REGIME IS NOT
AS COLD AS THE MID JANUARY BLAST.
MODERATION BEGINS LATE IN THE WEEKEND AND EARLY NEXT WEEK WITH A
RETURN TO A MORE WESTERLY FLOW BUT SOMEWHAT SPLIT WITH MORE
BLOCKING AROUND THE NORTHERN HEMISPHERE. WE STILL HAVE A CHANCE OF
SNOW FOR SOUTHERN AREAS MONDAY AND MONDAY NIGHT WITH A CENTRAL
PLAINS TROUGH. PRECIP PROBS BETTER IN THE CENTRAL PLAINS THOUGH.
THERE HAD BEEN SOME CHANCE AGAIN LATER WEDNESDAY AND THURSDAY BUT
THE 12Z ECMWF...AND GFS ENSEMBLE POPS ARE NOT SHOWING MUCH. THE
12Z GFS IS THE ONLY MODEL TO SHOW SOME A CHANCE BUT THIS A LITTLE
CLOSE BEHIND THE MONDAY SYSTEM IN A SPLIT FLOW. TEMPS BACK TO NEAR
OR ABOVE NORMAL NEXT WEEK.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/JPR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
256 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PRIMARY CHALLENGE IS WIND CHILL VALUES AND ASSOCIATED HEADLINES
THIS MORNING AND AGAIN EARLY SATURDAY. WITH NO PRECIPITATION
THROUGH THE WEEKEND...TEMPERATURES WILL BE THE MAIN FOCUS
THEREAFTER. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND WILL USE A
MODEL BLEND FOR THIS FORECAST PACKAGE.
08 UTC OBSERVATIONS ALREADY SHOWING WIND CHILL VALUES IN THE 30 TO
35 BELOW RANGE ALONG AND NORTH OF THE HIGHWAY TWO CORRIDOR. RUC 925
HPA TEMPERATURES DROP TO -25 C BY 12 UTC THIS MORNING ACROSS MUCH
OF THE NORTHERN FORECAST AREA...SO AIR TEMPERATURES STILL EXPECTED
TO DROP ANOTHER 5 TO 8 DEGREES THIS MORNING BEFORE RECOVERING.
SURFACE PRESSURE GRADIENT DOES NOT WEAKEN UNTIL LATER IN THE
DAY...SO NORTH WINDS FROM 10 TO 20 MPH WILL CONTINUE THROUGH AT
LEAST MID-MORNING. ALL THIS TO SAY...WILL ISSUE AN EXTREME COLD
WARNING FOR THE NORTHERN HALF OF THE FORECAST AREA FROM 09 UTC TO
16 UTC THIS MORNING WITH WIND CHILL VALUES IN THE 30 TO 40 BELOW
RANGE.
FOR THE REST OF THE DAY...EXPECT MOSTLY SUNNY CONDITIONS. WINDS
WILL WEAKEN A BIT THIS AFTERNOON...BUT TEMPERATURES WILL BE SLOW
TO RISE WITH AFTERNOON HIGHS IN THE SINGLE DIGITS ABOVE ZERO. SOME
PLACES WITH SNOW COVER WILL LIKELY STRUGGLE TO BREAK THE ZERO
MARK.
ATTENTION THEN TURNS TO SATURDAY MORNING. AIR TEMPERATURES LOOK TO
BE SIMILAR TO THIS MORNING (-10 TO -15 F)...BUT WITH A WEAKENING
PRESSURE GRADIENT AS CENTER OF SURFACE HIGH MOVES ACROSS THE
CENTRAL DAKOTAS...NORTHWEST WIND SHOULD STAY IN THE 5 TO 10 MPH
RANGE. WIND CHILL VALUES APPROACH 30 BELOW IN SPOTS...BUT DOES NOT
APPEAR TO BE AS WIDESPREAD OR QUITE AS COLD AS THIS MORNING. WILL
HOLD OFF ON ANY EXTREME COLD PRODUCTS FOR NOW...BUT SOMETHING THE
DAY SHIFT WILL NEED TO RE-EVALUATE.
SURFACE HIGH PRESSURE CONTINUES ACROSS THE NATION/S MID-SECTION
THROUGH THE WEEKEND WITH A GRADUAL WARMING TREND...SO THAT BY
SUNDAY AFTERNOON HIGHS CLIMB BACK INTO THE LOWER TO MID 20S. DO
NOT FORESEE ANY WIND CHILL PROBLEMS SUNDAY MORNING WITH LOWS IN
THE SINGLE DIGITS ABOVE OR BELOW ZERO AND RELATIVELY LIGHT WIND.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND PLACEMENT OF MINOR
SHORTWAVES MOVING THROUGH DURING THE PERIOD. ALL DETERMINISTIC
RUNS TAKE THE SHORTWAVE ON MONDAY FURTHER SOUTH SO WE STAY DRY. A
MORE SIGNIFICANT SHORTWAVE WILL DIG INTO MANITOBA BY WEDNESDAY AND
INTO THE PLAINS/UPPER MIDWEST ON THURSDAY...ALTHOUGH THERE ARE
STILL QUITE A FEW RUN TO RUN AND INTER-MODEL DIFFERENCES IN
PLACE. ECMWF HAS A SYSTEM COMING THROUGH THE NORTHERN PLAINS ON
FRIDAY AND DROPPING SOME PRECIP...ALTHOUGH WILL HAVE TO KEEP AN
EYE ON IT AS THAT SOLUTION SEEMS TO BE WETTER THAN THE OTHER
DETERMINISTIC MODELS AND MOST ENSEMBLE MEMBERS. TEMPS WILL
CONTINUE TO BE ABOVE SEASONAL AVERAGES.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE AT ALL TAF AIRFIELDS THE NEXT 24
HOURS. GUSTY NORTHERLY WIND EARLY THIS MORNING WILL GRADUALLY
DECREASE THROUGH THE DAY AS SURFACE HIGH PRESSURE BUILDS ACROSS
THE REGION.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...EXTREME COLD WARNING UNTIL 10 AM CST THIS MORNING FOR NDZ006>008-
014>016-024-026>030-054.
MN...EXTREME COLD WARNING UNTIL 10 AM CST THIS MORNING FOR MNZ001-002-
004>009-013>017-022-023.
&&
$$
ROGERS/JR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
948 PM MST THU FEB 9 2012
.AVIATION...06Z TAF FORECASTS
MVFR CIGS ACROSS NORTHWESTERN AND CENTRAL SOUTH DAKOTA WILL
CONTINUE TO BACK INTO SOUTHWESTERN SOUTH DAKOTA AND NORTHEASTERN
WYOMING OVERNIGHT. LIGHT SNOW OR FLURRIES ARE ALSO EXPECTED TO
DEVELOP ACROSS PARTS OF NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA THROUGH EARLY FRIDAY MORNING. ALONG WITH MVFR CIGS...THE
SNOWFALL WILL RESULT IN AREAS OF MVFR VSBY WITH LOCALIZED IFR
CONDITIONS POSSIBLE...ESPECIALLY ALONG THE FOOTHILLS OF THE BLACK
HILLS.
&&
.PREV DISCUSSION... /ISSUED 513 PM MST THU FEB 9 2012/
DISCUSSION...A LARGE HUDSON BAY LOW WILL DOMINATE OUR WEATHER
THROUGH MUCH OF THE WEEKEND. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE...WITH A SUBSTANTIAL LOW-LEVEL TEMPERATURE GRADIENT ACROSS THE
CWA. THE COLD AIR AND BAROCLINIC ZONE WILL HELP TO SQUEEZE OUT THE
LIMITED MOISTURE...WITH SOME SPOTS IN NERN WY SEEING A FEW INCHES OF
ACCUMULATION.
UPPER JETS KISS OVER CWA TONIGHT AND INTENSIFY SLIGHTLY. THIS IS
FOLLOWED BY AN INFLUX OF COLDER AIR AND EVENTUALLY AN UPPER-LEVEL
TROUGH PASSAGE FRIDAY NIGHT AND SATURDAY MORNING. A STRONG...COLD
SURFACE HIGH PRESSURE ALSO WILL MOVE SOUTH ACROSS THE DAKOTAS ON
SATURDAY...BEHIND THE UPPER WAVE. AFTER THAT THE FLOW ALOFT BECOMES
WEAK...AND THUS AMENABLE TO SUBSTANTIAL LOW CLOUDS AND POSSIBLY SOME
FOG LATE SATURDAY THROUGH SUNDAY MRNG. LOW FROUDE FLOW THROUGH THE
PERIOD WILL PRECLUDE UPSLOPE SNOWS...BUT LOCAL ENHANCEMENT MAY OCCUR
IN THE NRN FOOTHILLS.
AN INITIAL SHOT OF LIGHT SNOW IS EXPECTED TONIGHT WITH THE LEADING
EDGE OF THE ARCTIC AIR...ESPECIALLY OVER NWRN THROUGH CNTRL SD. EVEN
THOUGH MOST MODELS HAVE NO INDICATION OF QPF...UPSTREAM OBS AND THE
HRRR AND RUC DO SUGGEST LIGHT SNOW SHOWERS MAY EVEN LINGER PAST 06Z
OVER MUCH OF THE SD PLAINS. OTHERWISE...THE BEST FORCING FOR UPWARD
MOTION WILL BE OVER NERN WY AND FAR SWRN SD FRIDAY AND FRIDAY NIGHT
AS TWO MORE JETS INTERACT. FRONTOGENESIS ALSO WILL BE ACTIVE ALONG
THE BAROCLINIC ZONE OVER NERN WY...AND THUS EXPECT A FEW INCHES OF
SNOWFALL. THE BAROCLINIC ZONE WILL BECOME SOMEWHAT DIFFUSE BY EARLY
SUNDAY...BUT IT STILL WILL RESIDE OVER THE SWRN CWA. THIS MAY
PROVIDE AN ADDITIONAL FOCUS FOR SNOW ON SUNDAY AS AN UPPER TROUGH
MOVES OVER THE FOUR CORNERS REGION.
LATEST MOS GUIDANCE HAS TRENDED COLDER WITH LOWS THE NEXT TWO DAYS.
WHILE THE TEMPS HAVE BEEN NUDGED LOWER...HAVE NOT GONE AS COLD AS
MOS...ESPECIALLY WHERE CLOUD COVER IS EXPECTED.
EXTENDED...UPPER LEVEL FLOW REMAINS NORTHWESTERLY OVER THE NORTHERN
PLAINS FOR EARLY NEXT WEEK. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW
POOR AGREEMENT ON TIMING AND PLACEMENT OF SEVERAL WEAK SHORTWAVES
THAT CROSS THE AREA. REGARDLESS...ATMOSPHERE REMAINS FAIRLY DRY WITH
THIS REGIME. WILL CONTINUE WITH A DRY FORECAST. TEMPERATURES IN THIS
TYPE OF FLOW SHOULD REMAIN NEAR AVERAGE.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
252 AM CST FRI FEB 10 2012
.VERY SHORT TERM...TODAY AND TONIGHT.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE KENOSHA AREA AROUND NOON.
A MID LEVEL SHORTWAVE WILL DROP SOUTHEAST AND EXTEND ACROSS EASTERN
LAKE SUPERIOR TO FAR SOUTHERN MINNESOTA BY NOON AND PUSH ACROSS
SOUTHEAST WISCONSIN EARLY THIS AFTERNOON. THIS IS SLOWING THE
SOUTHWARD PROGRESSION OF THE FRONT AND ALSO CAUSING WEAK UPWARD
MOTION TO CONTINUE AFTER THE FRONTAL PASSAGE. FORECAST SOUNDINGS
SHOW MOISTURE EXTENDING FROM THE LOW LEVELS THROUGHOUT THE MID
LEVELS. MID LEVELS THEN DRY BEHIND THE 500 MB TROUGH AXIS. AS THIS
HAPPENS LOW LEVEL LAPSE RATES INCREASE TO ALMOST 9 C/KM FROM THE
SURFACE TO 850 MB. THEREFORE EXPECT AN INITIAL SNOW SHOWER
POTENTIAL WITH THE FRONT...BUT SOME LIGHT SNOW SHOWERS/FLURRIES WILL
CONTINUE ACROSS SOUTH CENTRAL WISCONSIN THIS AFTERNOON AND ACROSS
SOUTHEAST WISCONSIN INTO THE EARLY EVENING.
NEXT PROBLEM IS INITIAL LAKE ENHANCEMENT BEHIND THE FRONT. NAM
FORECAST SOUNDINGS GENERATE LAKE ENHANCEMENT WITH AROUND 200 J/KG
OF CAPE EARLY THIS AFTERNOON AND AROUND 300 J/KG LATE THIS AFTERNOON
AND 400 J/KG EARLY THIS EVENING. DELTA T VALUES ARE MARGINAL THIS
AFTERNOON BUT JUMP TO MODERATE THIS EVENING OF -17 C. NAM SOUNDING
INDICATE THAT BY THE TIME THIS HAPPENS WINDS BECOME NORTH ACROSS
MUCH OF THE LOW LEVELS EXCEPT NORTHEAST IN A NARROW LAYER AROUND 4
THSD FT. RUC SOUNDINGS ARE MORE FAVORABLE WITH NNE OR NE WINDS FROM
JUST ABOVE THE SURFACE TO ALMOST 7 THSD FT.
WILL HOLD OFF ON ANY HEADLINES DUE TO THE UNCERTAINTY...BUT WILL
BUMP UP THE SNOW AMOUNTS NEAR THE LAKE.
AFTER MIDNIGHT THE 500 MB TROUGH REACHES LOWER MICHIGAN...AND THE
SOUNDINGS NEAR LAKE MICHIGAN SHOW A PRONOUNCED DRYING ABOVE
3 THSD FT.
.SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT.
SPRAWLING...SLOW MOVING HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS
TONIGHT AND SATURDAY AS COLD AIR SETTLES OVER THE REGION. CORE OF
COLDEST AIR WITH 85H TEMPS AROUND -18C SHIFTS SLOWLY EWD ON
SAT...CONTINUING ON SUN AS THE LOW LEVEL WINDS BEGIN TO BACK MORE
NORTHWEST. NEVERTHELESS...DESPITE SUNSHINE DO NOT WANT TO WARM TEMPS
TOO FAST AS BLUSTERY NORTHWEST WINDS WL CONTINUE ON SAT AT THE
SFC...AND SOME AREAS WL LIKELY HAVE A FRESH LIGHT SNOW COVER. MAY BE
ABLE TO MIX TO AROUND 925H BOTH DAYS. HENCE DESPITE COLD BIAS DUE
TO PERSISTENT LACK OF SNOW...WL KEEP HIGHS IN THE 15 TO 20 RANGE
MOST AREAS SAT...AND IN MID-UPR 20S SUN. BLUSTERY NORTHWEST WINDS
OF 15 TO 25KTS WL ADD A STRONG CHILL TO THE AIR ON SAT. WIND CHILLS
WILL DROP TO BTWN 5 AND 15 BLO ZERO EARLY SAT MRNG AND AGAIN LATE
SAT NGT/EARLY SUN MRNG.
PERIOD OF MID-HIGH LEVEL CLOUDS ASSOCD WITH SURGE OF WARM AIR
ADVECTION MAY BRUSH PORTIONS OF SRN WI SAT NGT...BUT MAJORITY OF
CLOUDS REMAIN NORTH.
.LONG TERM...MONDAY THROUGH THURSDAY.
EXTENDED GUIDANCE REMAINS IN REASONABLE AGREEMENT THROUGH EARLY
PERIODS. INCREASING SOUTHERLY WINDS ON THE BACKSIDE OF THE LARGE
HIGH PRESSURE AREA ALLOW MOISTURE TO INCREASE TO AROUND 0.4 INCH BY
LATER MONDAY. STRONGEST TEMP/MOISTURE ADVECTION HOWEVER REMAINS TO
THE SOUTH OF WI...HOWEVER ECMWF...GFS AND GEM-NHEM DO INCREASE
MOISTURE TO AT LEAST 10K FEET. ALTHOUGH FORCING REMAINS WEAK AS MID
LEVEL SHORT WAVE MOVES THROUGH MONDAY NIGHT...CONDENSATION PRESSURE
DEFICITS DECREASE TO LESS THAN 10MB ON MONDAY WITH WEAK ISENTROPIC
OMEGA. WITH SLR AROUND 15 TO 1...POSSIBLE FOR AN INCH OR TWO OF
SNOW MONDAY INTO MONDAY NIGHT. ENOUGH CONSISTENCY AND AGREEMENT TO
BUMP UP POPS TO LIKELY OVER MORE OF SRN WI MON AFTN CLOSER TO
STRONGER LOW LEVEL WEAK FORECING...AND IN THE SOUTHEAST MON NGT.
MID LEVEL WEAK WAVE STILL EXPECTED TO SLIDE OFF TO THE EAST BY
TUESDAY... HOWEVER PROGRESS HAS SLOWED A BIT AS SECONDARY WEAK WAVE
MOVES FROM THE UPPER MIDWEST INTO THE CENTRAL MS VALLEY. WL
CONTINUE DRYING TREND INTO TUE...BUT KEEP SCHC POPS IN THE FAR
SOUTHEAST TO REFLECT SLOWER MOVEMENT.
SEVERAL DAYS AGO...THOUGHT WE WERE HEADING TO A MORE UNSETTLED
PERIOD FOR LATER NEXT WEEK...AS MULTIPLE PIECES OF SHORT WAVE ENERGY
WERE EJECTED FROM PERSISTENT NRN PACIFIC LONG WAVE TROUGH INTO
CENTRAL CONUS. HOWEVER LAST DAY OR TWO...TREND HAS BEEN TOWARD
RETURN OF SPLIT FLOW ACROSS CONUS...WITH SRN STREAM REMAINING MORE
ACTIVE FROM TUE INTO THU. ECWMF FIRST TO PICK UP ON DRIER NRN
STREAM SIGNAL...AND LAST SEVERAL RUNS OF GFS NOW BACKING OFF ON
UNSETTLED MID-WEEK WX FOR UPPER MIDWEST. HPC ALSO TRENDING TOWARD
DRIER SOLUTION...FAVORING ECMWF OR ECMWF BLEND. FOR NOW...WL KEEP
POPS VERY LOW FOR LATE PDS WITH LOW CONFIDENCE. END RESULT...PALTRY
WINTER CONDITIONS TO CONTINUE.
&&
.AVIATION /12Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE BROUGHT MVFR STRATUS
ACROSS THE FORECAST AREA AND WILL PERSIST EARLY THIS MORNING.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE FAR SOUTHEAST TIP AROUND NOON. MAINLY CIGS
EXPECTED BEHIND THE FRONT ALONG WITH MVFR VSBYS IN SNOW SHOWERS WITH
SOME IFR VSBYS IN THE HEAVIER SNOW SHOWERS. APPEARS LAKE
ENHANCEMENT TO DEVELOP LATE THIS MORNING TOWARD SHEBOYGAN AND
ACROSS SOUTHEAST WISCONSIN FROM MILWAUKEE SOUTH THIS AFTERNOON.
OCCASIONAL IFR VSBYS EXPECTED WITH THIS SNOW. BY EVENING A LAKE
EFFECT SNOW BAND SHOULD SET UP MAINLY OVER WESTERN LAKE MICHIGAN AND
AFFECT AREAS MAINLY SOUTH OF THE ILLINOIS BORDER...BUT THERE IS A
POSSIBILITY OF SOME OF THIS SNOW AFFECTING THE SHORELINE AREAS
MAINLY SOUTH OF MILWAUKEE.
&&
.MARINE...
WINDS MAY BRIEFLY DROP BELOW SMALL CRAFT CRITERIA EARLY THIS MORNING
JUST AHEAD OF A TROUGH OF LOW PRESSURE EXTENDING ACROSS NORTHERN
LAKE MICHIGAN. AS AN ASSOCIATED STRONG COLD FRONT DROPS SOUTH
ACROSS SOUTHERN LAKE MICHIGAN LATER THIS MORNING WINDS WILL BECOME
NORTH AND INCREASE DRAMATICALLY. A FEW WIND GUSTS MAY APPROACH GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS.
DUE TO THE COLDER AIR WAVES EXPECTED TO INCREASE RAPIDLY BEHIND THE
FRONT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL OF THE SHORE
AREAS INTO SATURDAY AFTERNOON.
&&
.CONFIDENCE...
TODAY AND TONIGHT...MEDIUM.
SATURDAY THROUGH SUNDAY NIGHT...MEDIUM TO HIGH.
MONDAY AND MONDAY NIGHT...MEDIUM TO HIGH.
TUESDAY...MEDIUM.
WEDNESDAY AND THURSDAY...LOW TO MEDIUM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CST SATURDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
SHORT TERM/LONG TERM...MBK
VERY SHORT TERM/AVIATION/MARINE...SJH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
237 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
237 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUDS/TEMPERATURES/PRECIPITATION
TODAY...THEN WIND CHILLS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S INTO THE NORTHWEST
TERRITORIES OF CANADA...AND TROUGHING FROM THE DAKOTAS INTO QUEBEC.
WITHIN THIS TROUGH...A SHORTWAVE WAS PRESENT FROM NORTH DAKOTA INTO
NORTHERN MINNESOTA. A REMNANT STREAM OF PACIFIC MOISTURE AND DPVA
AHEAD OF THE SHORTWAVE HELPING TO PRODUCE A BAND OF MID-CLOUDS FROM
NORTHEAST SOUTH DAKOTA TO LAKE SUPERIOR. BELOW THIS...AN AREA OF
STRATUS RESULTING FROM MOISTURE TRAPPED IN A COLD FRONTAL INVERSION
WAS PRESENT FROM NORTHWEST IOWA INTO NORTHERN WISCONSIN. SOME LIGHT
SNOW WAS ALSO FALLING OUT OF THIS STRATUS OVER THE NORTH HALF OF
WISCONSIN...DUE TO THE PRESENCE OF LOW LEVEL FRONTOGENESIS PER RUC
ANALYSIS. THE THERMAL CONTRAST OF THE FRONTOGENESIS COULD BE SEEN
FROM A 00Z 850MB SOUNDING PLOT...NOTED BY A -6C TEMP AT MPX AND -17C
AT INL. AT THE SURFACE...A COLD FRONTAL BOUNDARY STRETCHED FROM
NORTHERN LAKE MICHIGAN SOUTHWEST TO DES MOINES...WHILE A 1041MB
ARCTIC HIGH PRESSURE AREA WAS OVER CENTRAL SASKATCHEWAN.
TODAY AND TONIGHT...SHORTWAVE OVER NORTH DAKOTA AND NORTHERN
MINNESOTA IS PROGGED TO MOVE THROUGH THE FORECAST AREA BETWEEN
15-21Z TODAY...ALLOWING THE ARCTIC HIGH PRESSURE AREA OVER
SASKATCHEWAN TO DROP SOUTH IN ITS WAKE. BY 12Z SATURDAY...THE HIGH
SHOULD BE SITUATED IN THE DAKOTAS. WITH THE HIGH WELL OFF TO THE
WEST...ANTICIPATING BLUSTERY CONDITIONS ACROSS MUCH OF THE FORECAST
AREA THROUGH TONIGHT. WIND DIRECTION IS A LITTLE INTERESTING. DUE TO
THE TRACK OF THE DEPARTING COLD FRONT...THE SURFACE-850MB WINDS ARE
MORE NORTH TO NORTHEAST TODAY...THEN SWITCHES TO THE NORTHWEST
TONIGHT. THIS WIND DIRECTION PATTERN MEANS THAT LOW LEVEL MOISTURE/
CLOUDS MAY GET STUCK OVER THE FORECAST AREA MORE TODAY...AIDED BY
MOISTENING OFF LAKE SUPERIOR. ONCE THE WINDS GO NORTHWEST...THE DRY
ARCTIC AIR CAN FLOW IN AND CLEAR OUT THE STRATUS. ONE CAVEAT IS THAT
RIGHT NOW THE AIR OVER NORTHERN ONTARIO IS DRIER THAN THE MODELS
SUGGEST. WILL HAVE TO WATCH TO SEE THROUGH THE DAY TODAY ON HOW MUCH
OF THIS DRIER AIR OVER NORTHERN ONTARIO ADVECTS SOUTH. NEXT CONCERN
IS THE PRECIPITATION. THE 10.00Z NAM AND HRRR RUNS HAVE SHOWN SOME
VERY LIGHT SNOW/FLURRIES...MOSTLY ALONG AND EAST OF THE MISSISSIPPI
RIVER THIS MORNING. LOW LEVEL FRONTOGENETICAL FORCING APPEARS TO BE
THE MAIN PRODUCTION FEATURE...WITH THE SNOW MORE LIKELY TO OCCUR DUE
TO THE STRATUS EVENTUALLY INTERSECTING THE DENDRITIC GROWTH ZONE AS
THE COLDER AIR MOVES IN. A FEW TENTHS SEEM POSSIBLE. HAVE LEFT SOME
FLURRIES IN FOR THE AFTERNOON TOO...BUT THINK THE BULK OF ANY
ACCUMULATING TYPE SNOW WOULD BE OFF TO THE EAST WHERE THE LOW LEVEL
FRONTOGENESIS IS EXPECTED. FINAL CONCERN IS TEMPERATURES. 850MB
TEMPS REALLY DROP TODAY...FROM -8C SOUTHEAST TO -16C NORTHWEST
ACROSS THE FORECAST AREA AT 12Z...TO BASICALLY AROUND -20C AT 00Z.
WITH STRATUS IN PLACE AND FALLING 850MB TEMPS...LOOK FOR SURFACE
TEMPERATURES TO SLOWLY FALL THROUGH THE DAY...DROPPING WIND CHILLS.
TONIGHT...THE TEMPERATURE FALL WILL MAINLY BE A RESULT OF ADVECTION
DUE TO BLUSTERY CONDITIONS KEEPING THE BOUNDARY LAYER MIXED.
STILL...LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO SUGGESTED BY
GUIDANCE AND THE PREVIOUS FORECAST SEEM REASONABLE. MAY NEED WIND
CHILL ADVISORIES FOR PORTIONS OF THE AREA VERY LATE...MOST LIKELY
TAYLOR AND CLARK ZONES. GIVEN SUCH A SMALL AREA AND MARGINAL WIND
CHILLS AT THAT...HELD OFF ON ISSUING AN ADVISORY AT THIS TIME.
SATURDAY THROUGH SUNDAY NIGHT...FAIRLY QUIET PERIOD EXPECTED AS
500MB HEIGHTS GRADUALLY BUILD. ARCTIC HIGH PRESSURE AREA NEVER
BUILDS OVER THE AREA...TRACKING MORE SOUTH TO THE LOWER MISSISSIPPI
RIVER VALLEY BY MID-DAY SUNDAY. THIS TRACK SHOULD KEEP CONDITIONS
FROM DECOUPLING SATURDAY NIGHT...PREVENTING ANY DRAMATIC TEMPERATURE
FALL FROM RADIATIONAL COOLING. ONLY REAL CONCERN IS SUNDAY NIGHT.
DURING THIS PERIOD...MODELS HAVE UPPER TROUGHING CROSSING THE
WESTERN U.S. TOWARDS THE PLAINS WITH RIDGING BUILDING UP TOWARDS THE
FORECAST AREA. 10.00Z NAM HINTS THAT A FEW WEAK SHORTWAVES MAY COME
OUT OF THE TROUGH AND APPROACH THE AREA BY 12Z MONDAY. WITH THESE
SHORTWAVES...THE NAM BRINGS SOME PRECIPITATION INTO NORTHEAST IOWA
AFTER MIDNIGHT SUNDAY NIGHT. BY FAR THE NAM IS THE FASTEST OF ANY
GUIDANCE AND THEREFORE FOR NOW HAS BEEN DISCOUNTED. HAVE DRIED OUT
ALMOST ALL OF THE FORECAST AREA AS A RESULT...THOUGH LEFT A 20
PERCENT CHANCE FOR CHARLES CITY TO OELWEIN IA JUST IN CASE THE
FASTER SCENARIO WOULD PLAY OUT. AN INCREASE IN MID TO UPPER LEVEL
CLOUD COVER IS LIKELY SUNDAY NIGHT...HOWEVER. A GRADUAL WARMING
TREND IS ANTICIPATED THROUGH THE WEEKEND AS THE ARCTIC HIGH SLOWLY
MODIFIES...HELPED TOO BY THE GENERAL LACK OF SNOW COVER FROM THE
DAKOTAS INTO THE UPPER MISSISSIPPI RIVER VALLEY. 850MB TEMPS CLIMB
TO -12C BY 00Z SUNDAY AND -6C BY 00Z MONDAY. WITH THE WARMING 850MB
TEMPS...HIGHS SHOULD CLIMB INTO THE 15 TO 20F RANGE ON SATURDAY AND
25 TO 30F RANGE ON SUNDAY.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
237 AM CST FRI FEB 10 2012
OVERALL PATTERN LOOKS FAIRLY BENIGN THROUGHOUT MUCH OF THE LONG TERM
PERIOD SUGGESTED BY THE 10.00Z ECMWF/CANADIAN/GFS/UKMET AND GFS
ENSEMBLES. A SPLIT FLOW SCENARIO IS FORECAST BY ALL OF THESE
MODELS...WITH THE NORTHERN STREAM FEATURING ZONAL TO WEAK TROUGHING
ACROSS SOUTHERN CANADA...AND A SOUTHERN STREAM FEATURING TROUGHING
IN THE SOUTHWEST U.S. TO ZONAL TO SLIGHT RIDGING OVER THE
SOUTHEASTERN U.S.. THIS MEANS MOST OF THE PRECIPITATION ACTION ENDS
UP STAYING TO THE NORTH AND SOUTH OF THE FORECAST AREA WITH NO COLD
SHOTS IN THE OFFERING. THE ONLY EXCEPTION TO THE PRECIPITATION IS
MONDAY INTO MONDAY EVENING...DUE TO THE COMBINATION OF WEAK LOW
LEVEL MOISTURE TRANSPORT AND WEAK SHORTWAVES PROGGED TO MOVE THROUGH
THE AREA. THESE SHORTWAVES ORIGINATING OUT OF THE TROUGHING MOVING
INTO THE PLAINS SUNDAY NIGHT. THERE REMAINS STRONG CONTINUITY FOR
PRECIPITATION SOUTH OF I-90...SO MAINTAINED 50-60 PERCENT CHANCES
THERE FOR MONDAY. PRECIPITATION CHANCES TAPER OFF HEADING NORTH AS
CONFIDENCE IN MOISTURE AVAILABILITY IS LOWER. DOES NOT LOOK LIKE
ANYTHING BIG IN TERMS OF SNOW ACCUMULATION GIVEN THE WEAK
FORCING...PERHAPS AROUND AN INCH. A LITTLE FARTHER OUT...THE 10.00Z
ECMWF/CANADIAN BOTH HINT AT SOME SHORTWAVE TROUGHS CROSSING THE AREA
WEDNESDAY NIGHT INTO THURSDAY...ORIGNIATING FROM SOUTHERN EXTENSIONS
OFF THE NORTHERN STREAM. WITH LACK OF MOISTURE...KEPT THE CONSENSUS
15 TO 20 PERCENT CHANCES. WOULD NOT BE SURPRISED IF IT ENDS UP DRY.
TEMPERATURES THROUGHOUT THE LONG TERM PERIOD SHOULD END UP AT OR
ABOVE NORMAL DUE TO ALL THE COLD AIR BEING LOCKED BACK UP OVER
NORTHERN CANADA. IN FACT...IT APPEARS THE GENERAL ABOVE NORMAL
CONDITIONS WILL PERSIST AT LEAST FOR THE NEXT ONE TO TWO WEEKS...IF
NOT LONGER...PER THE CFS VERSION 2 FORECASTS.
&&
.AVIATION...THROUGH 06Z SATURDAY
1110 PM CST THU FEB 9 2012
AN ARCTIC FRONT WILL CROSS THROUGH BOTH TAF SITES BETWEEN 06 AND 10Z
AND WINDS TAKE A TURN TO THE NORTHWEST...BECOMING GUSTY. SNOW
SHOWERS STILL LOOK POSSIBLE...AND CURRENT RADAR RETURNS SHOW BANDS
OF LIGHT SNOW MOVING SOUTHEAST ACROSS EASTERN MINNESOTA/NORTHWEST
WISCONSIN. SOME VSBY RESTRICTIONS IN THIS SNOW...BUT IF IT DOES
MANIFEST AT KRST/KLSE...DON/T EXPECT ANY REDUCTIONS BELOW 5SM AT
THIS TIME.
MOST FORECAST GUIDANCE CONTINUES TO SUGGEST A BROKEN TO OVERCAST
MVFR CEILINGS THROUGH MID DAY FRIDAY...GRADUALLY BECOMING SKC DURING
THE AFTERNOON. HOWEVER...LATEST NAM12/RUC13 850 MB RH AND WIND
FIELDS SHOW NORTH-NORTHEAST FLOW OFF LAKE SUPERIOR. THIS COULD LEAD
TO A LOBE OF LAKE ENHANCED STRATUS MOVING SOUTHWEST OVER KLSE AND
POSSIBLY KRST. CONFIDENCE IS NOT HIGH IN WHICH WAY THIS WILL
GO...BUT WILL LEAN ON DELAYING THE CLEARING UNTIL THE LATE
AFTERNOON/EVENING. OBVIOUSLY...TRENDS WILL BE MONITORED...AND IF
ADDITIONAL STRATUS DOES NOT DEVELOP...UPDATES FOR EARLIER CLEARING
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 AM CST FRI FEB 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION....TAYLOR/RIECK
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
ISSUED BY NATIONAL WEATHER SERVICE COLUMBIA SC
947 AM EST FRI FEB 10 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SMOKE...MOST LIKELY FROM PRESCRIBED BURN ACTIVITY OVER BERKELEY
COUNTY...HAS REACHED AS FAR WEST AS SUMMERVILLE. HAVE INCLUDED
AREAS OF SMOKE IN THE MONCKS CORNER-SUMMERVILLE CORRIDOR THROUGH
MID-MORNING.
10/11Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 MB AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD AIR ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW OVERNIGHT...
CONTRIBUTING TO WIND CHILL VALUES IN THE 12-18 DEGREE RANGE.
RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH
SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
CIGS WILL TEETER ALONG THE MVFR/VFR THRESHOLD THROUGH MID-MORNING
BEFORE FINALLY DROPPING MORE SOLIDLY MVFR. STILL SEEING LOTS OF
TIMING/INTENSITY AND PLACEMENT ISSUES FOR ANY SHOWER ACTIVITY
TODAY. WHILE SHOWERS WILL LIKELY BE AROUND...ESPECIALLY THIS
AFTERNOON...CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO JUSTIFY
A MENTION AT EITHER TERMINAL. CONDITIONS WILL IMPROVE THIS EVENING
AS A COLD FRONT PUSHES OFFSHORE.
EXTENDED AVIATION OUTLOOK...GUSTY WINDS WILL BECOME A CONCERN
SATURDAY WITH LLWS POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD
IMPACT THE TERMINALS AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM
MOVES THROUGH THE AREA.
&&
.MARINE...
THIS AFTERNOON...THE AREA CONTINUES TO BE POSITIONED NEAR A
SHARPENING COASTAL TROUGH ALONG THE FLORIDA EAST COAST. THIS HAS
BROUGHT GENERALLY NORTHEAST WINDS WITH SPEEDS BELOW 15 KT. STILL
EXPECTING NORTHEAST WINDS TO REMAIN IN CONTROL INTO THE EARLY
AFTERNOON HOURS BEFORE VEERING MORE SOUTHERLY LATE THIS AFTERNOON AS
THE COASTAL TROUGH BREAKS DOWN AND A COLD FRONT APPROACHES FROM THE
WEST. BOTH WINDS AND SEAS WILL REMAIN WELL BELOW SMALL CRAFT
ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
656 AM EST FRI FEB 10 2012
...ARCTIC AIR POISED TO MAKE A RETURN TO THE LOWCOUNTRY AND
COASTAL EMPIRE THIS WEEKEND...
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SMOKE...MOST LIKELY FROM PRESCRIBED BURN ACTIVITY OVER BERKELEY
COUNTY...HAS REACHED AS FAR WEST AS SUMMERVILLE. HAVE INCLUDED
AREAS OF SMOKE IN THE MONCKS CORNER-SUMMERVILLE CORRIDOR THROUGH
MID-MORNING.
10/11Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 MB AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD AIR ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW OVERNIGHT...
CONTRIBUTING TO WIND CHILL VALUES IN THE 12-18 DEGREE RANGE.
RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH
SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
CIGS WILL TEETER ALONG THE MVFR/VFR THRESHOLD THROUGH MID-MORNING
BEFORE FINALLY DROPPING MORE SOLIDLY MVFR. STILL SEEING LOTS OF
TIMING/INTENSITY AND PLACEMENT ISSUES FOR ANY SHOWER ACTIVITY
TODAY. WHILE SHOWERS WILL LIKELY BE AROUND...ESPECIALLY THIS
AFTERNOON...CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO JUSTIFY
A MENTION AT EITHER TERMINAL. CONDITIONS WILL IMPROVE THIS EVENING
AS A COLD FRONT PUSHES OFFSHORE.
EXTENDED AVIATION OUTLOOK...GUSTY WINDS WILL BECOME A CONCERN
SATURDAY WITH LLWS POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD
IMPACT THE TERMINALS AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM
MOVES THROUGH THE AREA.
&&
.MARINE...
TODAY...THE REGION IS POSITIONED NORTH OF A SHARPENING COASTAL
TROUGH ALONG THE FLORIDA EAST COAST THIS MORNING. THIS IS YIELDING
A SOLID NORTHEAST WIND REGIME WITH SPEEDS GENERALLY BELOW 15 KT.
NORTHEAST WINDS WILL DOMINATE FOR MUCH OF THE DAY BEFORE VEERING
MORE SOUTHERLY THIS AFTERNOON AS THE COASTAL TROUGH BREAKS DOWN
AND A COLD FRONT APPROACHES FROM THE WEST. BOTH WINDS AND SEAS
WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CLIMATE...
RECORD LOWS FOR SUNDAY FEBRUARY 12...
CHARLESTON AIRPORT.... 12/1973
DOWNTOWN CHARLESTON... 22/1955
SAVANNAH AIRPORT...... 19/1973
RECORD LOWS FOR MONDAY FEBRUARY 13...
CHARLESTON AIRPORT.... 22/1955
DOWNTOWN CHARLESTON... 9/1899
SAVANNAH AIRPORT...... 8/1899
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
642 AM EST FRI FEB 10 2012
...ARCTIC AIR POISED TO MAKE A RETURN TO THE LOWCOUNTRY AND
COASTAL EMPIRE THIS WEEKEND...
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SMOKE...MOST LIKELY FROM PRESCRIBED BURN ACTIVITY OVER BERKELEY
COUNTY...HAS REACHED AS FAR WEST AS SUMMERVILLE. HAVE INCLUDED
AREAS OF SMOKE IN THE MONCKS CORNER-SUMMERVILLE CORRIDOR THROUGH
MID-MORNING.
10/11Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 MB AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS...AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW
OVERNIGHT...CONTRIBUTING TO WIND CHILL VALUES POSSIBLY IN THE
TEENS. RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA
WITH SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
CIGS WILL TEETER ALONG THE MVFR/VFR THRESHOLD THROUGH MID-MORNING
BEFORE FINALLY DROPPING MORE SOLIDLY MVFR. STILL SEEING LOTS OF
TIMING/INTENSITY AND PLACEMENT ISSUES FOR ANY SHOWER ACTIVITY
TODAY. WHILE SHOWERS WILL LIKELY BE AROUND...ESPECIALLY THIS
AFTERNOON...CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO JUSTIFY
A MENTION AT EITHER TERMINAL. CONDITIONS WILL IMPROVE THIS EVENING
AS A COLD FRONT PUSHES OFFSHORE.
EXTENDED AVIATION OUTLOOK...GUSTY WINDS WILL BECOME A CONCERN
SATURDAY WITH LLWS POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD
IMPACT THE TERMINALS AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM
MOVES THROUGH THE AREA.
&&
.MARINE...
TODAY...THE REGION IS POSITIONED NORTH OF A SHARPENING COASTAL
TROUGH ALONG THE FLORIDA EAST COAST THIS MORNING. THIS IS YIELDING
A SOLID NORTHEAST WIND REGIME WITH SPEEDS GENERALLY BELOW 15 KT.
NORTHEAST WINDS WILL DOMINATE FOR MUCH OF THE DAY BEFORE VEERING
MORE SOUTHERLY THIS AFTERNOON AS THE COASTAL TROUGH BREAKS DOWN
AND A COLD FRONT APPROACHES FROM THE WEST. BOTH WINDS AND SEAS
WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
645 AM EST FRI FEB 10 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(346 AM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMINISH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(645 AM EST FRI FEB 10 2012)
A BAND OF SNOW WILL DROP SOUTHEAST THROUGH THE TAF SITES LEADING TO
IFR CONDITIONS BEGINNING LATER THIS MORNING AND CONTINUING INTO THE
AFTERNOON. CONDITIONS COULD TEMPORARILY GO TO LIFR THIS AFTERNOON.
WINDS WILL INCREASE LATER THIS AFTERNOON AND EVENING AND GUSTS OVER
25 KNOTS FROM THE NORTH ARE FORECASTED FOR THE TAF SITES. THE
DEEPER MOISTURE PULLS AWAY FOR LATE TONIGHT AND THAT SHOULD SHUT
DOWN MOST OF THE SNOW...BUT MVFR CLOUDS WILL PREVAIL.
&&
.MARINE...(346 AM EST FRI FEB 10 2012)
WE/LL SEE AN ABRUPT WIND SHIFT TODAY AS A STRONG COLD FRONT MOVES
THROUGH. WINDS WILL GUST FROM THE NORTH BEHIND THE FRONT TO JUST
UNDER GALE FORCE AND THEN DIMINISH OVERNIGHT. AS TEMPS FALL BELOW
FREEZING LATER THIS AFTERNOON AND TONIGHT...THE GUSTY WINDS MAY
RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THIS AFTERNOON AND EVENING FOR ALL BUT
THE NORTHERN TWO ROWS OF COUNTIES.
LM...SMALL CRAFT ADVISORY THROUGH SATURDAY.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93
LONG TERM: MJS
AVIATION: MJS
MARINE: 93
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EST FRI FEB 10 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL DEVELOP ALONG THE CAROLINA COAST
TONIGHT AS AN UPPER LEVEL DISTURBANCE CROSSES THE AREA. IN THE WAKE
OF THE LOW...A STRONG ARCTIC COLD FRONT WILL SWEEP ACROSS THE
CAROLINAS SATURDAY AFTERNOON. BEHIND THE FRONT...STRONG NORTHWEST
WINDS WILL USHER IN A MUCH COLDER AIRMASS INTO THE AREA SATURDAY
NIGHT AND SUNDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 1000 AM FRIDAY...
OVERVIEW:
SHORTWAVE ENERGY OVER MISSISSIPPI AND ALABAMA THIS MORNING WILL MOVE
ACROSS THE STATE THIS AFTERNOON AND THIS EVENING. FURTHER
UPSTREAM...A POTENT UPPER LEVEL TROUGH WILL DIG SOUTHEAST INTO THE
UPPER MIDWEST/UPPER GREAT LAKES...PROGRESSING INTO THE OHIO VALLEY
TONIGHT AND APPROACHING THE MID-ATLANTIC BY 12Z SAT. LOW-LEVEL FLOW
WILL BACK TO THE SOUTHWEST TODAY IN ADVANCE OF A SFC-850 MB TROUGH
APPROACHING THE AREA FROM THE WEST. A LOW-LEVEL TROUGH WILL
PROGRESS THROUGH THE CAROLINAS TONIGHT BEFORE MOVING OFFSHORE BY 12Z
SAT MORNING.
PRECIPITATION AND TEMPERATURES THIS AFTERNOON:
CLOUDS HAVE ADVECTED INTO THE AREA QUICKLY THIS MORNING...AND WILL
BE SPREADING TOWARD KIXA QUICKLY AS WELL TOWARD THE NOON HOUR.
CONSIDERABLE CLOUDINESS TO THE SOUTHWEST WILL RESULT IN A MOSTLY
CLOUDY TO CLOUDY SKY ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON.
MUCH OF THE GUIDANCE SUPPORTS QPF IN PARTS OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN THIS AFTERNOON...WHILE THE RUC IS DRIEST.
TOOK A CLOSE LOOK AT THE RUC FOR ITS EVIDENCE OF DRIER CONDITIONS...
AND EVEN THAT MODEL SHARPENS THE INVERTED SURFACE TROUGH NEAR THE
COAST LATE THIS AFTERNOON AS THE LEFT EXIT REGION OF A 125KT 300MB
JET SHIFTS SOUTH. IN ADDITION...UNDER AMPLE 850MB THETA-E ADVECTION
SOUTHEAST...LOW-LEVEL LIFT AND CONVERGENCE INCREASE UNDER WEAK
DIFFLUENCE ALOFT IN VICINITY OF THE JET. MODEL SOUNDINGS FROM THE
RUC...WHILE SHOWING THE LOW-LEVEL DRY AIR ON THE 12Z UPPER-AIR
ANALYSIS OVER THE CAROLINAS AND TO THE SOUTHWEST...RAPIDLY MOISTEN
PARTICULARLY BETWEEN 21Z AND 00Z. RADAR TRENDS UPSTREAM SHOW THE DRY
AIR WILL BE TOUGH TO OVERCOME...BUT ANTICIPATE ENOUGH LIFT LATE IN
THE DAY TO EDGE LATE-DAY CHANCES TO LIKELY MAINLY NEAR KMEB...
KFAY...AND KCTZ...WITH ONLY CHANCES TO ABOUT KJNX AND KGSB.
ELSEWHERE...THERE COULD BE ENOUGH MID-LEVEL MOISTURE AND LIFT FOR
SPRINKLES AS THE MID-LEVEL WAVE MOVES THROUGH THE AREA...WITH MODEL
SOUNDINGS FROM BOTH THE LATEST NAM AND RUC SUGGESTIVE OF DECENT
MOISTURE IN THE -10C TO -15C RANGE ALOFT. GIVEN THE RAPID ADVECTION
OF CLOUD COVER...NUDGED MAXES DOWN TO NEAR THE COLDEST GUIDANCE. -DJF
TONIGHT:
FORCING FOR ASCENT TONIGHT WILL BE A COMBINATION OF DPVA/HEIGHT
FALLS ASSOCIATED WITH THE UPPER LEVEL DISTURBANCE TRACKING ACROSS
THE AREA...LOW-LEVEL CONVERGENCE ASSOC/W THE ATTENDANT LOW-LEVEL
TROUGH...AND A NARROW CORRIDOR OF STRONGER WARM ADVECTION IN ADVANCE
OF THE LOW-LEVEL TROUGH. COMPARED TO YESTERDAY...THE LATEST 00Z
GUIDANCE INDICATES A RELATIVE BETTER CHANCE FOR BACKED LOW-LEVEL
FLOW (AND STRONGER WARM ADVECTION) OVER THE EASTERN CAROLINAS IN
ADVANCE OF THE APPROACHING LOW-LEVEL TROUGH BETWEEN 00-06Z TONIGHT.
HOWEVER...THE 00Z GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH
THE EVOLUTION OF THE LOW-LEVEL HEIGHT/WIND FIELDS OVER THE CENTRAL/
EASTERN CAROLINAS...AND THIS LENDS A FAIR AMOUNT OF UNCERTAINTY TO
THE PRECIP FORECAST. THE 00Z GFS/NAM SHOW ANYWHERE FROM 0.10" TO
0.50" OF RAIN EAST OF I-95...WHILE THE 00Z ECMWF SHOWS BARELY A
HUNDREDTH IN THE COASTAL PLAIN AND DRY ELSEWHERE. WITH THE ABOVE IN
MIND...HAVE MADE SOME CHANGES TO THE PREVIOUS FORECAST...CONFINING
THE HIGHEST PRECIP CHANCES (60-70%) EAST OF I-95...TAPERING TO
SLIGHT/LOW CHANCE JUST WEST OF THE HWY 1 CORRIDOR. EXPECT PRECIP
AMOUNTS OF 0.10" OR LESS...HIGHEST EAST OF I-95...ALTHOUGH LOCALLY
HIGHER AMOUNTS WILL BE POSSIBLE IF THE GFS/NAM SOLUTIONS ARE CLOSER
TO REALITY THAN THE ECMWF. WITH MOST OF THE FORCING CONFINED TO THE
MID/UPPER LEVELS IN THE NW PIEDMONT AND A DRY ANTECEDENT LOW/MID
LEVEL AIRMASS IN PLACE...HAVE OPTED TO KEEP THE FCST DRY IN THE
TRIAD...ASIDE FROM A SLIGHT CHANCE OF SPRINKLES. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM FRIDAY...
OVERVIEW:
THE AFOREMENTIONED UPPER LEVEL DISTURBANCE WILL MOVE OFFSHORE BY 12Z
SAT. HOWEVER...A POTENT/AMPLIFYING UPPER LEVEL TROUGH WILL DIG
SOUTHEAST THROUGH THE GREAT LAKES/OH VALLEY INTO THE CENTRAL
APPALACHIANS SATURDAY MORNING...INTO THE MID-ATLANTIC/CAROLINAS
SATURDAY AFT/EVE...AND OFFSHORE THE CAROLINA COAST BY 12Z SUN
MORNING. THE LOW PRESSURE SYSTEM DEVELOPING ALONG THE CAROLINA COAST
TONIGHT IS EXPECTED TO RAPIDLY INTENSIFY SAT/SAT NIGHT AS IT TRACKS
NORTHEAST OFFSHORE THE NEW ENGLAND COAST INTO THE CANADIAN
MARITIMES...WHILE STRONG (1040-1045 MB) HIGH PRESSURE PUSHES SOUTH
THROUGH THE CENTRAL PLAINS AND BUILDS EAST TOWARD THE CAROLINAS AND
MID-ATLANTIC. A STRONG ARCTIC COLD FRONT WILL BE PRESENT AT THE
LEADING EDGE OF THE SFC HIGH BUILDING INTO THE AREA...WITH THE
FRONTAL PASSAGE OCCURRING RAPIDLY DURING MID/LATE SAT AFTERNOON.
TEMPERATURES:
DIFFICULT HIGH TEMP FCST SATURDAY. HIGHS WILL BE DRIVEN PRIMARILY BY
THE TIMING OF THE ARCTIC COLD FRONTAL PASSAGE. THE 00Z GUIDANCE IS
IN GOOD AGREEMENT SHOWING FROPA BETWEEN ROUGHLY 18-21Z SAT
AFTERNOON...WITH 1000-850 MB THICKNESSES RAPIDLY PLUMMETING FROM
1300-1330 METERS (NW-SE) TO 1260-1290 METERS BY 00Z SUNDAY. EXPECT
HIGHS TO OCCUR BY ~18Z WEST OF HIGHWAY 1...WITH TEMPS RAPIDLY
FALLING DURING THE MID/LATE AFTERNOON. EAST OF HIGHWAY 1...HIGHS
WILL OCCUR JUST PRIOR TO THE FRONTAL PASSAGE BETWEEN 17-20Z...WITH
TEMPS RAPIDLY FALLING BY LATE AFTERNOON. WITH THE ABOVE IN
MIND...WILL INDICATE HIGHS RANGING FROM THE LOWER/MID 40S IN THE NW
PIEDMONT TO THE LOWER/MID 50S IN THE SE COASTAL PLAIN. LOWS SAT
NIGHT WILL BE DRIVEN BY STRONG COLD ADVECTION. WITH THICKNESSES
~1250-1260 METERS EVERYWHERE BY 12Z SUN...EXPECT LOWS RANGING FROM
THE UPPER TEENS TO LOWER 20S NW PIEDMONT TO THE LOWER/MID 20S
ELSEWHERE.
PRECIPITATION:
WITH LOW-LEVEL DRYING IN THE WAKE OF THE SURFACE LOW TRACKING
NORTHEAST AWAY FROM THE CAROLINA COAST SATURDAY MORNING AND
STRENGTHENING WESTERLY FLOW/COLD ADVECTION IN THE LOWER LEVELS...
ANTICIPATE LITTLE CHANCE FOR PRECIP ON SATURDAY. HAVING SAID
THAT...SEVERAL POSITIVE FACTORS COULD OVERCOME THE NEGATIVE AND
RESULT IN ISOLD SHOWER ACTIVITY SATURDAY AFTERNOON. ALTHOUGH
LOW-LEVEL FLOW WILL BE UNIDIRECTIONAL...STRONG PRESSURE RISES
APPROACHING FROM THE WEST AS THE SFC HIGH BUILDS TOWARD THE AREA
WILL RESULT IN LOW-LEVEL SPEED CONVERGENCE ALONG THE LEADING EDGE OF
THE FRONT. IN THE UPPER LEVELS...PRODIGIOUS DPVA/HEIGHT FALLS WILL
BE PRESENT DURING THE DAY IN ASSOC/W THE AMPLIFYING UPPER LEVEL
TROUGH DIGGING INTO THE CAROLINAS. ADDITIONALLY...STRONG LOW-LEVEL
COLD ADVECTION COMBINED WITH VERY STRONG LAYER-LIFTING ASSOC/W THE
AMPLIFYING UPPER LEVEL TROUGH WILL RESULT IN STEEPENING LOW/MID
LEVEL LAPSE RATES DURING PEAK HEATING SATURDAY...POTENTIALLY
YIELDING A SMALL AMOUNT OF SFC-BASED INSTABILITY. WITH THE ABOVE IN
MIND...AND THE FACT THAT ALL OF THIS WILL BE COMING TOGETHER DURING
OR CLOSE-TO PEAK HEATING (EXCEPT FOR THE NW PIEDMONT)...WILL
INDICATE A SLIGHT CHANCE OF SHOWERS SAT AFTERNOON ALONG AND EAST OF
HWY 1.
WIND:
STRONG PRESSURE RISES ARE EXPECTED IN THE IMMEDIATE WAKE OF THE
ARCTIC COLD FRONT SATURDAY AFTERNOON/EVENING...AS MUCH AS 6MB/3HR.
ADDITIONALLY...THE AMPLIFYING UPPER LEVEL TROUGH IS PROGGED TO DIG
SOUTHEAST INTO THE CAROLINAS COINCIDENT WITH THE STRONGEST PRESSURE
RISES...ALLOWING FOR DEEPER MIXING VIA STEEPENING OF BOTH THE LOW
AND MID-LEVEL LAPSE RATES. FCST SOUNDINGS SHOW 40-50 KT NW FLOW AS
LOW AS 925 MB SAT AFT/EVE. WITH THE ABOVE IN MIND...THERE IS AT
LEAST A POTENTIAL FOR STRONG NW WINDS SATURDAY AFTERNOON/EVENING...
BETWEEN 4 PM AND MIDNIGHT. SUSTAINED WINDS OF 20-30 MPH WITH GUSTS
UP TO 40 MPH ARE EXPECTED WITH THE STRONGEST PRESSURE RISES...WITH A
POTENTIAL FOR OCCASIONAL/SPORADIC HIGHER GUSTS. ADDITIONALLY...
SHOULD ANY ISOLD SHOWER ACTIVITY DEVELOP DURING PEAK HEATING...
STRONGER FLOW ALOFT COULD BE TRANSPORTED TO THE GROUND. -VINCENT
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 304 AM FRIDAY...
VERY DRY AND COLD SUNDAY...FOLLOWED BY GRADUAL WARMING INTO
MID-WEEK.
THE HEART OF THE STRONG (~1040 MB) COLD SURFACE HIGH PRESSURE IS
FORECAST TO MOVE FROM THE MISSISSIPPI VALLEY EAST TO OUR OUR REGION
BY EARLY MONDAY. A BRISK COLD SUNDAY IS FORECAST AS THE PRESSURE
GRADIENT IS FORECAST TO FINALLY WEAKEN LATE IN THE DAY AS THE HIGH
PRESSURE APPROACHES. LITTLE CHANGE WAS NOTED IN THE FORECAST LOW
LEVEL THICKNESSES AND THE CAA PATTERN FROM PREVIOUS FORECASTS.
THEREFORE... HIGHS IN THE UPPER 30S IN THE NW PIEDMONT RANGING TO
42-43 IN THE SANDHILLS IS EXPECTED.
THE MAIN WEATHER HAZARD WILL BE THE WIND CHILL READINGS SUNDAY
MORNING. THEY ARE FORECAST TO RANGE BETWEEN 10 AND 15 EXCEPT 5 TO 10
DEGREES BETWEEN SUNRISE AND NOON IN THE WINSTON-SALEM AND
GREENSBORO AREAS. AGAIN... THE MOST BLUSTERY CONDITIONS ARE EXPECTED
DURING SUNDAY MORNING WITH WNW WINDS AT 10-15 MPH SUSTAINED... WITH
GUSTS TO 25 MPH. WINDS DURING THE AFTERNOON WILL GRADUALLY DIMINISH.
THIS WILL CONTINUE TO BE HIGHLIGHTED IN THE HAZARDOUS WEATHER
OUTLOOK.
AS THE HIGH SETTLES OVERHEAD SUNDAY NIGHT... IT WILL BE CLEAR WITH A
HARD FREEZE. LOWS SHOULD BE IN THE 20-23 RANGE WITH PLENTY OF
OPPORTUNITY FOR THE RURAL AREAS OF THE PIEDMONT AND SANDHILLS TO DIP
INTO THE UPPER TEENS WITH THE CALM DRY CONDITIONS EXPECTED.
MONDAY AND TUESDAY...
ANOTHER BIG CHANGE IS FORECAST FROM COLD AND DRY MONDAY TO MILDER
CONDITIONS TUESDAY. THIS OCCURS AS THE MODELS SHOW THE COLD UPPER
TROUGH LIFTING OUT RAPIDLY MONDAY... FOLLOWED CLOSELY BY THE COLD
SURFACE HIGHS EXIT OFF THE COAST BY MONDAY NIGHT. IN ADDITION...
MODELS AND ENSEMBLES CONTINUE TO WAVER ON THE STRENGTH AND TRACK OF
A DAMPENING MID-UPPER LEVEL DISTURBANCE THAT IS FORECAST TO TRACK
RAPIDLY EAST ACROSS THE NORTHERN GULF COAST STATES INTO THE TN
VALLEY LATE MONDAY. THE FAVORED EC ACTUALLY DAMPENS THIS WAVE IN THE
INCREASINGLY ZONAL FLOW ALOFT BY THE TIME IT REACHES THE
APPALACHIANS EARLY TUESDAY IN SO MUCH THAT IT DEPICTS ZERO QPF OVER
OUR REGION TUESDAY. THIS SOLUTION HAS SUPPORT FROM THE GFS AND
ENSEMBLE FORECASTS WHICH ALL DEPICT VERY LITTLE IN THE WAY OF QPF
FOR OUR AREA TUESDAY. IT MAKES SENSE IF THE MID-UPPER DISTURBANCE
WEAKENS AS MUCH AS FORECAST. IN ADDITION... THE LOW LEVEL SUB-CLOUD
LAYER IS FORECAST TO BE DRY TUESDAY... DUE TO THE LINGERING AFFECTS
OF THE COLD DRY POLAR HIGH THAT WILL BE JUST OUT TO SEA AT THAT
TIME. WE WILL LEAVE CURRENT POP IN AS CURRENTLY ADVERTISED WITH A
SLIM CHANCE OF LIGHT RAIN TUESDAY. THE P-TYPE WOULD LIKELY BE RAIN
(WITH HIGH CONFIDENCE) IF WE DO GET ANY MEASURABLE PRECIP. THIS
GIVEN THE FORECAST WARMING ALOFT WITH MID LEVEL THICKNESSES IN THE
1550+ RANGE AND RISING BETWEEN 12Z-18Z... AND THE LOW LEVEL
THICKNESSES IN THE 1310M RANGE AND RISING. SENSIBLE WEATHER...
MOSTLY SUNNY & CHILLY MONDAY. HIGHS 47-52. INCREASING CLOUDS LATE
MONDAY AND MONDAY NIGHT WITH LOWS IN THE 30S. MOSTLY CLOUDY TUESDAY
WITH A SLIM CHANCE OF LIGHT RAIN. HIGHS IN THE 40S AND 50S NE TO S.
FOR TUESDAY NIGHT THROUGH THURSDAY...
MILD. VARIABLY CLOUDY. A NEW STORM WITH A VERY WARM LOOK FOR OUR
REGION EXPECTED LATE WEEK. MAIN STORM TRACK IS FAVORED EITHER ALONG
THE APPALACHIANS OR JUST TO THE WEST. WE WILL KEEP POP EITHER LOW OR
OUT OF THE FORECAST SINCE THIS WILL BE DAYS 6-8 OUT IN WHICH THE
NEXT MAIN STORM IS EXPECTED TO APPROACH NC.
SENSIBLE WEATHER... LOWS WEDNESDAY AND THURSDAY IN THE 40S. HIGHS
WEDNESDAY AND THURSDAY IN THE UPPER 50S TO MID 60S.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AS OF 1000 AM FRIDAY...
THROUGH 12Z SATURDAY:
VFR CONDITIONS WILL RULE THROUGH EARLY/MID AFTERNOON...WITH
DETERIORATING CONDITIONS IN THE COASTAL PLAIN (FAY/RWI) LATER THIS
AFTERNOON INTO TONIGHT. A LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP
ALONG THE CAROLINA COAST AS AN UPPER LEVEL DISTURBANCE PROGRESSES
EAST ACROSS THE AREA TONIGHT. MVFR/IFR CONDITIONS ASSOC/W RAIN ARE
EXPECTED TO DEVELOP NORTH INTO THE KFAY TERMINAL BY 19-22Z FOLLOWED
BY THE KRWI TERMINAL BY 22-01Z. UNCERTAINTY PERSISTS W/REGARD TO
WHETHER OR NOT SUB-VFR CONDITIONS WILL BE PRESENT FURTHER WEST AT
KRDU IN THE 00-06Z TIMEFRAME. THE BEST CHANCE FOR A PERIOD OF IFR
(AND POSSIBLY LIFR) CONDITIONS WILL BE AT KFAY/KRWI BETWEEN 22-06Z.
FURTHER WEST AT KINT/KGSO...VFR CONDITIONS ARE LIKELY TO PREVAIL
THROUGH THE TAF PERIOD.
LOOKING AHEAD:
ANY LINGERING SUB-VFR CONDITIONS AT FAY/RWI WILL END FROM WEST-EAST
BETWEEN 12-18Z SATURDAY AS THE LOW PRESSURE SYSTEM TRACKS NORTHEAST
AWAY FROM THE CAROLINAS...WITH VFR CONDITIONS THEREAFTER. IN THE
WAKE OF THE LOW...A STRONG ARCTIC COLD FRONT WILL SWEEP THROUGH THE
AREA FROM WEST-EAST BETWEEN 18-21Z SAT AFTERNOON. STRONG NORTHWEST
WINDS WILL BE PRESENT IN THE WAKE OF THE FRONT SAT AFTERNOON INTO
SAT NIGHT...BECOMING SUSTAINED AT 20-25 KT WITH GUSTS UP TO 35 KT.
THE STRONGEST WINDS ARE EXPECTED TO OCCUR BETWEEN 21Z SAT AND 03Z
SUNDAY WHEN THE MOST INTENSE PRESSURE RISES OCCUR. WINDS WILL WEAKEN
TO 10-15 KT SUSTAINED WITH GUSTS UP TO 20-25 KT DURING THE DAY
SUNDAY. VFR CONDITIONS WITH CLEAR SKIES ARE EXPECTED IN THE WAKE OF
THE FRONT THROUGH EARLY NEXT WEEK. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF/VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...DJF/VINCENT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
540 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
237 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUDS/TEMPERATURES/PRECIPITATION
TODAY...THEN WIND CHILLS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S INTO THE NORTHWEST
TERRITORIES OF CANADA...AND TROUGHING FROM THE DAKOTAS INTO QUEBEC.
WITHIN THIS TROUGH...A SHORTWAVE WAS PRESENT FROM NORTH DAKOTA INTO
NORTHERN MINNESOTA. A REMNANT STREAM OF PACIFIC MOISTURE AND DPVA
AHEAD OF THE SHORTWAVE HELPING TO PRODUCE A BAND OF MID-CLOUDS FROM
NORTHEAST SOUTH DAKOTA TO LAKE SUPERIOR. BELOW THIS...AN AREA OF
STRATUS RESULTING FROM MOISTURE TRAPPED IN A COLD FRONTAL INVERSION
WAS PRESENT FROM NORTHWEST IOWA INTO NORTHERN WISCONSIN. SOME LIGHT
SNOW WAS ALSO FALLING OUT OF THIS STRATUS OVER THE NORTH HALF OF
WISCONSIN...DUE TO THE PRESENCE OF LOW LEVEL FRONTOGENESIS PER RUC
ANALYSIS. THE THERMAL CONTRAST OF THE FRONTOGENESIS COULD BE SEEN
FROM A 00Z 850MB SOUNDING PLOT...NOTED BY A -6C TEMP AT MPX AND -17C
AT INL. AT THE SURFACE...A COLD FRONTAL BOUNDARY STRETCHED FROM
NORTHERN LAKE MICHIGAN SOUTHWEST TO DES MOINES...WHILE A 1041MB
ARCTIC HIGH PRESSURE AREA WAS OVER CENTRAL SASKATCHEWAN.
TODAY AND TONIGHT...SHORTWAVE OVER NORTH DAKOTA AND NORTHERN
MINNESOTA IS PROGGED TO MOVE THROUGH THE FORECAST AREA BETWEEN
15-21Z TODAY...ALLOWING THE ARCTIC HIGH PRESSURE AREA OVER
SASKATCHEWAN TO DROP SOUTH IN ITS WAKE. BY 12Z SATURDAY...THE HIGH
SHOULD BE SITUATED IN THE DAKOTAS. WITH THE HIGH WELL OFF TO THE
WEST...ANTICIPATING BLUSTERY CONDITIONS ACROSS MUCH OF THE FORECAST
AREA THROUGH TONIGHT. WIND DIRECTION IS A LITTLE INTERESTING. DUE TO
THE TRACK OF THE DEPARTING COLD FRONT...THE SURFACE-850MB WINDS ARE
MORE NORTH TO NORTHEAST TODAY...THEN SWITCHES TO THE NORTHWEST
TONIGHT. THIS WIND DIRECTION PATTERN MEANS THAT LOW LEVEL MOISTURE/
CLOUDS MAY GET STUCK OVER THE FORECAST AREA MORE TODAY...AIDED BY
MOISTENING OFF LAKE SUPERIOR. ONCE THE WINDS GO NORTHWEST...THE DRY
ARCTIC AIR CAN FLOW IN AND CLEAR OUT THE STRATUS. ONE CAVEAT IS THAT
RIGHT NOW THE AIR OVER NORTHERN ONTARIO IS DRIER THAN THE MODELS
SUGGEST. WILL HAVE TO WATCH TO SEE THROUGH THE DAY TODAY ON HOW MUCH
OF THIS DRIER AIR OVER NORTHERN ONTARIO ADVECTS SOUTH. NEXT CONCERN
IS THE PRECIPITATION. THE 10.00Z NAM AND HRRR RUNS HAVE SHOWN SOME
VERY LIGHT SNOW/FLURRIES...MOSTLY ALONG AND EAST OF THE MISSISSIPPI
RIVER THIS MORNING. LOW LEVEL FRONTOGENETICAL FORCING APPEARS TO BE
THE MAIN PRODUCTION FEATURE...WITH THE SNOW MORE LIKELY TO OCCUR DUE
TO THE STRATUS EVENTUALLY INTERSECTING THE DENDRITIC GROWTH ZONE AS
THE COLDER AIR MOVES IN. A FEW TENTHS SEEM POSSIBLE. HAVE LEFT SOME
FLURRIES IN FOR THE AFTERNOON TOO...BUT THINK THE BULK OF ANY
ACCUMULATING TYPE SNOW WOULD BE OFF TO THE EAST WHERE THE LOW LEVEL
FRONTOGENESIS IS EXPECTED. FINAL CONCERN IS TEMPERATURES. 850MB
TEMPS REALLY DROP TODAY...FROM -8C SOUTHEAST TO -16C NORTHWEST
ACROSS THE FORECAST AREA AT 12Z...TO BASICALLY AROUND -20C AT 00Z.
WITH STRATUS IN PLACE AND FALLING 850MB TEMPS...LOOK FOR SURFACE
TEMPERATURES TO SLOWLY FALL THROUGH THE DAY...DROPPING WIND CHILLS.
TONIGHT...THE TEMPERATURE FALL WILL MAINLY BE A RESULT OF ADVECTION
DUE TO BLUSTERY CONDITIONS KEEPING THE BOUNDARY LAYER MIXED.
STILL...LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO SUGGESTED BY
GUIDANCE AND THE PREVIOUS FORECAST SEEM REASONABLE. MAY NEED WIND
CHILL ADVISORIES FOR PORTIONS OF THE AREA VERY LATE...MOST LIKELY
TAYLOR AND CLARK ZONES. GIVEN SUCH A SMALL AREA AND MARGINAL WIND
CHILLS AT THAT...HELD OFF ON ISSUING AN ADVISORY AT THIS TIME.
SATURDAY THROUGH SUNDAY NIGHT...FAIRLY QUIET PERIOD EXPECTED AS
500MB HEIGHTS GRADUALLY BUILD. ARCTIC HIGH PRESSURE AREA NEVER
BUILDS OVER THE AREA...TRACKING MORE SOUTH TO THE LOWER MISSISSIPPI
RIVER VALLEY BY MID-DAY SUNDAY. THIS TRACK SHOULD KEEP CONDITIONS
FROM DECOUPLING SATURDAY NIGHT...PREVENTING ANY DRAMATIC TEMPERATURE
FALL FROM RADIATIONAL COOLING. ONLY REAL CONCERN IS SUNDAY NIGHT.
DURING THIS PERIOD...MODELS HAVE UPPER TROUGHING CROSSING THE
WESTERN U.S. TOWARDS THE PLAINS WITH RIDGING BUILDING UP TOWARDS THE
FORECAST AREA. 10.00Z NAM HINTS THAT A FEW WEAK SHORTWAVES MAY COME
OUT OF THE TROUGH AND APPROACH THE AREA BY 12Z MONDAY. WITH THESE
SHORTWAVES...THE NAM BRINGS SOME PRECIPITATION INTO NORTHEAST IOWA
AFTER MIDNIGHT SUNDAY NIGHT. BY FAR THE NAM IS THE FASTEST OF ANY
GUIDANCE AND THEREFORE FOR NOW HAS BEEN DISCOUNTED. HAVE DRIED OUT
ALMOST ALL OF THE FORECAST AREA AS A RESULT...THOUGH LEFT A 20
PERCENT CHANCE FOR CHARLES CITY TO OELWEIN IA JUST IN CASE THE
FASTER SCENARIO WOULD PLAY OUT. AN INCREASE IN MID TO UPPER LEVEL
CLOUD COVER IS LIKELY SUNDAY NIGHT...HOWEVER. A GRADUAL WARMING
TREND IS ANTICIPATED THROUGH THE WEEKEND AS THE ARCTIC HIGH SLOWLY
MODIFIES...HELPED TOO BY THE GENERAL LACK OF SNOW COVER FROM THE
DAKOTAS INTO THE UPPER MISSISSIPPI RIVER VALLEY. 850MB TEMPS CLIMB
TO -12C BY 00Z SUNDAY AND -6C BY 00Z MONDAY. WITH THE WARMING 850MB
TEMPS...HIGHS SHOULD CLIMB INTO THE 15 TO 20F RANGE ON SATURDAY AND
25 TO 30F RANGE ON SUNDAY.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
237 AM CST FRI FEB 10 2012
OVERALL PATTERN LOOKS FAIRLY BENIGN THROUGHOUT MUCH OF THE LONG TERM
PERIOD SUGGESTED BY THE 10.00Z ECMWF/CANADIAN/GFS/UKMET AND GFS
ENSEMBLES. A SPLIT FLOW SCENARIO IS FORECAST BY ALL OF THESE
MODELS...WITH THE NORTHERN STREAM FEATURING ZONAL TO WEAK TROUGHING
ACROSS SOUTHERN CANADA...AND A SOUTHERN STREAM FEATURING TROUGHING
IN THE SOUTHWEST U.S. TO ZONAL TO SLIGHT RIDGING OVER THE
SOUTHEASTERN U.S.. THIS MEANS MOST OF THE PRECIPITATION ACTION ENDS
UP STAYING TO THE NORTH AND SOUTH OF THE FORECAST AREA WITH NO COLD
SHOTS IN THE OFFERING. THE ONLY EXCEPTION TO THE PRECIPITATION IS
MONDAY INTO MONDAY EVENING...DUE TO THE COMBINATION OF WEAK LOW
LEVEL MOISTURE TRANSPORT AND WEAK SHORTWAVES PROGGED TO MOVE THROUGH
THE AREA. THESE SHORTWAVES ORIGINATING OUT OF THE TROUGHING MOVING
INTO THE PLAINS SUNDAY NIGHT. THERE REMAINS STRONG CONTINUITY FOR
PRECIPITATION SOUTH OF I-90...SO MAINTAINED 50-60 PERCENT CHANCES
THERE FOR MONDAY. PRECIPITATION CHANCES TAPER OFF HEADING NORTH AS
CONFIDENCE IN MOISTURE AVAILABILITY IS LOWER. DOES NOT LOOK LIKE
ANYTHING BIG IN TERMS OF SNOW ACCUMULATION GIVEN THE WEAK
FORCING...PERHAPS AROUND AN INCH. A LITTLE FARTHER OUT...THE 10.00Z
ECMWF/CANADIAN BOTH HINT AT SOME SHORTWAVE TROUGHS CROSSING THE AREA
WEDNESDAY NIGHT INTO THURSDAY...ORIGNIATING FROM SOUTHERN EXTENSIONS
OFF THE NORTHERN STREAM. WITH LACK OF MOISTURE...KEPT THE CONSENSUS
15 TO 20 PERCENT CHANCES. WOULD NOT BE SURPRISED IF IT ENDS UP DRY.
TEMPERATURES THROUGHOUT THE LONG TERM PERIOD SHOULD END UP AT OR
ABOVE NORMAL DUE TO ALL THE COLD AIR BEING LOCKED BACK UP OVER
NORTHERN CANADA. IN FACT...IT APPEARS THE GENERAL ABOVE NORMAL
CONDITIONS WILL PERSIST AT LEAST FOR THE NEXT ONE TO TWO WEEKS...IF
NOT LONGER...PER THE CFS VERSION 2 FORECASTS.
&&
.AVIATION...TODAY AND TONIGHT
531 AM CST FRI FEB 10 2012
THE 10.00Z AND 10.06Z MODELS CONTINUE TO SHOW THAT A MVRF AROUND
2K FEET WILL LINGER ACROSS THE AREA THROUGH EARLY THIS
AFTERNOON...AND THEN SLOWLY RISE INTO THE 3-5K FOOT RANGE BETWEEN
10.20Z AND 11.00Z. SKIES SHOULD RAPIDLY CLEAR BETWEEN 11.00Z AND
11.04Z.
NORTH WINDS WILL BE SUSTAINED IN THE 15 TO 25 KNOT RANGE WITH
OCCASIONAL WIND GUSTS UP TO 30 KNOTS TODAY. THE WINDS WILL SHIFT
TO NORTHWEST AND DECREASE TO 10 TO 20 KNOTS THIS EVENING. THESE
WINDS WILL THEN CONTINUE THROUGH THE OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 AM CST FRI FEB 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
400 PM EST Fri Feb 10 2012
...Much colder weather arriving this weekend...
.SYNOPSIS...
20Z water vapor and H4 RUC analysis shows and amplified upper level
pattern consisting of ridging in place from California through much
of the inter-mountain region and downstream troughing covering the
remainder of the CONUS. There area two main features of note
embedded within the main longwave trough. The first is a strong
shortwave diving southward over the upper MS valley that represents
the leading edge of a significant arctic intrusion. The second is
shortwave energy exiting the southern Plains toward the northern
Gulf Coast. This second piece of energy will bring showers to the
area overnight, however is expected to be a low impact event.
Regional radars are showing expanding echoes across the area,
especially in a band from PC beach to Tallahassee, and Valdosta.
Analysis of the 12Z KTLH sounding showed a significant dry layer
above the surface which had been generally preventing these showers
from reaching the surface, but this layer has been moistening and
will now begin to see more and more raindrops reach the surface.
At the surface,
Analysis shows weakening high pressure over the Southeast U.S.
Currently we are under this high "sandwiched" between a weak
inverted surface trough along the Florida East Coast, and an
organizing cold front along the middle/lower MS Valley.
&&
.SHORT TERM (Tonight through Sunday Night)...
Tonight,
A mid/upper level shortwave trough will pivot rapidly eastward along
the northern Gulf coast. Decent swath of synoptic support/QG forcing
ahead of this energy will overspread the area this evening. This
area of forcing is already supporting a large area of showers across
southern LA/MS. Global and hi-res model consensus agrees that this
area of showers will expand rapidly into our region this evening.
The QG forcing will align with upper level jet energy to support the
highest shower concentration over the southern half of the
area...and especially coastal areas eastward through the SE Big
Bend. These areas are highlighted with high end 70% PoPs, and an
argument could easily be made for higher categorical PoPs. PoP
gradient will decrease to the north down to 40-50% up toward KDHN
and KABY. Still do expect some of the showers to reach this far
north, however some guidance members insist that the main area of
showers will be more broken in nature north of the FL border. Even
across the far south...this will be a high PoP...low QPF event, with
highest rainfall amounts likely remaining under 1/4 inch. This will
be a quick hitting event as the last of the organized showers are
expected to be exiting the Suwannee River Valley/I-75 corridor by
around 09Z. Surface based CAPE is essential nil, and even elevated
instability is lacking. Showalter indices are all positive and will
not include thunder mention. Low temperatures in the 40s.
Saturday,
Cold front will quickly pass east of the forecast area Saturday
morning with a much cooler and drier airmass arriving on breezy NW
winds. 850mb temps will fall below 0C over most areas by the end of
the day. Despite the strength of the cold air...excellent diurnal
mixing in the post-frontal environment will keep things seasonable
for afternoon highs. Looking for highs to range from the lower 50s
north and west of a Dothan to Albany line, and range upward to the
lower 60s over the SE Big Bend zones. As mentioned above it will be
quite breezy for those with outdoor plans. NW winds sustained
between 15 to 20 mph with gusts near 25 mph common.
Saturday Night,
The cold air will arrive quickly with the setting of the sun. At
this time expecting temperatures by sunrise on Sunday to be
generally in the upper 20s...with middle 20s possible across the far
north. Current statistical guidance shows lower/middle 20s for
many locations, however, MOS guidance almost always is too low in
these events with respect to the initial advection freeze...and have
taken this bias into account. This will only prevent a hard freeze.
Still anticipate a widespread freeze even right down to the coast.
Combine these temps with a steady northerly breeze and wind chill
reading will reach the upper teens to lower 20s. Will continue to
monitor the situation in case a wind chill advisory becomes
necessary for early Sunday morning.
Sunday/Sunday night,
High pressure will settle southeast from the TN valley toward the
forecast area. The airmass in place and less efficient mixing
will result in a cool day. High temps will struggle into the lower
50s by the late afternoon. The close proximity of the high center
will cause any light afternoon winds will go nearly calm quickly
during the evening. These calm conditions combined with very dry low
levels suggest temps will fall quickly after sunset. Expect to see
normally colder areas fall below freezing potentially by late
evening, and set up a long duration freeze. This appears to be the
night in which hard freeze conditions will be more likely. Low temps
for normally colder areas may drop into the lower 20s...with most
locations away from the immediate coast falling into the middle 20s.
As is usual with radiational cooling...the immediate coast and more
urbanized inland centers (such as downtown Tallahassee) should end
up a few degrees warmer, but still below freezing.
&&
.LONG TERM (Monday through next Friday)...
We`ll see another cold day to start the extended period with
possibly another widespread hard freeze Monday morning mainly east
of the Apalachicola/Chattahoochee Rivers. Surface high pressure will
be centered over the southeast CONUS with nearly zonal flow aloft on
Monday. The high will rapidly move east making way for the next low
pressure system that will bring a weak cold front with rain chances
to the region on Tuesday. This front will stall over or just south
of our FA late Tuesday/early Wednesday and then lift north as a warm
front Wednesday/Wednesday night as a stronger low pressure system
begins to develop over the southern plains. Showers/thunderstorms
will begin to overspread the region during the Thursday/Thursday
night time frame with the front forecast to push into the CWA on
Friday. After below normal temps for Monday, the rest of the
extended period will have above seasonal temps.
&&
.MARINE
A weak area of low pressure will pass south of the forecast waters
this evening. In the wake of this low, winds will increase from the
Northwest later tonight and are forecast to reach advisory levels
Saturday morning. These advisory level conditions will continue
through Sunday morning. A period of gale force gusts is possible
Saturday night and this potential will need to be monitored closely.
Winds and seas will decrease below headline criteria later Sunday
into the early portion of next week.
&&
.Aviation (through 18Z Sat)...Although Vfr conditions should prevail
through the bulk of this Taf period, gradually lowering Vfr level
cigs will predominate the fcst for the remainder of this afternoon
and throughout much of the evening hours. Widespread light rain is
also expected to develop from SW to NE across the terminals, with
possible periods of moderate rain and Mvfr level Vis this evening at
TLH, ECP, and VLD. Although some VFR level clouds could linger
behind the cold front for a while, Saturday should be dominated by
clearing skies, much cooler temps, and very gusty NW winds.
&&
.FIRE WEATHER...
Much cooler and drier air will be building in from the northwest on
Saturday on gusty Northwest winds. This very dry air combined with
sustained 15 mph or greater winds and Dispersions greater than 75
will result in a Red Flag Warning for all of the Florida Big Bend
and Panhandle on Saturday. However, even though relative humidity
values will be extremely low over the same area on Sunday, will hold
off on a Fire Weather Watch until future ERC values can be
determined. Over Southeast Alabama and Southwest and South Central
Georgia, will issue a Fire Weather Watch for Sunday for expected
long durations of relative humidity below 25 percent.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 42 60 27 52 24 / 70 0 0 0 0
Panama City 47 59 31 52 31 / 70 0 0 0 0
Dothan 42 54 27 51 26 / 50 0 0 0 0
Albany 41 56 26 52 25 / 40 0 0 0 0
Valdosta 44 59 27 52 25 / 60 0 0 0 0
Cross City 45 65 28 53 23 / 70 0 0 0 0
Apalachicola 45 60 30 52 29 / 70 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Fire Weather Watch from Sunday morning through Sunday afternoon
for Coffee-Dale-Geneva-Henry-Houston.
GA...Fire Weather Watch from Sunday morning through Sunday 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.
FL...Red Flag Warning from 2 PM EST /1 PM CST/ to 7 PM EST /6 PM CST/
Saturday 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 from 7 AM Saturday to 10 AM EST Sunday 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...Barry
Aviation/Fire Wx...Gould
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
218 PM CST FRI FEB 10 2012
.DISCUSSION...
120 PM CST
THE ARCTIC FRONT IS SWINGING SOUTH INTO NORTHEAST IL EARLY THIS
AFTERNOON. IMMEDIATELY ALONG THIS IS AN ENHANCED AREA OF SNOWFALL
THAT HAS A HISTORY OF REDUCING VISIBILITY TO ONE QUARTER MILE OR
LESS. THIS IS CORRELATED TO STEEP LOW-LEVEL LAPSE RATES AND STRONG
CONVERGENCE. SHORT TERM GUIDANCE INDICATES THIS WILL CONTINUE TO
PROPAGATE SOUTH THROUGH THE CHICAGO METRO AREA. SNOWFALL BEHIND
THIS WITHIN THE MID-LEVEL FORCING AND CONTINUED STEEP LOW-LEVEL
LAPSE RATES HAS ALSO BEEN MODERATE IN INTENSITY. THIS HAS SHOWN
SIGNS OF BEING LAKE ENHANCED AT TIMES NEAR THE LAKE SHORE...WITH
THUNDER REPORTED EARLIER IN FOND DU LAC. THIS AREA SHOULD ALSO
HOLD TOGETHER CONTINUING SNOWFALL ACROSS CHICAGO AFTER THE
IMMEDIATE FRONTAL PASSAGE...AND LIKELY INTO THE LATE AFTERNOON
RUSH HOUR. MORE TRULY LAKE EFFECT SNOW IS EXPECTED TO ALSO DEVELOP
INTO NORTHEAST IL LATE THIS AFTERNOON AND EARLY THIS EVENING
BEFORE ESTABLISHING ITSELF INTO FAR SOUTHEAST COOK COUNTY AND
NORTHWEST INDIANA.
MTF
//PREV DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CIGS DOWN BLO 1000FT AGL...WILL HOVER ARND THIS HEIGHT THRU
REMAINDER OF THIS AFTN EARLY EVENING.
* NORTHWEST WINDS VEER NORTH. A PERIOD OF TIME WINDS MAY BLEED
NORTHEAST FOR A TEMPO BETWEEN 20-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 20Z...
LATEST RADAR REFLECTIVITY CONCERNING PLACEMENT OF MOST INTENSE
SNOW WAS SLIDING SOUTH ACROSS NORTHERN COOK COUNTY...WHICH WAS
IMPACTING ORD AND EXPECTED TO IMPACT MDW WITHIN THE NEXT 30-45
MINUTES. THIS WAS BRINGING VSBYS DOWN FOR A TEMPO TO 1/4SM AND
+SN. ON BACK SIDE OF THIS SLUG OF POTENT SNOW VSBYS SHUD COME BACK
UP TO ARND 1SM WITH -SN. CIGS HAVE ALSO REDUCED TO ARND
VV007...ALTHOUGH ANTICIPATE THIS TO BE SHORT LIVED AND CIGS SHUD
HOVER ARND 800-1000FT AGL. LAKE EFFECT SNOW WAS ALSO FORMING
ACROSS EAST CENTRAL WISCONSIN AND EXPECTED TO CLIP ORD/MDW LATER
THIS AFTN. WINDS HAVE ALSO PUSHED NORTHEAST AT 010-020...AGAIN
EXPECTED TO BE SHORT-LIVED AND COME BACK TO A 350-360 DIRECTION.
SPEEDS WILL COTNINUE TO INCREAS AS WELL TO ARND SUSTAINED 15-18KT
WITH OCCASIONAL GUSTS TO 25-28KT. VISIBLE IMAGERY WAS ALSO
INDICATING SOME CONVECTIVE ELEMENTS TO THE CLOUDS...WHICH
INDICATES SOME STRONG LIFT AND POSSIBLE THUNDER. ALTHOUGH THIS IS
A REMOTE POSSIBILITY...IT SHOULD BE NOTED. AS THIS COULD ENHANCE
SNOW OVER A FEW AIRFIELDS.
PREVIOUS DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
156 PM CST
THE MAIN CONCERNS CONTINUE TO FOCUS ON THE STRONG WINDS ACROSS LAKE
MICHIGAN TONIGHT INTO SATURDAY. THE STRONG SURFACE COLD FRONT IS
MOVING ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN EARLY THIS
AFTERNOON. I EXPECT NORTHERLY GALE FORCE WINDS AROUND 35 KNOTS IN
THE WAKE OF THIS FRONT. AS VERY COLD AIR CONTINUES TO SPILL OVER THE
LAKE THIS EVENING...A FAVORABLE THERMODYNAMIC SETUP WILL OCCUR FOR A
BANDS OF INTENSE LAKE EFFECT SNOW TO DEVELOP. THERE IS ALSO A GOOD
POSSIBILITY THAT AS SOME AREAS ACROSS THE SOUTHERN END OF THE LAKE
MAY SEE GALES INCREASE TO 40 KT FOR A PERIOD TONIGHT AS THESE
CONVERGENT BANDS OF SNOW DEVELOP. THESE STRONG WINDS WILL LIKELY
ALSO AFFECT THE INDIANA NEAR SHORE WATERS.
WINDS WILL ABATE SOME ON SATURDAY. HOWEVER...THE PRESSURE GRADIENT
WILL REMAIN FAIRLY TIGHT ACROSS THE LAKE AS HIGH PRESSURE DROPS OUT
OF SOUTHERN CANADA AND BUILDS ACROSS THE LOWER AND MIDDLE MISSOURI
RIVER VALLEY. THEREFORE...EXPECT NORTHWEST WINDS TO 30 KT TO
CONTINUE ON SATURDAY AND SATURDAY NIGHT. THIS SURFACE HIGH WILL
BUILD EASTWARD ACROSS THE OHIO VALLEY ON SUNDAY AND SUNDAY NIGHT.
ONCE THIS OCCURS THE WINDS WILL BECOME WEST SOUTHWESTERLY BY MONDAY.
WIND SPEEDS WILL DIMINISH INTO MONDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002 UNTIL 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 10 AM SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...10 AM SATURDAY TO
2 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 PM CST FRI FEB 10 2012
.DISCUSSION...
120 PM CST
THE ARCTIC FRONT IS SWINGING SOUTH INTO NORTHEAST IL EARLY THIS
AFTERNOON. IMMEDIATELY ALONG THIS IS AN ENHANCED AREA OF SNOWFALL
THAT HAS A HISTORY OF REDUCING VISIBILITY TO ONE QUARTER MILE OR
LESS. THIS IS CORRELATED TO STEEP LOW-LEVEL LAPSE RATES AND STRONG
CONVERGENCE. SHORT TERM GUIDANCE INDICATES THIS WILL CONTINUE TO
PROPAGATE SOUTH THROUGH THE CHICAGO METRO AREA. SNOWFALL BEHIND
THIS WITHIN THE MID-LEVEL FORCING AND CONTINUED STEEP LOW-LEVEL
LAPSE RATES HAS ALSO BEEN MODERATE IN INTENSITY. THIS HAS SHOWN
SIGNS OF BEING LAKE ENHANCED AT TIMES NEAR THE LAKE SHORE...WITH
THUNDER REPORTED EARLIER IN FOND DU LAC. THIS AREA SHOULD ALSO
HOLD TOGETHER CONTINUING SNOWFALL ACROSS CHICAGO AFTER THE
IMMEDIATE FRONTAL PASSAGE...AND LIKELY INTO THE LATE AFTERNOON
RUSH HOUR. MORE TRULY LAKE EFFECT SNOW IS EXPECTED TO ALSO DEVELOP
INTO NORTHEAST IL LATE THIS AFTERNOON AND EARLY THIS EVENING
BEFORE ESTABLISHING ITSELF INTO FAR SOUTHEAST COOK COUNTY AND
NORTHWEST INDIANA.
MTF
//PREV DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIGS DOWN TO ARND 1500FT AGL...WILL CONTINUE TO LOWER AS ADDTL SNOW
DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
156 PM CST
THE MAIN CONCERNS CONTINUE TO FOCUS ON THE STRONG WINDS ACROSS LAKE
MICHIGAN TONIGHT INTO SATURDAY. THE STRONG SURFACE COLD FRONT IS
MOVING ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN EARLY THIS
AFTERNOON. I EXPECT NORTHERLY GALE FORCE WINDS AROUND 35 KNOTS IN
THE WAKE OF THIS FRONT. AS VERY COLD AIR CONTINUES TO SPILL OVER THE
LAKE THIS EVENING...A FAVORABLE THERMODYNAMIC SETUP WILL OCCUR FOR A
BANDS OF INTENSE LAKE EFFECT SNOW TO DEVELOP. THERE IS ALSO A GOOD
POSSIBILITY THAT AS SOME AREAS ACROSS THE SOUTHERN END OF THE LAKE
MAY SEE GALES INCREASE TO 40 KT FOR A PERIOD TONIGHT AS THESE
CONVERGENT BANDS OF SNOW DEVELOP. THESE STRONG WINDS WILL LIKELY
ALSO AFFECT THE INDIANA NEAR SHORE WATERS.
WINDS WILL ABATE SOME ON SATURDAY. HOWEVER...THE PRESSURE GRADIENT
WILL REMAIN FAIRLY TIGHT ACROSS THE LAKE AS HIGH PRESSURE DROPS OUT
OF SOUTHERN CANADA AND BUILDS ACROSS THE LOWER AND MIDDLE MISSOURI
RIVER VALLEY. THEREFORE...EXPECT NORTHWEST WINDS TO 30 KT TO
CONTINUE ON SATURDAY AND SATURDAY NIGHT. THIS SURFACE HIGH WILL
BUILD EASTWARD ACROSS THE OHIO VALLEY ON SUNDAY AND SUNDAY NIGHT.
ONCE THIS OCCURS THE WINDS WILL BECOME WEST SOUTHWESTERLY BY MONDAY.
WIND SPEEDS WILL DIMINISH INTO MONDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002 UNTIL 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
124 PM CST FRI FEB 10 2012
.DISCUSSION...
120 PM CST
THE ARCTIC FRONT IS SWINGING SOUTH INTO NORTHEAST IL EARLY THIS
AFTERNOON. IMMEDIATELY ALONG THIS IS AN ENHANCED AREA OF SNOWFALL
THAT HAS A HISTORY OF REDUCING VISIBILITY TO ONE QUARTER MILE OR
LESS. THIS IS CORRELATED TO STEEP LOW-LEVEL LAPSE RATES AND STRONG
CONVERGENCE. SHORT TERM GUIDANCE INDICATES THIS WILL CONTINUE TO
PROPAGATE SOUTH THROUGH THE CHICAGO METRO AREA. SNOWFALL BEHIND
THIS WITHIN THE MID-LEVEL FORCING AND CONTINUED STEEP LOW-LEVEL
LAPSE RATES HAS ALSO BEEN MODERATE IN INTENSITY. THIS HAS SHOWN
SIGNS OF BEING LAKE ENHANCED AT TIMES NEAR THE LAKE SHORE...WITH
THUNDER REPORTED EARLIER IN FOND DU LAC. THIS AREA SHOULD ALSO
HOLD TOGETHER CONTINUING SNOWFALL ACROSS CHICAGO AFTER THE
IMMEDIATE FRONTAL PASSAGE...AND LIKELY INTO THE LATE AFTERNOON
RUSH HOUR. MORE TRULY LAKE EFFECT SNOW IS EXPECTED TO ALSO DEVELOP
INTO NORTHEAST IL LATE THIS AFTERNOON AND EARLY THIS EVENING
BEFORE ESTABLISHING ITSELF INTO FAR SOUTHEAST COOK COUNTY AND
NORTHWEST INDIANA.
MTF
&&
.PREV DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIGS DOWN TO ARND 1500FT AGL...WILL CONTINUE TO LOWER AS ADDTL SNOW
DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002 UNTIL 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1202 PM CST FRI FEB 10 2012
.DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIGS DOWN TO ARND 1500FT AGL...WILL CONTINUE TO LOWER AS ADDTL SNOW
DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001...3 PM FRIDAY TO 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002...3 PM FRIDAY TO 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...3 PM FRIDAY TO NOON
SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1023 AM CST FRI FEB 10 2012
.DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CIGS DOWN TO ARND 1600FT AGL...WILL CONTINUE TO LOWER AS ADDTL
SNOW DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 12Z...
A LOW PRESSURE SYSTEM PASSES TO THE NORTH TODAY...BUT ITS COLD
FRONT WILL PASS THROUGH THE REGION LATE THIS MORNING THROUGH EARLY
THIS AFTERNOON. LIGHT SNOW SHOWERS WILL SPREAD ACROSS THE REGION
AND WINDS WILL TURN NORTHERLY BEHIND THE FRONT. EXPECTING MVFR
VSBY IN THE LIGHT SNOW SHOWERS. MODELS INDICATE THERE WILL BE
LAKE ENDUCED LIFT AFFECTING REACHING AS FAR INWARD AS ORD AND MDW.
THE ENHANCED LIFT LOOKS LIKE IT WILL BE BELOW THE IDEAL SNOW
GROWTH ZONE...WHICH WILL RESULT IN VERY FINE SNOW FLAKES. WHILE
NOT EXPECTING MORE THAN 1 TO 2 INCHES OF TOTAL SNOW ACCUMULATION
TODAY FOR MDW AND ORD...AN ABUNDANCE OF SMALL SNOW FLAKES COMBINED
WITH WIND GUSTS UP TO 30 KT WILL RESULT IN IFR TO LIFR VSBYS THIS
AFTERNOON.
WINDS WILL TURN MORE NORTHWESTERLY LATE THIS AFTERNOON...WHICH
WILL PUSH THE SNOW BAND INTO NORTHWEST INDIANA. GYY WILL BE
HARDEST HIT BY THE SNOW TODAY...WITH AT LEAST 5 TO 7 INCHES OF
SNOW POSSIBLE. MORE SNOW COULD ACCUMULATE DEPENDING ON HOW LONG
THE LAKE EFFECT SNOW BAND RESIDES OVER GYY. LUCKILY...EXPECTING
THE WORST OF THE SNOW TO OCCUR AFTER OPERATING HOURS.
CONDITIONS WILL RAPIDLY IMPROVE BEHIND THE SNOW...WITH VFR
EXPECTED BY SATURDAY MORNING AT ALL TERMINALS EXCEPT GYY. GUSTY
NORTHWEST WINDS WILL CONTINUE THROUGH TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001...3 PM FRIDAY TO 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002...3 PM FRIDAY TO 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...3 PM FRIDAY TO NOON
SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1007 AM CST FRI FEB 10 2012
.DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
&&
.PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* CIGS REDUCING FROM MVFR NEAR IFR CONDS THIS AFTN.
* WEST WINDS VEERING NORTH THIS AFTERNOON.
* OCCASIONAL WIND GUSTS UP TO 30 KT.
* PSBL PERIODS OF IFR VSBYS WITH THE BURSTS OF SNOW.
BEACHLER
//DISCUSSION...UPDATED 12Z...
A LOW PRESSURE SYSTEM PASSES TO THE NORTH TODAY...BUT ITS COLD
FRONT WILL PASS THROUGH THE REGION LATE THIS MORNING THROUGH EARLY
THIS AFTERNOON. LIGHT SNOW SHOWERS WILL SPREAD ACROSS THE REGION
AND WINDS WILL TURN NORTHERLY BEHIND THE FRONT. EXPECTING MVFR
VSBY IN THE LIGHT SNOW SHOWERS. MODELS INDICATE THERE WILL BE
LAKE ENDUCED LIFT AFFECTING REACHING AS FAR INWARD AS ORD AND MDW.
THE ENHANCED LIFT LOOKS LIKE IT WILL BE BELOW THE IDEAL SNOW
GROWTH ZONE...WHICH WILL RESULT IN VERY FINE SNOW FLAKES. WHILE
NOT EXPECTING MORE THAN 1 TO 2 INCHES OF TOTAL SNOW ACCUMULATION
TODAY FOR MDW AND ORD...AN ABUNDANCE OF SMALL SNOW FLAKES COMBINED
WITH WIND GUSTS UP TO 30 KT WILL RESULT IN IFR TO LIFR VSBYS THIS
AFTERNOON.
WINDS WILL TURN MORE NORTHWESTERLY LATE THIS AFTERNOON...WHICH
WILL PUSH THE SNOW BAND INTO NORTHWEST INDIANA. GYY WILL BE
HARDEST HIT BY THE SNOW TODAY...WITH AT LEAST 5 TO 7 INCHES OF
SNOW POSSIBLE. MORE SNOW COULD ACCUMULATE DEPENDING ON HOW LONG
THE LAKE EFFECT SNOW BAND RESIDES OVER GYY. LUCKILY...EXPECTING
THE WORST OF THE SNOW TO OCCUR AFTER OPERATING HOURS.
CONDITIONS WILL RAPIDLY IMPROVE BEHIND THE SNOW...WITH VFR
EXPECTED BY SATURDAY MORNING AT ALL TERMINALS EXCEPT GYY. GUSTY
NORTHWEST WINDS WILL CONTINUE THROUGH TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM-HIGH CONFIDENCE WITH TRENDS AND TIMING THIS
AFTERNOON...INCLUDING SNOW...VSBY...AND CIGS.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST TRENDS...MEDIUM
CONFIDENCE IN WIND SHIFT TIMING.
* MEDIUM-HIGH CONFIDENCE IN CIG FORECAST.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001...3 PM FRIDAY TO 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002...3 PM FRIDAY TO 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...1 PM
FRIDAY TO 9 AM SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...3 PM FRIDAY TO NOON
SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
224 PM EST FRI FEB 10 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
AN UPPER TROUGH MOVING EAST ACROSS THE CENTRAL AND SOUTHERN
MISSISSIPPI VALLEY WILL SPREAD LIGHT PRECIP INTO OUR REGION BY
AFTERNOON AS AN ARCTIC COLD FRONT OVER THE UPPER MIDWEST MOVES
ACROSS OUR REGION LATE TODAY AND EARLY TONIGHT. ON SATURDAY A COLD
FLOW OF ARCTIC AIR WILL BE ACROSS OUR REGION. SOME LAKE EFFECT
FLURRIES POSSIBLE MAINLY NORTH AND EAST. HIGH PRESSURE OVER THE
NORTHERN THIS WEEKEND WILL MOVE ACROSS OUR REGION LATE SUNDAY AND
EARLY MONDAY. THE COMBINATION OF WARM ADVECTION AND AN UPPER LEVEL
DISTURBANCE WILL BRING PRECIP ACROSS OUR REGION BY LATE MONDAY INTO
TUESDAY.
FARTHER INTO THE EXTENDED...SOME MODELS INDICATE ANOTHER WEAK
DISTURBANCE MAY AFFECT US BY THURSDAY.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE ADJUSTMENTS TO THE FORECAST BASED ON RUC WETBULB
TEMPERATURE PROGS. APPEARS 35F IS A GOOD LINE FOR WHERE SNOW
TRANSITIONS TO RAIN...SO BASED ON THIS HAVE ADJUSTED GRIDS TO
DEPICT LIKELY RAIN OR SNOW SOUTHWEST...LIKELY SNOW-SLIGHT CHANCE
TO CHANCE OF RAIN NORTHEAST OF THERE...AND THEN ALL SNOW ACROSS
THE NORTHEASTERN HALF OF THE FORECAST AREA...ROUGHLY FROM A LAF-
IND-BAK LINE NORTHEAST.
AMOUNTS REMAIN ROUGHLY THE SAME...FROM HALF INCH OR SO IN THE
SOUTHWEST...TO 1 TO AS HIGH AS 2 CENTRAL AND NORTHEAST...WITH
HIGHEST AMOUNTS NEAR MUNCIE.
DROPPED TEMPS SLIGHTLY ALSO BASED ON WETBULB TEMPS AND HOURLY
NUMERICAL GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT WILL BE MOVING THROUGH THIS EVENING AND MODELS HAVE
TRENDED A LITTLE SLOWER IN ENDING PRECIP. MOST OF THIS WILL OCCUR
BETWEEN 00Z AND 06Z AND SHOULD BE PRIMARILY ALL SNOW. WITH
TEMPERATURES DROPPING WELL BELOW FREEZING AND WINDS
INCREASING...THERE SHOULD BE SOME ISSUES WITH SLIPPERY ROADS
TONIGHT. WILL CONTINUE SPECIAL WEATHER STATEMENT ON THIS. TOTAL
SNOW AMOUNTS BY MIDNIGHT TONIGHT WILL RANGE FROM ABOUT A HALF INCH
OVER WEST AND SOUTHWEST SECTIONS TO ABOUT AN INCH AND A HALF IN OUR
EAST.
ON SATURDAY...THERE MAY BE SOME LAKE ENHANCEMENT...BUT MOST OF THIS
WILL BE LITTLE MORE THAN FLURRIES ACROSS OUR REGION AND AREA WILL
SHIFT SLOWLY EAST DURING THE DAY AS FLOW BECOMES MORE WESTERLY.
FINALLY MOSTLY CLEAR WEATHER WILL BE THE RULE SATURDAY
NIGHT...SUNDAY AND MOST OF SUNDAY NIGHT. BUT WITH SOME CLOUDS
SPREADING IN TOWARDS DAYBREAK MONDAY. WENT CLOSE TO A MAV/MET
BLEND ON TEMPERATURES MOST PERIODS. BUT THEY MAY BE TAD WARMER
ACROSS OUR NORTHWEST LATE TONIGHT WHERE SOME LAKE EFFECT CLOUDS ARE
LIKELY TO OCCUR.
WINDS GUSTS OF 25 TO 30 MPH ARE POSSIBLE TONIGHT AND SATURDAY AS
PRESSURE GRADIENT SHARPENS ACROSS OUR REGION.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
EXTENDED PERIOD BEGINS WITH A GOOD CHANCE FOR SNOW MONDAY NIGHT
THROUGH EARLY TUESDAY AS ENSEMBLES ALL SHOW UPPER FORCING
ARRIVING BY MONDAY AFTN...AHEAD OF UPPER WAVE. THIS SYSTEM SHOULD
MOVE THROUGH THE AREA MONDAY NIGHT...AND WITH GOOD AGREEMENT FROM
THESE MODELS ON POSITION OF THE FORCING/TIMING HAVE LEFT LIKELY POPS
IN DURING THIS PERIOD. RIGHT NOW IN TERMS OF SNOW AMOUNTS CENTRAL
INDIANA IS NOT LOOKING HIGH AMOUNTS...BUT 1 TO 1.5" IS POSSIBLE ATTM
BASED ON THE MOISTURE FIELDS. PRECIPITATION SHOULD MOVE AWAY FROM
THE AREA LATE TUESDAY HOWEVER MAY HANG ON LONG ENOUGH FOR US TO SEE
SOME -RA MIX WITH -SN LATER DURING THE DAY AS THOSE SURFACE TEMPS
WARM UP.
FORECAST REMAINS DRY UNTIL WED NIGHT WHEN A SOUTHERN STREAM SYSTEM
IS PROGGED TO IMPACT OUR FORECAST AREA...POSSIBLY BRINGING A CHANCE
OF RAIN AND SNOW...THROUGH NOTHING SIGNIFICANT IS EXPECTED AS
MOISTURE AMOUNTS APPEAR QUITE LIMITED. REST OF THE FORECAST PERIOD
REMAINS VERY UNSETTLED AND UNCERTAIN (AS FAR AS THE MODELS GO) WITH
ONE WEAK SYSTEM AFTER ANOTHER PASSING ACROSS THE REGION BRINGING LOW
CHANCES FOR POPS TO THE CWA.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAFS/...
A COLD FRONT FROM THE NORTHWEST WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING....CAUSING ADVERSE (IFR AND POSSIBLY SOME
LIFR) FLYING CONDITIONS AT THE TERMINALS. THIS FRONT WILL DROP
SOUTHEAST OF THE AREA AFTER 06Z.
CONDITIONS HAD BEGUN TO RAPIDLY DETERIORATE ACROSS ALL OF CENTRAL
INDIANA LATE THIS MORNNING. ADJUSTMENTS WERE MADE TO THE TAFS
BASED ON THIS...PUTTING MOST OF THE TERMINALS IN EITHER PREVAILING
OR TEMPO/D IFR. ALSO...BASED ON LATEST OBS AND TRENDS UPSTREAM,
HAVE DOUBTS AS TO WHETHER LAF/IND AND EVEN HUF WILL SEE ANY RAIN
MIX IN SO THIS WAS OMITTED FROM THEIR TAFS (ONLY GOING WITH -SN
ATTM)...WITH HUF POSSIBLY TO FOLLOW. WINDS WILL INCREASE AND SWING
TO THE SOUTHWEST BEFORE FROPA AND AFTER FRONTAL PASSAGE WILL
INCREASE TO AROUND 15 KTS SUSTAINED WITH GUSTS OF 20-30 KTS OUT OF
THE NORTHWEST...AND THIS SHOULD OCCUR ABOUT 22-23Z AT KLAF AND
MOVE TO THE SOUTHEAST FINALLY PASSING THROUGH KBMG AROUND 1Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...NIELD
SHORT TERM...JH
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1213 PM EST FRI FEB 10 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
AN UPPER TROUGH MOVING EAST ACROSS THE CENTRAL AND SOUTHERN
MISSISSIPPI VALLEY WILL SPREAD LIGHT PRECIP INTO OUR REGION BY
AFTERNOON AS AN ARCTIC COLD FRONT OVER THE UPPER MIDWEST MOVES
ACROSS OUR REGION LATE TODAY AND EARLY TONIGHT. ON SATURDAY A COLD
FLOW OF ARCTIC AIR WILL BE ACROSS OUR REGION. SOME LAKE EFFECT
FLURRIES POSSIBLE MAINLY NORTH AND EAST. HIGH PRESSURE OVER THE
NORTHERN THIS WEEKEND WILL MOVE ACROSS OUR REGION LATE SUNDAY AND
EARLY MONDAY. THE COMBINATION OF WARM ADVECTION AND AN UPPER LEVEL
DISTURBANCE WILL BRING PRECIP ACROSS OUR REGION BY LATE MONDAY INTO
TUESDAY.
FARTHER INTO THE EXTENDED...SOME MODELS INDICATE ANOTHER WEAK
DISTURBANCE MAY AFFECT US BY THURSDAY.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE ADJUSTMENTS TO THE FORECAST BASED ON RUC WETBULB
TEMPERATURE PROGS. APPEARS 35F IS A GOOD LINE FOR WHERE SNOW
TRANSITIONS TO RAIN...SO BASED ON THIS HAVE ADJUSTED GRIDS TO
DEPICT LIKELY RAIN OR SNOW SOUTHWEST...LIKELY SNOW-SLIGHT CHANCE
TO CHANCE OF RAIN NORTHEAST OF THERE...AND THEN ALL SNOW ACROSS
THE NORTHEASTERN HALF OF THE FORECAST AREA...ROUGHLY FROM A LAF-
IND-BAK LINE NORTHEAST.
AMOUNTS REMAIN ROUGHLY THE SAME...FROM HALF INCH OR SO IN THE
SOUTHWEST...TO 1 TO AS HIGH AS 2 CENTRAL AND NORTHEAST...WITH
HIGHEST AMOUNTS NEAR MUNCIE.
DROPPED TEMPS SLIGHTLY ALSO BASED ON WETBULB TEMPS AND HOURLY
NUMERICAL GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT WILL BE MOVING THROUGH THIS EVENING AND MODELS HAVE
TRENDED A LITTLE SLOWER IN ENDING PRECIP. MOST OF THIS WILL OCCUR
BETWEEN 00Z AND 06Z AND SHOULD BE PRIMARILY ALL SNOW. WITH
TEMPERATURES DROPPING WELL BELOW FREEZING AND WINDS
INCREASING...THERE SHOULD BE SOME ISSUES WITH SLIPPERY ROADS
TONIGHT. WILL CONTINUE SPECIAL WEATHER STATEMENT ON THIS. TOTAL
SNOW AMOUNTS BY MIDNIGHT TONIGHT WILL RANGE FROM ABOUT A HALF INCH
OVER WEST AND SOUTHWEST SECTIONS TO ABOUT AN INCH AND A HALF IN OUR
EAST.
ON SATURDAY...THERE MAY BE SOME LAKE ENHANCEMENT...BUT MOST OF THIS
WILL BE LITTLE MORE THAN FLURRIES ACROSS OUR REGION AND AREA WILL
SHIFT SLOWLY EAST DURING THE DAY AS FLOW BECOMES MORE WESTERLY.
FINALLY MOSTLY CLEAR WEATHER WILL BE THE RULE SATURDAY
NIGHT...SUNDAY AND MOST OF SUNDAY NIGHT. BUT WITH SOME CLOUDS
SPREADING IN TOWARDS DAYBREAK MONDAY. WENT CLOSE TO A MAV/MET
BLEND ON TEMPERATURES MOST PERIODS. BUT THEY MAY BE TAD WARMER
ACROSS OUR NORTHWEST LATE TONIGHT WHERE SOME LAKE EFFECT CLOUDS ARE
LIKELY TO OCCUR.
WINDS GUSTS OF 25 TO 30 MPH ARE POSSIBLE TONIGHT AND SATURDAY AS
PRESSURE GRADIENT SHARPENS ACROSS OUR REGION.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FORECAST FOCUS IN THE LONG TERM IS ON POTENTIAL FOR SNOW MONDAY
THROUGH TUESDAY. MODELS ARE IN GOOD AGREEMENT EARLY AND THEN DIVERGE
BY WEDNESDAY/THURSDAY. FOR TEMPERATURES THOUGHT THE ALLBLEND
INITIALIZATION CAPTURED THINGS WELL AND MADE NO ADJUSTMENTS. THIS
YIELDED TEMPERATURES NEAR AVERAGE AT THE BEGINNING OF THE LONG TERM
INCREASING TO ABOVE AVERAGE FOR THE MIDDLE THROUGH THE END OF THE
WEEK. FOR POPS DID MAKE SOME ADJUSTMENTS TO ALLBLEND BASED ON MODEL
AGREEMENT OR LACK THEREOF.
MONDAY HIGH PRESSURE WILL BE OVER THE AREA TO START THE DAY...BUT
ECMWF/GFS/GEM ARE SHOWING UPPER FORCING ARRIVING BY MONDAY AFTERNOON
AHEAD OF UPPER WAVE. THE MAJORITY OF THIS FORCING WILL MOVE THROUGH
THE AREA MONDAY NIGHT...AND WITH GOOD AGREEMENT FROM THESE MODELS ON
POSITION OF FORCING AND TIMING AS WELL AS AGREEMENT FROM NEIGHBORING
OFFICES HAVE INCREASED POPS FROM CHANCE TO LOW END LIKELY.
PRECIPITATION SHOULD MOVE OUT FROM WEST TO EAST ON TUESDAY BUT MAY
NOT BE FAST ENOUGH TO BE OUT BY THE AFTERNOON SO MAINTAINED SLIGHT
CHANCE IN THE WEST TO VERY LOW CHANCE POPS IN THE EAST. FOR
PRECIPITATION TYPE SNOW WILL BE THE RULE FROM MONDAY AFTERNOON
THROUGH MONDAY NIGHT. TUESDAY MORNING COULD SEE SOME RAIN MIX IN AND
BY TUESDAY AFTERNOON THE SOUTH COULD SEE LIGHT RAIN IF PRECIPITATION
HASN/T CLEARED OUT. UPPER RIDGING SHOULD BE IN PLACE FOR TUESDAY
NIGHT AND WEDNESDAY SO WENT DRY THEN.
LOW PRECIPITATION CHANCES MOVE BACK IN WEDNESDAY NIGHT WITH THE
POSSIBILITY OF A SURFACE FRONT FORMING JUST SOUTH OF THE AREA.
HOWEVER THIS IS ONLY THE GFS SOLUTION AND THE ECMWF MAINTAINS HIGH
PRESSURE ACROSS THE AREA. FOR WEDNESDAY NIGHT WAS FINE WITH ALLBLEND
POPS OF SLIGHT TO LOW END CHANCE. FOR THURSDAY DECREASED POPS TO LOW
END CHANCE WITH QUITE A BIT OF ENSEMBLE VARIABILITY ON PATTERN AND
GFS/ECMWF SHOWING COMPLETELY DIFFERENT SOLUTIONS /GFS FASTER AND
WETTER WITH UPPER PATTERN/.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAFS/...
A COLD FRONT FROM THE NORTHWEST WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING....CAUSING ADVERSE (IFR AND POSSIBLY SOME
LIFR) FLYING CONDITIONS AT THE TERMINALS. THIS FRONT WILL DROP
SOUTHEAST OF THE AREA AFTER 06Z.
CONDITIONS HAD BEGUN TO RAPIDLY DETERIORATE ACROSS ALL OF CENTRAL
INDIANA LATE THIS MORNNING. ADJUSTMENTS WERE MADE TO THE TAFS
BASED ON THIS...PUTTING MOST OF THE TERMINALS IN EITHER PREVAILING
OR TEMPO/D IFR. ALSO...BASED ON LATEST OBS AND TRENDS UPSTREAM,
HAVE DOUBTS AS TO WHETHER LAF/IND AND EVEN HUF WILL SEE ANY RAIN
MIX IN SO THIS WAS OMITTED FROM THEIR TAFS (ONLY GOING WITH -SN
ATTM)...WITH HUF POSSIBLY TO FOLLOW. WINDS WILL INCREASE AND SWING
TO THE SOUTHWEST BEFORE FROPA AND AFTER FRONTAL PASSAGE WILL
INCREASE TO AROUND 15 KTS SUSTAINED WITH GUSTS OF 20-30 KTS OUT OF
THE NORTHWEST...AND THIS SHOULD OCCUR ABOUT 22-23Z AT KLAF AND
MOVE TO THE SOUTHEAST FINALLY PASSING THROUGH KBMG AROUND 1Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...NIELD
SHORT TERM...JH
LONG TERM....CP
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1140 AM EST FRI FEB 10 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
AN UPPER TROUGH MOVING EAST ACROSS THE CENTRAL AND SOUTHERN
MISSISSIPPI VALLEY WILL SPREAD LIGHT PRECIP INTO OUR REGION BY
AFTERNOON AS AN ARCTIC COLD FRONT OVER THE UPPER MIDWEST MOVES
ACROSS OUR REGION LATE TODAY AND EARLY TONIGHT. ON SATURDAY A COLD
FLOW OF ARCTIC AIR WILL BE ACROSS OUR REGION. SOME LAKE EFFECT
FLURRIES POSSIBLE MAINLY NORTH AND EAST. HIGH PRESSURE OVER THE
NORTHERN THIS WEEKEND WILL MOVE ACROSS OUR REGION LATE SUNDAY AND
EARLY MONDAY. THE COMBINATION OF WARM ADVECTION AND AN UPPER LEVEL
DISTURBANCE WILL BRING PRECIP ACROSS OUR REGION BY LATE MONDAY INTO
TUESDAY.
FARTHER INTO THE EXTENDED...SOME MODELS INDICATE ANOTHER WEAK
DISTURBANCE MAY AFFECT US BY THURSDAY.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE ADJUSTMENTS TO THE FORECAST BASED ON RUC WETBULB
TEMPERATURE PROGS. APPEARS 35F IS A GOOD LINE FOR WHERE SNOW
TRANSITIONS TO RAIN...SO BASED ON THIS HAVE ADJUSTED GRIDS TO
DEPICT LIKELY RAIN OR SNOW SOUTHWEST...LIKELY SNOW-SLIGHT CHANCE
TO CHANCE OF RAIN NORTHEAST OF THERE...AND THEN ALL SNOW ACROSS
THE NORTHEASTERN HALF OF THE FORECAST AREA...ROUGHLY FROM A LAF-
IND-BAK LINE NORTHEAST.
AMOUNTS REMAIN ROUGHLY THE SAME...FROM HALF INCH OR SO IN THE
SOUTHWEST...TO 1 TO AS HIGH AS 2 CENTRAL AND NORTHEAST...WITH
HIGHEST AMOUNTS NEAR MUNCIE.
DROPPED TEMPS SLIGHTLY ALSO BASED ON WETBULB TEMPS AND HOURLY
NUMERICAL GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT WILL BE MOVING THROUGH THIS EVENING AND MODELS HAVE
TRENDED A LITTLE SLOWER IN ENDING PRECIP. MOST OF THIS WILL OCCUR
BETWEEN 00Z AND 06Z AND SHOULD BE PRIMARILY ALL SNOW. WITH
TEMPERATURES DROPPING WELL BELOW FREEZING AND WINDS
INCREASING...THERE SHOULD BE SOME ISSUES WITH SLIPPERY ROADS
TONIGHT. WILL CONTINUE SPECIAL WEATHER STATEMENT ON THIS. TOTAL
SNOW AMOUNTS BY MIDNIGHT TONIGHT WILL RANGE FROM ABOUT A HALF INCH
OVER WEST AND SOUTHWEST SECTIONS TO ABOUT AN INCH AND A HALF IN OUR
EAST.
ON SATURDAY...THERE MAY BE SOME LAKE ENHANCEMENT...BUT MOST OF THIS
WILL BE LITTLE MORE THAN FLURRIES ACROSS OUR REGION AND AREA WILL
SHIFT SLOWLY EAST DURING THE DAY AS FLOW BECOMES MORE WESTERLY.
FINALLY MOSTLY CLEAR WEATHER WILL BE THE RULE SATURDAY
NIGHT...SUNDAY AND MOST OF SUNDAY NIGHT. BUT WITH SOME CLOUDS
SPREADING IN TOWARDS DAYBREAK MONDAY. WENT CLOSE TO A MAV/MET
BLEND ON TEMPERATURES MOST PERIODS. BUT THEY MAY BE TAD WARMER
ACROSS OUR NORTHWEST LATE TONIGHT WHERE SOME LAKE EFFECT CLOUDS ARE
LIKELY TO OCCUR.
WINDS GUSTS OF 25 TO 30 MPH ARE POSSIBLE TONIGHT AND SATURDAY AS
PRESSURE GRADIENT SHARPENS ACROSS OUR REGION.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FORECAST FOCUS IN THE LONG TERM IS ON POTENTIAL FOR SNOW MONDAY
THROUGH TUESDAY. MODELS ARE IN GOOD AGREEMENT EARLY AND THEN DIVERGE
BY WEDNESDAY/THURSDAY. FOR TEMPERATURES THOUGHT THE ALLBLEND
INITIALIZATION CAPTURED THINGS WELL AND MADE NO ADJUSTMENTS. THIS
YIELDED TEMPERATURES NEAR AVERAGE AT THE BEGINNING OF THE LONG TERM
INCREASING TO ABOVE AVERAGE FOR THE MIDDLE THROUGH THE END OF THE
WEEK. FOR POPS DID MAKE SOME ADJUSTMENTS TO ALLBLEND BASED ON MODEL
AGREEMENT OR LACK THEREOF.
MONDAY HIGH PRESSURE WILL BE OVER THE AREA TO START THE DAY...BUT
ECMWF/GFS/GEM ARE SHOWING UPPER FORCING ARRIVING BY MONDAY AFTERNOON
AHEAD OF UPPER WAVE. THE MAJORITY OF THIS FORCING WILL MOVE THROUGH
THE AREA MONDAY NIGHT...AND WITH GOOD AGREEMENT FROM THESE MODELS ON
POSITION OF FORCING AND TIMING AS WELL AS AGREEMENT FROM NEIGHBORING
OFFICES HAVE INCREASED POPS FROM CHANCE TO LOW END LIKELY.
PRECIPITATION SHOULD MOVE OUT FROM WEST TO EAST ON TUESDAY BUT MAY
NOT BE FAST ENOUGH TO BE OUT BY THE AFTERNOON SO MAINTAINED SLIGHT
CHANCE IN THE WEST TO VERY LOW CHANCE POPS IN THE EAST. FOR
PRECIPITATION TYPE SNOW WILL BE THE RULE FROM MONDAY AFTERNOON
THROUGH MONDAY NIGHT. TUESDAY MORNING COULD SEE SOME RAIN MIX IN AND
BY TUESDAY AFTERNOON THE SOUTH COULD SEE LIGHT RAIN IF PRECIPITATION
HASN/T CLEARED OUT. UPPER RIDGING SHOULD BE IN PLACE FOR TUESDAY
NIGHT AND WEDNESDAY SO WENT DRY THEN.
LOW PRECIPITATION CHANCES MOVE BACK IN WEDNESDAY NIGHT WITH THE
POSSIBILITY OF A SURFACE FRONT FORMING JUST SOUTH OF THE AREA.
HOWEVER THIS IS ONLY THE GFS SOLUTION AND THE ECMWF MAINTAINS HIGH
PRESSURE ACROSS THE AREA. FOR WEDNESDAY NIGHT WAS FINE WITH ALLBLEND
POPS OF SLIGHT TO LOW END CHANCE. FOR THURSDAY DECREASED POPS TO LOW
END CHANCE WITH QUITE A BIT OF ENSEMBLE VARIABILITY ON PATTERN AND
GFS/ECMWF SHOWING COMPLETELY DIFFERENT SOLUTIONS /GFS FASTER AND
WETTER WITH UPPER PATTERN/.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAFS/...
1600Z UPDATE...CONDITIONS HAVE IN THE LAST HOUR BEGUN TO RAPIDLY
DETERIORATE ACROSS ALL OF CENTRAL INDIANA. HAVE MADE ADJUSTMENTS
TO TAFS BASED ON THIS...PUTTING MOST OF THE TERMINALS IN EITHER
PREVAILING OR TEMPO/D IFR. ALSO BASED ON LATEST OBS AND TRENDS
UPSTREAM, HAVE DOUBTS AS TO WHETHER LAF AND IND WILL SEE ANY RAIN
MIX IN SO THIS WAS OMITTED FROM THEIR TAFS...WITH HUF POSSIBLY TO
FOLLOW. PREVIOUS DISCS FOLLOW....
1430Z UPDATE...AVIATION FORECAST APPEARS TO BE IN GOOD SHAPE BASED
ON LATEST TRENDS. DID NOT NEED TO MAKE MANY ADJUSTMENTS TO THE
TAFS ATTM. PREVIOUS DISC FOLLOWS...
A LOW PRESSURE SYSTEM FROM THE SOUTH AND A COLD FRONT FROM THE
NORTHWEST WILL BOTH MOVE ACROSS THE AREA TODAY AND CREATE ADVERSE
FLYING CONDITIONS AT THE SITES. STARTING OUT WITH VFR CEILINGS WILL
DETERIORATE TO MVFR BY MIDDAY AND FINALLY IFR FOR AWHILE THIS
EVENING. WINDS WILL INCREASE AND SWING TO THE SOUTHWEST BEFORE
FRONTAL PASSAGE AND AFTER FRONTAL PASSAGE WILL INCREASE TO AROUND 15
KTS SUSTAINED WITH GUSTS OF 20-30 KTS OUT OF THE NORTHWEST...AND
THIS SHOULD OCCUR ABOUT 22-23Z AT KLAF AND MOVE TO THE SOUTHEAST
FINALLY PASSING THROUGH KBMG AROUND 1Z. LIGHT SNOW WILL BE POSSIBLE
BY LATE MORNING...CHANGING TO A RAIN/SNOW MIX THIS AFTERNOON AND
FINALLY CHANGING OVER TO SNOW THIS EVENING AROUND FRONTAL PASSAGE.
WITH THE HIGHER WINDS THIS COULD BRING HEAVIER SNOW AND COULD SEE
IFR VISIBILITIES WITH THE LAST FEW HOURS OF THE SNOW AS WELL. SNOW
SHOULD COME TO AN END BY 6Z OR SO AND CLOUD COVER SHOULD IMPROVE TO
MVFR BUT WIND GUSTS WILL CONTINUE THROUGH THE NIGHT/MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...NIELD
SHORT TERM...JH
LONG TERM....CP
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 PM CST FRI FEB 10 2012
.SYNOPSIS...
12Z UA ANALYSIS HAS A COLD FRONT FROM THE MACKINAC STRAITS INTO
NORTHERN KANSAS WITH TROFS FROM THE MID ATLANTIC BACK INTO THE
PLAINS. SATELLITE AND RADAR TRENDS THROUGH MID AFTERNOON SHOWS AREAS
OF LIGHT SNOW AND SNOW SHOWERS ACROSS THE WESTERN GREAT LAKES WITH
CLEARING SKIES IN MINNESOTA.
18Z SFC ANALYSIS HAS A LOW JUST EAST OF KMKG AND ANOTHER JUST
NORTHEAST OF KORD. THE ARCTIC FRONT RAN FROM THE SECOND LOW
SOUTHWEST INTO NORTHERN TEXAS. DEW POINTS WERE IN THE 20S AND 30S
AHEAD AND IMMEDIATELY BEHIND THE FRONT WITH SINGLE DIGITS ABOVE AND
BELOW ZERO ACROSS THE NORTHERN PLAINS.
&&
.SHORT TERM...TONIGHT AND SATURDAY...
RUC TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE DOING A
REASONABLY GOOD JOB OF DEPICTING THE CURRENT CLOUD COVER ACROSS THE
AREA. SNOW SHOWERS/FLURRIES WILL CONTINUE THROUGH THE AFTERNOON WITH
MOST SNOW SHOWERS DISSIPATING WITH SUNSET. STRONG CYCLONIC FLOW AND
VORT MAXES ROTATING THROUGH THE AREA SHOULD PROLONG THE FLURRIES
INTO THE EARLY EVENING OVER ROUGHLY THE EASTERN HALF OF THE CWFA.
GENERAL ACCUMULATIONS SHOULD RANGE FROM A TRACE TO A DUSTING.
A FEW HOURS AGO THE RUC WAS INDICATING CLEARING WOULD OCCUR FROM THE
NORTHWEST AFTER MID EVENING AND THEN TAKE MOST OF THE NIGHT TO CLEAR
OUT EAST OF THE MISSISSIPPI. HOWEVER...A NEW CLEAR AREA HAS
DEVELOPED IN AN AREA OF SUBSIDENCE ACROSS NORTHERN WISCONSIN. RUC
TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE NOW
SUGGESTING THE CWFA MAY SEE CLEARING STARTING FROM THE NORTHWEST AND
WEST AFTER MID-EVENING AND ALSO FROM THE NORTHEAST. IF THIS DOES
OCCUR THEN ROUGHLY THE SOUTHEAST QUADRANT OF THE CWFA WOULD BE THE
LAST TO CLEAR OUT AFTER MIDNIGHT.
TEMPERATURES WILL BE INTERESTING. AREAS THAT CLEAR OUT SOONER WILL
DROP QUICKLY DUE TO THE CAA THAT WILL CONTINUE OVERNIGHT. THE FACT
THAT WINDS WILL NOT DECOUPLE FROM THE BOUNDARY LAYER WILL BE WHAT
KEEPS LOWS ABOVE ZERO. FAVORED COLD AREAS IN THE WAPSI AND SAUK
VALLEYS MAY APPROACH ZERO IN SPITE OF THE WINDS. THE WIND AND
TEMPERATURES WILL DROP WIND CHILLS WELL BELOW ZERO BUT ARE EXPECTED
TO REMAIN JUST ABOVE ADVISORY CRITERIA.
SATURDAY WILL BE A COLD BRISK DAY. ARCTIC HIGH PRESSURE BUILDING
INTO THE AREA WILL RESULT IN SUNNY SKIES BUT WIND CHILLS ARE
EXPECTED TO REMAIN BELOW ZERO FOR MUCH OF THE MORNING. MAX
TEMPERATURES WILL STRUGGLE TO GET INTO THE UPPER TEENS AND LOWER 20S
BY MID AFTERNOON.
..08..
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
A HIGH PRESSURE RIDGE CENTERED OVER WESTERN IOWA SATURDAY EVENING
WILL MOVE EAST THROUGH THE MID MISSISSIPPI RIVER VALLEY BY MONDAY
MORNING. TEMPERATURES WILL BE THE MAIN CONCERN SATURDAY NIGHT AND
SUNDAY WITH THE RIDGE AXIS JUST WEST OF THE CWFA. THERE SHOULD BE
ENOUGH OF A PRESSURE GRADIENT TO KEEP WINDS FROM DECOUPLING. THE
WIND ALONG ALONG WITH BARE GROUND SHOULD KEEP MIN TEMPS SATURDAY
NIGHT ABOVE ZERO. ALTHOUGH A SMALL PART OF THE SOUTHWEST CWFA COULD
SLIP BELOW ZERO SINCE VISIBLE SATELLITE IMAGERY SHOWS SOME SNOW
COVER NOSING INTO THE AREA. TEMPS ARE EXPECTED TO REBOUND INTO THE
20S FOR SUNDAY.
PRECIPITATION CHANCES ENTER THE PICTURE SUNDAY NIGHT THROUGH TUESDAY
AS RETURN FLOW SETS UP BEHIND THE RETREATING LOW LEVEL RIDGE AND A
SHORT WAVE MOVES FROM THE NORTHERN PLAINS THROUGH THE MID AND UPPER
MISSISSIPPI VALLEY. THE GFS/NAM ARE THE MOST BULLISH ON PRECIP
DURING THIS PERIOD...GENERATING ABOUT 2 TO 3 TENTHS OF INCH WATER
EQUIVALENT WHILE THE ECMWF PRODUCES 1 TO 2 TENTHS. TEMPERATURES
WILL BE COLD ENOUGH THROUGH THE EVENT FOR ALL SNOW. KEPT AMOUNTS
IN THE 1 TO 3 INCH RANGE WITH THE HIGHEST AMOUNTS WEST AND NORTH.
IF THE GFS VERIFIES THEN THE 3 INCH AMOUNTS SHOULD BE REALIZED WHILE
THE ECMWF WOULD SUPPORT AMOUNTS CLOSER TO AN INCH. THE MEASURABLE
SNOW SHOULD END MONDAY EVENING WITH SOME FLURRIES LINGERING INTO
TUESDAY...SPECIALLY EAST OF THE MISSISSIPPI RIVER.
MODELS CONTINUE TO SHOW A SPLIT FLOW REGIME THROUGH THE REST OF THE
FORECAST PERIOD WITH TEMPERATURES RETURNING TO NEAR OR JUST ABOVE
NORMAL. MOST OF THE SOLUTIONS MOVE A NORTHERN STREAM TROF THROUGH
THE REGION THURSDAY OR FRIDAY BUT KEEP THE SYSTEM UN-PHASED AND
MOISTURE STARVED. THE LONE EXCEPTION IS THE 12Z ECMWF WHICH PHASES
THE TROF WITH THE SOUTHERN STREAM...RESULTING IN A MODERATE PRECIP
EVENT FOR THE REGION. AT THIS POINT THERE IS LOW CONFIDENCE IN THE
EXTENDED PROGS SO KEPT SOME SLIGHT CHANCE POPS IN FOR ALL OR PART OF
THE AREA WEDNESDAY THROUGH FRIDAY. ..DLF..
&&
.AVIATION...
DAYTIME HEATING IS ALLOWING CIGS TO RISE BUT MVFR CONDITIONS REMAIN
COMMON WITH POCKETS OF VFR. CONDITIONS TO SLOWLY IMPROVE TO VFR CIGS
AFT 00Z/11 WITH CLR SKIES DVLPG 06Z-12Z/11. CONVECTIVE SHSN AND -SN
WILL TAPER TO FLURRIES BY 00Z/11 AND END BY 03Z/11. WINDS WILL
SLOWLY DECREASE AFT SUNSET BUT ARE EXPECTED TO REMAIN ABV 12 KTS.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1056 AM CST FRI FEB 10 2012
.UPDATE...
SATELLITE TRENDS SHOW CLOUDS DEVELOPING BACK TO THE SOUTHWEST
ACROSS EASTERN MINNESOTA WITH FLURRIES AND SNOW SHOWERS BECOMING
MORE WIDESPREAD ON AREA RADARS.
RUC TRENDS AND THE 12Z WRF RUN SHOW THE MODELS HAVE SOME IDEA
ABOUT THE CLOUDS USING THE 900-950MB RH LAYER AND 0.5-1.0KM RH
LAYER. SATELLITE TRENDS ALONG WITH INPUTS FROM THE RUC/WRF
INDICATE CLOUDS WILL REMAIN ACROSS THE AREA TODAY AND INTO THE
EVENING. CONCEPTUALLY...THIS MAKES SENSE SINCE THERE IS STRONG
CYCLONIC FLOW ALOFT WITH TWO MORE VORT MAXES THAT WILL ROTATE
THROUGH THE AREA. STRONG SUBSIDENCE BEHIND THE SECOND VORT MAX
SHOULD ALLOW CLEARING TO DEVELOP LATE THIS EVENING OUT WEST AND
SPREAD SOUTH/EAST AFTER MIDNIGHT. BASED ON THE RUC/WRF TRENDS
CLOUDS WILL PROBABLY LINGER IN THE FAR EAST UNTIL NEARLY SUNRISE.
BASED ON SFC REPORTS...POPS HAVE BEEN PULLED FURTHER WEST FOR LATE
THIS MORNING AND AFTERNOON.
MAX TEMPERATURES HAVE ALREADY OCCURRED AND THE CAA WILL RESULT IN
TEMPERATURES DOING A SLOW FALL FOR THE REMAINDER OF THE DAY.
AN UPDATED FCST REFLECTING THIS HAS ALREADY BEEN SENT.
..08..
&&
.AVIATION...
SATELLITE TRENDS COMBINED WITH TRENDS FROM THE RUC MODEL INDICATE
MVFR CIGS WILL CONTINUE PAST 00Z/11 FOR ALL TAF SITES. SHSN ARE
MOST LIKELY TO BE SEEN AT KDBQ/KMLI WITH FLURRIES AT KCID/KBRL.
THE SHSN MAY BRIEFLY DROP VSBYS TO MVFR OR IFR IF THEY IMPACT A
TAF SITE. VFR CONDITIONS SHOULD DVLP AT ALL TAF SITES AFT 06Z/11.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 PM MST FRI FEB 10 2012
.SYNOPSIS...
ISSUED AT 222 PM MST FRI FEB 10 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE SCALE
TROUGH ACROSS SOUTHERN CANADA EXTENDING SOUTH ACROSS THE GREAT
LAKES AND NORTHERN PLAINS. AT THE SURFACE THE COLD FRONT THAT
PASSED THROUGH THE CWA THIS MORNING HAS STALLED ALONG THE W/SW
PART OF THE CWA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 222 PM MST FRI FEB 10 2012
TONIGHT THROUGH EARLY SATURDAY...A FRONTAL BOUNDARY WILL REMAIN
NEARLY STATIONARY ACROSS THE HIGHER TERRAIN OF THE CENTRAL HIGH
PLAINS. EXPECT AREAS OF LIGHT SNOW TO DEVELOP OVERNIGHT IN THE
VICINITY OF THIS BOUNDARY AS WEAK WAVES MOVE THROUGH THE NORTHWEST
FLOW ALOFT. THERE IS A SLIGHT CHANCE OF SOME FREEZING FOG IN VERY
CLOSE PROXIMITY TO THE FRONT OVERNIGHT OVER FAR EASTERN COLORADO
WHERE THE LOW CLOUDS WILL INTERSECT THE TERRAIN. HAVE TRIMMED THE
AREAS OF FREEZING FOG DOWN SOME...BUT HAVE KEPT IT IN THERE. THE
AIRMASS BEGINS DRYING OUT OVERNIGHT AS THE COLD AIR CONTINUES TO
PUSH FURTHER INTO THE REGION...SO HAVE DECREASED PRECIPITATION AND
CLOUD COVER FROM NORTHEAST TO SOUTHWEST OVERNIGHT THROUGH EARLY
SATURDAY MORNING.
LOCKHART
SATURDAY THROUGH SATURDAY NIGHT...WITH BAROCLINIC ZONE AND
LINGERING H85-H7 FRONTOGENSIS ACROSS THE WESTERN CWA...CANT RULE
OUT CONTINUED LIGHT SNOW THROUGH MID AFTERNOON SATURDAY. AIRMASS
CONTINUES TO DRY OUT THROUGH MIDDAY FROM THE NORTHEAST...SO I HAVE
KEPT CHANCE MENTION LIMITED TO FAR WESTERN CWA THROUGH 21Z. WITH
LINGERING CLOUD COVER AND VERY COLD AIRMASS IN PLACE TEMPERATURES
WILL STRUGGLE TO WARM MUCH. CURRENT FORECAST ALLOWS FOR SOME
DIURNAL WARMING WITH TEMPS IN THE MID TEENS TO LOW 20S ACROSS MUCH
OF THE CWA...AND AROUND 12 NEAR MCCOOK. CONSIDERING THE COLD
AIRMASS ALOFT AND LINGERING LOW CLOUDS...THIS MAY BE TOO
OPTIMISTIC. MODEL SOUNDINGS STILL SHOWING WARM LAYER ABOVE H85
ACROSS THE WESTERN PARTS OF THE CWA SATURDAY NIGHT...WITH SHALLOW
COLD NEAR SATURATED LAYER BELOW THIS. WITH UPSLOPE STILL
PERSISTING ALONG BAROCLINIC ZONE IN EASTERN COLORADO CANT RULE
OUT FREEZING FOG OR FREEZING DRIZZLE THROUGH EARLY SUNDAY MORNING.
I SAW NO NEED TO MAKE ANY MAJOR CHANGES TO PREVIOUS FORECAST WHICH
ALREADY HAD AREAS OF FREEZING FOG/DRIZZLE SATURDAY NIGHT THROUGH
EARLY SUNDAY MORNING.
DR
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 222 PM MST FRI FEB 10 2012
SUNDAY THROUGH MONDAY...SHORTWAVE RIDGING SHOULD KEEP CONDITIONS
DRY DURING THE DAY SUNDAY...WITH TEMPERATURES MODERATING ALOFT
FROM THE WEST. LINGERING CLOUD COVER WILL STILL LIMIT THE AMOUNT
OF DIURNAL WARMING AT THE SURFACE...SO TEMPS WILL LIKELY STILL
REMAIN BELOW FREEZING IN THE E/NE HALF OF THE CWA. A SHORTWAVE
TROUGH WILL MOVE IN THE REGION BY SUNDAY NIGHT. THIS SYSTEM DOES
NOT APPEAR TO BE VERY WELL ORGANIZED WITH MAIN H25-H3 JET OVER
OKLAHOMA PANHANDLE. THERE STILL APPEARS TO BE ENOUGH LIFT/MOISTURE
THAT I CANT RULE OUT SNOW SUNDAY NIGHT THROUGH MONDAY MORNING. BY
MONDAY AFTERNOON SHORTWAVE RIDGING BUILDS BACK OVER CWA.
TUESDAY THROUGH FRIDAY...SPLIT FLOW DOMINATES THE PATTERN
THROUGH THE REMAINING EXTENDED PERIODS. WHILE GUIDANCE IN MODERATE
AGREEMENT ON THE OVERALL PATTER...THERE IS VERY POOR RUN TO RUN
CONSISTENCY IN REGARDS TO THE HANDLING OF SMALLER SCALE FEATURES.
BEST CHANCE FOR PRECIP STILL APPEARS TO BE TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT AS A SERIES OF SHORTWAVE TROUGHS MOVE THROUGH THE
PLAINS. POSITION/TIMING OF THESE FEATURES HAS BEEN ALL OVER THE
PLACE THE LAST FEW DAYS. THE 00Z ECMWF AND 00Z/12 GFS WERE
STARTING TO SHOW SIMILAR TRENDS FOR PRECIP OVER OUR CWA...WITH
LIGHT SNOW PREDOMINATELY OVER THE SOUTHERN HALF OF THE CWA QUICKLY
EXITING THE REGION BY TUESDAY AFTERNOON/WEDNESDAY NIGHT. THE 12Z
ECMWF AND GEM ARE BOTH MUCH MORE BULLISH WITH THIS SYSTEM
PRODUCING A CLOSED H5 CENTER AND MUCH MORE PRECIPITATION...WITH
THE 12Z ECMWF FURTHER NORTH AND LINGERS PRECIP THROUGH THURSDAY.
THIS IS SIGNIFICANT DEVIATION FROM PREVIOUS RUN AND ENSEMBLE DATA.
CONFIDENCE IS PRETTY LOW RIGHT NOW IN ANY PARTICULAR SOLUTION AT
THIS POINT CONSIDERING THE CHAOTIC NATURE OF THIS TYPE OF PATTER.
I KEPT THE FORECAST ON THE CONSERVATIVE END OF THE MODEL
SPREAD...WITH SLIGHT CHANCE POPS TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT. TEMPERATURES THROUGH THIS PERIOD SHOULD REMAIN SLIGHTLY
BELOW NORMAL WITH HIGHS IN THE UPPER 30S/LOW 40S.
DR
&&
.AVIATION...
1226 PM MST FRI FEB 10 2012
AREAS OF LOW CLOUDS HAVE BECOME LESS EXTENSIVE THROUGH THE
MORNING...BUT ARE EXPECTED TO RETURN OVERNIGHT ALONG WITH A
POSSIBILITY OF LIGHT SNOW IN THE VICINITY OF A COLD FRONT DRAPED
ACROSS THE CENTRAL HIGH PLAINS. CHANCES OF LIGHT SNOW AND LOWER
FLIGHT CATEGORIES WILL BE GREATER AT KGLD IN CLOSER PROXIMITY TO
THE FRONT.
VFR CONDITIONS WILL CONTINUE AT BOTH KGLD AND KMCK THROUGH 00Z.
AFTER 00Z...EXPECT LOW CLOUDS AND LOWER VISIBILITIES TO BECOME
MORE EXTENSIVE AS AREAS OF LIGHT SNOW DEVELOP AND PERSIST THROUGH
ABOUT 06Z IN THE VICINITY OF THE FRONTAL BOUNDARY THAT HAS STALLED
OVER EASTERN COLORADO. KMCK WILL SEE MVFR CONDITIONS WHILE KGLD
WILL BE MVFR WITH OCCASIONAL IFR WITH LIGHT SNOW THROUGH ABOUT
12Z. KMCK WILL IMPROVE TO VFR CONDITIONS AGAIN BY 12Z WHILE KGLD
WILL BE SLOWER TO IMPROVE WITH MVFR CONDITIONS AFTER ABOUT 14Z.
LOCKHART
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
411 PM EST FRI FEB 10 2012
.Short Term (Today and Tonight)...
Updated at 317 PM EST Feb 10 2012
First in a series of mid-level wave continues to push eastward into
the lower Ohio Valley this afternoon. Out ahead of this feature,
widespread precipitation shield has been affecting southern Indiana
and central Kentucky this afternoon. Colder thermal profiles across
the north have resulted in precipitation remaining in the form of
snow. However, across southern Kentucky, slightly warmer air aloft
has worked into that region which has resulted in a mix of rain
and/or just plain rain in areas down around Bowling Green and
Glasgow. This band of precipitation continues to head east and will
likely clear the I-65 corridor by 5PM EST and the Bluegrass region
by 7-8 PM tonight. Temperatures this afternoon have warmed into the
upper 30s in the west and with lower 30s in the east. Temperatures
have been taking a dip when the snow bands have moved through...then
have rebounded by a couple of degrees once the precipitation had
ended. For the remainder of the afternoon...we expect temperatures
to remain close to their current values and actually rise a degree
or two once the precipitation has ended as southerly flow attempts
to bring a little warmer air into the area ahead of the approaching
cold front to the northwest of the region. Snowfall accumulations
of a dusting or so will be possible with this afternoon snow
activity...but do not be surprised to see it melt rather quickly
once the precipitation ends. With temps expected to remain above
freezing this afternoon and this evening...am not anticipating much
in the way of travel problems for the afternoon rush and for evening
activities.
For Tonight, the next weather feature will be a strong cold front
that will surge through the region. Currently the front out to our
west near St. Louis. The front has been moving a bit slower than
the models had been forecasting an it is expected to hit our area a
little later than previously forecast. As the front approaches,
temperatures will likely rise slightly and we`ll see a return of
snow showers. The front looks to pass through the I-65 corridor
between 11P-12A EST tonight and then through the I-75 corridor by
2-3AM. Colder air will quickly rush in behind the front and
temperatures will fall into the lower 20s by sunrise on Saturday.
The latest HRRR, our local Hi-Res ARW WRF, and RUC data all show
snow shower activity occurring ahead and behind the front. Vertical
sounding profiles actually have a bit of a convective look to them
and I would not be surprised to see more of a snow shower/snow
squall type of activity to develop later tonight. In addition, the
pressure gradient will really tighten up and winds of 15-20 MPH with
gusts up to 30 MPH will be possible. These snow showers will be the
ones that bring the accumulating snow to the region. The snow
combined with temperatures falling into the lower 20s will result in
slick spots developing later tonight. Therefore we will leave the
current winter weather advisory intact...though much of the expected
snowfall and hazardous travel conditions will be delayed until later
tonight and into Saturday morning.
The front will continue to surge eastward on Saturday and
precipitation will end from west to east during the morning hours.
The models are trying to develop a fetch off of Lake Michigan.
However, the models have been often too aggressive with these during
this winter. Nonetheless...some snow shower activity looks to
persist into the morning hours on Saturday and that will likely add
a little more accumulation over in the Bluegrass region. Skies will
likely remain mostly cloudy through much of the day with
temperatures remaining in the 20s. Surface winds will remain
elevated during the day with winds of 10-20 MPH and gusts up to 25
MPH or so. This will keep wind chills down in the single digits at
times on Saturday.
As far as snowfall accumulations...the consensus guidance suggests
around an inch of accumulation for areas generally north of the WK
and BG Parkways. Little accumulation is expected in the far south
and southwest where a 1/2 inch or less will be possible. Highest
accumulations are going to be in the northeast generally east of
U.S. 27 where 1-2 inches of snowfall will be possible by the time
precipitation comes to an end on Saturday.
.Long Term (Saturday Night - Friday)...
Updated at 300 PM EST Feb 10 2012
1040mb high pressure will be over the central Plains Saturday night,
with an equally significant low off the New England coast. The
gradient in between will mean northwesterly winds that will just
start to weaken some as the night progresses. By the day Sunday, the
high will move to around Arkansas, making the strongest winds over
the Bluegrass and weaker across the southwest forecast area.
Temperatures will remain chilly however, with readings only getting
up to around freezing for highs. Wind chills Sunday morning again
look to be in the single digits for most of the area.
The next weather system to impact the region still looks to be
Monday night. Multiple waves within a strengthening southwesterly
flow will allow for precip all along the MS river valley Monday
afternoon and expect this moisture to advect east for the night.
Given forecast temperatures, expect at least a wintry mix for the
night, if not all snow for the north. By midnight, most of the
region should be into light to moderate snow. We could have another
advisory level event over southern Indiana with still some potential
over norther central Kentucky, but it is too early to be that
specific.
The difference with this system, compared to tonight`s snows, will
be that it looks to be followed by some warming for midweek. Models
are still not handling the longer term that well, so do not have
high confidence at this point. The 12Z GFS had a vortmax cross the
region Wednesday that was not in the previous forecast. the 00Z
ECMWF and now the 12Z have hinted at this as well, but there is not
much moisture associated with the impulse. Conversely, the system
that was expected for Thursday has now backed off as well in the 12Z
GFS, but the new ECMWF continues with a large storm system moving
into the midwest. Given such run-to-run inconsistency, will keep in
some precip chances each day, though with lower pops. Also, have
leaned more towards the precip type as rain, with highs into the 50s
Wednesday through Friday.
&&
.Aviation (21Z TAF Issuance)...
Updated at 410 PM EST Feb 10 2012
Given the recent radar trends we have updated the TAF forecasts for
this evening. Mid-level trough axis to the west is forcing the
current precipitation across southern Indiana and central Kentucky.
This precipitation shield will continue to head to the east and will
exit the terminals in the next hour or so. Behind the precipitation
shield...cigs will likely remain MVFR with VFR visibilities.
Precipitation will redevelop later this evening as a strong cold
front pushes in from the northwest. Based on the current data...the
front should push through KSDF and KBWG around 11/03-05Z and then
through KLEX around 11/05-07Z. Snow showers and snow squalls are
likely to develop in advance and just behind the frontal boundary.
This will likely result in MVFR vsbys and cigs as the snow showers
move through...though I can`t rule out some tempo IFR conditions if
a heavier snow shower or squall impacts the terminal. Winds will
shift from the SW to the NW after frontal passage and winds of
12-18kts sustained and gusts of 24-28kts being possible later
tonight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
INZ076>078-083-084-089>092.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR INZ079.
KY...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
KYZ023>030-053>057-061>067-070>078-081-082.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR KYZ031>043-
045>049.
$$
Short Term.......MJ
Long Term........RJS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
318 PM EST FRI FEB 10 2012
.Short Term (Today and Tonight)...
Updated at 317 PM EST Feb 10 2012
First in a series of mid-level wave continues to push eastward into
the lower Ohio Valley this afternoon. Out ahead of this feature,
widespread precipitation shield has been affecting southern Indiana
and central Kentucky this afternoon. Colder thermal profiles across
the north have resulted in precipitation remaining in the form of
snow. However, across southern Kentucky, slightly warmer air aloft
has worked into that region which has resulted in a mix of rain
and/or just plain rain in areas down around Bowling Green and
Glasgow. This band of precipitation continues to head east and will
likely clear the I-65 corridor by 5PM EST and the Bluegrass region
by 7-8 PM tonight. Temperatures this afternoon have warmed into the
upper 30s in the west and with lower 30s in the east. Temperatures
have been taking a dip when the snow bands have moved through...then
have rebounded by a couple of degrees once the precipitation had
ended. For the remainder of the afternoon...we expect temperatures
to remain close to their current values and actually rise a degree
or two once the precipitation has ended as southerly flow attempts
to bring a little warmer air into the area ahead of the approaching
cold front to the northwest of the region. Snowfall accumulations
of a dusting or so will be possible with this afternoon snow
activity...but do not be surprised to see it melt rather quickly
once the precipitation ends. With temps expected to remain above
freezing this afternoon and this evening...am not anticipating much
in the way of travel problems for the afternoon rush and for evening
activities.
For Tonight, the next weather feature will be a strong cold front
that will surge through the region. Currently the front out to our
west near St. Louis. The front has been moving a bit slower than
the models had been forecasting an it is expected to hit our area a
little later than previously forecast. As the front approaches,
temperatures will likely rise slightly and we`ll see a return of
snow showers. The front looks to pass through the I-65 corridor
between 11P-12A EST tonight and then through the I-75 corridor by
2-3AM. Colder air will quickly rush in behind the front and
temperatures will fall into the lower 20s by sunrise on Saturday.
The latest HRRR, our local Hi-Res ARW WRF, and RUC data all show
snow shower activity occurring ahead and behind the front. Vertical
sounding profiles actually have a bit of a convective look to them
and I would not be surprised to see more of a snow shower/snow
squall type of activity to develop later tonight. In addition, the
pressure gradient will really tighten up and winds of 15-20 MPH with
gusts up to 30 MPH will be possible. These snow showers will be the
ones that bring the accumulating snow to the region. The snow
combined with temperatures falling into the lower 20s will result in
slick spots developing later tonight. Therefore we will leave the
current winter weather advisory intact...though much of the expected
snowfall and hazardous travel conditions will be delayed until later
tonight and into Saturday morning.
The front will continue to surge eastward on Saturday and
precipitation will end from west to east during the morning hours.
The models are trying to develop a fetch off of Lake Michigan.
However, the models have been often too aggressive with these during
this winter. Nonetheless...some snow shower activity looks to
persist into the morning hours on Saturday and that will likely add
a little more accumulation over in the Bluegrass region. Skies will
likely remain mostly cloudy through much of the day with
temperatures remaining in the 20s. Surface winds will remain
elevated during the day with winds of 10-20 MPH and gusts up to 25
MPH or so. This will keep wind chills down in the single digits at
times on Saturday.
As far as snowfall accumulations...the consensus guidance suggests
around an inch of accumulation for areas generally north of the WK
and BG Parkways. Little accumulation is expected in the far south
and southwest where a 1/2 inch or less will be possible. Highest
accumulations are going to be in the northeast generally east of
U.S. 27 where 1-2 inches of snowfall will be possible by the time
precipitation comes to an end on Saturday.
.Long Term (Saturday Night - Friday)...
Updated at 300 PM EST Feb 10 2012
1040mb high pressure will be over the central Plains Saturday night,
with an equally significant low off the New England coast. The
gradient in between will mean northwesterly winds that will just
start to weaken some as the night progresses. By the day Sunday, the
high will move to around Arkansas, making the strongest winds over
the Bluegrass and weaker across the southwest forecast area.
Temperatures will remain chilly however, with readings only getting
up to around freezing for highs. Wind chills Sunday morning again
look to be in the single digits for most of the area.
The next weather system to impact the region still looks to be
Monday night. Multiple waves within a strengthening southwesterly
flow will allow for precip all along the MS river valley Monday
afternoon and expect this moisture to advect east for the night.
Given forecast temperatures, expect at least a wintry mix for the
night, if not all snow for the north. By midnight, most of the
region should be into light to moderate snow. We could have another
advisory level event over southern Indiana with still some potential
over norther central Kentucky, but it is too early to be that
specific.
The difference with this system, compared to tonight`s snows, will
be that it looks to be followed by some warming for midweek. Models
are still not handling the longer term that well, so do not have
high confidence at this point. The 12Z GFS had a vortmax cross the
region Wednesday that was not in the previous forecast. the 00Z
ECMWF and now the 12Z have hinted at this as well, but there is not
much moisture associated with the impulse. Conversely, the system
that was expected for Thursday has now backed off as well in the 12Z
GFS, but the new ECMWF continues with a large storm system moving
into the midwest. Given such run-to-run inconsistency, will keep in
some precip chances each day, though with lower pops. Also, have
leaned more towards the precip type as rain, with highs into the 50s
Wednesday through Friday.
&&
.Aviation (18Z TAF Issuance)...
Updated at 1231 PM EST Feb 10 2012
Precipitation shield continue to develop over southern Indiana and
Kentucky early this afternoon. Majority of the early precipitation
will likely affect KSDF and KLEX. Cigs and visibilities will likely
jump around as mesoscale bands of light to moderate snow push
through the terminals. For now...we plan on MVFR cigs/vsbys as
prevailing with some tempo drops in visibility to IFR as the bands
affect the terminals. More widespread snow is forecast to develop
later this afternoon with much of the activity likely taking place
after 10/21Z. Further south down at KBWG...a slightly warmer
atmosphere in place will likely result in precipitation being in the
form of a rain/snow mix early this afternoon transitioning over to
all snow by 10/23Z or so. Cigs and vsbys should remain primarily
VFR at BWG this afternoon but drop to MVFR around 10/23 to 11/00Z.
Surface winds will remain out of the southwest this afternoon with
speeds of 4-7 knots. Winds are expected to shift to the northwest
tonight...probably around 11/05-06Z as a strong cold front moves
through. The pressure gradient will also increase late tonight
resulting in winds picking up quite a bit. Northwest winds of
14-18kts are expected and gusts to 28kts will be possible late
tonight through Saturday morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
INZ076>078-083-084-089>092.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR INZ079.
KY...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
KYZ023>030-053>057-061>067-070>078-081-082.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR KYZ031>043-
045>049.
$$
Short Term.......MJ
Long Term........RJS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1257 PM EST FRI FEB 10 2012
.SYNOPSIS...
LOW PRESSURE AND AN ARCTIC COLD FRONT WILL BRING SNOW TONIGHT AND
SATURDAY, FOLLOWED BY COLD TEMPERATURES AND SCATTERED SNOW SHOWERS INTO
SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
HAVE ISSUED WINTER STORM WARNING FOR THE HIGHER MOUNTAINS AND
WINTER WEATHER ADVISORIES FOR THE REST OF THE UPPER OHIO VALLEY
STARTING TONIGHT.
HAVE TWEAKED FORECAST FOR THIS AFTERNOON BASED ON RECENT SURFACE
DATA AND HRRR MODEL OUTPUT. CONTINUE TO EXPECT FIRST SNOW TO BEGIN
LATE AFTERNOON, MAINLY SOUTH OF I-70.
PER RECENT NAM, GFS AND CONSENSUS OF OTHER SREF MODEL OUTPUT,
EXPECT TWO EPISODES OF SNOWFALL. THE FIRST SNOW EPISODE, WILL BE
ASSOCIATED WITH A LOW PRESSURE CENTER PASSING EASTWARD THROUGH THE
CENTRAL APPALACHIAN MOUNTAINS, AND SO SHOULD MAINLY AFFECT
LOCATIONS SOUTH OF PITTSBURGH THIS EVENING. MOST LOCATIONS WILL
GET UP TO AN INCH. HOWEVER, THIS CAN BE ENOUGH TO CAUSE UNTREATED
PAVEMENTS TO BECOME SNOW COVERED AND SLIPPERY, WHICH CAN HAVE AN
IMPACT ON FRIDAY EVENING TRAVELERS.
THE SECOND SNOW EPISODE WILL BE ASSOCIATED WITH A LOW PRESSURE
SYSTEM THAT WILL MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY
LATE TONIGHT AND SATURDAY. THIS SYSTEM WILL DRIVE A STRONG COLD
FRONT THROUGH THE AREA SATURDAY. THE LIFT AND INSTABILITY
ASSOCIATED WITH THE SYSTEM, SHOULD ADD 2-3 INCHES OF SNOW
ACCUMULATION DAYTIME SATURDAY. WINDS CAN GUST OVER 30 MPH, AND SO
CAUSE BLOWING SNOW.
FORECASTED TEMPERATURES USING GFS LAMP AND NAM AND GFS MOS, WHICH
SHOWED TEMPERATURES SATURDAY CAN BE STEADY IN THE MORNING AND
SLOWLY FALLING IN THE AFTERNOON.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
PER RECENT NAM AND GFS MODEL OUTPUT, EXPECT POST FRONTAL,
NORTHWEST-FLOW LAKE-ENHANCED, SNOW SHOWERS TO AFFECT LOCATIONS
EAST OF I-77 SATURDAY NIGHT. NAM MODEL PROFILES SHOW A SUBSIDENCE
INVERSION CAPPING THE INSTABILITY AT 5 KFT AGL SUNDAY, SO SNOWFALL
SHOULD BE LESS DAYTIME SUNDAY, AND END SUNDAY NIGHT. DECIDED TO GO
WITH 7 AM SUNDAY AS CUTOFF FOR WINTER WEATHER HEADLINES.
FORECASTED TEMPERATURES TO BE NEARLY 10 DEGREES COLDER THAN
NORMAL INTO MONDAY MORNING. HIGHS MONDAY AFTERNOON MAY MODERATE TO
WITHIN 5 DEGREES OF NORMAL AS COLD TEMPERATURES WILL HAVE EXITED
WITH INCOMING HIGH PRESSURE.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AN UNSETTLED PATTERN WILL PERSIST THROUGH THE WEEK. LOW PRESSURE
WILL MOVE ACROSS THE EASTERN UNITED STATES MONDAY NIGHT INTO
TUESDAY. HIGH PRESSURE SHOULD ALLOW FOR A BRIEF DRY PERIOD ON
WEDNESDAY BEFORE ANOTHER LOW ARRIVES ON THURSDAY. TEMPERATURES
SHOULD BE NEAR CLIMATOLOGY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
LIGHT SNOW AHEAD OF A COLD FRONT WILL PUSH INTO THE TERMINALS SOUTH OF
KFKL/KDUJ EARLY THIS EVENING, THEN REACH KFKL/KDUJ AFTER 00Z.
PREVAILING MVFR VISIBILITY AND CEILING RESTRICTIONS WITH TEMPO
GROUPS FOR IFR VISIBILITIES ARE FORECAST WITH SNOW THIS EVENING.
PREVAILING VISIBILITIES WITH SNOW WILL LOWER TO IFR OVERNIGHT WITH
CEILINGS PREVAILING AT IFR BY DAWN ON SATURDAY. WINDS WILL BE
SOUTHWESTERLY AROUND 10KTS OVERNIGHT.
THE COLD FRONT WILL REACH THE TERMINALS BETWEEN DAWN AND THE
MID-MORNING HOURS. ALONG AND JUST AHEAD OF THE FRONT, A BURST OF
MORE MODERATE SNOW CAN BE EXPECTED WITH IFR RESTRICTIONS FORECAST
AND LOWER CONDITIONS POSSIBLE. AS THE FRONT PUSHES EAST OF THE AREA,
WINDS WILL SHIFT TO NORTHWESTERLY, INCREASING TO 15KTS WITH GUSTS UP
TO 25-30KTS. SCATTERED SNOW SHOWERS WITH IFR RESTRICTIONS CAN BE
EXPECTED FOR THE REMAINDER OF SATURDAY.
OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY...
A COLD NORTHWESTERLY FLOW WILL ALLOW FOR SCATTERED SNOW SHOWERS WITH
IFR RESTRICTIONS TO CONTINUE SATURDAY NIGHT AND MOSTLY TAPER OFF BY
SUNDAY MORNING. A FEW LINGERING SNOW SHOWERS WITH VISIBILITY
RESTRICTIONS WILL BE POSSIBLE ON SUNDAY. IFR CEILING RESTRICTIONS
WILL PREVAIL EARLY SUNDAY AND LIFT TO MVFR LATE IN THE DAY. HIGH
PRESSURE WILL THEN BUILD IN ON MONDAY WITH VFR CONDITIONS RETURNING
BRIEFLY.
THE NEXT DISTURBANCE WILL MOVE ACROSS THE TERMINALS MONDAY NIGHT
INTO TUESDAY WITH THE CHANCE OF SNOW ALONG WITH RESTRICTIONS. HIGH
PRESSURE WILL THEN BUILD IN FOR WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY
FOR MDZ001.
OH...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST
SATURDAY FOR OHZ039-048-057-058-068.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR OHZ040-041-049-050-059-069.
PA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
SUNDAY FOR PAZ007>009-013>016-022-023.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR PAZ020-021-029-031-073-075.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY
FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR WVZ001>004-012-021-022.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY
FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
425 PM EST FRI FEB 10 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED CENTER OF THE POLAR VORTEX
EAST OF HUDSON BAY WITH A MID/UPPER LEVEL TROUGH AIX TO THE
SOUTHWEST THROUGH ERN LAKE SUPERIOR INTO CTNRL WI. AT THE SFC...A
1046 MB ARCTIC HIGH WAS LOCATED OVER SASK WITH A RIDGE EXTENDING
INTO NRN ONTARIO AND THROUGH THE PLAINS. NNW WINDS IN THE VERY COLD
AIRMASS SUPPORTED LES FOR LOCATIONS FAVORED BY NRLY WINDS.
HOWEVER...LES WAS DIMINISHING AND BANDS WERE SHIFTING WITH THE ACYC
FLOW...BACKING WINDS AND VERY DRY AIR WELL MIXED LOW LEVEL AIR
UPSTREAM WITH SFC DEWPOINTS TO NEAR -20F.
TONIGHT...WITH 850MB TEMPS AROUND -20C...LES WILL BE ONGOING IN
AREAS FAVORED BY NW WINDS. THE DRY AIR AND LOW INVERSION AOB 3KFT
WILL KEEP LES LIGHT INITIALLY. HOWEVER...WITH THE DENDRITIC SNOW
GROWTH TEMP ZONE (DGZ) FIRMLY IN THE CONVECTIVE LAYER...SHOULD STILL
BE ABLE TO GET A FEW INCHES OF FLUFFY SNOW MAINLY OVER THE NE FCST
AREA WHERE ENOUGH MOISTENING CAN OCCUR DESPITE THE DRY AIR.
WINDS OVER FAR SW UPPER MI MAY BACK SUFFICIENTLY TO CUT OVERWATER
TRAJECTORIES ENOUGH TO ALLOW FOR SOME CLEARING. EXPECT TEMPS THERE
TO FALL INTO THE SINGLE DIGITS BLO ZERO. ELSEWHERE...TEMPS ARE
EXPECTED TO REMAIN IN THE SINGLE DIGITS AND LOWER TEENS AS SFC-925MB
WINDS GENERALLY MAINTAIN SOME MODIFICATION OFF OF LAKE SUPERIOR.
SATURDAY...EXPECT LES INTENSITY TO INCREASE BY SAT AFTERNOON AS
850-700 MB MOISTURE INCREASES IN A DEVELOPING WAA PATTERN. WITH
850MB TEMPS MODERATING THROUGH THE DAY THE DGZ WILL CLIMB...BECOMING
MORE FAVORABLY POSITIONED IN THE CONVECTIVE LAYER/UPWARD MOTION
REGION. LONGER FETCH AND LONGER DURATION OF MORE FAVORABLE LES
PARAMETERS SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST
AREA...WHERE AMOUNTS IN THE 2 TO 4 INCH RANGE ARE EXPECTED.
OVER WRN LAKE SUPERIOR...FLOW IS MORE WESTERLY AND ENHANCED
CONVERGENCE COULD DEVELOP BTWN THE PORCUPINE MTNS AND HOUGHTON. THIS
AREA OVER THE WRN CWA COULD ALSO SEE INCREASE IN LES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
CURRENT PUSH OF ARCTIC AIR INTO THE UPPER LAKES WILL BE SHORT LIVED
AS POLAR VORTEX E OF HUDSON BAY RETREATS/REFORMS BACK TOWARD THE
POLE NEXT WEEK. THE RETREAT OF THE NRN STREAM AND A DISTINCT SPLIT
FLOW REGIME NEXT WEEK WILL BRING A RETURN OF THIS WINTERS PREVAILING
THEME OF ABOVE NORMAL TEMPS. WHETHER OR NOT THIS SPLIT FLOW LEADS TO
ANY SRN STREAM SYSTEMS REACHING THE UPPER GREAT LAKES REMAINS TO BE
SEEN. AT THIS POINT...IT STILL APPEARS THAT THE OVERALL DRY PATTERN
WILL PERSIST NEXT WEEK THOUGH THERE ARE MUCH INCREASED UNCERTAINTIES
IN POSSIBLE STREAM INTERACTIONS THAT MAY LEAD TO SOME STORMINESS IN
THE GREAT LAKES LATE IN THE WEEK.
BEGINNING SAT NIGHT...TROF ASSOCIATED WITH POLAR VORTEX E OF HUDSON
BAY WILL BEGIN SHIFTING E...RESULTING IN THE BEGINNINGS OF A WAA
REGIME WHICH WILL CONTINUE THRU SUN. LES WILL BE ONGOING SAT EVENING
OVER THE E AT LOCATIONS FAVORED BY A WNW/NW WIND OFF LAKE SUPERIOR.
HOWEVER...INVERSION QUICKLY SETTLES DOWN TO 4KFT OR LWR LATE EVENING
AND OVERNIGHT. ALSO...WAA BEGINS TO SHIFT DENDRITIC SNOW GROWTH TEMP
ZONE (DGZ) UP ABOVE BEST UPWARD MOTION. IN GENERAL...MIGHT SEE
ANOTHER 1-2 MAYBE 3 INCHES OF SNOW OVER THE NE FCST AREA SAT NIGHT.
OUT W...INVERSION WILL ALREADY BE SETTLING TO 3KFT OR LWR EARLY IN
THE EVENING WITH DGZ ABOVE THE INVERSION. GIVEN THE LOW INVERSION
AND MODERATING AIRMASS...THERE MAY NOT BE MUCH LEFT OTHER THAN
FLURRIES SAT EVENING WITH GRADUAL CLEARING THEN FOLLOWING DURING THE
NIGHT FROM THE W. FROM AN ISENTROPIC STANDPOINT...CONDENSATION PRES
DEFICITS ARE QUITE HIGH SAT NIGHT IN DEVELOPING WAA REGIME...SO
THERE SHOULDN`T BE MUCH IN THE WAY OF WAA CLOUDINESS. ALTHOUGH SKIES
WILL BE CLEARING FROM THE W...MAY NOT BE ABLE TO DECOUPLE COMPLETELY
AS A STRONG PRESSURE GRADIENT STILL EXISTS BETWEEN A 1040MB HIGH
SINKING INTO THE CENTRAL PLAINS AND A 1008MB TROUGH OVER WESTERN
HUDSON BAY/FAR NRN ONTARIO. MINS SHOULD END UP NEAR ZERO IN THE
TRADITIONAL COLD SPOTS OVER THE INTERIOR W HALF...RANGING UP TO THE
TEENS E NEAR LAKE SUPERIOR.
LINGERING LIGHT LES OVER THE NE FCST AREA WILL END SUN AS INVERSION
CONTINUES TO LWR AND MORE IMPORTANTLY TEMPS AT INVERSION BASE RISE
ABOVE -10C. AWAY FROM DIMINISHING LIGHT LES E...SUN SHOULD TURN OUT
TO BE A MAINLY SUNNY DAY UNDER A DEEP DRY AIR MASS. DRY AIR MASS AND
SUNSHINE WORKING ON THE LWR ALBEDO FORESTED LANDSCAPE OF UPPER MI
WILL ASSIST THE WARM UP...BUT STRONG INVERSION WILL HOLD BACK THE
WARMING POTENTIAL OVER WHAT IT COULD BE. FCST SOUNDINGS SUGGEST
MIXING TO 900MB...BUT THAT MIGHT BE A LITTLE OPTIMISTIC. MID/UPPER
20S SHOULD BE THE RULE.
POLAR VORTEX WILL BE RETREATING MON WITH UPSTREAM SPLIT FLOW
ADVANCING INTO THE CNTRL CONUS. IN THE SPLIT...MODEL GUIDANCE
CONTINUES TO INDICATE A SRN STREAM SHORTWAVE MOVING INTO THE MID
MISSISSIPPI VALLEY LATE MON. THERE HASN`T BEEN MUCH MODEL SPREAD
WITH THIS SYSTEM IN RECENT RUNS...AND LATEST ROUND OF GUIDANCE
MAINTAINS THE IDEA THAT THE BULK OF ASSOCIATED PCPN WILL PASS S OF
UPPER MI. SEE NO REASON TO STRAY FROM THAT SCENARIO RIGHT NOW.
SO...CLEAR SKIES SUN NIGHT WILL GIVE WAY TO A SLOW INCREASE IN
HIGH/MID CLOUDS FROM THE SW MON. MAINTAINED SLIGHT CHC POPS ACROSS
THE FAR S/SE MON NIGHT AS THE NRN FRINGE OF PCPN MAY BRUSH THAT
AREA.
TUE THRU FRI...UNDER SPLIT FLOW WITH MORE PROGRESSIVE NRN STREAM...
ARCTIC AIR WILL BE BOTTLED UP WELL TO THE N DURING THE MIDDLE AND
END OF NEXT WEEK. BENIGN/DRY WEATHER SHOULD CONTINUE TUE/WED. EVEN
LES WON`T BE A CONCERN WITH CONSENSUS 850MB TEMPS WARMER THAN -8C.
HEADING INTO THU/FRI...SOME RECENT GFS RUNS HAVE SUGGESTED POSSIBLE
STREAM INTERACTIONS SOMEWHERE FROM THE MISSISSIPPI VALLEY EASTWARD
THAT COULD LEAD TO A STORM SYSTEM IN THE GREAT LAKES AREA. TODAYS
12Z ECMWF RUN IS NOW BEGINNING TO SUGGEST THAT AS WELL. AS ALWAYS...
THERE IS LOW CONFIDENCE IN STREAM PHASING...AND IT GOES WITHOUT
SAYING THAT THERE IS TREMENDOUS UNCERTAINTY IN ANY TYPE OF
INTERACTION THAT FAR OUT IN A MODEL RUN. WILL BE SOMETHING TO
MONITOR IN THE COMING DAYS...BUT FOR NOW...FAVORED THE MORE
DISTINCT...SEPARATED FLOW REPRESENTED BY PREVIOUS ECMWF RUNS. AS A
RESULT...MAINTAINED A DRY FCST FOR THU/FRI THOUGH THERE COULD BE A
LITTLE -SN AT SOME POINT. AIR MASS REMAINS WARM ENOUGH TO PRECLUDE
ANY MENTION OF LES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1224 PM EST FRI FEB 10 2012
EXPECT ALL SITES TO IMPROVE THIS AFTERNOON AS WINDS BACK TO THE NW
AND VERY DRY AIR UPSTREAM FROM LAKE SUPERIOR LIMITS ACTIVITY. LES IS
EXPECTED TO REDEVELOP AT CMX AND IWD OVERNIGHT AS MOISTURE INCREASES
AGAIN WITH NW FLOW. HOWEVER...MAINLY MVFR CONDITIONS WILL PREVAIL
WITH ONLY BRIEF PERIODS OF IFR POSSIBLE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EST FRI FEB 10 2012
NNW WINDS TO 30KT WILL PERSIST WITH AMPLE INSTABILITY IN THE ARCTIC
AIRMASS MOVING OVER THE REGION. NW WINDS APPROACHING GALES TO 35 KT
ARE ALSO POSSIBLE SAT AFTERNOON INTO SAT EVENING OVER ERN LAKE
SUPERIOR. EXPECT HEAVY FREEZING SPRAY ACROSS THE ENTIRE LAKE TONIGHT
THROUGH SAT NIGHT WITH THE STRONG WINDS AND WAVE ACTION. LOOK FOR
HEAVY FREEZING SPRAY TO END ON SUNDAY AS THE AIRMASS WARMS AND WINDS
GRADUALLY DIMINISH. CONDITIONS WILL QUIET DOWN FOR THE EARLY PART OF
THE WORK WEEK AS A HIGH PRES RIDGE MOVES OVER THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LMZ221-250.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1220 PM EST FRI FEB 10 2012
LATEST UPDATE...SHORT TERM AND MARINE...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(1220 PM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WENT AHEAD AND STARTED THE ADVISORY A LITTLE EARLIER THAN INITIALLY
INDICATED SINCE SNOW HAS ALREADY BEEN UNDERWAY FOR A FEW HOURS.
HOWEVER THE MAIN HAZARD... THE COLD AIR... IS A TAD DELAYED DUE A
WAVE ON THE FRONT. AT NOON THE FRONT WAS FROM JUST NORTH OF MUSKEGON
TO HOUGHTON LAKE... AND IS NOT PROJECTED INTO GRR UNTIL 4-5 PM. IT
MAY NOW HOLD OFF AT AZO/BTL/LAN UNTIL 7 PM.. AND PERHAPS 9 PM AT
JXN. THIS IS GOOD NEWS SINCE LOCATIONS SOUTH AND EAST OF GRR MAY BE
ABLE TO GET THROUGH THE BULK OF THE EVENING COMMUTE BEFORE THE
REALLY COLD ARRIVES AND ICES UP THE ROADS. THAT WOULD CERTAINLY HELP
LIMIT THE IMPACTS. ONE THING TO NOTE HOWEVER IS THAT SOME OF THE
SHORT TERM GUIDANCE IS LAGGING BEHIND AT THE INITIALIZATION WITH THE
ARCTIC AIR.. SO THE ARRIVAL OF THE COLD AIR COULD STILL BE EARLIER
THAN INDICATED ABOVE.
PREVIOUS DISCUSSION...
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMINISH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(1200 PM EST FRI FEB 10 2012)
MVFR TO IFR CONDITIONS AT ALL THE TERMINALS MAY TEMPORARILY DIP INTO
THE LIFR CATEGORY LATER THIS AFTN AND EARLY EVE AS SNOW INCREASES
NEAR THE ARCTIC FRONT. WINDS WILL INCREASE SIGNIFICANTLY AND VEER TO
THE NORTH RIGHT AFTER FROPA MID TO LATE AFTN INTO THE EVE AT ALL THE
TERMINALS. GUSTS WILL REACH 25 KTS AT ALL TERMINALS THROUGH THE
EVENING. HIGHER GUSTS TO 30 KTS ARE POSSIBLE PARTICULARLY AT KMKG.
SNOW SHOWERS WILL GRADUALLY END AT MOST OF THE TERMINALS OVERNIGHT
WITH MAINLY MVFR CONDITIONS LATE TONIGHT INTO SATURDAY DUE TO
LINGERING LOW CLOUDS. HOWEVER LAKE EFFECT SNOW SHOWERS WILL DEVELOP
OVERNIGHT AND IMPACT KMKG RESULTING IN MAINLY IFR CONDITIONS THERE.
AS LOW LEVEL WINDS BACK FROM THE NORTH TO THE NW SATURDAY MORNING I
EXPECT THAT THE LAKE EFFECT SNOW BAND WILL BEGIN TO PROPAGATE INLAND
AND POTENTIALLY REACH KGRR AND KAZO AND POINTS ALONG THE US-131
CORRIDOR TOWARD MIDDAY SATURDAY.
&&
.MARINE...(1220 PM EST FRI FEB 10 2012)
BIG SABLE POINT WAS ALREADY GUSTING TO GALE FORCE BEHIND THE FRONT
AT 11 AM... SO UPGRADED EARLIER TO A GALE WARNING THROUGH SATURDAY
MORNING.
AS TEMPS FALL BELOW FREEZING LATER THIS AFTERNOON AND TONIGHT...THE
GUSTY WINDS MAY RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THROUGH 10 PM FOR ALL BUT THE NORTHERN
TWO ROWS OF COUNTIES.
LM...GALE WARNING IN EFFECT THROUGH SATURDAY MORNING.
SMALL CRAFT ADVISORY SATURDAY MORNING THROUGH SUNDAY AFTERNOON.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93/MEADE
LONG TERM: MJS
AVIATION: LAURENS
MARINE: MEADE
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1200 PM EST FRI FEB 10 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(346 AM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMINISH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(1200 PM EST FRI FEB 10 2012)
MVFR TO IFR CONDITIONS AT ALL THE TERMINALS MAY TEMPORARILY DIP INTO
THE LIFR CATEGORY LATER THIS AFTN AND EARLY EVE AS SNOW INCREASES
NEAR THE ARCTIC FRONT. WINDS WILL INCREASE SIGNIFICANTLY AND VEER TO
THE NORTH RIGHT AFTER FROPA MID TO LATE AFTN INTO THE EVE AT ALL THE
TERMINALS. GUSTS WILL REACH 25 KTS AT ALL TERMINALS THROUGH THE
EVENING. HIGHER GUSTS TO 30 KTS ARE POSSIBLE PARTICULARLY AT KMKG.
SNOW SHOWERS WILL GRADUALLY END AT MOST OF THE TERMINALS OVERNIGHT
WITH MAINLY MVFR CONDITIONS LATE TONIGHT INTO SATURDAY DUE TO
LINGERING LOW CLOUDS. HOWEVER LAKE EFFECT SNOW SHOWERS WILL DEVELOP
OVERNIGHT AND IMPACT KMKG RESULTING IN MAINLY IFR CONDITIONS THERE.
AS LOW LEVEL WINDS BACK FROM THE NORTH TO THE NW SATURDAY MORNING I
EXPECT THAT THE LAKE EFFECT SNOW BAND WILL BEGIN TO PROPOGATE INLAND
AND POTENTIALLY REACH KGRR AND KAZO AND POINTS ALONG THE US-131
CORRIDOR TOWARD MIDDAY SATURDAY.
&&
.MARINE...(346 AM EST FRI FEB 10 2012)
WE/LL SEE AN ABRUPT WIND SHIFT TODAY AS A STRONG COLD FRONT MOVES
THROUGH. WINDS WILL GUST FROM THE NORTH BEHIND THE FRONT TO JUST
UNDER GALE FORCE AND THEN DIMINISH OVERNIGHT. AS TEMPS FALL BELOW
FREEZING LATER THIS AFTERNOON AND TONIGHT...THE GUSTY WINDS MAY
RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THIS AFTERNOON AND EVENING FOR ALL BUT
THE NORTHERN TWO ROWS OF COUNTIES.
LM...GALE WARNING IN EFFECT THROUGH SATURDAY MORNING.
SMALL CRAFT ADVISORY SATURDAY MORNING THROUGH SUNDAY AFTERNOON.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93
LONG TERM: MJS
AVIATION: LAURENS
MARINE: 93
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS BILLINGS MT
249 PM MST FRI FEB 10 2012
.SHORT TERM...VALID FOR SAT AND SUN...
SNOW CONTINUES THIS AFTERNOON IN OUR WEST NEAR LIVINGSTON AND BIG
TIMBER AND ALONG THE BEARTOOTH ABSAROKA FOOTHILLS. IMPRESSIVE DRY
SURGE HAS CLEARED OUT SKIES EAST OF A HYSHAM TO BROADUS LINE...AND
IN THIS AREA SFC DEWPTS ARE IN THE SINGLE DIGITS BELOW ZERO. MOIST
ISENTROPIC ASCENT WILL CONTINUE TO BRING SNOWFALL TO OUR FAR WEST
TONIGHT...WITH ENHANCEMENT IN UPSLOPE AREAS ALONG THE BEARTOOTH
FOOTHILLS. THIS ASCENT ALONG WITH NORTH WINDS SHOULD ALSO BRING
ADDITIONAL ACCUMULATION TO THE PARADISE VALLEY THROUGH TONIGHT.
HAVE OPTED TO ADD THE RED LODGE FOOTHILLS TO THE ADVISORY...LESS
FOR THE CITY OF RED LODGE ITSELF WHICH IS A BIT SHELTERED IN THIS
EVENT AND MORE FOR THE WESTERN PART OF THIS ZONE NEAR ROSCOE AND
LUTHER...WHERE WEB CAMERAS AND RADAR SHOW PCPN HAS BEEN A BIT
HEAVIER. OVERALL TOTALS OF 3 TO 6 INCHES SHOULD SUFFICE FOR ALL OF
THESE AREAS THROUGH 6AM SATURDAY.
AS FOR THE CITY OF BILLINGS...WE ARE CAUGHT BETWEEN THE MOIST
ASCENT TO OUR WEST AND DRY AIR TO OUR EAST. WITH LOW LEVEL UPSLOPE
AND DENDRITIC LAYER IN PLACE WE WILL LIKELY SEE PERIODS OF VERY
LIGHT SNOW OR FLURRIES TONIGHT...BUT WITH LITTLE IF ANY ADDITIONAL
ACCUMULATION AS THE MOISTURE WILL BE SHALLOW. WE MAY EVEN DRY OUT
COMPLETELY LATE TONIGHT AS THE LATEST RUC IS SUGGESTING. WE MISSED
OUT ON A MORE SIGNIFICANT SNOW EVENT IN THE CITY OF BILLINGS BY 50
TO 100 MILES.
ONSET OF WEAK MID LEVEL WARM ADVECTION COMBINED WITH THE LOW LEVEL
UPSLOPE AND DENDRITIC LAYER WILL ALLOW FOR LIGHT SNOW OR FLURRIES
TO CONTINUE ACROSS OUR WEST HALF TOMORROW AND TOMORROW NIGHT. THIS
INCLUDES THE CITY OF BILLINGS WHICH SHOULD SEE MOISTURE DEEPEN A
BIT OVER TIME ON SATURDAY. ACCUMULATIONS WILL BE MEAGER AT LESS
THAN AN INCH DURING THIS TIME PERIOD.
WEAK TROFFING AND CYCLONIC FLOW WILL KEEP THE THREAT OF FLURRIES
GOING ON SUNDAY...BUT WITH A TRANSITION TO WEAK LOW LEVEL
DOWNSLOPE FLOW AND WARMER TEMPS.
EXPECT THE COLDEST NIGHT IN AWHILE TONIGHT WITH SINGLE DIGITS AT
BILLINGS AND BELOW ZERO IN THE DRY AIR TO OUR EAST. COLD AIRMASS
WILL REMAIN IN PLACE PER LEE SIDE SFC RIDGING AND EAST WINDS ON
SATURDAY...WITH HIGHS MOSTLY IN THE 20S...THOUGH WITHOUT SNOW
COVER OUR EAST WILL SEE A FAIR DIURNAL RISE DURING THE DAY.
AIRMASS WILL MODERATE FURTHER ON SUNDAY THOUGH DOWNSLOPE FLOW WILL
BE FAIRLY WEAK SO WARM UP WILL NOT BE DRAMATIC...ESPECIALLY WITH
SOME SNOW COVER TO DEAL WITH IN OUR WEST. SHOULD SEE HIGHS INTO
THE 30S ON SUNDAY...IE CLOSER TO MID FEBRUARY NORMALS.
JKL
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
RELATIVELY MINOR CHANGES ONCE AGAIN TO THE EXTENDED PERIOD...AS
MODELS CONTINUE TO DIVERGE AFTER TUESDAY.
RIDGING ALOFT SHOULD ALLOW TEMPS TO RISE BACK TO AROUND 40 IN MOST
AREAS ON MONDAY...WITH RELATIVELY LIGHT SNOW COVER REMAINING.
WOULD NOT EXPECT TO SEE MUCH IN THE AWAY OF POPS OUTSIDE THE
MOUNTAINS...BUT INHERITED POPS INCREASING IN THE MOUNTAINS THROUGH
MONDAY LOOKS GOOD WITH INCREASING MOISTURE AVAILABILITY.
THE TROF PROGGED FOR TUESDAY STILL LOOKS TO BE ON TRACK...BUT ALSO
CONTINUES TO BE UNIMPRESSIVE WITH MINIMAL DYNAMIC SUPPORT. CANNOT
RULE OUT SLIGHT POPS INTO PLAINS TUESDAY AFTERNOON/EVENING. LOOKS
LIKE CLOUD COVER AND PUSH OF COOL AIR SHOULD BE ENOUGH TO LIMIT
HIGH TEMPS TO MID 30S IN MOST AREAS.
PATTERN GENERALLY CONTINUES WITH RIDGING AND MOISTURE INFLUX FOR
WEDNESDAY...BUT AT THIS POINT MODELS ARE DIVERGING AGAIN. GFS
DROPS ANOTHER TROF THROUGH THE REGION...IMPACTING MAINLY THE
WESTERN AND CENTRAL ZONES...WHILE EC MAINTAINS NORTHERLY FLOW IN
ADVANCE OF RIDGE. THE MODELS THEN SEEM TO SUPPORT RIDGING THROUGH THE
END OF THE EXTENDED...WITH GFS BRINGING STRONG PACIFIC TROF IN
FOLLOWING THE END OF THE FORECAST PERIOD. HAVE CONTINUED WITH
MAINLY CLIMO TYPE TEMPS THROUGH THIS PERIOD...AS AM SEEING
NOTHING TO POINT SIGNIFICANTLY HIGHER OR LOWER. AAG
&&
.AVIATION...
MVFR FLIGHT CONDITIONS PREVAIL ACROSS SOUTH CENTRAL MONTANA...UNDER
LOW CIGS. LOCALIZED IFR CONDITIONS CONTINUE IN HEAVIER SNOW
SHOWERS DUE TO REDUCED VIS...ESPECIALLY WEST AND SOUTH OF
KBIL...INCLUDING KLVM AND K6SO. AREAS FURTHER EAST AND
NORTHEAST...INCLUDING KMLS AND KBHK...WILL REMAIN CLEAR. SNOW IS
EXPECTED TO CONTINUE THROUGH THE NIGHT AND INTO SATURDAY...BUT
WITH LITTLE ACCUMULATION OTHER THAN IN HEAVIER BAND WEST OF KBIL.
MOUNTAINS WILL BE OBSCURED THROUGH THE REMAINDER OF THE EVENING
AND OVERNIGHT. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 006/023 014/036 021/042 023/036 023/038 023/038 023/042
86/S 31/M 11/B 12/J 21/B 11/B 22/J
LVM 013/028 018/038 022/040 018/035 020/036 017/036 018/040
+7/S 41/M 11/B 12/J 21/B 11/B 22/J
HDN 006/027 011/035 020/042 021/037 021/039 020/039 021/043
43/S 21/M 11/B 12/J 21/B 11/B 22/J
MLS 905/027 006/033 019/041 022/036 021/038 021/038 022/042
00/U 00/B 11/B 12/J 21/B 11/B 11/B
4BQ 903/028 009/032 019/042 022/037 021/038 021/038 021/042
01/U 01/B 11/B 12/J 21/B 10/B 11/B
BHK 909/025 001/030 017/039 019/035 019/035 018/035 017/039
00/U 00/U 01/U 12/J 21/B 10/B 11/B
SHR 009/028 012/036 020/042 018/035 019/036 016/036 017/040
74/S 21/M 11/B 12/J 21/B 11/B 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST SATURDAY FOR
ZONES 34-41-56-64>66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
349 PM EST FRI FEB 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTH THIS EVENING...THEN DROP
ACROSS THE REGION LATE TONIGHT. SCATTERED SNOW SHOWERS THROUGH THIS
EVENING WILL BECOME MORE WIDESPREAD LATE TONIGHT INTO SATURDAY. THIS
WILL BRING IN COLDER TEMPERATURES AND SOME SNOW ACCUMULATION.
ANOTHER COLD FRONT WILL APPROACH FROM THE NORTH...WHICH WILL LIKELY
BRING A ROUND OF LAKE SNOWS LATE SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
OUR WEATHER WILL CONTINUE TO KEY ON THE PROGRESSION OF AN
APPROACHING FRONTAL BOUNDARY. OUTSIDE OF SOME LAKE EFFECT EAST OF
LAKE ONTARIO...EXPECT GENERALLY LIGHT AND PATCHY SNOW ACCUMULATION
AHEAD OF THE FRONT.
THE 12Z MODEL RUNS CONTINUE TO SLOW THE PROGRESSION OF THE COLD
FRONT. THE UPPER LEVEL TROF DRIVING THE FRONT IS FORECAST TO
SHARPEN...WHICH EFFECTIVELY SLOWS THE PROGRESSION OF THE FRONT...AND
ALSO AIDS IN THE DEVELOPMENT OF A WEAK SURFACE LOW ALONG THE
BOUNDARY. THE 12Z NAM/GFS/RGEM ARE ALL SUPPORTING THIS SLOWER
PROGRESSION...WHICH HAS BEEN THE TREND FOR SEVERAL RUNS NOW.
THIS WILL HAVE A FAIRLY SIGNIFICANT IMPACT ON THE FORECAST...SINCE
THE SLOWER PROGRESSION OF THE FRONT WILL PUSH BACK START TIME OF THE
STEADY SNOW UNTIL LATE TONIGHT. ACROSS NORTHWESTERN NEW YORK FROM
BUFFALO-ROCHESTER NORTHWARD...EXPECT THE STEADIEST SNOW FROM 600 AM
THROUGH NOON...SLIGHTLY LATER TO THE SOUTH OF THIS.
GENERALLY ACCEPT THE CONSENSUS QPF FROM THE 12Z NAM12/RGEM...THOUGH
SOME UPSLOPE ENHANCEMENT MAY OCCUR BEYOND MODEL QPF FORECASTS. THERE
SHOULD BE A PERIOD OF SNOW BOTH ALONG THE FRONT...AND BEHIND THE
FRONT DUE TO LAKE ENHANCEMENT AND UPSLOPING.
EXPECT THE MOST SNOW TO FALL ACROSS WESTERN PORTIONS OF THE SOUTHERN
TIER...WHERE THE SURFACE LOW...UPPER LEVEL TROF...AND UPSLOPING
SHOULD ALL COME TOGETHER TO BRING SEVERAL HOURS OF MODERATE SNOWS.
EXPECTING 3 TO 5 INCHES IN THE FAVORABLE UPSLOPE RIDGES...AND BASED
ON THIS WILL ISSUE A WINTER WEATHER ADVISORY FOR
CHAUTAUQUA/CATTARAUGUS COUNTIES. SNOW AMOUNTS WILL BE LESS
ELSEWHERE...THOUGH GENERALLY EXPECT 2 OR 3 INCHES IN BUFFALO
METRO/BOSTON HILLS/NIAGARA FRONTIER. AMOUNTS TO THE EAST SHOULD BE
LESS...FURTHER FROM THE UPPER TROF...WITH GENERALLY 2 INCHES OR LESS
EXPECTED.
THE EAST TO WEST ORIENTATION OF THE FRONT WILL ALLOW IT TO DROP
ACROSS THE NORTH COUNTRY EARLIER...WITH THE FRONT LIKELY TO SLOWLY
DROP ACROSS SHORTLY AFTER MIDNIGHT. WHILE THIS REGION IS FURTHER
REMOVED FROM THE UPPER LOW AND THE DEEPER MOISTURE...THERE WILL BE A
PERIOD FAVORABLE FOR LAKE ENHANCEMENT IMMEDIATELY AHEAD OF THE
FRONT. RADAR TRENDS AND THE HRRR SUPPORT DEVELOPMENT OF FAIRLY
WIDESPREAD LAKE ENHANCED SNOW SHOWERS AHEAD OF THE FRONT...DESPITE
MINIMAL QPF FROM THE NAM/RGEM. HERE...MOST OF THE SNOW SHOULD FALL
LATE AFTERNOON AND THIS EVENING...AHEAD OF THE FRONT...WHERE 1 TO 3
INCHES IS POSSIBLE ON THE TUG HILL AND IN JEFFERSON COUNTY.
THE SLOWER PROGRESSION OF THE FRONT WILL ALSO HAVE A BIG IMPACT ON
TEMPERATURES. WHILE THE FRONT WILL STILL PASS THROUGH THE NORTH
COUNTRY...IT IS QUESTIONABLE IF THE COLD AIR WILL MAKE IT INTO
BUFFALO BY DAYBREAK. THE RESULT IS LOW TEMPERATURES WHICH ARE QUITE
A BIT WARMER ALONG THE I-90 CORRIDOR. THIS SAID...THE FRONT WILL
STILL CROSS...AND TEMPERATURES WILL DROP BEHIND THE FRONT SATURDAY
MORNING. SATURDAY WILL STILL BE A COLD DAY...WITH MID-DAY
TEMPERATURES IN THE UPPER TEENS TO LOWER 20S...EVEN IF THE MORNING
STARTS OFF A BIT WARMER THAN THIS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AN ACTIVE PERIOD SATURDAY NIGHT AND INTO SUNDAY AS LAKE EFFECT SNOW
IS EXPECTED...ENHANCED BY A SOUTHWARD DROPPING ARCTIC FRONT SUNDAY.
SATURDAY NIGHT THE AXIS OF AN UPPER LEVEL TROUGH WILL BE CROSSING
THE REGION...WITH WINDS THROUGH THE BOUNDARY LAYER EXHIBITING TOO
MUCH SHEER...AND LIMITED BOUNDARY LAYER MOISTURE FOR ANY LAKE EFFECT
TO BE ONGOING. SYNOPTIC SNOW WILL BE ENDING ACROSS THE SOUTHERN TIER
EARLY SATURDAY NIGHT WITH LITTLE FURTHER SNOW ACCUMULATION.
TEMPERATURES ALOFT AT 850 HPA WILL BE PLENTY COLD ENOUGH TO SUPPORT
LAKE EFFECT SNOW THOUGH LIFT REMAINS MARGINAL AND MOISTURE IN THE
GOOD SNOW CRYSTAL GROWTH ZONE REMAINS LIMITED TO START.
AS THE NIGHT PROGRESS MOISTURE IN THE LOWER LEVELS INCREASES AND
LAKE INDUCED EQUILIBRIUM LEVELS INCREASE ALONG WITH A DECREASE IN
WIND SHEAR. THIS WILL FAVOR THE FORMATION OF LAKE EFFECT SNOW
BANDS...WITH AN UPSTREAM CONNECTION TO LAKE HURON AND GEORGIAN BAY
LIKELY. THE GREATEST LIFT WILL BE CENTERED OVER LAKE ONTARIO AND
INLAND TOWARDS THE GENESEE VALLEY AND WITH AN UPSTREAM CONNECTION TO
GEORGIAN BAY HERE IS WHERE THE HEAVIEST SNOW BAND IS EXPECTED.
WITH THE UPPER LEVEL WINDS A LITTLE MORE BACKED IN THE LONG WAVE
TROUGH THE FOCUS OF THE LAKE EFFECT SNOW SATURDAY NIGHT IS EXPECTED
TO BE CENTERED MORE FROM SOUTHERN SHORELINE OF LAKE ONTARIO AND
INLAND ACROSS THE NORTHERN GENESEE VALLEY AND TOWARDS THE WESTERN
FINGER LAKES REGION...AND BECOMING LESS LIKELY TOWARDS THE EASTERN
END OF LAKE ONTARIO.
NORTHWEST FLOW ACROSS LAKE ERIE WILL BE PERPENDICULAR...AND LOW
LEVEL LIFT AND CONVERGENCE IS NOT AS GREAT. SNOW OF LAKE ERIE WILL
BE FOCUSED UPON AREAS SOUTH OF BUFFALO...ACROSS SKI COUNTRY AND THE
SOUTHERN TIER.
TOWARDS SATURDAY NIGHT AN ARCTIC FRONT WILL BE DROPPING SOUTHWARD
ACROSS OUR REGION FROM SOUTHERN CANADA. BY 12Z SUNDAY EXPECT THIS
FRONT TO BE PUSHING TOWARDS THE SOUTHERN SHORELINE OF LAKE ONTARIO.
BEHIND THIS FRONT SFC TEMPERATURES WILL DROP INTO THE SINGLE DIGITS
AND LOWER...AND WITH WINDS LIKELY IN THE 5 TO 10 KNOTS RANGE WIND
CHILLS WILL FALL TO -20F OR LOWER SUNDAY MORNING ACROSS PORTIONS OF
THE NORTH COUNTRY. WILL MENTION THESE WIND CHILL TEMPERATURES IN THE
HWO...WITH FURTHER SHIFTS MONITORING FOR ANY WIND CHILL ADVISORIES.
AS THIS ARCTIC FRONT DROPS SOUTHWARD EXPECT THE BAND OF LAKE EFFECT
SNOW OFF LAKE ONTARIO TO BECOME ENHANCED. INCREASING WIND SPEEDS AND
COLD TEMPERATURES WILL CREATE BLUSTERY AND BLOWING SNOW CONDITIONS
EARLY SUNDAY MORNING...AND AS THE FRONT DROPS SOUTHWARD EXPECT THIS
BOUNDARY TO TAKE THE LAKE EFFECT SNOWBAND AND PUSH IT SOUTHWARD WELL
INLAND ACROSS SOUTH OF LAKE ONTARIO. THIS MAY CREATE A SEVERAL HOUR
PERIOD OF REDUCED VISIBILITIES WITHIN THE BLOWING AND FALLING SNOW.
LAKE EFFECT SNOW/SNOW ALONG THE ARCTIC FRONT WILL CONTINUE THROUGH
THE DAY SUNDAY WITH THE FOCUS ALONG THE ARCTIC FRONT. WIND SHEER MAY
DISRUPT THE BANDS THROUGH THE DAY SUNDAY TO HOLD SIGNIFICANT
ACCUMULATIONS FROM OCCURRING AT ANY GIVEN LOCATION. WAA STARTS LATER
IN THE DAY SUNDAY...BUT WITH THE DEEP COLD AIRMASS TEMPERATURES
SUNDAY WILL REMAIN COLD ENOUGH TO SUPPORT LAKE EFFECT
ACTIVITY...WHILE AFTERNOON HIGHS REMAIN BELOW NORMAL.
HIGH PRESSURE FOLLOWING THE ARCTIC FRONT WILL BUILD ACROSS THE NORTH
COUNTRY SUNDAY AND WILL JUST HAVE CHC POPS EARLY SUNDAY ACROSS THE
NORTH COUNTRY...WHILE SOUTHWARD WILL HAVE LIKELY TO CATEGORICAL
POPS.
LAKE EFFECT SNOW WILL DIMINISH SUNDAY NIGHT AND AS THE WINDS
BACK...LIFT NORTHWARD TOWARDS THE EASTERN LAKE ONTARIO REGION
MONDAY. AS THE UPPER LEVEL RIDGE BUILDS ACROSS THE REGION MONDAY
EXPECT SKIES TO CLEAR...WITH TEMPERATURES RISING BACK TO THE
FREEZING MARK...AND NEAR NORMAL.
CLOUDS WILL INCREASE THROUGH THE NIGHT MONDAY NIGHT AS THE NEXT
SYSTEM FROM THE WEST NEARS THE REGION WITH LIGHT SNOW RETURNING LATE
TO WNY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
SEVERAL UPPER LEVEL SHORT WAVES THROUGH A SPLIT FLOW THIS TIME
PERIOD WILL CREATE AN ACTIVE TIME PERIOD FOR THE LONG RANGE...THOUGH
EACH SINGLE SYSTEM AT PRESENT MOMENT DOES NOT APPEAR SIGNIFICANT.
WITH A RETURN TO A MORE ZONAL FLOW THIS PERIOD TEMPERATURES WILL
AVERAGE AROUND NORMAL...WITH ANY GREAT DEPARTURES FROM NORMAL COMING
ON ANY PHASING OF THE NORTHERN AND SOUTHERN SHORTWAVES...THEREBY
AMPLIFYING THE FLOW SOME.
TUESDAY THE GFS/ECMWF/GGEM BRING A WEAK SHORT WAVE EJECTING FROM THE
SOUTHWEST ACROSS THE EASTERN GREAT LAKES. TEMPERATURES ALOFT ON BOTH
THE GFS/ECMWF RANGE FROM -6 TO -8C AND WITH THE 06Z GEFS MEMBERS
SUPPORTING ALL SNOW WILL KEEP THE P-TYPE AS SNOW FOR VALENTINES DAY.
FOR NOW WILL LEAVE AS HIGH CHANCE POPS...AS QPF IS ON THE LIGHT SIDE
AND THE SHORT WAVE IS EXPECTED TO FLATTEN OUT AS IT NEARS THE NORTH
EAST. TEMPERATURES TUESDAY UNDER A CLOUDY SKY WILL NOT STRAY MUCH
FROM NORMAL.
WILL HAVE SNOW TAPERING OFF TUESDAY NIGHT WITH THE FLATTENING
SHORTWAVE PASSING BY.
TIMING AND STRENGTH OF THE NEXT SHORT WAVE...THIS TIME IN THE
NORTHERN BRANCH OF THE JET STREAM REMAINS UNCERTAIN. BOTH THE 12Z
GFS AND 12Z ECMWF HAVE BOTH BEEN HINTING AT A SHORT WAVE
CROSSING...THOUGH TIMING AND STRENGTH HAVE BEEN FLUCTUATING. WILL
CONTINUE WITH LOW CHC POPS FOR WEDNESDAY.
BOTH THE GFS AND ECMWF HAVE A SFC HIGH PRESSURE ACROSS THE REGION
WEDNESDAY NIGHT AND INTO THURSDAY MORNING AND THIS FEATURE WILL
ALLOW FOR DIMINISHING POP CHCS THOUGH WITH LOW LEVEL MOISTURE
REMAINING...AND POSSIBLY TRAPPED BELOW AN INVERSION WILL MAINTAIN
MOSTLY CLOUDY SKY CONDITIONS.
BOTH THE OPERATIONAL RUNS OF THE GFS AND ECMWF BRING ANOTHER
SHORTWAVE ACROSS THE EASTERN GREAT LAKES LATER THURSDAY AND
INTO FRIDAY ALONG WITH AN INCREASE IN MOISTURE. WILL BRING CHC POPS
BACK TO THE REGION LATE THURSDAY TO THE SOUTHERN TIER...AND THROUGH
THE NIGHT THURSDAY AND INTO FRIDAY.
PRECIPITATION TYPE WEDNESDAY THROUGH FRIDAY IS CHALLENGING AS 850S
RISE TO NEAR -4C ON THE GFS WEDNESDAY...THOUGH THE ECMWF MAINTAINS A
DEEPER COOL POOL OVER THE EASTERN GREAT LAKES. WILL HAVE BOTH RAIN
AND SNOW MENTIONED IN THE GRIDS FOR WEDNESDAY...
A MILDER RETURN FLOW BEHIND THE DEPARTING SFC HIGH THURSDAY AND
FRIDAY WILL ALSO ALLOW FOR PRECIPITATION TO COME AS A MIX OF RAIN AND
SNOW FOR LATER THURSDAY AND FRIDAY ACROSS THE REGION.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
FROM 21Z TODAY THROUGH 09Z SATURDAY...EXPECT A MIX OF VFR/MVFR
CONDITIONS IN MARGINAL CIGS AND VSBY IN AREAS OF LIGHT SNOW AND
FLURRIES. ONE AREA TO WATCH IS ART...WHERE A BIT MORE INTENSE LAKE
EFFECT BAND MAY DEVELOP...WITH A PERIOD OF IFR CONDITIONS LIKELY
THIS EVENING.
CONDITIONS WILL LOWER SIGNIFICANTLY AT MOST SITES SATURDAY
MORNING...AS A FRONTAL BOUNDARY DROPS ACROSS THE REGION. THIS
FRONTAL PASSAGE WILL KEY A MORE INTENSE PERIOD OF SNOW...WITH IFR
OR LOWER CONDITIONS LIKELY TOWARD DAYBREAK SATURDAY INTO SATURDAY
MORNING.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...PERIODS OF IFR OR LOWER IN LAKE EFFECT SNOW
SHOWERS.
MONDAY...MAINLY VFR.
TUESDAY AND WEDNESDAY...VFR/MVFR IN CHC OF SNOW.
&&
.MARINE...
WINDS HAVE LARGELY DIMINISHED ACROSS THE WATERS...WITH THE EXCEPTION
OF LAKE ERIE WHERE A SW FLOW SUPPORTS SMALL CRAFT HEADLINES INTO
THIS EVENING. AFTER THIS...THE KEY WILL BE A STRONG COLD
FRONT...WHICH WILL BRING A DECENT NORTHERLY FLOW IN ITS WAKE. FOR
NOW...WILL ISSUE THE SMALL CRAFT ADVISORY FOR THE SOUTH SHORES OF
LAKE ONTARIO. THIS WILL LIKELY HAVE TO BE EXTENDED TO LAKE
ERIE...BUT WILL LET FUTURE SHIFTS DO THIS AS HEADLINES ARE ALREADY
IN PLACE FOR ONGOING CONDITIONS.
WINDS SHOULD DIMINISH SATURDAY NIGHT...BUT ANOTHER FRONTAL BOUNDARY
WILL CAUSE WINDS TO INCREASE AGAIN ON SUNDAY AND SUNDAY NIGHT.
EXPECT SOLID SMALL CRAFT WINDS...WITH THE POSSIBILITY OF GALES
DURING THIS PERIOD. HIGH PRESSURE WILL BUILD TOWARD THE WATERS EARLY
NEXT WEEK.
ONE CONCERN IS THE POTENTIAL FOR FREEZING SPRAY ON SATURDAY NIGHT
INTO SUNDAY...AS TEMPERATURES DROP AND WINDS INCREASE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 4 AM TO 5 PM EST SATURDAY FOR
NYZ019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EST THIS EVENING FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 5 AM EST
SUNDAY FOR LOZ042>044.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...APFFEL
MARINE...APFFEL/RSH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
110 PM EST FRI FEB 10 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM MOVES ACROSS THE MID ATLANTIC AND CAROLINAS
OVERNIGHT...STRENGTHENING OVER THE ATLANTIC SATURDAY. A STRONG COLD
FRONT SWEEPS THROUGH THE REGION IN THE WAKE OF THE LOW SATURDAY.
COLD HIGH PRESSURE BUILDS IN BEHIND THE FRONT FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 1000 AM FRIDAY...
OVERVIEW:
SHORTWAVE ENERGY OVER MISSISSIPPI AND ALABAMA THIS MORNING WILL MOVE
ACROSS THE STATE THIS AFTERNOON AND THIS EVENING. FURTHER
UPSTREAM...A POTENT UPPER LEVEL TROUGH WILL DIG SOUTHEAST INTO THE
UPPER MIDWEST/UPPER GREAT LAKES...PROGRESSING INTO THE OHIO VALLEY
TONIGHT AND APPROACHING THE MID-ATLANTIC BY 12Z SAT. LOW-LEVEL FLOW
WILL BACK TO THE SOUTHWEST TODAY IN ADVANCE OF A SFC-850 MB TROUGH
APPROACHING THE AREA FROM THE WEST. A LOW-LEVEL TROUGH WILL
PROGRESS THROUGH THE CAROLINAS TONIGHT BEFORE MOVING OFFSHORE BY 12Z
SAT MORNING.
PRECIPITATION AND TEMPERATURES THIS AFTERNOON:
CLOUDS HAVE ADVECTED INTO THE AREA QUICKLY THIS MORNING...AND WILL
BE SPREADING TOWARD KIXA QUICKLY AS WELL TOWARD THE NOON HOUR.
CONSIDERABLE CLOUDINESS TO THE SOUTHWEST WILL RESULT IN A MOSTLY
CLOUDY TO CLOUDY SKY ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON.
MUCH OF THE GUIDANCE SUPPORTS QPF IN PARTS OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN THIS AFTERNOON...WHILE THE RUC IS DRIEST.
TOOK A CLOSE LOOK AT THE RUC FOR ITS EVIDENCE OF DRIER CONDITIONS...
AND EVEN THAT MODEL SHARPENS THE INVERTED SURFACE TROUGH NEAR THE
COAST LATE THIS AFTERNOON AS THE LEFT EXIT REGION OF A 125KT 300MB
JET SHIFTS SOUTH. IN ADDITION...UNDER AMPLE 850MB THETA-E ADVECTION
SOUTHEAST...LOW-LEVEL LIFT AND CONVERGENCE INCREASE UNDER WEAK
DIFFLUENCE ALOFT IN VICINITY OF THE JET. MODEL SOUNDINGS FROM THE
RUC...WHILE SHOWING THE LOW-LEVEL DRY AIR ON THE 12Z UPPER-AIR
ANALYSIS OVER THE CAROLINAS AND TO THE SOUTHWEST...RAPIDLY MOISTEN
PARTICULARLY BETWEEN 21Z AND 00Z. RADAR TRENDS UPSTREAM SHOW THE DRY
AIR WILL BE TOUGH TO OVERCOME...BUT ANTICIPATE ENOUGH LIFT LATE IN
THE DAY TO EDGE LATE-DAY CHANCES TO LIKELY MAINLY NEAR KMEB...
KFAY...AND KCTZ...WITH ONLY CHANCES TO ABOUT KJNX AND KGSB.
ELSEWHERE...THERE COULD BE ENOUGH MID-LEVEL MOISTURE AND LIFT FOR
SPRINKLES AS THE MID-LEVEL WAVE MOVES THROUGH THE AREA...WITH MODEL
SOUNDINGS FROM BOTH THE LATEST NAM AND RUC SUGGESTIVE OF DECENT
MOISTURE IN THE -10C TO -15C RANGE ALOFT. GIVEN THE RAPID ADVECTION
OF CLOUD COVER...NUDGED MAXES DOWN TO NEAR THE COLDEST GUIDANCE. -DJF
TONIGHT:
FORCING FOR ASCENT TONIGHT WILL BE A COMBINATION OF DPVA/HEIGHT
FALLS ASSOCIATED WITH THE UPPER LEVEL DISTURBANCE TRACKING ACROSS
THE AREA...LOW-LEVEL CONVERGENCE ASSOC/W THE ATTENDANT LOW-LEVEL
TROUGH...AND A NARROW CORRIDOR OF STRONGER WARM ADVECTION IN ADVANCE
OF THE LOW-LEVEL TROUGH. COMPARED TO YESTERDAY...THE LATEST 00Z
GUIDANCE INDICATES A RELATIVE BETTER CHANCE FOR BACKED LOW-LEVEL
FLOW (AND STRONGER WARM ADVECTION) OVER THE EASTERN CAROLINAS IN
ADVANCE OF THE APPROACHING LOW-LEVEL TROUGH BETWEEN 00-06Z TONIGHT.
HOWEVER...THE 00Z GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH
THE EVOLUTION OF THE LOW-LEVEL HEIGHT/WIND FIELDS OVER THE CENTRAL/
EASTERN CAROLINAS...AND THIS LENDS A FAIR AMOUNT OF UNCERTAINTY TO
THE PRECIP FORECAST. THE 00Z GFS/NAM SHOW ANYWHERE FROM 0.10" TO
0.50" OF RAIN EAST OF I-95...WHILE THE 00Z ECMWF SHOWS BARELY A
HUNDREDTH IN THE COASTAL PLAIN AND DRY ELSEWHERE. WITH THE ABOVE IN
MIND...HAVE MADE SOME CHANGES TO THE PREVIOUS FORECAST...CONFINING
THE HIGHEST PRECIP CHANCES (60-70%) EAST OF I-95...TAPERING TO
SLIGHT/LOW CHANCE JUST WEST OF THE HWY 1 CORRIDOR. EXPECT PRECIP
AMOUNTS OF 0.10" OR LESS...HIGHEST EAST OF I-95...ALTHOUGH LOCALLY
HIGHER AMOUNTS WILL BE POSSIBLE IF THE GFS/NAM SOLUTIONS ARE CLOSER
TO REALITY THAN THE ECMWF. WITH MOST OF THE FORCING CONFINED TO THE
MID/UPPER LEVELS IN THE NW PIEDMONT AND A DRY ANTECEDENT LOW/MID
LEVEL AIRMASS IN PLACE...HAVE OPTED TO KEEP THE FCST DRY IN THE
TRIAD...ASIDE FROM A SLIGHT CHANCE OF SPRINKLES. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM FRIDAY...
OVERVIEW:
THE AFOREMENTIONED UPPER LEVEL DISTURBANCE WILL MOVE OFFSHORE BY 12Z
SAT. HOWEVER...A POTENT/AMPLIFYING UPPER LEVEL TROUGH WILL DIG
SOUTHEAST THROUGH THE GREAT LAKES/OH VALLEY INTO THE CENTRAL
APPALACHIANS SATURDAY MORNING...INTO THE MID-ATLANTIC/CAROLINAS
SATURDAY AFT/EVE...AND OFFSHORE THE CAROLINA COAST BY 12Z SUN
MORNING. THE LOW PRESSURE SYSTEM DEVELOPING ALONG THE CAROLINA COAST
TONIGHT IS EXPECTED TO RAPIDLY INTENSIFY SAT/SAT NIGHT AS IT TRACKS
NORTHEAST OFFSHORE THE NEW ENGLAND COAST INTO THE CANADIAN
MARITIMES...WHILE STRONG (1040-1045 MB) HIGH PRESSURE PUSHES SOUTH
THROUGH THE CENTRAL PLAINS AND BUILDS EAST TOWARD THE CAROLINAS AND
MID-ATLANTIC. A STRONG ARCTIC COLD FRONT WILL BE PRESENT AT THE
LEADING EDGE OF THE SFC HIGH BUILDING INTO THE AREA...WITH THE
FRONTAL PASSAGE OCCURRING RAPIDLY DURING MID/LATE SAT AFTERNOON.
TEMPERATURES:
DIFFICULT HIGH TEMP FCST SATURDAY. HIGHS WILL BE DRIVEN PRIMARILY BY
THE TIMING OF THE ARCTIC COLD FRONTAL PASSAGE. THE 00Z GUIDANCE IS
IN GOOD AGREEMENT SHOWING FROPA BETWEEN ROUGHLY 18-21Z SAT
AFTERNOON...WITH 1000-850 MB THICKNESSES RAPIDLY PLUMMETING FROM
1300-1330 METERS (NW-SE) TO 1260-1290 METERS BY 00Z SUNDAY. EXPECT
HIGHS TO OCCUR BY ~18Z WEST OF HIGHWAY 1...WITH TEMPS RAPIDLY
FALLING DURING THE MID/LATE AFTERNOON. EAST OF HIGHWAY 1...HIGHS
WILL OCCUR JUST PRIOR TO THE FRONTAL PASSAGE BETWEEN 17-20Z...WITH
TEMPS RAPIDLY FALLING BY LATE AFTERNOON. WITH THE ABOVE IN
MIND...WILL INDICATE HIGHS RANGING FROM THE LOWER/MID 40S IN THE NW
PIEDMONT TO THE LOWER/MID 50S IN THE SE COASTAL PLAIN. LOWS SAT
NIGHT WILL BE DRIVEN BY STRONG COLD ADVECTION. WITH THICKNESSES
~1250-1260 METERS EVERYWHERE BY 12Z SUN...EXPECT LOWS RANGING FROM
THE UPPER TEENS TO LOWER 20S NW PIEDMONT TO THE LOWER/MID 20S
ELSEWHERE.
PRECIPITATION:
WITH LOW-LEVEL DRYING IN THE WAKE OF THE SURFACE LOW TRACKING
NORTHEAST AWAY FROM THE CAROLINA COAST SATURDAY MORNING AND
STRENGTHENING WESTERLY FLOW/COLD ADVECTION IN THE LOWER LEVELS...
ANTICIPATE LITTLE CHANCE FOR PRECIP ON SATURDAY. HAVING SAID
THAT...SEVERAL POSITIVE FACTORS COULD OVERCOME THE NEGATIVE AND
RESULT IN ISOLD SHOWER ACTIVITY SATURDAY AFTERNOON. ALTHOUGH
LOW-LEVEL FLOW WILL BE UNIDIRECTIONAL...STRONG PRESSURE RISES
APPROACHING FROM THE WEST AS THE SFC HIGH BUILDS TOWARD THE AREA
WILL RESULT IN LOW-LEVEL SPEED CONVERGENCE ALONG THE LEADING EDGE OF
THE FRONT. IN THE UPPER LEVELS...PRODIGIOUS DPVA/HEIGHT FALLS WILL
BE PRESENT DURING THE DAY IN ASSOC/W THE AMPLIFYING UPPER LEVEL
TROUGH DIGGING INTO THE CAROLINAS. ADDITIONALLY...STRONG LOW-LEVEL
COLD ADVECTION COMBINED WITH VERY STRONG LAYER-LIFTING ASSOC/W THE
AMPLIFYING UPPER LEVEL TROUGH WILL RESULT IN STEEPENING LOW/MID
LEVEL LAPSE RATES DURING PEAK HEATING SATURDAY...POTENTIALLY
YIELDING A SMALL AMOUNT OF SFC-BASED INSTABILITY. WITH THE ABOVE IN
MIND...AND THE FACT THAT ALL OF THIS WILL BE COMING TOGETHER DURING
OR CLOSE-TO PEAK HEATING (EXCEPT FOR THE NW PIEDMONT)...WILL
INDICATE A SLIGHT CHANCE OF SHOWERS SAT AFTERNOON ALONG AND EAST OF
HWY 1.
WIND:
STRONG PRESSURE RISES ARE EXPECTED IN THE IMMEDIATE WAKE OF THE
ARCTIC COLD FRONT SATURDAY AFTERNOON/EVENING...AS MUCH AS 6MB/3HR.
ADDITIONALLY...THE AMPLIFYING UPPER LEVEL TROUGH IS PROGGED TO DIG
SOUTHEAST INTO THE CAROLINAS COINCIDENT WITH THE STRONGEST PRESSURE
RISES...ALLOWING FOR DEEPER MIXING VIA STEEPENING OF BOTH THE LOW
AND MID-LEVEL LAPSE RATES. FCST SOUNDINGS SHOW 40-50 KT NW FLOW AS
LOW AS 925 MB SAT AFT/EVE. WITH THE ABOVE IN MIND...THERE IS AT
LEAST A POTENTIAL FOR STRONG NW WINDS SATURDAY AFTERNOON/EVENING...
BETWEEN 4 PM AND MIDNIGHT. SUSTAINED WINDS OF 20-30 MPH WITH GUSTS
UP TO 40 MPH ARE EXPECTED WITH THE STRONGEST PRESSURE RISES...WITH A
POTENTIAL FOR OCCASIONAL/SPORADIC HIGHER GUSTS. ADDITIONALLY...
SHOULD ANY ISOLD SHOWER ACTIVITY DEVELOP DURING PEAK HEATING...
STRONGER FLOW ALOFT COULD BE TRANSPORTED TO THE GROUND. -VINCENT
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 304 AM FRIDAY...
VERY DRY AND COLD SUNDAY...FOLLOWED BY GRADUAL WARMING INTO
MID-WEEK.
THE HEART OF THE STRONG (~1040 MB) COLD SURFACE HIGH PRESSURE IS
FORECAST TO MOVE FROM THE MISSISSIPPI VALLEY EAST TO OUR OUR REGION
BY EARLY MONDAY. A BRISK COLD SUNDAY IS FORECAST AS THE PRESSURE
GRADIENT IS FORECAST TO FINALLY WEAKEN LATE IN THE DAY AS THE HIGH
PRESSURE APPROACHES. LITTLE CHANGE WAS NOTED IN THE FORECAST LOW
LEVEL THICKNESSES AND THE CAA PATTERN FROM PREVIOUS FORECASTS.
THEREFORE... HIGHS IN THE UPPER 30S IN THE NW PIEDMONT RANGING TO
42-43 IN THE SANDHILLS IS EXPECTED.
THE MAIN WEATHER HAZARD WILL BE THE WIND CHILL READINGS SUNDAY
MORNING. THEY ARE FORECAST TO RANGE BETWEEN 10 AND 15 EXCEPT 5 TO 10
DEGREES BETWEEN SUNRISE AND NOON IN THE WINSTON-SALEM AND
GREENSBORO AREAS. AGAIN... THE MOST BLUSTERY CONDITIONS ARE EXPECTED
DURING SUNDAY MORNING WITH WNW WINDS AT 10-15 MPH SUSTAINED... WITH
GUSTS TO 25 MPH. WINDS DURING THE AFTERNOON WILL GRADUALLY DIMINISH.
THIS WILL CONTINUE TO BE HIGHLIGHTED IN THE HAZARDOUS WEATHER
OUTLOOK.
AS THE HIGH SETTLES OVERHEAD SUNDAY NIGHT... IT WILL BE CLEAR WITH A
HARD FREEZE. LOWS SHOULD BE IN THE 20-23 RANGE WITH PLENTY OF
OPPORTUNITY FOR THE RURAL AREAS OF THE PIEDMONT AND SANDHILLS TO DIP
INTO THE UPPER TEENS WITH THE CALM DRY CONDITIONS EXPECTED.
MONDAY AND TUESDAY...
ANOTHER BIG CHANGE IS FORECAST FROM COLD AND DRY MONDAY TO MILDER
CONDITIONS TUESDAY. THIS OCCURS AS THE MODELS SHOW THE COLD UPPER
TROUGH LIFTING OUT RAPIDLY MONDAY... FOLLOWED CLOSELY BY THE COLD
SURFACE HIGHS EXIT OFF THE COAST BY MONDAY NIGHT. IN ADDITION...
MODELS AND ENSEMBLES CONTINUE TO WAVER ON THE STRENGTH AND TRACK OF
A DAMPENING MID-UPPER LEVEL DISTURBANCE THAT IS FORECAST TO TRACK
RAPIDLY EAST ACROSS THE NORTHERN GULF COAST STATES INTO THE TN
VALLEY LATE MONDAY. THE FAVORED EC ACTUALLY DAMPENS THIS WAVE IN THE
INCREASINGLY ZONAL FLOW ALOFT BY THE TIME IT REACHES THE
APPALACHIANS EARLY TUESDAY IN SO MUCH THAT IT DEPICTS ZERO QPF OVER
OUR REGION TUESDAY. THIS SOLUTION HAS SUPPORT FROM THE GFS AND
ENSEMBLE FORECASTS WHICH ALL DEPICT VERY LITTLE IN THE WAY OF QPF
FOR OUR AREA TUESDAY. IT MAKES SENSE IF THE MID-UPPER DISTURBANCE
WEAKENS AS MUCH AS FORECAST. IN ADDITION... THE LOW LEVEL SUB-CLOUD
LAYER IS FORECAST TO BE DRY TUESDAY... DUE TO THE LINGERING AFFECTS
OF THE COLD DRY POLAR HIGH THAT WILL BE JUST OUT TO SEA AT THAT
TIME. WE WILL LEAVE CURRENT POP IN AS CURRENTLY ADVERTISED WITH A
SLIM CHANCE OF LIGHT RAIN TUESDAY. THE P-TYPE WOULD LIKELY BE RAIN
(WITH HIGH CONFIDENCE) IF WE DO GET ANY MEASURABLE PRECIP. THIS
GIVEN THE FORECAST WARMING ALOFT WITH MID LEVEL THICKNESSES IN THE
1550+ RANGE AND RISING BETWEEN 12Z-18Z... AND THE LOW LEVEL
THICKNESSES IN THE 1310M RANGE AND RISING. SENSIBLE WEATHER...
MOSTLY SUNNY & CHILLY MONDAY. HIGHS 47-52. INCREASING CLOUDS LATE
MONDAY AND MONDAY NIGHT WITH LOWS IN THE 30S. MOSTLY CLOUDY TUESDAY
WITH A SLIM CHANCE OF LIGHT RAIN. HIGHS IN THE 40S AND 50S NE TO S.
FOR TUESDAY NIGHT THROUGH THURSDAY...
MILD. VARIABLY CLOUDY. A NEW STORM WITH A VERY WARM LOOK FOR OUR
REGION EXPECTED LATE WEEK. MAIN STORM TRACK IS FAVORED EITHER ALONG
THE APPALACHIANS OR JUST TO THE WEST. WE WILL KEEP POP EITHER LOW OR
OUT OF THE FORECAST SINCE THIS WILL BE DAYS 6-8 OUT IN WHICH THE
NEXT MAIN STORM IS EXPECTED TO APPROACH NC.
SENSIBLE WEATHER... LOWS WEDNESDAY AND THURSDAY IN THE 40S. HIGHS
WEDNESDAY AND THURSDAY IN THE UPPER 50S TO MID 60S.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 110 PM FRIDAY...
PRIMARY AVIATION IMPACTS THROUGH THE 18Z VALID TAF PERIOD WILL BE
GOOD POTENTIAL FOR PERIODS OF IFR CONDITIONS PARTICULARLY WITH
CEILINGS TONIGHT AT KRWI AND KFAY...AND INCREASE IN WIND SPEEDS
SATURDAY. WHERE THE AIR MASS WILL BE MORE MOIST...THE IFR CEILINGS
SHOULD BE MORE PERSISTENT TOWARD KRWI...AND WHILE NOT CURRENTLY
LIKELY...A FEW LOW CLOUDS AND POSSIBLY A BRIEF INSTANCE OF IFR
CONDITIONS COULD OCCUR AS FAR WEST AS ABOUT KRDU. IN THE INTERSTATE
95 CORRIDOR WILL BE THE GREATEST CHANCES FOR RAIN TONIGHT...FOLLOWED
BY GRADUAL DRYING AS WINDS VEER TO A MORE WEST AND NORTHWEST
COMPONENT OVERNIGHT.
WINDS FROM 290 TO 320 WILL INCREASE IN SPEED DURING THE DAY SATURDAY
AS A STRONG FRONT MOVES THROUGH. THE GREATEST THICKNESS PACKING AND
LIKELY ONSET OF MORE GUSTY WINDS SHOULD BE RIGHT AROUND 18Z TOWARD
KINT AND KGSO...AND BY 20Z THROUGHOUT THE REST OF CENTRAL NORTH
CAROLINA. BEFORE NIGHTFALL...PARTICULARLY FROM THE TRIAD TOWARD
KRDU...A FEW WIND GUSTS SHOULD APPROACH 35KT. THICKNESS PACKING
RELAXES SOME OVERNIGHT SATURDAY...BUT THE GRADIENT SHOULD BE TIGHT
ENOUGH UNDER THE AXIS OF THE UPPER TROUGH THAT GUSTY WINDS PERSIST
WELL INTO THE OVERNIGHT HOURS...THOUGH CURRENTLY NOT EXPECTED TO THE
DEGREE THEY WILL BE IN SOME AREAS SATURDAY AFTERNOON.
SUNDAY ONWARD...SEASONABLY GUSTY WINDS SUNDAY FROM THE NORTHWEST TO
20 TO 25KT UNDER VFR CONDITIONS. THE NEXT CHANCE OF SUB-VFR
CONDITIONS SHOULD BE TUESDAY NIGHT. THEN...INTO WEDNESDAY...THERE
MAY BE SUFFICIENT MOISTURE IN WARM-AIR ADVECTION FOR THE DEVELOPMENT
OF LOW CLOUDS IN PARTICULAR...BASED ON FORECAST UPPER-AIR SOUNDINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...DJF
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1014 AM CST FRI FEB 10 2012
.DISCUSSION...
TEMPS ACROSS THE BLACK FIELDS OF SOUTHEAST ND ARE ALREADY
RECOVERING THIS MORNING WITH GWINNER AT -2F. WILL KEEP THE
PREVIOUS SHIFTS IDEA OF WARMEST TEMPS OVER SOUTHEAST ND AND THE
TREES OF MN AND COOLEST TEMPS ACROSS THE SNOWPACK. MADE NO CHANGES
TO HIGH TEMPS BUT DID ADJUST THE MORNING RISE A BIT. DESPITE THE
EXTREME COLD WARNING EXPIRING IT WILL REMAIN PLENTY FRIGID
OUTDOORS TODAY.
&&
.AVIATION...
DO NOT REALLY EXPECT ANY CLOUD COVER THRU THE TAF PERIOD AND NORTH
WINDS SHOULD CONTINUE A SLOW DECREASE.
&&
.PREV DISCUSSION... /ISSUED 256 AM CST FRI FEB 10 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PRIMARY CHALLENGE IS WIND CHILL VALUES AND ASSOCIATED HEADLINES
THIS MORNING AND AGAIN EARLY SATURDAY. WITH NO PRECIPITATION
THROUGH THE WEEKEND...TEMPERATURES WILL BE THE MAIN FOCUS
THEREAFTER. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND WILL USE A
MODEL BLEND FOR THIS FORECAST PACKAGE.
08 UTC OBSERVATIONS ALREADY SHOWING WIND CHILL VALUES IN THE 30 TO
35 BELOW RANGE ALONG AND NORTH OF THE HIGHWAY TWO CORRIDOR. RUC 925
HPA TEMPERATURES DROP TO -25 C BY 12 UTC THIS MORNING ACROSS MUCH
OF THE NORTHERN FORECAST AREA...SO AIR TEMPERATURES STILL EXPECTED
TO DROP ANOTHER 5 TO 8 DEGREES THIS MORNING BEFORE RECOVERING.
SURFACE PRESSURE GRADIENT DOES NOT WEAKEN UNTIL LATER IN THE
DAY...SO NORTH WINDS FROM 10 TO 20 MPH WILL CONTINUE THROUGH AT
LEAST MID-MORNING. ALL THIS TO SAY...WILL ISSUE AN EXTREME COLD
WARNING FOR THE NORTHERN HALF OF THE FORECAST AREA FROM 09 UTC TO
16 UTC THIS MORNING WITH WIND CHILL VALUES IN THE 30 TO 40 BELOW
RANGE.
FOR THE REST OF THE DAY...EXPECT MOSTLY SUNNY CONDITIONS. WINDS
WILL WEAKEN A BIT THIS AFTERNOON...BUT TEMPERATURES WILL BE SLOW
TO RISE WITH AFTERNOON HIGHS IN THE SINGLE DIGITS ABOVE ZERO. SOME
PLACES WITH SNOW COVER WILL LIKELY STRUGGLE TO BREAK THE ZERO
MARK.
ATTENTION THEN TURNS TO SATURDAY MORNING. AIR TEMPERATURES LOOK TO
BE SIMILAR TO THIS MORNING (-10 TO -15 F)...BUT WITH A WEAKENING
PRESSURE GRADIENT AS CENTER OF SURFACE HIGH MOVES ACROSS THE
CENTRAL DAKOTAS...NORTHWEST WIND SHOULD STAY IN THE 5 TO 10 MPH
RANGE. WIND CHILL VALUES APPROACH 30 BELOW IN SPOTS...BUT DOES NOT
APPEAR TO BE AS WIDESPREAD OR QUITE AS COLD AS THIS MORNING. WILL
HOLD OFF ON ANY EXTREME COLD PRODUCTS FOR NOW...BUT SOMETHING THE
DAY SHIFT WILL NEED TO RE-EVALUATE.
SURFACE HIGH PRESSURE CONTINUES ACROSS THE NATION/S MID-SECTION
THROUGH THE WEEKEND WITH A GRADUAL WARMING TREND...SO THAT BY
SUNDAY AFTERNOON HIGHS CLIMB BACK INTO THE LOWER TO MID 20S. DO
NOT FORESEE ANY WIND CHILL PROBLEMS SUNDAY MORNING WITH LOWS IN
THE SINGLE DIGITS ABOVE OR BELOW ZERO AND RELATIVELY LIGHT WIND.
LONG TERM...MONDAY THROUGH THURSDAY NIGHT
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND PLACEMENT OF MINOR
SHORTWAVES MOVING THROUGH DURING THE PERIOD. ALL DETERMINISTIC
RUNS TAKE THE SHORTWAVE ON MONDAY FURTHER SOUTH SO WE STAY DRY. A
MORE SIGNIFICANT SHORTWAVE WILL DIG INTO MANITOBA BY WEDNESDAY AND
INTO THE PLAINS/UPPER MIDWEST ON THURSDAY...ALTHOUGH THERE ARE
STILL QUITE A FEW RUN TO RUN AND INTER-MODEL DIFFERENCES IN
PLACE. ECMWF HAS A SYSTEM COMING THROUGH THE NORTHERN PLAINS ON
FRIDAY AND DROPPING SOME PRECIP...ALTHOUGH WILL HAVE TO KEEP AN
EYE ON IT AS THAT SOLUTION SEEMS TO BE WETTER THAN THE OTHER
DETERMINISTIC MODELS AND MOST ENSEMBLE MEMBERS. TEMPS WILL
CONTINUE TO BE ABOVE SEASONAL AVERAGES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
321 PM EST FRI FEB 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL CARVE OUT ACROSS THE NORTHEAST
AND MID-ATLANTIC STATES THROUGH THE WEEKEND. A SHARP COLD FRONT
ASSOCIATED WITH THE UPPER LEVEL SYSTEM WILL SPREAD ARCTIC AIR INTO
THE COMMONWEALTH...WITH WIDESPREAD LAKE EFFECT AND UPSLOPE SNOW
SHOWERS BRINGING LIGHT TO LOCALLY MODERATE ACCUMULATIONS OVER THE
WESTERN MOUNTAINS INTO SUNDAY. HIGH PRESSURE SHOULD BRING A BRIEF
PERIOD OF FAIR AND DRY CONDITIONS TO START NEXT WEEK...WITH THE
THREAT OF WINTRY PRECIPITATION RETURNING BY NEXT TUESDAY.
TEMPERATURES ARE EXPECTED TO SLOWLY MODERATE OVER THE NEXT SEVEN
DAYS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
SEEDLINGS ALOFT ARE FALLING INTO THE LOW LEVEL MOISTURE/CLOUDS AND
CREATING SOME LIGHT SNOW OVER EASTERN OHIO AND PERHAPS INTO THE
WESTERN PART OF THE STATE. EXTRAPOLATION OF RADAR FEATURES AND
MELDING WITH HRRR DATA AND 12Z NAM PORTRAY A START TO THE SNOW
BEFORE DARK IN THE WESTERN HIGHLANDS AND BY 00Z ALONG THE MD
BORDER WEST OF CHAMBERSBURG. TEMPS ARE CLOSE TO 40 IN THE
SE...AND SLIGHTLY ABOVE FREEZING IN THE CENTRAL MTS. THE WEST AND
NORTH ARE BELOW FREEZING AND 8H TEMPS ARE WELL BELOW ZERO. THE
TEMPS ALOFT IN THE S ARE ALSO BELOW ZERO...BUT THE SFC TEMPS ABOVE
FREEZING AT THE ONSET OF ANY PRECIP IN THE SE WILL SPELL A MIX OF
RAIN AND SNOW. BUT THE TEMPS SHOULD DROP THROUGH THE NIGHT THERE
AND TURN TO ALL SNOW. THE SNOW MIGHT HAVE TROUBLE STICKING AT
FIRST IN THE SE...BUT COOLING AND PERSISTENCE OF THE SNOW WILL
EVENTUALLY WIN OUT. THE TROUGH IS WEAK BUT DEVELOPS EARLY TONIGHT
IN WV/VA AND SLIDES STEADILY TO THE EAST. IT IS THEN ABSORBED INTO
A GREATER TROUGH AND PULLED FAR ENOUGH AWAY TO END THE SNOW IN THE
SE RIGHT AROUND 12Z.
SNOW RATES WILL NOT BE THAT IMPRESSIVE...BUT A BAND OR TWO OF
SNOW WILL PUT TOTALS FOR THE OVERNIGHT AROUND 2 INCHES ACROSS
MOST/ALL OF THE AREA SOUTH OF RTE 22. HILL TOPS COULD GET 3 OR
SO...BUT THESE VALUES DO NOT LOOK WIDESPREAD ENOUGH FOR AN ADVY AT
THIS POINT. THE REST OF THE AREA SHOULD SEE LIGHTER SNOW AMOUNTS
BY MORNING. THE LONG-ADVERTISED ARCTIC FRONT SHOULD NOT IMPACT THE
AREA UNTIL SUNRISE...AS A WAVE DEVELOPS ALONG OR JUST AHEAD OF THE
FRONT IN NRN OH.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
THE SFC WAVE DEVELOPING ALONG THE FRONT WILL SLIDE INTO NWRN PA
LATE TONIGHT...AND DROP THROUGH THE AREA DURING THE DAY ON
SATURDAY - RIGHT ALONG THE LOWERED PRESSURES ON THE FRONT ITSELF.
THERE WILL MOST LIKELY BE A LULL IN THE SHSN OVER THE EAST AND
CENTRAL COS FOR MUCH OF THE MORNING...AND THEN THE FRONT ARRIVES.
BUT WITH LESS FANFARE THAN IN THE WEST. THE KINK IN THE FRONT WILL
PIVOT RIGHT OVERHEAD AND THIS WILL CREATE A SLOWER PROGRESSION TO
THE FRONT ACROSS THE AREA THAN HAD BEEN ANTICIPATED...BUT THE
EFFECTS SHOULD BE THE SAME WHEN IT DOES GET HERE. IN FACT...THE
SQUALLS COULD BE A LITTLE MORE INTENSE WITH LAPSE RATES PERHAPS
GETTING A LITTLE STEEPER DUE TO A TINY BIT MORE SFC HEATING BEFORE
THE FRONT REACHES THE WRN/CENT MTS. THE 8H TEMPS DROP
PRECIPITOUSLY THROUGH THE AFTERNOON IN THE WEST BUT NOT UNTIL
LATER IN THE DAY OR EVENING FOR THE CENTRAL MTS. WILL THEREFORE
PAINT JUST MAINLY STEADY TEMPS OR EVEN A SLIGHT MORNING BUMP
UPWARD IN MOST PLACES AND A MORE-NORMAL DIURNAL CURVE IN THE
SOUTHEAST.
ADVISORY AMOUNT SNOWS OF A WIDESPREAD 3 INCHES OR MORE IN 12 HRS
TIME WILL BE TOUGH TO FIND ANYWHERE. BUT THE WESTERN HIGHLANDS
WILL HAVE THE WORST OF THE CONDITIONS OVERALL...BUT NOT UNTIL
DURING THE DAYLIGHT HRS WHEN THE FRONT AND ASSOCD SHSN/SQUALLS
ARRIVE. THE CONDITIONS WILL NOT BE /BAD/ DUE ONLY TO SNOW AMOUNTS
NEAR 3 INCHES - WHICH AGAIN WILL BE HARD TO FIND - BUT FOR THE
COMBINATION OF SNOW...WIND AND POSSIBLY ICY ROADS AS THE FRONT
PASSES. THUS...WILL HOLD OFF ON ANY ADVYS FOR THE REST OF THE
AREA AT THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE MODELS ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE SHARP H5
TROF AXIS CROSSING CENTRAL PA SAT NGT...ACCOMPANIED BY -16 TO -18C
AIR AT H85 WHICH IS -1 TO -2SD BELOW NORMAL -- BUT NOT UNUSUAL FOR
THE MIDDLE OF FEBRUARY. BLUSTERY NW WINDS WILL DIRECT SLIGHTLY
MODIFIED ARCTIC AIR INTO THE REGION...PLUMMETING TEMPERATURES INTO
THE SINGLE DIGITS AND TEENS AND DROPPING WIND CHILLS NEAR TO BELOW
ZERO. STRONG LG SCALE LIFT AND STEEP MID-LEVEL LAPSE RATES WITH THE
TROF SHOULD ALLOW SNOW SHOWERS TO REACH INTO THE LWR SUSQ VLY/SERN
PA. CHANNELED NORTHWEST FLOW IN THE WAKE OF THE TROF WILL PRODUCE
LAKE EFFECT AND UPSLOPE SNOWS OVER THE LAUREL HIGHLANDS AND NW
MTNS...WITH ADDITIONAL LIGHT TO LOCALLY MODERATE ACCUMULATIONS
EXPECTED THRU SUNDAY.
CONCERNING THE MID-UPPER LEVEL FLOW ACRS THE NERN CONUS/SERN CANADA
SUNDAY INTO MONDAY...THERE IS STILL SOME SPREAD WITH TROF AMPLITUDE
AND TRACK OF THE EMBEDDED CLOSED LOW. THE NAM LEANS TO THE NRN SIDE
OF THE SPREAD WITH THE CLOSED LOW IN NRN QUEBEC AND EVENTUALLY
BECOMES FLATTER THAN THE GUIDANCE AVERAGE...WHILE THE CANADIAN GLBL
AND ECMWF DEFINE THE SRN SIDE OF THE ENVELOPE SHOWING THE CLOSED LOW
CENTERED JUST NE OF MAINE. GOOD CONTINUITY OF AN INTERMEDIATE TRACK
WITHIN THE SOLN SPREAD FOR THE CLOSED LOW LEADS TO RECOMMENDATION OF
A GFS/ECMWF COMPROMISE. THE MINOR MODEL DIFFS IN HANDLING THE POLAR
VORTEX SHOULD NOT HAVE MUCH OF AN IMPACT ON THE SENSIBLE WEATHER IN PA
WITH CONDITIONS REMAINING SEASONABLY COLD AND BRISK ON SUNDAY...WITH
SNOW SHOWERS BECOMING LIGHTER AND LESS WIDESPREAD INTO EARLY NEXT
WEEK AS SFC HIGH PRES SLIDES EWD FM THE MS/TN VLY.
FOLLOWING A BRIEF PERIOD OF FAIR AND DRY WX TO START OFF NEXT WEEK
THE THREAT OF LIGHT PCPN WILL RETURN TO THE FORECAST FROM LATE MON
NGT/EARLY TUES INTO WED...WITH PERHAPS A MORE SIGNIFICANT STORM
SYSTEM AFFECTING THE REGION SOMETIME LATE NEXT WEEK. THE 10/12Z
OPERATIONAL MODEL AND ENSEMBLE GUIDANCE STILL SHOWS UNCERTAINTY WITH
SHORTWAVE TIMING AND POTENTIAL PHASING OF STREAMS. THE SPLIT FLOW IS
IS WREAKING HAVOC WITH THE MODEL SOLUTIONS. AFTER A TASTE OF WINTER
THIS WEEKEND...EXPECT TEMPERATURES TO SLOWLY MODERATE IN TIME
EVENTUALLY CLIMBING BACK NEAR TO SLIGHTLY ABOVE NORMAL BY THE END OF
THE MEDIUM RANGE PD.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
A WEAK WAVE OF LOW PRESSURE WILL MOVE ACROSS THE CENTRAL
APPALACHIANS TONIGHT WHICH SHOULD BRING IFR CIGS AND VSBYS TO JST
LATE THIS EVENING AND THEN INTO MDT/LNS FOR LATER IN THE NIGHT.
MVFR CIGS POSSIBLE OVER THE REST OF THE AREA AS WELL IN -SN. THE
PRECIP AT MDT AND LNS WILL MOST LIKELY START AS RAIN OR SNOW
MELTING TO/MIXING WITH RAIN AS IT FALLS. PRECIP FROM THIS WAVE
SHOULD DIMINISH TO ALLOW FOR AT LEAST MVFR VSBY BEFORE 12Z SAT.
AFTER A BRIEF LULL IN SNOW A STRONG COLD FRONT WILL BRING SNOW
SHOWERS AND SQUALLS SAT MORNING TO THE WRN HIGHLANDS. THEN A
SECONDARY/WEAK LOW IN THE PRESSURES ALONG THE FRONT WHICH DEVELOPS
OVER NRN OH TONIGHT WILL DROP ACROSS THE AREA FROM NW TO SE DURING
THE DAY SAT. THIS AND THE FRONT WILL CREATE SNOW SHOWERS AND
LOCALLY HEAVIER SQUALLS FOR MOST OF THE TERMINALS IN THE LATE
MORNING AND AFTERNOON. BUT THE SHOWERS WILL MOST LIKELY BECOME
MORE SCT AND WEAKER AS THE FRONT DESCENDS INTO THE ERN VALLEYS.
EXPECT GUSTY WINDS...VERY LOW VSBYS AND CIGS IN THE NW HALF /BFD-
JST/ BETWEEN 15 AND 21Z SAT. LOW CIGS AND VSBYS ARE ALSO POSSIBLE
AT IPT-UNV-AOO AS WELL - MAINLY SAT AFTN.
OUTLOOK...
SAT NIGHT-SUN...MVFR/OCNL IFR NW IN SHSN. VFR ELSEWHERE.
MON...MAINLY VFR.
TUE-WED...MVFR IN -SN POSSIBLE. OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST SATURDAY FOR
PAZ004-005-010-017-024-033.
&&
$$
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
308 PM EST FRI FEB 10 2012
.SYNOPSIS...
HIGH PRESSURE SLIDE TO THE CAROLINA COAST WHILE A TROUGH OF LOW
PRESSURE DEVELOPS THE THE SOUTH OF THE STATE. THAT TROUGH WILL
MOVE TO THE EAST LATER TONIGHT AND WILL MAKE LIGHT SNOW ACROSS
MUCH OF THE AREA...WITH THE HIGHEST AMOUNTS ACROSS THE SOUTHERN
HALF OF THE AREA. A SHARPENING UPPER LEVEL TROUGH OVER EASTERN
CANADA AND THE NORTHEASTERN STATES WILL SEND A STRONG COLD FRONT
ACROSS THE STATE ON SATURDAY. THE FRONT WILL GENERATE WIDESPREAD
SNOW SHOWERS AND A FEW HEAVIER SQUALLS...AND A MODERATE SNOWFALL
IN THE WESTERN MOUNTAINS. BEHIND THE FRONT...MODIFIED ARCTIC AIR
WILL POUR INTO THE REGION FOR THE WEEKEND...AND GENERATE LAKE
EFFECT SNOW. THE TEMPERATURES WILL MODERATE BY MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SEEDLINGS ALOFT ARE FALLING INTO THE LOW LEVEL MOISTURE/CLOUDS AND
CREATING SOME LIGHT SNOW OVER EASTERN OHIO AND PERHAPS INTO THE
WESTERN PART OF THE STATE. EXTRAPOLATION OF RADAR FEATURES AND
MELDING WITH HRRR DATA AND 12Z NAM PORTRAY A START TO THE SNOW
BEFORE DARK IN THE WESTERN HIGHLANDS AND BY 00Z ALONG THE MD
BORDER WEST OF CHAMBERSBURG. TEMPS ARE CLOSE TO 40 IN THE
SE...AND SLIGHTLY ABOVE FREEZING IN THE CENTRAL MTS. THE WEST AND
NORTH ARE BELOW FREEZING AND 8H TEMPS ARE WELL BELOW ZERO. THE
TEMPS ALOFT IN THE S ARE ALSO BELOW ZERO...BUT THE SFC TEMPS ABOVE
FREEZING AT THE ONSET OF ANY PRECIP IN THE SE WILL SPELL A MIX OF
RAIN AND SNOW. BUT THE TEMPS SHOULD DROP THROUGH THE NIGHT THERE
AND TURN TO ALL SNOW. THE SNOW MIGHT HAVE TROUBLE STICKING AT
FIRST IN THE SE...BUT COOLING AND PERSISTENCE OF THE SNOW WILL
EVENTUALLY WIN OUT. THE TROUGH IS WEAK BUT DEVELOPS EARLY TONIGHT
IN WV/VA AND SLIDES STEADILY TO THE EAST. IT IS THEN ABSORBED INTO
A GREATER TROUGH AND PULLED FAR ENOUGH AWAY TO END THE SNOW IN THE
SE RIGHT AROUND 12Z.
SNOW RATES WILL NOT BE THAT IMPRESSIVE...BUT A BAND OR TWO OF
SNOW WILL PUT TOTALS FOR THE OVERNIGHT AROUND 2 INCHES ACROSS
MOST/ALL OF THE AREA SOUTH OF RTE 22. HILL TOPS COULD GET 3 OR
SO...BUT THESE VALUES DO NOT LOOK WIDESPREAD ENOUGH FOR AN ADVY AT
THIS POINT. THE REST OF THE AREA SHOULD SEE LIGHTER SNOW AMOUNTS
BY MORNING. THE LONG-ADVERTISED ARCTIC FRONT SHOULD NOT IMPACT THE
AREA UNTIL SUNRISE...AS A WAVE DEVELOPS ALONG OR JUST AHEAD OF THE
FRONT IN NRN OH.
&&
.SHORT TERM /SATURDAY/...
THE SFC WAVE DEVELOPING ALONG THE FRONT WILL SLIDE INTO NWRN PA
LATE TONIGHT...AND DROP THROUGH THE AREA DURING THE DAY ON
SATURDAY - RIGHT ALONG THE LOWERED PRESSURES ON THE FRONT ITSELF.
THERE WILL MOST LIKELY BE A LULL IN THE SHSN OVER THE EAST AND
CENTRAL COS FOR MUCH OF THE MORNING...AND THEN THE FRONT ARRIVES.
BUT WITH LESS FANFARE THAN IN THE WEST. THE KINK IN THE FRONT WILL
PIVOT RIGHT OVERHEAD AND THIS WILL CREATE A SLOWER PROGRESSION TO
THE FRONT ACROSS THE AREA THAN HAD BEEN ANTICIPATED...BUT THE
EFFECTS SHOULD BE THE SAME WHEN IT DOES GET HERE. IN FACT...THE
SQUALLS COULD BE A LITTLE MORE INTENSE WITH LAPSE RATES PERHAPS
GETTING A LITTLE STEEPER DUE TO A TINY BIT MORE SFC HEATING BEFORE
THE FRONT REACHES THE WRN/CENT MTS. THE 8H TEMPS DROP
PRECIPITOUSLY THROUGH THE AFTERNOON IN THE WEST BUT NOT UNTIL
LATER IN THE DAY OR EVENING FOR THE CENTRAL MTS. WILL THEREFORE
PAINT JUST MAINLY STEADY TEMPS OR EVEN A SLIGHT MORNING BUMP
UPWARD IN MOST PLACES AND A MORE-NORMAL DIURNAL CURVE IN THE
SOUTHEAST.
ADVISORY AMOUNT SNOWS OF A WIDESPREAD 3 INCHES OR MORE IN 12 HRS
TIME WILL BE TOUGH TO FIND ANYWHERE. BUT THE WESTERN HIGHLANDS
WILL HAVE THE WORST OF THE CONDITIONS OVERALL...BUT NOT UNTIL
DURING THE DAYLIGHT HRS WHEN THE FRONT AND ASSOCD SHSN/SQUALLS
ARRIVE. THE CONDITIONS WILL NOT BE /BAD/ DUE ONLY TO SNOW AMOUNTS
NEAR 3 INCHES - WHICH AGAIN WILL BE HARD TO FIND - BUT FOR THE
COMBINATION OF SNOW...WIND AND POSSIBLY ICY ROADS AS THE FRONT
PASSES. THUS...WILL HOLD OFF ON ANY ADVYS FOR THE REST OF THE
AREA AT THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE MODELS ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE SHARP H5
TROF AXIS CROSSING CENTRAL PA SAT NGT...ACCOMPANIED BY -16 TO -18C
AIR AT H85 WHICH IS -1 TO -2SD BELOW NORMAL -- BUT NOT UNUSUAL FOR
THE MIDDLE OF FEBRUARY. BLUSTERY NW WINDS WILL DIRECT SLIGHTLY
MODIFIED ARCTIC AIR INTO THE REGION...PLUMMETING TEMPERATURES INTO
THE SINGLE DIGITS AND TEENS AND DROPPING WIND CHILLS NEAR TO BELOW
ZERO. STRONG LG SCALE LIFT AND STEEP MID-LEVEL LAPSE RATES WITH THE
TROF SHOULD ALLOW SNOW SHOWERS TO REACH INTO THE LWR SUSQ VLY/SERN
PA. CHANNELED NORTHWEST FLOW IN THE WAKE OF THE TROF WILL PRODUCE
LAKE EFFECT AND UPSLOPE SNOWS OVER THE LAUREL HIGHLANDS AND NW
MTNS...WITH ADDITIONAL LIGHT TO LOCALLY MODERATE ACCUMULATIONS
EXPECTED THRU SUNDAY.
CONCERNING THE MID-UPPER LEVEL FLOW ACRS THE NERN CONUS/SERN CANADA
SUNDAY INTO MONDAY...THERE IS STILL SOME SPREAD WITH TROF AMPLITUDE
AND TRACK OF THE EMBEDDED CLOSED LOW. THE NAM LEANS TO THE NRN SIDE
OF THE SPREAD WITH THE CLOSED LOW IN NRN QUEBEC AND EVENTUALLY
BECOMES FLATTER THAN THE GUIDANCE AVERAGE...WHILE THE CANADIAN GLBL
AND ECMWF DEFINE THE SRN SIDE OF THE ENVELOPE SHOWING THE CLOSED LOW
CENTERED JUST NE OF MAINE. GOOD CONTINUITY OF AN INTERMEDIATE TRACK
WITHIN THE SOLN SPREAD FOR THE CLOSED LOW LEADS TO RECOMMENDATION OF
A GFS/ECMWF COMPROMISE. THE MINOR MODEL DIFFS IN HANDLING THE POLAR
VORTEX SHOULD NOT HAVE MUCH OF AN IMPACT ON THE SENSIBLE WEATHER IN PA
WITH CONDITIONS REMAINING SEASONABLY COLD AND BRISK ON SUNDAY...WITH
SNOW SHOWERS BECOMING LIGHTER AND LESS WIDESPREAD INTO EARLY NEXT
WEEK AS SFC HIGH PRES SLIDES EWD FM THE MS/TN VLY.
FOLLOWING A BRIEF PERIOD OF FAIR AND DRY WX TO START OFF NEXT WEEK
THE THREAT OF LIGHT PCPN WILL RETURN TO THE FORECAST FROM LATE MON
NGT/EARLY TUES INTO WED...WITH PERHAPS A MORE SIGNIFICANT STORM
SYSTEM AFFECTING THE REGION SOMETIME LATE NEXT WEEK. THE 10/12Z
OPERATIONAL MODEL AND ENSEMBLE GUIDANCE STILL SHOWS UNCERTAINTY WITH
SHORTWAVE TIMING AND POTENTIAL PHASING OF STREAMS. THE SPLIT FLOW IS
IS WREAKING HAVOC WITH THE MODEL SOLUTIONS. AFTER A TASTE OF WINTER
THIS WEEKEND...EXPECT TEMPERATURES TO SLOWLY MODERATE IN TIME
EVENTUALLY CLIMBING BACK NEAR TO SLIGHTLY ABOVE NORMAL BY THE END OF
THE MEDIUM RANGE PD.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
A WEAK WAVE OF LOW PRESSURE WILL MOVE ACROSS THE CENTRAL
APPALACHIANS TONIGHT WHICH SHOULD BRING IFR CIGS AND VSBYS TO JST
LATE THIS EVENING AND THEN INTO MDT/LNS FOR LATER IN THE NIGHT.
MVFR CIGS POSSIBLE OVER THE REST OF THE AREA AS WELL IN -SN. THE
PRECIP AT MDT AND LNS WILL MOST LIKELY START AS RAIN OR SNOW
MELTING TO/MIXING WITH RAIN AS IT FALLS. PRECIP FROM THIS WAVE
SHOULD DIMINISH TO ALLOW FOR AT LEAST MVFR VSBY BEFORE 12Z SAT.
AFTER A BRIEF LULL IN SNOW A STRONG COLD FRONT WILL BRING SNOW
SHOWERS AND SQUALLS SAT MORNING TO THE WRN HIGHLANDS. THEN A
SECONDARY/WEAK LOW IN THE PRESSURES ALONG THE FRONT WHICH DEVELOPS
OVER NRN OH TONIGHT WILL DROP ACROSS THE AREA FROM NW TO SE DURING
THE DAY SAT. THIS AND THE FRONT WILL CREATE SNOW SHOWERS AND
LOCALLY HEAVIER SQUALLS FOR MOST OF THE TERMINALS IN THE LATE
MORNING AND AFTERNOON. BUT THE SHOWERS WILL MOST LIKELY BECOME
MORE SCT AND WEAKER AS THE FRONT DESCENDS INTO THE ERN VALLEYS.
EXPECT GUSTY WINDS...VERY LOW VSBYS AND CIGS IN THE NW HALF /BFD-
JST/ BETWEEN 15 AND 21Z SAT. LOW CIGS AND VSBYS ARE ALSO POSSIBLE
AT IPT-UNV-AOO AS WELL - MAINLY SAT AFTN.
OUTLOOK...
SAT NIGHT-SUN...MVFR/OCNL IFR NW IN SHSN. VFR ELSEWHERE.
MON...MAINLY VFR.
TUE-WED...MVFR IN -SN POSSIBLE. OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1214 PM CST FRI FEB 10 2012
.UPDATE...
A BAND OF MDT TO HEAVY SNOW AND STRONG WINDS VIA LOW LEVEL
FRONTOGENESIS ALONG THE ARCTIC FRONT WILL SWEEP SOUTHWARD THROUGH
THE ERN CWA THROUGH THE EARLY AFTERNOON. INCREASED SNOW AMOUNTS TO
2 TO 3 INCHES WITH THE MOST ALONG THE LAKESHORE WHERE A BRIEF
PERIOD OF LAKE EFFECT SNOW IS EXPECTED BEFORE THE MAIN SNOW BAND
SETS UP OVER THE LAKE ON NLY WINDS. ALSO INCLUDED BLOWING SNOW
WITH THE EXPECTED STRONG WINDS...COLDER TEMPS...AND FALLING SNOW.
THERE MAY BE BRIEF PERIODS OF WHITEOUT CONDITIONS IN THE HEAVIER
SNOW BAND ALONG THE FRONT AS IT PROGRESSES SOUTH THROUGH ERN WI.
WILL BE ISSUING SPECIAL WEATHER STATEMENTS AND GRAPHICASTS TO
HANDLE THE BURST OF SNOW AND WIND TODAY. MOST OF THE ACCUMULATING
SNOW WILL BE OVER BY THE AFTERNOON RUSH HOUR WITH THE EXCEPTION
OF A LAKE EFFECT SNOW BAND FROM FAR SE MKE COUNTY THROUGH WIND
POINT IN RACINE AND ERN KENOSHA COUNTY.
&&
.AVIATION/18Z TAFS/...
HEAVIEST SNOW FROM AROUND MILWAUKEE TO WATERTOWN AND SOUTHWARD WILL
CONTINUE TO MOVE SOUTH INTO THIS AFTERNOON. VSBYS WILL GET DOWN TO
1/4 SM AT TIMES IN THIS HEAVIER AREA. ELSEWHERE SNOW WILL BE
LIGHTER...THOUGH GUSTY NORTH WINDS WILL RESULT IN BLOWING
SNOW...REDUCING VSBYS TO 1/2 TO 1 1/2 SM AT TIMES.
THE SNOW WILL FINALLY WIND NORTH TO SOUTH BY EVENING...WITH MVFR
CIGS LINGERING AT LEAST INTO THE EVENING. THE NAM HAS HIGHER LOW
LEVEL RH STICKING AROUND THROUGH THE NIGHT...SO WILL HAVE TO
CONSIDER KEEPING LOWER CIGS AROUND LATER. WILL HAVE TO EVALUATE
CLOSELY LOOK AT CIGS FOR TOMORROW AS WELL. CURRENTLY HAVE SCATTERED
CLOUDS IN THE FORECAST...BUT THE NAM WANTS TO KEEP THE LOW CLOUDS
GOING RIGHT THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 252 AM CST FRI FEB 10 2012/
VERY SHORT TERM...TODAY AND TONIGHT.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE KENOSHA AREA AROUND NOON.
A MID LEVEL SHORTWAVE WILL DROP SOUTHEAST AND EXTEND ACROSS EASTERN
LAKE SUPERIOR TO FAR SOUTHERN MINNESOTA BY NOON AND PUSH ACROSS
SOUTHEAST WISCONSIN EARLY THIS AFTERNOON. THIS IS SLOWING THE
SOUTHWARD PROGRESSION OF THE FRONT AND ALSO CAUSING WEAK UPWARD
MOTION TO CONTINUE AFTER THE FRONTAL PASSAGE. FORECAST SOUNDINGS
SHOW MOISTURE EXTENDING FROM THE LOW LEVELS THROUGHOUT THE MID
LEVELS. MID LEVELS THEN DRY BEHIND THE 500 MB TROUGH AXIS. AS THIS
HAPPENS LOW LEVEL LAPSE RATES INCREASE TO ALMOST 9 C/KM FROM THE
SURFACE TO 850 MB. THEREFORE EXPECT AN INITIAL SNOW SHOWER
POTENTIAL WITH THE FRONT...BUT SOME LIGHT SNOW SHOWERS/FLURRIES WILL
CONTINUE ACROSS SOUTH CENTRAL WISCONSIN THIS AFTERNOON AND ACROSS
SOUTHEAST WISCONSIN INTO THE EARLY EVENING.
NEXT PROBLEM IS INITIAL LAKE ENHANCEMENT BEHIND THE FRONT. NAM
FORECAST SOUNDINGS GENERATE LAKE ENHANCEMENT WITH AROUND 200 J/KG
OF CAPE EARLY THIS AFTERNOON AND AROUND 300 J/KG LATE THIS AFTERNOON
AND 400 J/KG EARLY THIS EVENING. DELTA T VALUES ARE MARGINAL THIS
AFTERNOON BUT JUMP TO MODERATE THIS EVENING OF -17 C. NAM SOUNDING
INDICATE THAT BY THE TIME THIS HAPPENS WINDS BECOME NORTH ACROSS
MUCH OF THE LOW LEVELS EXCEPT NORTHEAST IN A NARROW LAYER AROUND 4
THSD FT. RUC SOUNDINGS ARE MORE FAVORABLE WITH NNE OR NE WINDS FROM
JUST ABOVE THE SURFACE TO ALMOST 7 THSD FT.
WILL HOLD OFF ON ANY HEADLINES DUE TO THE UNCERTAINTY...BUT WILL
BUMP UP THE SNOW AMOUNTS NEAR THE LAKE.
AFTER MIDNIGHT THE 500 MB TROUGH REACHES LOWER MICHIGAN...AND THE
SOUNDINGS NEAR LAKE MICHIGAN SHOW A PRONOUNCED DRYING ABOVE
3 THSD FT.
SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT.
SPRAWLING...SLOW MOVING HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS
TONIGHT AND SATURDAY AS COLD AIR SETTLES OVER THE REGION. CORE OF
COLDEST AIR WITH 85H TEMPS AROUND -18C SHIFTS SLOWLY EWD ON
SAT...CONTINUING ON SUN AS THE LOW LEVEL WINDS BEGIN TO BACK MORE
NORTHWEST. NEVERTHELESS...DESPITE SUNSHINE DO NOT WANT TO WARM TEMPS
TOO FAST AS BLUSTERY NORTHWEST WINDS WL CONTINUE ON SAT AT THE
SFC...AND SOME AREAS WL LIKELY HAVE A FRESH LIGHT SNOW COVER. MAY BE
ABLE TO MIX TO AROUND 925H BOTH DAYS. HENCE DESPITE COLD BIAS DUE
TO PERSISTENT LACK OF SNOW...WL KEEP HIGHS IN THE 15 TO 20 RANGE
MOST AREAS SAT...AND IN MID-UPR 20S SUN. BLUSTERY NORTHWEST WINDS
OF 15 TO 25KTS WL ADD A STRONG CHILL TO THE AIR ON SAT. WIND CHILLS
WILL DROP TO BTWN 5 AND 15 BLO ZERO EARLY SAT MRNG AND AGAIN LATE
SAT NGT/EARLY SUN MRNG.
PERIOD OF MID-HIGH LEVEL CLOUDS ASSOCD WITH SURGE OF WARM AIR
ADVECTION MAY BRUSH PORTIONS OF SRN WI SAT NGT...BUT MAJORITY OF
CLOUDS REMAIN NORTH.
LONG TERM...MONDAY THROUGH THURSDAY.
EXTENDED GUIDANCE REMAINS IN REASONABLE AGREEMENT THROUGH EARLY
PERIODS. INCREASING SOUTHERLY WINDS ON THE BACKSIDE OF THE LARGE
HIGH PRESSURE AREA ALLOW MOISTURE TO INCREASE TO AROUND 0.4 INCH BY
LATER MONDAY. STRONGEST TEMP/MOISTURE ADVECTION HOWEVER REMAINS TO
THE SOUTH OF WI...HOWEVER ECMWF...GFS AND GEM-NHEM DO INCREASE
MOISTURE TO AT LEAST 10K FEET. ALTHOUGH FORCING REMAINS WEAK AS MID
LEVEL SHORT WAVE MOVES THROUGH MONDAY NIGHT...CONDENSATION PRESSURE
DEFICITS DECREASE TO LESS THAN 10MB ON MONDAY WITH WEAK ISENTROPIC
OMEGA. WITH SLR AROUND 15 TO 1...POSSIBLE FOR AN INCH OR TWO OF
SNOW MONDAY INTO MONDAY NIGHT. ENOUGH CONSISTENCY AND AGREEMENT TO
BUMP UP POPS TO LIKELY OVER MORE OF SRN WI MON AFTN CLOSER TO
STRONGER LOW LEVEL WEAK FORECING...AND IN THE SOUTHEAST MON NGT.
MID LEVEL WEAK WAVE STILL EXPECTED TO SLIDE OFF TO THE EAST BY
TUESDAY... HOWEVER PROGRESS HAS SLOWED A BIT AS SECONDARY WEAK WAVE
MOVES FROM THE UPPER MIDWEST INTO THE CENTRAL MS VALLEY. WL
CONTINUE DRYING TREND INTO TUE...BUT KEEP SCHC POPS IN THE FAR
SOUTHEAST TO REFLECT SLOWER MOVEMENT.
SEVERAL DAYS AGO...THOUGHT WE WERE HEADING TO A MORE UNSETTLED
PERIOD FOR LATER NEXT WEEK...AS MULTIPLE PIECES OF SHORT WAVE ENERGY
WERE EJECTED FROM PERSISTENT NRN PACIFIC LONG WAVE TROUGH INTO
CENTRAL CONUS. HOWEVER LAST DAY OR TWO...TREND HAS BEEN TOWARD
RETURN OF SPLIT FLOW ACROSS CONUS...WITH SRN STREAM REMAINING MORE
ACTIVE FROM TUE INTO THU. ECWMF FIRST TO PICK UP ON DRIER NRN
STREAM SIGNAL...AND LAST SEVERAL RUNS OF GFS NOW BACKING OFF ON
UNSETTLED MID-WEEK WX FOR UPPER MIDWEST. HPC ALSO TRENDING TOWARD
DRIER SOLUTION...FAVORING ECMWF OR ECMWF BLEND. FOR NOW...WL KEEP
POPS VERY LOW FOR LATE PDS WITH LOW CONFIDENCE. END RESULT...PALTRY
WINTER CONDITIONS TO CONTINUE.
AVIATION /12Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE BROUGHT MVFR STRATUS
ACROSS THE FORECAST AREA AND WILL PERSIST EARLY THIS MORNING.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE FAR SOUTHEAST TIP AROUND NOON. MAINLY CIGS
EXPECTED BEHIND THE FRONT ALONG WITH MVFR VSBYS IN SNOW SHOWERS WITH
SOME IFR VSBYS IN THE HEAVIER SNOW SHOWERS. APPEARS LAKE
ENHANCEMENT TO DEVELOP LATE THIS MORNING TOWARD SHEBOYGAN AND
ACROSS SOUTHEAST WISCONSIN FROM MILWAUKEE SOUTH THIS AFTERNOON.
OCCASIONAL IFR VSBYS EXPECTED WITH THIS SNOW. BY EVENING A LAKE
EFFECT SNOW BAND SHOULD SET UP MAINLY OVER WESTERN LAKE MICHIGAN AND
AFFECT AREAS MAINLY SOUTH OF THE ILLINOIS BORDER...BUT THERE IS A
POSSIBILITY OF SOME OF THIS SNOW AFFECTING THE SHORELINE AREAS
MAINLY SOUTH OF MILWAUKEE.
MARINE...
WINDS MAY BRIEFLY DROP BELOW SMALL CRAFT CRITERIA EARLY THIS MORNING
JUST AHEAD OF A TROUGH OF LOW PRESSURE EXTENDING ACROSS NORTHERN
LAKE MICHIGAN. AS AN ASSOCIATED STRONG COLD FRONT DROPS SOUTH
ACROSS SOUTHERN LAKE MICHIGAN LATER THIS MORNING WINDS WILL BECOME
NORTH AND INCREASE DRAMATICALLY. A FEW WIND GUSTS MAY APPROACH GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS.
DUE TO THE COLDER AIR WAVES EXPECTED TO INCREASE RAPIDLY BEHIND THE
FRONT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL OF THE SHORE
AREAS INTO SATURDAY AFTERNOON.
CONFIDENCE...
TODAY AND TONIGHT...MEDIUM.
SATURDAY THROUGH SUNDAY NIGHT...MEDIUM TO HIGH.
MONDAY AND MONDAY NIGHT...MEDIUM TO HIGH.
TUESDAY...MEDIUM.
WEDNESDAY AND THURSDAY...LOW TO MEDIUM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CST SATURDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
UPDATE...GEHRING/DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SATURDAY THROUGH THURSDAY...MBK
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1003 AM CST FRI FEB 10 2012
.UPDATE...
A BAND OF MDT TO HEAVY SNOW AND STRONG WINDS VIA LOW LEVEL
FRONTOGENESIS ALONG THE ARCTIC FRONT WILL SWEEP SOUTHWARD THROUGH
THE ERN CWA THROUGH THE EARLY AFTERNOON. INCREASED SNOW AMOUNTS TO
2 TO 3 INCHES WITH THE MOST ALONG THE LAKESHORE WHERE A BRIEF
PERIOD OF LAKE EFFECT SNOW IS EXPECTED BEFORE THE MAIN SNOW BAND
SETS UP OVER THE LAKE ON NLY WINDS. ALSO INCLUDED BLOWING SNOW
WITH THE EXPECTED STRONG WINDS...COLDER TEMPS...AND FALLING SNOW.
THERE MAY BE BRIEF PERIODS OF WHITEOUT CONDITIONS IN THE HEAVIER
SNOW BAND ALONG THE FRONT AS IT PROGRESSES SOUTH THROUGH ERN WI.
WILL BE ISSUING SPECIAL WEATHER STATEMENTS AND GRAPHICASTS TO
HANDLE THE BURST OF SNOW AND WIND TODAY. MOST OF THE ACCUMULATING
SNOW WILL BE OVER BY THE AFTERNOON RUSH HOUR WITH THE EXCEPTION
OF A LAKE EFFECT SNOW BAND FROM FAR SE MKE COUNTY THROUGH WIND
POINT IN RACINE AND ERN KENOSHA COUNTY.
&&
.AVIATION/18Z TAFS/...
HEAVIEST SNOW FROM AROUND MILWAUKEE TO WATERTOWN AND SOUTHWARD WILL
CONTINUE TO MOVE SOUTH INTO THIS AFTERNOON. VSBYS WILL GET DOWN TO
1/4 SM AT TIMES IN THIS HEAVIER AREA. ELSEWHERE SNOW WILL BE
LIGHTER...THOUGH GUSTY NORTH WINDS WILL RESULT IN BLOWING
SNOW...REDUCING VSBYS TO 1/2 TO 1 1/2 SM AT TIMES.
THE SNOW WILL FINALLY WIND NORTH TO SOUTH BY EVENING...WITH MVFR
CIGS LINGERING AT LEAST INTO THE EVENING. THE NAM HAS HIGHER LOW
LEVEL RH STICKING AROUND THROUGH THE NIGHT...SO WILL HAVE TO
CONSIDER KEEPING LOWER CIGS AROUND LATER. WILL HAVE TO EVALUATE
CLOSELY LOOK AT CIGS FOR TOMORROW AS WELL. CURRENTLY HAVE SCATTERED
CLOUDS IN THE FORECAST...BUT THE NAM WANTS TO KEEP THE LOW CLOUDS
GOING RIGHT THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 252 AM CST FRI FEB 10 2012/
VERY SHORT TERM...TODAY AND TONIGHT.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE KENOSHA AREA AROUND NOON.
A MID LEVEL SHORTWAVE WILL DROP SOUTHEAST AND EXTEND ACROSS EASTERN
LAKE SUPERIOR TO FAR SOUTHERN MINNESOTA BY NOON AND PUSH ACROSS
SOUTHEAST WISCONSIN EARLY THIS AFTERNOON. THIS IS SLOWING THE
SOUTHWARD PROGRESSION OF THE FRONT AND ALSO CAUSING WEAK UPWARD
MOTION TO CONTINUE AFTER THE FRONTAL PASSAGE. FORECAST SOUNDINGS
SHOW MOISTURE EXTENDING FROM THE LOW LEVELS THROUGHOUT THE MID
LEVELS. MID LEVELS THEN DRY BEHIND THE 500 MB TROUGH AXIS. AS THIS
HAPPENS LOW LEVEL LAPSE RATES INCREASE TO ALMOST 9 C/KM FROM THE
SURFACE TO 850 MB. THEREFORE EXPECT AN INITIAL SNOW SHOWER
POTENTIAL WITH THE FRONT...BUT SOME LIGHT SNOW SHOWERS/FLURRIES WILL
CONTINUE ACROSS SOUTH CENTRAL WISCONSIN THIS AFTERNOON AND ACROSS
SOUTHEAST WISCONSIN INTO THE EARLY EVENING.
NEXT PROBLEM IS INITIAL LAKE ENHANCEMENT BEHIND THE FRONT. NAM
FORECAST SOUNDINGS GENERATE LAKE ENHANCEMENT WITH AROUND 200 J/KG
OF CAPE EARLY THIS AFTERNOON AND AROUND 300 J/KG LATE THIS AFTERNOON
AND 400 J/KG EARLY THIS EVENING. DELTA T VALUES ARE MARGINAL THIS
AFTERNOON BUT JUMP TO MODERATE THIS EVENING OF -17 C. NAM SOUNDING
INDICATE THAT BY THE TIME THIS HAPPENS WINDS BECOME NORTH ACROSS
MUCH OF THE LOW LEVELS EXCEPT NORTHEAST IN A NARROW LAYER AROUND 4
THSD FT. RUC SOUNDINGS ARE MORE FAVORABLE WITH NNE OR NE WINDS FROM
JUST ABOVE THE SURFACE TO ALMOST 7 THSD FT.
WILL HOLD OFF ON ANY HEADLINES DUE TO THE UNCERTAINTY...BUT WILL
BUMP UP THE SNOW AMOUNTS NEAR THE LAKE.
AFTER MIDNIGHT THE 500 MB TROUGH REACHES LOWER MICHIGAN...AND THE
SOUNDINGS NEAR LAKE MICHIGAN SHOW A PRONOUNCED DRYING ABOVE
3 THSD FT.
SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT.
SPRAWLING...SLOW MOVING HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS
TONIGHT AND SATURDAY AS COLD AIR SETTLES OVER THE REGION. CORE OF
COLDEST AIR WITH 85H TEMPS AROUND -18C SHIFTS SLOWLY EWD ON
SAT...CONTINUING ON SUN AS THE LOW LEVEL WINDS BEGIN TO BACK MORE
NORTHWEST. NEVERTHELESS...DESPITE SUNSHINE DO NOT WANT TO WARM TEMPS
TOO FAST AS BLUSTERY NORTHWEST WINDS WL CONTINUE ON SAT AT THE
SFC...AND SOME AREAS WL LIKELY HAVE A FRESH LIGHT SNOW COVER. MAY BE
ABLE TO MIX TO AROUND 925H BOTH DAYS. HENCE DESPITE COLD BIAS DUE
TO PERSISTENT LACK OF SNOW...WL KEEP HIGHS IN THE 15 TO 20 RANGE
MOST AREAS SAT...AND IN MID-UPR 20S SUN. BLUSTERY NORTHWEST WINDS
OF 15 TO 25KTS WL ADD A STRONG CHILL TO THE AIR ON SAT. WIND CHILLS
WILL DROP TO BTWN 5 AND 15 BLO ZERO EARLY SAT MRNG AND AGAIN LATE
SAT NGT/EARLY SUN MRNG.
PERIOD OF MID-HIGH LEVEL CLOUDS ASSOCD WITH SURGE OF WARM AIR
ADVECTION MAY BRUSH PORTIONS OF SRN WI SAT NGT...BUT MAJORITY OF
CLOUDS REMAIN NORTH.
LONG TERM...MONDAY THROUGH THURSDAY.
EXTENDED GUIDANCE REMAINS IN REASONABLE AGREEMENT THROUGH EARLY
PERIODS. INCREASING SOUTHERLY WINDS ON THE BACKSIDE OF THE LARGE
HIGH PRESSURE AREA ALLOW MOISTURE TO INCREASE TO AROUND 0.4 INCH BY
LATER MONDAY. STRONGEST TEMP/MOISTURE ADVECTION HOWEVER REMAINS TO
THE SOUTH OF WI...HOWEVER ECMWF...GFS AND GEM-NHEM DO INCREASE
MOISTURE TO AT LEAST 10K FEET. ALTHOUGH FORCING REMAINS WEAK AS MID
LEVEL SHORT WAVE MOVES THROUGH MONDAY NIGHT...CONDENSATION PRESSURE
DEFICITS DECREASE TO LESS THAN 10MB ON MONDAY WITH WEAK ISENTROPIC
OMEGA. WITH SLR AROUND 15 TO 1...POSSIBLE FOR AN INCH OR TWO OF
SNOW MONDAY INTO MONDAY NIGHT. ENOUGH CONSISTENCY AND AGREEMENT TO
BUMP UP POPS TO LIKELY OVER MORE OF SRN WI MON AFTN CLOSER TO
STRONGER LOW LEVEL WEAK FORECING...AND IN THE SOUTHEAST MON NGT.
MID LEVEL WEAK WAVE STILL EXPECTED TO SLIDE OFF TO THE EAST BY
TUESDAY... HOWEVER PROGRESS HAS SLOWED A BIT AS SECONDARY WEAK WAVE
MOVES FROM THE UPPER MIDWEST INTO THE CENTRAL MS VALLEY. WL
CONTINUE DRYING TREND INTO TUE...BUT KEEP SCHC POPS IN THE FAR
SOUTHEAST TO REFLECT SLOWER MOVEMENT.
SEVERAL DAYS AGO...THOUGHT WE WERE HEADING TO A MORE UNSETTLED
PERIOD FOR LATER NEXT WEEK...AS MULTIPLE PIECES OF SHORT WAVE ENERGY
WERE EJECTED FROM PERSISTENT NRN PACIFIC LONG WAVE TROUGH INTO
CENTRAL CONUS. HOWEVER LAST DAY OR TWO...TREND HAS BEEN TOWARD
RETURN OF SPLIT FLOW ACROSS CONUS...WITH SRN STREAM REMAINING MORE
ACTIVE FROM TUE INTO THU. ECWMF FIRST TO PICK UP ON DRIER NRN
STREAM SIGNAL...AND LAST SEVERAL RUNS OF GFS NOW BACKING OFF ON
UNSETTLED MID-WEEK WX FOR UPPER MIDWEST. HPC ALSO TRENDING TOWARD
DRIER SOLUTION...FAVORING ECMWF OR ECMWF BLEND. FOR NOW...WL KEEP
POPS VERY LOW FOR LATE PDS WITH LOW CONFIDENCE. END RESULT...PALTRY
WINTER CONDITIONS TO CONTINUE.
AVIATION /12Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE BROUGHT MVFR STRATUS
ACROSS THE FORECAST AREA AND WILL PERSIST EARLY THIS MORNING.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE FAR SOUTHEAST TIP AROUND NOON. MAINLY CIGS
EXPECTED BEHIND THE FRONT ALONG WITH MVFR VSBYS IN SNOW SHOWERS WITH
SOME IFR VSBYS IN THE HEAVIER SNOW SHOWERS. APPEARS LAKE
ENHANCEMENT TO DEVELOP LATE THIS MORNING TOWARD SHEBOYGAN AND
ACROSS SOUTHEAST WISCONSIN FROM MILWAUKEE SOUTH THIS AFTERNOON.
OCCASIONAL IFR VSBYS EXPECTED WITH THIS SNOW. BY EVENING A LAKE
EFFECT SNOW BAND SHOULD SET UP MAINLY OVER WESTERN LAKE MICHIGAN AND
AFFECT AREAS MAINLY SOUTH OF THE ILLINOIS BORDER...BUT THERE IS A
POSSIBILITY OF SOME OF THIS SNOW AFFECTING THE SHORELINE AREAS
MAINLY SOUTH OF MILWAUKEE.
MARINE...
WINDS MAY BRIEFLY DROP BELOW SMALL CRAFT CRITERIA EARLY THIS MORNING
JUST AHEAD OF A TROUGH OF LOW PRESSURE EXTENDING ACROSS NORTHERN
LAKE MICHIGAN. AS AN ASSOCIATED STRONG COLD FRONT DROPS SOUTH
ACROSS SOUTHERN LAKE MICHIGAN LATER THIS MORNING WINDS WILL BECOME
NORTH AND INCREASE DRAMATICALLY. A FEW WIND GUSTS MAY APPROACH GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS.
DUE TO THE COLDER AIR WAVES EXPECTED TO INCREASE RAPIDLY BEHIND THE
FRONT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL OF THE SHORE
AREAS INTO SATURDAY AFTERNOON.
CONFIDENCE...
TODAY AND TONIGHT...MEDIUM.
SATURDAY THROUGH SUNDAY NIGHT...MEDIUM TO HIGH.
MONDAY AND MONDAY NIGHT...MEDIUM TO HIGH.
TUESDAY...MEDIUM.
WEDNESDAY AND THURSDAY...LOW TO MEDIUM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CST SATURDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
UPDATE...GEHRING/DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SATURDAY THROUGH THURSDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
237 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUDS/TEMPERATURES/PRECIPITATION
TODAY...THEN WIND CHILLS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S INTO THE NORTHWEST
TERRITORIES OF CANADA...AND TROUGHING FROM THE DAKOTAS INTO QUEBEC.
WITHIN THIS TROUGH...A SHORTWAVE WAS PRESENT FROM NORTH DAKOTA INTO
NORTHERN MINNESOTA. A REMNANT STREAM OF PACIFIC MOISTURE AND DPVA
AHEAD OF THE SHORTWAVE HELPING TO PRODUCE A BAND OF MID-CLOUDS FROM
NORTHEAST SOUTH DAKOTA TO LAKE SUPERIOR. BELOW THIS...AN AREA OF
STRATUS RESULTING FROM MOISTURE TRAPPED IN A COLD FRONTAL INVERSION
WAS PRESENT FROM NORTHWEST IOWA INTO NORTHERN WISCONSIN. SOME LIGHT
SNOW WAS ALSO FALLING OUT OF THIS STRATUS OVER THE NORTH HALF OF
WISCONSIN...DUE TO THE PRESENCE OF LOW LEVEL FRONTOGENESIS PER RUC
ANALYSIS. THE THERMAL CONTRAST OF THE FRONTOGENESIS COULD BE SEEN
FROM A 00Z 850MB SOUNDING PLOT...NOTED BY A -6C TEMP AT MPX AND -17C
AT INL. AT THE SURFACE...A COLD FRONTAL BOUNDARY STRETCHED FROM
NORTHERN LAKE MICHIGAN SOUTHWEST TO DES MOINES...WHILE A 1041MB
ARCTIC HIGH PRESSURE AREA WAS OVER CENTRAL SASKATCHEWAN.
TODAY AND TONIGHT...SHORTWAVE OVER NORTH DAKOTA AND NORTHERN
MINNESOTA IS PROGGED TO MOVE THROUGH THE FORECAST AREA BETWEEN
15-21Z TODAY...ALLOWING THE ARCTIC HIGH PRESSURE AREA OVER
SASKATCHEWAN TO DROP SOUTH IN ITS WAKE. BY 12Z SATURDAY...THE HIGH
SHOULD BE SITUATED IN THE DAKOTAS. WITH THE HIGH WELL OFF TO THE
WEST...ANTICIPATING BLUSTERY CONDITIONS ACROSS MUCH OF THE FORECAST
AREA THROUGH TONIGHT. WIND DIRECTION IS A LITTLE INTERESTING. DUE TO
THE TRACK OF THE DEPARTING COLD FRONT...THE SURFACE-850MB WINDS ARE
MORE NORTH TO NORTHEAST TODAY...THEN SWITCHES TO THE NORTHWEST
TONIGHT. THIS WIND DIRECTION PATTERN MEANS THAT LOW LEVEL MOISTURE/
CLOUDS MAY GET STUCK OVER THE FORECAST AREA MORE TODAY...AIDED BY
MOISTENING OFF LAKE SUPERIOR. ONCE THE WINDS GO NORTHWEST...THE DRY
ARCTIC AIR CAN FLOW IN AND CLEAR OUT THE STRATUS. ONE CAVEAT IS THAT
RIGHT NOW THE AIR OVER NORTHERN ONTARIO IS DRIER THAN THE MODELS
SUGGEST. WILL HAVE TO WATCH TO SEE THROUGH THE DAY TODAY ON HOW MUCH
OF THIS DRIER AIR OVER NORTHERN ONTARIO ADVECTS SOUTH. NEXT CONCERN
IS THE PRECIPITATION. THE 10.00Z NAM AND HRRR RUNS HAVE SHOWN SOME
VERY LIGHT SNOW/FLURRIES...MOSTLY ALONG AND EAST OF THE MISSISSIPPI
RIVER THIS MORNING. LOW LEVEL FRONTOGENETICAL FORCING APPEARS TO BE
THE MAIN PRODUCTION FEATURE...WITH THE SNOW MORE LIKELY TO OCCUR DUE
TO THE STRATUS EVENTUALLY INTERSECTING THE DENDRITIC GROWTH ZONE AS
THE COLDER AIR MOVES IN. A FEW TENTHS SEEM POSSIBLE. HAVE LEFT SOME
FLURRIES IN FOR THE AFTERNOON TOO...BUT THINK THE BULK OF ANY
ACCUMULATING TYPE SNOW WOULD BE OFF TO THE EAST WHERE THE LOW LEVEL
FRONTOGENESIS IS EXPECTED. FINAL CONCERN IS TEMPERATURES. 850MB
TEMPS REALLY DROP TODAY...FROM -8C SOUTHEAST TO -16C NORTHWEST
ACROSS THE FORECAST AREA AT 12Z...TO BASICALLY AROUND -20C AT 00Z.
WITH STRATUS IN PLACE AND FALLING 850MB TEMPS...LOOK FOR SURFACE
TEMPERATURES TO SLOWLY FALL THROUGH THE DAY...DROPPING WIND CHILLS.
TONIGHT...THE TEMPERATURE FALL WILL MAINLY BE A RESULT OF ADVECTION
DUE TO BLUSTERY CONDITIONS KEEPING THE BOUNDARY LAYER MIXED.
STILL...LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO SUGGESTED BY
GUIDANCE AND THE PREVIOUS FORECAST SEEM REASONABLE. MAY NEED WIND
CHILL ADVISORIES FOR PORTIONS OF THE AREA VERY LATE...MOST LIKELY
TAYLOR AND CLARK ZONES. GIVEN SUCH A SMALL AREA AND MARGINAL WIND
CHILLS AT THAT...HELD OFF ON ISSUING AN ADVISORY AT THIS TIME.
SATURDAY THROUGH SUNDAY NIGHT...FAIRLY QUIET PERIOD EXPECTED AS
500MB HEIGHTS GRADUALLY BUILD. ARCTIC HIGH PRESSURE AREA NEVER
BUILDS OVER THE AREA...TRACKING MORE SOUTH TO THE LOWER MISSISSIPPI
RIVER VALLEY BY MID-DAY SUNDAY. THIS TRACK SHOULD KEEP CONDITIONS
FROM DECOUPLING SATURDAY NIGHT...PREVENTING ANY DRAMATIC TEMPERATURE
FALL FROM RADIATIONAL COOLING. ONLY REAL CONCERN IS SUNDAY NIGHT.
DURING THIS PERIOD...MODELS HAVE UPPER TROUGHING CROSSING THE
WESTERN U.S. TOWARDS THE PLAINS WITH RIDGING BUILDING UP TOWARDS THE
FORECAST AREA. 10.00Z NAM HINTS THAT A FEW WEAK SHORTWAVES MAY COME
OUT OF THE TROUGH AND APPROACH THE AREA BY 12Z MONDAY. WITH THESE
SHORTWAVES...THE NAM BRINGS SOME PRECIPITATION INTO NORTHEAST IOWA
AFTER MIDNIGHT SUNDAY NIGHT. BY FAR THE NAM IS THE FASTEST OF ANY
GUIDANCE AND THEREFORE FOR NOW HAS BEEN DISCOUNTED. HAVE DRIED OUT
ALMOST ALL OF THE FORECAST AREA AS A RESULT...THOUGH LEFT A 20
PERCENT CHANCE FOR CHARLES CITY TO OELWEIN IA JUST IN CASE THE
FASTER SCENARIO WOULD PLAY OUT. AN INCREASE IN MID TO UPPER LEVEL
CLOUD COVER IS LIKELY SUNDAY NIGHT...HOWEVER. A GRADUAL WARMING
TREND IS ANTICIPATED THROUGH THE WEEKEND AS THE ARCTIC HIGH SLOWLY
MODIFIES...HELPED TOO BY THE GENERAL LACK OF SNOW COVER FROM THE
DAKOTAS INTO THE UPPER MISSISSIPPI RIVER VALLEY. 850MB TEMPS CLIMB
TO -12C BY 00Z SUNDAY AND -6C BY 00Z MONDAY. WITH THE WARMING 850MB
TEMPS...HIGHS SHOULD CLIMB INTO THE 15 TO 20F RANGE ON SATURDAY AND
25 TO 30F RANGE ON SUNDAY.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
237 AM CST FRI FEB 10 2012
OVERALL PATTERN LOOKS FAIRLY BENIGN THROUGHOUT MUCH OF THE LONG TERM
PERIOD SUGGESTED BY THE 10.00Z ECMWF/CANADIAN/GFS/UKMET AND GFS
ENSEMBLES. A SPLIT FLOW SCENARIO IS FORECAST BY ALL OF THESE
MODELS...WITH THE NORTHERN STREAM FEATURING ZONAL TO WEAK TROUGHING
ACROSS SOUTHERN CANADA...AND A SOUTHERN STREAM FEATURING TROUGHING
IN THE SOUTHWEST U.S. TO ZONAL TO SLIGHT RIDGING OVER THE
SOUTHEASTERN U.S.. THIS MEANS MOST OF THE PRECIPITATION ACTION ENDS
UP STAYING TO THE NORTH AND SOUTH OF THE FORECAST AREA WITH NO COLD
SHOTS IN THE OFFERING. THE ONLY EXCEPTION TO THE PRECIPITATION IS
MONDAY INTO MONDAY EVENING...DUE TO THE COMBINATION OF WEAK LOW
LEVEL MOISTURE TRANSPORT AND WEAK SHORTWAVES PROGGED TO MOVE THROUGH
THE AREA. THESE SHORTWAVES ORIGINATING OUT OF THE TROUGHING MOVING
INTO THE PLAINS SUNDAY NIGHT. THERE REMAINS STRONG CONTINUITY FOR
PRECIPITATION SOUTH OF I-90...SO MAINTAINED 50-60 PERCENT CHANCES
THERE FOR MONDAY. PRECIPITATION CHANCES TAPER OFF HEADING NORTH AS
CONFIDENCE IN MOISTURE AVAILABILITY IS LOWER. DOES NOT LOOK LIKE
ANYTHING BIG IN TERMS OF SNOW ACCUMULATION GIVEN THE WEAK
FORCING...PERHAPS AROUND AN INCH. A LITTLE FARTHER OUT...THE 10.00Z
ECMWF/CANADIAN BOTH HINT AT SOME SHORTWAVE TROUGHS CROSSING THE AREA
WEDNESDAY NIGHT INTO THURSDAY...ORIGINATING FROM SOUTHERN EXTENSIONS
OFF THE NORTHERN STREAM. WITH LACK OF MOISTURE...KEPT THE CONSENSUS
15 TO 20 PERCENT CHANCES. WOULD NOT BE SURPRISED IF IT ENDS UP DRY.
TEMPERATURES THROUGHOUT THE LONG TERM PERIOD SHOULD END UP AT OR
ABOVE NORMAL DUE TO ALL THE COLD AIR BEING LOCKED BACK UP OVER
NORTHERN CANADA. IN FACT...IT APPEARS THE GENERAL ABOVE NORMAL
CONDITIONS WILL PERSIST AT LEAST FOR THE NEXT ONE TO TWO WEEKS...IF
NOT LONGER...PER THE CFS VERSION 2 FORECASTS.
&&
.AVIATION...THROUGH 18Z SATURDAY
1130 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUD HEIGHTS THIS AFTERNOON AND THEN
CLEARING TREND LATER TODAY. MVFR-VFR CEILINGS GENERALLY IN THE
025KFT-040KFT RANGE EXTEND ACROSS THE REGION LATE THIS MORNING AS
SHORTWAVE TROUGH IS DROPPING ACROSS THE REGION. MODELS ARE SHOWING
CEILINGS WILL REMAIN IN THE VFR CATEGORY THROUGH MUCH OF THE
AFTERNOON. THERE STILL COULD BE A FEW FLURRIES THROUGHOUT THE
AFTERNOON...BUT BETTER CHANCES WILL BE SOUTH OF THE TAF SITES AND
THUS WILL NOT INCLUDE IN THE 18Z TAFS. SOME BREAKS BEING SEEN IN
THE CLOUDS ACROSS NORTHERN WISCONSIN...AND WOULD EXPECT CEILINGS
TO BECOME BROKEN LATER THIS AFTERNOON BETWEEN 21Z-23Z....WITH
CLEAR SKIES AND VFR CONDITIONS THEN AFTER 01Z-02Z AND CONTINUING
THROUGH 18Z SATURDAY. NORTH WINDS WILL ALSO GUST TO 20 TO 25 KNOTS
MUCH OF THE AFTERNOON...WITH THE GUSTS DIMINISHING THIS
EVENING... THEN PICKING UP AGAIN AFTER 15Z SATURDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 AM CST FRI FEB 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING