Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/09/12
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1207 PM MST TUE FEB 7 2012
.UPDATE...
HAVE ADJUSTED GRIDS/ZONES TO ACCOUNT FOR LINGERING CLOUDS/ISOLATED
SNOW SHOWERS OVER EASTERN SECTIONS OF THE FORECAST DISTRICT.
&&
.PREV DISCUSSION... /ISSUED 1053 AM MST TUE FEB 7 2012/
AVIATION...
ISOLATED GENERALLY LIGHT SNOW SHOWERS ARE EXPECTED TO CONTINUE
THROUGH LATE THIS MORNING WITH VFR CONDITIONS THEN EXPECTED TO
RETURN TO THE KALS...KCOS AND KPUB TAF SITES AFT 22Z TODAY.
PREV DISCUSSION... /ISSUED 437 AM MST TUE FEB 7 2012/
SHORT TERM...
(TODAY AND TONIGHT)
.COLD WEATHER THROUGH TONIGHT....
CURRENTLY...SOME LIGHT SHSN OVR OTERO AND SRN PUEBLO COUNTIES.
COULD SEE SOME MINOR ACCUMS THIS MORNING S OF HWY 50...ESPECIALLY
OVR THE RATON MESA. MODELS HAVE NOT HANDLED THIS PRECIP VERY
WELL...BUT THE RUC HAS THE SNOW PRETTY WELL DEPICTED...AND IT MOVES
MOST OF THE PRECIP OUT OF OUR AREA BY 15Z. THIS LOOKS REASONABLE
WITH THE UPPER LOW CONTINUING TO TRANSLATE INTO NE AND NW KS.
MAIN STORY TODAY WILL BE THE COLD. TEMPS HAVE NOT FALLEN MUCH OVR
THE PLAINS THIS MORN...AS OF 3 AM IT IS STILL IN THE UPPR 20 FOR
MANY SPOTS...THANKS TO THE PRECIP...LOW CLOUDS...AND WIND.
HOWEVER...WITH H7 TEMPS NOW BOTTOMING OUT IN THE MINUS 13 TO 14
RANGE...WILL NOT SEE MUCH WARMING TODAY DESPITE CLEARING SKIES THIS
AFTERNOON. A FEW SPOTS COULD RISE ABOVE FREEZING BUT OTHERWISE IT
WILL STAY IN THE UPPER 20S FOR MUCH OF THE DAY. A STRONG SURFACE
HIGH OVR THE DAKOTAS WILL CONTINUE TO SLIDE SWD THROUGH THIS
EVENING...AND THIS WILL KEEP LIGHT UPSLOPE WINDS OVER SE CO THRU
TONIGHT. DESPITE RISING TEMPS ALOFT...AS A WEAK RIDGE BUILDS BRIEFLY
OVR THE AREA...EXPECT A STRONGLY DECOUPLED BL TONIGHT...WITH TEMPS
NEARING OR DROPPING BELOW ZERO FOR SOME OF THE HIGH VALLEY COLD
SPOTS. COULD ALSO SEE TEMPS NR ZERO OVER THE LOWER ARKANSAS WITH
CLEARING SKIES AND LIGHT WINDS TONIGHT. POPS WILL REMAIN NR ZERO
THRU WED MORNING. SOME HIGH CLOUDS WILL BEGIN MOVING INTO THE SW MTS
BY SUNRISE WED...AS THE NEXT SHORT WAVE TROUGH APPROACHES FROM THE
W. 44
LONG TERM...
(WEDNESDAY THROUGH MONDAY)
SLOW WARMING TREND BEGINS WEDNESDAY AHEAD OF WEAK UPPER TROUGH
SHEARING SOUTH THROUGH THE GREAT BASIN. EXPECT A FEW -SHSN TO
DEVELOP ALONG THE CONTINENTAL DIVIDE WED AFTERNOON...PERSISTING
THROUGH THE DAY THU AS SYSTEM SLOWLY DROPS SOUTH. DYNAMICS LOOK
WEAK AND MOISTURE IS LIMITED...SO NOT EXPECTING MORE THAN SCATTERED
SNOW SHOWERS WITH THE SYSTEM AT THIS POINT. MODELS HINT AT A FEW
SHOWERS OVER THE SANGRES THU MORNING...SO WILL KEEP SOME ISOLATED
POPS IN PLACE SOUTH OF LA VETA PASS. MAX TEMPS WED SHOULD WARM
10-15F VERSUS TODAY`S (TUE) NUMBERS...THEN ADD ANOTHER 3-5F THU AS
BETTER MIXING WILL LIKELY OFFSET MINOR COLD ADVECTION. FRI-SAT
LOOK MAINLY DRY AND SEASONABLE...AS WESTERN EDGE OF ARCTIC AIR
MASS OVER THE CENTRAL PLAINS STAYS EAST OF THE KS BORDER. NEW
WESTERN TROUGH TAKES SHAPE SUN...THOUGH DETAILS VARY AS 06Z GFS
TAKES SYSTEM FARTHER SOUTH AND HAS LESS IMPACT THAN RATHER SNOWY
00Z RUN. IN GENERAL...EXTENDED PROCEDURE GRIDS BEGIN A GRADUAL
TREND TOWARD COLDER/WETTER WEATHER SUN/MON...THOUGH IF TRENDS
CONTINUE...MAY NEED TO RAISE POPS/LOWER TEMPS MORE SUBSTANTIALLY IN
SUBSEQUENT FORECASTS. --10
AVIATION...ISOLD LIGHT SHSN WILL PERSIST THROUGH THIS
MORNING...ENDING BY 13-15Z FOR AREAS VC KCOS AND KALS. AT THE
SAME TOME...N WINDS AT KCOS AND KPUB SHOULD RELAX BY MID
MORNING...AND WILL REMAIN LIGHT AND FROM THE E TO SE THROUGH TODAY
AND INTO TONIGHT. 44
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1053 AM MST TUE FEB 7 2012
&&
.AVIATION...
ISOLATED GENERALLY LIGHT SNOW SHOWERS ARE EXPECTED TO CONTINUE
THROUGH LATE THIS MORNING WITH VFR CONDITIONS THEN EXPECTED TO
RETURN TO THE KALS...KCOS AND KPUB TAF SITES AFT 22Z TODAY.
&&
.PREV DISCUSSION... /ISSUED 437 AM MST TUE FEB 7 2012/
SHORT TERM...
(TODAY AND TONIGHT)
..COLD WEATHER THROUGH TONIGHT....
CURRENTLY...SOME LIGHT SHSN OVR OTERO AND SRN PUEBLO COUNTIES.
COULD SEE SOME MINOR ACCUMS THIS MORNING S OF HWY 50...ESPECIALLY
OVR THE RATON MESA. MODELS HAVE NOT HANDLED THIS PRECIP VERY
WELL...BUT THE RUC HAS THE SNOW PRETTY WELL DEPICTED...AND IT MOVES
MOST OF THE PRECIP OUT OF OUR AREA BY 15Z. THIS LOOKS REASONABLE
WITH THE UPPER LOW CONTINUING TO TRANSLATE INTO NE AND NW KS.
MAIN STORY TODAY WILL BE THE COLD. TEMPS HAVE NOT FALLEN MUCH OVR
THE PLAINS THIS MORN...AS OF 3 AM IT IS STILL IN THE UPPR 20 FOR
MANY SPOTS...THANKS TO THE PRECIP...LOW CLOUDS...AND WIND.
HOWEVER...WITH H7 TEMPS NOW BOTTOMING OUT IN THE MINUS 13 TO 14
RANGE...WILL NOT SEE MUCH WARMING TODAY DESPITE CLEARING SKIES THIS
AFTERNOON. A FEW SPOTS COULD RISE ABOVE FREEZING BUT OTHERWISE IT
WILL STAY IN THE UPPER 20S FOR MUCH OF THE DAY. A STRONG SURFACE
HIGH OVR THE DAKOTAS WILL CONTINUE TO SLIDE SWD THROUGH THIS
EVENING...AND THIS WILL KEEP LIGHT UPSLOPE WINDS OVER SE CO THRU
TONIGHT. DESPITE RISING TEMPS ALOFT...AS A WEAK RIDGE BUILDS BRIEFLY
OVR THE AREA...EXPECT A STRONGLY DECOUPLED BL TONIGHT...WITH TEMPS
NEARING OR DROPPING BELOW ZERO FOR SOME OF THE HIGH VALLEY COLD
SPOTS. COULD ALSO SEE TEMPS NR ZERO OVER THE LOWER ARKANSAS WITH
CLEARING SKIES AND LIGHT WINDS TONIGHT. POPS WILL REMAIN NR ZERO
THRU WED MORNING. SOME HIGH CLOUDS WILL BEGIN MOVING INTO THE SW MTS
BY SUNRISE WED...AS THE NEXT SHORT WAVE TROUGH APPROACHES FROM THE
W. 44
LONG TERM...
(WEDNESDAY THROUGH MONDAY)
SLOW WARMING TREND BEGINS WEDNESDAY AHEAD OF WEAK UPPER TROUGH
SHEARING SOUTH THROUGH THE GREAT BASIN. EXPECT A FEW -SHSN TO
DEVELOP ALONG THE CONTINENTAL DIVIDE WED AFTERNOON...PERSISTING
THROUGH THE DAY THU AS SYSTEM SLOWLY DROPS SOUTH. DYNAMICS LOOK
WEAK AND MOISTURE IS LIMITED...SO NOT EXPECTING MORE THAN SCATTERED
SNOW SHOWERS WITH THE SYSTEM AT THIS POINT. MODELS HINT AT A FEW
SHOWERS OVER THE SANGRES THU MORNING...SO WILL KEEP SOME ISOLATED
POPS IN PLACE SOUTH OF LA VETA PASS. MAX TEMPS WED SHOULD WARM
10-15F VERSUS TODAY`S (TUE) NUMBERS...THEN ADD ANOTHER 3-5F THU AS
BETTER MIXING WILL LIKELY OFFSET MINOR COLD ADVECTION. FRI-SAT
LOOK MAINLY DRY AND SEASONABLE...AS WESTERN EDGE OF ARCTIC AIR
MASS OVER THE CENTRAL PLAINS STAYS EAST OF THE KS BORDER. NEW
WESTERN TROUGH TAKES SHAPE SUN...THOUGH DETAILS VARY AS 06Z GFS
TAKES SYSTEM FARTHER SOUTH AND HAS LESS IMPACT THAN RATHER SNOWY
00Z RUN. IN GENERAL...EXTENDED PROCEDURE GRIDS BEGIN A GRADUAL
TREND TOWARD COLDER/WETTER WEATHER SUN/MON...THOUGH IF TRENDS
CONTINUE...MAY NEED TO RAISE POPS/LOWER TEMPS MORE SUBSTANTIALLY IN
SUBSEQUENT FORECASTS. --10
AVIATION...ISOLD LIGHT SHSN WILL PERSIST THROUGH THIS
MORNING...ENDING BY 13-15Z FOR AREAS VC KCOS AND KALS. AT THE
SAME TOME...N WINDS AT KCOS AND KPUB SHOULD RELAX BY MID
MORNING...AND WILL REMAIN LIGHT AND FROM THE E TO SE THROUGH TODAY
AND INTO TONIGHT. 44
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
437 AM MST TUE FEB 7 2012
.SHORT TERM...
(TODAY AND TONIGHT)
...COLD WEATHER THROUGH TONIGHT....
CURRENTLY...SOME LIGHT SHSN OVR OTERO AND SRN PUEBLO COUNTIES.
COULD SEE SOME MINOR ACCUMS THIS MORNING S OF HWY 50...ESPECIALLY
OVR THE RATON MESA. MODELS HAVE NOT HANDLED THIS PRECIP VERY
WELL...BUT THE RUC HAS THE SNOW PRETTY WELL DEPICTED...AND IT MOVES
MOST OF THE PRECIP OUT OF OUR AREA BY 15Z. THIS LOOKS REASONABLE
WITH THE UPPER LOW CONTINUING TO TRANSLATE INTO NE AND NW KS.
MAIN STORY TODAY WILL BE THE COLD. TEMPS HAVE NOT FALLEN MUCH OVR
THE PLAINS THIS MORN...AS OF 3 AM IT IS STILL IN THE UPPR 20 FOR
MANY SPOTS...THANKS TO THE PRECIP...LOW CLOUDS...AND WIND.
HOWEVER...WITH H7 TEMPS NOW BOTTOMING OUT IN THE MINUS 13 TO 14
RANGE...WILL NOT SEE MUCH WARMING TODAY DESPITE CLEARING SKIES THIS
AFTERNOON. A FEW SPOTS COULD RISE ABOVE FREEZING BUT OTHERWISE IT
WILL STAY IN THE UPPER 20S FOR MUCH OF THE DAY. A STRONG SURFACE
HIGH OVR THE DAKOTAS WILL CONTINUE TO SLIDE SWD THROUGH THIS
EVENING...AND THIS WILL KEEP LIGHT UPSLOPE WINDS OVER SE CO THRU
TONIGHT. DESPITE RISING TEMPS ALOFT...AS A WEAK RIDGE BUILDS BRIEFLY
OVR THE AREA...EXPECT A STRONGLY DECOUPLED BL TONIGHT...WITH TEMPS
NEARING OR DROPPING BELOW ZERO FOR SOME OF THE HIGH VALLEY COLD
SPOTS. COULD ALSO SEE TEMPS NR ZERO OVER THE LOWER ARKANSAS WITH
CLEARING SKIES AND LIGHT WINDS TONIGHT. POPS WILL REMAIN NR ZERO
THRU WED MORNING. SOME HIGH CLOUDS WILL BEGIN MOVING INTO THE SW MTS
BY SUNRISE WED...AS THE NEXT SHORT WAVE TROUGH APPROACHES FROM THE
W. ROSE
.LONG TERM...
(WEDNESDAY THROUGH MONDAY)
SLOW WARMING TREND BEGINS WEDNESDAY AHEAD OF WEAK UPPER TROUGH
SHEARING SOUTH THROUGH THE GREAT BASIN. EXPECT A FEW -SHSN TO
DEVELOP ALONG THE CONTINENTAL DIVIDE WED AFTERNOON...PERSISTING
THROUGH THE DAY THU AS SYSTEM SLOWLY DROPS SOUTH. DYNAMICS LOOK
WEAK AND MOISTURE IS LIMITED...SO NOT EXPECTING MORE THAN SCATTERED
SNOW SHOWERS WITH THE SYSTEM AT THIS POINT. MODELS HINT AT A FEW
SHOWERS OVER THE SANGRES THU MORNING...SO WILL KEEP SOME ISOLATED
POPS IN PLACE SOUTH OF LA VETA PASS. MAX TEMPS WED SHOULD WARM
10-15F VERSUS TODAY`S (TUE) NUMBERS...THEN ADD ANOTHER 3-5F THU AS
BETTER MIXING WILL LIKELY OFFSET MINOR COLD ADVECTION. FRI-SAT
LOOK MAINLY DRY AND SEASONABLE...AS WESTERN EDGE OF ARCTIC AIR
MASS OVER THE CENTRAL PLAINS STAYS EAST OF THE KS BORDER. NEW
WESTERN TROUGH TAKES SHAPE SUN...THOUGH DETAILS VARY AS 06Z GFS
TAKES SYSTEM FARTHER SOUTH AND HAS LESS IMPACT THAN RATHER SNOWY
00Z RUN. IN GENERAL...EXTENDED PROCEDURE GRIDS BEGIN A GRADUAL
TREND TOWARD COLDER/WETTER WEATHER SUN/MON...THOUGH IF TRENDS
CONTINUE...MAY NEED TO RAISE POPS/LOWER TEMPS MORE SUBSTANTIALLY IN
SUBSEQUENT FORECASTS. --PETERSEN
&&
.AVIATION...ISOLD LIGHT SHSN WILL PERSIST THROUGH THIS
MORNING...ENDING BY 13-15Z FOR AREAS VC KCOS AND KALS. AT THE
SAME TOME...N WINDS AT KCOS AND KPUB SHOULD RELAX BY MID
MORNING...AND WILL REMAIN LIGHT AND FROM THE E TO SE THROUGH TODAY
AND INTO TONIGHT. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
44/10
PREVIOUS FORECAST DISCUSSION IS BELOW...
AS OF 300 PM EST...SUNNY SKIES AND MILD TEMPS PREVAILED ACROSS
THE FA WITH TEMPS RANGING FROM AROUND 40 NORTHWEST TO THE LOWER
50S SOUTHEAST.
FOR TONIGHT AND TUESDAY...EXPECT A COLD FRONT TO DROP SOUTHEAST FROM
THE SAINT LAWRENCE VALLEY THIS EVENING THROUGH OUR REGION LATE
TONIGHT INTO TUESDAY MORNING AND BE LOCATED ACROSS FAR SOUTHEAST NEW
YORK AND THE SOUTHERN NEW ENGLAND COAST EARLY TUESDAY AFTERNOON.
THERE IS VERY LITTLE MOISTURE ASSOCIATED WITH THIS SYSTEM AND OTHER
THAN AN INCREASE IN CLOUDS IN MOST AREAS HAVE LIMITED WIDELY
SCATTERED TO SCATTERED SNOW SHOWERS TO THE NORTHWEST THIRD OF THE
FA. SNOW AMOUNTS SHOULD BE VERY LIGHT WITH GENERALLY A HALF INCH OR
LESS MAINLY ACROSS THE WESTERN ADIRONDACKS WITH ISOLATED AMOUNTS UP
TO AN INCH. WINDS ARE EXPECTED TO REMAIN SOUTHWEST AHEAD OF THE FRONT
AND THEN SHIFT TO W-NW BEHIND THE FRONT AS COLDER AIR FUNNELS INTO
OUR REGION. EXPECT LOWS TONIGHT TO GENERALLY BE IN THE 20S TO AROUND
30. HIGHS ON TUESDAY ARE EXPECTED TO RANGE FROM THE MID 20S
NORTHWEST TO MID 40S SOUTHEAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
FOR TUESDAY NIGHT THROUGH THURSDAY EXPECT HIGH PRESSURE TO BE THE
DOMINANT FEATURE AS THE FIRST HIGH PRESSURE CENTER CRESTS ACROSS
OUR REGION TUESDAY NIGHT AND THEN WEAKENS AS THE NOSE OF OF A
LARGE RIDGE OF HIGH PRESSURE OVER THE MID MISSISSIPPI VALLEY
EXTENDS INTO OUR REGION WEDNESDAY NIGHT INTO THURSDAY. THERE WILL
BE A FAST MOVING LOW PRESSURE SYSTEM PASSING SOUTH OF OUR AREA
ACROSS THE CENTRAL APPALACHIANS ON WEDNESDAY...HOWEVER THIS SYSTEM
APPEARS TOO FAR SOUTH FOR MOST OF AREA TO SEE ANY PCPN. HAVE
PLACED SLIGHT CHANCE TO LOW CHANCE POPS FOR SNOW IN THE FORECAST
ACROSS EXTREME SOUTHERN PORTION OF FA WEDNESDAY AFTERNOON INTO
WEDNESDAY EVENING. THIS AREA IS GENERALLY FROM SOUTH OF ELLENVILLE
TO POUGHKEEPSIE TO SOUTH OF TORRINGTON. EXPECT TEMPS TO BE MORE
SEASONABLE DURING THIS PERIOD. EXPECT LOWS TUESDAY NIGHT TO RANGE
FROM 5 BELOW ZERO NORTHWEST TO THE UPPER TEENS TO AROUND 20
SOUTHEAST. HIGH ON WEDNESDAY ARE EXPECTED TO BE RANGE FROM THE MID
20S NORTHWEST TO UPPER 30S SOUTHEAST. LOWS WEDNESDAY NIGHT ARE
EXPECTED TO BE IN THE UPPER SINGLE DIGITS AND LOWER TEENS
NORTHWEST TO LOWER 20S SOUTHEAST WITH HIGHS ON THURSDAY GENERALLY
IN THE 30S...EXCEPT LOWER 40S SOUTHEAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE EXTENDED PERIOD WILL BEGIN WITH AN ARCTIC FRONT APPROACHING THE
REGION. THE MODELS ARE STILL HAVING TROUBLE WITH THE EXACT TIMING OF
THIS BOUNDARY. FOR NOW...IT LOOKS LIKE OUR REGION WILL REMAIN AHEAD
OF THE BOUNDARY FOR THURSDAY NIGHT...SO MIN TEMPS WON/T BE TOO
COLD...AS A S-SW FLOW AHEAD OF THE BOUNDARY WILL KEEP MIN TEMPS IN
THE 20S FOR MOST VALLEY AREAS...WITH TEENS FOR THE HIGHER
TERRAIN...WHICH IS ABOVE NORMAL FOR THIS TIME OF YEAR.
BY FRIDAY...THE BOUNDARY WILL BEGIN TO APPROACH FROM THE NORTH. THIS
COLD FRONT WILL BE QUITE MOISTURE STARVED...SO WILL KEEP CHC POPS
ONLY TO HIGH TERRAIN OF NORTHERN AREAS. FURTHER SOUTH...SLIGHT CHC
POPS EXTEND DOWN AS FAR AS THE CAPITAL REGION. DAYTIME TEMPS SHOULD
GO ABOVE FREEZING FOR THE VALLEY AREAS...SO HAVE GONE WITH RAIN/SNOW
DEPENDING ON SFC TEMPS. PRECIP WILL BE PRETTY SPOTTY...AND MOST
AREAS OUTSIDE THE HIGH TERRAIN LOOK TO STAY DRY.
THE MODELS CONTINUE TO DISAGREE ON HOW QUICKLY THE FRONT PUSHES
SOUTH THROUGH THE AREA. THE 12 UTC ECMWF SUGGESTS THAT A WAVE
DEVELOPS ALONG THE BOUNDARY FOR FRIDAY NIGHT INTO SATURDAY...WHICH
COULD BRING SOME LIGHT SNOW TO THE AREA /QPF IS GENERALLY A TENTH OF
AN INCH OR LESS/...AS THE FRONT DROPS THROUGH OUR AREA.
MEANWHILE...THE 12 UTC GFS BRINGS THE FRONT THROUGH BY SATURDAY
MORNING...AND ALSO SHOWS A WEAK WAVE DEVELOPING ALONG THE
BOUNDARY...BUT AFTER IT CROSSES OUR AREA. THIS WAVE COULD BRING SOME
LIGHT SNOW TO MAINLY SOUTHERLY PARTS OF THE AREA BY SAT NIGHT INTO
SUNDAY. SIMILAR TO THE ECMWF...THE GFS SHOWS VERY LIGHT QPF ACROSS
OUR AREA.
FOR NOW WITH THE UNCERTAINTY REGARDING THE MODELS...HAVE GONE WITH
SLIGHT CHC/LOW CHC POPS THROUGH MUCH OF THE WEEKEND...WITH TEMPS
BELOW NORMAL. VALLEY MAX TEMPS LOOK TO BE IN THE 20S...WITH SINGLE
DIGITS TO LOW TEENS AT NIGHT. THE HIGHER TERRAIN WILL BE EVEN
COLDER...WITH TEENS TO NEAR 20 DURING THE DAY...AND MIN TEMPS NEAR
ZERO AT NIGHT. IT COULD EVEN BE COLDER...AS THE 12 UTC ECMWF SHOWS
THE POLAR VORTEX DROPPING TOWARDS THE REGION...AND ALLOWING 850 HPA
TEMPS OF -20 TO -25 DEGREES ACROSS THE AREA BY LATE IN THE WEEKEND.
AT THIS POINT...WE WON/T GO WITH THIS SCENARIO QUITE YET...BUT THE
POTENTIAL FOR A FEW VERY COLD DAYS BY LATE IN THE WEEKEND/EARLY NEXT
WEEK IS POSSIBLE. ALSO...THE MODELS CONTINUE TO SHOW PRECIP BELOW
NORMAL...AS MOISTURE WILL BE QUITE LIMITED ACROSS THE AREA.
&&
.AVIATION /06Z MONDAY THROUGH SATURDAY/...
COLD FRONT CROSSING THE REGION THROUGH THE EARLY MORNING HOURS. A
SOLID CEILING AT AROUND 3500-5000 FEET IS SINKING SOUTH AND WILL
AFFECT KGFL AND KALB BY 06Z-07Z. IT SHOULD TAKE UNTIL ABOUT MIDDAY
FOR THE CLOUDS TO GET TO KPOU. THE CEILING COULD LOWER TO 2500 FEET
AT KGFL AFTER SUNRISE...BUT THE CLOUDS AT ALL THREE SITES WILL TEND
TO BREAK UP THROUGH THE AFTERNOON. ONLY SCATTERED CLOUDS ABOVE 3000
FEET ARE EXPECTED THIS EVENING.
SOUTHWEST TO NORTHWEST WINDS BELOW 10 KT WILL BECOME NORTH TO
NORTHWEST NEAR 10 KT BY MIDDAY...THE BECOME LIGHT AGAIN THIS EVENING.
OUTLOOK...
TUE NGT-SAT...MAINLY VFR...NO SIG WX.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT 5 DAYS. ANY PCPN
WILL BE IN THE FORM OF LIGHT SNOW SHOWERS NORTHWEST LATER TONIGHT
INTO TUESDAY MORNING AND ACROSS FAR SOUTHERN PORTION OF THE FA
WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING. REMAINDER OF FA IS
EXPECTED TO BE DRY. SOME GAGES ARE STILL BEING IMPACTED BY ICE
ACROSS NORTHERN PORTIONS OF THE HSA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/11/WASULA
NEAR TERM...GJM/FRUGIS/11/WASULA
SHORT TERM...11
LONG TERM...FRUGIS
AVIATION...NAS
HYDROLOGY...11
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
330 AM EST Tue Feb 7 2012
Updated for 12Z aviation discussion.
.SYNOPSIS...
07Z water vapor and H4 RUC analysis shows a complex and disorganized
upper level pattern across the CONUS this morning. Southern stream
flow extends northeastward from central Mexico to the SE States.
Associated with this flow, abundant mid/upper level moisture and
resulting cloudiness is streaming across our skies. One subtle
shortwave impulse is noted embedded within the flow over the
north-central Gulf of Mexico. Weak synoptic lift associated with
this energy is approaching our region from the west with some
enhancement/cooling cloud tops noted on IR satellite imagery. This
lift may be just enough to support a few light showers/sprinkles
this morning across mainly the SE half of the area.
At the surface, forecast area resides between 1025mb high pressure
over the western TN valley, and a decaying frontal boundary over the
central FL peninsula. Resulting gradient is supplying the area with
a light NE low level flow, and an expanding area of lower level
stratus.
&&
.SHORT TERM (TODAY THROUGH THURSDAY)...
Today,
Weak shortwave impulse mentioned above in the synopsis will approach
and cross the forecast area through the early afternoon hours. Swath
of deep layer synoptic support/QG-forcing ahead of this impulse will
also overspread the area and may be sufficient to support a few
widely sct light showers/sprinkles. Best chances of seeing a brief
shower will be south and east of a line from Panama City to
Tallahassee, and Valdosta. GFS/SREF are most aggressive with the
shower activity, while the higher resolution CAM models are barely
forcing any activity at all. Either way, any showers will be of very
low impact, and likely barely enough to wet the ground. Large scale
forcing will be quickly exiting to the east by mid-afternoon, and
will end any slight shower chances in the grids. Likely will see a
scattering of sunny breaks, especially during the afternoon, but
overall will highlight a mostly cloudy forecast with high temps into
the upper 60s/lower 70s.
Tonight,
Upper level energy will eject eastward from the Central Plains to
the TN valley dragging an associated surface front across the lower
MS valley and toward our western borders. Current timing looks to
bring the front into our SE AL/FL panhandle zones around sunrise.
Good model agreement in keeping any significant synoptic forcing to
our north, and this being a dry frontal passage for our area. Low
temperatures will be seasonable ranging from the middle 40s to lower
50s.
Wednesday/Wednesday Night,
Upper level shortwave will pivot eastward and off the mid-Atlantic
coast dragging the surface front to our east by the end of the day.
Not a big supply of colder air to work with in the wake of this
front, and only looking for modest CAA. In fact, good diurnal mixing
behind the front will likely make up for much of the CAA, and still
anticipate high temperatures to reach the upper 60s to lower 70s.
Clearing skies and drier low levels will allow temperatures to reach
the upper 30s and lower 40s across many inland areas by sunrise
Thursday morning. At it looks now, with the high center well to our
NW, the gradient will hold tight and prevent any significant
radiational cooling. With this in mind do not presently expect any
threat of freezing temps (or even frost) Thursday morning.
Thursday,
Dry, pleasant, and seasonable weather appears on tap as surface high
pressure dominates the deep south. Grids will show an increase in
high level clouds late in the day as the ECMWF/GFS forecast a
series of mid-level southern stream impulses ejecting eastward along
the northern Gulf Coast.
&&
.LONG TERM (FRIDAY THROUGH NEXT TUESDAY)...
The extended period begins with zonal flow in the mid-upper levels
across the local region. A cut off low will be near the southern tip
of Baja California and a trough will be digging across the upper
Midwest and Great Lakes region as strong short wave energy drops
south out of central Canada. The 00z GFS and 00z EURO are in better
agreement than previous model runs especially through the end of the
week. Their solutions diverge somewhat over the weekend and early
next week although local differences don`t appear that significant.
Both models show the aforementioned trough continuing to deepen over
the eastern CONUS Friday sending a dry cold front through the CWA
Friday night/Saturday morning. If a surface low does develop over
the western GOMEX as advertised by both models, this feature should
track well south of our FA to keep rain chances out of the forecast.
A drier airmass filters in over the weekend along with cooler
temperatures in the wake of the cold front. However no freezes are
expected as the core of the airmass should stay well to our north.
As the axis of the trough slides to our east, we will see a brief
period of zonal flow Sunday before the next shortwave and cold front
bring rain chances to the region early next week. Temperatures will
be near or below seasonal norms through most of the period.
&&
.MARINE...
Generally light northerly flow will continue through tonight behind
a decaying frontal boundary across the central Florida Peninsula.
Another weak cold front will cross the forecast waters on Wednesday,
followed by a period of cautionary level offshore winds Wednesday
night into Thursday morning.
&&
.AVIATION (THROUGH 12Z WEDNESDAY)...
IFR/MVFR CIGS early this morning will gradually lift, with VFR
conditions expected by afternoon. Winds will remain light throughout
the day. Low clouds are not expected to be an issue again tonight.
&&
.FIRE WEATHER...
Drier air will filter into the area behind a cold front Wednesday
and Thursday. Minimum relative humidity values will drop below 35
percent for a portion of our north Florida zones Wednesday and most
or all of north Florida Thursday. However, ERC values, wind and
dispersions will not meet Red Flag criteria.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 72 47 74 41 66 / 10 10 10 0 10
Panama City 70 52 72 46 65 / 10 10 10 0 10
Dothan 69 46 70 40 63 / 10 10 10 0 10
Albany 69 44 70 39 63 / 10 10 10 0 10
Valdosta 69 46 73 41 65 / 10 10 10 0 10
Cross City 74 50 75 43 68 / 20 10 10 0 10
Apalachicola 69 51 70 46 65 / 20 10 10 0 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BARRY
AREA FORECAST DISCUSSION
NWS LINCOLN IL
851 PM CST WED FEB 8 2012
.DISCUSSION...
ISSUED 851 PM CST WED FEB 8 2012
THE WESTERN AND NORTHERN EDGE OF THE CLOUDS IS BEGINNING TO MAKE
SOME PROGRESS INTO CENTRAL ILLINOIS. HOW SOON THE CLOUDS CLEAR OUT
AND IF THE CLEARING CONTINUES THROUGH MORNING WILL PLAY A MAJOR
ROLL IN LOW TEMPS FOR TONIGHT. SUBSIDENCE INVERSIONS UNDER HIGH
PRESSURE CAN TRAP LOW MOISTURE THAT FORM STRATUS CLOUDS WHICH FILL
IN AGAIN OR RETROGRADE BACK TO THE N-NE. THERE APPEARS TO BE
ENOUGH OF A CLEARING AREA ACROSS N MO/IOWA TO KEEP OUR CLEARING
TRENDS GOING. HAVE TRENDED SLOWER WITH THE CLEARING BASED ON
SATELLITE TRENDS AND THE LATEST HRRR MODEL OUTPUT.
THE SURFACE RIDGE APPEARS TO BE MAINLY SETTLING TO THE SOUTH
INSTEAD OF SLIDING EAST INTO ILLINOIS...SO THAT GIVES MORE
CONFIDENCE TO THE CLEARING SCENARIO. KEPT THE FORECAST LOWS SLIGHTLY
BELOW GUIDANCE...AND WE MAY NOT BE COLD ENOUGH. SURFACE DEWPOINTS
ARE QUITE DRY JUST TO OUR N AND W. WOULD NOT BE SURPRISED TO SEE
SOME MID TEENS REPORTED IN OUR NW COUNTIES IN THE MORNING. FOR
NOW...KEPT UPPER TEENS AND LOW 20S IN PLACE.
NO OTHER CHANGES WERE NEEDED TO THE CURRENT FORECAST/GRIDS.
UPDATED INFO IS ALREADY AVAILABLE.
SHIMON
&&
.AVIATION...
ISSUED 533 PM CST WED FEB 8 2012...FOR THE 00Z TAFS
MVFR CIGS ARE LINGERING NEAR PIA/BMI WITH VFR CIGS AT 3-4K FT AT
SPI/DEC/CMI. THE CLEARING LINE IS VERY CLOSE TO THE NORTH AT
PIA/BMI...BUT WESTERLY WINDS MAY SLOW THE SOUTHWARD PROGRESSION OF
THAT CLEARING LINE. PILOT REPORTS SHOW THE CLOUD LAYER ALMOST 2K
FT THICK...SO THE CLEARING WILL HAVE TO COME FROM ACTUAL MOVEMENT
OF THE CLOUD MASS. ALL THE MODELS SHOW ENOUGH DRY AIR PUSHING IN
FROM THE WEST BY 06Z TO CREATE CLEARING AT ALL TERMINAL SITES
TONIGHT. WILL CONTINUE WITH THE CLEARING TREND...BUT DELAY IT BY
3-4 HOURS THAN PREVIOUSLY INDICATED.
WINDS WILL REMAIN AOB 10KTS FROM THE WNW TONIGHT...THEN WSW
TOMORROW.
LIGHT MVFR FOG MAY DEVELOP IN AREAS THAT SEE CLEARING SKIES THE
LONGEST...ESPECIALLY PIA/BMI AND CMI ACROSS THE NORTH. HAVE LEFT A
TEMPO FOR MVFR FOG IN ALL TAFS AS CLEARING IS STILL EXPECTED TO
DEVELOP EVERYWHERE BY 06Z.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 305 PM CST WED FEB 8 2012
SHORT TERM...TONIGHT THROUGH SATURDAY...
LARGE AREA OF HIGH PRESSURE OVER THE PLAINS WILL MOVE SOUTHEAST AND
DOMINATE THE WEATHER OVER IL TONIGHT THROUGH THURSDAY NIGHT.
EXTENSIVE CLOUD COVER OVER THE AREA WILL MOVE SLOWLY SOUTH WITH MOST
AREAS SEEING CLEAR SKIES BY SUNRISE. THE MAIN WEATHER FEATURE FOR
THE SHORT TERM WILL BE A STRONG COLD FRONT THAT WILL MOVE THROUGH
THE AREA ON FRIDAY. BY MIDDAY...THE FRONT SHOULD BE ABOUT MIDWAY
THROUGH THE FORECAST AREA...THEN INTO THE OHIO VALLEY BY 00Z SAT.
WITH THE CURRENT HIGH PRESSURE HAVING PUSHED MUCH OF THE QUALITY
MOISTURE FAR TO THE SOUTH...IT WILL TAKE SOME TIME FOR IT TO MAKE A
RETURN AND MAY NOT MAKE IT TO CENTRAL IL IN TIME TO INTERACT WITH
THE FRONT. SOME OF THE SHORT RANGE MODELS ARE PAINTING SOME QPF OVER
EASTERN IL WITH THE FRONT...SO WILL CONTINUE WITH SOME SLIGHT CHANCE
POPS THERE. AFTER THAT...THE LARGE CANADIAN AIRMASS IN THE WAKE OF
THE FRONT WILL SPREAD OVER THE CENTRAL/EASTERN CONUS BRINGING
TEMPERATURES BACK TO WINTER-TIME LEVELS STARTING FRIDAY NIGHT AND
LASTING INTO THE EXTENDED PERIOD. FOR NOW...IT APPEARS THAT FRIDAY
NIGHT INTO SATURDAY WILL BE THE COLDEST WITH LOWS 10-20 AND HIGHS IN
THE 20S.
LONG TERM...SUNDAY THROUGH WEDNESDAY...
THE GFS AND ECMWF ARE IN AGREEMENT THAT AN UPPER SHORTWAVE WILL COME
OUT OF THE SOUTHERN ROCKIES AND INTO THE PLAINS EARLY NEXT WEEK. BY
THEN...THE CANADIAN HIGH WILL BE OFF THE EAST COAST AND MOISTURE
FROM THE GULF WILL STREAM NORTHWARD THROUGH THE MS VALLEY. POPS WILL
BEGIN RISING ON MONDAY AS LIGHT SNOW...PERHAPS MIXED WITH LIGHT RAIN
AT THE START...MOVES INTO THE WESTERN HALF OF IL. HIGHEST CHANCE OF
PRECIPITATION WILL BE MONDAY NIGHT WITH THE PASSAGE OF THE UPPER
WAVE. ANY SURFACE REFLECTION OF THIS SYSTEM WILL BE SUBTLE/WEAK AND
THEREFORE THE QPF FORECASTS ARE ON THE LOW SIDE DUE TO THE LACK OF
LOW LEVEL FOCUS.
MODEL AGREEMENT ENDS THERE AS THE NEXT STORM SYSTEM/UPPER LOW COMES
INTO THE SOUTHERN ROCKIES BY TUESDAY. THE GFS SIMPLY KEEPS THE LOW
CHUGGING INTO THE PLAINS AND THROUGH THE MIDWEST ON WEDNESDAY...
WHILE THE ECMWF HOLDS IT BACK WELL TO THE WEST THROUGH THIS PERIOD.
SOME OF THE AUTOMATED POP GUIDANCE IS OBVIOUSLY WEIGHTED TOWARD THE
GFS...WITH LIKELY POPS ON WEDNESDAY. USUALLY...SLOWER IS BETTER WITH
SOUTHWESTERN UPPER LOWS...SO WILL KNOCK DOWN POPS INTO THE CHANCE
RANGE. POPS MAY BE DELAYED EVEN FURTHER IF THE ECMWF ENDS UP BEING
THE WINNING MODEL.
04
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
929 PM EST WED FEB 8 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL MOVE INTO THE AREA BRINGING DRY WEATHER TO
CENTRAL INDIANA THROUGH THURSDAY. AN ARCTIC COLD FRONT WILL MOVE
THROUGH ON FRIDAY BRINGING COLDER THAN AVERAGE TEMPERATURES ALONG
WITH A CHANCE FOR SNOW. ANOTHER FRONT WILL ARRIVE BY MID-WEEK NEXT
WEEK.
&&
.NEAR TERM /OVERNIGHT/...
SATELLITE IMAGES INDICATE CLOUDS OVER CENTRAL INDIANA SLOWLY
CLEARING FROM NORTHWEST TO SOUTHEAST. RUC RH PROFILES SUGGEST
CLOUD SHOULD DEPART TO THE SOUTHEAST AS THE NIGHT
PROGRESSES. THUS MADE SOME MINOR TWEAKS TO SKY GRIDS TO INCREASE
CLEARING GRADIENT...PARTICULARLY ACROSS THE NORTHERN PARTS OF THE
FORECAST AREA.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR PRECIPITATION FRIDAY AND SATURDAY. FOR THE
MOST PART...MODELS ARE SIMILAR ENOUGH THAT A BLEND CAN BE USED.
HIGH PRESSURE WILL PROVIDE DRY CONDITIONS FOR THURSDAY AND
THURSDAY NIGHT UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES.
GENERALLY STUCK WITH MAV MOS...ALTHOUGH WENT A BIT WARMER THAN MAV
MOS SOME AREAS THURSDAY NIGHT WITH AN INCREASE IN CLOUD COVER
EXPECTED.
THE COLD FRONT WILL MOVE INTO THE AREA ON FRIDAY INTO FRIDAY
NIGHT. ALTHOUGH IT WILL NOT HAVE A LOT OF MOISTURE WITH
IT...ARCTIC FRONTS TEND TO BE ABLE TO SQUEEZE OUT MORE THAN
EXPECTED. THUS RAISED MOS POPS FRIDAY AND FRIDAY NIGHT...BUT STUCK
TO NO HIGHER THAN THE CHANCE CATEGORY.
BASED ON EXPECTED BOUNDARY LAYER TEMPERATURES AHEAD OF THE
FRONT...WENT WITH A RAIN/SNOW MIX ACROSS THE SOUTH HALF OF THE
AREA BY FRIDAY AFTERNOON. FOR FRIDAY NIGHT WENT ALL SNOW AS COLDER
AIR MOVES IN.
SOME OF THE LAKE EFFECT SNOW SHOWERS THAT DEVELOP SATURDAY MAY
SNEAK INTO THE NORTHWEST FORECAST AREA...SO WENT SLIGHT CHANCE
POPS THERE. OTHERWISE IT LOOKS LIKE DRY BUT COLD CONDITIONS WILL
BE THE RULE SATURDAY.
WITH CLOUDS AROUND FRIDAY NIGHT...WENT WARMER THAN MAV MOS FOR
LOWS. STUCK WITH A BLEND FOR SATURDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH A 1035-40MB SURFACE HIGH ACROSS THE NORTHERN
PLAINS AND THE FORECAST AREA ON SUBSIDENCE SIDE OF AN UPPER WAVE
ASSOCIATED WITH THE STRONG UPPER LOW JUST EAST OF THE HUDSON BAY IN
QUEBEC. FORTUNATELY OR UNFORTUNATELY...DEPENDING ON WHAT YOU
PREFER...THE BULK OF THE COLDEST AIR WILL BE NORTHEAST OF THE FORECAST
AREA CLOSER TO THE CENTER OF THE UPPER LOW. THE TWO MAIN WEATHER
FEATURES FOR THE EXTENDED TIMEFRAME APPEAR IN DAYS 6/7...AS A COUPLE
UPPER LEVEL WAVES EJECT FROM THE LOWER ROCKIES AND PUSH EAST TOWARD
THE OHIO RIVER VALLEY. MID/LONG RANGE MODEL SOLNS ARE IN FAIRLY GOOD
AGREEMENT WITH THE HANDLING OF THE INITIAL WAVE ON MONDAY NIGHT INTO
TUESDAY AND WITH COLD AIR ALREADY IN PLACE...SNOW IS EXPECTED IN
ALL BUT THE BOTTOM TWO TIER OF COUNTIES WHERE FORECAST SOUNDINGS
ILLUSTRATE A RAIN/SNOW MIX MAY OCCUR. UPPED POPS AREA-WIDE FOR
THIS INITIAL SYSTEM AS MODEL AGREEMENT AND CONSISTENCY HAS BOOST
CONFIDENCE IN ITS OCCURRENCE.
TIMING OF THE SECOND SHORTWAVE IS A LITTLE TRICKIER...AS THE ECMWF
AMPLIFIES UPPER RIDGING AHEAD OF THIS SECOND WAVE MORE THAN THE
GFS. THIS WILL ACT TO SLOW THE SYSTEM A GOOD FULL DAY LATER THAN
THE GFS. WITH MORE MOISTURE TO WORK WITH THAN THE INITIAL
SHORTWAVE...THE TRACK OF THE SURFACE LOW WILL BE IMPORTANT IN
DETERMINING PRECIP TYPE.
&&
.AVIATION /DISCUSSION FOR THE 090300Z KIND TAF UPDATE/...
BACK EDGE OF AN AREA OF MVFR CEILINGS... LOCATED ABOUT 70SM
NORTHWEST OF KIND AT THIS TIME. CLEARING LINE IS STARTING TO SLOW
DOWN. WILL DELAY THE SCATTERING OUT OF THE MVFR CEILINGS...TO ABOUT
090800Z. NO OTHER SIGNIFICANT CHANGES MADE AT THIS TIME. PREVIOUS
DISCUSSION FOLLOWS.
BACK EDGE OF MVFR CEILINGS 020-030 PROGRESSING SOUTHEAST ACROSS
NORTHERN ILLINOIS AND NORTHWEST INDIANA. SHORT TERM MODEL DATA AND
EXTRAPOLATION SUGGESTS THESE CEILINGS SHOULD SCATTER OUT FROM THE
NORTHWEST OVER THE TAF SITES BETWEEN 090300Z-090800Z. SOME CONCERN
ABOUT FOG DEVELOPMENT LATE TONIGHT IN THE WAKE OF CLEARING...BUT
GIVEN THE ADVECTION OF LOWER SURFACE DEWPOINTS UPSTREAM...WILL HOLD
OFF ON ANY VISIBILITY RESTRICTIONS AT THIS TIME.
NO WIND ISSUES EXPECTED THROUGH 091200Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...PUMA
SHORT TERM...50
LONG TERM....MRD
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
914 PM EST WED FEB 8 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WILL MOVE INTO THE AREA BRINGING DRY WEATHER TO
CENTRAL INDIANA THROUGH THURSDAY. AN ARCTIC COLD FRONT WILL MOVE
THROUGH ON FRIDAY BRINGING COLDER THAN AVERAGE TEMPERATURES ALONG
WITH A CHANCE FOR SNOW. ANOTHER FRONT WILL ARRIVE BY MID-WEEK NEXT
WEEK.
&&
.NEAR TERM /OVERNIGHT/...
SATELLITE IMAGES INDICATE CLOUDS OVER CENTRAL INDIANA SLOWLY
CLEARING FROM NORTHWEST TO SOUTHEAST. RUC RH PROFILES SUGGEST
CLOUD SHOULD DEPART TO THE SOUTHEAST AS THE NIGHT
PROGRESSES. THUS MADE SOME MINOR TWEAKS TO SKY GRIDS TO INCREASE
CLEARING GRADIENT...PARTICULARLY ACROSS THE NORTHERN PARTS OF THE
FORECAST AREA.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR PRECIPITATION FRIDAY AND SATURDAY. FOR THE
MOST PART...MODELS ARE SIMILAR ENOUGH THAT A BLEND CAN BE USED.
HIGH PRESSURE WILL PROVIDE DRY CONDITIONS FOR THURSDAY AND
THURSDAY NIGHT UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES.
GENERALLY STUCK WITH MAV MOS...ALTHOUGH WENT A BIT WARMER THAN MAV
MOS SOME AREAS THURSDAY NIGHT WITH AN INCREASE IN CLOUD COVER
EXPECTED.
THE COLD FRONT WILL MOVE INTO THE AREA ON FRIDAY INTO FRIDAY
NIGHT. ALTHOUGH IT WILL NOT HAVE A LOT OF MOISTURE WITH
IT...ARCTIC FRONTS TEND TO BE ABLE TO SQUEEZE OUT MORE THAN
EXPECTED. THUS RAISED MOS POPS FRIDAY AND FRIDAY NIGHT...BUT STUCK
TO NO HIGHER THAN THE CHANCE CATEGORY.
BASED ON EXPECTED BOUNDARY LAYER TEMPERATURES AHEAD OF THE
FRONT...WENT WITH A RAIN/SNOW MIX ACROSS THE SOUTH HALF OF THE
AREA BY FRIDAY AFTERNOON. FOR FRIDAY NIGHT WENT ALL SNOW AS COLDER
AIR MOVES IN.
SOME OF THE LAKE EFFECT SNOW SHOWERS THAT DEVELOP SATURDAY MAY
SNEAK INTO THE NORTHWEST FORECAST AREA...SO WENT SLIGHT CHANCE
POPS THERE. OTHERWISE IT LOOKS LIKE DRY BUT COLD CONDITIONS WILL
BE THE RULE SATURDAY.
WITH CLOUDS AROUND FRIDAY NIGHT...WENT WARMER THAN MAV MOS FOR
LOWS. STUCK WITH A BLEND FOR SATURDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH A 1035-40MB SURFACE HIGH ACROSS THE NORTHERN
PLAINS AND THE FORECAST AREA ON SUBSIDENCE SIDE OF AN UPPER WAVE
ASSOCIATED WITH THE STRONG UPPER LOW JUST EAST OF THE HUDSON BAY IN
QUEBEC. FORTUNATELY OR UNFORTUNATELY...DEPENDING ON WHAT YOU
PREFER...THE BULK OF THE COLDEST AIR WILL BE NORTHEAST OF THE FORECAST
AREA CLOSER TO THE CENTER OF THE UPPER LOW. THE TWO MAIN WEATHER
FEATURES FOR THE EXTENDED TIMEFRAME APPEAR IN DAYS 6/7...AS A COUPLE
UPPER LEVEL WAVES EJECT FROM THE LOWER ROCKIES AND PUSH EAST TOWARD
THE OHIO RIVER VALLEY. MID/LONG RANGE MODEL SOLNS ARE IN FAIRLY GOOD
AGREEMENT WITH THE HANDLING OF THE INITIAL WAVE ON MONDAY NIGHT INTO
TUESDAY AND WITH COLD AIR ALREADY IN PLACE...SNOW IS EXPECTED IN
ALL BUT THE BOTTOM TWO TIER OF COUNTIES WHERE FORECAST SOUNDINGS
ILLUSTRATE A RAIN/SNOW MIX MAY OCCUR. UPPED POPS AREA-WIDE FOR
THIS INITIAL SYSTEM AS MODEL AGREEMENT AND CONSISTENCY HAS BOOST
CONFIDENCE IN ITS OCCURRENCE.
TIMING OF THE SECOND SHORTWAVE IS A LITTLE TRICKIER...AS THE ECMWF
AMPLIFIES UPPER RIDGING AHEAD OF THIS SECOND WAVE MORE THAN THE
GFS. THIS WILL ACT TO SLOW THE SYSTEM A GOOD FULL DAY LATER THAN
THE GFS. WITH MORE MOISTURE TO WORK WITH THAN THE INITIAL
SHORTWAVE...THE TRACK OF THE SURFACE LOW WILL BE IMPORTANT IN
DETERMINING PRECIP TYPE.
&&
.AVIATION /DISCUSSION FOR THE 090000Z TAFS/...
BACK EDGE OF MVFR CEILINGS 020-030 PROGRESSING SOUTHEAST ACROSS
NORTHERN ILLINOIS AND NORTHWEST INDIANA. SHORT TERM MODEL DATA AND
EXTRAPOLATION SUGGESTS THESE CEILINGS SHOULD SCATTER OUT FROM THE
NORTHWEST OVER THE TAF SITES BETWEEN 090300Z-090800Z. SOME CONCERN
ABOUT FOG DEVELOPMENT LATE TONIGHT IN THE WAKE OF CLEARING...BUT
GIVEN THE ADVECTION OF LOWER SURFACE DEWPOINTS UPSTREAM...WILL HOLD
OFF ON ANY VISIBILITY RESTRICTIONS AT THIS TIME.
NO WIND ISSUES EXPECTED THROUGH 091200Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...PUMA
SHORT TERM...50
LONG TERM....MRD
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
545 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 INTO WEDNESDAY MORNING/...
FORECAST FOCUS IS ON POPS/TIMING/SNOWFALL AMOUNTS WITH RESPECT TO UPPER
WAVE MOVING THROUGH OVERNIGHT. CONFIDENCE IN ACCUMULATING SNOWFALL
OCCURRING OVER MUCH OF CENTRAL INDIANA HAS INCREASED WITH LATEST
MODEL RUNS AS UPPER FORCING SHOWN OVER LAST FEW DAYS IS STILL THERE
BUT IS NOW JOINED BY VERY WEAK FRONTOGENESIS...INCREASED DEEP LAYER
MOISTURE...AND A BIT OF INSTABILITY. GFS/NAM/SREFS/ECMWF ALL IN
AGREEMENT ON THIS WAVE AND SOME MEASURABLE QPF AS WELL. THIS WAVE
WILL COME TOGETHER AND MOVE ACROSS SOUTHERN INDIANA DURING THE
OVERNIGHT HOURS INTO THE MORNING. CONSENSUS OF TIMING SHOWS BEST
FORCING OVER THE AREA BETWEEN 9 AND 15Z SO CONFINED HIGHEST POPS TO
THAT TIME WITH LOW CHANCES IN THE NORTHEAST INCREASING TO LIKELIES
ALONG I70 AND SOUTH AND FINALLY CATEGORICAL SNOW IN THE FAR SOUTH.
PRIOR TO THIS WILL SLOWLY RAMP POPS UP WITH ONLY SLIGHT CHANCE PRIOR
TO 6Z AND THEN CHANCES SPREADING NORTHEAST OVER THE AREA FROM 6-9Z.
AS FAR AS PRECIPITATION TYPE IS CONCERNED...MOST MODEL FIELDS ARE
INDICATING ALL SNOW FOR THE ENTIRE AREA...BUT NAM THICKNESSES START
OUT MARGINAL AND RUC SOUNDINGS SHOW POTENTIAL FOR A RAIN SNOW MIX
EARLY IN THE SOUTH. THEREFORE WILL CARRY LOW CHANCES FOR A RAIN SNOW
MIX IN THE SOUTHERN TWO TIERS THROUGH 6Z AND ALL SNOW THEREAFTER.
AS FAR AS AMOUNTS ARE CONCERNED...WITH THE BEST FORCING IN THE SOUTH
WILL GO WITH HIGHEST AMOUNTS THERE. GENERALLY AROUND AN INCH TOTAL
IN THE SOUTH WITH LOCALLY HIGHER AMOUNTS POSSIBLE...HALF AN INCH TO
AN INCH CENTRAL...AND ONLY AROUND A TENTH OF AN INCH IN THE
NORTHWEST IF ANY ACCUMULATION AT ALL AS IT IS FURTHEST FROM THE
FORCING. WHILE HIGHEST AMOUNTS ARE ONLY AROUND AN INCH THE TIMING
WILL BE PROBLEMATIC AS SNOW WILL BEGIN IN THE WEE HOURS OF THE
MORNING AND CONTINUE THROUGH MID MORNING...IMPACTING THE MORNING
COMMUTE. WILL ISSUE AN SPS TO HIGHLIGHT THE TIMING FACTOR.
FOR LOW TEMPERATURES GUIDANCE WAS IN GOOD AGREEMENT SO USED AN
AVERAGE IN THE MID 20S TO LOW 30S.
&&
.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 080000Z TAFS/...
LOWER CONFIDENCE CEILING FORECAST THIS EVENING AS THE EDGE OF AN
MVFR DECK EXISTS BETWEEN KIND/KHUF/KBMG. THE EDGE HAS BEEN
RETREATING A BIT TO THE NORTHEAST OVER THE PAST COUPLE OF
HOURS...HOWEVER THE LOW LEVEL NORTHEAST FLOW AND SHORT TERM MODELS
SUGGEST THE EDGE WILL BEGIN DRIFTING BACK TO THE SOUTHWEST LATER
THIS EVENING. FOR NOW WILL KEEP MVFR CEILINGS AT KLAF/KIND...AND GO
WITH TEMPORARY MVFR CEILINGS AT KHUF/KBMG...WITH PREVIALING MVFR
CEILINGS OVERSPREADING ALL THE TAF SITES BY 080500Z.
OTHER ITEM OF INTEREST OVERNIGHT WILL BE THE SYSTEM CURRENTLY MOVING
THROUGH IOWA AND MISSOURI. HIGHER RESOLUTION SHORT TERM MODELS
SUGGEST THERE IS GOOD POTENTIAL FOR FAIRLY WIDESPREAD IFR VISIBILITY
RESTRICTIONS IN LIGHT SNOW ACROSS THE AREA AFTER ABOUT 080900Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....JH
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
337 PM EST TUE FEB 7 2012
.UPDATE...
AVIATION SECTIONS UPDATED
&&
.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 INTO WEDNESDAY MORNING/...
FORECAST FOCUS IS ON POPS/TIMING/SNOWFALL AMOUNTS WITH RESPECT TO UPPER
WAVE MOVING THROUGH OVERNIGHT. CONFIDENCE IN ACCUMULATING SNOWFALL
OCCURRING OVER MUCH OF CENTRAL INDIANA HAS INCREASED WITH LATEST
MODEL RUNS AS UPPER FORCING SHOWN OVER LAST FEW DAYS IS STILL THERE
BUT IS NOW JOINED BY VERY WEAK FRONTOGENESIS...INCREASED DEEP LAYER
MOISTURE...AND A BIT OF INSTABILITY. GFS/NAM/SREFS/ECMWF ALL IN
AGREEMENT ON THIS WAVE AND SOME MEASURABLE QPF AS WELL. THIS WAVE
WILL COME TOGETHER AND MOVE ACROSS SOUTHERN INDIANA DURING THE
OVERNIGHT HOURS INTO THE MORNING. CONSENSUS OF TIMING SHOWS BEST
FORCING OVER THE AREA BETWEEN 9 AND 15Z SO CONFINED HIGHEST POPS TO
THAT TIME WITH LOW CHANCES IN THE NORTHEAST INCREASING TO LIKELIES
ALONG I70 AND SOUTH AND FINALLY CATEGORICAL SNOW IN THE FAR SOUTH.
PRIOR TO THIS WILL SLOWLY RAMP POPS UP WITH ONLY SLIGHT CHANCE PRIOR
TO 6Z AND THEN CHANCES SPREADING NORTHEAST OVER THE AREA FROM 6-9Z.
AS FAR AS PRECIPITATION TYPE IS CONCERNED...MOST MODEL FIELDS ARE
INDICATING ALL SNOW FOR THE ENTIRE AREA...BUT NAM THICKNESSES START
OUT MARGINAL AND RUC SOUNDINGS SHOW POTENTIAL FOR A RAIN SNOW MIX
EARLY IN THE SOUTH. THEREFORE WILL CARRY LOW CHANCES FOR A RAIN SNOW
MIX IN THE SOUTHERN TWO TIERS THROUGH 6Z AND ALL SNOW THEREAFTER.
AS FAR AS AMOUNTS ARE CONCERNED...WITH THE BEST FORCING IN THE SOUTH
WILL GO WITH HIGHEST AMOUNTS THERE. GENERALLY AROUND AN INCH TOTAL
IN THE SOUTH WITH LOCALLY HIGHER AMOUNTS POSSIBLE...HALF AN INCH TO
AN INCH CENTRAL...AND ONLY AROUND A TENTH OF AN INCH IN THE
NORTHWEST IF ANY ACCUMULATION AT ALL AS IT IS FURTHEST FROM THE
FORCING. WHILE HIGHEST AMOUNTS ARE ONLY AROUND AN INCH THE TIMING
WILL BE PROBLEMATIC AS SNOW WILL BEGIN IN THE WEE HOURS OF THE
MORNING AND CONTINUE THROUGH MID MORNING...IMPACTING THE MORNING
COMMUTE. WILL ISSUE AN SPS TO HIGHLIGHT THE TIMING FACTOR.
FOR LOW TEMPERATURES GUIDANCE WAS IN GOOD AGREEMENT SO USED AN
AVERAGE IN THE MID 20S TO LOW 30S.
&&
.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 21Z IND TAF UPDATE/...
EXTENSIVE MVFR CIGS REMAIN OVER THE IND TAF SITE AS WELL AS
UPSTREAM...THUS HAVE ELECTED TO PUSH BACK THE BRIEF PERIOD OF
3000 FT CIGS UNTIL EARLY THIS EVENING.
PREVIOUS DISCUSSION BELOW
/DISCUSSION FOR 071800Z TAF ISSUANCE/...
MVFR CEILINGS WITH STRATUS WERE THE RULE OVER MUCH OF THE REGION AT
MIDDAY. THERE ARE SOME SIGNS KBMG MAY BEGINNING TO BREAK OUT OF THE
STRATUS AS THE THE SOUTHERN PORTIONS BEGINS ERODING. OTHER SITES
COULD SCATTER OUT BY LATE AFTERNOON. BUT MODEL SOUNDINGS STILL SHOW
A SOMEWHAT MOIST LAYER RIGHT UNDER A LOW LEVEL INVERSION. SO FOR NOW
WILL KEEP MOST OTHER AREAS BROKEN WITH POSSIBLE EXCEPTION OF KHUF.
EITHER CASE CEILINGS SHOULD IMPROVE TO 25 HND TO 3 THOUSAND BY 22Z
AS SOME LOW LEVEL HEATING OCCURS.
AFTER THE IMPROVEMENT LATE TODAY...ATTENTION SHIFTS TO UPPER TROUGH
OVER THE CENTRAL PLAINS WHICH WILL MOVE OUR WAY LATE TONIGHT. THIS
SYSTEM WILL BRING LIGHT SNOW TO MOST SITES BEGINNING AROUND 08Z AND
POSSIBLE MIXED RAIN/SNOW AT KBMG. THIS WILL CAUSE A LOWERING OF
FLIGHT CONDITIONS WITH SOME AREAS BECOMING IFR. MUCH OF THIS WILL
MOVE OUT BY 15Z AND MVFR CEILINGS WILL BE THE RULE AND SOME SITES
MAY BECOME VFR AFTER 18Z WEDNESDAY. WINDS WILL BE 6 KNOTS OR LESS
THE REST OF TODAY AND TONIGHT AND NORTH 8 TO 10 KNOTS ON WEDNESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....JH
AVIATION...JH/JP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
255 PM EST TUE FEB 7 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
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 INTO WEDNESDAY MORNING/...
FORECAST FOCUS IS ON POPS/TIMING/SNOWFALL AMOUNTS WITH RESPECT TO UPPER
WAVE MOVING THROUGH OVERNIGHT. CONFIDENCE IN ACCUMULATING SNOWFALL
OCCURRING OVER MUCH OF CENTRAL INDIANA HAS INCREASED WITH LATEST
MODEL RUNS AS UPPER FORCING SHOWN OVER LAST FEW DAYS IS STILL THERE
BUT IS NOW JOINED BY VERY WEAK FRONTOGENESIS...INCREASED DEEP LAYER
MOISTURE...AND A BIT OF INSTABILITY. GFS/NAM/SREFS/ECMWF ALL IN
AGREEMENT ON THIS WAVE AND SOME MEASURABLE QPF AS WELL. THIS WAVE
WILL COME TOGETHER AND MOVE ACROSS SOUTHERN INDIANA DURING THE
OVERNIGHT HOURS INTO THE MORNING. CONSENSUS OF TIMING SHOWS BEST
FORCING OVER THE AREA BETWEEN 9 AND 15Z SO CONFINED HIGHEST POPS TO
THAT TIME WITH LOW CHANCES IN THE NORTHEAST INCREASING TO LIKELIES
ALONG I70 AND SOUTH AND FINALLY CATEGORICAL SNOW IN THE FAR SOUTH.
PRIOR TO THIS WILL SLOWLY RAMP POPS UP WITH ONLY SLIGHT CHANCE PRIOR
TO 6Z AND THEN CHANCES SPREADING NORTHEAST OVER THE AREA FROM 6-9Z.
AS FAR AS PRECIPITATION TYPE IS CONCERNED...MOST MODEL FIELDS ARE
INDICATING ALL SNOW FOR THE ENTIRE AREA...BUT NAM THICKNESSES START
OUT MARGINAL AND RUC SOUNDINGS SHOW POTENTIAL FOR A RAIN SNOW MIX
EARLY IN THE SOUTH. THEREFORE WILL CARRY LOW CHANCES FOR A RAIN SNOW
MIX IN THE SOUTHERN TWO TIERS THROUGH 6Z AND ALL SNOW THEREAFTER.
AS FAR AS AMOUNTS ARE CONCERNED...WITH THE BEST FORCING IN THE SOUTH
WILL GO WITH HIGHEST AMOUNTS THERE. GENERALLY AROUND AN INCH TOTAL
IN THE SOUTH WITH LOCALLY HIGHER AMOUNTS POSSIBLE...HALF AN INCH TO
AN INCH CENTRAL...AND ONLY AROUND A TENTH OF AN INCH IN THE
NORTHWEST IF ANY ACCUMULATION AT ALL AS IT IS FURTHEST FROM THE
FORCING. WHILE HIGHEST AMOUNTS ARE ONLY AROUND AN INCH THE TIMING
WILL BE PROBLEMATIC AS SNOW WILL BEGIN IN THE WEE HOURS OF THE
MORNING AND CONTINUE THROUGH MID MORNING...IMPACTING THE MORNING
COMMUTE. WILL ISSUE AN SPS TO HIGHLIGHT THE TIMING FACTOR.
FOR LOW TEMPERATURES GUIDANCE WAS IN GOOD AGREEMENT SO USED AN
AVERAGE IN THE MID 20S TO LOW 30S.
&&
.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 071800Z TAF ISSUANCE/...
MVFR CEILINGS WITH STRATUS WERE THE RULE OVER MUCH OF THE REGION AT
MIDDAY. THERE ARE SOME SIGNS KBMG MAY BEGINNING TO BREAK OUT OF THE
STRATUS AS THE THE SOUTHERN PORTIONS BEGINS ERODING. OTHER SITES
COULD SCATTER OUT BY LATE AFTERNOON. BUT MODEL SOUNDINGS STILL SHOW
A SOMEWHAT MOIST LAYER RIGHT UNDER A LOW LEVEL INVERSION. SO FOR NOW
WILL KEEP MOST OTHER AREAS BROKEN WITH POSSIBLE EXCEPTION OF KHUF.
EITHER CASE CEILINGS SHOULD IMPROVE TO 25 HND TO 3 THOUSAND BY 22Z
AS SOME LOW LEVEL HEATING OCCURS.
AFTER THE IMPROVEMENT LATE TODAY...ATTENTION SHIFTS TO UPPER TROUGH
OVER THE CENTRAL PLAINS WHICH WILL MOVE OUR WAY LATE TONIGHT. THIS
SYSTEM WILL BRING LIGHT SNOW TO MOST SITES BEGINNING AROUND 08Z AND
POSSIBLE MIXED RAIN/SNOW AT KBMG. THIS WILL CAUSE A LOWERING OF
FLIGHT CONDITIONS WITH SOME AREAS BECOMING IFR. MUCH OF THIS WILL
MOVE OUT BY 15Z AND MVFR CEILINGS WILL BE THE RULE AND SOME SITES
MAY BECOME VFR AFTER 18Z WEDNESDAY. WINDS WILL BE 6 KNOTS OR LESS
THE REST OF TODAY AND TONIGHT AND NORTH 8 TO 10 KNOTS ON WEDNESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....JH
AVIATION...JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
417 AM EST TUE FEB 7 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM
AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
THE HIGH PRESSURE RIDGE WILL BREAK DOWN TONIGHT AS AN UPPER LEVEL
TROUGH MOVES INTO CENTRAL INDIANA. LIGHT SNOW WILL ACCOMPANY THIS
DISTURBANCE BRINGING A DUSTING TO CENTRAL INDIANA LATE TONIGHT AND
TOMORROW MORNING. FURTHER OUT...A BROAD UPPER LEVEL LOW WILL BRING
ANOTHER CHANCE FOR SNOW SHOWERS LATE IN THE WEEK...FOLLOWED BY
MUCH COLDER AIR AND A RETURN TO WINTER.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
PATCHY FOG WILL BE PERSISTENT ONCE AGAIN THIS MORNING...BUT WILL
SLOWLY ERODE AFTER DAYBREAK. NONETHELESS...THERE WILL BE AN
INCREASE IN CLOUDS AHEAD OF THE APPROACHING UPPER LEVEL TROUGH
PROGGED FOR TONIGHT AND TOMORROW MORNING. AS A RESULT...TRIMMED
TODAY/S HIGHS BACK A FEW DEGREES...BUT WAS STILL ABLE TO GO WITH A
MODEL BLEND. HIGHS WILL TOP OFF IN THE UPPER 30S/LOW 40S OVER THE
NORTHERN TWO-THIRDS OF THE FORECAST AREA...AND UPPER 40S OVER THE
SOUTHERN THIRD.
CURENTLY...TEMPS ARE IN THE LOW 30S NORTH OF I-70 WHERE STRATUS
DECK IS HELPING TO DECREASE RADIATIONAL COOLING. FURTHER SOUTH...
TEMPS HAVE FALLEN INTO THE MID TO UPPER 20S WITH SOME REPORTS OF
FREEZING FOG.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS AN UPPER LEVEL TROUGH PROGGED
FOR TONIGHT AND TOMORROW MORNING.
GEM/GFS/NAM ARE IN GOOD AGREEMENT ON TIMING AND TRACK OF LOW. THE
BULK OF PRECIP WILL NOT MOVE IN UNTIL AFTER WED 06Z...ALTHOUGH
THERE WILL BE A SLIGHT CHANCE FOR SOME RAIN/SNOW MIXTURE OVER THE
SOUTH AND SNOW TO THE NORTH BEFORE THAT. BY THE TIME THE BEST
MOISTURE MOVES IN...TEMPS WILL HAVE FALLEN ENOUGH FOR PRECIP TO BE
IN THE FORM OF SNOW ACROSS ALL OF CENTRAL INDIANA. THIS WILL BE A
QUICK DISTURBANCE AND OUT OF THE AREA BY LATE MORNING TOMORROW. IT
WILL RESULT IN A QUICK DUSTING OF SNOW THOUGH...WITH AMOUNTS
RANGING FROM 2 TO 4 TENTHS OF AN INCH. AFTER THAT...MORE ZONAL
FLOW WILL RETURN...AND THE REMAINDER OF THE SHORT TERM WILL BE DRY.
TEMPS...GENERALLY WENT WITH A MODEL BLEND AND CAME UP WITH NUMBERS
CLOSE TO NORMAL FOR THIS TIME OF YEAR. HIGHS WILL TOP OFF IN THE
MID TO UPPER 30S WITH LOWS IN THE 20S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MUCH COLDER WEATHER ANTICIPATED FOR THE EXTENDED AS STRONG POLAR
VORTEX NEAR JAMES BAY DRIFTS SOUTHEAST INTO NORTHERN NEW ENGLAND
THROUGH THE PERIOD. THIS WILL RESULT IN AN AMPLIFICATION OF DEEP
UPPER TROUGHING OVER THE EASTERN PART OF THE COUNTRY OVER THE
WEEKEND.
INCREASING CHANCES FOR SNOW SHOWERS ON FRIDAY AS A COLD FRONT
QUICKLY MOVES THROUGH THE REGION. STRONG COLD ADVECTION IN THE WAKE
OF THIS BOUNDARY WILL USHER IN AN ARCTIC AIRMASS WITH HIGH TEMPS
FALLING BACK INTO THE UPPER 20S AND LOWER 30S FOR THE WEEKEND. LOW
LEVEL WIND FIELDS SHIFT TO A N/NW DIRECTION FOR FRIDAY NIGHT SETTING
THE STAGE FOR FAVORABLE BOUNDARY LAYER CONDITIONS FOR SCATTERED LAKE
EFFECT SNOW SHOWERS OFF LAKE MICHIGAN TO WORK INTO THE NORTHERN
PORTIONS OF THE FORECAST AREA. WILL MAINTAIN CHANCES FOR SNOW
SHOWERS FRIDAY NIGHT AS A RESULT. BACKING OF LOW LEVEL WINDS
SATURDAY COMBINED WITH THE ARRIVAL OF LARGE HIGH PRESSURE WILL END
PRECIP WITH DRY COLD AIRMASS PRESENT FOR THE WEEKEND. GREATER
UNCERTAINTY IN THE FORECAST DEVELOPS BY MONDAY AS THE TROUGH PULLS
AWAY TO THE EAST AND RETURN FLOW ESTABLISHES ON THE BACK SIDE OF THE
DEPARTING HIGH. BOTH ECMWF AND OP GFS HAVE A WEAK DISTURBANCE ALOFT
PASSING THROUGH THE FLOW ON MONDAY BRINGING LOW CHANCES FOR RAIN
AND/OR SNOW. TEMPS WILL MODERATE ON MONDAY BUT STILL REMAIN AT OR
JUST BELOW NORMAL IN THE MID AND UPPER 30S.
&&
.AVIATION /DISCUSSION FOR THE 070900Z TAF UPDATE/...
MADE SOME ADJUSTMENTS AT KIND AND KLAF BASED ON CURRENT OBS. CIGS
RUNNING BETWEEN 600-1200FT SHOULD GRADUALLY DROP TO CLOSER TO 600FT
PRIOR TO DAYBREAK AS LOWER CIGS WITHIN THE STRATUS DECK SAG INTO THE
FORECAST AREA FROM THE NORTH. KHUF REMAINS JUST SOUTH OF THE DECK AT
THIS POINT...BUT RECENT SATELLITE TRENDS SUGGESTING DECK MAY EXPAND
INTO KHUF WITHIN THE NEXT TWO HOURS. VLIFR VISIBILITIES REMAIN AN
ISSUE ONLY AT KBMG. WILL CONTINUE TO MONITOR TRENDS AND ADJUST
ACCORDINGLY THROUGH THE REMAINDER OF THE OVERNIGHT.
06Z DISCUSSION FOLLOWS.
IFR EXPECTED AT ALL SITES AT LEAST BRIEFLY THROUGH MID MORNING.
STRATUS DESK HAS ADVECTED/EXPANDED INTO LAF/IND/HUF...AND RUC PROGS
SUGGEST IT WILL ADVECT INTO BMG AROUND 10Z. DECK SHOULD LIFT/ERODE
BY MID MORNING...WITH ONLY SOME CU AND HIGH CLOUDS TOMORROW. CLOUD
IS MOSTLY MVFR ON ITS FRINGES...WITH EXCEPTION OF EASTERN EDGE NEAR
IND. LOW CONFIDENCE IN EXACTLY HOW LOW STRATUS WILL GET AND AT WHAT
TIMES...BUT CLIMATOLOGY WOULD SUGGEST STRATUS WOULD BE AT ITS LOWEST
NEAR AND JUST AFTER DAYBREAK.
INTRODUCED MIDLEVEL CLOUD TOMORROW EVENING IN ADVANCE OF NEXT SYSTEM.
WINDS WILL BE LIGHT TO CALM...BECOMING NORTHERLY AFTER MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...NIELD/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
326 AM EST TUE FEB 7 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL GIVE WAY TO AN UPPER WAVE TUESDAY NIGHT THAT
WILL BRING SMALL CHANCES FOR SNOW TO CENTRAL INDIANA INTO
WEDNESDAY MORNING. ANOTHER COUPLE OF WEAK WAVES WILL MOVE THROUGH
EARLY IN THE WEEKEND AND AGAIN ON MONDAY AND BRING MORE SMALL
CHANCES FOR PRECIPITATION. TEMPERATURES WILL ACTUALLY DROP TO NEAR
NORMAL FROM MIDWEEK THROUGH THE WEEKEND WITH BROAD TROUGHING OVER
THE EASTERN PART OF THE COUNTRY.
&&
.NEAR TERM /TONIGHT/...
WITH HIGH PRESSURE SUBSIDENCE OVER THE AREA AND A STRATUS DECK TO
THE WEST WITH WESTERLY LOW LEVEL FLOW OVERNIGHT THINK STRATUS WILL
ADVECT BACK INTO THE NORTHWEST AND OVERSPREAD THE NORTHWESTERN TWO
THIRDS OF THE AREA DURING THE OVERNIGHT HOURS SINCE THERE WILL BE
NOTHING TO STOP IT. WHILE LARGE SCALE MODELS DO NOT DO A GOOD JOB
DEPICTING THIS LOW LEVEL RH FIELDS AND SOUNDINGS FROM THE RUC SHOW
THIS POTENTIAL AND THE RUC DID A MUCH BETTER JOB HANDLING WHAT
HAPPENED THIS MORNING. COULD ALSO SEE SOME PATCHY FOG ACROSS THE
AREA. NOT SURE OF EXTENT OR SPECIFIC LOCATION OF FOG...BUT WITH
RECENT MORNINGS AND FORECAST SOUNDINGS WILL GO AHEAD AND PUT PATCHY
FOG EVERYWHERE. WITH THE INCREASE IN CLOUD COVER THAT THE GFS AND
NAM DON/T HAVE ALSO WENT WITH WARMER LOWS THAN GUIDANCE OVER ALL BUT
THE SOUTHEAST WHERE STRATUS MAY NOT REACH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
FORECAST FOCUS IS ON CLOUD COVER TUESDAY AND POPS WITH TUESDAY
NIGHT/WEDNESDAY SYSTEM. MODELS ARE IN DECENT AGREEMENT AND WILL USE
A CONSENSUS APPROACH FOR THE MOST PART.
AFOREMENTIONED STRATUS MAY ERODE SOME IN THE LATE MORNING TUESDAY
BUT WILL ALSO START TO SEE AN INCREASE IN CLOUDS AS THE NEXT UPPER
WAVE APPROACHES FROM THE NORTHWEST...SO NET RESULT SHOULD BE MOSTLY
CLOUDY SKIES TO EVEN CLOUDY SKIES IN THE NORTHWEST. WITH MORE CLOUD
COVER IN THE NORTH AND CENTRAL WILL ALSO DROP HIGHS THERE FROM
GUIDANCE. THE UPPER WAVE MOVING IN TUESDAY NIGHT PROVIDES ONLY WEAK
TO AT MOST MODERATE UPPER LEVEL FORCING AND THERE IS NOTHING ELSE
HELPING THIS SYSTEM...NO INSTABILITY...NO LOW LEVEL FORCING...AND
LITTLE MOISTURE. THE BEST FORCING STILL APPEARS TO BE MOVING THROUGH
BETWEEN 6 AND 12Z AND THUS KEPT LOW CHANCE POPS GOING THEN WITH
SLIGHT CHANCES FOR 6 HOURS ON EITHER SIDE. SOUNDINGS IN ALL BUT THE
SOUTH LOOK COLD ENOUGH FOR ALL SNOW. WILL START WITH A RAIN SNOW MIX
IN THE SOUTH BEFORE CHANGING OVER TO ALL SNOW. LITTLE TO NO
ACCUMULATION EXPECTED.
BY WEDNESDAY 18Z THE UPPER WAVE HAS MOVED OUT OF THE AREA AND
RIDGING IS MOVING BACK INTO THE AREA FROM THEN ON SO DRY WEATHER
FROM THAT POINT THROUGH THURSDAY. WENT COOLER THAN GUIDANCE
WEDNESDAY WITH COLD ADVECTION OCCURRING.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
OVERALL THE EXTENDED WILL BE A QUIET PERIOD. HOWEVER THERE ARE TWO
SYSTEMS THAT MAY GIVE LOW CHANCES OF PRECIP. ONE PERIOD IS FRIDAY
AFTERNOON AND NIGHT AS COLD FRONT MOVES THROUGH FRIDAY AFTERNOON
FOLLOWED BY AN UPPER TROUGH FRIDAY NIGHT AND SATURDAY. THE GFS STILL
HAS US DRY...BUT THE EUROPEAN AND CANADIAN AS WELL AS CONSALL GIVES
US LOW CHANCES OF PRECIPITATION. TEMPERATURES MAY BE WARM ENOUGH
FOR MIXED PRECIP ACROSS OUR SOUTH FRIDAY AFTERNOON. OTHERWISE...WILL
GO WITH A SLIGHT CHANCE OF SNOW SHOWERS.
THE UPPER TROUGH MOVES ON TO THE EAST OVER THE WEEKEND AND WARM
ADVECTION SETS UP BY MONDAY AHEAD OF THE NEXT SYSTEM. THE GFS
BARELY BRINGS PRECIP INTO OUR NORTHWEST BY 00Z TUESDAY AND THE
EUROPEAN IS EVEN SLOWER. WILL TRIM POPS A LITTLE...BUT KEEP LOW
CHANCES ACROSS OUR WEST BY LATE DAY 7. DID NOT MAKE ANY SIGNIFICANT
CHANGE TO ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 070900Z TAF UPDATE/...
MADE SOME ADJUSTMENTS AT KIND AND KLAF BASED ON CURRENT OBS. CIGS
RUNNING BETWEEN 600-1200FT SHOULD GRADUALLY DROP TO CLOSER TO 600FT
PRIOR TO DAYBREAK AS LOWER CIGS WITHIN THE STRATUS DECK SAG INTO THE
FORECAST AREA FROM THE NORTH. KHUF REMAINS JUST SOUTH OF THE DECK AT
THIS POINT...BUT RECENT SATELLITE TRENDS SUGGESTING DECK MAY EXPAND
INTO KHUF WITHIN THE NEXT TWO HOURS. VLIFR VISIBILITIES REMAIN AN
ISSUE ONLY AT KBMG. WILL CONTINUE TO MONITOR TRENDS AND ADJUST
ACCORDINGLY THROUGH THE REMAINDER OF THE OVERNIGHT.
06Z DISCUSSION FOLLOWS.
IFR EXPECTED AT ALL SITES AT LEAST BRIEFLY THROUGH MID MORNING.
STRATUS DESK HAS ADVECTED/EXPANDED INTO LAF/IND/HUF...AND RUC PROGS
SUGGEST IT WILL ADVECT INTO BMG AROUND 10Z. DECK SHOULD LIFT/ERODE
BY MID MORNING...WITH ONLY SOME CU AND HIGH CLOUDS TOMORROW. CLOUD
IS MOSTLY MVFR ON ITS FRINGES...WITH EXCEPTION OF EASTERN EDGE NEAR
IND. LOW CONFIDENCE IN EXACTLY HOW LOW STRATUS WILL GET AND AT WHAT
TIMES...BUT CLIMATOLOGY WOULD SUGGEST STRATUS WOULD BE AT ITS LOWEST
NEAR AND JUST AFTER DAYBREAK.
INTRODUCED MIDLEVEL CLOUD TOMORROW EVENING IN ADVANCE OF NEXT SYSTEM.
WINDS WILL BE LIGHT TO CALM...BECOMING NORTHERLY AFTER MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP/SMF
SHORT TERM...CP
LONG TERM....JH
AVIATION...NIELD/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1139 PM EST MON FEB 6 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL GIVE WAY TO AN UPPER WAVE TUESDAY NIGHT THAT
WILL BRING SMALL CHANCES FOR SNOW TO CENTRAL INDIANA INTO
WEDNESDAY MORNING. ANOTHER COUPLE OF WEAK WAVES WILL MOVE THROUGH
EARLY IN THE WEEKEND AND AGAIN ON MONDAY AND BRING MORE SMALL
CHANCES FOR PRECIPITATION. TEMPERATURES WILL ACTUALLY DROP TO NEAR
NORMAL FROM MIDWEEK THROUGH THE WEEKEND WITH BROAD TROUGHING OVER
THE EASTERN PART OF THE COUNTRY.
&&
.NEAR TERM /TONIGHT/...
WITH HIGH PRESSURE SUBSIDENCE OVER THE AREA AND A STRATUS DECK TO
THE WEST WITH WESTERLY LOW LEVEL FLOW OVERNIGHT THINK STRATUS WILL
ADVECT BACK INTO THE NORTHWEST AND OVERSPREAD THE NORTHWESTERN TWO
THIRDS OF THE AREA DURING THE OVERNIGHT HOURS SINCE THERE WILL BE
NOTHING TO STOP IT. WHILE LARGE SCALE MODELS DO NOT DO A GOOD JOB
DEPICTING THIS LOW LEVEL RH FIELDS AND SOUNDINGS FROM THE RUC SHOW
THIS POTENTIAL AND THE RUC DID A MUCH BETTER JOB HANDLING WHAT
HAPPENED THIS MORNING. COULD ALSO SEE SOME PATCHY FOG ACROSS THE
AREA. NOT SURE OF EXTENT OR SPECIFIC LOCATION OF FOG...BUT WITH
RECENT MORNINGS AND FORECAST SOUNDINGS WILL GO AHEAD AND PUT PATCHY
FOG EVERYWHERE. WITH THE INCREASE IN CLOUD COVER THAT THE GFS AND
NAM DON/T HAVE ALSO WENT WITH WARMER LOWS THAN GUIDANCE OVER ALL BUT
THE SOUTHEAST WHERE STRATUS MAY NOT REACH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
FORECAST FOCUS IS ON CLOUD COVER TUESDAY AND POPS WITH TUESDAY
NIGHT/WEDNESDAY SYSTEM. MODELS ARE IN DECENT AGREEMENT AND WILL USE
A CONSENSUS APPROACH FOR THE MOST PART.
AFOREMENTIONED STRATUS MAY ERODE SOME IN THE LATE MORNING TUESDAY
BUT WILL ALSO START TO SEE AN INCREASE IN CLOUDS AS THE NEXT UPPER
WAVE APPROACHES FROM THE NORTHWEST...SO NET RESULT SHOULD BE MOSTLY
CLOUDY SKIES TO EVEN CLOUDY SKIES IN THE NORTHWEST. WITH MORE CLOUD
COVER IN THE NORTH AND CENTRAL WILL ALSO DROP HIGHS THERE FROM
GUIDANCE. THE UPPER WAVE MOVING IN TUESDAY NIGHT PROVIDES ONLY WEAK
TO AT MOST MODERATE UPPER LEVEL FORCING AND THERE IS NOTHING ELSE
HELPING THIS SYSTEM...NO INSTABILITY...NO LOW LEVEL FORCING...AND
LITTLE MOISTURE. THE BEST FORCING STILL APPEARS TO BE MOVING THROUGH
BETWEEN 6 AND 12Z AND THUS KEPT LOW CHANCE POPS GOING THEN WITH
SLIGHT CHANCES FOR 6 HOURS ON EITHER SIDE. SOUNDINGS IN ALL BUT THE
SOUTH LOOK COLD ENOUGH FOR ALL SNOW. WILL START WITH A RAIN SNOW MIX
IN THE SOUTH BEFORE CHANGING OVER TO ALL SNOW. LITTLE TO NO
ACCUMULATION EXPECTED.
BY WEDNESDAY 18Z THE UPPER WAVE HAS MOVED OUT OF THE AREA AND
RIDGING IS MOVING BACK INTO THE AREA FROM THEN ON SO DRY WEATHER
FROM THAT POINT THROUGH THURSDAY. WENT COOLER THAN GUIDANCE
WEDNESDAY WITH COLD ADVECTION OCCURRING.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
OVERALL THE EXTENDED WILL BE A QUIET PERIOD. HOWEVER THERE ARE TWO
SYSTEMS THAT MAY GIVE LOW CHANCES OF PRECIP. ONE PERIOD IS FRIDAY
AFTERNOON AND NIGHT AS COLD FRONT MOVES THROUGH FRIDAY AFTERNOON
FOLLOWED BY AN UPPER TROUGH FRIDAY NIGHT AND SATURDAY. THE GFS STILL
HAS US DRY...BUT THE EUROPEAN AND CANADIAN AS WELL AS CONSALL GIVES
US LOW CHANCES OF PRECIPITATION. TEMPERATURES MAY BE WARM ENOUGH
FOR MIXED PRECIP ACROSS OUR SOUTH FRIDAY AFTERNOON. OTHERWISE...WILL
GO WITH A SLIGHT CHANCE OF SNOW SHOWERS.
THE UPPER TROUGH MOVES ON TO THE EAST OVER THE WEEKEND AND WARM
ADVECTION SETS UP BY MONDAY AHEAD OF THE NEXT SYSTEM. THE GFS
BARELY BRINGS PRECIP INTO OUR NORTHWEST BY 00Z TUESDAY AND THE
EUROPEAN IS EVEN SLOWER. WILL TRIM POPS A LITTLE...BUT KEEP LOW
CHANCES ACROSS OUR WEST BY LATE DAY 7. DID NOT MAKE ANY SIGNIFICANT
CHANGE TO ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 07/06Z TAFS/...
IFR EXPECTED AT ALL SITES AT LEAST BRIEFLY THROUGH MID MORNING.
STRATUS DESK HAS ADVECTED/EXPANDED INTO LAF/IND/HUF...AND RUC PROGS
SUGGEST IT WILL ADVECT INTO BMG AROUND 10Z. DECK SHOULD LIFT/ERODE
BY MID MORNING...WITH ONLY SOME CU AND HIGH CLOUDS TOMORROW. CLOUD
IS MOSTLY MVFR ON ITS FRINGES...WITH EXCEPTION OF EASTERN EDGE NEAR
IND. LOW CONFIDENCE IN EXACTLY HOW LOW STRATUS WILL GET AND AT WHAT
TIMES...BUT CLIMATOLOGY WOULD SUGGEST STRATUS WOULD BE AT ITS LOWEST
NEAR AND JUST AFTER DAYBREAK.
INTRODUCED MIDLEVEL CLOUD TOMORROW EVENING IN ADVANCE OF NEXT SYSTEM.
WINDS WILL BE LIGHT TO CALM...BECOMING NORTHERLY AFTER MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP/SMF
SHORT TERM...CP
LONG TERM....JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
620 PM CST WED FEB 8 2012
.AVIATION...
SATL TRENDS INDICATE CLEARING HAS SLOWED OVER SOUTHEAST IA AND
WEST CENTRAL IL WITH LOW VFR AND HIGH MVFR CIGS PERSISTING AT
KBRL AND KMLI. FLOW JUST OFF THE SFC REMAINS N/NWLY PER LATEST
VWP DATA AND THUS A DRIER FLOW AND WILL REMAIN OPTIMISTIC ON LOW
CLOUDS EVENTUALLY EXITING KMLI AND KBRL TERMINALS TNGT. OVRNGT
CLEARING SKIES AND LIGHT WINDS MAY BRING ABOUT SOME FOG AS
CROSSOVER TEMPS ARE BREACHED. VSBYS IN FOG GENERALLY 3-6SM BUT
POTENTIAL TO BE LOCALLY AROUND 1SM IN AREAS OF SOUTHEAST IA INTO
WEST CENTRAL IL WHERE CLEARING DELAYED AND SFC DEWPTS HIGHER.
SFC HIGH WILL SLIDE E/SE OF AREA THU WITH W/SWLY FLOW USHERING IN
MORE LOW CLOUDS WITH MAINLY MVFR CIGS... WHICH CURRENTLY RESIDE
OVER NE INTO FAR SW IA. WINDS W/NW 5-10 KTS WILL BACK TO W/SW AT
3-6 KTS OVRNGT THEN INCREASE IN GENERAL RANGE OF 10-15 KTS LATE AM
THROUGH AFTN ON THU.
&&
.PREV DISCUSSION... /ISSUED 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..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1146 AM CST TUE FEB 7 2012
.UPDATE...
MORNING UPDATE LOWERED POPS OUT OF LIKELY CATEGORY SOUTH.
OPERATIONAL MODELS...HRRR AND ARM-NMM WRF RUNS ALL SUGGEST KEEPING
MEASURABLE PRECIP INTO MO. LATEST RUC SOUNDINGS INDICATE 1-3KM DRY
LAYER SOUTH MAKING THOSE ECHOES SEEM WORSE THAT WHAT IS
OCCURRING...AND EXPECT KS/MO PRECIP UPSTREAM TO SWING TO THE SOUTH.
LOW LEVEL COLD ADVECTION SHOULD ALSO KEEP TEMPS STEADY OR SLOWLY
FALLING INTO THE AFTERNOON.
ALSO UPDATED 18Z TAF DISCUSSION.
&&
.SHORT TERM /TODAY/...
TWO UPPER LEVEL SYSTEMS CONVERGING ON THE AREA TODAY...WITH THE
FIRST CURRENTLY MOVING EAST THROUGH THE CENTRAL PLAINS OF NE/KS AND
THE SECOND SYSTEM DROPPING SOUTHWARD THROUGH THE DAKOTAS/MINNESOTA.
COLD FRONT ASSOCIATED WITH THE NORTHERN SYSTEM ALSO MAKING ITS WAY
INTO THE NORTHWESTERN PORTION OF THE CWA...AND WILL CONTINUE TO
PROGRESS THROUGH ENTIRE CWA THROUGH THE MORNING HOURS. HAVE A DECK
OF LOW CLOUDS MOVING INTO AREAS BEHIND THE FRONT...AND ANOTHER DECK
OF HIGHER CLOUDS ASSOCIATED WITH THE WESTERN SYSTEM. ALREADY GETTING
SOME LIGHT PRECIP OUT OF THE HIGHER DECK OF CLOUDS...JUST NOT
REACHING THE GROUND. HOWEVER ONCE START TO GET THE BETTER SATURATION
IN THE LOWER LEVELS BEHIND THE FRONT...COULD START TO GET SOME
SEEDER FEEDER ACTION WITH WEAK LIFT OVER THE AREA THIS MORNING WHICH
COULD LEAD TO SOME SCATTERED FLURRIES/LIGHT SNOW. OTHERWISE DRY
LAYER BETWEEN THE TWO CLOUD DECKS COULD BE TOO DEEP WHICH WOULD NOT
ALLOW ICE CRYSTAL INTRODUCTION TO THE LOWER DECK WHICH COULD LEAD TO
MORE OF A PATCHY FZDZ SITUATION. HOWEVER WITH TEMPERATURES ALOFT
COOLING QUITE RAPIDLY BEHIND THE FRONT...EXPECT ANY FZDZ TO BE
RELATIVELY SHORT-LIVED BEFORE ANY LIGHT PRECIPITATION MAKING IT TO
THE GROUND WOULD CHANGE OVER TO SNOW. ALSO HAVE SOME STRONGER ARES
OF LIFT WITH DEEPER SATURATION PUSHING INTO THE SOUTHWEST TO SOUTH
CENTRAL COUNTIES TOWARD THE LATE MORNING/EARLY AFTERNOON HOURS.
THEREFORE HAVE SOME CHANCE TO LOW LIKELY POPS FOR THAT AREA FOR SOME
LIGHT SNOW. TEMPERATURES WILL BE NEAR OR SLIGHTLY ABOVE
FREEZING...SO NOT EXPECTING MUCH ACCUMULATION WITH THIS SITUATION
BEING A RELATIVELY LOW QPF/HIGH POP EVENT.
.LONG TERM /TONIGHT THROUGH MONDAY/...
SYSTEM PASSING THROUGH STATE TODAY WILL MOVE RAPIDLY EAST TONIGHT
WITH SOME LINGERING FLURRIES IN THE SOUTH DURING THE EVENING.
OTHERWISE...SUBSIDENCE WILL INCREASE OVERNIGHT AS SURFACE RIDGING
BUILDS INTO THE PLAINS AND THE ASSOCIATED DRYING WILL ALLOW CLOUDS
TO DECREASE FROM NORTH TO SOUTH DURING THE NIGHT. THE REST OF THE
FORECAST THROUGH THE WEEKEND IS ONE WITH LITTLE THREAT OF
PRECIPITATION AS MOISTURE AND BEST FORCING WILL RESIDE ELSEWHERE BUT
GENERALLY NOT OVER IOWA. MAIN ISSUES WILL FOCUS ON TEMPERATURE
CHANGES AS THE THERMAL PROFILE CHANGES DURING THE WEEK. READINGS
LIKELY SIMILAR ON WEDNESDAY WHEN COMPARED TO TODAY AS SIMILAR
AIRMASS REMAINS OVER THE STATE. HOWEVER...SOME MODERATION IS
EXPECTED INTO THURSDAY AS A WEAK THERMAL RIDGE SLIDES INTO THE STATE
AND HAVE WARMED READINGS ABOVE GUIDANCE IN LOCATIONS NOT INFLUENCED
BY THE CURRENT SNOWPACK. HOWEVER...A MUCH STRONGER PUSH OF POLAR
AIR IS SET TO ARRIVE ON FRIDAY AND PERSIST INTO SATURDAY ACROSS THE
STATE. MEDIUM RANGE GUIDANCE HAS FINALLY CAUGHT ONTO THIS COOLER
AIR WITH OUTPUT NOT AS WARM AS PREVIOUS RUNS. HAVE CONTINUED TO
KEEP HIGHS AND LOWS COOLER OF THE SNOW PACK DURING THIS TIME WITH
READINGS HARD PRESSED TO GET OUT OF THE 20S ON FRIDAY OR SATURDAY.
SOME MODERATION IS THEN EXPECTED ON SUNDAY INTO MONDAY AS SOUTHERLY
FLOW INCREASES. THERE IS AN OUTSIDE CHANCE OF SOME SNOWFALL EARLY
IN THE WEEK BUT TIMING OF THE SYSTEM IS SOMEWHAT VAGUE THIS FAR
OUT. HAVE LEFT IN SLIGHT CHANCES ON MONDAY WHICH TENDS TO REFLECT
THE LOW CONFIDENCE AT THIS POINT OF SEEING MUCH PRECIPITATION AT
THIS TIME.
&&
.AVIATION...07/18Z
IFR STRATUS CONTINUES TO AFFECT SE IA WITH WIDESPREAD MVFR
CONDITIONS UPSTREAM ACROSS IA INTO MN AND WI. MODELS INDICATE VERY
GRADUAL IMPROVEMENT NORTH-SOUTH BECOMING VFR 01Z-09Z. OCCASIONAL
FLURRIES OR LIGHT SNOW MAY AFFECT SITES OUTSIDE OF KMCW BUT ANY VSBY
RESTRICTIONS WOULD PRIMARILY BE TO FOG RATHER THAN SNOW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE/AVIATION...SMALL
SHORT TERM...BEERENDS
LONG TERM...COGIL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
844 PM MST WED FEB 8 2012
.UPDATE...
841 PM MST WED FEB 8 2012
JUST COMPLETED ANOTHER UPDATE. WAS SKEPTICAL OF EARLIER MODEL DATA
IN REGARDS TO FOG FORMATION SINCE IT OVERDID IT LAST NIGHT.
HOWEVER...SOME FOG HAS DEVELOPED IN THE SOUTHERN PORTION OF THE
FORECAST AREA. THIS DOES MAKE SENSE WITH AREA SOUNDINGS. LATEST
HRRR CATCHES THIS AREA AND EXPANDS IT NORTHEAST AHEAD OF THE
INCOMING SURFACE TROUGH LINE. THIS MAKES SENSE SO HAVE INSERTED
PATCHY FZFG FROM NOW INTO TOMORROW MORNING.
BULLER
&&
.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...
407 PM MST WED FEB 8 2012
FOR THE 00Z TAFS...LOW STRATUS CONTINUES TO BLANKET THE AREA JUST
EAST OF KGLD AND INCLUDING KMCK. AFTER SUNSET...EXPECT STRATUS TO
REDEVELOP AND MOVE WESTWARD...POSSIBLY AFFECTING KGLD. HAVE
INSERTED TEMPO FOR MVFR CIGS HERE FROM 01-05Z TO ACCOUNT FOR THIS.
WINDS WILL SWITCH TO THE WEST LATE EVENING WHICH WILL ALLOW DRIER
AIR TO WORK ITSELF INTO KGLD WHICH WILL AID TO SCATTER OUT
STRATUS. FOR KMCK...WINDS WILL SWITCH TO WESTERLY AROUND 07-08Z
TIMEFRAME AND SCATTER OUT STRATUS AROUND 10Z OR SO.
AFTERWARDS...MAINLY MID/HIGH CLOUDS AND WESTERLY/NORTHWESTERLY
WINDS THROUGH REST OF THE PERIOD.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
609 PM MST WED FEB 8 2012
.UPDATE...
603 PM MST WED FEB 8 2012
JUST COMPLETED AN UPDATE. CURRENT DEWPOINTS RUNNING HIGHER THAN
WHAT WAS IN THE GRIDS. LATEST HRRR LOOKED TO BE CATCHING THESE THE
BEST AND USED FOR THE UPDATE. LATEST RUC AND ECMWF WHICH CATCHING
THE WINDS WELL TO. WINDS TO WERE MORE TO EAST AND SOUTHEAST TO
SOUTH OF OUR AREA AND ADJUSTED ACCORDINGLY. ALSO PRETTY THICK MID
LEVEL CLOUD COVER AND ALSO STRATUS LOOKS LIKE IT IS MOVING NORTH
AGAIN. SO INCREASED THE CLOUD COVER. BECAUSE OF THE INCREASE IN
DEWPOINTS AND CLOUDS RAISED MINS...MOSTLY IN THE SOUTHEAST HALF TO
TWO THIRDS OF THE AREA.
BULLER
&&
.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...
407 PM MST WED FEB 8 2012
FOR THE 00Z TAFS...LOW STRATUS CONTINUES TO BLANKET THE AREA JUST
EAST OF KGLD AND INCLUDING KMCK. AFTER SUNSET...EXPECT STRATUS TO
REDEVELOP AND MOVE WESTWARD...POSSIBLY AFFECTING KGLD. HAVE
INSERTED TEMPO FOR MVFR CIGS HERE FROM 01-05Z TO ACCOUNT FOR THIS.
WINDS WILL SWITCH TO THE WEST LATE EVENING WHICH WILL ALLOW DRIER
AIR TO WORK ITSELF INTO KGLD WHICH WILL AID TO SCATTER OUT
STRATUS. FOR KMCK...WINDS WILL SWITCH TO WESTERLY AROUND 07-08Z
TIMEFRAME AND SCATTER OUT STRATUS AROUND 10Z OR SO.
AFTERWARDS...MAINLY MID/HIGH CLOUDS AND WESTERLY/NORTHWESTERLY
WINDS THROUGH REST OF THE PERIOD.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
407 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...
407 PM MST WED FEB 8 2012
FOR THE 00Z TAFS...LOW STRATUS CONTINUES TO BLANKET THE AREA JUST
EAST OF KGLD AND INCLUDING KMCK. AFTER SUNSET...EXPECT STRATUS TO
REDEVELOP AND MOVE WESTWARD...POSSIBLY AFFECTING KGLD. HAVE
INSERTED TEMPO FOR MVFR CIGS HERE FROM 01-05Z TO ACCOUNT FOR THIS.
WINDS WILL SWITCH TO THE WEST LATE EVENING WHICH WILL ALLOW DRIER
AIR TO WORK ITSELF INTO KGLD WHICH WILL AID TO SCATTER OUT
STRATUS. FOR KMCK...WINDS WILL SWITCH TO WESTERLY AROUND 07-08Z
TIMEFRAME AND SCATTER OUT STRATUS AROUND 10Z OR SO.
AFTERWARDS...MAINLY MID/HIGH CLOUDS AND WESTERLY/NORTHWESTERLY
WINDS THROUGH REST OF THE PERIOD.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1215 PM CST TUE FEB 7 2012
.UPDATE...
ISSUED AT 1210 PM CST TUE FEB 7 2012
SNOW CONTINUES TO TAPER OFF WEST AND NORTH OF DODGE CITY. HAVE
THEREFORE REMOVED SEVERAL MORE COUNTIES FROM THE WINTER WEATHER
ADVISORY. THE NEW RUC40 AND HRRR CONTINUES TO KEEP THE BETTER
FORCING SOUTH AND SOUTHEAST OF DODGE FOR THE NEXT FEW HOURS BUT
EVEN HERE THE TREND WILL BE A DECREASING TREND BASED ON THE
MOVEMENT OF THE MID LEVEL BAROCLINIC ZONE AND 300MB JET. ADDITION
SNOWFALL IN THE ADVISORY AREA IS EXPECTED TO AVERAGE ONE INCH OR
LESS BETWEEN NOON AND 4 PM. GUSTY WINDS COMBINED WITH THIS
EXPECTED SNOWFALL WILL CONTINUE TO REDUCE VISIBILITIES DUE TO
BLOWING/DRIFTING SNOW.
UPDATE ISSUED AT 1006 AM CST TUE FEB 7 2012
AREA MOST FAVORABLE FOR SNOW TO CONTINUE THROUGH THE EARLY
AFTERNOON WILL BE EAST OF MEADE TO DODGE CITY TO NEAR NESS CITY
LINE GIVEN THE LOCATION OF THE LEFT EXIT REGION OF THE 300MB JET
AT 12Z AND MOISTURE AT 850-700MB AHEAD OF THE 700MB BAROCLINIC
ZONE. SNOW AMOUNTS STILL APPEAR TO BE ON TRACK WITH GENERAL
AMOUNTS OF AROUND 2 INCHES IN THE ADVISORY AREA AND A FEW LOCALLY
HIGHER AMOUNTS POSSIBLE. AS A RESULT WILL CONTINUE THE WINTER
WEATHER ADVISORY IN THESE AREAS. FURTHER WEST CANCELED THE WINTER
WEATHER ADVISORY ALTHOUGH A FEW FLURRIES WILL STILL BE POSSIBLE
FOR THE NEXT COUPLE OF HOURS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 337 AM CST TUE FEB 7 2012
WATER VAPOR IMAGERY IS SHOWING THAT THE UPPER LOW THAT WAS SPINNING
OVER WESTERN COLORADO 24 HOURS AGO HAD OPENED UP AND WAS OVER THE
EASTERN PLAINS OF COLORADO EARLY THIS MORNING. THE UPPER AIR
ANALYSIS SHOWED AN 80 KNOT JET MAX OVER CENTRAL NEW MEXICO. CLOUD
TOPS WERE COOLING OVER FAR WESTERN KANSAS AS THE UPPER LEVEL
FORCING APPROACHED THE AREA. A COLD FRONT WAS ALSO MOVING SOUTH
ACROSS THE HIGH PLAINS AND WAS THROUGH FAR SOUTHWEST KANSAS AND
POISED TO MOVE THROUGH SOUTH CENTRAL KANSAS EARLY THIS MORNING.
THE RADAR MOSAIC WAS SHOWING AREAS OF LIGHT SNOW CONTINUING TO
DEVELOP AND EXPAND ACROSS THE REGION.
THE GOING FORECAST FOR THE DEVELOPING WINTER WEATHER SEEMS TO BE
ON TRACK AND ONLY REQUIRED SOME MINOR TWEAKS. THE 00Z MODEL RUNS
WERE IN PRETTY GOOD AGREEMENT WITH THE UPPER FEATURES. MODEL QPF
AND SNOW FORECAST AMOUNTS ARE POINTING AT GENERAL 1 TO 3 INCH
SNOWFALL ACCUMULATIONS WITH SOME LOCALLY HEAVIER AMOUNTS OF 4-5
INCHES POSSIBLE. HARD TO TELL EXACTLY HOW MUCH WILL FALL GIVEN THE
PROGRESSIVE NATURE OF THIS SYSTEM. THE MODELS SHOW THE BULK OF THE
UPWARD VERTICAL MOTION OCCURRING DURING THE 12Z-18Z TIMEFRAME AND
TIME SECTIONS SHOW THE UPWARD MOTION FOCUSED IN THE DENDRITIC
GROWTH LAYER. GIVEN THE COLD AIRMASS ACCOMPANYING THIS SYSTEM,
LIQUID/SNOW RATIOS SHOULD BE HIGHER THAN 10:1 AS WELL AND POSSIBLY
CLOSER TO 15:1. HAVE BUMPED UP POPS AND SNOWFALL ACCUMULATIONS
JUST A BIT ESPECIALLY IN THE AREA WHERE THE CURRENT WINTER WEATHER
ADVISORY IS IN EFFECT. WINDS ARE ALREADY STARTING TO PICK UP
BEHIND THE FRONT SO SOME BLOWING AND DRIFTING SNOW CAN ALSO BE
EXPECTED. THE SNOW SHOULD BE TAPERING OFF RAPIDLY FROM WEST TO
EAST ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS FROM LATE MORNING
THROUGH MID AFTERNOON AND SHOULD BE EAST OF THE AREA BY SUNSET.
HIGH PRESSURE BUILDING SOUTH OUT OF CANADA TODAY WILL BE MOVING
DOWN OVER KANSAS TONIGHT SO EXPECT SKIES TO BE CLEARING ACROSS ALL
THE AREA BY THIS EVENING WITH LIGHT WINDS BY TUESDAY MORNING. MOS
GUIDANCE HAS TEMPERATURES INTO THE UPPER SINGLE DIGITS AND LOWER
TEENS OVER MOST OF THE AREA AND HAVE UNDERCUT BY A FEW DEGREES IN
PLACES. LOWS MAY WIND UP BEING EVEN COLDER.
WEDNESDAY SHOULD BE MOSTLY SUNNY BUT TEMPERATURES WILL NOT LIKELY
RISE MUCH ABOVE FREEZING GIVEN THE COLD START TO THE DAY AND SOME
LINGERING SNOW COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 337 AM CST TUE FEB 7 2012
FAIRLY TRANQUIL WEATHER CAN BE EXPECTED THURSDAY AND FRIDAY IN THE
WAKE OF THE UPPER-LEVEL SYSTEM THAT WILL PASS TUESDAY. THE MAIN
FORECAST CHALLENGE IS THE AMOUNT OF SNOW COVER AND ITS EFFECT ON
TEMPERATURES. GIVEN THAT VERY COLD TEMPERATURES ARE EXPECTED TUESDAY
NIGHT WITH CLEAR SKIES AND SNOW COVER, THE SNOW WILL BE SLOW TO MELT
WEDNESDAY GIVEN THE FROZEN GROUND. THEREFORE, IT SEEMS REASONABLE TO
EXPECT THAT SOME SNOW COVER WILL LINGER IN PLACES INTO THURSDAY,
ESPECIALLY FROM DODGE CITY SOUTHWARD. THEREFORE, MAXIMUM
TEMPERATURES WERE LOWERED A FEW DEGREES IN THIS AREA FOR THURSDAY.
A POLAR VORTEX WILL BE SWINGING SOUTHEASTWARD OUT OF CANADA INTO THE
GREAT LAKES REGION BY THURSDAY NIGHT AND FRIDAY. THE BRUNT OF THE
COLD AIR WITH THIS SYSTEM WILL STAY WELL TO OUR NORTHEAST. BUT THIS
GLANCING SHOT OF COOLER AIR SHOULD PREVENT ANY MAJOR WARMUP EVEN
AFTER THE SNOW MELTS (ASSUMING IT DOES MELT BY THEN).
THE NEXT MAJOR FORECAST CHALLENGE IS THE AMPLITUDE AND TIMING OF THE
NEXT UPPER-LEVEL TROUGH OVER THE WEEKEND AND INTO EARLY NEXT WEEK.
DESPITE THE MODEL DIFFERENCES, THE COMMON THEME IS THAT SOMETIME
DURING THIS PERIOD THERE WILL BE A WARM ADVECTION PATTERN DEVELOPING
IN THE WAKE OF A LOW-LEVEL COLD SURGE AS THE UPPER-LEVEL TROUGH
APPROACHES. THE CENTRAL REGION PRECIPITATION PROBABILITY GRIDS LOOK
REASONABLE, WITH 20-30% CHANCES BY SATURDAY NIGHT INTO SUNDAY NIGHT.
HOWEVER, MAXIMUM TEMPERATURES MAY BE COLDER FOR THE SUNDAY TO
TUESDAY TIME FRAME THAN WHAT IS CURRENTLY DEPICTED IN THE GRIDS,
ESPECIALLY IF WE DO RECEIVE SOME SNOW. ALSO, DIURNAL RANGES MAY BE
TOO LARGE GIVEN A CLOUDY REGIME. BUT GIVEN THE UNCERTAINTY, IT WAS
DECIDED UPON OFFICE COLLABORATION THAT THE CURRENT TREND OF COOLING
TEMPERATURES DOWN GRADUALLY WAS SUFFICIENT IN LIEU OF A SUDDEN,
MAJOR OVERHAUL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1115 AM CST TUE FEB 7 2012
AS AN UPPER LEVEL TROUGH AND MID LEVEL BAROCLINIC ZONE MOVES EAST
OF THE AREA EARLY THIS AFTERNOON THE MID LEVEL MOISTURE WILL
CONTINUE TO DECREASE. LOW LEVEL MOISTURE HOWEVER WILL PERSIST
BASED ON THE 12Z NAM BURF SOUNDINGS WHICH INDICATES THE LOW LEVEL
MOISTURE WILL LINGER THROUGH MUCH OF THE OVERNIGHT PERIOD. GFS
HOWEVER SUGGESTS LESS MOISTURE OVERNIGHT BUT GIVEN THE 17Z VISIBLE
SATELLITE IMAGE AND SURFACE OBSERVATONS ACROSS NORTHWEST KANSAS
AND EASTERN COLORADO AM CURRENTLY LEANING TOWARDS THE MORE
PESIMISTIC NAM IN KEEPING LOW IFR CLOUDS AROUND LONGER TONIGHT.
THE MIXED LAYER WINDS, WHICH DID A GOOD JOB WITH THE VERY WINDY
CONDITIONS EARLIER TODAY, DECREASE THROUGH THE REMAINDER OF THE
AFTERNOON AND BECOME LIGHT OVERNIGHT AS AN AREA OF HIGH PRESSURE
AT THE SURFACE BUILDS INTO CENTRAL AND WESTERN KANSAS. -RB
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 14 34 19 40 / 0 0 0 0
GCK 13 36 18 42 / 0 0 0 0
EHA 16 41 22 43 / 0 0 0 0
LBL 16 38 22 41 / 0 0 0 0
HYS 13 31 17 44 / 0 0 0 0
P28 21 35 22 43 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR KSZ064-
065-078>080-088-089.
&&
$$
UPDATE...18
SHORT TERM...02
LONG TERM....24
AVIATION...18
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1214 PM EST TUE FEB 07 2012
...Updated Aviation Discussion...
.Forecast Update...
Just making a few minor adjustments to the ongoing forecast, which
is pretty much on track. Low strato-cu will continue to spill
southeast into our far northern/northeastern counties. Don`t really
see this eroding on the southern edge as it did yesterday, so
although portions of s-central IN and n-central KY have sunny skies
now, we should see mostly cloudy skies by this afternoon. Just
beefed up cloud cover a bit in the grids, but overall temps/etc. on
track.
Upper disturbance approaching from the west won`t affect our CWA
until after midnight most likely. Will address that with afternoon
AFD.
Updated web forecast. No other changes made.
&&
.Short Term (Today - Wednesday)...
High pressure in place along with weak ridging aloft will keep
things dry today, although will have to deal with patchy
fog/freezing fog potential again through the morning hours. IR
satellite imagery currently shows a batch of low stratus across the
Great Lakes region to as far south as the I 74 corridor over central
and southern Indiana. HRRR has been consistent in showing these
clouds marching steadily southeast through the pre-dawn hours,
arriving near the Ohio River just after dawn. Therefore, skies
should clear in most spots with calm winds and subsident airmass.
This will lead to patchy fog formation, some of which will likely be
dense around dawn. Most likely areas will be in valleys and near
rivers and streams. With temperatures below freezing in most spots
will have to watch for slick spots. Will spend the rest of the
morning monitoring obs and issuing SPS or headline products if need
be. Right now, the only real indication of fog is over the Lake
Cumberland region.
Above mentioned status deck will likely scatter out over southern
Indiana this morning with upper level clouds beginning stream
overhead through the day. With low temperatures cooler than expected
this morning, have lowered highs a bit for this afternoon. Southern
Indiana will likely not make it out of the upper 40s with lower
level cloud cover this morning. Elsewhere, lower 50s can be expected
with mid 50s possible south.
The next weather making system will arrive after Midnight tonight as
an upper level impulse quickly ejects across the plains, absorbing
an upper low currently over NE Colorado. What may initially start
out as rain or a rain/snow mix across southern Indiana and central
Kentucky should quickly change over to snow as wet bulbing occurs
with low level saturation. Surface temperatures may stay just above
freezing in a few locations however warm layer at the surface will
be very shallow and should still support mostly snow. South of a
Bowling Green to Lake Cumberland line, precipitation type is more in
question and could end up being more rain and possibly a rain/snow
mix by dawn.
Best chances for precipitation, whether it be rain or snow, will be
from 3 AM EST to 8 AM EST early Wednesday. Will have to watch for a
moderate band of snow setting up anywhere from along and south of
the Ohio River to along and north of a Bowling Green to Lexington
line between 3 AM EST and dawn. This will occur just ahead of sharp
shortwave trough axis with frontogenesis coinciding with the left
exit region of an intensifying 100 to 120 knot upper level jet.
Models continue to indicate low amounts of QPF with this quick
hitting system, although have steadily increased amounts. Will have
to watch trends over the next 24 hours as banding does appear
possible with this setup and could produce a narrow swath of higher
QPF. That being said, ground and road temperatures should be well
above freezing with recent warm weather so do not expect any real
accumulation on these surfaces. Could see a dusting on grassy and
elevated surfaces by the daylight hours on Wednesday.
Upper level features quickly depart to the east by midday Wednesday,
however plentiful low level moisture between 1000-850 mb suggests
some flurries or sprinkles will be possible. Models are suggesting a
warm up to the low and mid 40s during the day however with overcast
skies expected, have a feeling temperatures will have trouble
getting out of the 30s. Therefore, will call for precipitation type
mostly in light snow or flurry category as any warm layer will be
confined to the surface and low level lapse rates will quickly
steepen. Could even see a few snow bursts through the day on
Wednesday as low levels edge toward a low degree of convective
instability. Again, expecting no real accumulations. Flurries or
sprinkles will linger through the day on Wednesday, along with
mostly cloudy skies.
.Long Term (Wednesday night - Monday)...
Wednesday night through Thursday night...
Main upper impulse will be exiting the area, but still expect some
residual low-level moisture to lingering Wednesday evening.
Subsidence and very shallow moist layer weigh against any precip so
no POPs in the forecast, but moisture and NW flow are sufficient
reason to hold onto a few early evening snow flurries in the eastern
tier.
Cold and dry high pressure on Thursday, with a broad, weak upper
trof overhead. MOS guidance is generally too warm in a shallow cold
air mass like this, so this forecast is more in line with the raw
model temps, with highs in the lower 40s in spite of full sunshine.
Clear and chilly Thursday night, but lows in the mid-upper 20s are
right in line with climo.
Friday through Monday...
Low-confidence forecast here as the models start to diverge. ECMWF
and GFS both drag some combination of a Clipper and/or cold front
across the Ohio Valley Friday night. ECMWF is trending more bullish
with southern-stream phasing and associated moisture. Will not jump
on this solution just yet but it bears watching. For now will go
with a slight chance for snow showers Fri night, mainly east of
I-65.
Cold high pressure plunges south from Canada for the weekend. Below
normal temperatures are a slam dunk but the question remains, how
much below normal? Coldest 850mb temps will be Saturday, when GFS
gets as cold as -14C. Current forecast max temps in the mid 30s may
be a bit too warm. Coldest night is Sat night, with lower 20s
across most locations. Not going for the quick rebound indicated by
extended GFS MOS on Sunday, given the cold start and model bias of
moving a high pressure ridge east too quickly. Expect highs in the
mid/upper 30s even with the thermal trof to our east.
Another southern stream system will affect the Ohio Valley early
next week, but model discrepancies are too large to jump on any one
solution just yet. Will keep Monday dry for now, as the quicker
ECMWF is also the less bullish model as far as QPF. Temps recover to
the high side of normal by Monday.
&&
.Aviation (18Z TAF Issuance)...
Over the next couple of hours, the main issue will be the strato-cu
clouds pushing south into northern KY, particularly affecting LEX.
Looks like these clouds are eroding somewhat, but will go ahead and
include a few hours of MVFR SCT-BKN clouds in at LEX and maybe SDF.
Otherwise, mid-high level clouds will push in from the west later
this afternoon as a weak upper disturbance over the Central Plains
arrives tonight. Light precipitation will increase from west to east
overnight, most likely affect BWG first by 06z, then SDF by 09z-ish,
and then LEX by approximately 11z. The more persistent precipitation
will arrive 2-3 hours after onset, with possibly MVFR CIGs and VSBYs
occurring along with it.
Moisture moves out of the area rapidly, and think by the end of this
TAF period, BWG will be drying out, and possibly SDF by then, too.
For precip type, looks like onset may be just -SN, but a -RASN mix
is possible at BWG, too. Light snow will be the dominate type at SDF
and LEX, and will push back the onset 1-2 hours at these locations
in the TAFs. Otherwise no real big changes. For winds, expect
north-northwest winds over the area throughout the TAF period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AL
Short Term.......BJS
Long Term........RAS
Aviation.........AL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1039 AM EST TUE FEB 07 2012
...Forecast Update...
Just making a few minor adjustments to the ongoing forecast, which
is pretty much on track. Low strato-cu will continue to spill
southeast into our far northern/northeastern counties. Don`t really
see this eroding on the southern edge as it did yesterday, so
although portions of s-central IN and n-central KY have sunny skies
now, we should see mostly cloudy skies by this afternoon. Just
beefed up cloud cover a bit in the grids, but overall temps/etc. on
track.
Upper disturbance approaching from the west won`t affect our CWA
until after midnight most likely. Will address that with afternoon
AFD.
Updated web forecast. No other changes made.
&&
.Short Term (Today - Wednesday)...
High pressure in place along with weak ridging aloft will keep
things dry today, although will have to deal with patchy
fog/freezing fog potential again through the morning hours. IR
satellite imagery currently shows a batch of low stratus across the
Great Lakes region to as far south as the I 74 corridor over central
and southern Indiana. HRRR has been consistent in showing these
clouds marching steadily southeast through the pre-dawn hours,
arriving near the Ohio River just after dawn. Therefore, skies
should clear in most spots with calm winds and subsident airmass.
This will lead to patchy fog formation, some of which will likely be
dense around dawn. Most likely areas will be in valleys and near
rivers and streams. With temperatures below freezing in most spots
will have to watch for slick spots. Will spend the rest of the
morning monitoring obs and issuing SPS or headline products if need
be. Right now, the only real indication of fog is over the Lake
Cumberland region.
Above mentioned status deck will likely scatter out over southern
Indiana this morning with upper level clouds beginning stream
overhead through the day. With low temperatures cooler than expected
this morning, have lowered highs a bit for this afternoon. Southern
Indiana will likely not make it out of the upper 40s with lower
level cloud cover this morning. Elsewhere, lower 50s can be expected
with mid 50s possible south.
The next weather making system will arrive after Midnight tonight as
an upper level impulse quickly ejects across the plains, absorbing
an upper low currently over NE Colorado. What may initially start
out as rain or a rain/snow mix across southern Indiana and central
Kentucky should quickly change over to snow as wet bulbing occurs
with low level saturation. Surface temperatures may stay just above
freezing in a few locations however warm layer at the surface will
be very shallow and should still support mostly snow. South of a
Bowling Green to Lake Cumberland line, precipitation type is more in
question and could end up being more rain and possibly a rain/snow
mix by dawn.
Best chances for precipitation, whether it be rain or snow, will be
from 3 AM EST to 8 AM EST early Wednesday. Will have to watch for a
moderate band of snow setting up anywhere from along and south of
the Ohio River to along and north of a Bowling Green to Lexington
line between 3 AM EST and dawn. This will occur just ahead of sharp
shortwave trough axis with frontogenesis coinciding with the left
exit region of an intensifying 100 to 120 knot upper level jet.
Models continue to indicate low amounts of QPF with this quick
hitting system, although have steadily increased amounts. Will have
to watch trends over the next 24 hours as banding does appear
possible with this setup and could produce a narrow swath of higher
QPF. That being said, ground and road temperatures should be well
above freezing with recent warm weather so do not expect any real
accumulation on these surfaces. Could see a dusting on grassy and
elevated surfaces by the daylight hours on Wednesday.
Upper level features quickly depart to the east by midday Wednesday,
however plentiful low level moisture between 1000-850 mb suggests
some flurries or sprinkles will be possible. Models are suggesting a
warm up to the low and mid 40s during the day however with overcast
skies expected, have a feeling temperatures will have trouble
getting out of the 30s. Therefore, will call for precipitation type
mostly in light snow or flurry category as any warm layer will be
confined to the surface and low level lapse rates will quickly
steepen. Could even see a few snow bursts through the day on
Wednesday as low levels edge toward a low degree of convective
instability. Again, expecting no real accumulations. Flurries or
sprinkles will linger through the day on Wednesday, along with
mostly cloudy skies.
.Long Term (Wednesday night - Monday)...
Wednesday night through Thursday night...
Main upper impulse will be exiting the area, but still expect some
residual low-level moisture to lingering Wednesday evening.
Subsidence and very shallow moist layer weigh against any precip so
no POPs in the forecast, but moisture and NW flow are sufficient
reason to hold onto a few early evening snow flurries in the eastern
tier.
Cold and dry high pressure on Thursday, with a broad, weak upper
trof overhead. MOS guidance is generally too warm in a shallow cold
air mass like this, so this forecast is more in line with the raw
model temps, with highs in the lower 40s in spite of full sunshine.
Clear and chilly Thursday night, but lows in the mid-upper 20s are
right in line with climo.
Friday through Monday...
Low-confidence forecast here as the models start to diverge. ECMWF
and GFS both drag some combination of a Clipper and/or cold front
across the Ohio Valley Friday night. ECMWF is trending more bullish
with southern-stream phasing and associated moisture. Will not jump
on this solution just yet but it bears watching. For now will go
with a slight chance for snow showers Fri night, mainly east of
I-65.
Cold high pressure plunges south from Canada for the weekend. Below
normal temperatures are a slam dunk but the question remains, how
much below normal? Coldest 850mb temps will be Saturday, when GFS
gets as cold as -14C. Current forecast max temps in the mid 30s may
be a bit too warm. Coldest night is Sat night, with lower 20s
across most locations. Not going for the quick rebound indicated by
extended GFS MOS on Sunday, given the cold start and model bias of
moving a high pressure ridge east too quickly. Expect highs in the
mid/upper 30s even with the thermal trof to our east.
Another southern stream system will affect the Ohio Valley early
next week, but model discrepancies are too large to jump on any one
solution just yet. Will keep Monday dry for now, as the quicker
ECMWF is also the less bullish model as far as QPF. Temps recover to
the high side of normal by Monday.
&&
.Aviation (12Z TAF Issuance)...
Surface high pressure will remain in control at the surface and
aloft through most of today before conditions deteriorate after
midnight as light snow overspreads much of the region. Will have to
deal with some patchy fog early this morning, with BWG having the
most persistent MVFR vis with temporary IFR possible. SDF and LEX
are more likely to stay VFR. Otherwise, expect increasing upper
level sky cover through the day with generally northwest winds
around 5 mph.
After Midnight, light snow is expected to overspread SDF/LEX with
visibilities around the MVFR/VFR threshold and ceilings solidly in
the MVFR range. Further south, BWG should expect mostly rain or a
rain/snow mix with MVFR ceilings.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AL
Short Term.......BJS
Long Term........RAS
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
604 AM EST TUE FEB 07 2012
.Short Term (Today - Wednesday)...
High pressure in place along with weak ridging aloft will keep
things dry today, although will have to deal with patchy
fog/freezing fog potential again through the morning hours. IR
satellite imagery currently shows a batch of low stratus across the
Great Lakes region to as far south as the I 74 corridor over central
and southern Indiana. HRRR has been consistent in showing these
clouds marching steadily southeast through the pre-dawn hours,
arriving near the Ohio River just after dawn. Therefore, skies
should clear in most spots with calm winds and subsident airmass.
This will lead to patchy fog formation, some of which will likely be
dense around dawn. Most likely areas will be in valleys and near
rivers and streams. With temperatures below freezing in most spots
will have to watch for slick spots. Will spend the rest of the
morning monitoring obs and issuing SPS or headline products if need
be. Right now, the only real indication of fog is over the Lake
Cumberland region.
Above mentioned status deck will likely scatter out over southern
Indiana this morning with upper level clouds beginning stream
overhead through the day. With low temperatures cooler than expected
this morning, have lowered highs a bit for this afternoon. Southern
Indiana will likely not make it out of the upper 40s with lower
level cloud cover this morning. Elsewhere, lower 50s can be expected
with mid 50s possible south.
The next weather making system will arrive after Midnight tonight as
an upper level impulse quickly ejects across the plains, absorbing
an upper low currently over NE Colorado. What may initially start
out as rain or a rain/snow mix across southern Indiana and central
Kentucky should quickly change over to snow as wet bulbing occurs
with low level saturation. Surface temperatures may stay just above
freezing in a few locations however warm layer at the surface will
be very shallow and should still support mostly snow. South of a
Bowling Green to Lake Cumberland line, precipitation type is more in
question and could end up being more rain and possibly a rain/snow
mix by dawn.
Best chances for precipitation, whether it be rain or snow, will be
from 3 AM EST to 8 AM EST early Wednesday. Will have to watch for a
moderate band of snow setting up anywhere from along and south of
the Ohio River to along and north of a Bowling Green to Lexington
line between 3 AM EST and dawn. This will occur just ahead of sharp
shortwave trough axis with frontogenesis coinciding with the left
exit region of an intensifying 100 to 120 knot upper level jet.
Models continue to indicate low amounts of QPF with this quick
hitting system, although have steadily increased amounts. Will have
to watch trends over the next 24 hours as banding does appear
possible with this setup and could produce a narrow swath of higher
QPF. That being said, ground and road temperatures should be well
above freezing with recent warm weather so do not expect any real
accumulation on these surfaces. Could see a dusting on grassy and
elevated surfaces by the daylight hours on Wednesday.
Upper level features quickly depart to the east by midday Wednesday,
however plentiful low level moisture between 1000-850 mb suggests
some flurries or sprinkles will be possible. Models are suggesting a
warm up to the low and mid 40s during the day however with overcast
skies expected, have a feeling temperatures will have trouble
getting out of the 30s. Therefore, will call for precipitation type
mostly in light snow or flurry category as any warm layer will be
confined to the surface and low level lapse rates will quickly
steepen. Could even see a few snow bursts through the day on
Wednesday as low levels edge toward a low degree of convective
instability. Again, expecting no real accumulations. Flurries or
sprinkles will linger through the day on Wednesday, along with
mostly cloudy skies.
.Long Term (Wednesday night - Monday)...
Wednesday night through Thursday night...
Main upper impulse will be exiting the area, but still expect some
residual low-level moisture to lingering Wednesday evening.
Subsidence and very shallow moist layer weigh against any precip so
no POPs in the forecast, but moisture and NW flow are sufficient
reason to hold onto a few early evening snow flurries in the eastern
tier.
Cold and dry high pressure on Thursday, with a broad, weak upper
trof overhead. MOS guidance is generally too warm in a shallow cold
air mass like this, so this forecast is more in line with the raw
model temps, with highs in the lower 40s in spite of full sunshine.
Clear and chilly Thursday night, but lows in the mid-upper 20s are
right in line with climo.
Friday through Monday...
Low-confidence forecast here as the models start to diverge. ECMWF
and GFS both drag some combination of a Clipper and/or cold front
across the Ohio Valley Friday night. ECMWF is trending more bullish
with southern-stream phasing and associated moisture. Will not jump
on this solution just yet but it bears watching. For now will go
with a slight chance for snow showers Fri night, mainly east of
I-65.
Cold high pressure plunges south from Canada for the weekend. Below
normal temperatures are a slam dunk but the question remains, how
much below normal? Coldest 850mb temps will be Saturday, when GFS
gets as cold as -14C. Current forecast max temps in the mid 30s may
be a bit too warm. Coldest night is Sat night, with lower 20s
across most locations. Not going for the quick rebound indicated by
extended GFS MOS on Sunday, given the cold start and model bias of
moving a high pressure ridge east too quickly. Expect highs in the
mid/upper 30s even with the thermal trof to our east.
Another southern stream system will affect the Ohio Valley early
next week, but model discrepancies are too large to jump on any one
solution just yet. Will keep Monday dry for now, as the quicker
ECMWF is also the less bullish model as far as QPF. Temps recover to
the high side of normal by Monday.
&&
.Aviation (12Z TAF Issuance)...
Surface high pressure will remain in control at the surface and
aloft through most of today before conditions deteriorate after
midnight as light snow overspreads much of the region. Will have to
deal with some patchy fog early this morning, with BWG having the
most persistent MVFR vis with temporary IFR possible. SDF and LEX
are more likely to stay VFR. Otherwise, expect increasing upper
level sky cover through the day with generally northwest winds
around 5 mph.
After Midnight, light snow is expected to overspread SDF/LEX with
visibilities around the MVFR/VFR threshold and ceilings solidly in
the MVFR range. Further south, BWG should expect mostly rain or a
rain/snow mix with MVFR ceilings.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......BJS
Long Term........RAS
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
314 AM EST TUE FEB 07 2012
.Short Term (Today - Wednesday)...
High pressure in place along with weak ridging aloft will keep
things dry today, although will have to deal with patchy
fog/freezing fog potential again through the morning hours. IR
satellite imagery currently shows a batch of low stratus across the
Great Lakes region to as far south as the I 74 corridor over central
and southern Indiana. HRRR has been consistent in showing these
clouds marching steadily southeast through the pre-dawn hours,
arriving near the Ohio River just after dawn. Therefore, skies
should clear in most spots with calm winds and subsident airmass.
This will lead to patchy fog formation, some of which will likely be
dense around dawn. Most likely areas will be in valleys and near
rivers and streams. With temperatures below freezing in most spots
will have to watch for slick spots. Will spend the rest of the
morning monitoring obs and issuing SPS or headline products if need
be. Right now, the only real indication of fog is over the Lake
Cumberland region.
Above mentioned status deck will likely scatter out over southern
Indiana this morning with upper level clouds beginning stream
overhead through the day. With low temperatures cooler than expected
this morning, have lowered highs a bit for this afternoon. Southern
Indiana will likely not make it out of the upper 40s with lower
level cloud cover this morning. Elsewhere, lower 50s can be expected
with mid 50s possible south.
The next weather making system will arrive after Midnight tonight as
an upper level impulse quickly ejects across the plains, absorbing
an upper low currently over NE Colorado. What may initially start
out as rain or a rain/snow mix across southern Indiana and central
Kentucky should quickly change over to snow as wet bulbing occurs
with low level saturation. Surface temperatures may stay just above
freezing in a few locations however warm layer at the surface will
be very shallow and should still support mostly snow. South of a
Bowling Green to Lake Cumberland line, precipitation type is more in
question and could end up being more rain and possibly a rain/snow
mix by dawn.
Best chances for precipitation, whether it be rain or snow, will be
from 3 AM EST to 8 AM EST early Wednesday. Will have to watch for a
moderate band of snow setting up anywhere from along and south of
the Ohio River to along and north of a Bowling Green to Lexington
line between 3 AM EST and dawn. This will occur just ahead of sharp
shortwave trough axis with frontogenesis coinciding with the left
exit region of an intensifying 100 to 120 knot upper level jet.
Models continue to indicate low amounts of QPF with this quick
hitting system, although have steadily increased amounts. Will have
to watch trends over the next 24 hours as banding does appear
possible with this setup and could produce a narrow swath of higher
QPF. That being said, ground and road temperatures should be well
above freezing with recent warm weather so do not expect any real
accumulation on these surfaces. Could see a dusting on grassy and
elevated surfaces by the daylight hours on Wednesday.
Upper level features quickly depart to the east by midday Wednesday,
however plentiful low level moisture between 1000-850 mb suggests
some flurries or sprinkles will be possible. Models are suggesting a
warm up to the low and mid 40s during the day however with overcast
skies expected, have a feeling temperatures will have trouble
getting out of the 30s. Therefore, will call for precipitation type
mostly in light snow or flurry category as any warm layer will be
confined to the surface and low level lapse rates will quickly
steepen. Could even see a few snow bursts through the day on
Wednesday as low levels edge toward a low degree of convective
instability. Again, expecting no real accumulations. Flurries or
sprinkles will linger through the day on Wednesday, along with
mostly cloudy skies.
.Long Term (Wednesday night - Monday)...
Wednesday night through Thursday night...
Main upper impulse will be exiting the area, but still expect some
residual low-level moisture to lingering Wednesday evening.
Subsidence and very shallow moist layer weigh against any precip so
no POPs in the forecast, but moisture and NW flow are sufficient
reason to hold onto a few early evening snow flurries in the eastern
tier.
Cold and dry high pressure on Thursday, with a broad, weak upper
trof overhead. MOS guidance is generally too warm in a shallow cold
air mass like this, so this forecast is more in line with the raw
model temps, with highs in the lower 40s in spite of full sunshine.
Clear and chilly Thursday night, but lows in the mid-upper 20s are
right in line with climo.
Friday through Monday...
Low-confidence forecast here as the models start to diverge. ECMWF
and GFS both drag some combination of a Clipper and/or cold front
across the Ohio Valley Friday night. ECMWF is trending more bullish
with southern-stream phasing and associated moisture. Will not jump
on this solution just yet but it bears watching. For now will go
with a slight chance for snow showers Fri night, mainly east of
I-65.
Cold high pressure plunges south from Canada for the weekend. Below
normal temperatures are a slam dunk but the question remains, how
much below normal? Coldest 850mb temps will be Saturday, when GFS
gets as cold as -14C. Current forecast max temps in the mid 30s may
be a bit too warm. Coldest night is Sat night, with lower 20s
across most locations. Not going for the quick rebound indicated by
extended GFS MOS on Sunday, given the cold start and model bias of
moving a high pressure ridge east too quickly. Expect highs in the
mid/upper 30s even with the thermal trof to our east.
Another southern stream system will affect the Ohio Valley early
next week, but model discrepancies are too large to jump on any one
solution just yet. Will keep Monday dry for now, as the quicker
ECMWF is also the less bullish model as far as QPF. Temps recover to
the high side of normal by Monday.
&&
.Aviation (06Z TAF Issuance)...
High pressure at the surface and aloft will control the weather for
much of the day, however will provide the proper ingredients for fog
formation toward dawn. With nearly calm winds, clear skies, and a
moist surface from recent rains feel the TAF sites will see some
MVFR and possibly IFR visibilities around dawn. Latest satellite
imagery shows low stratus over central Indiana that will gradually
build south through the pre-dawn hours, making it near the Ohio
River around dawn. Will actually keep forecast optimistic after
sunrise as MVFR visibilities at SDF/LEX quickly go back to VFR and
only FEW/SCT stratocu make it south of the river through the morning
hours. Expect BWG to see the usual low MVFR/IFR fog under good
radiational cooling, quickly going back to VFR after dawn.
Expect a quiet day otherwise with northwest winds and increasing mid
level clouds. Expect chances for rain/snow to begin just after the
forecast period early Wednesday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......BJS
Long Term........RAS
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1227 PM EST TUE FEB 7 2012
.SYNOPSIS...
A SHALLOW COLD FRONT WILL SPREAD LOW CLOUDS ACROSS THE UPPER OHIO
VALLEY AND SOUTH OF THE MASON DIXON LINE THIS AFTERNOON. LOW PRESSURE WILL
MOVE EASTWARD ALONG THE STALLED FRONT WEDNESDAY, AND BRING SNOW
SHOWERS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LITTLE CHANGE TO PREVIOUS FORECAST FOR EARLY AFTERNOON UPDATE WITH
ONLY A FEW CHANGES TO SKY GRIDS. RAISED MAX TEMPS A DEGREE OR TWO
BASED ON NOON READINGS. WEAK AND HARD TO FIND BOUNDARY SAGGING
SOUTH AND WILL STALL AS SHORTWAVE APPROACHES FROM THE SOUTHWEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
SHORTWAVE IN THE SOUTHERN STREAM OF CONFLUENT FLOW PROJECTED OVER
THE REGION IS PROGGED TO GENERATE SNOW SHOWERS ALONG THE SOUTHWARD
SAGGING, AFOREMENTIONED COLD FRONT LATE TUESDAY NIGHT/WEDNESDAY.
CHANCE PRECIP PROBABILITIES WERE INCLUDED FOR THIS SCENARIO, BUT
WITH BETTER NUMBERS OVER SOUTHERN ZONES DUE TO EXPECTED PROGRESS
OF THE FRONT. LIKELY NUMBERS THAT WERE FORECAST FOR THE RIDGES ARE
DUE TO EXTRA SUPPORT VIA DEVELOPING UPSLOPE.
OVERALL, LIGHT SNOW ACCUMULATION IS POSSIBLE ON WEDNESDAY WITH
AMOUNTS LIMITED BY THE PROGRESSIVE NATURE OF THE SYSTEM AND
SURFACE TEMPERATURES ABOVE FREEZING.
TEMPERATURES WERE FORECAST NEAR NORMAL USING A BLEND OF GUIDANCE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LATEST ECMWF AND GFS MODEL OUTPUT SHOWS A DEEP UPPER TROUGH SWINGING
THROUGH EASTERN CANADA BY THE WEEKEND. TIMING OF THE ASSOCIATED
COLD FRONT STILL VARIES SOMEWHAT BETWEEN GFS/ECMWF, BUT LATEST
THINKING IS THAT THE FRONT WILL PUSH ACROSS THE FORECAST AREA LATE
FRIDAY, BRINGING SCATTERED SNOW SHOWERS, POSSIBLY MIXING WITH RAIN
SHOWERS IN THE SOUTH, AND A RETURN TO MORE WINTER-LIKE TEMPERATURES.
SURFACE HIGH PRESSURE AND DRIER AIR ARE PROJECTED TO MOVE OVER
THE OHIO VALLEY ON SUNDAY AND MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
PER BLEND OF RECENT SURFACE AND SATELLITE DATA, NAM AND HRRR MODEL
OUTPUT, AND GFS LAMP, EXPECT SHALLOW COLD FRONTAL BAND OF
STRATOCUMULUS, SPREADING SOUTHWARD AT 15 KTS, TO GET AS FAR SOUTH
AS THE MASON-DIXON LINE BY 16Z, BEFORE STOPPING. CEILINGS WILL BE
MAINLY AT MVFR LEVELS, BUT BRIEF IFR INTERLUDES CANNOT BE RULED
OUT THIS MORNING. HAVE LOW CONFIDENCE THAT THE CLOUDS REACH KMGW.
TERMINALS SUCH AS KZZV, KHLG, AND KLBE MAY SEE CLOUD COVERAGE GO
SCATTERED FOR A TIME THIS AFTERNOON.
IN GENERAL, EXPECT MVFR CEILINGS TONIGHT, EVEN AT KMGW LATE
TONIGHT, AS LOW PRESSURE APPROACHES FROM THE WEST.
SURFACE WINDS WILL GO TO NORTH-NORTHWEST NEAR 10 KTS BY MIDDAY.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
AN EASTBOUND LOW PRESSURE SYSTEM WILL DEEPEN THE COLD FRONT TO YIELD
MVFR SNOW SHOWERS BY DAYTIME WEDNESDAY. ENSUING HIGH PRESSURE WILL
PROVIDE VFR THURSDAY AND FRIDAY. A COLD FRONTAL BAND OF SNOW
SHOWERS WILL PROVIDE RESTRICTIONS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
956 AM EST TUE FEB 7 2012
.SYNOPSIS...
A SHALLOW COLD FRONT WILL SPREAD LOW CLOUDS ACROSS THE UPPER OHIO
VALLEY AND SOUTH OF THE MASON DIXON LINE THIS AFTERNOON. LOW PRESSURE WILL
MOVE EASTWARD ALONG THE STALLED FRONT WEDNESDAY, AND BRING SNOW
SHOWERS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID MORNING UPDATE TO BRING STRATUS DECK SOUTH AS AFTERNOON
PROGRESSES WITH CURRENT SPREAD OF DECK TO REACH SOUTHERN TIER OF
COUNTIES DURING TE AFTERNOON. CURRENT FORECAST MAX TEMPS LOOK IN
LINE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
SHORTWAVE IN THE SOUTHERN STREAM OF CONFLUENT FLOW PROJECTED OVER
THE REGION IS PROGGED TO GENERATE SNOW SHOWERS ALONG THE SOUTHWARD
SAGGING, AFOREMENTIONED COLD FRONT LATE TUESDAY NIGHT/WEDNESDAY.
CHANCE PRECIP PROBABILITIES WERE INCLUDED FOR THIS SCENARIO, BUT
WITH BETTER NUMBERS OVER SOUTHERN ZONES DUE TO EXPECTED PROGRESS
OF THE FRONT. LIKELY NUMBERS THAT WERE FORECAST FOR THE RIDGES ARE
DUE TO EXTRA SUPPORT VIA DEVELOPING UPSLOPE.
OVERALL, LIGHT SNOW ACCUMULATION IS POSSIBLE ON WEDNESDAY WITH
AMOUNTS LIMITED BY THE PROGRESSIVE NATURE OF THE SYSTEM AND
SURFACE TEMPERATURES ABOVE FREEZING.
TEMPERATURES WERE FORECAST NEAR NORMAL USING A BLEND OF GUIDANCE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LATEST ECMWF AND GFS MODEL OUTPUT SHOWS A DEEP UPPER TROUGH SWINGING
THROUGH EASTERN CANADA BY THE WEEKEND. TIMING OF THE ASSOCIATED
COLD FRONT STILL VARIES SOMEWHAT BETWEEN GFS/ECMWF, BUT LATEST
THINKING IS THAT THE FRONT WILL PUSH ACROSS THE FORECAST AREA LATE
FRIDAY, BRINGING SCATTERED SNOW SHOWERS, POSSIBLY MIXING WITH RAIN
SHOWERS IN THE SOUTH, AND A RETURN TO MORE WINTER-LIKE TEMPERATURES.
SURFACE HIGH PRESSURE AND DRIER AIR ARE PROJECTED TO MOVE OVER
THE OHIO VALLEY ON SUNDAY AND MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
PER BLEND OF RECENT SURFACE AND SATELLITE DATA, NAM AND HRRR MODEL
OUTPUT, AND GFS LAMP, EXPECT SHALLOW COLD FRONTAL BAND OF
STRATOCUMULUS, SPREADING SOUTHWARD AT 15 KTS, TO GET AS FAR SOUTH
AS THE MASON-DIXON LINE BY 16Z, BEFORE STOPPING. CEILINGS WILL BE
MAINLY AT MVFR LEVELS, BUT BRIEF IFR INTERLUDES CANNOT BE RULED
OUT THIS MORNING. HAVE LOW CONFIDENCE THAT THE CLOUDS REACH KMGW.
TERMINALS SUCH AS KZZV, KHLG, AND KLBE MAY SEE CLOUD COVERAGE GO
SCATTERED FOR A TIME THIS AFTERNOON.
IN GENERAL, EXPECT MVFR CEILINGS TONIGHT, EVEN AT KMGW LATE
TONIGHT, AS LOW PRESSURE APPROACHES FROM THE WEST.
SURFACE WINDS WILL GO TO NORTH-NORTHWEST NEAR 10 KTS BY MIDDAY.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
AN EASTBOUND LOW PRESSURE SYSTEM WILL DEEPEN THE COLD FRONT TO YIELD
MVFR SNOW SHOWERS BY DAYTIME WEDNESDAY. ENSUING HIGH PRESSURE WILL
PROVIDE VFR THURSDAY AND FRIDAY. A COLD FRONTAL BAND OF SNOW
SHOWERS WILL PROVIDE RESTRICTIONS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
642 AM EST TUE FEB 7 2012
.SYNOPSIS...
A SHALLOW COLD FRONT WILL SPREAD LOW CLOUDS ACROSS THE UPPER OHIO
VALLEY AS FAR SOUTH AS THE MASON DIXON LINE. LOW PRESSURE WILL
MOVE EASTWARD ALONG THE STALLED FRONT WEDNESDAY, AND BRING SNOW
SHOWERS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE TWEAKED SOUTHWARD SPREAD OF LOW CLOUDS ACROSS THE UPPER OHIO
VALLEY BASED ON RECENT SATELLITE DATA AND HRRR MODEL OUTPUT. THE
CLOUDS ARE ASSOCIATED WITH A SHALLOW COLD FRONT, THAT IS EXPECTED
TO STALL NEAR THE MASON-DIXON LINE.
THE CLOUDS WILL HAVE A BIG EFFECT ON SUNSHINE AND TEMPERATURES
TODAY, WITH CLOUDY AREAS A FEW DEGREES COLDER THAN SUNNY NORTHERN
WEST VIRGINIA. HAVE FORECASTED TEMPERATURE DETAILS USING BLEND OF
SREF AND HRRR MODEL OUTPUT AND GFS MOS AND LAMP.
THERE IS THE POSSIBILITY THAT AREAS STRADDLING THE I-70 CORRIDOR
CAN GET A LITTLE SUN THIS AFTERNOON, AS HRRR AND NAM MODEL OUTPUT
SUGGEST THERE MAY BE SOME EROSION OF THE THIN CLOUDS NEAR THE
CLOUD BANKS SOUTHERN EDGE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
SHORTWAVE IN THE SOUTHERN STREAM OF CONFLUENT FLOW PROJECTED OVER
THE REGION IS PROGGED TO GENERATE SNOW SHOWERS ALONG THE SOUTHWARD
SAGGING, AFOREMENTIONED COLD FRONT LATE TUESDAY NIGHT/WEDNESDAY.
CHANCE PRECIP PROBABILITIES WERE INCLUDED FOR THIS SCENARIO, BUT
WITH BETTER NUMBERS OVER SOUTHERN ZONES DUE TO EXPECTED PROGRESS
OF THE FRONT. LIKELY NUMBERS THAT WERE FORECAST FOR THE RIDGES ARE
DUE TO EXTRA SUPPORT VIA DEVELOPING UPSLOPE.
OVERALL, LIGHT SNOW ACCUMULATION IS POSSIBLE ON WEDNESDAY WITH
AMOUNTS LIMITED BY THE PROGRESSIVE NATURE OF THE SYSTEM AND
SURFACE TEMPERATURES ABOVE FREEZING.
TEMPERATURES WERE FORECAST NEAR NORMAL USING A BLEND OF GUIDANCE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LATEST ECMWF AND GFS MODEL OUTPUT SHOWS A DEEP UPPER TROUGH SWINGING
THROUGH EASTERN CANADA BY THE WEEKEND. TIMING OF THE ASSOCIATED
COLD FRONT STILL VARIES SOMEWHAT BETWEEN GFS/ECMWF, BUT LATEST
THINKING IS THAT THE FRONT WILL PUSH ACROSS THE FORECAST AREA LATE
FRIDAY, BRINGING SCATTERED SNOW SHOWERS, POSSIBLY MIXING WITH RAIN
SHOWERS IN THE SOUTH, AND A RETURN TO MORE WINTER-LIKE TEMPERATURES.
SURFACE HIGH PRESSURE AND DRIER AIR ARE PROJECTED TO MOVE OVER
THE OHIO VALLEY ON SUNDAY AND MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
PER BLEND OF RECENT SURFACE AND SATELLITE DATA, NAM AND HRRR MODEL
OUTPUT, AND GFS LAMP, EXPECT SHALLOW COLD FRONTAL BAND OF
STRATOCUMULUS, SPREADING SOUTHWARD AT 15 KTS, TO GET AS FAR SOUTH
AS THE MASON-DIXON LINE BY 16Z, BEFORE STOPPING. CEILINGS WILL BE
MAINLY AT MVFR LEVELS, BUT BRIEF IFR INTERLUDES CANNOT BE RULED
OUT THIS MORNING. HAVE LOW CONFIDENCE THAT THE CLOUDS REACH KMGW.
TERMINALS SUCH AS KZZV, KHLG, AND KLBE MAY SEE CLOUD COVERAGE GO
SCATTERED FOR A TIME THIS AFTERNOON.
IN GENERAL, EXPECT MVFR CEILINGS TONIGHT, EVEN AT KMGW LATE
TONIGHT, AS LOW PRESSURE APPROACHES FROM THE WEST.
SURFACE WINDS WILL GO TO NORTH-NORTHWEST NEAR 10 KTS BY MIDDAY.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
AN EASTBOUND LOW PRESSURE SYSTEM WILL DEEPEN THE COLD FRONT TO YIELD
MVFR SNOW SHOWERS BY DAYTIME WEDNESDAY. ENSUING HIGH PRESSURE WILL
PROVIDE VFR THURSDAY AND FRIDAY. A COLD FRONTAL BAND OF SNOW
SHOWERS WILL PROVIDE RESTRICTIONS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
401 AM EST TUE FEB 7 2012
.SYNOPSIS...
A DRY, BUT CLOUDY AND COLD DAY ACROSS MUCH OF THE AREA. LOCATIONS
WELL SOUTH OF PITTSBURGH, WILL SEE MORE SUN AND WARMER
TEMPERATURES. LOW PRESSURE WILL BRING WIDESPREAD SNOW SHOWERS TO
THE AREA WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW CLOUDS ARE NOW MOVING SOUTHWARD ACROSS THE NORTHERN HALF OF
THE FORECAST AREA. LATEST HRRR HAS A GOOD HANDLE ON THE TIMING.
EXPECT CLOUDS TO REACH PIT BY 12Z AND THE PA-WV BORDER BY 15Z.
LOOKS LIKE THE CLOUDS WILL STOP HERE, LEAVING MUCH OF N WV, WITH
THE EXCEPTION OF THE PANHANDLE, MAINLY SUNNY.
THE CLOUDS WILL HAVE A BIG EFFECT ON TEMPS TODAY. OBVIOUSLY, WHERE
THE CLOUDS ARE, TEMPS WILL BE LOWER, WHERE THE CLOUDS AREN`T,
WARMER TEMPS. UNDER THE CLOUD COVER, WILL LEAN CLOSER TO THE
COLDER 21Z SREF, SOUTH OF THE CLOUD COVER, WILL HAVE NUMBERS
CLOSE TO THE 00Z MAV.
MODELS ARE SHOWING BOUNDARY LAYER MOISTURE DECREASING A BIT THIS
AFTERNOON. THIS MAY ALLOW FOR THE SOUTHERN PORTION OF THE CLOUDS
DECK TO BREAK UP, BUT WOULD EXPECT NORTHERN LOCATIONS TO REMAIN
CLOUDY ALL DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
SHORTWAVE IN THE SOUTHERN STREAM OF CONFLUENT FLOW PROJECTED OVER
THE REGION IS PROGGED TO GENERATE SNOW SHOWERS ALONG THE SOUTHWARD
SAGGING, AFOREMENTIONED COLD FRONT LATE TUESDAY NIGHT/WEDNESDAY.
CHANCE PRECIP PROBABILITIES WERE INCLUDED FOR THIS SCENARIO, BUT
WITH BETTER NUMBERS OVER SOUTHERN ZONES DUE TO EXPECTED PROGRESS
OF THE FRONT. LIKELY NUMBERS THAT WERE FORECAST FOR THE RIDGES ARE
DUE TO EXTRA SUPPORT VIA DEVELOPING UPSLOPE.
OVERALL, LIGHT SNOW ACCUMULATION IS POSSIBLE ON WEDNESDAY WITH
AMOUNTS LIMITED BY THE PROGRESSIVE NATURE OF THE SYSTEM AND
SURFACE TEMPERATURES ABOVE FREEZING.
TEMPERATURES WERE FORECAST NEAR NORMAL USING A BLEND OF GUIDANCE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LATEST ECMWF AND GFS MODEL OUTPUT SHOWS A DEEP UPPER TROUGH SWINGING
THROUGH EASTERN CANADA BY THE WEEKEND. TIMING OF THE ASSOCIATED
COLD FRONT STILL VARIES SOMEWHAT BETWEEN GFS/ECMWF, BUT LATEST
THINKING IS THAT THE FRONT WILL PUSH ACROSS THE FORECAST AREA LATE
FRIDAY, BRINGING SCATTERED SNOW SHOWERS, POSSIBLY MIXING WITH RAIN
SHOWERS IN THE SOUTH, AND A RETURN TO MORE WINTER-LIKE TEMPERATURES.
SURFACE HIGH PRESSURE AND DRIER AIR ARE PROJECTED TO MOVE OVER
THE OHIO VALLEY ON SUNDAY AND MONDAY.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
PER BLEND OF RECENT SURFACE AND SATELLITE DATA, NAM AND HRRR MODEL
OUTPUT, AND GFS LAMP, EXPECT SHALLOW COLD FRONTAL BAND OF
STRATOCUMULUS TO SPREAD SOUTHWARD AT 25 KTS THROUGH MUCH OF THE
UPPER OHIO VALLEY OVERNIGHT. CEILINGS, GENERALLY 8-15 HFT, WILL
STRADDLE IFR LEVELS, AND REACH AS FAR SOUTH AS KZZV-KHLG-KLBE BY
13Z. HAVE LOW CONFIDENCE THAT THE CLOUDS REACH KMGW.
SURFACE WINDS WILL GO FROM WEST NEAR 5 KTS TO NORTH-NORTHWEST NEAR
10 KTS BY MIDDAY.
EXPECT ANY IFR CEILINGS TO LIFT TO MVFR LEVELS BY AFTERNOON, AND
REMAIN MVFR TONIGHT. THERE MAY EVEN BE SUFFICIENT EROSION FOR
SOUTHERN CEILINGS TO DISSIPATE FOR A WHILE.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
AN EASTBOUND LOW PRESSURE SYSTEM WILL DEEPEN THE COLD FRONT TO YIELD
MVFR SNOW SHOWERS BY DAYTIME WEDNESDAY. ENSUING HIGH PRESSURE WILL
PROVIDE VFR THURSDAY AND FRIDAY. A COLD FRONTAL BAND OF SNOW
SHOWERS WILL PROVIDE RESTRICTIONS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1253 AM EST TUE FEB 7 2012
.SYNOPSIS...
A DRY, BUT CLOUDY AND COLD DAY ACROSS MUCH OF THE AREA. LOCATIONS
SOUTH OF PITTSBURGH MAY SEE MORE SUN AND WARMER TEMPERATURES. LOW
PRESSURE WILL BRING WIDESPREAD SNOW SHOWERS TO THE AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
BIGGEST CHANGE TO PREVIOUS FORECAST IS THE INCREASE IN CLOUD COVER
FROM NORTH TO SOUTH AS DAWN APPROACHES. LATEST 00Z RUN AND 02Z HRRR,
INDICATE THE AREA OF SC OVER NW OHIO AND THE GREAT LAKES FILLING
IN AND SLOWLY MOVING SOUTHWARD. IT APPEARS THAT THESE CLOUDS ARE
ASSOCIATED WITH A WEAK COLD FRONT, WHICH WILL WASH OUT OVER
SOUTHERN PA THIS AFTERNOON. MODELS ARE SHOWING THAT NEITHER THE
FRONT, NOR THE CLOUDS, WILL REACH FAR SOUTHERN PA OR N WV.
THE CLOUDS WILL HAVE A BIG EFFECT ON TEMPS TODAY. OBVIOUSLY, WHERE
THE CLOUDS ARE, TEMPS WILL BE LOWER, WHERE THE CLOUDS AREN`T,
WARMER TEMPS. UNDER THE CLOUD COVER, WILL LEAN CLOSER TO THE
COLDER 21Z SREF, SOUTH OF THE CLOUD COVER, WILL HAVE NUMBERS
CLOSE TO THE 00Z MAV.
MODELS ARE SHOWING BOUNDARY LAYER MOISTURE DECREASING A BIT THIS
AFTERNOON. THIS MAY ALLOW FOR THE SOUTHERN PORTION OF THE CLOUDS
DECK TO BREAK UP, BUT WOULD EXPECT NORTHERN LOCATIONS TO REMAIN
CLOUDY ALL DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
SHORTWAVE IN THE SOUTHERN STREAM OF CONFLUENT FLOW PROJECTED OVER
THE REGION IS PROGGED TO GENERATE SNOW SHOWERS ALONG THE SOUTHWARD
SAGGING, AFOREMENTIONED COLD FRONT LATE TUESDAY NIGHT/WEDNESDAY.
CHANCE PRECIP PROBABILITIES WERE INCLUDED FOR THIS SCENARIO, BUT
WITH BETTER NUMBERS OVER SOUTHERN ZONES DUE TO EXPECTED PROGRESS
OF THE FRONT. LIKELY NUMBERS THAT WERE FORECAST FOR THE RIDGES ARE
DUE TO EXTRA SUPPORT VIA DEVELOPING UPSLOPE.
OVERALL, LIGHT SNOW ACCUMULATION IS POSSIBLE ON WEDNESDAY WITH
AMOUNTS LIMITED BY THE PROGRESSIVE NATURE OF THE SYSTEM.
TEMPERATURES WERE FORECAST NEAR NORMAL USING A BLEND OF GUIDANCE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
LATEST ECMWF AND GFS MODEL OUTPUT SHOWS A DEEP UPPER TROUGH SWINGING
THROUGH EASTERN CANADA BY THE WEEKEND. TIMING OF THE ASSOCIATED
COLD FRONT STILL VARIES SOMEWHAT BETWEEN GFS/ECMWF, BUT LATEST
THINKING IS THAT THE FRONT WILL PUSH ACROSS THE FORECAST AREA LATE
FRIDAY, BRINGING SCATTERED SNOW SHOWERS, POSSIBLY MIXING WITH RAIN
SHOWERS IN THE SOUTH, AND A RETURN TO MORE WINTER-LIKE TEMPERATURES.
SURFACE HIGH PRESSURE AND DRIER AIR ARE PROJECTED TO MOVE OVER
THE OHIO VALLEY ON SUNDAY AND MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
PER BLEND OF RECENT SURFACE AND SATELLITE DATA, NAM AND HRRR MODEL
OUTPUT, AND GFS LAMP, EXPECT SHALLOW COLD FRONTAL BAND OF
STRATOCUMULUS TO SPREAD SOUTHWARD AT 25 KTS THROUGH MUCH OF THE
UPPER OHIO VALLEY OVERNIGHT. CEILINGS, GENERALLY 8-15 HFT, WILL
STRADDLE IFR LEVELS, AND REACH AS FAR SOUTH AS KZZV-KHLG-KLBE BY
13Z. HAVE LOW CONFIDENCE THAT THE CLOUDS REACH KMGW.
SURFACE WINDS WILL GO FROM WEST NEAR 5 KTS TO NORTH-NORTHWEST NEAR
10 KTS BY MIDDAY.
EXPECT ANY IFR CEILINGS TO LIFT TO MVFR LEVELS BY AFTERNOON, AND
REMAIN MVFR TONIGHT. THERE MAY EVEN BE SUFFICIENT EROSION FOR
SOUTHERN CEILINGS TO DISSIPATE FOR A WHILE.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
AN EASTBOUND LOW PRESSURE SYSTEM WILL DEEPEN THE COLD FRONT TO YIELD
MVFR SNOW SHOWERS BY DAYTIME WEDNESDAY. ENSUING HIGH PRESSURE WILL
PROVIDE VFR THURSDAY AND FRIDAY. A COLD FRONTAL BAND OF SNOW
SHOWERS WILL PROVIDE RESTRICTIONS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
133 PM EST TUE FEB 7 2012
.UPDATE...
ISSUED AT 133 PM EST TUE FEB 7 2012
LAKE EFFECT SNOW SHOWERS CONTINUE TO DIMINISH RAPIDLY AS DRY AIR
CONTINUES TO MOVE INTO THE AREA AND ANTICYCLONIC FLOW AND LACK OF
LOW LEVEL CONVERGENCE ALSO HELPS TO ERODE THE CLOUDS AND LAKE EFFECT
SNOW SHOWERS. CUT POPS BACK AND DECREASED CLOUD COVER.
&&
.SYNOPSIS...
ISSUED AT 427 AM EST TUE FEB 7 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RATHER SHEARED
POSITIVELY TILTED SHRTWV DROPPING SEWD THRU THE UPR LKS IN
PREVAILING NW FLOW ALF BTWN TROF OVER QUEBEC AND UPR RDG OVER WRN
CAN. ACCOMPANYING SHARP COLD FNT THAT SURGED THRU THE FA YDAY HAS
NOW PUSHED TO THE S. ALTHOUGH MUCH COLDER AIR IS FOLLOWING THE FNT
WITH NNE FLOW AND 00Z H85 TEMPS RANGING FM 0C AT GRB TO -10C AT INL
AND -17C AT YPL...SGNFT LES HAS NOT DEVELOPED EVEN IN AREAS FAVORED
BY THE NNE FLOW. KEY FACTORS APPEAR TO BE IMPRESSIVE DRYING
REFLECTED BY 00Z YPL RAOB /00Z PWAT 0.06 INCH/ THAT IS STEADILY
ERODING THE BACK EDGE OF THE LK CLD AS SHOWN ON IR STLT IMAGERY...
SUBSIDENCE ASSOCIATED WITH FAIRLY VIGOROUS DNVA/CAD/DEEP LYR QVECTOR
DVGC IN THE WAKE OF THE SHRTWV THAT IS CAUSING THE LLVL FLOW TO
BECOME ACYC AND SINK INVRN BASE TO ARND H9 AS SHOWN ON THE 00Z INL
AND YPL RAOBS. UNDER SFC RDG AXIS IN ONTARIO EXTENDING E FM HI
CENTER NEAR LK WINNIPEG...SKIES ARE MOCLR...AND SFC TEMPS/DWPTS HAVE
FALLEN INTO THE ZERO TO -10F RANGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 427 AM EST TUE FEB 7 2012
TODAY...COLD NLY FLOW IS FCST TO PERSIST THRU THIS MRNG BEFORE HI
PRES CENTER BLDG FM LK WINNIPEG INTO MN CAUSES THE LLVL FLOW TO BACK
TO THE W BY LATE IN THE DAY. THE COLDEST MODELS...NOTABLY THE 00Z
CNDN AND LOW WRF-ARW...SHOW H85 TEMPS SINKING TO -15 TO -17C OVER
SCNTRL LK SUP THIS MRNG WHILE THE WARMER 00Z NAM/GFS INDICATE THESE
TEMPS WL FALL NO LOWER THAN -14C OR SO. THE DIFFERENCE APPEARS TO BE
RELATED TO THE INVRN HGT FCST...WITH THE WARMER MODELS INDICATING A
LOWER INVRN BASE AOB 3K FT /NAM/ AS COMPARED TO ARND 4K FT
/WRF-ARW/. SINCE DEEP LYR QVECTOR DVGC/SUBSIDENCE WL INTENSIFY THRU
THE DAY AND TRENDS ON OBSVD SKY COVER OVER LK SUP SUG THE INVRN IS
CRASHING...WL TEND TO FOLLOW THE WARMER/LO INVRN BASE DEPICTED BY
THE 00Z NAM. THIS MODEL SHOWS ALMOST NO PCPN EVEN IN THE N WIND SN
BELTS WITH DIFFLUENT FLOW/H925-85 DEWPT DEPRESSION AS HI AS 7-10C
EVEN OVER THE N WIND SN BELTS THAT WOULD OTRW BE FAVORED BY THE LLVL
FLOW. SO ALTHOUGH SOME LES IS LIKELY TO BREAK OUT IN THE NEXT FEW
HRS THRU 12Z WITH THE ARRIVAL OF COLDER AIR...ANY SN ACCUM SHOULD BE
NO MORE THAN ARND AN INCH EVEN OVER THE HIER TERRAIN. BACKING MORE
ACYC FLOW THIS AFTN WITH INVRN BASE REMAINING BLO 3K FT SHOULD
DIMINISH THE LES FURTHER. ALTHOUGH DAYTIME TEMPS WL BE JUST A BIT
BELOW NORMAL...RECENT WARMTH WL MAKE THE DAY FEEL EVEN COLDER...
ESPECIALLY THIS MRNG WITH A STEADY N WIND.
TNGT...SFC HI PRES RDG AXIS IS FCST TO BE NEARLY OVHD IN THE EVNG
BUT THEN SHIFT TO THE S. WITH CONTINUED SUBSIDENCE AND THE FLOW
BACKING TO THE W...EXPECT SKIES TO TURN MOCLR EXCEPT PERHAPS OVER
THE KEWEENAW AND NEAR LK SUP E OF MUNISING. PWAT IS FCST TO BE 0.10
INCH AT 00Z...SO EXPECT A QUICK FALL OF TEMP IN THE EVNG WITH LGT
WINDS...SO ACCELERATED EARLY FALL OF TEMP. ONCE THE RDG SHIFTS TO
THE S OVERNGT...A STRONGER WNW WIND WL DVLP...WITH H925 WINDS FCST
UP TO 30-35 KTS. RETAINED GOING FCST MIN TEMPS AOB THE LO END OF
GUIDANCE PER VERY DRY AIR/OBSVD CHILL UPSTREAM OVER THE MORE
SHELTERED SRN TIER. TEMPS WL BE QUITE A BIT WARMER NEAR THE MORE
EXPOSED LK SUP AND UNDER THE SHARPER PRES GRADIENT FARTHER N OF THE
RDG AXIS...ESPECIALLY OVER THE E WHERE SOME LO CLDS MAY LINGER NEAR
THE SHORE THRU THE NGT UNDER WNW H925 FLOW.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 427 AM EST TUE FEB 7 2012
TROUGH WILL BE EXITING INTO EASTERN CANADA TO START THE LONG TERM
WHICH ALLOWS FOR HEIGHTS TO RISE FM PLAINS INTO GREAT LAKES. AT THE
SFC...HIGH PRESSURE OVER THE PLAINS SLIDES SOUTH ON WEDNESDAY
ALLOWING FOR WESTERLY WINDS AT LOW-LEVELS OVR UPR LAKES INTO
WEDNESDAY NIGHT. WEST WINDS ALONG WITH JUST SCT MID CLOUDS RESULTED
IN RAISING MAX TEMPS TOWARD HIGHER END OF GUIDANCE /AROUND 30 INLAND
AND INTO THE MID 30S NEAR LK SUPERIOR/. NEXT COLD FRONT WILL BE
DROPPING SOUTH ACROSS ONTARIO ON WEDNESDAY NIGHT...SO EXPECT AT
LEAST LGT WEST WINDS TO PERSIST THROUGH THE NIGHT. INLAND AREAS
COULD TRY TO DECOUPLE AND FALL INTO THE TEENS...BUT TEMPS ALONG
SHORELINES OF LK SUPERIOR AND LK MICHIGAN SHOULD STAY IN THE MID TO
UPR 20S. FCST SOUNDINGS FM BOTH NAM AND GFS INDICATE CONDITIONS TOO
DRY TO SUPPORT ANY PCPN AHEAD OF THE FRONT IN THE WESTERLY FLOW.
HAVE REMOVED ANY MENTION OF SNOW UNTIL THURSDAY...EVEN OVR THE
KEWEENAW PENINSULA.
CHANGES BEGIN TO OCCUR LATER THURSDAY AS ARCTIC COLD FRONT IS FCST
TO ARRIVE. PROBABLY WILL SEE FALLING TEMPS...BUT AT THIS POINT STUCK
WITH NORMAL DIURNAL TEMP CURVE AS PRIMARY COOLING FM FROPA DOES NOT
OCCUR UNTIL LATE IN THE DAY. SOUNDINGS SHOW SUFFICIENT MOISTENING TO
JUSTIFY SOME SNOW SHOWERS BY LATE AFTN OVR KEWEENAW. ELSEWHERE...
CHANCES OF PCPN ON THURSDAY LOOK MINIMAL. LK EFFECT THEN BECOMES
MORE OF AN ISSUE BY THURSDAY EVENING AS NW WINDS IN BLYR VEER MORE
NORTHERLY. H85 TEMPS FALLING BLO -20C PER GFS/ECMWF LEAD TO SURGE OF
OVER-WATER INSTABILITY WITH LAKE EFFECT EQL AOA 8KFT AND SFC-H85
LAPSE RATES OVR 9C/KM. INSTABILITY IS SUPPLEMENTED BY MID LEVEL
MOISTURE /UP TO H7/. OVERALL SETUP APPEARS FAVORABLE FOR MODERATE
AND POSSIBLY HEAVY LK EFFECT SNOW SHOWERS THURSDAY NIGHT INTO
FRIDAY. SNOW WILL BE FLUFFY AS MAJORITY OF LAKE EFFECT CONVECTIVE
LAYER IS WITHIN THE DENDRITIC GROWTH ZONE. SLR/S FM COBB METHOD IN
BUFKIT RISE WELL ABOVE 20:1.
ONLY MAIN ISSUE TO SORT OUT STILL IS EXACT BLYR WIND DIRECTION. NAM
IS STRONGEST WITH SFC TROUGH AND ASSOCIATED NORTHEAST WINDS DEVELOPING
IN THE WAKE OF THE TROUGH. GFS/ECMWF ARE MORE NORTHERLY WITH THE
WINDS WHILE CANADIAN SHOWS WINDS REMAINING FM NORTHWEST. DO LIKE THE
NAM IDEA INDICATING SHARP WIND SHIFT JUST IN WAKE OF ARCTIC
FRONT...BUT WENT WITH BLEND OF NAM AND PREVIOUS FCST FOR THE WINDS.
RESULT OF THIS CHOICE WAS SOLN WITH WINDS THAT LOOKED LIKE LATEST
ECMWF. GIVEN FAVORABLE OVER-WATER INSTABILITY AND EXPECTED NORTHERLY
WINDS...INCREASED POPS TO LIKELY OVR NORTH WIND SNOW BELTS IN FAR
WEST AND NORTH CENTRAL UPR MI. SEVERAL INCHES OF SNOW SEEMS POSSIBLE
THURSDAY NIGHT INTO FRIDAY...AND WILL CONTINUE TO MENTION THIS IN
THE HAZARDOUS WEATHER OUTLOOK.
IN THE EXTENDED...AGREEMENT IN OVERALL IDEA THAT FIRST PORTION OF
THE WEEKEND WILL BE DOMINANTED BY LINGERING COLD AIRMASS /H85 TEMPS
AROUND -20C/ THAT MOVES IN LATE THIS WEEK. LK EFFECT IN NORTH TO
NORTHWEST FLOW AREAS FRIDAY AND FRIDAY NIGHT WILL DIMINISH ON
SATURDAY AS WINDS TURN MORE WESTERLY AHEAD OF YET ANOTHER COLD
FRONT. BOTH GFS/ECMWF POINT TO CENTER OF POLAR VORTEX WITH H85 TEMPS
NEAR -30C TO FINALLY COME SOUTH INTO GREAT LAKES BY SUNDAY. VORTEX
IS QUITE COMPACT THOUGH AND IT SEEMS DIFFICULT AT BEST TO FCST WHERE
THE CORE OF COLDEST AIR WILL ACTUALLY TRAVEL. GFS IS FARTHER WEST
AND WOULD RESULT IN MIN TEMPS ON SATURDAY NIGHT WELL BLO ZERO IN THE
CNTRL AND EAST. ECMWF IS FARTHER EAST WITH THE VORTEX. SEEMS LIKE
TREND THIS WINTER OF ONLY GLANCING BLOWS OF COLDER AIR OVR UPR LAKES
WOULD SUPPORT THE ECMWF IDEA.
LK EFFECT MAY KICK UP AGAIN LATE IN THE WEEKEND...THOUGH LOW
INVERSION HEIGHTS AND VERY DRY LOW-LEVELS WILL KEEP ACCUMS IN CHECK.
BLEND OF MODELS WORKS FOR NOW...WHICH RESULTED IN SLIGHT CHANCES FOR
SNOW SHOWERS. DUE TO FINE NATURE OF CRYSTALS/NEEDLES IN SUCH A COLD
AIRMASS...THE MAIN IMPACT FM THE SNOW SHOWERS WOULD BE REDUCED
VSBY...ESPECIALLY WITH SOME WIND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1140 AM EST TUE FEB 7 2012
EXPECT MVFR CIGS TO GIVE WAY TO CLEARING/VFR CONDITIONS THIS
AFTERNOON WITH THE ARRIVAL OF DRY LOW LEVEL AIR. AS A HIGH PRESSURE
RIDGE SINKS TO THE SOUTH TONIGHT...EXPECT A GUSTY W WIND AT CMX
UNDER SHARPER PRES GRADIENT ON THE MORE EXPOSED KEWEENAW PENINSULA.
WINDS WILL REMAIN LIGHT AT THE SHELTERED IWD/SAW LOCATIONS. NO
CHANGES FROM PREVIOUS FORECAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 427 AM EST TUE FEB 7 2012
SINCE THE N WINDS EARLY THIS MORNING ARE NOT AS STRONG AS EARLIER
ANTICIPATED...GENERALLY NO HIER THAN 25 KT...CANX THE PREVIOUS HEAVY
FREEZING SPRAY WARNING THAT WAS IN EFFECT UNTIL 15Z FOR PORTIONS OF
CENTRAL LK SUP. WINDS TODAY WILL DIMINISH FURTHER WITH THE ARRIVAL
OF A HI PRES RDG/WEAKER PRES GRADIENT. ONCE THE HI CENTER DRIFTS
FARTHER S TONIGHT...A STRONGER W WIND UP TO 30 KTS WILL DEVELOP LATE
UNDER THE SHARPENING PRES GRADIENT BETWEEN THE RETREATING HI AND
FALLING PRES ACROSS ONTARIO. GRADIENT TIGHTENS FURTHER ON WEDNESDAY
WHICH COULD RESULT IN A FEW WESTERLY GALE GUSTS. WINDS BRIEFLY
DIMINISH LATER WEDNESDAY NIGHT INTO THURSDAY MORNING...BUT THEN
VEER NORTH AND INCREASE TO 30 KTS LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. HEAVY FREEZING SPRAY IS POSSIBLE THURSDAY NIGHT OVER
MUCH OF THE LAKE. EXPECT NORTH WINDS TO DIMINISH BLO 25 KTS LATER
FRIDAY WITH WINDS STAYING BLO 25 KTS THROUGH THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...07
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...07
MARINE...KC/JLA
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1141 AM EST TUE FEB 7 2012
.SYNOPSIS...
ISSUED AT 427 AM EST TUE FEB 7 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RATHER SHEARED
POSITIVELY TILTED SHRTWV DROPPING SEWD THRU THE UPR LKS IN
PREVAILING NW FLOW ALF BTWN TROF OVER QUEBEC AND UPR RDG OVER WRN
CAN. ACCOMPANYING SHARP COLD FNT THAT SURGED THRU THE FA YDAY HAS
NOW PUSHED TO THE S. ALTHOUGH MUCH COLDER AIR IS FOLLOWING THE FNT
WITH NNE FLOW AND 00Z H85 TEMPS RANGING FM 0C AT GRB TO -10C AT INL
AND -17C AT YPL...SGNFT LES HAS NOT DEVELOPED EVEN IN AREAS FAVORED
BY THE NNE FLOW. KEY FACTORS APPEAR TO BE IMPRESSIVE DRYING
REFLECTED BY 00Z YPL RAOB /00Z PWAT 0.06 INCH/ THAT IS STEADILY
ERODING THE BACK EDGE OF THE LK CLD AS SHOWN ON IR STLT IMAGERY...
SUBSIDENCE ASSOCIATED WITH FAIRLY VIGOROUS DNVA/CAD/DEEP LYR QVECTOR
DVGC IN THE WAKE OF THE SHRTWV THAT IS CAUSING THE LLVL FLOW TO
BECOME ACYC AND SINK INVRN BASE TO ARND H9 AS SHOWN ON THE 00Z INL
AND YPL RAOBS. UNDER SFC RDG AXIS IN ONTARIO EXTENDING E FM HI
CENTER NEAR LK WINNIPEG...SKIES ARE MOCLR...AND SFC TEMPS/DWPTS HAVE
FALLEN INTO THE ZERO TO -10F RANGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 427 AM EST TUE FEB 7 2012
TODAY...COLD NLY FLOW IS FCST TO PERSIST THRU THIS MRNG BEFORE HI
PRES CENTER BLDG FM LK WINNIPEG INTO MN CAUSES THE LLVL FLOW TO BACK
TO THE W BY LATE IN THE DAY. THE COLDEST MODELS...NOTABLY THE 00Z
CNDN AND LOW WRF-ARW...SHOW H85 TEMPS SINKING TO -15 TO -17C OVER
SCNTRL LK SUP THIS MRNG WHILE THE WARMER 00Z NAM/GFS INDICATE THESE
TEMPS WL FALL NO LOWER THAN -14C OR SO. THE DIFFERENCE APPEARS TO BE
RELATED TO THE INVRN HGT FCST...WITH THE WARMER MODELS INDICATING A
LOWER INVRN BASE AOB 3K FT /NAM/ AS COMPARED TO ARND 4K FT
/WRF-ARW/. SINCE DEEP LYR QVECTOR DVGC/SUBSIDENCE WL INTENSIFY THRU
THE DAY AND TRENDS ON OBSVD SKY COVER OVER LK SUP SUG THE INVRN IS
CRASHING...WL TEND TO FOLLOW THE WARMER/LO INVRN BASE DEPICTED BY
THE 00Z NAM. THIS MODEL SHOWS ALMOST NO PCPN EVEN IN THE N WIND SN
BELTS WITH DIFFLUENT FLOW/H925-85 DEWPT DEPRESSION AS HI AS 7-10C
EVEN OVER THE N WIND SN BELTS THAT WOULD OTRW BE FAVORED BY THE LLVL
FLOW. SO ALTHOUGH SOME LES IS LIKELY TO BREAK OUT IN THE NEXT FEW
HRS THRU 12Z WITH THE ARRIVAL OF COLDER AIR...ANY SN ACCUM SHOULD BE
NO MORE THAN ARND AN INCH EVEN OVER THE HIER TERRAIN. BACKING MORE
ACYC FLOW THIS AFTN WITH INVRN BASE REMAINING BLO 3K FT SHOULD
DIMINISH THE LES FURTHER. ALTHOUGH DAYTIME TEMPS WL BE JUST A BIT
BELOW NORMAL...RECENT WARMTH WL MAKE THE DAY FEEL EVEN COLDER...
ESPECIALLY THIS MRNG WITH A STEADY N WIND.
TNGT...SFC HI PRES RDG AXIS IS FCST TO BE NEARLY OVHD IN THE EVNG
BUT THEN SHIFT TO THE S. WITH CONTINUED SUBSIDENCE AND THE FLOW
BACKING TO THE W...EXPECT SKIES TO TURN MOCLR EXCEPT PERHAPS OVER
THE KEWEENAW AND NEAR LK SUP E OF MUNISING. PWAT IS FCST TO BE 0.10
INCH AT 00Z...SO EXPECT A QUICK FALL OF TEMP IN THE EVNG WITH LGT
WINDS...SO ACCELERATED EARLY FALL OF TEMP. ONCE THE RDG SHIFTS TO
THE S OVERNGT...A STRONGER WNW WIND WL DVLP...WITH H925 WINDS FCST
UP TO 30-35 KTS. RETAINED GOING FCST MIN TEMPS AOB THE LO END OF
GUIDANCE PER VERY DRY AIR/OBSVD CHILL UPSTREAM OVER THE MORE
SHELTERED SRN TIER. TEMPS WL BE QUITE A BIT WARMER NEAR THE MORE
EXPOSED LK SUP AND UNDER THE SHARPER PRES GRADIENT FARTHER N OF THE
RDG AXIS...ESPECIALLY OVER THE E WHERE SOME LO CLDS MAY LINGER NEAR
THE SHORE THRU THE NGT UNDER WNW H925 FLOW.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 427 AM EST TUE FEB 7 2012
TROUGH WILL BE EXITING INTO EASTERN CANADA TO START THE LONG TERM
WHICH ALLOWS FOR HEIGHTS TO RISE FM PLAINS INTO GREAT LAKES. AT THE
SFC...HIGH PRESSURE OVER THE PLAINS SLIDES SOUTH ON WEDNESDAY
ALLOWING FOR WESTERLY WINDS AT LOW-LEVELS OVR UPR LAKES INTO
WEDNESDAY NIGHT. WEST WINDS ALONG WITH JUST SCT MID CLOUDS RESULTED
IN RAISING MAX TEMPS TOWARD HIGHER END OF GUIDANCE /AROUND 30 INLAND
AND INTO THE MID 30S NEAR LK SUPERIOR/. NEXT COLD FRONT WILL BE
DROPPING SOUTH ACROSS ONTARIO ON WEDNESDAY NIGHT...SO EXPECT AT
LEAST LGT WEST WINDS TO PERSIST THROUGH THE NIGHT. INLAND AREAS
COULD TRY TO DECOUPLE AND FALL INTO THE TEENS...BUT TEMPS ALONG
SHORELINES OF LK SUPERIOR AND LK MICHIGAN SHOULD STAY IN THE MID TO
UPR 20S. FCST SOUNDINGS FM BOTH NAM AND GFS INDICATE CONDITIONS TOO
DRY TO SUPPORT ANY PCPN AHEAD OF THE FRONT IN THE WESTERLY FLOW.
HAVE REMOVED ANY MENTION OF SNOW UNTIL THURSDAY...EVEN OVR THE
KEWEENAW PENINSULA.
CHANGES BEGIN TO OCCUR LATER THURSDAY AS ARCTIC COLD FRONT IS FCST
TO ARRIVE. PROBABLY WILL SEE FALLING TEMPS...BUT AT THIS POINT STUCK
WITH NORMAL DIURNAL TEMP CURVE AS PRIMARY COOLING FM FROPA DOES NOT
OCCUR UNTIL LATE IN THE DAY. SOUNDINGS SHOW SUFFICIENT MOISTENING TO
JUSTIFY SOME SNOW SHOWERS BY LATE AFTN OVR KEWEENAW. ELSEWHERE...
CHANCES OF PCPN ON THURSDAY LOOK MINIMAL. LK EFFECT THEN BECOMES
MORE OF AN ISSUE BY THURSDAY EVENING AS NW WINDS IN BLYR VEER MORE
NORTHERLY. H85 TEMPS FALLING BLO -20C PER GFS/ECMWF LEAD TO SURGE OF
OVER-WATER INSTABILITY WITH LAKE EFFECT EQL AOA 8KFT AND SFC-H85
LAPSE RATES OVR 9C/KM. INSTABILITY IS SUPPLEMENTED BY MID LEVEL
MOISTURE /UP TO H7/. OVERALL SETUP APPEARS FAVORABLE FOR MODERATE
AND POSSIBLY HEAVY LK EFFECT SNOW SHOWERS THURSDAY NIGHT INTO
FRIDAY. SNOW WILL BE FLUFFY AS MAJORITY OF LAKE EFFECT CONVECTIVE
LAYER IS WITHIN THE DENDRITIC GROWTH ZONE. SLR/S FM COBB METHOD IN
BUFKIT RISE WELL ABOVE 20:1.
ONLY MAIN ISSUE TO SORT OUT STILL IS EXACT BLYR WIND DIRECTION. NAM
IS STRONGEST WITH SFC TROUGH AND ASSOCIATED NORTHEAST WINDS DEVELOPING
IN THE WAKE OF THE TROUGH. GFS/ECMWF ARE MORE NORTHERLY WITH THE
WINDS WHILE CANADIAN SHOWS WINDS REMAINING FM NORTHWEST. DO LIKE THE
NAM IDEA INDICATING SHARP WIND SHIFT JUST IN WAKE OF ARCTIC
FRONT...BUT WENT WITH BLEND OF NAM AND PREVIOUS FCST FOR THE WINDS.
RESULT OF THIS CHOICE WAS SOLN WITH WINDS THAT LOOKED LIKE LATEST
ECMWF. GIVEN FAVORABLE OVER-WATER INSTABILITY AND EXPECTED NORTHERLY
WINDS...INCREASED POPS TO LIKELY OVR NORTH WIND SNOW BELTS IN FAR
WEST AND NORTH CENTRAL UPR MI. SEVERAL INCHES OF SNOW SEEMS POSSIBLE
THURSDAY NIGHT INTO FRIDAY...AND WILL CONTINUE TO MENTION THIS IN
THE HAZARDOUS WEATHER OUTLOOK.
IN THE EXTENDED...AGREEMENT IN OVERALL IDEA THAT FIRST PORTION OF
THE WEEKEND WILL BE DOMINANTED BY LINGERING COLD AIRMASS /H85 TEMPS
AROUND -20C/ THAT MOVES IN LATE THIS WEEK. LK EFFECT IN NORTH TO
NORTHWEST FLOW AREAS FRIDAY AND FRIDAY NIGHT WILL DIMINISH ON
SATURDAY AS WINDS TURN MORE WESTERLY AHEAD OF YET ANOTHER COLD
FRONT. BOTH GFS/ECMWF POINT TO CENTER OF POLAR VORTEX WITH H85 TEMPS
NEAR -30C TO FINALLY COME SOUTH INTO GREAT LAKES BY SUNDAY. VORTEX
IS QUITE COMPACT THOUGH AND IT SEEMS DIFFICULT AT BEST TO FCST WHERE
THE CORE OF COLDEST AIR WILL ACTUALLY TRAVEL. GFS IS FARTHER WEST
AND WOULD RESULT IN MIN TEMPS ON SATURDAY NIGHT WELL BLO ZERO IN THE
CNTRL AND EAST. ECMWF IS FARTHER EAST WITH THE VORTEX. SEEMS LIKE
TREND THIS WINTER OF ONLY GLANCING BLOWS OF COLDER AIR OVR UPR LAKES
WOULD SUPPORT THE ECMWF IDEA.
LK EFFECT MAY KICK UP AGAIN LATE IN THE WEEKEND...THOUGH LOW
INVERSION HEIGHTS AND VERY DRY LOW-LEVELS WILL KEEP ACCUMS IN CHECK.
BLEND OF MODELS WORKS FOR NOW...WHICH RESULTED IN SLIGHT CHANCES FOR
SNOW SHOWERS. DUE TO FINE NATURE OF CRYSTALS/NEEDLES IN SUCH A COLD
AIRMASS...THE MAIN IMPACT FM THE SNOW SHOWERS WOULD BE REDUCED
VSBY...ESPECIALLY WITH SOME WIND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1140 AM EST TUE FEB 7 2012
EXPECT MVFR CIGS TO GIVE WAY TO CLEARING/VFR CONDITIONS THIS
AFTERNOON WITH THE ARRIVAL OF DRY LOW LEVEL AIR. AS A HIGH PRESSURE
RIDGE SINKS TO THE SOUTH TONIGHT...EXPECT A GUSTY W WIND AT CMX
UNDER SHARPER PRES GRADIENT ON THE MORE EXPOSED KEWEENAW PENINSULA.
WINDS WILL REMAIN LIGHT AT THE SHELTERED IWD/SAW LOCATIONS. NO
CHANGES FROM PREVIOUS FORECAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 427 AM EST TUE FEB 7 2012
SINCE THE N WINDS EARLY THIS MORNING ARE NOT AS STRONG AS EARLIER
ANTICIPATED...GENERALLY NO HIER THAN 25 KT...CANX THE PREVIOUS HEAVY
FREEZING SPRAY WARNING THAT WAS IN EFFECT UNTIL 15Z FOR PORTIONS OF
CENTRAL LK SUP. WINDS TODAY WILL DIMINISH FURTHER WITH THE ARRIVAL
OF A HI PRES RDG/WEAKER PRES GRADIENT. ONCE THE HI CENTER DRIFTS
FARTHER S TONIGHT...A STRONGER W WIND UP TO 30 KTS WILL DEVELOP LATE
UNDER THE SHARPENING PRES GRADIENT BETWEEN THE RETREATING HI AND
FALLING PRES ACROSS ONTARIO. GRADIENT TIGHTENS FURTHER ON WEDNESDAY
WHICH COULD RESULT IN A FEW WESTERLY GALE GUSTS. WINDS BRIEFLY
DIMINISH LATER WEDNESDAY NIGHT INTO THURSDAY MORNING...BUT THEN
VEER NORTH AND INCREASE TO 30 KTS LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. HEAVY FREEZING SPRAY IS POSSIBLE THURSDAY NIGHT OVER
MUCH OF THE LAKE. EXPECT NORTH WINDS TO DIMINISH BLO 25 KTS LATER
FRIDAY WITH WINDS STAYING BLO 25 KTS THROUGH THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...07
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
625 AM EST TUE FEB 7 2012
.SYNOPSIS...
ISSUED AT 427 AM EST TUE FEB 7 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RATHER SHEARED
POSITIVELY TILTED SHRTWV DROPPING SEWD THRU THE UPR LKS IN
PREVAILING NW FLOW ALF BTWN TROF OVER QUEBEC AND UPR RDG OVER WRN
CAN. ACCOMPANYING SHARP COLD FNT THAT SURGED THRU THE FA YDAY HAS
NOW PUSHED TO THE S. ALTHOUGH MUCH COLDER AIR IS FOLLOWING THE FNT
WITH NNE FLOW AND 00Z H85 TEMPS RANGING FM 0C AT GRB TO -10C AT INL
AND -17C AT YPL...SGNFT LES HAS NOT DEVELOPED EVEN IN AREAS FAVORED
BY THE NNE FLOW. KEY FACTORS APPEAR TO BE IMPRESSIVE DRYING
REFLECTED BY 00Z YPL RAOB /00Z PWAT 0.06 INCH/ THAT IS STEADILY
ERODING THE BACK EDGE OF THE LK CLD AS SHOWN ON IR STLT IMAGERY...
SUBSIDENCE ASSOCIATED WITH FAIRLY VIGOROUS DNVA/CAD/DEEP LYR QVECTOR
DVGC IN THE WAKE OF THE SHRTWV THAT IS CAUSING THE LLVL FLOW TO
BECOME ACYC AND SINK INVRN BASE TO ARND H9 AS SHOWN ON THE 00Z INL
AND YPL RAOBS. UNDER SFC RDG AXIS IN ONTARIO EXTENDING E FM HI
CENTER NEAR LK WINNIPEG...SKIES ARE MOCLR...AND SFC TEMPS/DWPTS HAVE
FALLEN INTO THE ZERO TO -10F RANGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 427 AM EST TUE FEB 7 2012
TODAY...COLD NLY FLOW IS FCST TO PERSIST THRU THIS MRNG BEFORE HI
PRES CENTER BLDG FM LK WINNIPEG INTO MN CAUSES THE LLVL FLOW TO BACK
TO THE W BY LATE IN THE DAY. THE COLDEST MODELS...NOTABLY THE 00Z
CNDN AND LOW WRF-ARW...SHOW H85 TEMPS SINKING TO -15 TO -17C OVER
SCNTRL LK SUP THIS MRNG WHILE THE WARMER 00Z NAM/GFS INDICATE THESE
TEMPS WL FALL NO LOWER THAN -14C OR SO. THE DIFFERENCE APPEARS TO BE
RELATED TO THE INVRN HGT FCST...WITH THE WARMER MODELS INDICATING A
LOWER INVRN BASE AOB 3K FT /NAM/ AS COMPARED TO ARND 4K FT
/WRF-ARW/. SINCE DEEP LYR QVECTOR DVGC/SUBSIDENCE WL INTENSIFY THRU
THE DAY AND TRENDS ON OBSVD SKY COVER OVER LK SUP SUG THE INVRN IS
CRASHING...WL TEND TO FOLLOW THE WARMER/LO INVRN BASE DEPICTED BY
THE 00Z NAM. THIS MODEL SHOWS ALMOST NO PCPN EVEN IN THE N WIND SN
BELTS WITH DIFFLUENT FLOW/H925-85 DEWPT DEPRESSION AS HI AS 7-10C
EVEN OVER THE N WIND SN BELTS THAT WOULD OTRW BE FAVORED BY THE LLVL
FLOW. SO ALTHOUGH SOME LES IS LIKELY TO BREAK OUT IN THE NEXT FEW
HRS THRU 12Z WITH THE ARRIVAL OF COLDER AIR...ANY SN ACCUM SHOULD BE
NO MORE THAN ARND AN INCH EVEN OVER THE HIER TERRAIN. BACKING MORE
ACYC FLOW THIS AFTN WITH INVRN BASE REMAINING BLO 3K FT SHOULD
DIMINISH THE LES FURTHER. ALTHOUGH DAYTIME TEMPS WL BE JUST A BIT
BELOW NORMAL...RECENT WARMTH WL MAKE THE DAY FEEL EVEN COLDER...
ESPECIALLY THIS MRNG WITH A STEADY N WIND.
TNGT...SFC HI PRES RDG AXIS IS FCST TO BE NEARLY OVHD IN THE EVNG
BUT THEN SHIFT TO THE S. WITH CONTINUED SUBSIDENCE AND THE FLOW
BACKING TO THE W...EXPECT SKIES TO TURN MOCLR EXCEPT PERHAPS OVER
THE KEWEENAW AND NEAR LK SUP E OF MUNISING. PWAT IS FCST TO BE 0.10
INCH AT 00Z...SO EXPECT A QUICK FALL OF TEMP IN THE EVNG WITH LGT
WINDS...SO ACCELERATED EARLY FALL OF TEMP. ONCE THE RDG SHIFTS TO
THE S OVERNGT...A STRONGER WNW WIND WL DVLP...WITH H925 WINDS FCST
UP TO 30-35 KTS. RETAINED GOING FCST MIN TEMPS AOB THE LO END OF
GUIDANCE PER VERY DRY AIR/OBSVD CHILL UPSTREAM OVER THE MORE
SHELTERED SRN TIER. TEMPS WL BE QUITE A BIT WARMER NEAR THE MORE
EXPOSED LK SUP AND UNDER THE SHARPER PRES GRADIENT FARTHER N OF THE
RDG AXIS...ESPECIALLY OVER THE E WHERE SOME LO CLDS MAY LINGER NEAR
THE SHORE THRU THE NGT UNDER WNW H925 FLOW.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 427 AM EST TUE FEB 7 2012
TROUGH WILL BE EXITING INTO EASTERN CANADA TO START THE LONG TERM
WHICH ALLOWS FOR HEIGHTS TO RISE FM PLAINS INTO GREAT LAKES. AT THE
SFC...HIGH PRESSURE OVER THE PLAINS SLIDES SOUTH ON WEDNESDAY
ALLOWING FOR WESTERLY WINDS AT LOW-LEVELS OVR UPR LAKES INTO
WEDNESDAY NIGHT. WEST WINDS ALONG WITH JUST SCT MID CLOUDS RESULTED
IN RAISING MAX TEMPS TOWARD HIGHER END OF GUIDANCE /AROUND 30 INLAND
AND INTO THE MID 30S NEAR LK SUPERIOR/. NEXT COLD FRONT WILL BE
DROPPING SOUTH ACROSS ONTARIO ON WEDNESDAY NIGHT...SO EXPECT AT
LEAST LGT WEST WINDS TO PERSIST THROUGH THE NIGHT. INLAND AREAS
COULD TRY TO DECOUPLE AND FALL INTO THE TEENS...BUT TEMPS ALONG
SHORELINES OF LK SUPERIOR AND LK MICHIGAN SHOULD STAY IN THE MID TO
UPR 20S. FCST SOUNDINGS FM BOTH NAM AND GFS INDICATE CONDITIONS TOO
DRY TO SUPPORT ANY PCPN AHEAD OF THE FRONT IN THE WESTERLY FLOW.
HAVE REMOVED ANY MENTION OF SNOW UNTIL THURSDAY...EVEN OVR THE
KEWEENAW PENINSULA.
CHANGES BEGIN TO OCCUR LATER THURSDAY AS ARCTIC COLD FRONT IS FCST
TO ARRIVE. PROBABLY WILL SEE FALLING TEMPS...BUT AT THIS POINT STUCK
WITH NORMAL DIURNAL TEMP CURVE AS PRIMARY COOLING FM FROPA DOES NOT
OCCUR UNTIL LATE IN THE DAY. SOUNDINGS SHOW SUFFICIENT MOISTENING TO
JUSTIFY SOME SNOW SHOWERS BY LATE AFTN OVR KEWEENAW. ELSEWHERE...
CHANCES OF PCPN ON THURSDAY LOOK MINIMAL. LK EFFECT THEN BECOMES
MORE OF AN ISSUE BY THURSDAY EVENING AS NW WINDS IN BLYR VEER MORE
NORTHERLY. H85 TEMPS FALLING BLO -20C PER GFS/ECMWF LEAD TO SURGE OF
OVER-WATER INSTABILITY WITH LAKE EFFECT EQL AOA 8KFT AND SFC-H85
LAPSE RATES OVR 9C/KM. INSTABILITY IS SUPPLEMENTED BY MID LEVEL
MOISTURE /UP TO H7/. OVERALL SETUP APPEARS FAVORABLE FOR MODERATE
AND POSSIBLY HEAVY LK EFFECT SNOW SHOWERS THURSDAY NIGHT INTO
FRIDAY. SNOW WILL BE FLUFFY AS MAJORITY OF LAKE EFFECT CONVECTIVE
LAYER IS WITHIN THE DENDRITIC GROWTH ZONE. SLR/S FM COBB METHOD IN
BUFKIT RISE WELL ABOVE 20:1.
ONLY MAIN ISSUE TO SORT OUT STILL IS EXACT BLYR WIND DIRECTION. NAM
IS STRONGEST WITH SFC TROUGH AND ASSOCIATED NORTHEAST WINDS DEVELOPING
IN THE WAKE OF THE TROUGH. GFS/ECMWF ARE MORE NORTHERLY WITH THE
WINDS WHILE CANADIAN SHOWS WINDS REMAINING FM NORTHWEST. DO LIKE THE
NAM IDEA INDICATING SHARP WIND SHIFT JUST IN WAKE OF ARCTIC
FRONT...BUT WENT WITH BLEND OF NAM AND PREVIOUS FCST FOR THE WINDS.
RESULT OF THIS CHOICE WAS SOLN WITH WINDS THAT LOOKED LIKE LATEST
ECMWF. GIVEN FAVORABLE OVER-WATER INSTABILITY AND EXPECTED NORTHERLY
WINDS...INCREASED POPS TO LIKELY OVR NORTH WIND SNOW BELTS IN FAR
WEST AND NORTH CENTRAL UPR MI. SEVERAL INCHES OF SNOW SEEMS POSSIBLE
THURSDAY NIGHT INTO FRIDAY...AND WILL CONTINUE TO MENTION THIS IN
THE HAZARDOUS WEATHER OUTLOOK.
IN THE EXTENDED...AGREEMENT IN OVERALL IDEA THAT FIRST PORTION OF
THE WEEKEND WILL BE DOMINANTED BY LINGERING COLD AIRMASS /H85 TEMPS
AROUND -20C/ THAT MOVES IN LATE THIS WEEK. LK EFFECT IN NORTH TO
NORTHWEST FLOW AREAS FRIDAY AND FRIDAY NIGHT WILL DIMINISH ON
SATURDAY AS WINDS TURN MORE WESTERLY AHEAD OF YET ANOTHER COLD
FRONT. BOTH GFS/ECMWF POINT TO CENTER OF POLAR VORTEX WITH H85 TEMPS
NEAR -30C TO FINALLY COME SOUTH INTO GREAT LAKES BY SUNDAY. VORTEX
IS QUITE COMPACT THOUGH AND IT SEEMS DIFFICULT AT BEST TO FCST WHERE
THE CORE OF COLDEST AIR WILL ACTUALLY TRAVEL. GFS IS FARTHER WEST
AND WOULD RESULT IN MIN TEMPS ON SATURDAY NIGHT WELL BLO ZERO IN THE
CNTRL AND EAST. ECMWF IS FARTHER EAST WITH THE VORTEX. SEEMS LIKE
TREND THIS WINTER OF ONLY GLANCING BLOWS OF COLDER AIR OVR UPR LAKES
WOULD SUPPORT THE ECMWF IDEA.
LK EFFECT MAY KICK UP AGAIN LATE IN THE WEEKEND...THOUGH LOW
INVERSION HEIGHTS AND VERY DRY LOW-LEVELS WILL KEEP ACCUMS IN CHECK.
BLEND OF MODELS WORKS FOR NOW...WHICH RESULTED IN SLIGHT CHANCES FOR
SNOW SHOWERS. DUE TO FINE NATURE OF CRYSTALS/NEEDLES IN SUCH A COLD
AIRMASS...THE MAIN IMPACT FM THE SNOW SHOWERS WOULD BE REDUCED
VSBY...ESPECIALLY WITH SOME WIND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 624 AM EST TUE FEB 7 2012
EXPECT MVFR CIGS TO GIVE WAY TO CLRG/VFR CONDITIONS THIS AFTN WITH
THE ARRIVAL OF A HI PRES RIDGE/VERY DRY LLVL AIR. AS THE HI PRES RDG
SINKS TO THE S TNGT...EXPECT A GUSTY W WIND AT CMX UNDER SHARPER
PRES GRADIENT ON THE MORE EXPOSED KEWEENAW PENINSULA. WINDS WL
REMAIN LGT AT THE SHELTERED IWD/SAW LOCATIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 427 AM EST TUE FEB 7 2012
SINCE THE N WINDS EARLY THIS MORNING ARE NOT AS STRONG AS EARLIER
ANTICIPATED...GENERALLY NO HIER THAN 25 KT...CANX THE PREVIOUS HEAVY
FREEZING SPRAY WARNING THAT WAS IN EFFECT UNTIL 15Z FOR PORTIONS OF
CENTRAL LK SUP. WINDS TODAY WILL DIMINISH FURTHER WITH THE ARRIVAL
OF A HI PRES RDG/WEAKER PRES GRADIENT. ONCE THE HI CENTER DRIFTS
FARTHER S TONIGHT...A STRONGER W WIND UP TO 30 KTS WILL DEVELOP LATE
UNDER THE SHARPENING PRES GRADIENT BETWEEN THE RETREATING HI AND
FALLING PRES ACROSS ONTARIO. GRADIENT TIGHTENS FURTHER ON WEDNESDAY
WHICH COULD RESULT IN A FEW WESTERLY GALE GUSTS. WINDS BRIEFLY
DIMINISH LATER WEDNESDAY NIGHT INTO THURSDAY MORNING...BUT THEN
VEER NORTH AND INCREASE TO 30 KTS LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. HEAVY FREEZING SPRAY IS POSSIBLE THURSDAY NIGHT OVER
MUCH OF THE LAKE. EXPECT NORTH WINDS TO DIMINISH BLO 25 KTS LATER
FRIDAY WITH WINDS STAYING BLO 25 KTS THROUGH THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
434 AM EST TUE FEB 7 2012
.SYNOPSIS...
ISSUED AT 427 AM EST TUE FEB 7 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RATHER SHEARED
POSITIVELY TILTED SHRTWV DROPPING SEWD THRU THE UPR LKS IN
PREVAILING NW FLOW ALF BTWN TROF OVER QUEBEC AND UPR RDG OVER WRN
CAN. ACCOMPANYING SHARP COLD FNT THAT SURGED THRU THE FA YDAY HAS
NOW PUSHED TO THE S. ALTHOUGH MUCH COLDER AIR IS FOLLOWING THE FNT
WITH NNE FLOW AND 00Z H85 TEMPS RANGING FM 0C AT GRB TO -10C AT INL
AND -17C AT YPL...SGNFT LES HAS NOT DEVELOPED EVEN IN AREAS FAVORED
BY THE NNE FLOW. KEY FACTORS APPEAR TO BE IMPRESSIVE DRYING
REFLECTED BY 00Z YPL RAOB /00Z PWAT 0.06 INCH/ THAT IS STEADILY
ERODING THE BACK EDGE OF THE LK CLD AS SHOWN ON IR STLT IMAGERY...
SUBSIDENCE ASSOCIATED WITH FAIRLY VIGOROUS DNVA/CAD/DEEP LYR QVECTOR
DVGC IN THE WAKE OF THE SHRTWV THAT IS CAUSING THE LLVL FLOW TO
BECOME ACYC AND SINK INVRN BASE TO ARND H9 AS SHOWN ON THE 00Z INL
AND YPL RAOBS. UNDER SFC RDG AXIS IN ONTARIO EXTENDING E FM HI
CENTER NEAR LK WINNIPEG...SKIES ARE MOCLR...AND SFC TEMPS/DWPTS HAVE
FALLEN INTO THE ZERO TO -10F RANGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 427 AM EST TUE FEB 7 2012
TODAY...COLD NLY FLOW IS FCST TO PERSIST THRU THIS MRNG BEFORE HI
PRES CENTER BLDG FM LK WINNIPEG INTO MN CAUSES THE LLVL FLOW TO BACK
TO THE W BY LATE IN THE DAY. THE COLDEST MODELS...NOTABLY THE 00Z
CNDN AND LOW WRF-ARW...SHOW H85 TEMPS SINKING TO -15 TO -17C OVER
SCNTRL LK SUP THIS MRNG WHILE THE WARMER 00Z NAM/GFS INDICATE THESE
TEMPS WL FALL NO LOWER THAN -14C OR SO. THE DIFFERENCE APPEARS TO BE
RELATED TO THE INVRN HGT FCST...WITH THE WARMER MODELS INDICATING A
LOWER INVRN BASE AOB 3K FT /NAM/ AS COMPARED TO ARND 4K FT
/WRF-ARW/. SINCE DEEP LYR QVECTOR DVGC/SUBSIDENCE WL INTENSIFY THRU
THE DAY AND TRENDS ON OBSVD SKY COVER OVER LK SUP SUG THE INVRN IS
CRASHING...WL TEND TO FOLLOW THE WARMER/LO INVRN BASE DEPICTED BY
THE 00Z NAM. THIS MODEL SHOWS ALMOST NO PCPN EVEN IN THE N WIND SN
BELTS WITH DIFFLUENT FLOW/H925-85 DEWPT DEPRESSION AS HI AS 7-10C
EVEN OVER THE N WIND SN BELTS THAT WOULD OTRW BE FAVORED BY THE LLVL
FLOW. SO ALTHOUGH SOME LES IS LIKELY TO BREAK OUT IN THE NEXT FEW
HRS THRU 12Z WITH THE ARRIVAL OF COLDER AIR...ANY SN ACCUM SHOULD BE
NO MORE THAN ARND AN INCH EVEN OVER THE HIER TERRAIN. BACKING MORE
ACYC FLOW THIS AFTN WITH INVRN BASE REMAINING BLO 3K FT SHOULD
DIMINISH THE LES FURTHER. ALTHOUGH DAYTIME TEMPS WL BE JUST A BIT
BELOW NORMAL...RECENT WARMTH WL MAKE THE DAY FEEL EVEN COLDER...
ESPECIALLY THIS MRNG WITH A STEADY N WIND.
TNGT...SFC HI PRES RDG AXIS IS FCST TO BE NEARLY OVHD IN THE EVNG
BUT THEN SHIFT TO THE S. WITH CONTINUED SUBSIDENCE AND THE FLOW
BACKING TO THE W...EXPECT SKIES TO TURN MOCLR EXCEPT PERHAPS OVER
THE KEWEENAW AND NEAR LK SUP E OF MUNISING. PWAT IS FCST TO BE 0.10
INCH AT 00Z...SO EXPECT A QUICK FALL OF TEMP IN THE EVNG WITH LGT
WINDS...SO ACCELERATED EARLY FALL OF TEMP. ONCE THE RDG SHIFTS TO
THE S OVERNGT...A STRONGER WNW WIND WL DVLP...WITH H925 WINDS FCST
UP TO 30-35 KTS. RETAINED GOING FCST MIN TEMPS AOB THE LO END OF
GUIDANCE PER VERY DRY AIR/OBSVD CHILL UPSTREAM OVER THE MORE
SHELTERED SRN TIER. TEMPS WL BE QUITE A BIT WARMER NEAR THE MORE
EXPOSED LK SUP AND UNDER THE SHARPER PRES GRADIENT FARTHER N OF THE
RDG AXIS...ESPECIALLY OVER THE E WHERE SOME LO CLDS MAY LINGER NEAR
THE SHORE THRU THE NGT UNDER WNW H925 FLOW.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 427 AM EST TUE FEB 7 2012
TROUGH WILL BE EXITING INTO EASTERN CANADA TO START THE LONG TERM
WHICH ALLOWS FOR HEIGHTS TO RISE FM PLAINS INTO GREAT LAKES. AT THE
SFC...HIGH PRESSURE OVER THE PLAINS SLIDES SOUTH ON WEDNESDAY
ALLOWING FOR WESTERLY WINDS AT LOW-LEVELS OVR UPR LAKES INTO
WEDNESDAY NIGHT. WEST WINDS ALONG WITH JUST SCT MID CLOUDS RESULTED
IN RAISING MAX TEMPS TOWARD HIGHER END OF GUIDANCE /AROUND 30 INLAND
AND INTO THE MID 30S NEAR LK SUPERIOR/. NEXT COLD FRONT WILL BE
DROPPING SOUTH ACROSS ONTARIO ON WEDNESDAY NIGHT...SO EXPECT AT
LEAST LGT WEST WINDS TO PERSIST THROUGH THE NIGHT. INLAND AREAS
COULD TRY TO DECOUPLE AND FALL INTO THE TEENS...BUT TEMPS ALONG
SHORELINES OF LK SUPERIOR AND LK MICHIGAN SHOULD STAY IN THE MID TO
UPR 20S. FCST SOUNDINGS FM BOTH NAM AND GFS INDICATE CONDITIONS TOO
DRY TO SUPPORT ANY PCPN AHEAD OF THE FRONT IN THE WESTERLY FLOW.
HAVE REMOVED ANY MENTION OF SNOW UNTIL THURSDAY...EVEN OVR THE
KEWEENAW PENINSULA.
CHANGES BEGIN TO OCCUR LATER THURSDAY AS ARCTIC COLD FRONT IS FCST
TO ARRIVE. PROBABLY WILL SEE FALLING TEMPS...BUT AT THIS POINT STUCK
WITH NORMAL DIURNAL TEMP CURVE AS PRIMARY COOLING FM FROPA DOES NOT
OCCUR UNTIL LATE IN THE DAY. SOUNDINGS SHOW SUFFICIENT MOISTENING TO
JUSTIFY SOME SNOW SHOWERS BY LATE AFTN OVR KEWEENAW. ELSEWHERE...
CHANCES OF PCPN ON THURSDAY LOOK MINIMAL. LK EFFECT THEN BECOMES
MORE OF AN ISSUE BY THURSDAY EVENING AS NW WINDS IN BLYR VEER MORE
NORTHERLY. H85 TEMPS FALLING BLO -20C PER GFS/ECMWF LEAD TO SURGE OF
OVER-WATER INSTABILITY WITH LAKE EFFECT EQL AOA 8KFT AND SFC-H85
LAPSE RATES OVR 9C/KM. INSTABILITY IS SUPPLEMENTED BY MID LEVEL
MOISTURE /UP TO H7/. OVERALL SETUP APPEARS FAVORABLE FOR MODERATE
AND POSSIBLY HEAVY LK EFFECT SNOW SHOWERS THURSDAY NIGHT INTO
FRIDAY. SNOW WILL BE FLUFFY AS MAJORITY OF LAKE EFFECT CONVECTIVE
LAYER IS WITHIN THE DENDRITIC GROWTH ZONE. SLR/S FM COBB METHOD IN
BUFKIT RISE WELL ABOVE 20:1.
ONLY MAIN ISSUE TO SORT OUT STILL IS EXACT BLYR WIND DIRECTION. NAM
IS STRONGEST WITH SFC TROUGH AND ASSOCIATED NORTHEAST WINDS DEVELOPING
IN THE WAKE OF THE TROUGH. GFS/ECMWF ARE MORE NORTHERLY WITH THE
WINDS WHILE CANADIAN SHOWS WINDS REMAINING FM NORTHWEST. DO LIKE THE
NAM IDEA INDICATING SHARP WIND SHIFT JUST IN WAKE OF ARCTIC
FRONT...BUT WENT WITH BLEND OF NAM AND PREVIOUS FCST FOR THE WINDS.
RESULT OF THIS CHOICE WAS SOLN WITH WINDS THAT LOOKED LIKE LATEST
ECMWF. GIVEN FAVORABLE OVER-WATER INSTABILITY AND EXPECTED NORTHERLY
WINDS...INCREASED POPS TO LIKELY OVR NORTH WIND SNOW BELTS IN FAR
WEST AND NORTH CENTRAL UPR MI. SEVERAL INCHES OF SNOW SEEMS POSSIBLE
THURSDAY NIGHT INTO FRIDAY...AND WILL CONTINUE TO MENTION THIS IN
THE HAZARDOUS WEATHER OUTLOOK.
IN THE EXTENDED...AGREEMENT IN OVERALL IDEA THAT FIRST PORTION OF
THE WEEKEND WILL BE DOMINANTED BY LINGERING COLD AIRMASS /H85 TEMPS
AROUND -20C/ THAT MOVES IN LATE THIS WEEK. LK EFFECT IN NORTH TO
NORTHWEST FLOW AREAS FRIDAY AND FRIDAY NIGHT WILL DIMINISH ON
SATURDAY AS WINDS TURN MORE WESTERLY AHEAD OF YET ANOTHER COLD
FRONT. BOTH GFS/ECMWF POINT TO CENTER OF POLAR VORTEX WITH H85 TEMPS
NEAR -30C TO FINALLY COME SOUTH INTO GREAT LAKES BY SUNDAY. VORTEX
IS QUITE COMPACT THOUGH AND IT SEEMS DIFFICULT AT BEST TO FCST WHERE
THE CORE OF COLDEST AIR WILL ACTUALLY TRAVEL. GFS IS FARTHER WEST
AND WOULD RESULT IN MIN TEMPS ON SATURDAY NIGHT WELL BLO ZERO IN THE
CNTRL AND EAST. ECMWF IS FARTHER EAST WITH THE VORTEX. SEEMS LIKE
TREND THIS WINTER OF ONLY GLANCING BLOWS OF COLDER AIR OVR UPR LAKES
WOULD SUPPORT THE ECMWF IDEA.
LK EFFECT MAY KICK UP AGAIN LATE IN THE WEEKEND...THOUGH LOW
INVERSION HEIGHTS AND VERY DRY LOW-LEVELS WILL KEEP ACCUMS IN CHECK.
BLEND OF MODELS WORKS FOR NOW...WHICH RESULTED IN SLIGHT CHANCES FOR
SNOW SHOWERS. DUE TO FINE NATURE OF CRYSTALS/NEEDLES IN SUCH A COLD
AIRMASS...THE MAIN IMPACT FM THE SNOW SHOWERS WOULD BE REDUCED
VSBY...ESPECIALLY WITH SOME WIND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z EARLY WEDNESDAY MORNING)
ISSUED AT 427 AM EST TUE FEB 7 2012
LIGHT LES AND MVFR CIGS WILL CONTINUE INTO TUE MORNING WITH N-NE
FLOW ACROSS THE AREA. UPSLOPE NNE FLOW WILL FAVOR KSAW FOR LOWER
VSBYS IN LES...BUT GENERALLY EXPECT VSBYS AT KSAW TO STAY IN THE
MVFR RANGE. DIMINISHING TREND TO LAKE EFFECT SHSN AND IMPROVEMENT IS
EXPECTED AT ALL SITES BY LATE TUE MORNING AS FLOW BECOMES
INCREASINGLY ANTICYCLONIC...THE SUBSIDENCE INVERSION LOWERS AND
DRIER AIR ARRIVES. EXPECT CLEARING FROM THE WEST BY MID-LATE TUE
AFTERNOON AS FLOW BACKS MORE NW WITH VFR CONDITIONS TO CONTINUE INTO
TUE EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 427 AM EST TUE FEB 7 2012
SINCE THE N WINDS EARLY THIS MORNING ARE NOT AS STRONG AS EARLIER
ANTICIPATED...GENERALLY NO HIER THAN 25 KT...CANX THE PREVIOUS HEAVY
FREEZING SPRAY WARNING THAT WAS IN EFFECT UNTIL 15Z FOR PORTIONS OF
CENTRAL LK SUP. WINDS TODAY WILL DIMINISH FURTHER WITH THE ARRIVAL
OF A HI PRES RDG/WEAKER PRES GRADIENT. ONCE THE HI CENTER DRIFTS
FARTHER S TONIGHT...A STRONGER W WIND UP TO 30 KTS WILL DEVELOP LATE
UNDER THE SHARPENING PRES GRADIENT BETWEEN THE RETREATING HI AND
FALLING PRES ACROSS ONTARIO. GRADIENT TIGHTENS FURTHER ON WEDNESDAY
WHICH COULD RESULT IN A FEW WESTERLY GALE GUSTS. WINDS BRIEFLY
DIMINISH LATER WEDNESDAY NIGHT INTO THURSDAY MORNING...BUT THEN
VEER NORTH AND INCREASE TO 30 KTS LATE THURSDAY AFTERNOON INTO
THURSDAY NIGHT. HEAVY FREEZING SPRAY IS POSSIBLE THURSDAY NIGHT OVER
MUCH OF THE LAKE. EXPECT NORTH WINDS TO DIMINISH BLO 25 KTS LATER
FRIDAY WITH WINDS STAYING BLO 25 KTS THROUGH THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS GLASGOW MT
916 AM MST TUE FEB 7 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
LOW CLOUDS AND ISOLATED FLURRIES CONTINUE OVER THE NORTHEAST
MONTANA THIS MORNING. BACK EDGE OF THE CLOUDS STILL BACK IN
ALBERTA BUT NOT MOVING MUCH...SO HAVE EXTENDED FLURRIES INTO THE
AFTERNOON. WITH THE CLOUDS HANGING AROUND EXPECTED TEMPERATURES TO
NOT SHOW MUCH CHANGE SO ALSO LOWERED FORECAST MAXT. EBERT
PREVIOUS SHORT TERM DISCUSSION...1040 MB SURFACE HIGH CENTERED
OVER CENTRAL SK THE MAIN INFLUENCE ON OUR WEATHER AS IT MOVES
SLOWLY SSE. TEMPS NOT PARTICULARLY COLD WITH THIS.
NE FLOW AND RESULTING UPSLOPE INFLUENCED STRATUS COVERS ALL OF NE
MT...W ND...AND MOST OF S SK. THIS HAS PROVED A MAJOR FORECAST
BUGABOO. MOST MODELS HAVE BEEN OF LITTLE HELP AND WAY TOO FAST IN
CLEARING THE STRATUS OUT. SATELLITE FOG LOOP SHOWS THE STRATUS NOT
MOVING OR CHANGING MUCH. AT THIS RATE...WILL HAVE TO KEEP SKIES CLOUDY
THROUGH MOST OF THE DAY. DO EXPECT SOME CLEARING TO START SHOWING
IN TOUR N THIS AFTERNOON. AS THE SURFACE HIGH MOVES NEAREST TO US
AND THEN SE...IT SHOULD CLEAR ALL STRATUS OUT THIS EVENING. WILL CONFINE
FLURRY MENTION TO OUR EXTREME SW WHERE THERE ARE LAYERED HIGHER
CLOUD STILL ABOVE THE STRATUS.
OVERCAST HELD LOWS UP 10F OR MORE THAN EXPECTED LAST NIGHT.
HOWEVER WITH THE STRATUS STICKING AROUND MOST OF THE DAY...AND
COLDER PART OF THE AIRMASS NOW OVER US...HIGHS WON`T BE VERY MUCH
WARMER THAN THIS MORNINGS LOWS. COLDER TONIGHT THOUGH WITH
CLEARING SKIES FINALLY.
REX BLOCK UPPER PATTERN HAS BEEN BREAKING DOWN. UPPER RIDGE WILL
SHIFT AROUND A LITTLE...BUILDING STRONGLY N OVER THE PACIFIC COAST
STATES AND BC. THIS WILL INCREASE THE NNW FLOW ALOFT OVER OUR AREA
BETWEEN HE RIDGE AND THE HUDSON BAY LOW.
THE CANADIAN HIGH PRESSURE MOVES SE OUT OF THE AREA WED...ALLOWING
FOR SOME WARMING UNDER SUNNY SKIES. MODELS HAVE BEEN TRENDING
SLOWER WITH THE NEXT COLD FRONT THAT ARRIVES IN THE NNW FLOW...NOW
MOVING THRU THE CWA THURSDAY. 850 MB WINDS INCREASE TO AS HIGH AS
40KT 12-15Z. MODEL FORECAST SOUNDINGS ARE JUST SHORT OF DRY
ADIABATIC MIXED TO AROUND 900 MB AT THAT TIME AS MODERATE COLD
ADVECTION STARTS IN OUR N. SO TIMING NOT QUITE IDEAL TO MIX
MAXIMUM WINDS TO SURFACE...BUT IT WILL BE WINDY. AS WE MIX DRY
ADIABATICALLY TO ABOVE 900 MB IN THE AFTERNOON...WINDS AT THAT
LEVEL ARE LESS THEN. ANOTHER DRY COLD FRONT. MODELS INDICATE THERE
WILL BE JUST A SHORTLIVED NARROW BAND OF STRATUS BEHIND THE FRONT. SIMONSEN
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED BEGINS WITH HIGH PRESSURE OVER MANITOBA AND A
STATIONARY FRONT UP AGAINST THE ROCKY MOUNTAIN FRONT RANGE. MODELS
IN FAIR AGREEMENT WITH THIS SOLUTION FOR THE START OF THE PERIOD
FRIDAY MORNING.
FRIDAY THROUGH THE WEEKEND THE UPPER LOW OVER HUDSON BAY MOVES
INTO QUEBEC DRAGGING THE HIGH PRESSURE SYSTEM OVER MANITOBA SOUTH
AND EAST TOWARDS THE GREAT LAKES. THE NEXT EFFECT WILL BE A
WARMING TREND FOR NORTHEAST MONTANA. THE STATIONARY FRONT WILL
BECOME MORE OF A LEE TROUGH AND COULD PROVIDE A FOCUS OVER THE FAR
WESTERN ZONES FOR SOME VERY LIGHT PRECIPITATION. WILL KEEP THE
MENTION OF PRECIPITATION OUT FOR THE ZONES AT THIS TIME.
EARLY NEXT WEEK...THE EC AND GFS BRING AN UPPER LEVEL LOW THROUGH
NORTHEAST MONTANA AT DIFFERENT TIME STEPS... FOR NOW WILL JUST
KEEP SLIGHT CHANCE POPS IN THE FORECAST UNTIL THE MODELS COME
TOGETHER WITH FUTURE RUNS. PROTON
&&
.AVIATION...
A VERY PERSISTENT MVFR STRATUS DECK IS HOLDING OVER THE REGION. DO
EXPECT THE MVFR CEILINGS TO CONTINUE FOR ALL TAF SITES THROUGH 18Z. THE
CEILINGS SHOULD SLOWLY BREAK UP AFTER THAT. FOLLOWING THE HRRR AND
SREF GUIDANCE THIS MORNING SINCE THE MOS PRODUCTS HAVE HANDLED
THIS EVENT POORLY. PROTON/BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
358 AM MST TUE FEB 7 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
1040 MB SURFACE HIGH CENTERED OVER CENTRAL SK THE MAIN INFLUENCE
ON OUR WEATHER AS IT MOVES SLOWLY SSE. TEMPS NOT PARTICULARLY
COLD WITH THIS.
NE FLOW AND RESULTING UPSLOPE INFLUENCED STRATUS COVERS ALL OF NE
MT...W ND...AND MOST OF S SK. THIS HAS PROVED A MAJOR FORECAST
BUGABOO. MOST MODELS HAVE BEEN OF LITTLE HELP AND WAY TOO FAST IN
CLEARING THE STRATUS OUT. SATELLITE FOG LOOP SHOWS THE STRATUS NOT
MOVING OR CHANGING MUCH. AT THIS RATE...WILL HAVE TO KEEP SKIES CLOUDY
THROUGH MOST OF THE DAY. DO EXPECT SOME CLEARING TO START SHOWING
IN TOUR N THIS AFTERNOON. AS THE SURFACE HIGH MOVES NEAREST TO US
AND THEN SE...IT SHOULD CLEAR ALL STRATUS OUT THIS EVENING. WILL CONFINE
FLURRY MENTION TO OUR EXTREME SW WHERE THERE ARE LAYERED HIGHER
CLOUD STILL ABOVE THE STRATUS.
OVERCAST HELD LOWS UP 10F OR MORE THAN EXPECTED LAST NIGHT.
HOWEVER WITH THE STRATUS STICKING AROUND MOST OF THE DAY...AND
COLDER PART OF THE AIRMASS NOW OVER US...HIGHS WON`T BE VERY MUCH
WARMER THAN THIS MORNINGS LOWS. COLDER TONIGHT THOUGH WITH
CLEARING SKIES FINALLY.
REX BLOCK UPPER PATTERN HAS BEEN BREAKING DOWN. UPPER RIDGE WILL
SHIFT AROUND A LITTLE...BUILDING STRONGLY N OVER THE PACIFIC COAST
STATES AND BC. THIS WILL INCREASE THE NNW FLOW ALOFT OVER OUR AREA
BETWEEN HE RIDGE AND THE HUDSON BAY LOW.
THE CANADIAN HIGH PRESSURE MOVES SE OUT OF THE AREA WED...ALLOWING
FOR SOME WARMING UNDER SUNNY SKIES. MODELS HAVE BEEN TRENDING
SLOWER WITH THE NEXT COLD FRONT THAT ARRIVES IN THE NNW FLOW...NOW
MOVING THRU THE CWA THURSDAY. 850 MB WINDS INCREASE TO AS HIGH AS
40KT 12-15Z. MODEL FORECAST SOUNDINGS ARE JUST SHORT OF DRY
ADIABATIC MIXED TO AROUND 900 MB AT THAT TIME AS MODERATE COLD
ADVECTION STARTS IN OUR N. SO TIMING NOT QUITE IDEAL TO MIX
MAXIMUM WINDS TO SURFACE...BUT IT WILL BE WINDY. AS WE MIX DRY
ADIABATICALLY TO ABOVE 900 MB IN THE AFTERNOON...WINDS AT THAT
LEVEL ARE LESS THEN. ANOTHER DRY COLD FRONT. MODELS INDICATE THERE
WILL BE JUST A SHORTLIVED NARROW BAND OF STRATUS BEHIND THE FRONT. SIMONSEN
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED BEGINS WITH HIGH PRESSURE OVER MANITOBA AND A
STATIONARY FRONT UP AGAINST THE ROCKY MOUNTAIN FRONT RANGE. MODELS
IN FAIR AGREEMENT WITH THIS SOLUTION FOR THE START OF THE PERIOD
FRIDAY MORNING.
FRIDAY THROUGH THE WEEKEND THE UPPER LOW OVER HUDSON BAY MOVES
INTO QUEBEC DRAGGING THE HIGH PRESSURE SYSTEM OVER MANITOBA SOUTH
AND EAST TOWARDS THE GREAT LAKES. THE NEXT EFFECT WILL BE A
WARMING TREND FOR NORTHEAST MONTANA. THE STATIONARY FRONT WILL
BECOME MORE OF A LEE TROUGH AND COULD PROVIDE A FOCUS OVER THE FAR
WESTERN ZONES FOR SOME VERY LIGHT PRECIPITATION. WILL KEEP THE
MENTION OF PRECIPITATION OUT FOR THE ZONES AT THIS TIME.
EARLY NEXT WEEK...THE EC AND GFS BRING AN UPPER LEVEL LOW THROUGH
NORTHEAST MONTANA AT DIFFERENT TIME STEPS... FOR NOW WILL JUST
KEEP SLIGHT CHANCE POPS IN THE FORECAST UNTIL THE MODELS COME
TOGETHER WITH FUTURE RUNS. PROTON
&&
.AVIATION...
MVFR STRATUS IS HOLDING OVER THE REGION. DO EXPECT THE MVFR
CEILINGS TO CONTINUE OVER THE REGION THROUGH 18Z. THE CEILINGS
SHOULD SLOWLY BREAK UP AFTER THAT. FOLLOWING THE HRRR AND SREF
GUIDANCE THIS MORNING SINCE THE MOS PRODUCTS HAVE HANDLED THIS
EVENT POORLY. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BILLINGS MT
336 AM MST TUE FEB 7 2012
.SHORT TERM...VALID FOR TDY AND WED...
MOISTURE CHANNEL IMAGERY AT 10 UTC REVEALS SIGNIFICANT DRYING OVER
NORTHERN MT...WITH SOME OF THE MOST ROBUST DARKENING ACTUALLY NEAR
GREAT FALLS. RUC OBJECTIVE ANALYSES SUGGEST THAT A SIGNIFICANT 1.5
PVU LOWERING DOWN TO NEAR 500 HPA IS ASSOCIATED WITH THIS FEATURE.
THIS FORCING IS MUCH SLOWER AND FURTHER WEST THAN WHAT MODELS HAVE
BEEN SUGGESTING...PERHAPS THANKS TO THE DOWNSTREAM PATTERN THAT IS
LARGELY INFLUENCED BY THE REMNANT REX BLOCK OF LAST WEEKEND. THERE
IS THUS INCREASING CONCERN THAT AT LEAST SOME LIGHT SNOW SHOULD BE
MORE PREVALENT OVER SOUTH CENTRAL MT TODAY THAN EARLIER THOUGHT AS
THIS FEATURE WORKS IN CONCERT WITH UPSLOPE FLOW AND MODEST AMOUNTS
OF LOW- TO MID-LEVEL FRONTOGENESIS.
AS FAR AS THE DETAILS GO...THE SHALLOW UPSLOPE FLOW WHICH HAS BEEN
OCCURRING BENEATH THE DENDRITIC LAYER HAS BEEN RESPONSIBLE FOR 0.5
TO 1.0 INCH SNOW AMOUNTS SINCE MONDAY. RADAR IMAGERY SUGGESTED THE
SNOW TAPERED OFF TO FLURRIES BY 06 UTC...BUT MORE RECENTLY WE NOTE
SOME ADDITIONAL ENHANCEMENT SOUTH OF BILLINGS NEAR WHERE WE EXPECT
SOME FRONTOGENESIS OR WEAK WARM AIR ADVECTION TO BEGIN. THIS RADAR
TREND CONFIRMS THE IDEA HELD BY THE 03 AND 06 UTC RUC RUNS OF SOME
RENEWED SNOW FROM BIG TIMBER TO BILLINGS AND HARLOWTON TODAY. SNOW
IS SUPPORTED BY LIGHT UPSLOPE FLOW IN AND OF ITSELF...BUT IT LOOKS
LIKE THESE RUC RUNS ARE KEYING IN ON ENOUGH QPF FOR SOME 1-3 INCH
SNOW AMOUNTS THROUGH SIMULATION OF DEEPER FORCING WITH THE WAVE IN
CENTRAL MT AMIDST A MODEST LOW- AND MID-LEVEL FRONTOGENESIS ZONE.
THE 00 UTC NAM AND GFS ALSO SUGGEST NOTABLE VERTICAL MOTION ON 285
AND 290 K ISENTROPIC SURFACES IN THESE SAME AREAS TODAY...AND THEY
EVEN SHOW POSITIVE PRESSURE ADVECTION OF 1 TO 2 HPA. THE LATEST 06
UTC NAM RESPONDS TO THIS BY SHOWING QPF FROM BILLINGS WEST OVER TO
BIG TIMBER AND NORTH TO HARLOWTON AND ROUNDUP TODAY. ADDING TO THE
BELIEF THAT THERE WILL BE SOME LIGHT SNOW IN THESE AREAS TODAY ARE
THE 00 UTC GEFS MEMBERS...OF WHICH SEVERAL SHOW PRECIPITATION EVEN
AFTER 18 UTC TODAY. AS A RESULT...WE HAVE INCLUDED LIKELY AND EVEN
CATEGORICAL POPS TODAY FOR PARTS OF SOUTH CENTRAL MT. NOTE THAT WE
FEEL THE FOOTHILLS REQUIRE NO MORE THAN CHANCE POPS TODAY GIVEN AN
EXPECTATION FOR THE LOW- AND MID-LEVEL FRONT TO PULL NORTHEAST OFF
OF THEM DURING THE MORNING. RADAR TRENDS AT 10 UTC CONFIRM THIS.
THOUGH LIQUID PRECIPITATION AMOUNTS WILL BE LIGHT...SNOW RATIOS ON
THE ORDER OF 15 OR 20 TO 1 WILL YIELD ANOTHER 0.5 TO 1 INCH ACROSS
PARTS OF SOUTH CENTRAL MT. ADMITTEDLY...PLACES THAT END UP BENEATH
A PERSISTENT LIGHT SNOW BAND COULD PICK UP CLOSER TO 2 OR 3 INCHES
LIKE THE 03 UTC RUC SHOWED...BUT WHICH IT HAS SINCE BACKED OFF ON.
WHILE WE DO NOT FEEL AN ADVISORY WILL BE NECESSARY...IT IS NOT OUT
OF THE QUESTION THAT A SHORT-FUSE ONE COULD STILL BE REQUIRED ONCE
TRENDS BECOME ESTABLISHED WITH MORE CONFIDENCE THIS MORNING.
STRATUS REMAINS ENTRENCHED ALONG AND WEST OF THE SURFACE HIGH AXIS
ALL THE WAY NORTH INTO CENTRAL SASKATCHEWAN AS OF 10 UTC...SO WITH
PERSISTENT UPSLOPE EXPECTED TODAY...WE DECIDED TO KEEP SUBSTANTIAL
AMOUNTS OF CLOUDS IN THE FORECAST AREA-WIDE. OF COURSE...THE MODEL
GUIDANCE WOULD HAVE US BELIEVE OTHERWISE...BUT CASES LIKE THIS ONE
OFTEN BENEFIT FROM A PERSISTENCE FORECAST. WE ARE PORTRAYING HIGHS
IN THE 20S F TODAY...WHICH IS COLDER THAN EARLIER FORECASTS DUE TO
THE ADDITIONAL STRATUS AND WEAK BOUNDARY LAYER FLOW.
WARM AIR ADVECTION WILL GET GOING ON WED...BUT HOW QUICKLY THAT IS
GOING TO TRANSLATE TO SURFACE WARMING IS SOMEWHAT UNCERTAIN WITH A
LINGERING NORTHERLY FLOW ALOFT. WE THUS LET CONTINUITY RULE DURING
THIS PART OF THE FORECAST FOR NOW. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
WEST COAST RIDGE AMPLIFICATION CONTINUES IN THE LATEST MODEL RUNS
FOR THURSDAY INTO FRIDAY. THIS ALLOWS COLD AIR OVER NORTHERN
CANADA TO DROP SOUTHWARD INTO THE NORTHERN PLAINS. MODELS HAVE
BEEN STRUGGLING WITH HOW FAR WEST TO ALLOW THIS COLD AIR TO
PENETRATE...AND LATEST RUNS CONTINUE THIS TREND. CURRENT THINKING
IS THAT LOW PRESSURE TO THE WEST OF THE AREA UNDER DEVELOPING
RIDGE SHOULD BE ENOUGH TO ALLOW COLD AIR TO BACK UP INTO THE
FOOTHILLS FOR LATE THURSDAY AND INTO FRIDAY. KEPT FORECAST ON THE
COLD SIDE OF GUIDANCE FOR THIS TIME FRAME. LATEST MODEL RUNS ALSO
KEEP PERSISTENT CYCLONIC FLOW OVER THE NORTHERN PLAINS PREVENTING
COLD AIR FROM FULLY RETREATING DURING THE WEEKEND FROM EASTERN
ZONES THIS SETS UP A POTENTIAL BAROCLINIC ZONE THAT WOULD PRODUCE
ISOLATED TO SCATTERED SNOW SHOWERS FROM TIME TO TIME. AS A RESULT
INCREASED POPS FOR THE COLD AIR BUILDING IN THURSDAY AND FRIDAY
AND FOR THE BAROCLINIC ZONE GOING INTO THE WEEKEND. MOISTURE IS
LIMITED DURING THIS TIME FRAME SO ANY SNOW ACCUMULATIONS SHOULD BE
LIGHT. A PATTERN CHANGE CONTINUES TO BE ADVERTISED BEGINNING THE
END OF THE WEEKEND THAT WOULD OPEN THE AREA UP TO SYSTEMS COMING
OFF THE NORTH PACIFIC. THIS WOULD BRING SEASONAL TEMPERATURES AND
MORE MOISTURE TO THE AREA MONDAY INTO THE MIDDLE OF NEXT WEEK.
CURRENTLY HAVE CLIMO TYPE TEMPERATURES AND POPS IN THE FORECAST
FOR THIS TIME FRAME. CHAMBERS
&&
.AVIATION...
MVFR TO OCCASIONAL IFR CONDITIONS WILL CONTINUE THROUGH THE
MORNING HOURS AT ALL TAF LOCATIONS. AREAS OF LIFR CONDITIONS ARE
POSSIBLE NEAR EXPECTED HEAVIER SNOW BANDS ACROSS CENTRAL AND
WESTERN ZONES INCLUDING KBIL AND KLVM. CONDITIONS WILL IMPROVE
OVER EASTERN AREAS INCLUDING KMLS AND KBHK AFTER 19Z WITH CLEARING
EXPECTED LATE AFTERNOON. LOW STRATUS AND LIGHT SNOW WILL LIKELY
PERSIST INTO EARLY EVENING OVER WESTERN AND CENTRAL AREAS
INCLUDING KBIL AND KSHR...THOUGH CEILINGS WILL LIFT AND BREAKS IN
OVERCAST CAN BE EXPECTED TO INCREASE AS THE AFTERNOON PROGRESSES.
CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 028 015/041 020/042 024/035 023/041 023/042 023/041
7/J 21/U 10/U 22/J 22/J 21/B 12/J
LVM 027 008/041 020/042 028/041 029/042 024/042 024/040
4/J 11/U 21/U 22/W 21/B 11/B 12/J
HDN 030 013/041 017/041 020/036 018/040 022/043 022/041
5/J 11/U 10/U 22/J 22/J 21/B 12/J
MLS 027 013/038 016/037 016/032 017/037 021/040 023/039
1/E 00/U 10/U 01/U 12/J 21/B 12/W
4BQ 027 013/038 016/038 017/032 016/036 020/040 022/039
1/C 11/U 10/U 02/J 22/J 22/W 12/J
BHK 025 007/035 012/028 014/025 011/033 018/037 021/037
0/E 01/U 10/N 00/U 01/B 11/B 12/J
SHR 027 006/040 017/039 019/034 020/037 018/040 021/039
3/J 11/U 11/U 22/J 22/W 21/B 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
339 PM EST TUE FEB 7 2012
.SYNOPSIS...
COLDER OVERNIGHT LOWS TONIGHT BEHIND A COLD FRONT WITH JUST STRAY
FLURRIES AND LIGHT SNOW SHOWERS THIS EVENING. A WEST TO EAST
TRACKING SNOW STORM WILL REMAIN SOUTH OF THE STATE LINE
WEDNESDAY...THOUGH CLOUDS WILL THICKEN ACROSS SOUTHERN PORTIONS OF
WESTERN AND CENTRAL NEW YORK. TEMPERATURES WEDNESDAY WILL REACH
INTO THE LOW 30S FOR MANY AREAS...AND A FEW DEGREES WARMER
THURSDAY UNDER ADDITIONAL SUNSHINE.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AT 20Z A COLD FRONT CONTINUES TO WEAKEN AND SLOW AS IT PUSHES SOUTHWARD INTO
NORTHERN PENNSYLVANIA THIS AFTERNOON WITH A NORTHERLY FLOW BEHIND
THE FRONT. HIGH PRESSURE OVER THE NORTHERN PLAINS CONTINUES TO RIDGE
EASTWARD BEHIND THIS SFC COLD FRONT.
VISIBLE SATELLITE IMAGERY DISPLAYS MUCH OF THE EASTERN LAKE ONTARIO
REGION NOW MOSTLY SUNNY...WITH A CLOUDY LOW DECK OF CLOUDS SOUTH OF
LAKE ONTARIO.
RADAR DISPLAYS LIGHT SNOW ACROSS AREAS SOUTH OF LAKE ONTARIO AND
WILL CONTINUE WITH THE LOW CHC POPS FOR SNOW SOUTH OF LAKE
ONTARIO...TAPERING OFF TO FLURRIES SOUTH OF THE THRUWAY. WITH LACK
OF MOISTURE IN THE SNOW GROWTH ZONE...AND LIGHT WINDS EXPECT JUST
THE FINE GRAINY SNOW TO CONTINUE. ACTIVITY SHOULD CONTINUE TO
DIMINISH THROUGH THE OVERNIGHT TIME PERIOD AS LOW LEVEL MOISTURE
DIMINISHES.
SEVERAL CHALLENGES IN THE OVERNIGHT TIME PERIOD ACROSS THE EASTERN
GREAT LAKES REGION. FIRST CHALLENGE IS THE TIMING OF THE CLEARING
BEHIND THE COLD FRONT. BOTH THE 12Z GFS/NAM...09Z SREF AND THE
LATEST MESOSCALE RUC LINGER LOW LEVEL MOISTURE AROUND 2-3K FEET
SOUTH OF LAKE ONTARIO. THE FLOW UP THROUGH 5K FEET OVERNIGHT WILL
REMAIN LIGHT...LESS THAN 10 KNOTS...BUT IT WILL HAVE A NORTH TO
NORTHEASTERLY COMPONENT WHICH WILL LEAD TO SOME UPSLOPE ACROSS
INTERIOR WESTERN AND CENTRAL NEW YORK. WHILE THE CLEARING LINE IS
NEAR THE MOHAWK VALLEY AND THE SOUTHERN LAKE ONTARIO SHORELINE THIS
LATE AFTERNOON...EXPECT THIS CLEARING LINE TO SLOW THIS EVENING WITH
THE SETTING SUN AND LOW CLOUDS TO REMAIN SOUTH OF LAKE ONTARIO
WITHIN THE LOW LEVEL MOISTURE. EXPECT THE NORTHERN HALF OF WNY AND
CNY TO HAVE CLEARING THROUGH THE OVERNIGHT...THOUGH BY TIME THE
CLEARING OF LOW CLOUDS REACHES THE SOUTHERN TIER...MID AND HIGH
LEVEL CLOUDS WILL BE THICKENING. THE CHALLENGE IS WITH THE CLEARING
LINE VERY CLOSE...CLOUDS MAY DISSIPATE QUICKER THAN FORECASTED
ESPECIALLY JUST SOUTH OF LAKE ONTARIO...WITH THE CURRENT FORECAST
TOO PESSIMISTIC ON OVERNIGHT CLOUD COVER.
CHALLENGE TWO TONIGHT WILL BE OVERNIGHT TEMPERATURES. WITH THE LOW
CLOUDS LINGERING THROUGH MUCH OF THE NIGHT TOWARDS THE SOUTH...AND MID
AND HIGH LEVEL CLOUDS ARRIVING OVERNIGHT WILL HEDGE ABOVE MODEL
GUIDANCE TO THE SOUTH FOR OVERNIGHT LOWS WITH READINGS IN THE LOW TO
MID 20S.
THE CHALLENGE WILL BE TO THE NORTH...ESPECIALLY THE EASTERN LAKE
ONTARIO REGION WHERE THE SKIES WILL BE MAINLY CLEAR AND WINDS LIGHT
AS HIGH PRESSURE RIDGES INTO THE REGION. TEMPERATURES ARE EXPECTED
TO FALL INTO THE SINGLE DIGITS...TO BELOW ZERO ACROSS THE NORTH
COUNTRY OVERNIGHT. HOWEVER DO NOT EXPECT TEMPERATURES TO FALL MUCH BELOW
MODEL GUIDANCE AS AN UPPER LEVEL TROUGH...AND WAA AT 925 HPA THROUGH
THE NIGHT ARE NOT FAVORABLE FOR CLASSIC RADIATIONAL COOLING.
TEMPERATURES AT BETWEEN 925 HPA AND 850 HPA ONLY DROP TO AROUND -9
TO -12C...WHICH IS NORMAL FOR THIS TIME OF YEAR...AND INDICATIVE
THAT THIS AIRMASS BEHIND THE COLD FRONT IS NOT YOUR CLASSIC DEEP
COLD ARCTIC AIRMASS. HOWEVER WITH THE LIGHT WINDS AND STILL ICY SNOW
COVER TEMPERATURES MAY DROP COLDER THAN FORECASTED ACROSS THE
EASTERN LAKE ONTARIO REGION. ELSEWHERE WILL GO NEAR MODEL
GUIDANCE...THOUGH TIMING OF THE CLEARING MAY CHANGE THE OVERNIGHT
LOWS EITHER SIDE OF THE FORECAST.
TOMORROW AN UPPER LEVEL SHORT WAVE WITHIN A ZONAL FLOW WILL DRIVE A
STORM SYSTEM FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHERN MID
ATLANTIC. PRECIPITATION FROM THIS SYSTEM IS EXPECTED TO REMAIN JUST
SOUTH OF THE STATE LINE...THOUGH MID AND HIGH LEVEL CLOUDS WILL
CROSS THE REGION. THESE CLOUDS WILL CREATE A CLOUDY DAY NEAR THE
STATE LINE WEDNESDAY...THOUGH FARTHER NORTH WHERE MOISTURE WILL BE
LESS EXPECT SUNSHINE TO BE MORE PLENTIFUL WITH MOSTLY SUNNY SKIES
ACROSS THE NORTH COUNTRY. TEMPERATURES WEDNESDAY WILL CLIMB TO NEAR
SEASONAL AVERAGES WITH LOW TO MID 30S PLENTIFUL ACROSS THE REGION.
WINDS WILL BE LIGHT TO START THE DAY AND BECOME MORE SOUTH TO
SOUTHWESTERLY LATE...AND INCREASE IN SPEED SOME AS WARM AIR ALOFT
BEGINS TO PUSH INTO THE REGION.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
WEDNESDAY EVENING A MID LEVEL TROUGH WILL BE MOVING ACROSS THE MID
ATLANTIC STATES WITH AN ASSOCIATED VERY WEAK SURFACE WAVE
REFLECTION. LATEST 12Z MODEL GUIDANCE REMAINS CONSISTENT IN KEEPING
ANY LIGHT SNOW WITH THIS SYSTEM JUST SOUTH OF THE PA/NY BORDER
WEDNESDAY EVENING. MID LEVEL CLOUDS WILL QUICKLY DECREASE FROM
NORTHWEST TO SOUTHEAST DURING THE EVENING AS THIS WAVE PULLS OFF THE
EAST COAST...LEAVING MOST AREAS MAINLY CLEAR OVERNIGHT.
THE ONLY POTENTIAL CONCERN IS THE POSSIBILITY OF SOME LAKE
EFFECT/UPSLOPE CLOUDS DEVELOPING EAST OF THE LAKES
OVERNIGHT...SIMILAR TO SCENARIOS WE HAVE SEEN IN RECENT DAYS.
WESTERLY FLOW OF ABOUT -6C AIR AT 850MB MAY BE ENOUGH TO ALLOW SOME
LAKE STRATUS TO DEVELOP...ESPECIALLY WITH AN ADDED BOOST FROM
UPSLOPE FLOW ACROSS THE WESTERN SOUTHERN TIER AND TUG HILL REGIONS.
WILL CONTINUE WITH HIGHER CLOUD AMOUNTS IN THESE AREAS LATER
WEDNESDAY NIGHT INTO THURSDAY MORNING TO ACCOUNT FOR THIS POTENTIAL.
OTHERWISE ON THURSDAY EXPECT MOST AREAS TO SEE A DECENT AMOUNT OF
SUNSHINE WITH INCREASING SOUTHWEST FLOW BOOSTING 850MB TEMPS UP TO
AROUND -4C. WITH NO SNOW ON THE GROUND IN MOST AREAS AND AMPLE
MIXING AND SUNSHINE...THIS SHOULD ALLOW TEMPS TO CLIMB INTO THE MID
TO UPPER 30S IN MANY AREAS...WITH LOW 40S IN THE WARMER SPOTS OF THE
GENESEE VALLEY AND FINGER LAKES. A SOUTHWEST FLOW OFF LAKE ERIE WILL
PREVENT THE BUFFALO AREA AND MUCH OF THE NIAGARA FRONTIER FROM
REACHING 40. IT WILL BE QUITE BREEZY AS WELL WITH GUSTS IN THE 30-35
MPH RANGE.
MORE OF THE SAME THURSDAY NIGHT INTO FRIDAY MORNING WITH DEEP
SOUTHWESTERLY FLOW KEEPING TEMPS ABOVE AVERAGE WITH DRY AND MAINLY
CLEAR SKIES. THE BREEZE WILL STAY UP THURSDAY NIGHT...KEEPING LOW
TEMPS ABOVE SEASONAL AVERAGES.
LATE FRIDAY INTO FRIDAY NIGHT THE NEXT SYSTEM OF INTEREST
APPROACHES...AND FORECAST UNCERTAINTY ALSO INCREASES. IN A GENERAL
SENSE...A LONGWAVE TROUGH WILL BEGIN TO CARVE OUT ACROSS EASTERN
CANADA WITH THE FIRST LOBE OF LOWER HEIGHTS SWINGING DOWN THROUGH
THE GREAT LAKES FRIDAY NIGHT. THE 12Z GFS REMAINS CONSISTENT WITH
PREVIOUS RUNS AND HAS A CLEAN...SIMPLE ARCTIC FRONT PASSAGE FRIDAY
NIGHT WITH 850MB TEMPS DROPPING TO -22C TO -24C BY SATURDAY MORNING.
THE ECMWF AND CANADIAN GEM ALSO REMAIN CONSISTENT WITH THEIR
PREVIOUS RUNS AND DEVELOP A WEAK WAVE OF LOW PRESSURE ALONG THE
ARCTIC FRONT OVER THE LOWER LAKES. THIS WOULD DO TWO THINGS.
FIRST...THE WAVE WOULD BRING A GENERAL LIGHT SNOW TO THE ENTIRE
REGION. SECOND...IT WOULD ALSO SLOW THE ARRIVAL OF THE COLDEST AIR
UNTIL LATER IN THE DAY SATURDAY. THE ECMWF AND GEM ARE ALSO NOT AS
EXTREME WITH THE COLD AIR BEHIND...WITH 850MB TEMPS BOTTOMING OUT
-18C.
IN EITHER SCENARIO...THE ARCTIC FROPA OR WAVE OF LOW PRESSURE...
MOST AREAS SHOULD SEE AT LEAST SOME SNOWFALL FRIDAY NIGHT SO THIS
GIVES ENOUGH CONFIDENCE TO RAISE POPS TO LIKELY. THE MAIN FORECAST
CHALLENGE THEN IS HOW QUICKLY TO BRING IN THE COLD AIR. FOR NOW HAVE
GONE WITH A MIDDLE OF THE ROAD SOLUTION...BUT IF THE GFS VERIFIES
FRIDAY NIGHT LOWS WILL BE MUCH COLDER THAN CURRENTLY FORECAST...AND
IF THE ECMWF/GEM IDEA VERIFIES THEY WILL BE MILDER.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
MODEL UNCERTAINTY ABOUNDS NEXT WEEKEND WITH MEDIUM RANGE GUIDANCE
CONTINUING TO STRUGGLE WITH THE DETAILS OF A LONGWAVE TROUGH
AMPLIFICATION IN EASTERN CANADA AND NEW ENGLAND. THE LATEST 12Z
ECMWF HAS OFFERED ANOTHER EXTREME SOLUTION...DROPPING A MAJOR CHUNK
OF THE POLAR VORTEX INTO NORTHERN NEW ENGLAND ON MONDAY WITH 850MB
TEMPS BOTTOMING OUT AROUND -34C OVER THE ADIRONDACKS AND ABOUT -24C
ACROSS WESTERN NY. THE GFS IS LESS AMPLIFIED...KEEPING A FLATTER
TROUGH WHICH DIRECTS THE COLDEST AIR THROUGH NORTHERN NEW ENGLAND
SUNDAY AND MONDAY...WITH A STEADY MODERATING TREND ACROSS THE LOWER
LAKES.
THE ECMWF IS AN EXTREME SOLUTION FOR SURE...AND SUCH EXTREME
SOLUTIONS THIS FAR OUT RARELY VERIFY. THE ECMWF IS ALSO STRUGGLING
MORE THAN OTHER MODEL GUIDANCE WITH RUN TO RUN CONSISTENCY INVOLVING
THESE DETAILS. FOR NOW WILL JUST KEEP TEMPS A LITTLE COOLER THAN THE
GFS SOLUTION FOR SUNDAY AND MONDAY ESPECIALLY ACROSS THE NORTH
COUNTRY. HAVE ALSO MAINTAINED A CHANCE OF SNOW SHOWERS FOR MOST OF
THE WEEKEND WITH COLD NORTHWEST FLOW BECOMING MORE WESTERLY ON
SUNDAY. THERE WILL BE SOME LAKE EFFECT/ENHANCED SNOW...BUT WITH THE
BIG RUN TO RUN AND INTER-MODEL DIFFERENCES THERE IS NO WAY OF
KNOWING THE DETAILS OF WHEN AND WHERE...OR AMOUNTS YET.
IT DOES APPEAR THAT A MODERATING TREND WILL BEGIN NEXT WEEK ONCE
AGAIN...ALTHOUGH THE DEGREE OF WARMING IS QUITE DIFFERENT BETWEEN
THE ECMWF/GFS SOLUTIONS. THE 12Z GFS SHOWS A GENERAL LIGHT SNOWFALL
FOR DAY 7 TUESDAY...BUT THIS HAS LITTLE SUPPORT FROM THE ECMWF OR
MOST GEFS ENSEMBLE MEMBERS SO FOR NOW WILL KEEP TUESDAY DRY WITH
TEMPS MODERATING BACK TO A LITTLE ABOVE AVERAGE.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
FOR THE 21Z TAF UPDATE LOW MVFR AND PATCHY IFR FLIGHT CONDITIONS
WERE FOUND SOUTH OF LAKE ONTARIO WITH LIGHT NORTHERLY WINDS. LOW
LEVEL MOISTURE WILL MAINTAIN LOW CIGS THIS LATE AFTERNOON WITH
SCATTERED SNOW SHOWERS...ESPECIALLY NEAR THE KJHW AND KROC
TERMINALS.
AS MOISTURE BEGINS TO DIMINISH THIS EVENING THE SCATTERED FLURRIES
AND SNOW SHOWERS WILL COME TO AND END...THOUGH WITH THE LIGHT
UPSLOPE FLOW MVFR LEVEL CLOUDS WILL HANG TOUGH TILL THE OVERNIGHT
TIME PERIOD.
EXCEPTION TO THIS WILL BE THE NORTH COUNTRY WHERE SKIES WILL
CONTINUE TO REMAIN MAINLY CLEAR OVERNIGHT.
EXPECT A RETURN TO VFR FLIGHT CONDITIONS LATE OVERNIGHT...WITH VFR
CONDITIONS REMAINING THROUGH THE DAY WEDNESDAY...THOUGH AN OVC MID
LEVEL DECK OF CLOUDS WILL CROSS NEAR THE STATE LINE. WINDS THROUGH
THE FIRST HALF OF WEDNESDAY WILL REMAIN LIGHT...GENERALLY UNDER 10
KNOTS.
OUTLOOK...
WEDNESDAY AND THURSDAY...MAINLY VFR.
FRIDAY...AREAS OF MVFR/IFR IN SNOW SHOWERS LATE AND OVERNIGHT.
SATURDAY AND SUNDAY...AREAS MVFR IN SCATTERED SNOW SHOWERS.
&&
.MARINE...
HIGH PRESSURE RIDGING INTO THE REGION FROM THE NORTHERN PLAINS WILL
CREATE A QUIET PERIOD WITH RELATIVELY LIGHT WINDS TONIGHT AND
WEDNESDAY ACROSS THE EASTERN GREAT LAKES. WINDS WILL INCREASE
OVERNIGHT WEDNESDAY AND INTO THURSDAY AND FRIDAY WITH WAVES AND
WINDS LIKELY REACHING SMALL CRAFT CRITERIA ON THE LAKES BOTH
THURSDAY AND FRIDAY.
&&
.CLIMATE...
THE INCREDIBLE WARMTH AND LACK OF SNOW CONTINUES FOR ANOTHER WEEK
HERE IN WESTERN AND CENTRAL NY. AS WE GO DEEPER AND DEEPER INTO THE
WINTER SEASON...THE STATS FOR LACK OF SNOW AND TEMPERATURES ARE
BECOMING QUITE IMPRESSIVE.
FOR BOTH BUFFALO AND ROCHESTER STATS AND RANKINGS BELOW...THE ENTIRE
141 YEARS OF RECORD WERE USED UNLESS OTHERWISE NOTED.
FOR ROCHESTER...
SNOWFALL FOR THE SEASON THROUGH FEB 5TH STANDS AT 25.5 INCHES.
NORMAL TO DATE WOULD BE 61.5 INCHES. THIS RANKS AS THE 10TH LEAST ON
RECORD. THERE IS A CAVEAT TO THIS...TWO OF THE YEARS THAT RANK WITH
LESS SNOW FROM THE 1800S HAVE SOME MISSING DATA...SO THE RANKING MAY
EVEN BE A NOTCH OR TWO HIGHER. THE LEAST SNOWY SEASON ON RECORD
THROUGH FEB 5TH WAS 1932-33 WITH 11.0 INCHES.
NUMBER OF DAYS WITH SNOW ON THE GROUND IS A VERY TELLING METRIC ON
WINTER SEVERITY SINCE IT RELATES TO BOTH SNOWFALL AND TEMPERATURE.
THIS YEAR THERE HAVE BEEN 9 DAYS WITH AN INCH OR MORE OF SNOW ON THE
GROUND. THE NORMAL FOR THE ENTIRE SEASON IS 76 DAYS...AND THE RECORD
LOW NUMBER OF DAYS IS 35 SET BACK IN 1932-33. IF THE PATTERN
CONTINUES THROUGH THE REST OF WINTER AND EARLY SPRING...THE ALL TIME
RECORD MAY BE IN REACH. NOTE THAT SNOW DEPTH DATA IS NOT COMPLETE IN
THE EARLY YEARS OF RECORD...SO THE SNOW DEPTH DATA WAS ANALYZED
SINCE THE WINTER OF 1926-27.
TEMPERATURES HAVE ALSO BEEN VERY MILD MOST OF THE TIME FROM LATE
FALL THROUGH THE WINTER TO THIS POINT. THE AVERAGE TEMPERATURE FROM
NOVEMBER 1ST THROUGH FEBRUARY 5TH WAS 36.9 DEGREES...WHICH IS ABOUT
6 DEGREES ABOVE AVERAGE. THIS RANKS AS 4TH WARMEST ON RECORD FOR
THAT STRETCH. THE RECORD WARMEST DURING THAT PERIOD WAS 39.9 DEGREES
SET IN 1931-32.
FOR BUFFALO...
SNOWFALL FOR THE SEASON THROUGH FEB 5TH STANDS AT 24.6 INCHES.
NORMAL TO DATE WOULD BE 65.0 INCHES. THIS RANKS AS THE 12TH LEAST ON
RECORD. THE LEAST SNOWY SEASON ON RECORD THROUGH FEB 5TH WAS
1889-1890 WITH 11.9 INCHES. A MORE RECENT YEAR WITH VERY LOW SNOW
WAS 1988-1989 WITH 20.9 INCHES THROUGH FEB 5TH...WHICH RANKS AS 5TH
LEAST ON RECORD.
NUMBER OF DAYS WITH SNOW ON THE GROUND IS A VERY TELLING METRIC ON
WINTER SEVERITY SINCE IT RELATES TO BOTH SNOWFALL AND TEMPERATURE.
THIS YEAR THERE HAVE BEEN 15 DAYS WITH AN INCH OR MORE OF SNOW ON
THE GROUND. THE NORMAL FOR THE ENTIRE SEASON IS 72 DAYS...AND THE
RECORD LOW NUMBER IS 29 DAYS SET BACK IN 1918-19. IF THE PATTERN
CONTINUES THROUGH THE REST OF WINTER AND EARLY SPRING...THE ALL TIME
RECORD MAY BE IN REACH. NOTE THAT SNOW DEPTH DATA IS NOT COMPLETE IN
THE EARLY YEARS OF RECORD...SO THE SNOW DEPTH DATA WAS ANALYZED
SINCE THE WINTER OF 1893-94.
TEMPERATURES HAVE ALSO BEEN VERY MILD MOST OF THE TIME FROM LATE
FALL THROUGH WINTER TO THIS POINT. THE AVERAGE TEMPERATURE FROM
NOVEMBER 1ST THROUGH FEBRUARY 5TH IS 37.2 DEGREES...WHICH IS ABOUT 6
DEGREES ABOVE AVERAGE. THIS RANKS AS THE 2ND WARMEST ON RECORD FOR
THAT STRETCH. THE RECORD WARMEST DURING THAT PERIOD WAS 37.4 DEGREES
SET IN 2001-2002.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...THOMAS
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...THOMAS
MARINE...THOMAS
CLIMATE...HITCHCOCK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
328 AM CST TUE FEB 7 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY...
THE BIGGEST CHALLENGE FOR TODAY WILL BE THE EVOLUTION OF THE STRATUS
DECK ACROSS WESTERN NORTH DAKOTA. THE HRRR MODEL AS HAS BEEN THE
CASE OVER THE PAST FEW DAYS SEEMS TO HAVE TO THE BEST HANDLE ON THE
STRATUS...AND KEEPS IT IN PLACE WEST OF HIGHWAY 83 THROUGH THE
AFTERNOON WHICH SEEMS REASONABLE GIVEN THE LACK OF MIXING WITH
SURFACE HIGH PRESSURE IN PLACE. DO EXPECT A SLOW EROSION OF THE
EASTERN PERIPHERY OF THE STRATUS THROUGH THE AFTERNOON...AND FOR NOW
HAVE SKIES CLEARED ACROSS THE WEST BY 00 UTC. HOWEVER...UNCERTAINTY
IS HIGH...AND IT IS ENTIRELY POSSIBLE THAT AT LEAST A PORTION OF THE
DECK MAY SURVIVE PAST 00 UTC. THE STRATUS SHOULD HOLD HIGH
TEMPERATURES NEAR 20 ACROSS THE WEST...WITH MID 20S FOR HIGHS ACROSS
THE CENTRAL OUTSIDE OF THE STRATUS. ISOLATED FLURRIES THROUGH THE
DAY ARE POSSIBLE UNDER THE STRATUS DECK.
WITH CLEAR SKIES ACROSS THE CWA TONIGHT...ASSUMING ALL THE
STRATUS ERODES...AND LIGHT WINDS WITH SURFACE HIGH PRESSURE IN
PLACE...GOOD RADIATIONAL COOLING IS EXPECTED WITH LOWS MAINLY IN
THE SINGLE DIGITS ABOVE ZERO...WITH A FEW SUBZERO READINGS
POSSIBLE AT THE FAVORED COOLER LOCATIONS ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. WEDNESDAY LOOKS TO BE ANOTHER MILD FEBRUARY
DAY WITH SOUTHWEST RETURN FLOW ESTABLISHING ITSELF AS THE
AFOREMENTIONED HIGH PRESSURE SYSTEM PROPAGATES INTO THE CENTRAL
PLAINS. WITH THE LACK OF SNOW COVER...BIAS CORRECTED GUIDANCE
WHICH IS WARMER THAN THE DETERMINISTIC AND STATISTICAL GUIDANCE
SUITE IS FAVORED WHICH WOULD SUGGEST WIDESPREAD HIGHS IN THE UPPER
30S FOR WEDNESDAY WITH GREATER MIXING GIVEN THE BROWN GROUND.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY.
FORECAST PROBLEM IN THE LONG TERM PERIOD WILL BE TEMPERATURES.
LITTLE IF ANY SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE
WEEK...WITH ONLY A SMALL INCREASE IN PRECIPITATION CHANCES EARLY
NEXT WEEK.
MODELS ARE INDICATING THE BLOCKING PATTERN OVER THE CONTINENTAL U.S.
THE PAST SEVERAL DAYS WILL COME TO AN END. THE MAIN FORECAST PROBLEM
WILL BE EXACTLY HOW AND WHEN THIS TAKES PLACE. THE REX BLOCK OVER
THE WESTERN U.S. WILL CONTINUE TO WEAKEN/DIMINISH EARLY IN THE
FORECAST PERIOD...ALLOWING THE POLAR VORTEX TO BRING ANOTHER SHOT OF
COLDER AIR TO THE REGION LATER THIS WORK WEEK. THEN AS RIDGING TO
OUR WEST BREAKS DOWN AMID STRONG ZONAL FLOW FROM THE PACIFIC THE
POLAR VORTEX WILL LIFT WELL NORTHEAST AS QUASI-ZONAL PROGRESSIVE
FLOW DEVELOPS BY EARLY NEXT WEEK. WILL UTILIZE A GENERAL BLEND AS
MODELS ARE SHOWING ABOVE NORMAL AGREEMENT EARLY IN THE LONG TERM
PERIOD. LATER ON AS WE FIRST SEE ANOTHER SHOT OF COLD AIR BEFORE THE
VORTEX GETS DISLODGED...MODEL SPREAD INCREASES SIGNIFICANTLY AND A
CONTINUATION OF THE CONSENSUS BLEND SEEMS REASONABLE.
AS FAR AS THE DETAILS...NORMAL TO ABOVE NORMAL TEMPERATURES
WEDNESDAY NIGHT...THEN COLD AIR ARRIVES ON THURSDAY WITH HIGHS
MAINLY IN THE TEENS FAR NORTH...BUT STILL HOLDING INTO THE LOWER
30S SOUTH. SOME SUB-ZERO LOWS POSSIBLE NORTH CENTRAL THURSDAY
NIGHT...WITH COLD TEMPERATURES REMAINING OVER THE NORTHEAST HALF OF
THE CWA FRIDAY...WHILE SEASONABLE HIGHS REMAIN OVER THE SOUTHWEST.
THEN A SLOW MODERATION IN TEMPERATURES IS IN STORE OVER THE WEEKEND
AND INTO EARLY NEXT WEEK.
AS WE ENTER A MORE PROGRESSIVE QUASI-ZONAL FLOW...WE WILL SEE AN
INCREASE IN DISTURBANCES TRAVERSING THE AREA EARLY NEXT WEEK. AT
THIS TIME...NOTHING LOOKS TO BE SIGNIFICANT WEATHER MAKER.
&&
.AVIATION...
HIGH PRESSURE OVER SOUTHERN SASKATCHEWAN AND MANITOBA
WILL DROP SOUTH ACROSS THE AREA TODAY. THIS WILL BRING VFR
CONDITIONS TO THE AREA. THE EASTERN TAF SITES OF MINOT AND JAMESTOWN
WILL LIKELY SEE VFR CONDITIONS THROUGH THE PERIOD...WHILE WILLISTON
AND DICKINSON WILL SEE MVFR-IFR CLOUDS LINGER THROUGH AT LEAST MID
MORNING BEFORE DISSIPATING. IN ADDITION...MODELS MAY BE CLEARING OUT
THE WEST TOO QUICKLY AND WILL KEEP LOWER STRATUS IN THE WEST LONGER
THAN MODELS INDICATE. ONCE THE STRATUS DOES DISSIPATE...VERY DRY AIR
ALOFT WILL KEEP VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PJA
LONG TERM/AVIATION....TWH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
127 PM EST TUE FEB 7 2012
.SYNOPSIS...
HIGH PRESSURE THIS AFTERNOON. A COLD FRONT PASSES WITH AN UPPER
DISTURBANCE TO PROVIDE A COLD RAIN OR SNOW TUESDAY NIGHT AND
WEDNESDAY. ARCTIC AIR WITH SNOW SHOWERS ARRIVES THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED...
NO CHANGES NEEDED FOR 15Z UPDATE. STRATUS DECK OVER SOUTHEAST OHIO
WILL BE VERY SLOW TO ENCROACH INTO WEST VIRGINIA.
PREVIOUS DISCUSSION BELOW...
WILL BE WATCHING LOW STRATUS DECK MOVING SE INTO OH EARLY THIS
MORNING. THIS SEEMS BE MARKED BY A WIND SHIFT TO MORE NW IN LWR
LVLS. HI RES LCL MDLS MDLS SEEM TO HAVE A MUCH BETTER HANDLE ON
THIS AS NAM AND GLOBAL MDLS ARE TOO SLOW AND NW WITH THIS. WILL
USE RUC AND WRF MDLS FOR TIMING...POISED TO MOVE INTO
PERRY...MORGAN...VINTON CO 10-12Z BEFORE PUTTING ON THE BRAKES IN
ITS SE ADVANCEMENT. OTHERWISE RVR VALLEY FG CENTRAL AND SOUTHERN
WV/SW VA WILL QUICKLY LIFT BY MID MORNING.
AFOREMENTIONED STRATUS DECK WILL VERY SLOWLY EDGE S AND E THRU THE
DAY...MORE E AND THAN S. HAVE INCREASING CLDS ACROSS NORTHERN WV
LOWLANDS AFTER 18Z. LOOKING AT YET ANOTHER SHARP CLD BOUNDARY
TDY...WITH A MAINLY SUNNY SKY SOUTH OF A KUNI...K3I2...KW22 LINE. AS
A RESULT TRIED TO SHOW MORE OF A TEMP GRADIENT WITH 50-52F SOUTH OF
LINE WITH MID 40S NORTH.
ATTENTION TURNS TO FAST MOVING S/W TROF POISED TO CROSS WED MORNING.
THERE DOES EXIST SOME TIMING DIFF AMONGST THE MODELS WITH GFS ON THE
FAST SIDE. TRIED TO GO TOWARD THE SLOWER SOLUTIONS. USING ISENTROPIC
LIFT FIELDS COMBINED WITH OMEGA IN H85-H7 LYR FOR POPS. THIS KEEPS
CWA DRY THRU 09Z...AMID INCREASING MID/HI CLDS. AFTER WHICH...
QUICKLY RAMP UP POPS FROM W TO E...HAVING HIGH END LKLY TO NEAR A
PKB-CRW-BKW-GRUN LINE AT 12Z. THIS MAY BE A LITTLE FAST AS 06Z NAM
CONT TO SLOW THINGS DOWN A BIT.
AS FOR PRECIP TYPE...MARGINAL WOULD BE AN UNDERSTATEMENT ACROSS
CENTRAL AND SOUTHERN AREAS. EVEN USING THE NAM PROFILES...YIELDS
TEMP CONUNDRUMS BLO H925. COMPOUNDING THE SITUATION IS EXTENT OF
RADIATIONAL COOLING TONIGHT BEFORE MID/HI CLDS PUT A LID ON THINGS.
TRIED TO SHOW A DROP IN TEMPS EARLY THIS EVE BEFORE STABILIZING AND
PERHAPS RISING A DEGREE BEFORE PCPN MOVES IN ACROSS WESTERN HALF OF
CWA. ALSO OF NOTE IS A WARM NOSE H95 TO H9 ALBEIT IN A DRY LYR.
THINKING A BRIEF ONSET OF RA OR A RA/SN MIX ALONG AND S OF I64
CORRIDOR BEFORE WET BULBING IN WARM NOSE COLLAPSES COLUMN AND TRIES
TO SWITCH PCPN OVER TO SN WITH A DEGREE OR TWO DROP IN SFC TEMPS TO
32-34F. HAVE ALLOWED SUCH A TRANSITION ACROSS WESTERN SE OH...NE
KY...WESTERN WV LOWLANDS...AND SW VA BY 12Z. AREAS FURTHER N FROM
ATH-PKB SHOULD START AS SN...WITH NORTHEASTERN QUADRANT STILL DRY AT
12Z. WILL ALLOW FOR A COATING ACROSS NE KY AND PARTS OF SE OH BY
12Z. VERY MUCH A LOW CONFIDENCE FCST AT THIS JUNCTURE WITH CRITICAL
TEMP THRESHOLDS SETTING UP AT THE SFC. COULD VERY WELL END UP BEING
MORE OF A MIX OR RA ON THE VALLEY FLOORS...INCLUDING CRW AND
HTS...WITH WET SNOW ON THE SURROUNDING HILLS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
PRECIPITATION TYPE ON WEDNESDAY IS RATHER TRICKY. BOUNDARY LAYER
COOLING TUESDAY EVENING IS CRITICAL TO THIS FORECAST. NAM SOLUTION
LOOKS FAIRLY REASONABLE...SO WILL STAY CLOSE TO IT...INCLUDING MET
MOS FOR HIGHS WEDNESDAY. THIS WOULD MEAN THAT THE LOW LANDS COULD
BOUNCE BETWEEN RAIN AND SNOW...WHILE THE HIGHER ELEVATIONS OF THE
MOUNTAINS WOULD BE ALL SNOW. ALSO INCREASED POPS TO LIKELY...AS BOTH
NAM AND GFS SHOWING GOOD MOISTURE AND LIFT.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT...FOLLOWED BY UPSLOPE
CONDITIONS. INCREASE POPS FOR FRIDAY NIGHT THROUGH SATURDAY
NIGHT...AND LOWERED HIGHS ON SATURDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
OPERATIONAL MODELS ADVERTISING A CLIPPER SYSTEM TO COME THROUGH THE
FIRST PART OF THE WEEKEND. QPF AMOUNTS WILL GENERALLY BE ON THE
LIGHT SIDE...WITH SOME SNOW EXPECTED...BUT SYSTEM WILL BE A QUICK
MOVER. COULD LEAVE SOME LINGERING UPSLOPE ON THE BACK SIDE THROUGH
THE DAY SATURDAY AND EARLY INTO SATURDAY NIGHT. THIS SYSTEM WILL
ALSO SERVE TO USHER IN A MORE WINTER LIKE AIRMASS AS 925MB
TEMPERATURES DROP TO AROUND 10C BELOW ZERO. WILL EXPECT A CLEAR
NIGHT SATURDAY NIGHT...AND WILL SEE MOST LOCATIONS DROPPING INTO THE
TEENS WHILE MOUNTAIN VALLEYS ARE IN THE HUNT FOR SINGLE DIGITS. HIGH
PRESSURE SETTLES IN FOR THE REMAINDER OF THE LONG TERM WITH
TEMPERATURES SLOW TO REBOUND THROUGH THIS PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
18Z TUESDAY THRU 18Z WEDNESDAY...
THRU 00Z...
WILL SEE LITTLE SOUTHEASTWARD PROGRESS OF MVFR STRATUS CURRENTLY
OVER SERN OHIO...UNTIL AFTER 20Z WHEN SOME MVFR CIGS MAY SNEAK INTO
NRN WV. OTHERWISE...VFR MOSTLY CLEAR.
AFTER 00Z...MVFR STRATUS HOLDING OVER SOUTHEASTERN OHIO...WHILE MID
CLOUDS STREAM EASTWARD FROM APPROACHING LOW PRESSURE AFTER 03Z.
AFTER 10Z...MVFR BECOMING IFR IN RAIN AND SNOW SPREADING RAPIDLY
EASTWARD...REACHING THE OHIO RIVER BY 14Z...AND OVER MOST OF THE ARE
BY 18Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF LOW STRATUS OVER SE OH
COULD VARY THRU 00Z.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H L L L M M M M M
CKB CONSISTENCY H H H H H H L M M H H H
AFTER 18Z WEDNESDAY...
IFR POSSIBLE DUE TO SNOW SHOWERS WEDNESDAY. IFR POSSIBLE IN SNOW
SHOWERS FRIDAY NIGHT THROUGH SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...26/RPY/30
NEAR TERM...JMV
SHORT TERM...RPY
LONG TERM...26
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1032 AM EST TUE FEB 7 2012
.SYNOPSIS...
HIGH PRESSURE THIS AFTERNOON. A COLD FRONT PASSES WITH AN UPPER
DISTURBANCE TO PROVIDE A COLD RAIN OR SNOW TUESDAY NIGHT AND
WEDNESDAY. ARCTIC AIR WITH SNOW SHOWERS ARRIVES THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED...
NO CHANGES NEEDED FOR 15Z UPDATE. STRATUS DECK OVER SOUTHEAST OHIO
WILL BE VERY SLOW TO ENCROACH INTO WEST VIRGINIA.
PREVIOUS DISCUSSION BELOW...
WILL BE WATCHING LOW STRATUS DECK MOVING SE INTO OH EARLY THIS
MORNING. THIS SEEMS BE MARKED BY A WIND SHIFT TO MORE NW IN LWR
LVLS. HI RES LCL MDLS MDLS SEEM TO HAVE A MUCH BETTER HANDLE ON
THIS AS NAM AND GLOBAL MDLS ARE TOO SLOW AND NW WITH THIS. WILL
USE RUC AND WRF MDLS FOR TIMING...POISED TO MOVE INTO
PERRY...MORGAN...VINTON CO 10-12Z BEFORE PUTTING ON THE BRAKES IN
ITS SE ADVANCEMENT. OTHERWISE RVR VALLEY FG CENTRAL AND SOUTHERN
WV/SW VA WILL QUICKLY LIFT BY MID MORNING.
AFOREMENTIONED STRATUS DECK WILL VERY SLOWLY EDGE S AND E THRU THE
DAY...MORE E AND THAN S. HAVE INCREASING CLDS ACROSS NORTHERN WV
LOWLANDS AFTER 18Z. LOOKING AT YET ANOTHER SHARP CLD BOUNDARY
TDY...WITH A MAINLY SUNNY SKY SOUTH OF A KUNI...K3I2...KW22 LINE. AS
A RESULT TRIED TO SHOW MORE OF A TEMP GRADIENT WITH 50-52F SOUTH OF
LINE WITH MID 40S NORTH.
ATTENTION TURNS TO FAST MOVING S/W TROF POISED TO CROSS WED MORNING.
THERE DOES EXIST SOME TIMING DIFF AMONGST THE MODELS WITH GFS ON THE
FAST SIDE. TRIED TO GO TOWARD THE SLOWER SOLUTIONS. USING ISENTROPIC
LIFT FIELDS COMBINED WITH OMEGA IN H85-H7 LYR FOR POPS. THIS KEEPS
CWA DRY THRU 09Z...AMID INCREASING MID/HI CLDS. AFTER WHICH...
QUICKLY RAMP UP POPS FROM W TO E...HAVING HIGH END LKLY TO NEAR A
PKB-CRW-BKW-GRUN LINE AT 12Z. THIS MAY BE A LITTLE FAST AS 06Z NAM
CONT TO SLOW THINGS DOWN A BIT.
AS FOR PRECIP TYPE...MARGINAL WOULD BE AN UNDERSTATEMENT ACROSS
CENTRAL AND SOUTHERN AREAS. EVEN USING THE NAM PROFILES...YIELDS
TEMP CONUNDRUMS BLO H925. COMPOUNDING THE SITUATION IS EXTENT OF
RADIATIONAL COOLING TONIGHT BEFORE MID/HI CLDS PUT A LID ON THINGS.
TRIED TO SHOW A DROP IN TEMPS EARLY THIS EVE BEFORE STABILIZING AND
PERHAPS RISING A DEGREE BEFORE PCPN MOVES IN ACROSS WESTERN HALF OF
CWA. ALSO OF NOTE IS A WARM NOSE H95 TO H9 ALBEIT IN A DRY LYR.
THINKING A BRIEF ONSET OF RA OR A RA/SN MIX ALONG AND S OF I64
CORRIDOR BEFORE WET BULBING IN WARM NOSE COLLAPSES COLUMN AND TRIES
TO SWITCH PCPN OVER TO SN WITH A DEGREE OR TWO DROP IN SFC TEMPS TO
32-34F. HAVE ALLOWED SUCH A TRANSITION ACROSS WESTERN SE OH...NE
KY...WESTERN WV LOWLANDS...AND SW VA BY 12Z. AREAS FURTHER N FROM
ATH-PKB SHOULD START AS SN...WITH NORTHEASTERN QUADRANT STILL DRY AT
12Z. WILL ALLOW FOR A COATING ACROSS NE KY AND PARTS OF SE OH BY
12Z. VERY MUCH A LOW CONFIDENCE FCST AT THIS JUNCTURE WITH CRITICAL
TEMP THRESHOLDS SETTING UP AT THE SFC. COULD VERY WELL END UP BEING
MORE OF A MIX OR RA ON THE VALLEY FLOORS...INCLUDING CRW AND
HTS...WITH WET SNOW ON THE SURROUNDING HILLS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
PRECIPITATION TYPE ON WEDNESDAY IS RATHER TRICKY. BOUNDARY LAYER
COOLING TUESDAY EVENING IS CRITICAL TO THIS FORECAST. NAM SOLUTION
LOOKS FAIRLY REASONABLE...SO WILL STAY CLOSE TO IT...INCLUDING MET
MOS FOR HIGHS WEDNESDAY. THIS WOULD MEAN THAT THE LOW LANDS COULD
BOUNCE BETWEEN RAIN AND SNOW...WHILE THE HIGHER ELEVATIONS OF THE
MOUNTAINS WOULD BE ALL SNOW. ALSO INCREASED POPS TO LIKELY...AS BOTH
NAM AND GFS SHOWING GOOD MOISTURE AND LIFT.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT...FOLLOWED BY UPSLOPE
CONDITIONS. INCREASE POPS FOR FRIDAY NIGHT THROUGH SATURDAY
NIGHT...AND LOWERED HIGHS ON SATURDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
OPERATIONAL MODELS ADVERTISING A CLIPPER SYSTEM TO COME THROUGH THE
FIRST PART OF THE WEEKEND. QPF AMOUNTS WILL GENERALLY BE ON THE
LIGHT SIDE...WITH SOME SNOW EXPECTED...BUT SYSTEM WILL BE A QUICK
MOVER. COULD LEAVE SOME LINGERING UPSLOPE ON THE BACK SIDE THROUGH
THE DAY SATURDAY AND EARLY INTO SATURDAY NIGHT. THIS SYSTEM WILL
ALSO SERVE TO USHER IN A MORE WINTER LIKE AIRMASS AS 925MB
TEMPERATURES DROP TO AROUND 10C BELOW ZERO. WILL EXPECT A CLEAR
NIGHT SATURDAY NIGHT...AND WILL SEE MOST LOCATIONS DROPPING INTO THE
TEENS WHILE MOUNTAIN VALLEYS ARE IN THE HUNT FOR SINGLE DIGITS. HIGH
PRESSURE SETTLES IN FOR THE REMAINDER OF THE LONG TERM WITH
TEMPERATURES SLOW TO REBOUND THROUGH THIS PERIOD.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
15Z TUESDAY THRU 12Z WEDNESDAY...
THRU 00Z...
WILL SEE LITTLE PROGRESS IN S AND E ADVANCEMENT OF STRATUS ACROSS SE
OH...UNTIL AFTER 18Z WHEN SOME MVFR CIGS MAY SNEAK INTO KPKB. THIS
STRATUS DECK WILL LIFT SOME WITH AFTN HEATING. OTHERWISE...VFR
MOSTLY CLEAR.
SOME MID/HI CLDS STREAMING IN AFTER 00Z...WELL AHEAD OF S/W TROF.
MVFR/IFR IN RA/SN MIX POSSIBLE BY 12Z ACROSS NE KY...WESTERN
LOWLANDS AND PORTIONS OF SE OH. CONFIDENCE NOT HIGH TO INCLUDE IN
TAFS THIS FAR OUT WITH MDLS TENDING TO SLOW THIS DOWN WITH EACH
RUN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF LOW STRATUS OVER SE OH
COULD VARY THRU 00Z. TIMING OF PCPN TOWARD END OF TAF PERIOD
ACROSS WEST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H M M M M H
CKB CONSISTENCY H H H H H H H H H H M M
AFTER 18Z WEDNESDAY...
IFR POSSIBLE DUE TO SNOW SHOWERS WEDNESDAY. IFR POSSIBLE IN SNOW
SHOWERS FRIDAY NIGHT THROUGH SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...26/RPY/30
NEAR TERM...JMV
SHORT TERM...RPY
LONG TERM...26
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
545 AM EST TUE FEB 7 2012
.SYNOPSIS...
HIGH PRESSURE TUESDAY. A COLD FRONT PASSES WITH AN UPPER DISTURBANCE
TO PROVIDE A COLD RAIN OR SNOW TUESDAY NIGHT AND WEDNESDAY. ARCTIC
AIR WITH SNOW SHOWERS ARRIVES THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED...
NO CHANGES NEEDED FOR 11Z UPDATE. STRATUS DECK ENCROACHING PERRY
CO RIGHT ON TIME.
PREVIOUS DISCUSSION BELOW...
WILL BE WATCHING LOW STRATUS DECK MOVING SE INTO OH EARLY THIS
MORNING. THIS SEEMS BE MARKED BY A WIND SHIFT TO MORE NW IN LWR
LVLS. HI RES LCL MDLS MDLS SEEM TO HAVE A MUCH BETTER HANDLE ON
THIS AS NAM AND GLOBAL MDLS ARE TOO SLOW AND NW WITH THIS. WILL
USE RUC AND WRF MDLS FOR TIMING...POISED TO MOVE INTO
PERRY...MORGAN...VINTON CO 10-12Z BEFORE PUTTING ON THE BRAKES IN
ITS SE ADVANCEMENT. OTHERWISE RVR VALLEY FG CENTRAL AND SOUTHERN
WV/SW VA WILL QUICKLY LIFT BY MID MORNING.
AFOREMENTIONED STRATUS DECK WILL VERY SLOWLY EDGE S AND E THRU THE
DAY...MORE E AND THAN S. HAVE INCREASING CLDS ACROSS NORTHERN WV
LOWLANDS AFTER 18Z. LOOKING AT YET ANOTHER SHARP CLD BOUNDARY
TDY...WITH A MAINLY SUNNY SKY SOUTH OF A KUNI...K3I2...KW22 LINE. AS
A RESULT TRIED TO SHOW MORE OF A TEMP GRADIENT WITH 50-52F SOUTH OF
LINE WITH MID 40S NORTH.
ATTENTION TURNS TO FAST MOVING S/W TROF POISED TO CROSS WED MORNING.
THERE DOES EXIST SOME TIMING DIFF AMONGST THE MODELS WITH GFS ON THE
FAST SIDE. TRIED TO GO TOWARD THE SLOWER SOLUTIONS. USING ISENTROPIC
LIFT FIELDS COMBINED WITH OMEGA IN H85-H7 LYR FOR POPS. THIS KEEPS
CWA DRY THRU 09Z...AMID INCREASING MID/HI CLDS. AFTER WHICH...
QUICKLY RAMP UP POPS FROM W TO E...HAVING HIGH END LKLY TO NEAR A
PKB-CRW-BKW-GRUN LINE AT 12Z. THIS MAY BE A LITTLE FAST AS 06Z NAM
CONT TO SLOW THINGS DOWN A BIT.
AS FOR PRECIP TYPE...MARGINAL WOULD BE AN UNDERSTATEMENT ACROSS
CENTRAL AND SOUTHERN AREAS. EVEN USING THE NAM PROFILES...YIELDS
TEMP CONUNDRUMS BLO H925. COMPOUNDING THE SITUATION IS EXTENT OF
RADIATIONAL COOLING TONIGHT BEFORE MID/HI CLDS PUT A LID ON THINGS.
TRIED TO SHOW A DROP IN TEMPS EARLY THIS EVE BEFORE STABILIZING AND
PERHAPS RISING A DEGREE BEFORE PCPN MOVES IN ACROSS WESTERN HALF OF
CWA. ALSO OF NOTE IS A WARM NOSE H95 TO H9 ALBEIT IN A DRY LYR.
THINKING A BRIEF ONSET OF RA OR A RA/SN MIX ALONG AND S OF I64
CORRIDOR BEFORE WET BULBING IN WARM NOSE COLLAPSES COLUMN AND TRIES
TO SWITCH PCPN OVER TO SN WITH A DEGREE OR TWO DROP IN SFC TEMPS TO
32-34F. HAVE ALLOWED SUCH A TRANSITION ACROSS WESTERN SE OH...NE
KY...WESTERN WV LOWLANDS...AND SW VA BY 12Z. AREAS FURTHER N FROM
ATH-PKB SHOULD START AS SN...WITH NORTHEASTERN QUADRANT STILL DRY AT
12Z. WILL ALLOW FOR A COATING ACROSS NE KY AND PARTS OF SE OH BY
12Z. VERY MUCH A LOW CONFIDENCE FCST AT THIS JUNCTURE WITH CRITICAL
TEMP THRESHOLDS SETTING UP AT THE SFC. COULD VERY WELL END UP BEING
MORE OF A MIX OR RA ON THE VALLEY FLOORS...INCLUDING CRW AND
HTS...WITH WET SNOW ON THE SURROUNDING HILLS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
PRECIPITATION TYPE ON WEDNESDAY IS RATHER TRICKY. BOUNDARY LAYER
COOLING TUESDAY EVENING IS CRITICAL TO THIS FORECAST. NAM SOLUTION
LOOKS FAIRLY REASONABLE...SO WILL STAY CLOSE TO IT...INCLUDING MET
MOS FOR HIGHS WEDNESDAY. THIS WOULD MEAN THAT THE LOW LANDS COULD
BOUNCE BETWEEN RAIN AND SNOW...WHILE THE HIGHER ELEVATIONS OF THE
MOUNTAINS WOULD BE ALL SNOW. ALSO INCREASED POPS TO LIKELY...AS BOTH
NAM AND GFS SHOWING GOOD MOISTURE AND LIFT.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT...FOLLOWED BY UPSLOPE
CONDITIONS. INCREASE POPS FOR FRIDAY NIGHT THROUGH SATURDAY
NIGHT...AND LOWERED HIGHS ON SATURDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
OPERATIONAL MODELS ADVERTISING A CLIPPER SYSTEM TO COME THROUGH THE
FIRST PART OF THE WEEKEND. QPF AMOUNTS WILL GENERALLY BE ON THE
LIGHT SIDE...WITH SOME SNOW EXPECTED...BUT SYSTEM WILL BE A QUICK
MOVER. COULD LEAVE SOME LINGERING UPSLOPE ON THE BACK SIDE THROUGH
THE DAY SATURDAY AND EARLY INTO SATURDAY NIGHT. THIS SYSTEM WILL
ALSO SERVE TO USHER IN A MORE WINTER LIKE AIRMASS AS 925MB
TEMPERATURES DROP TO AROUND 10C BELOW ZERO. WILL EXPECT A CLEAR
NIGHT SATURDAY NIGHT...AND WILL SEE MOST LOCATIONS DROPPING INTO THE
TEENS WHILE MOUNTAIN VALLEYS ARE IN THE HUNT FOR SINGLE DIGITS. HIGH
PRESSURE SETTLES IN FOR THE REMAINDER OF THE LONG TERM WITH
TEMPERATURES SLOW TO REBOUND THROUGH THIS PERIOD.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
ANY FOG ACROSS CENTRAL/SOUTHERN WV AND SW VA WILL QUICKLY LIFT
AND SCT OUT FOR VFR THRU AFTN.
ELSEWHERE...WILL SEE LITTLE PROGRESS IN S AND E ADVANCEMENT OF
STRATUS ACROSS SE OH...UNTIL AFTER 18Z WHEN SOME MVFR CIGS MAY
SNEAK INTO KPKB. THIS STRATUS DECK WILL LIFT SOME WITH AFTN
HEATING.
SOME MID/HI CLDS STREAMING IN AFTER 03Z...WELL AHEAD OF S/W TROF.
MVF/IFR IN RA/SN MIX POSSIBLE BY 12Z ACROSS NE KY...WESTERN
LOWLANDS AND PORTIONS OF SE OH. CONFIDENCE NOT HIGH TO INCLUDE IN
TAFS THIS FAR OUT WITH MDLS TENDING TO SLOW THIS DOWN WITH EACH
RUN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF LOW STRATUS OVER SE OH
COULD VARY THRU 18Z. TIMING OF PCPN TOWARD END OF TAF PERIOD
ACROSS WEST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY L L M H H H H H H H H H
HTS CONSISTENCY M M M H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H M H
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 12Z WEDNESDAY...
IFR POSSIBLE DUE TO SNOW SHOWERS WEDNESDAY. IFR POSSIBLE IN SNOW
SHOWERS FRIDAY NIGHT THROUGH SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...26/RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...26
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
112 AM EST TUE FEB 7 2012
.SYNOPSIS...
HIGH PRESSURE TUESDAY. A COLD FRONT PASSES WITH AN UPPER
DISTURBANCE TO PROVIDE WINTER PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATED...
AREAS OF LOW STRATUS LINGERING ACROSS THE NORTHERN MTNS AS OF 06Z.
THESE SHOULD DISSIPATE BY 09Z OR SO AS DRIER AIR WORKS IN THRU THE
COLUMN. OTHERWISE WILL BE WATCHING LOW STRATUS DECK MOVING SE INTO
OH. THIS SEEMS BE MARKED BY A WIND SHIFT TO MORE NW IN LWR LVLS. HI
RES LCL MDLS MDLS SEEM TO HAVE A MUCH BETTER HANDLE ON THIS AS NAM
AND GLOBAL MDLS ARE TOO SLOW AND NW WITH THIS. WILL USE RUC AND
WRF MDLS FOR TIMING WITH IT POISED TO MOVE INTO
PERRY...MORGAN...VINTON CO 10-12Z BEFORE PUTTING ON THE BRAKES IN
ITS SE ADVANCEMENT.
LAMP GUIDANCE IS INSISTING ON ADVECTING LWR DWPTS ACROSS THE NORTH
THRU MORNING WITH BL WINDS SLOWLY RELAXING. WILL KEEP MOST OF THE
FG IN RVR VALLEYS CENTRAL AND SOUTHERN WV AND SW VA...MUCH WHERE
IT WAS YESTERDAY.
PREVIOUS DISCUSSION BELOW...
WEAK UPPER LOW CUTS THROUGH THE CWA THIS EVENING. BEST MOISTURE
AND DYNAMICS POSITIONED SOUTH OF KCRW. LATEST VIS IMAGERY SHOW LOW
LEVEL CLOUD DECK IS INCHING TOWARD THE WV-KY LINE AS OF 17Z. MADE
MINIMAL ADJUSTMENTS TO POPS AND CLOUD THROUGH THIS EVENING.
BROUGHT CLOUDS A LITTLE FURTHER NORTH AND WEST. MAIN FORECAST
PROBLEM WILL BE TIMING AND PLACEMENT OF STRATUS DECK...AND THE
INTERPLAY WITH OVERNIGHT MINS AND TUESDAY MAX TEMPS. THE CLOUD
BOUNDARY SHOULD BE FAIRLY SHARP. SYSTEM SHOULD EXIT AFTER 6Z
LEAVING WEAK HIGH PRESSURE IN ITS WAKE.
SLIGHT CLEARING FOR TUESDAY MORNING AS NEXT WAVE APPROACHES.
MODELS HAVE BACKED OFF ON INCREASING CLOUDS FROM THE WEST ON
TUESDAY SO SLOWED TIMING OF INCREASING CLOUDS TUESDAY AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
MODELS INDICATE TWO UPPER LEVEL DISTURBANCES WILL PUSH SOUTHEAST
ACROSS THE AREA...FIRST ONE FROM TUESDAY NIGHT INTO WEDNESDAY AND
ANOTHER ON THURSDAY.
LATEST RUNS SUGGEST ONSET OF ANY MEASURABLE PRECIP WILL BE SLOWER
THAN PREVIOUSLY THOUGHT AND GRIDS HAVE BEEN TWEAKED TO REFLECT THIS
THINKING. WHILE THERE ARE TIMING DIFFERENCES...ALL MODELS...AS
WELL AS HPC...INDICATE MEASURABLE PRECIP WILL OCCUR ACROSS PORTIONS
OF THE REGION TUESDAY NIGHT INTO WEDNESDAY. WITH THIS IN
MIND...HAVE BUMPED POPS UP TO LIKELY.
WITH SURFACE HIGH PRESSURE BUILDING IN FROM THE WEST...PRECIP
CHANCES SHOULD END ACROSS THE LOWLANDS LATE WEDNESDAY INTO
THURSDAY. COMBINATION OF NEXT SHORTWAVE...SUFFICIENT LOW-LEVEL
MOISTURE AND NORTHWEST WINDS...SHOULD KEEP PRECIPITATION CHANCES IN
THE MOUNTAINS WEDNESDAY NIGHT INTO THURSDAY.
MAV/MET GUIDANCE FOR LOWS IS CLOSE TO OUR FORECASTED NUMBERS...SO
ONLY TWEAKED MADE. MAV/MET NUMBERS FOR HIGHS ON WEDNESDAY ARE
WARMER THAN PREVIOUS NUMBERS...BUT MAY BE A LITTLE TOO WARM BECAUSE
OF CLOUDS AND PRECIP. HAVE TWEAKED NUMBERS UP IN A FEW LOCATIONS...
BUT DID NOT BITE OFF ON THE WARMER MAV NUMBERS.
USED A BLEND OF MEX NUMBERS AND HPC VALUES FOR HIGHS ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
OPERATIONAL MODELS ADVERTISING A CLIPPER SYSTEM TO COME THROUGH THE
FIRST PART OF THE WEEKEND. QPF AMOUNTS WILL GENERALLY BE ON THE
LIGHT SIDE...WITH SOME SNOW EXPECTED...BUT SYSTEM WILL BE A QUICK
MOVER. COULD LEAVE SOME LINGERING UPSLOPE ON THE BACK SIDE THROUGH
THE DAY SATURDAY AND EARLY INTO SATURDAY NIGHT. THIS SYSTEM WILL
ALSO SERVE TO USHER IN A MORE WINTER LIKE AIRMASS AS 925MB
TEMPERATURES DROP TO AROUND 10C BELOW ZERO. WILL EXPECT A CLEAR
NIGHT SATURDAY NIGHT...AND WILL SEE MOST LOCATIONS DROPPING INTO THE
TEENS WHILE MOUNTAIN VALLEYS ARE IN THE HUNT FOR SINGLE DIGITS. HIGH
PRESSURE SETTLES IN FOR THE REMAINDER OF THE LONG TERM WITH
TEMPERATURES SLOW TO REBOUND THROUGH THIS PERIOD.
&&
.AVIATION /06Z TUESDAY THROUGH 06Z WEDNESDAY/...
AREAS OF LOW STRATUS ACROSS THE NORTHERN MTNS WILL DISSIPATE
09-10Z. SOME MVFR CIGS POSSIBLE FOR KEKN UP TO 09Z.
OTHERWISE A CLEAR SKY WILL PREVAIL FOR MOST THRU 12Z. EXCEPTION BEING
ACROSS PORTIONS OF SE OH WHERE A LOW STRATUS DECK...MARKED BY A
WIND SHIFT IN LWR LEVELS WILL ADVANCE 10-12Z BEFORE HALTING
PROGRESS S AND E.
DRIER AIR ADVECTING IN FORM OF LWR DWPTS ACROSS THE NORTH WILL
TEND TO MITIGATE FG DEVELOPMENT THRU 12Z. FURTHER S...HIGHER DWPTS
ALONG WITH A RELAXING BL WIND SHOULD ALLOW FOR RVR VALLEY FG TO
FORM ONCE AGAIN EARLY THIS MORNING. CENTRAL/SOUTHERN WV AND SW VA
STAND ONCE AGAIN FOR DENSE FG. SHOULD BE A LITTLE LATER FORMING
THAN YESTERDAY DUE SOME RESIDUAL BL WINDS. FOR TAF SITES...KEPT LIFR FZFG
CONFINED TO KCRW...WITH IFR VSBY POSSIBLE OVER TOWARD KHTS.
ANY FOG ACROSS CENTRAL/SOUTHERN WV AND SW VA WILL QUICKLY LIFT AND
SCT OUT FOR VFR CONDITIONS THROUGH THE REST OF THE PERIOD.
WILL SEE LITTLE PROGRESS IN ADVANCEMENT OF STRATUS ACROSS SE
OH...UNTIL AFTER 18Z WHEN SOME MVFR CIGS MAY SNEAK INTO KPKB.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: TIMING AND INTENSITY OF FOG COULD VARY OVER CENTRAL
AND SOUTHERN AREAS. TIMING AND EXTENT OF LOW STRATUS OVER SE OH
COULD VARY THRU 18Z.
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 TUE 02/07/12
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 L L L L L L H H H
HTS CONSISTENCY H H H L L L L M L H H H
BKW CONSISTENCY H H H L L H H H H H H H
EKN CONSISTENCY H M M L L L L L L H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z WEDNESDAY...
IFR POSSIBLE IN THE MOUNTAINS DUE TO SNOW SHOWERS LATE TUESDAY NIGHT
INTO WEDNESDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...KMC/30
SHORT TERM...JSH
LONG TERM...26
AVIATION...30
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
820 PM CST WED FEB 8 2012
.DISCUSSION.../ISSUED AT 825 PM CST/
ONLY PROBLEM REMAINS STRATUS ON THE SOUTH END OF FORECAST AREA. IN
LIGHT OF SHORT TERM MODELS WILL CONTINUE TO PLAY IT TO PUSH SLOWLY
EAST AND SLIGHTLY INTO FORECAST AREA INCLUDING YANKTON TO ESPECIALLY
SIOUX CITY. HRRR TRIES TO DEVELOP IT NORTHEAST LATE TO THE AREA FROM
FSD NORTH AND EAST BUT WITH NO SNOW COVER AND ADVANCING DRY AIR AND
SUBSIDENCE...THINK IT WILL STAY OUT OF ALL BUT THE FAR SOUTH. THIS
MODEL TRIED TO DEVELOP SUCH A SEPARATE AREA A FEW NIGHTS AGO WITH
THE LOWER STRATUS AND FOG IN THE DRY AIR TOO FAR NORTH AND THAT
FAILED TO DEVELOP. SO FOR THE AREA EXCEPT THE FAR SOUTH CLEAR SHOULD
CONTINUE. TEMPERATURES LOOK OK WITH THE LIGHT WARMING LOW LEVEL
FLOW PREVENTING A DROP WELL DOWN INTO THE SINGLE DIGITS AS WE HAD
LAST NIGHT. / WILLIAMS
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
THE MAIN AVIATION ISSUE TONIGHT WILL BE IF ANY STRATUS IN NEBRASKA
SNEAKS UP INTO OUR SOUTHERN ZONES. WITH A LIGHT S TO SW FLOW OF LOW
LEVEL AIR...THERE IS DEFINITELY A THREAT OF THAT HAPPENING...WITH
CEILINGS IN THE LOWER END MVFR TO UPPER END IFR RANGE. IF THIS
HAPPENS...IT WOULD MAINLY AFFECT OUR ZONES ALONG THE MISSOURI RIVER
CORRIDOR. IT APPEARS AT THE MOMENT THAT DRY AIR IS AFFECTING THE
KSUX TAF SITE...SO STRATUS MAY NOT BE IMMINENT AT THAT SITE. HOWEVER
THE RUC40...NAM12 AND HRRR ARE ALL STRONGLY HINTING AT STRATUS
MOVING INTO THE KSUX TAF SITE AROUND 09Z LATE TONIGHT...LASTING
THROUGH ABOUT 15Z THURSDAY. SO WILL MONITOR. WIND WISE...A STRONG
COLD FRONT WILL BE EDGING THROUGH THIS FORECAST AREA LATE THURSDAY
AND THURSDAY NIGHT. THEREFORE THE WINDS WILL SHIFT TO THE N AND NW
IN OUR NORTHERN ZONES THURSDAY AFTERNOON...PROCEEDING SOUTHWARD
THROUGH THURSDAY EVENING. /MJF
&&
.PREV DISCUSSION.../ISSUED AT 316 PM CST/
STRATUS CONTINUES TO NIP AT THE SOUTHERN BORDER OF THE CWA THIS
AFTERNOON AND EXPECT THIS TREND TO CONTINUE THROUGH THE NIGHT. WHILE
THE NORTHERN EDGE IS DISSIPATING...EXPECT THAT A RESURGENCE TO THE
NORTH WILL OCCUR TONIGHT AS THE INVERSION STRENGTHENS AND THE WINDS
REMAIN LIGHT SOUTH TO SOUTHWEST WHICH SHOULD AID IN ADVECTING TO THE
EAST AND NORTHEAST. FOR NOW WILL KEEP NEAR AND ALONG THE MISSOURI
RIVER BUT THIS WILL NEED TO BE WATCHED AS IT COULD CREEP NORTHWARD
AHEAD OF DEVELOPING WEST WINDS FOR THURSDAY. OTHERWISE...DID NOT
CHANGE LOWS TOO MUCH...JUST WARMED A BIT IN THE SOUTH WITH THE
POTENTIAL STRATUS...BUT MAINLY TEENS.
STILL PLANNING ON A MILD AND NOT TOO BREEZY DAY THURSDAY AHEAD OF
THE NEXT COLD FRONT. WEST WINDS SHOULD AVERAGE ABOUT 15 TO 20 MPH.
LOW LEVEL THERMAL FIELD NOT TOO IMPRESSIVE HOWEVER SO WARMEST HIGHS
LIKELY ONLY INTO THE MID 40S...BUT STILL 15 DEGREES OR SO ABOVE
NORMAL. /08
COLD FRONT EXITS THE FORECAST AREA ON THURSDAY NIGHT WITH A SURGE OF
MUCH COLDER AIR ARRIVING LATE AT NIGHT AND INTO FRIDAY. BRISK NORTH
WINDS ARE EXPECTED BEHIND THE FRONT...TURNING NORTHEASTERLY ON
FRIDAY BEFORE GRADUALLY DIMINISHING THROUGH THE DAY. DRY WEATHER
WILL PREVAIL WITH ONLY SOME INCREASED CLOUD COVERAGE FOLLOWING THE
FRONT. LOWS WILL FALL MAINLY INTO THE SINGLE DIGITS FOLLOWED BY
HIGHS ONLY RECOVERING INTO THE LOWER TEENS IN THE NORTHEAST TO NEAR
20 INTO THE MO VALLEY. FRIDAY NIGHT AND SATURDAY WILL PAINT A
SIMILAR PICTURE AS ARCTIC HIGH PRESSURE GRADUALLY SINKS SOUTHWARD
FROM CANADA AND SITS OVERHEAD BY SATURDAY AFTERNOON.
RIDGING BUILDS INTO THE CENTRAL STATES ON SUNDAY WITH THE SURFACE
HIGH SINKING SOUTHEAST OF THE CWA. THE RESULTANT RETURN FLOW WILL
ALLOW SOME WARMING OF THE AIRMASS AND TEMPERATURES TO RETURN TO NEAR
NORMALS IN THE UPPER 20S. A MID LEVEL SHORTWAVE FOLLOWS SUNDAY NIGHT
THROUGH MONDAY WHICH INTRODUCES A CHANCE FOR LIGHT SNOWFALL MAINLY
EAST OF I29. WITH BOTH THE GFS AND ECMWF SHOWING SOME DECENT FORCING
NEAR OUR SOUTHERN AND EASTERN BORDER...WENT AHEAD AND BUMPED UP POPS
ABOUT 10 PERCENT HIGHER THAN THE ALLBLEND.
NEAR SEASONAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
EARLY NEXT WEEK. MODELS A BIT UNCERTAIN ABOUT A POTENTIAL CUT OFF
LOW WHICH IS NOW TRENDING WELL SOUTH OF THE FORECAST AREA. GIVEN THE
LARGE CHANGE FROM THE PREVIOUS MODEL RUNS...LEFT SOME SLIGHT CHANCE
POPS FROM THE ALLBLEND IN FOR TUESDAY NIGHT AND WEDNESDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
550 PM CST WED FEB 8 2012
.DISCUSSION.../ISSUED AT 316 PM CST/
STRATUS CONTINUES TO NIP AT THE SOUTHERN BORDER OF THE CWA THIS
AFTERNOON AND EXPECT THIS TREND TO CONTINUE THROUGH THE NIGHT. WHILE
THE NORTHERN EDGE IS DISSIPATING...EXPECT THAT A RESURGENCE TO THE
NORTH WILL OCCUR TONIGHT AS THE INVERSION STRENGTHENS AND THE WINDS
REMAIN LIGHT SOUTH TO SOUTHWEST WHICH SHOULD AID IN ADVECTING TO THE
EAST AND NORTHEAST. FOR NOW WILL KEEP NEAR AND ALONG THE MISSOURI
RIVER BUT THIS WILL NEED TO BE WATCHED AS IT COULD CREEP NORTHWARD
AHEAD OF DEVELOPING WEST WINDS FOR THURSDAY. OTHERWISE...DID NOT
CHANGE LOWS TOO MUCH...JUST WARMED A BIT IN THE SOUTH WITH THE
POTENTIAL STRATUS...BUT MAINLY TEENS.
STILL PLANNING ON A MILD AND NOT TOO BREEZY DAY THURSDAY AHEAD OF
THE NEXT COLD FRONT. WEST WINDS SHOULD AVERAGE ABOUT 15 TO 20 MPH.
LOW LEVEL THERMAL FIELD NOT TOO IMPRESSIVE HOWEVER SO WARMEST HIGHS
LIKELY ONLY INTO THE MID 40S...BUT STILL 15 DEGREES OR SO ABOVE
NORMAL. /08
COLD FRONT EXITS THE FORECAST AREA ON THURSDAY NIGHT WITH A SURGE OF
MUCH COLDER AIR ARRIVING LATE AT NIGHT AND INTO FRIDAY. BRISK NORTH
WINDS ARE EXPECTED BEHIND THE FRONT...TURNING NORTHEASTERLY ON
FRIDAY BEFORE GRADUALLY DIMINISHING THROUGH THE DAY. DRY WEATHER
WILL PREVAIL WITH ONLY SOME INCREASED CLOUD COVERAGE FOLLOWING THE
FRONT. LOWS WILL FALL MAINLY INTO THE SINGLE DIGITS FOLLOWED BY
HIGHS ONLY RECOVERING INTO THE LOWER TEENS IN THE NORTHEAST TO NEAR
20 INTO THE MO VALLEY. FRIDAY NIGHT AND SATURDAY WILL PAINT A
SIMILAR PICTURE AS ARCTIC HIGH PRESSURE GRADUALLY SINKS SOUTHWARD
FROM CANADA AND SITS OVERHEAD BY SATURDAY AFTERNOON.
RIDGING BUILDS INTO THE CENTRAL STATES ON SUNDAY WITH THE SURFACE
HIGH SINKING SOUTHEAST OF THE CWA. THE RESULTANT RETURN FLOW WILL
ALLOW SOME WARMING OF THE AIRMASS AND TEMPERATURES TO RETURN TO NEAR
NORMALS IN THE UPPER 20S. A MID LEVEL SHORTWAVE FOLLOWS SUNDAY NIGHT
THROUGH MONDAY WHICH INTRODUCES A CHANCE FOR LIGHT SNOWFALL MAINLY
EAST OF I29. WITH BOTH THE GFS AND ECMWF SHOWING SOME DECENT FORCING
NEAR OUR SOUTHERN AND EASTERN BORDER...WENT AHEAD AND BUMPED UP POPS
ABOUT 10 PERCENT HIGHER THAN THE ALLBLEND.
NEAR SEASONAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
EARLY NEXT WEEK. MODELS A BIT UNCERTAIN ABOUT A POTENTIAL CUT OFF
LOW WHICH IS NOW TRENDING WELL SOUTH OF THE FORECAST AREA. GIVEN THE
LARGE CHANGE FROM THE PREVIOUS MODEL RUNS...LEFT SOME SLIGHT CHANCE
POPS FROM THE ALLBLEND IN FOR TUESDAY NIGHT AND WEDNESDAY.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
THE MAIN AVIATION ISSUE TONIGHT WILL BE IF ANY STRATUS IN NEBRASKA
SNEAKS UP INTO OUR SOUTHERN ZONES. WITH A LIGHT S TO SW FLOW OF LOW
LEVEL AIR...THERE IS DEFINITELY A THREAT OF THAT HAPPENING...WITH
CEILINGS IN THE LOWER END MVFR TO UPPER END IFR RANGE. IF THIS
HAPPENS...IT WOULD MAINLY AFFECT OUR ZONES ALONG THE MISSOURI RIVER
CORRIDOR. IT APPEARS AT THE MOMENT THAT DRY AIR IS AFFECTING THE
KSUX TAF SITE...SO STRATUS MAY NOT BE IMMINENT AT THAT SITE. HOWEVER
THE RUC40...NAM12 AND HRRR ARE ALL STRONGLY HINTING AT STRATUS
MOVING INTO THE KSUX TAF SITE AROUND 09Z LATE TONIGHT...LASTING
THROUGH ABOUT 15Z THURSDAY. SO WILL MONITOR. WIND WISE...A STRONG
COLD FRONT WILL BE EDGING THROUGH THIS FORECAST AREA LATE THURSDAY
AND THURSDAY NIGHT. THEREFORE THE WINDS WILL SHIFT TO THE N AND NW
IN OUR NORTHERN ZONES THURSDAY AFTERNOON...PROCEEDING SOUTHWARD
THROUGH THURSDAY EVENING. /MJF
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
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.
&&
$$
07/DANIELS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
856 PM EST WED FEB 8 2012
.SYNOPSIS...
LOW PRESSURE NEAR THE COAST OF THE CAROLINAS WILL CONTINUE TO
TRACK EAST AND OFFSHORE TONIGHT. HIGH PRESSURE BUILDS IN FOR
THURSDAY AND MUCH OF FRIDAY BEFORE AN ARCTIC COLD FRONT CROSSES
THE APPALACHIANS FRIDAY NIGHT INTO SATURDAY BRINGING MOUNTAIN SNOW
SHOWERS ALONG WITH MUCH COLDER AIR. HIGH PRESSURE FOLLOWS THE
FRONT WITH DRIER AIR AND A SLOW MODERATION IN TEMPERATURES FOR
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 830 PM EST WEDENSDAY...
EVENING SOUNDINGS SHOW THE FLOW TURNING MORE UPSLOPISH TONIGHT WITH
RATHER DEEP MOISTURE UNDER THE INVERSION UP TO NEAR 7H. HOWEVER
DESPITE THE COLUMN BEING BELOW FREEZING...MOISTURE ON THE WESTERN
SLOPES HAS BECOME A BIT MORE SHALLOW ALLOWING THE FORMATION OF
MORE FREEZING DRIZZLE AND SNOW GRAINS THIS EVENING. HOWEVER PRECIP
COVERAGE REMAINS RATHER LIMITED GIVEN THE FLOW STILL A BIT TOO
WESTERLY AND BETTER MOISTURE BASICALLY CUT OFF TO THE EAST WITH
THE LOW OFFSHORE. LATEST LOCAL RNK WRF AND RUC ALSO DEPICTS MUCH LESS
UPSLOPE -SHSN COVERAGE AFTER MIDNIGHT WITH THE 85H FLOW TURNING
MORE NORTHERLY. THUS TRIMMED BACK TO LOW CHANCE POPS LATER
TONIGHT MAINLY FAR NW AFTER CURRENT SMALL BANDS FADE THIS EVENING.
ALSO INCLUDING A PERIOD OF SOME LIGHT MIX BASED ON SPOTTER REPORTS
FROM AROUND BLF AND OFF AND ON REPORTING OF UP/-FZRA IN OBS FROM
OUT WEST. WILL ALSO KEEP IN SOME ISOLATED -SHSN MENTION AS FAR
EAST AS THE NEW RIVER VALLEY THRU LATE THIS EVENING BEFORE DRYING
ALOFT WINS OUT. CLOUDS REMAIN SLOW TO GO ACROSS THE SOUTH/EAST AND
WITH MODELS TOO FAST TO ERODE VIA DOWNSLOPE...KEPT LOW CLOUDS IN
FOR A FEW MORE HOURS...WITH A GRADUAL EROSION BACK TO ALONG THE
BLUE RIDGE EXPECTED AFTER MIDNIGHT. BACKED OFF LOWS A LITTLE
ESPCLY WHERE CLOUDS LIKELY TO PERSIST LONGER ON HOLD TEMPS UP SOME
DESPITE WEAK COLD ADVECTION OVERNIGHT. SPS ALSO OUT TO MAKE
MENTION OF ICY SPOTS DUE TO CURRENT LIGHT PRECIP AND OVERNIGHT
BLACK ICE FROM EARLIER MELTING AND REFREEZING.
AS OF 300 PM EST WEDNESDAY...
WITH THIS MORNING`S DISTURBANCE PASSING EAST...MUCH OF THE
SNOW/RAIN IS FINISHED. HOWEVER...WINDS VEER MORE TO THE NW SOMEWHAT
ACROSS SE WEST VA AND ANOTHER SHRTWV APPROACHES FROM IN/IL THIS
EARLY EVENING. SNOW SHOWERS ARE POSSIBLE IN THE LWB/BLF CORRIDOR
WITH THIS WAVE...AND MAY BE SOME FLURRIES INTO THE NEW RIVER
VALLEY AND NW NC. AFTER MIDNIGHT...WINDS DECREASE SUCH THAT ONLY
CLOUDS AND A SNOW SHOWER ACROSS WESTERN GREENBRIER IS EXPECTED.
THE AFOREMENTIONED DISTURBANCE COULD PUT DOWN A FRESH COATING AT
BLF/LWB...AND MAYBE AN INCH OR TWO IN WESTERN GREENBRIER. SNOW MAY
BEGIN TO STICK TO ROADS WITH TEMPS FALLING INTO THE 20S AND ROADS
WHICH ARE NOW WET MAY DEVELOP ICY PATCHES. ALTHOUGH THE GROUND IS
STILL RATHER WARM AND THIS IS NOT GOING TO BE A FLASH FREEZE.
WINDS MAY GUST TO 30 MPH EARLY TONIGHT IN NW NC. OVERCAST WILL
HOLD ALONG THE HIGHLANDS OF SE WEST VA THURSDAY...THEN CLEAR BY
LATE MORNING WITH PLENTY OF SUNSHINE AND HIGHS IN THE LOW TO UPPER
40S...A FEW DEGREES BELOW GUIDANCE.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM EST WEDNESDAY...
HIGH PRESSURE CONTINUES TO MOVE EAST THURSDAY NIGHT INTO FRIDAY.
FLOW AROUND THE HIGH WILL RESULT IN WESTERLY WINDS FOR OUR REGION.
LOW TEMPERATURES THURSDAY NIGHT WILL BE NEAR NORMAL WITH READINGS
FROM THE UPPER TEENS IN THE NORTHWEST MOUNTAINS TO THE UPPER 20S IN
THE PIEDMONTS.
MOISTURE INCREASES ON FRIDAY IN ADVANCE OF AN APPROACHING COLD
FRONT. PLAYED HIGHS ON FRIDAY CLOSE TO ADJMETBC WITH READINGS
FROM THE MID 30S IN THE NORTHWEST MOUNTAINS TO THE MID 50S IN THE
SOUTHEAST. THE COLD FRONT WILL MOVE ACROSS THE AREA FRIDAY NIGHT
BRINGING SCATTERED RAIN/SNOW SHOWERS TO THE MOUNTAINS...WITH MAINLY
SPRINKLES/FLURRIES EAST OF THE BLUE RIDGE. SNOWFALL AMOUNTS WILL
GENERALLY BE LESS THAN AN INCH OR TWO. THE HIGHEST SNOW AMOUNTS WILL
FALL IN WESTERN GREENBRIER COUNTY. LOW TEMPERATURES FRIDAY NIGHT
WILL RANGE FROM THE UPPER TEENS IN THE NORTHWEST MOUNTAINS TO THE
MID 30S IN SOUTHSIDE.
ON SATURDAY...PREVAILING NORTHWEST FLOW WILL HELP MAINTAIN SNOW
SHOWERS AND SNOW FLURRIES ACROSS THE MOUNTAINS. ADDITIONAL SNOWFALL
AMOUNTS UP TO AN INCH ARE POSSIBLE. 85H WINDS ON THE GFS AND ECMWF
ARE PROGGED TO BE IN THE 35 TO 40 KT RANGES ACROSS THE WEST. WE MAY
SEE SOME SURFACE GUSTS UP TO 35 MPH AT HIGHER ELEVATIONS. THE
PRESSURE RISES ON THE ECMWF ARE NOTEWORTHY. WINDS SHOULD REMAIN
BELOW ADVISORY LEVELS ACROSS THE HIGHEST ELEVATIONS. COLD AND
WINDY ON SATURDAY WITH HIGHS FROM THE MID 20S IN THE WEST TO MID 40S
IN THE EAST. THE SNOW SHOWERS AND SNOW FLURRIES WILL GRADUALLY
DECREASE IN COVERAGE AND END SATURDAY AFTERNOON INTO SATURDAY NIGHT.
LOWERED MINIMUM TEMPERATURES FOR SATURDAY NIGHT FROM THE SINGLE
DIGITS TO THE LOWER 20S IN THE SOUTHEAST. WIND CHILLS BELOW ZERO ARE
POSSIBLE IN THE HIGHEST ELEVATIONS OF THE NORTHWEST MOUNTAINS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 237 PM EST WEDNESDAY...
AFTER A BREEZY SUNDAY MORNING...COLD HIGH PRESSURE WILL BUILD INTO
THE REGION. THIS RIDGE SLIDES OFF THE MID ATLANTIC COAST MONDAY
NIGHT. A FEW SHOWERS MAY ACCOMPANY A WARM FRONT ON TUESDAY. A COLD
FRONT APPROACHES FROM THE WEST ON WEDNESDAY TO INCREASE SHOWERS
CHANCES.
TEMPERATURES SUNDAY WILL BE BLUSTERY AND 10F-15F BELOW NORMAL.
TEMPERATURES MODERATE TOWARD SEASONAL LEVELS ON MONDAY. THE PASSING
OF THE WARM FRONT TUESDAY WILL ALLOW TEMPERATURES TO WARM INTO THE
UPPER 40S TO LOWER 50S. BEING AHEAD OF A COLD FRONT
WEDNESDAY...TEMPERATURES COULD JUMP 10-15F ABOVE NORMAL.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
AS OF 555 PM EST WEDNESDAY...
BANDS OF VERY LIGHT SNOW SHOWERS CONTINUE ACROSS THE WEST THIS
EVENING AND WILL LIKELY PERSIST INTO THE OVERNIGHT ESPCLY ACROSS
THE SE WVA LOCATIONS AS BRIEF UPSLOPE KICKS IN. THIS WILL RESULT
IN MVFR/IFR CIGS AT KBLF/KLWB OVERNIGHT INTO EARLY THU...AND
PERIODIC MVFR AT KBCB WITH MAINLY VFR CIGS FROM KROA AND POINTS
EAST TONIGHT. INTERMITTENT VSBY REDUCTIONS ARE ALSO POSSIBLE
ESPCLY SE WVA AROUND KBLF OVERNIGHT WITH A PERIOD OR TWO OF MVFR
POSSIBLE IN -SHSN BANDS. STRONGER NW WINDS ALSO POSSIBLE BEHIND
THE DEPARTING LOW THIS EVENING WITH GUSTS TO 25-30 MPH MAINLY
ALONG THE KBLF-KBCB-KROA CORRIDOR THRU MIDNIGHT.
FLURRIES END THURS MORNING AT KBLF/KLWB...WITH CIGS BECOMING BKN
AND RISING ABV 3KFT PERHAPS. THURSDAY AND FRIDAY RETURN TO
VFR...BEFORE AN ARCTIC COLD FRONT PRODUCES SNOW SHOWERS AND BRINGS
MVFR/IFR RESTRICTIONS TO LWB/BLF FRIDAY NIGHT THROUGH SAT NIGHT.
HIGH PRESSURE AND VFR RETURNS SUNDAY AND MONDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/KM
NEAR TERM...JH/KM
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/JH/KM
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1156 AM CST TUE FEB 7 2012
.UPDATE...HAVE REDUCED POPS QUITE A BIT IN THE FAR SOUTHEAST
COUNTIES...AS THE LAKE EFFECT SNOW SHOWERS HAVE HAD A TOUGH TIME
DEVELOPING. NORTHEAST FETCH IS FAVORABLE...WITH DELTA T VALUES
BORDERLINE AT 12 TO 13 DEGREES CELSIUS. THE MOIST LAYER DOES NOT
EXTEND TO THE 12 BELOW ZERO CELSIUS ISOTHERM...AND THE 850MB TO
700MB LAYER IS QUITE DRY. THESE ARE LIKELY KEEPING ANY SIGNIFICANT
SNOW SHOWERS FROM FORMING.
THUS...EXPECT JUST ISOLATED TO SCATTERED LIGHT SNOW SHOWERS AND
FLURRIES IN THIS AREA THROUGH THE REST OF THE DAY...WITH LITTLE TO
NO ADDITIONAL ACCUMULATIONS. SCATTERED FLURRIES SHOULD ALSO LINGER
ELSEWHERE INTO MID AFTERNOON...BEFORE SLOWLY DECREASING LATER THIS
AFTERNOON FROM NORTH TO SOUTH.
DRIER AIRMASS PUSHING SOUTH THROUGH THE AREA WILL BRING CLEARING
FROM NORTH TO SOUTH LATE THIS AFTERNOON AND TONIGHT. NEAR STEADY
TEMPERATURES ARE EXPECTED THIS AFTERNOON WITH THE CLOUDS AND WEAK
COLD AIR ADVECTION. BRISK NORTHEAST WINDS SHOULD GRADUALLY SUBSIDE
BY EARLY THIS EVENING.
&&
.AVIATION/18Z TAFS/...MVFR CEILINGS ARE EXPECTED TO LINGER THIS
AFTERNOON INTO THIS EVENING ACROSS TAF SITES. AN ISOLATED LIGHT
SNOW SHOWER MAY AFFECT MILWAUKEE AND KENOSHA INTO THE LATE
AFTERNOON...BUT SHOULD NOT PRODUCE ANY ACCUMULATIONS. FLURRIES ARE
MORE LIKELY DURING THIS TIME.
MVFR CEILINGS SHOULD MIX OUT FROM NORTH TO SOUTH BY 02Z TO 03Z
WEDNESDAY...WITH SKIES BECOMING CLEAR LATER TONIGHT AND THROUGH
WEDNESDAY. GUSTY NORTHEAST WINDS WILL LINGER THROUGH LATE
AFTERNOON BEFORE WEAKENING AND BACKING NORTH TO NORTHWEST TONIGHT.
THESE WINDS WILL THEN SHIFT WEST ON WEDNESDAY.
&&
.MARINE...SMALL CRAFT ADVISORY CONTINUES UNTIL THIS EVENING FOR
THE NORTH HALF OF THE NEARSHORE WATERS...AND UNTIL LATER TONIGHT FOR
THE SOUTH HALF. BRISK NORTHEAST WINDS OF 15 TO 25 KNOTS...WITH
GUSTS TO 30 KNOTS...ARE EXPECTED THROUGH TODAY. THESE WINDS WILL
BACK NORTH TO NORTHWEST TONIGHT AND WEAKEN. SUBSEQUENT HIGH WAVES
WILL LINGER THIS AFTERNOON AND THIS EVENING...THEN SUBSIDE FROM
NORTH TO SOUTH ACROSS THE WATERS AFTER MIDNIGHT.
&&
.PREV DISCUSSION... /ISSUED 211 AM CST TUE FEB 7 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
MID/UPPER LEVEL TROUGH ACROSS THE NORTHERN GREAT LAKES REGION IS
EXPECTED TO DROP SOUTH AS AN UPPER LOW OVER THE CENTRAL ROCKIES
PUSHES EAST. MAIN PORTION OF THE NORTHERN TROUGH HEADS EAST TONIGHT
AS THE WESTERN SHORTWAVE MOVES ACROSS KENTUCKY. WEAK 700 MB UPWARD
MOTION MAINLY THIS MORNING THEN WEAKENING BY EVENING. RELATIVE
HUMIDITY AT 700 MB IS BELOW 50 PCT. 850 MB RH INCREASES AS IT DROPS
SOUTH ACROSS SOUTHERN WISCONSIN...REACHING ABOVE 90 PCT. 00Z NAM IS
NOT AS COLD AT 850 MB AS PRIOR MODELS. -8 DEG C DROPS DOWN INTO
NORTHERN PORTIONS OF THE FORECAST AREA BY 12Z AND NEARS THE ILLINOIS
BORDER BY 18Z. HOWEVER BY THE TIME DELTA T VALUES BECOME FAVORABLE
FOR LAKE SNOW...LOW LEVEL MOISTURE IS DECREASING FROM THE NORTH.
HOWEVER MOISTURE EXTENDS TO NEAR 5 THSD FT AND DESPITE MARGINAL
LAPSE RATES...THERE IS STILL THE POSSIBILITY FOR A PERIOD OF LAKE
SNOW.
NO ORGANIZED SNOW BAND ON THE HRRR AND 12 HOUR PRECIP QPF VALUES ARE
DOWN TO 0.05 INCHES ON THE NAM AND 0.07 ON THE HRRR. WILL THEREFORE
GO WITH MAINLY AN INCH OR SO OF LAKE EFFECT.
LATER TONIGHT THE HIGH PRESSURE RIDGE MOVES INTO SOUTHERN WISCONSIN
WITH DIMINISHING WINDS. NAM HAS NO QPF AS LOW LEVELS CONTINUE TO
DRY AND LOW LEVEL LAPSE RATES DECREASE TO AROUND 7.5 C/KM BELOW 900
MB.
WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE...HIGH
HIGH PRESSURE WILL SIT JUST TO THE SOUTHWEST OF THE FORECAST AREA
WEDNESDAY AND WEDNESDAY NIGHT...BEFORE BEGINNING TO SHIFT SOUTH
THURSDAY AHEAD OF APPROACHING LOW PRESSURE. HIGH CLOUDS ARE EXPECTED
TO DECREASE WEDNESDAY MORNING...WITH SKIES BECOMING MOSTLY SUNNY
BY AFTERNOON. MOSTLY CLEAR SKIES SHOULD HOLD ON THROUGH MUCH OF
THE DAY THURSDAY...WITH CLOUDS POSSIBLY MOVING IN FROM THE
NORTHWEST IN THE AFTERNOON AS THE SYSTEM DRAWS NEAR.
LEANED TOWARD THE MILDER END OF MODELS WED/THU WITH THE LACK OF
SNOW COVER AND THE OVERALL RESULTANT MODEL COLD BIAS THIS WINTER.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
WENT WITH A SLIGHT CHANCE FOR SNOW ACROSS THE EAST THURSDAY NIGHT
AND FRIDAY AS THE SFC COLD FRONT AND UPPER TROUGH SWING THROUGH.
KEPT POPS ON THE LOW END...AS THE NAM IS THE MOST AGGRESSIVE WITH QPF
BUT IS ONLY SATURATED UP TO AROUND 10 KFT. CURRENT FRONT TIMING
WOULD RESULT IN TEMPS FALLING THROUGH MUCH OF THE DAY AS COLDER AIR
ADVECTS IN BEHIND THE FRONT.
SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
STILL EXPECTING THE WEEKEND INTO EARLY NEXT WEEK TO BE DRY. SHOULD
SEE BELOW NORMAL TEMPS BEHIND THE DEPARTING SYSTEM
SATURDAY...WARMING TO NEAR NORMAL FOR SUNDAY AND MONDAY.
AVIATION/12Z TAFS/...
MVFR CIGS/VSBYS BEHIND COLD FRONT EXITING SOUTHERN WISCONSIN. IFR
CIGS SOUTH AND SOUTHWEST OF MADISON EARLY THIS MORNING. VSBYS
SHOULD IMPROVE TO VFR AS COLDER AND DRIER LOW LEVEL AIR MOVES IN.
SOME LAKE EFFECT SNOW POSSIBLE THIS MORNING AND INTO THE AFTERNOON.
HOWEVER 850 MB TEMPS TO LAKE SURFACE TEMPERATURES ARE MARGINAL AND
BY THE TIME THEY COOL DRIER AIR BEGINS TO FILTER IN FROM THE NORTH.
HOWEVER MOISTURE EXTENDS TO NEAR 5 THSD FT AND DESPITE MARGINAL
LAPSE RATES...THERE IS STILL THE POSSIBILITY FOR A PERIOD OF LAKE
SNOW.
MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT INTO TONIGHT. BRISK
NE WINDS AND ASSOCIATED HIGH WAVES WILL DEVELOP. THE WINDS WILL
BEGIN TO SUBSIDE THIS EVENING...BUT DUE TO THE NORTHEAST
FETCH...HIGH WAVES WILL LINGER A LITTLE LONGER.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 AM CST WEDNESDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LMZ643-644.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
WEDNESDAY THROUGH MONDAY...DDV
AREA FORECAST DISCUSSION...UPDATED
NWS LA CROSSE WI
628 AM CST TUE FEB 7 2012
.SHORT TERM...UPDATE
628 AM CST TUE FEB 7 2012
A SECONDARY COLD FRONT IS DROPPING THROUGH THE REGION AND HAS
BROUGHT A SMALL BAND OF VERY LIGHT DRIZZLE ALONG WITH IT. THESE
LIGHT REFLECTIVITIES CAN BE SEEN ON KARX DROPPING SOUTH ACROSS
WESTERN WISCONSIN AND THROUGH SOUTHEAST MINNESOTA. BASED ON LAPS
SOUNDINGS FROM ACROSS THE REGION...THE SATURATED LAYER IS
SUPERCOOLED AT BETWEEN -3C TO -5C...SO THERE IS NO ICE PRESENT
WITH IT. AS LOW LEVEL TEMPERATURES CONTINUE TO COOL THROUGH THE
MORNING...SOME FLURRIES MAY START TO FALL...BUT DRIZZLE WILL BE
THE MAIN PRECIPITATION TYPE THROUGH AT LEAST THE EARLY MORNING
HOURS HERE. THIS DRIZZLE IS VERY LIGHT BUT WITH TEMPERATURES
BELOW FREEZING THERE IS SOME CONCERN THAT A FEW ICY SPOTS COULD
FORM ON AREA ROADWAYS GOING INTO THE MORNING COMMUTE. ZFP UPDATE
COMING OUT SHORTLY.
TODAY THROUGH THURSDAY NIGHT
316 AM CST TUE FEB 7 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS AND FLURRIES TODAY. FOCUS THEN
TURNS TO TEMPERATURES TONIGHT INTO THURSDAY.
LATEST WATER VAPOR IMAGERY SHOWED A BROAD UPPER LEVEL LOW OVER THE
CENTRAL PLAINS...DRIFTING SOUTHEAST TOWARD THE MIDDLE MISSISSIPPI
RIVER VALLEY. CURRENT SURFACE OBSERVATIONS PLACED A COLD FRONT
STRETCHING FROM NEAR CHICAGO...WEST THROUGH SOUTHERN IOWA. STRATUS
HAS SPREAD ACROSS THE FORECAST AREA IN THE WAKE OF THE
FRONT...PRODUCING CLOUDY SKIES.
IN ADDITION TO THE STRATUS ACROSS THE AREA THIS MORNING....MID TO
HIGH CLOUDS WILL SPREAD ACROSS SOUTHEAST MINNESOTA...NORTHEAST
IOWA...AND FAR SOUTHWEST WISCONSIN AS THE UPPER LOW MOVES FROM THE
CENTRAL PLAINS INTO THE MID MISSISSIPPI RIVER VALLEY. SURFACE HIGH
PRESSURE IS EXPECTED TO GRADUALLY BUILD INTO THE AREA TODAY WITH
THE STRATUS DECK DISSIPATING ACROSS NORTHERN WISCONSIN EARLY THIS
AFTERNOON. THE STRATUS WILL CONTINUE TO DISSIPATE SOUTHWARD THIS
AFTERNOON...TO THE INTERSTATE 90 CORRIDOR BY LATE AFTERNOON INTO
EARLY EVENING. SHOULD SEE A DECREASE IN CLOUDS AS THE HIGH MOVES
IN. HIGH CLOUDS ARE EXPECTED TO LINGER ACROSS NORTHEAST IOWA
THROUGH SOUTHERN WISCONSIN BEFORE FINALLY EXITING TO THE EAST
TONIGHT. FORECAST SOUNDINGS ARE SHOWING THE POTENTIAL FOR SOME
LIGHT FLURRIES ACROSS THE ENTIRE FORECAST AREA THIS
MORNING...SHIFTING SOUTH OF INTERSTATE 90 THIS AFTERNOON. HAVE
KEPT FLURRIES ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST
WISCONSIN...AND REMOVED THEM NORTH OF THESE LOCATIONS FOR THE
AFTERNOON HOURS...GIVEN THE DRY AIR MOVING IN FROM THE NORTH. PLAN
ON HIGH TEMPERATURES RANGING FROM THE THE MID 20S ACROSS NORTH
CENTRAL WISCONSIN TO THE UPPER 20S TO AROUND 30 ACROSS NORTHEAST
IOWA.
THE HIGH WILL BUILD INTO THE FORECAST AREA TONIGHT PROVIDING MOSTLY
CLEAR SKIES AND QUIET WEATHER. LOOK FOR LOWS TO RANGE FROM THE
SINGLE DIGITS ACROSS NORTH CENTRAL WISCONSIN TO THE MID TEENS ACROSS
NORTHEAST IOWA. GIVEN THE DRYNESS OF THE AIRMASS MOVING IN...DEWPOINTS
IN THE SINGLE DIGITS TO SINGLE DIGITS BELOW ZERO...COULD SEE A FEW
LOW LYING AREAS DIP TO AROUND ZERO WITH THE CLEAR SKIES AND IF
WINDS DECOUPLE.
SURFACE HIGH PRESSURE WILL BE IN CONTROL ON WEDNESDAY...WITH MOSTLY
SUNNY SKIES AND HIGH TEMPERATURES RANGING FROM THE MID 20S TO AROUND
30. PLAN ON LIGHT AND VARIABLE WINDS IN THE MORNING...INCREASING TO
8 TO 12 MPH BY LATE MORNING INTO THE AFTERNOON HOURS AS THE HIGH
SLIDES SOUTH AND A COLD FRONT APPROACHES FROM SOUTHERN
MANITOBA/ONTARIO. LOOK FOR LOW TEMPERATURES TO FALL INTO THE TEENS
WEDNESDAY NIGHT UNDER MOSTLY CLEAR SKIES.
CLOUDS WILL INCREASE ACROSS THE FORECAST AREA LATE THURSDAY
AFTERNOON AS THE COLD FRONT/UPPER LEVEL TROUGH APPROACH THE AREA
FROM SOUTHERN CANADA. ONE LAST WARM DAY IS IN STORE ON THURSDAY
BEFORE THE FRONT MOVES IN. PLAN ON HIGH TEMPERATURES IN THE 30S ON
THURSDAY. THE COLD FRONT IS EXPECTED TO MOVE IN THURSDAY NIGHT. NAM
FORECAST SOUNDINGS INDICATE LIGHT SNOW/SNOW SHOWERS MAY DEVELOP
THURSDAY NIGHT AS THE FRONT MOVES IN. THE GFS SUGGESTS THE COLD
FRONTAL PASSAGE WILL LIKELY BE DRY...WITH POSSIBLY A FEW FLURRIES
MOVING THROUGH. WILL MAINTAIN DRY FORECAST GIVEN THE MAJORITY OF
GUIDANCE IS NOT PRODUCING PRECIPITATION...BUT WILL HAVE TO KEEP AN
EYE ON THIS GIVEN HOW COLD THE AIRMASS IS. 850 MB TEMPERATURES ON
THURSDAY ARE AROUND -4 C...THEN FALL TO -16 C LATE THURSDAY NIGHT
INTO EARLY FRIDAY.
.LONG TERM...FRIDAY THROUGH MONDAY
316 AM CST TUE FEB 7 2012
07.00 MODELS SHOW COOL HIGH PRESSURE SETTLING OVER THE AREA ON
FRIDAY WITH TEMPERATURES FALLING TO SLIGHTLY BELOW NORMAL VALUES.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE LOWER TEENS ACROSS
NORTHERN WISCONSIN TO THE LOWER 20S ACROSS NORTHEAST IOWA. COOL
TEMPERATURES AND QUIET WEATHER IS ANTICIPATED SATURDAY WITH COOL
HIGH PRESSURE IN PLACE AT THE SURFACE...AND COLD CYCLONIC FLOW
ALOFT ACROSS THE GREAT LAKES. PLAN ON ANOTHER DAY OF HIGHS IN THE
LOWER TEENS TO LOW 20S. LOOK FOR OVERNIGHT LOWS BOTH FRIDAY AND
SATURDAY...TO FALL INTO THE SINGLE DIGITS ABOVE ZERO. LOW LYING
AREAS COULD SEE LOW TEMPERATURES FALL INTO THE SINGLE DIGITS BELOW
ZERO. SLIGHTLY WARMER TEMPERATURES ARE EXPECTED ON SUNDAY AS THE
UPPER TROUGH SLIDES EAST AND A WARMER AIR MASS EDGES IN FROM THE
NORTHERN PLAINS. HIGHS ON SUNDAY WILL RANGE FROM THE LOWER 20S
ACROSS NORTHERN WISCONSIN TO THE UPPER 20S ACROSS NORTHEAST IOWA.
THE SLIGHT WARM UP WILL CONTINUE INTO MONDAY WITH 850 MB
TEMPERATURES WARMING FROM AROUND -15 C ON SUNDAY...TO -10 C ON
MONDAY. GFS/ECMWF SHOW A SHORTWAVE TROUGH MOVING ACROSS THE
CENTRAL/SOUTHERN PLAINS INTO THE MID/LOWER MISSISSIPPI RIVER
VALLEY. HAVE REMOVED PRECIPITATION CHANCES ON MONDAY...GIVEN A
MORE SOUTHERN SOLUTION.
&&
.AVIATION...TODAY AND TONIGHT
530 AM CST TUE FEB 7 2012
THE MAIN FOCUS AT THE TAF SITES IS ON THE 2KFT MVFR STRATUS DECK
THAT IS IN PLACE FROM THE GREAT LAKES WEST THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY AND CENTRAL PLAINS. THESE CLOUDS ARE IN
THE WAKE OF A COLD FRONT THAT HAS DROPPED INTO CENTRAL ILLINOIS
WITH SURFACE WINDS OUT OF THE NORTHEAST AND GUSTING UP TO 20KT.
SOME FLURRIES WILL BE POSSIBLE THIS MORNING...BUT WILL BE LIGHT
ENOUGH THAT VISIBILITY WILL NOT DROP BELOW P6SM.
THE MAIN TASK IS FIGURING OUT WHEN THE MVFR CEILINGS WILL GO VFR
AND CLEAR OUT. 07.10Z RUC FORECAST SOUNDINGS AND 950-850MB
RELATIVE HUMIDITY FIELDS INDICATE THAT THE LOW LEVEL MOISTURE
LIKELY WILL NOT DRY UP UNTIL LATER THIS MORNING DUE TO A MOISTURE FEED
FROM LAKE SUPERIOR. THUS...HAVE PUSHED BACK THE CLIMB OUT OF MVFR
UNTIL LATE THIS AFTERNOON INTO THE EARLY EVENING.
WITH A RIDGE OF HIGH PRESSURE MOVING INTO THE REGION
TONIGHT...WINDS WILL GO LIGHT AND VARIABLE WITH JUST SOME HIGH
LEVEL CLOUD COVER TO CONTEND WITH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
316 AM CST TUE FEB 7 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 AM CST TUE FEB 7 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
316 AM CST TUE FEB 7 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS AND FLURRIES TODAY. FOCUS THEN
TURNS TO TEMPERATURES TONIGHT INTO THURSDAY.
LATEST WATER VAPOR IMAGERY SHOWED A BROAD UPPER LEVEL LOW OVER THE
CENTRAL PLAINS...DRIFTING SOUTHEAST TOWARD THE MIDDLE MISSISSIPPI
RIVER VALLEY. CURRENT SURFACE OBSERVATIONS PLACED A COLD FRONT
STRETCHING FROM NEAR CHICAGO...WEST THROUGH SOUTHERN IOWA. STRATUS
HAS SPREAD ACROSS THE FORECAST AREA IN THE WAKE OF THE
FRONT...PRODUCING CLOUDY SKIES.
IN ADDITION TO THE STRATUS ACROSS THE AREA THIS MORNING....MID TO
HIGH CLOUDS WILL SPREAD ACROSS SOUTHEAST MINNESOTA...NORTHEAST
IOWA...AND FAR SOUTHWEST WISCONSIN AS THE UPPER LOW MOVES FROM THE
CENTRAL PLAINS INTO THE MID MISSISSIPPI RIVER VALLEY. SURFACE HIGH
PRESSURE IS EXPECTED TO GRADUALLY BUILD INTO THE AREA TODAY WITH
THE STRATUS DECK DISSIPATING ACROSS NORTHERN WISCONSIN EARLY THIS
AFTERNOON. THE STRATUS WILL CONTINUE TO DISSIPATE SOUTHWARD THIS
AFTERNOON...TO THE INTERSTATE 90 CORRIDOR BY LATE AFTERNOON INTO
EARLY EVENING. SHOULD SEE A DECREASE IN CLOUDS AS THE HIGH MOVES
IN. HIGH CLOUDS ARE EXPECTED TO LINGER ACROSS NORTHEAST IOWA
THROUGH SOUTHERN WISCONSIN BEFORE FINALLY EXITING TO THE EAST
TONIGHT. FORECAST SOUNDINGS ARE SHOWING THE POTENTIAL FOR SOME
LIGHT FLURRIES ACROSS THE ENTIRE FORECAST AREA THIS
MORNING...SHIFTING SOUTH OF INTERSTATE 90 THIS AFTERNOON. HAVE
KEPT FLURRIES ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST
WISCONSIN...AND REMOVED THEM NORTH OF THESE LOCATIONS FOR THE
AFTERNOON HOURS...GIVEN THE DRY AIR MOVING IN FROM THE NORTH. PLAN
ON HIGH TEMPERATURES RANGING FROM THE THE MID 20S ACROSS NORTH
CENTRAL WISCONSIN TO THE UPPER 20S TO AROUND 30 ACROSS NORTHEAST
IOWA.
THE HIGH WILL BUILD INTO THE FORECAST AREA TONIGHT PROVIDING MOSTLY
CLEAR SKIES AND QUIET WEATHER. LOOK FOR LOWS TO RANGE FROM THE
SINGLE DIGITS ACROSS NORTH CENTRAL WISCONSIN TO THE MID TEENS ACROSS
NORTHEAST IOWA. GIVEN THE DRYNESS OF THE AIRMASS MOVING IN...DEWPOINTS
IN THE SINGLE DIGITS TO SINGLE DIGITS BELOW ZERO...COULD SEE A FEW
LOW LYING AREAS DIP TO AROUND ZERO WITH THE CLEAR SKIES AND IF
WINDS DECOUPLE.
SURFACE HIGH PRESSURE WILL BE IN CONTROL ON WEDNESDAY...WITH MOSTLY
SUNNY SKIES AND HIGH TEMPERATURES RANGING FROM THE MID 20S TO AROUND
30. PLAN ON LIGHT AND VARIABLE WINDS IN THE MORNING...INCREASING TO
8 TO 12 MPH BY LATE MORNING INTO THE AFTERNOON HOURS AS THE HIGH
SLIDES SOUTH AND A COLD FRONT APPROACHES FROM SOUTHERN
MANITOBA/ONTARIO. LOOK FOR LOW TEMPERATURES TO FALL INTO THE TEENS
WEDNESDAY NIGHT UNDER MOSTLY CLEAR SKIES.
CLOUDS WILL INCREASE ACROSS THE FORECAST AREA LATE THURSDAY
AFTERNOON AS THE COLD FRONT/UPPER LEVEL TROUGH APPROACH THE AREA
FROM SOUTHERN CANADA. ONE LAST WARM DAY IS IN STORE ON THURSDAY
BEFORE THE FRONT MOVES IN. PLAN ON HIGH TEMPERATURES IN THE 30S ON
THURSDAY. THE COLD FRONT IS EXPECTED TO MOVE IN THURSDAY NIGHT. NAM
FORECAST SOUNDINGS INDICATE LIGHT SNOW/SNOW SHOWERS MAY DEVELOP
THURSDAY NIGHT AS THE FRONT MOVES IN. THE GFS SUGGESTS THE COLD
FRONTAL PASSAGE WILL LIKELY BE DRY...WITH POSSIBLY A FEW FLURRIES
MOVING THROUGH. WILL MAINTAIN DRY FORECAST GIVEN THE MAJORITY OF
GUIDANCE IS NOT PRODUCING PRECIPITATION...BUT WILL HAVE TO KEEP AN
EYE ON THIS GIVEN HOW COLD THE AIRMASS IS. 850 MB TEMPERATURES ON
THURSDAY ARE AROUND -4 C...THEN FALL TO -16 C LATE THURSDAY NIGHT
INTO EARLY FRIDAY.
.LONG TERM...FRIDAY THROUGH MONDAY
316 AM CST TUE FEB 7 2012
07.00 MODELS SHOW COOL HIGH PRESSURE SETTLING OVER THE AREA ON
FRIDAY WITH TEMPERATURES FALLING TO SLIGHTLY BELOW NORMAL VALUES.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE LOWER TEENS ACROSS
NORTHERN WISCONSIN TO THE LOWER 20S ACROSS NORTHEAST IOWA. COOL
TEMPERATURES AND QUIET WEATHER IS ANTICIPATED SATURDAY WITH COOL
HIGH PRESSURE IN PLACE AT THE SURFACE...AND COLD CYCLONIC FLOW
ALOFT ACROSS THE GREAT LAKES. PLAN ON ANOTHER DAY OF HIGHS IN THE
LOWER TEENS TO LOW 20S. LOOK FOR OVERNIGHT LOWS BOTH FRIDAY AND
SATURDAY...TO FALL INTO THE SINGLE DIGITS ABOVE ZERO. LOW LYING
AREAS COULD SEE LOW TEMPERATURES FALL INTO THE SINGLE DIGITS BELOW
ZERO. SLIGHTLY WARMER TEMPERATURES ARE EXPECTED ON SUNDAY AS THE
UPPER TROUGH SLIDES EAST AND A WARMER AIR MASS EDGES IN FROM THE
NORTHERN PLAINS. HIGHS ON SUNDAY WILL RANGE FROM THE LOWER 20S
ACROSS NORTHERN WISCONSIN TO THE UPPER 20S ACROSS NORTHEAST IOWA.
THE SLIGHT WARM UP WILL CONTINUE INTO MONDAY WITH 850 MB
TEMPERATURES WARMING FROM AROUND -15 C ON SUNDAY...TO -10 C ON
MONDAY. GFS/ECMWF SHOW A SHORTWAVE TROUGH MOVING ACROSS THE
CENTRAL/SOUTHERN PLAINS INTO THE MID/LOWER MISSISSIPPI RIVER
VALLEY. HAVE REMOVED PRECIPITATION CHANCES ON MONDAY...GIVEN A
MORE SOUTHERN SOLUTION.
&&
.AVIATION...TODAY AND TONIGHT
530 AM CST TUE FEB 7 2012
THE MAIN FOCUS AT THE TAF SITES IS ON THE 2KFT MVFR STRATUS DECK
THAT IS IN PLACE FROM THE GREAT LAKES WEST THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY AND CENTRAL PLAINS. THESE CLOUDS ARE IN
THE WAKE OF A COLD FRONT THAT HAS DROPPED INTO CENTRAL ILLINOIS
WITH SURFACE WINDS OUT OF THE NORTHEAST AND GUSTING UP TO 20KT.
SOME FLURRIES WILL BE POSSIBLE THIS MORNING...BUT WILL BE LIGHT
ENOUGH THAT VISIBILITY WILL NOT DROP BELOW P6SM.
THE MAIN TASK IS FIGURING OUT WHEN THE MVFR CEILINGS WILL GO VFR
AND CLEAR OUT. 07.10Z RUC FORECAST SOUNDINGS AND 950-850MB
RELATIVE HUMIDITY FIELDS INDICATE THAT THE LOW LEVEL MOISTURE
LIKELY WILL NOT DRY UP UNTIL LATER THIS MORNING DUE TO A MOISTURE FEED
FROM LAKE SUPERIOR. THUS...HAVE PUSHED BACK THE CLIMB OUT OF MVFR
UNTIL LATE THIS AFTERNOON INTO THE EARLY EVENING.
WITH A RIDGE OF HIGH PRESSURE MOVING INTO THE REGION
TONIGHT...WINDS WILL GO LIGHT AND VARIABLE WITH JUST SOME HIGH
LEVEL CLOUD COVER TO CONTEND WITH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
316 AM CST TUE FEB 7 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
211 AM CST TUE FEB 7 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
MID/UPPER LEVEL TROUGH ACROSS THE NORTHERN GREAT LAKES REGION IS
EXPECTED TO DROP SOUTH AS AN UPPER LOW OVER THE CENTRAL ROCKIES
PUSHES EAST. MAIN PORTION OF THE NORTHERN TROUGH HEADS EAST TONIGHT
AS THE WESTERN SHORTWAVE MOVES ACROSS KENTUCKY. WEAK 700 MB UPWARD
MOTION MAINLY THIS MORNING THEN WEAKENING BY EVENING. RELATIVE
HUMIDITY AT 700 MB IS BELOW 50 PCT. 850 MB RH INCREASES AS IT DROPS
SOUTH ACROSS SOUTHERN WISCONSIN...REACHING ABOVE 90 PCT. 00Z NAM IS
NOT AS COLD AT 850 MB AS PRIOR MODELS. -8 DEG C DROPS DOWN INTO
NORTHERN PORTIONS OF THE FORECAST AREA BY 12Z AND NEARS THE ILLINOIS
BORDER BY 18Z. HOWEVER BY THE TIME DELTA T VALUES BECOME FAVORABLE
FOR LAKE SNOW...LOW LEVEL MOISTURE IS DECREASING FROM THE NORTH.
HOWEVER MOISTURE EXTENDS TO NEAR 5 THSD FT AND DESPITE MARGINAL
LAPSE RATES...THERE IS STILL THE POSSIBILITY FOR A PERIOD OF LAKE
SNOW.
NO ORGANIZED SNOW BAND ON THE HRRR AND 12 HOUR PRECIP QPF VALUES ARE
DOWN TO 0.05 INCHES ON THE NAM AND 0.07 ON THE HRRR. WILL THEREFORE
GO WITH MAINLY AN INCH OR SO OF LAKE EFFECT.
LATER TONIGHT THE HIGH PRESSURE RIDGE MOVES INTO SOUTHERN WISCONSIN
WITH DIMINISHING WINDS. NAM HAS NO QPF AS LOW LEVELS CONTINUE TO
DRY AND LOW LEVEL LAPSE RATES DECREASE TO AROUND 7.5 C/KM BELOW 900
MB.
.WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE...HIGH
HIGH PRESSURE WILL SIT JUST TO THE SOUTHWEST OF THE FORECAST AREA
WEDNESDAY AND WEDNESDAY NIGHT...BEFORE BEGINNING TO SHIFT SOUTH
THURSDAY AHEAD OF APPROACHING LOW PRESSURE. HIGH CLOUDS ARE EXPECTED
TO DECREASE WEDNESDAY MORNING...WITH SKIES BECOMING MOSTLY SUNNY
BY AFTERNOON. MOSTLY CLEAR SKIES SHOULD HOLD ON THROUGH MUCH OF
THE DAY THURSDAY...WITH CLOUDS POSSIBLY MOVING IN FROM THE
NORTHWEST IN THE AFTERNOON AS THE SYSTEM DRAWS NEAR.
LEANED TOWARD THE MILDER END OF MODELS WED/THU WITH THE LACK OF
SNOW COVER AND THE OVERALL RESULTANT MODEL COLD BIAS THIS WINTER.
.THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
WENT WITH A SLIGHT CHANCE FOR SNOW ACROSS THE EAST THURSDAY NIGHT
AND FRIDAY AS THE SFC COLD FRONT AND UPPER TROUGH SWING THROUGH.
KEPT POPS ON THE LOW END...AS THE NAM IS THE MOST AGGRESSIVE WITH QPF
BUT IS ONLY SATURATED UP TO AROUND 10 KFT. CURRENT FRONT TIMING
WOULD RESULT IN TEMPS FALLING THROUGH MUCH OF THE DAY AS COLDER AIR
ADVECTS IN BEHIND THE FRONT.
.SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
STILL EXPECTING THE WEEKEND INTO EARLY NEXT WEEK TO BE DRY. SHOULD
SEE BELOW NORMAL TEMPS BEHIND THE DEPARTING SYSTEM
SATURDAY...WARMING TO NEAR NORMAL FOR SUNDAY AND MONDAY.
&&
.AVIATION/12Z TAFS/...
MVFR CIGS/VSBYS BEHIND COLD FRONT EXITING SOUTHERN WISCONSIN. IFR
CIGS SOUTH AND SOUTHWEST OF MADISON EARLY THIS MORNING. VSBYS
SHOULD IMPROVE TO VFR AS COLDER AND DRIER LOW LEVEL AIR MOVES IN.
SOME LAKE EFFECT SNOW POSSIBLE THIS MORNING AND INTO THE AFTERNOON.
HOWEVER 850 MB TEMPS TO LAKE SURFACE TEMPERATURES ARE MARGINAL AND
BY THE TIME THEY COOL DRIER AIR BEGINS TO FILTER IN FROM THE NORTH.
HOWEVER MOISTURE EXTENDS TO NEAR 5 THSD FT AND DESPITE MARGINAL
LAPSE RATES...THERE IS STILL THE POSSIBILITY FOR A PERIOD OF LAKE
SNOW.
&&
.MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT INTO TONIGHT. BRISK
NE WINDS AND ASSOCIATED HIGH WAVES WILL DEVELOP. THE WINDS WILL
BEGIN TO SUBSIDE THIS EVENING...BUT DUE TO THE NORTHEAST
FETCH...HIGH WAVES WILL LINGER A LITTLE LONGER.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 AM CST WEDNESDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LMZ643-644.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
WEDNESDAY THROUGH MONDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CST MON FEB 6 2012
.SHORT TERM...OVERNIGHT
941 PM CST MON FEB 6 2012
THE 07.00Z NAM/WRF AND LATEST RUC SOUNDINGS SHOW GENERALLY DRY AIR
BELOW 800 FEET WHEN THE BEST LIFT IS MOVING INTO THE REGION.
LOOKING AT THE TOP OF SOUNDINGS...THE TEMPERATURES ARE COLD ENOUGH
FOR SOME ICE CRYSTALS INTRODUCTION. THEREFORE IF THERE IS
PRECIPITATION IT WOULD BE IN THE FORM OF FLURRIES...THUS...REMOVED
THE FREEZING DRIZZLE FROM THE FORECAST. WITH THERE BEING NO REPORTS OF
PRECIPITATION UPSTREAM...BEGINNING TO WONDER IF THE MODELS ARE
OVERDOING THE MOISTURE A BIT. HOWEVER NOT CONFIDENT ENOUGH TO
REMOVE THE FLURRIES FROM THE FORECAST AT THIS TIME.
ALSO BEEN NOTICING THAT THE TEMPERATURES ARE RISING AS THE CLOUDS
MOVE INTO THE AREAS FROM THE NORTH. THE NAM/WRF SEEMS TO HAVE A
GOOD HANDLE ON THIS...SO TRENDED THE HOURLY GRIDS THAT WAY. IT DID
NOT MAKE A HUGE CHANGE IN THE FORECAST MINIMUM TEMPERATURES...BUT
THE HOURLY TEMPERATURE TRACES WILL BETTER REFLECT REALITY.
.LONG TERM...FRIDAY THROUGH MONDAY
252 PM CST MON FEB 6 2012
06.12Z ECMWF AND GFS BOTH SHOW ANOTHER SHOT OF COLD AIR DROPPING
INTO THE REGION ON FRIDAY BEHIND THE AFOREMENTIONED COLD FRONT AS
HIGH PRESSURE BUILDS ACROSS THE PLAINS. THIS WILL KEEP TEMPERATURES
AT OR BELOW NORMAL FOR SATURDAY INTO SUNDAY WITH DRY WEATHER. HOW
MUCH MODERATION OCCURS SUNDAY AND MONDAY ARE THE BIG DIFFERENCES IN
THE MODELS. GFS QUICKER IN TAKING TROUGH OVER THE AREA EASTWARD AND
BUILDING THE RIDGE IN. HENCE 850MB TEMPERATURES CLIMB TO AROUND 0
MONDAY...WILE THE ECMWF KEEPS THE COLDER AIR ENTRENCHED WITH 850MB
TEMPERATURES AROUND -8 CELSIUS. BOTH DO GENERATE A LITTLE
PRECIPITATION ON THE BACK SIDE OF THE HIGH MONDAY...BUT TYPE IS A
PROBLEM AT THIS POINT BASED ON TEMPERATURES. THUS WENT WITH A CHANCE
OF RAIN OR SNOW.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1140 PM CST MON FEB 6 2012
AT 11 PM...COLD FRONT EXTENDED FROM IOWA FALLS...IOWA /KIFA/ TO
MILWAUKEE. WINDS SOUTH OF THIS FRONT WERE WESTERLY. MEANWHILE TO
ITS NORTH...THE WINDS WERE NORTH AND NORTHEAST. THESE WERE HELPING
BRINGING SOME LAKE INDUCED CLOUDS INTO THE FORECAST AREA. CEILINGS
ARE MAINLY VFR SOUTH OF INTERSTATE 94...AND FROM 1500-2500 FEET TO
THE NORTH OF THIS CORRIDOR. THINKING THAT THE CEILINGS WILL
GRADUALLY BECOME MVFR BETWEEN 0730Z AND 0900Z AT BOTH TAF
SITES...AND REMAIN THERE THROUGH THE EARLY AFTERNOON.
WITH THE MOISTURE LOOKING A BIT MORE SHALLOWER THAN WHAT THE
SOUNDINGS ARE INDICATING AND NO REPORTS OF SNOW UPSTREAM...REMOVED
THE MENTION OF SNOW IN THE TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
252 PM CST MON FEB 6 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...RABERDING
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
434 PM MST WED FEB 8 2012
.AVIATION...
SATELLITE IMAGERY SHOWS A MIDLEVEL CLOUD DECK ESSENTIALLY SOUTH OF
A DOUGLAS TO SCOTTSBLUFF LINE. THESE VFR CIGS WILL PERSIST THROUGH
AROUND 12Z. MOST OF THE MODEL GUIDANCE KEEPS LOW CLOUDS TO THE
EAST OF KSNY AND KAIA OVERNIGHT...HOWEVER THERE IS A LOW CHANCE THAT
IFR/MVFR CIGS COULD EXIST DURING THE MORNING HOURS AT THESE SITES.
DID NOT INCLUDE IN THE TAFS DUE TO THE LOW PROBABILITY.
OTHERWISE...NW WINDS WILL STRENGTHEN DURING THURS AFTERNOON WITH
SUSTAINED WINDS 15 TO 25 KTS COMMON.
&&
.PREV DISCUSSION... /ISSUED 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 SLOWER 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.
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.
&&
$$
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1028 PM MST MON FEB 6 2012
.AVIATION...06Z TAFS
IFR CONDITIONS EXPECTED TO CONTINUE THROUGH LATE MORNING FOR MOST
LOCATIONS EAST OF THE LARAMIE RANGE IN NORTHEASTERLY UPSLOPING
WINDS AND LIGHT SNOW/SNOW FLURRIES. LATEST HRRR GUIDANCE SHOWING
LOW CLOUD DECK STARTING TO BREAK UP AFTER THE 13-14Z TIMEFRAME.
SINCE THIS GUIDANCE HAS BEEN SO GOOD RECENTLY...DECIDED TO FOLLOW
ITS GUIDANCE.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 326 PM MST MON FEB 6 2012/
SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...EARLY AFTERNOON
WATER VAPOR/SREF 500 MB COMPOSITE IMAGERY SHOWED THE BROAD UPPER
CYCLONIC CIRCULATION OVER COLORADO MOVING SLOWLY EASTWARD. SCATTERED
SNOW SHOWER ACTIVITY WAS ACCOMPANYING THIS FEATURE...MAINLY WEST
OF THE FRONT RANGE. THE OTHER FEATURE SEEN IN VISIBLE SATELLITE WAS
AN EXPANSIVE LOW CLOUD DECK MOVING SOUTHWARD THROUGH THE DAKOTAS
AND CENTRAL WYOMING BEHIND A SURFACE COLD FRONT. THIS FRONT WAS
ANALYZED FROM SOUTHERN SOUTH DAKOTA WESTWARD TO SOUTH OF DOUGLAS
AND CASPER THEN INTO NORTHWEST WYOMING. WINDS SHIFTED TO THE NORTH
AND INCREASED TO 20 TO 30 MPH AND GUSTY BEHIND THE FRONT. LIGHT SNOW
WAS OBSERVED AT BUFFALO AND SHERIDAN. TEMPERATURES AT 2 PM RANGED
FROM 45 AT CHADRON TO 21 AT VEDAUWOO.
SHORT RANGE MODEL TRENDS GENERALLY REMAIN CONSISTENT WITH THE GOING
FORECAST. THE 12Z GFS/ECMWF/GEM/NAM OPEN THE CLOSED UPPER LOW OVER
NORTHEAST COLORADO INTO A WAVE LATER TONIGHT...THEN EJECT IT EASTWARD
ACROSS THE PLAINS TUESDAY AND MIDWEST TUESDAY NIGHT. MEANWHILE...A
FAIRLY POTENT SHORTWAVE TROUGH ALONG THE NORTHERN TIER DROPS
SOUTHEAST THROUGH THE DAKOTAS AND MISSOURI VALLEY DURING THE SAME
TIME PERIOD. THE SURFACE COLD FRONT PRECEDING THE TROUGH WILL EXIT
THE CWA EARLY THIS EVENING. MOISTURE WRAPPING AROUND THE COLORADO LOW
AND WEAK UPSLOPE POST-FRONTAL FLOW WILL RESULT IN WIDESPREAD LIGHT
SNOW TONIGHT. ACCUMULATIONS WILL RANGE FROM ONE TO TWO INCHES FOR THE
LARAMIE AND SNOWY RANGES...WITH LESS THAN AN INCH ELSEWHERE. GUSTY
NORTHERLY WINDS THIS EVENING WILL DIMINISH AFTER MIDNIGHT...AND BE
LIGHT AND VARIABLE ON TUESDAY. THE SNOW WILL LINGER OVER THE NORTHERN
LARAMIE RANGE TUESDAY MORNING...THEN DIMINISH TUESDAY AFTERNOON AS
THE UPPER SUPPORT EXITS TO THE EAST. STRONG LOW LEVEL COLD AIR
ADVECTION (700 MB TEMPERATURES -14 TO -16C) AND CONSIDERABLE
CLOUDINESS WILL KEEP HIGH TEMPERATURES WELL BELOW NORMAL TUESDAY WITH
HIGHS IN THE TEENS AND 20S. CLEARING SKIES AND LIGHT WINDS WILL
PROVIDE EXCELLENT RADIATIONAL COOLING TUESDAY NIGHT WITH LOWS
DROPPING INTO THE SINGLE DIGITS AND LOWER TEENS. SOME OF THE VALLEY
LOCATIONS MAY REGISTER 0 TO 5 BELOW ZERO. FORTUNATELY THE BRUNT OF
THE COLDER AIRMASS ASSOCIATED WITH THE 1040 MB SURFACE HIGH PRESSURE
SYSTEM WILL AFFECT THE DAKOTAS AND UPPER MIDWEST. WEAK SURFACE AND
UPPER LEVEL RIDGING TO THE WEST WILL ALLOW THE WINDS TO BACK TO THE
WEST-NORTHWEST WEDNESDAY... WHICH WILL MODERATE TEMPERATURES ABOUT 10
DEGREES FROM TUESDAY/S HIGHS. BY WEDNESDAY AFTERNOON...A WEAK SURFACE
TROUGH WILL DEVELOP OVER EASTERN WYOMING. THE PRESSURE GRADIENT
ACROSS SOUTHEAST WYOMING TIGHTENS A BIT RESULTING IN BREEZY WEST-
SOUTHWEST WINDS ALONG AND WEST OF THE LARAMIE RANGE. IT WILL BE
MILDER WEDNESDAY NIGHT WITH LOWS MAINLY IN THE TEENS.
LONG TERM...THURSDAY THROUGH NEXT MONDAY...LONG RANGE MODELS
CONTINUE TO SHOW TRANQUIL CONDITIONS AND COOLER THAN NORMAL
TEMPERATURES LATE THIS WEEK...BUT ARE THEN INCONSISTENT AND IN
POOR AGREEMENT FOR THIS WEEKEND AS A SERIES OF UPPER LEVEL TROUGHS
MOVE ACROSS THE NORTHERN AND CENTRAL ROCKIES. MODELS AS WELL AS
THE ENSEMBLE FORECASTS ARE ALL TRENDING FURTHER EAST WITH THE
POTENTIAL ARCTIC OUTBREAK ACROSS THE GREAT PLAINS STATES FOR
FRIDAY...SO KEPT TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL. THE
ECMWF AND GEM ON THE OTHER HAND SHOW THIS ARCTIC FRONT HOLDING OFF
FOR ANOTHER DAY AND PUSHING INTO THE HIGH PLAINS OF WESTERN
NEBRASKA EARLY IN THE WEEKEND. BOTH MODELS SHOW THIS FRONTAL
BOUNDARY STALLING OVER THE HIGH PLAINS EAST OF THE LARAMIE RANGE
AS A WEAK UPPER LEVEL TROUGH QUICKLY MOVES EASTWARD FROM THE
PACIFIC NORTHWEST. WITH AMPLE LLVL CONVERGENCE ALONG THE
FRONT...UPSLOPE FLOW...AND COLD TEMPS...BOTH THE GEM AND ECMWF
SHOW SOME LIGHT SNOW MAINLY EAST OF THE LARAMIE RANGE THROUGH
SATURDAY NIGHT. INCREASED POP OVER THE AREA BUT KEPT MOST OF THE
FORECAST DRY FOR NOW SINCE THERE IS CONSIDERABLE DIFFERENCES
BETWEEN MODEL SOLUTIONS AS THE GFS SHOWS DRY WEATHER AS A RIDGE
ALOFT MOVES OVER THE CONTINENTAL DIVIDE. CONSIDERABLE DIFFERENCES
BETWEEN ENSEMBLE FORECASTS...SO THERE IS LIMITED CONFIDENCE IN
THIS WEEKENDS FORECAST. IF ANYTHING...MORE CONFIDENCE IN NEXT
WEEKS FORECAST WITH ALL MODELS SHOWING A LONG WAVE UPPER LEVEL
TROUGH SETTLING OVER MOST OF THE CENTRAL AND EVEN WESTERN UNITED
STATES AS MUCH COLDER AIR PUSHES SOUTH OVER THE INTER MOUNTAIN WEST
AND GREAT PLAINS STATES. AS THIS TIME...IT APPEARS THERE IS A
GREATER CHANCE FOR PRECIPITATION AND SNOWFALL EARLY NEXT WEEK AS
NUMEROUS PACIFIC STORM SYSTEMS PUSH ONSHORE AND ACROSS THE
NORTHERN AND CENTRAL ROCKIES.
&&
FIRE WEATHER...NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS. A
COLD FRONT WILL MOVE SOUTH THROUGH THE DISTRICTS BY EARLY THIS
EVENING...WITH GUSTY NORTH WINDS IN ITS WAKE. ALSO...AREAS OF LIGHT
SNOW WILL DEVELOP AND LINGER THROUGH TUESDAY MORNING. IT WILL BE
QUITE CHILLY TUESDAY AND TUESDAY NIGHT. ANOTHER COLD FRONT WILL MOVE
QUICKLY SOUTHEAST ACROSS THE PLAINS THURSDAY WITH ISOLATED SNOW
SHOWERS FOR THE MOUNTAINS. DRY WEATHER WITH SLOWLY MODERATING
TEMPERATURES CAN THEN BE EXPECTED THROUGH THE UPCOMING WEEKEND. THERE
WILL BE SOME BREEZY PERIODS ACROSS THE SOUTHEAST WYOMING FOR THE
LATTER HALF OF THE WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...JAMSKI
LONG TERM/AVIATION...TJT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
204 AM MST THU FEB 9 2012
.UPDATE...
UPDATED TO ADD A WINTER WEATHER ADVISORY FOR ZONE 18 FOR THE
REMAINDER OF TONIGHT INTO THE MIDDLE OF THE MORNING. SNOTELS WITHIN
THE HIGHWAY 550 CORRIDOR FROM OURAY SOUTH TO RED MOUNTAIN PASS
INDICATED AS MUCH AS 7 INCHES OF NEW SNOW HAS ACCUMULATED OVER THE
PAST FEW HOURS. AVALANCHE FORECASTER FROM THE SILVERTON OFFICE
REPORTED SNOWFALL RATES OF UP TO 2 INCHES PER HOUR. BASED ON
SATELLITE AND RUC ANALYSES...LIFT WAS JUST PEAKING OVER THIS AREA
AS THE SHORTWAVE TROUGH AXIS POISED TO MOVE EAST OF THE SAN JUANS
SHORTLY. THOUGH LARGE SCALE LIFT WILL DIMINISH...NORTHERLY FLOW ON
THE BACK SIDE OF THE TROUGH WILL CONTINUE TO GENERATE SUFFICIENT
OROGRAPHIC LIFT TO KEEP SNOW GOING ALONG THE 550 CORRIDOR SOUTH OF
RIDGWAY INTO THE MIDDLE OF THE MORNING. THIS SHOULD BRING 2 TO 5
ADDITIONAL INCHES AND THEREFORE HAVE ISSUED A WINTER WEATHER
ADVISORY FOR THIS AREA.
&&
.PREV DISCUSSION /ISSUED 846 PM MST WED FEB 8 2012/...
SHORT TERM /REST OF TONIGHT THROUGH FRIDAY/...
A FAST MOVING SHORTWAVE TROUGH WILL CONTINUE MOVING THROUGH THE
FORECAST AREA TONIGHT WITH PEAK QG FORCING AROUND MIDNIGHT OVER
WRN CO. MOISTURE WILL HAVE ALREADY INCREASED IN THE SWRLY FLOW
ALOFT TODAY WITH SPECIFIC HUMIDITY AROUND 3 G/KG. SYSTEM SEEMS TO
LACK A GREAT DEAL OF THERMAL SUPPORT WITH NO ORGANIZED SFC COLD
FRONT AND JET ENERGY PRETTY WELL REMOVED AS WELL. HOWEVER UPSTREAM
RIDGE IS AMPLIFYING AND THIS MEANS THE SHRT WV SHOULD BE IN THE
DEEPENING MODE. GENERALLY RAISED POPS AND INCREASED SNOW AMOUNTS
FOR OUR MTNS...BUT AMOUNTS STILL REMAIN BELOW ADVISORY CRITERIA.
BOTH THE GFS AND NAM SHOW THE MOST FAVORED LOCATION TO BE OVER THE
FLATTOPS WHERE 3-5 INCHES WILL BE COMMON WITH LOCALLY HIGHER
AMOUNTS.
THIS TROF QUICKLY DROPS TO THE SOUTHEAST THURSDAY AND THE FLOW
ALOFT VEERS TO THE NORTHWEST IN COLD ADVECTION PATTERN. EXPECT A
FEW SNOW SHOWERS TO LINGER OVER THE NORTH FACING SLOPES DURING THE
MORNING WITH ADDITIONAL LIGHT SNOW ACCUMULATIONS. BY AFTERNOON
SHWRS QUICKLY TAPER OFF AS LOW LEVEL LAPSE RATES STABILIZE. HEIGHTS
WILL BEGIN TO RISE THURSDAY NIGHT AS A RIDGE BUILDS OVER THE
DESERT SOUTHWEST. NO PRECIP IS EXPECTED BUT SOME HIGH CLOUDS MAY
DRIFT ACROSS THE NORTH.
AN INCREASINGLY MOIST NWRLY FLOW IS EXPECTED FRIDAY AND SOME
EMBEDDED VERY WEAK WAVES LIKELY TO ACT ON THIS MOISTURE. THE NAM IS
MUCH MORE ROBUST WITH DEVELOPING PRECIP...BUT IT APPEARS LIMITED
TO THE NRN MTNS. MEANWHILE THE GFS ESSENTIALLY KEEPS OUR CWA DRY.
WILL SORT OF COMPROMISE AND RAISE POPS TO THE ISOLATED CATEGORY
ACROSS THE NORTH TO COVER ANY SHWRS THAT MAY DEVELOP.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LONGWAVE RIDGE ALONG THE WEST COAST IS EXPECTED TO DE-AMPLIFY THIS
WEEKEND AND ALLOW PACIFIC ENERGY TO DROP INTO THE GREAT BASIN. THIS
SHOULD RESULT IN A SERIES OF DISTURBANCES AFFECTING THE FORECAST
AREA THROUGH THE MIDDLE OF NEXT WEEK. FORECAST CONFIDENCE IS GOOD
THROUGH MONDAY THEN LOWERS TUESDAY-WEDNESDAY AS MODEL DIFFERENCES
GROW.
NW FLOW WILL KEEP A CHANCE OF LIGHT SNOW IN THE NORTHERN CO MTNS FRI
NIGHT. FLOW ALOFT SHIFTS TO THE SOUTHWEST FOR SATURDAY AS A PACIFIC
SHORTWAVE TROUGH DIGS SOUTHWARD INTO NV. THIS TROUGH APPEARS TO
SPLIT WITH THE STRONGEST PIECE OF ENERGY DROPPING TO AZ SAT NIGHT
AND THEN MOVING EAST ACROSS NM ON SUNDAY. DECENT MOISTURE LOOKS TO
ACCOMPANY THIS SYSTEM. CLOUDS WILL BE ON THE INCREASE SATURDAY WITH
THE CHANCE OF PRECIPITATION INCREASING SATURDAY NIGHT IN WARM
ADVECTION. THE BEST CHANCE SHOULD BE ON SUNDAY AS THE TROUGH BODILY
MOVES ACROSS THE FORECAST AREA.
A TRANSIENT SHORTWAVE RIDGE SLIDES ACROSS ERN UT/WRN CO ON MONDAY AS
THE NEXT AND STRONGER LOOKING PACIFIC TROUGH DROPS INTO THE GREAT
BASIN. THIS TROUGH DEEPENS AS IT APPROACHES WITH THE 12Z GFS
BRINGING A CLOSED 500 MB LOW ACROSS THE 4 CORNERS ABOUT NOON ON
TUESDAY. 12Z CANADIAN MODEL HAS SIMILAR TIMING BUT TRACKS THE UPPER
LOW CENTER ALONG THE BOOKCLIFFS...WHILE THE 12Z ECMWF IS NOW SLOWER
THAN ITS PREVIOUS RUN AND DOESN/T BRING THE LOW/TROUGH ACROSS
SOUTHWEST CO UNTIL WED MORNING. WILL BUMP POPS UP FROM THE CONSENSUS
MODEL MON NIGHT THROUGH TUESDAY NIGHT BUT STILL KEEP IN IT IN THE
CHANCE CATEGORY DUE TO DIFFERENCES IN THE TIMING...BUT THIS STORM
COULD HAVE THE MAKINGS FOR SIGNIFICANT SNOW IN THE CENTRAL AND
SOUTHERN MTNS ESPECIALLY.
TEMPERATURES WILL VARY WITH THE PASSING STORMS...WARMING ON SATURDAY
AND MONDAY AHEAD OF THE TROUGHS AND THEN COOLING BEHIND THEM.
AVIATION /FOR 06Z TAF ISSUANCE/...
FLIGHT CONDITIONS WILL CONTINUE DETERIORATING OVERNIGHT AT ALL TAF SITES
AS CIGS LOWER WITH THE APPROACH OF THE NEXT FAST-MOVING SYSTEM.
MVFR CIGS/VIS IN AREAS OF -SN WILL CONTINUE OVER KGJT...KRIL...
KASE...AND KEGE WITH PERIODS OF IFR CIGS IN SN AND BR EXPECTED.
MOUNTAINS AND THE HIGHER PASSES WILL BE OBSCURED MOST OF THE NIGHT.
MVFR CONDITIONS IN -SN WITH OCCASIONALLY IFR CIGS WILL ALSO
CONTINUE AT KCAG/KHDN/KSBS. CONDITIONS WILL BE IMPROVING FROM THE
NORTHWEST ON THURSDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 018.
UT...NONE.
&&
$$
UPDATE.......NL
SHORT TERM...MC/CJC
LONG TERM....JAD
AVIATION.....JAD/CJC
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
250 AM EST Thu Feb 9 2012
.SYNOPSIS...
07Z water vapor and H4 RUC analysis shows an upper level pattern
along the northern Gulf coast dominated by southern stream flow.
Main belt of westerlies lies to our north helping to keep our
weather quiet...at least for today. Similar to the past several
days, WV imagery suggest we will continue to see periods of high
level cirrus streaming overhead to filter the sunshine. Looking
upstream, we see shortwave energy diving southeast across the
inter-mountain west toward the Southern Plains. It will be this
energy that will bring our next potential for showers Friday night
as it ejects quickly eastward and over our region.
At the surface,
1030mb high pressure is centered along the middle MS Valley this
morning. Our position well to its southeast results in a decent
gradient across the area, and is providing steady northerly breezes.
In response to the wind, our temperatures are a bit warmer than
previously expected. In fact, some spots that had dropped into the
middle 40s earlier, have rebounded several degrees in response to
the low level mixing.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
Today,
Dry and seasonably pleasant weather. Surface ridge will build south
through the day allowing the gradient to weaken. Our skies will
feature filtered sunshine as upper level moisture continues to
stream overhead in the form of cirrus. Less efficient mixing should
generally keep high temperatures a few degrees cooler than what was
experience Wednesday. Current grids show mid-afternoon temps
reaching the lower 60s north and middle to upper 60s south. Far
southeast portions of the Big Bend/Suwannee River Valley will make a
run at the lower 70s.
Tonight,
With the surface ridge center in closer proximity, will see a better
chance for low temps to fall into the middle to upper 30s late. Best
chances to reach these numbers will be west of the Suwannee River
Valley/I-75 corridor. Developing light easterly flow associated with
an organizing surface trough along the FL East Coast is expected to
transport a slight increase in Atlantic moisture into these far
eastern zones, and keep low temps in the lower/middle 40s. Current
numbers suggest only a minimal frost threat.
Friday,
Daylight hours of Friday will feature generally dry conditions with
increasing clouds. GFS has come around to support the earlier
solution of the ECMWF/CMC of a more well-defined mid-level shortwave
approaching from the west. As it appears now, deep layer synoptic
support/QG-forcing associated with this energy, along with the best
upper level jet configuration will not arrive until Friday
evening/night, and will keep shower chances out of the forecast.
Despite the increasing clouds, at least some filtered sunshine and a
weak thermal ridge ahead of the approaching system should allow
temperatures to rebound into the mid/upper 60s for most areas, and
upper 60s/lower 70s for the FL Big Bend.
Friday Night,
Shortwave trough will pivot across the area accompanied by an
impressive 150+kt jetstreak. Global guidance members are in good
agreement showing the best deep layer lift combination of QG forcing
and jet dynamics will come together over the southern half of the
area...and especially offshore. Current grids will show slight
chance 20% PoPs north, and chance 30-50% Pops south of a line
roughly from Panama City to Tallahassee and Valdosta. Rainfall
amounts look to be on the light side, from maybe a few hundredths of
an inch north, to potentially a couple tenths over the coastal
waters and SE Big Bend zones. System will be quite progressive and
expect best lift and moisture to be quickly exiting to our east
toward sunrise.
Saturday,
Clearing skies and a much cooler/drier airmass will be arriving on
NW winds in the wake of Friday Night`s system. Been a while since we
saw 850mb temps down to zero overhead, but ECMWF/GFS both show the
850 zero line arriving by the end of the day. Although the daylight
hours of Saturday will still see temps reaching the low/mid 60s,
Saturday Night and Sunday Nights will feature some rather chilly
readings, and light freeze potential. More details in the long term
discussion below.
&&
.LONG TERM (SUNDAY THROUGH NEXT THURSDAY)...
The large scale longwave pattern commences rather amplified
highlighted by trough over wrn states, ridge over Nrn/Cntrl Rockies
and Wrn Plains, a trough amplifying over Ern states from Canada SWD
to Nrn Gulf states and a nearly zonal flow swd to local area. with
srn stream quite strong, a series of short waves will drop southward
into the wrn trough axis, then weaken as they head rapidly east or
northeast across the eastern U.S. At surface, in the wake of passing
dry cold front, strong 1032mb high builds SEWD from Plains into NE
Gulf region providing a noticeably cooler and drier airmass. A light
freeze is likely inland early Sun and Mon mornings.
Like our previous cold snaps this winter, it will be short lived as
by Sun aftn, the longwave pattern is expected to become more
progressive. Wrn trough amplifies over Desert SW while upstream
ridge moves rapidly ewd with axis over Wrn Gulf region by Sun night
or early Mon. This kicks ern trough into Wrn Atlc. By Mon aftn,
ridge axis has shifted rapidly ewd into extreme Wrn Atlc but
increasingly dampens in response to strong Nrn stream troughing. The
result is semi-zonal flow and progressively moderating temperatures
overspreading NW Gulf region. At surface, ridge of high pressure
will nudge off SE states and into Wrn Atlc. The low level flow veers
allowing more moisture back into local region. Aloft, weak ridging
to zonal flow will persist Tuesday into Thursday. At surface, next
front aided by passing shortwave reaches Wrn Gulf by end of period
and with local area in warm sector, small chance of rain.
Will go with wdly sct-lo sct pops Tues thru Wed, and wdly sct
on Thurs. Otherwise nil pops. With progressive pattern expect sharp
daily temp changes. Good chance of a a light freeze both Sun/Mon
around sunrise with Mins both days at least 10 degrees below climo.
Max temp Sun also around 10 degrees below normal. Then min/max temps
shoot up to around climo Mon/Mon night and around 10 degrees above
climo Tues thru Thur. (Avg inland climo is 41/66 degrees).
&&
.MARINE...
A tight gradient early this morning will continue to support
cautionary level winds away from the immediate coast. The gradient
will weaken through the day allowing winds and seas to subside below
headline criteria for the afternoon. Generally light winds and seas
are then expected through the daylight hours of Friday. A cold front
will cross the forecast waters Friday night followed by cautionary
level northerly flow by Saturday afternoon. Winds and seas are then
expected to further increase to advisory levels Saturday night
through Sunday morning.
&&
.AVIATION (through 00z Fri)...
Unlimited visibility and VFR ceilings will continue through this
evening, except near any large forest fires that may flare up. At
this time, expect winds to remain elevated enough to keep boundary
layer mixed, and prevent significant restrictions due to smoke.
&&
.FIRE WEATHER...
A dry airmass will continue to overspread the region today. Minimum
humidity values are expected to reach the mid to upper 20s across
Georgia and the Florida Big Bend, with lower 30s expected elsewhere.
However, with ERC values as well as winds and dispersions below
critical levels, no red flag warnings are anticipated. Low level
moisture will begin to return on Friday with minimum humidity values
in the lower to mid 30s west of the Apalachicola River rising to the
40s east of the river. The airmass will begin to dry out again on
Saturday in the wake of a dry frontal passage and building high
north of the region. Minimum RH will hover around 35 percent on
Saturday before dropping precipitously into the teens on Sunday, the
next best chance of red flag conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 38 70 45 64 / 0 0 10 30 10
Panama City 65 44 67 46 63 / 0 0 10 30 10
Dothan 61 39 66 41 59 / 0 0 10 20 10
Albany 62 37 67 40 61 / 0 0 10 20 10
Valdosta 65 41 70 44 63 / 0 0 10 30 10
Cross City 70 43 73 47 66 / 0 0 10 40 20
Apalachicola 64 41 66 45 63 / 0 0 10 40 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1145 PM CST WED FEB 8 2012
.DISCUSSION...
ISSUED 851 PM CST WED FEB 8 2012
THE WESTERN AND NORTHERN EDGE OF THE CLOUDS IS BEGINNING TO MAKE
SOME PROGRESS INTO CENTRAL ILLINOIS. HOW SOON THE CLOUDS CLEAR OUT
AND IF THE CLEARING CONTINUES THROUGH MORNING WILL PLAY A MAJOR
ROLL IN LOW TEMPS FOR TONIGHT. SUBSIDENCE INVERSIONS UNDER HIGH
PRESSURE CAN TRAP LOW MOISTURE THAT FORM STRATUS CLOUDS WHICH FILL
IN AGAIN OR RETROGRADE BACK TO THE N-NE. THERE APPEARS TO BE
ENOUGH OF A CLEARING AREA ACROSS N MO/IOWA TO KEEP OUR CLEARING
TRENDS GOING. HAVE TRENDED SLOWER WITH THE CLEARING BASED ON
SATELLITE TRENDS AND THE LATEST HRRR MODEL OUTPUT.
THE SURFACE RIDGE APPEARS TO BE MAINLY SETTLING TO THE SOUTH
INSTEAD OF SLIDING EAST INTO ILLINOIS...SO THAT GIVES MORE
CONFIDENCE TO THE CLEARING SCENARIO. KEPT THE FORECAST LOWS SLIGHTLY
BELOW GUIDANCE...AND WE MAY NOT BE COLD ENOUGH. SURFACE DEWPOINTS
ARE QUITE DRY JUST TO OUR N AND W. WOULD NOT BE SURPRISED TO SEE
SOME MID TEENS REPORTED IN OUR NW COUNTIES IN THE MORNING. FOR
NOW...KEPT UPPER TEENS AND LOW 20S IN PLACE.
NO OTHER CHANGES WERE NEEDED TO THE CURRENT FORECAST/GRIDS.
UPDATED INFO IS ALREADY AVAILABLE.
SHIMON
&&
.AVIATION...
ISSUED 1145 PM CST WED FEB 8 2012...FOR THE 06Z TAFS
CLEARING OF MVFR CLOUDS IS FINALLY MAKING BETTER PROGRESS FROM THE
WEST AND NORTH. PIA AND BMI HAVE BECOME SCT...BUT PIA IS STILL
CLOSE TO A BKN DECK WITH A BAND OF CLOUDS JUST TO THE WEST OF THE
AIRPORT. EVEN WITH THAT...PIA SHOULD BECOME VFR SHORTLY AFTER 07Z
AFTER THOSE CLOUDS SLIDE SE. WILL CLEAR OUT THE REMAINING TAF
SITES BY 08Z-09Z...WITH SOME MVFR FOG POSSIBLE AS TEMPS FALL UNDER
CLEAR SKIES AND LIGHT WINDS. WE KEPT THE TEMPO GOING FM 11Z-14Z
TIME FRAME FOR ALL TERMINALS.
THE MAIN CHANGE TO THE TAFS WAS TO INCREASE VFR CLOUD COVER THUR
AFTERNOON AS WAA FLOWS INCREASE AHEAD OF THE NEXT SYSTEM. SW WINDS
WILL INCREASE TO 10-12KT ON THUR AS WELL.
CLOUDS WILL LIKELY CONTINUE THROUGH THE REMAINDER OF THE TAF
PERIOD...AND POSSIBLY DROP TO MVFR LEVELS AFTER SUNSET ON THURSDAY.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 305 PM CST WED FEB 8 2012
SHORT TERM...TONIGHT THROUGH SATURDAY...
LARGE AREA OF HIGH PRESSURE OVER THE PLAINS WILL MOVE SOUTHEAST AND
DOMINATE THE WEATHER OVER IL TONIGHT THROUGH THURSDAY NIGHT.
EXTENSIVE CLOUD COVER OVER THE AREA WILL MOVE SLOWLY SOUTH WITH MOST
AREAS SEEING CLEAR SKIES BY SUNRISE. THE MAIN WEATHER FEATURE FOR
THE SHORT TERM WILL BE A STRONG COLD FRONT THAT WILL MOVE THROUGH
THE AREA ON FRIDAY. BY MIDDAY...THE FRONT SHOULD BE ABOUT MIDWAY
THROUGH THE FORECAST AREA...THEN INTO THE OHIO VALLEY BY 00Z SAT.
WITH THE CURRENT HIGH PRESSURE HAVING PUSHED MUCH OF THE QUALITY
MOISTURE FAR TO THE SOUTH...IT WILL TAKE SOME TIME FOR IT TO MAKE A
RETURN AND MAY NOT MAKE IT TO CENTRAL IL IN TIME TO INTERACT WITH
THE FRONT. SOME OF THE SHORT RANGE MODELS ARE PAINTING SOME QPF OVER
EASTERN IL WITH THE FRONT...SO WILL CONTINUE WITH SOME SLIGHT CHANCE
POPS THERE. AFTER THAT...THE LARGE CANADIAN AIRMASS IN THE WAKE OF
THE FRONT WILL SPREAD OVER THE CENTRAL/EASTERN CONUS BRINGING
TEMPERATURES BACK TO WINTER-TIME LEVELS STARTING FRIDAY NIGHT AND
LASTING INTO THE EXTENDED PERIOD. FOR NOW...IT APPEARS THAT FRIDAY
NIGHT INTO SATURDAY WILL BE THE COLDEST WITH LOWS 10-20 AND HIGHS IN
THE 20S.
LONG TERM...SUNDAY THROUGH WEDNESDAY...
THE GFS AND ECMWF ARE IN AGREEMENT THAT AN UPPER SHORTWAVE WILL COME
OUT OF THE SOUTHERN ROCKIES AND INTO THE PLAINS EARLY NEXT WEEK. BY
THEN...THE CANADIAN HIGH WILL BE OFF THE EAST COAST AND MOISTURE
FROM THE GULF WILL STREAM NORTHWARD THROUGH THE MS VALLEY. POPS WILL
BEGIN RISING ON MONDAY AS LIGHT SNOW...PERHAPS MIXED WITH LIGHT RAIN
AT THE START...MOVES INTO THE WESTERN HALF OF IL. HIGHEST CHANCE OF
PRECIPITATION WILL BE MONDAY NIGHT WITH THE PASSAGE OF THE UPPER
WAVE. ANY SURFACE REFLECTION OF THIS SYSTEM WILL BE SUBTLE/WEAK AND
THEREFORE THE QPF FORECASTS ARE ON THE LOW SIDE DUE TO THE LACK OF
LOW LEVEL FOCUS.
MODEL AGREEMENT ENDS THERE AS THE NEXT STORM SYSTEM/UPPER LOW COMES
INTO THE SOUTHERN ROCKIES BY TUESDAY. THE GFS SIMPLY KEEPS THE LOW
CHUGGING INTO THE PLAINS AND THROUGH THE MIDWEST ON WEDNESDAY...
WHILE THE ECMWF HOLDS IT BACK WELL TO THE WEST THROUGH THIS PERIOD.
SOME OF THE AUTOMATED POP GUIDANCE IS OBVIOUSLY WEIGHTED TOWARD THE
GFS...WITH LIKELY POPS ON WEDNESDAY. USUALLY...SLOWER IS BETTER WITH
SOUTHWESTERN UPPER LOWS...SO WILL KNOCK DOWN POPS INTO THE CHANCE
RANGE. POPS MAY BE DELAYED EVEN FURTHER IF THE ECMWF ENDS UP BEING
THE WINNING MODEL.
04
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
413 AM EST THU FEB 9 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM
AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
CALM CONDITIONS CAN BE EXPECTED THROUGH TODAY AS HIGH PRESSURE
BUILDS ACROSS CENTRAL INDIANA. SKIES ARE CURRENTLY BEGINNING TO
CLEAR OUT ACROSS THE NORTHWEST QUADRANT OF FORECAST AREA FROM
YESTERDAY/S DISTURBANCE. THIS CLEARING WILL SPREAD FROM NORTHWEST
TO SOUTHEAST OVER THE NEXT SEVERAL HOURS...EVENTUALLY RESULTING IN
CLEAR SKIES ACROSS ENTIRE FORECAST AREA SHORTLY AFTER DAYBREAK.
TEMPS WILL TOP OFF IN THE UPPER 30S/LOW 40S. LEANED TOWARD THE
WARMER NAM DUE TO AMPLE SUNSHINE AND A RETURN TO SOUTHWESTERLY
FLOW. CURRENTLY...TEMPS ACROSS CENTRAL INDIANA ARE RANGING FROM THE
LOW TO MID 20S WHERE CLEARING HAS ALREADY OCCURRED...TO LOW 30S
ACROSS THE SOUTHERN COUNTIES STILL UNDER CLOUD COVER. DEWPOINTS
ARE IN THE LOW 20S AND WINDS ARE LIGHT AND VARIABLE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR THE 090900Z TAF UPDATE/...
EXTREMELY PESKY STRATOCU DECK REMAINS SLOW IN ITS SOUTHWARD
DEPARTURE FROM THE REGION. NEWER RH PROGS OFF THE RUC SUGGESTING
CEILINGS MAY HANG A FEW HOURS LONGER THAN PREVIOUSLY THOUGHT AND
SATELLITE TRENDS WOULD TEND TO SUPPORT THIS IDEA. HAVE THEREFORE
BACKED OFF ON DEPARTURE OF STRATOCU AT KHUF AND KIND UNTIL 12Z AND
POSSIBLY NOT UNTIL 17-18Z AT KBMG. WILL HAVE TO MONITOR TRENDS OVER
THE NEXT FEW HORUS AT KHUF AND KIND AS ENTIRELY PLAUSIBLE THAT THE
STRATOCU TAKES UNTIL MID MORNING BEFORE SHIFTING SOUTH.
06Z DISCUSSION FOLLOWS.
STILL SEEING SOME MVFR CEILINGS AROUND 020 LINGERING IN THE
KIND/KBMG AREAS...BUT THE OVERALL TREND IS FOR THESE CEILINGS TO
DISSIPATE FROM THE NORTHWEST. WILL HOLD ONTO MVFR CEILINGS IN THE
KBMG AREA UNTIL ABOUT 090800Z.
OTHERWISE...BACK EDGE OF VFR CLOUD DECK 035-040 CONTINUES TO SLOWLY
SINK SOUTHEAST. DECK SHOULD CLEAR KIND/KHUF BEFORE SUNRISE...BUT
PROBABLY NOT UNTIL AFTER SUNRISE AT KBMG. THE LATENESS OF THE
CLEARING COUPLED WITH LOWER DEWPOINTS ADVECTING IN FROM THE WEST
SHOULD PREVENT ANY WIDESPREAD OR PROLONGED VISIBILITY RESTRICTIONS
DUE TO FOG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
324 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL MOVE INTO THE AREA BRINGING DRY WEATHER TO
CENTRAL INDIANA THROUGH THURSDAY. AN ARCTIC COLD FRONT WILL MOVE
THROUGH ON FRIDAY BRINGING COLDER THAN AVERAGE TEMPERATURES ALONG
WITH A CHANCE FOR SNOW. ANOTHER FRONT WILL ARRIVE BY MID-WEEK NEXT
WEEK.
&&
.NEAR TERM /OVERNIGHT/...
SATELLITE IMAGES INDICATE CLOUDS OVER CENTRAL INDIANA SLOWLY
CLEARING FROM NORTHWEST TO SOUTHEAST. RUC RH PROFILES SUGGEST
CLOUD SHOULD DEPART TO THE SOUTHEAST AS THE NIGHT
PROGRESSES. THUS MADE SOME MINOR TWEAKS TO SKY GRIDS TO INCREASE
CLEARING GRADIENT...PARTICULARLY ACROSS THE NORTHERN PARTS OF THE
FORECAST AREA.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR PRECIPITATION FRIDAY AND SATURDAY. FOR THE
MOST PART...MODELS ARE SIMILAR ENOUGH THAT A BLEND CAN BE USED.
HIGH PRESSURE WILL PROVIDE DRY CONDITIONS FOR THURSDAY AND
THURSDAY NIGHT UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES.
GENERALLY STUCK WITH MAV MOS...ALTHOUGH WENT A BIT WARMER THAN MAV
MOS SOME AREAS THURSDAY NIGHT WITH AN INCREASE IN CLOUD COVER
EXPECTED.
THE COLD FRONT WILL MOVE INTO THE AREA ON FRIDAY INTO FRIDAY
NIGHT. ALTHOUGH IT WILL NOT HAVE A LOT OF MOISTURE WITH
IT...ARCTIC FRONTS TEND TO BE ABLE TO SQUEEZE OUT MORE THAN
EXPECTED. THUS RAISED MOS POPS FRIDAY AND FRIDAY NIGHT...BUT STUCK
TO NO HIGHER THAN THE CHANCE CATEGORY.
BASED ON EXPECTED BOUNDARY LAYER TEMPERATURES AHEAD OF THE
FRONT...WENT WITH A RAIN/SNOW MIX ACROSS THE SOUTH HALF OF THE
AREA BY FRIDAY AFTERNOON. FOR FRIDAY NIGHT WENT ALL SNOW AS COLDER
AIR MOVES IN.
SOME OF THE LAKE EFFECT SNOW SHOWERS THAT DEVELOP SATURDAY MAY
SNEAK INTO THE NORTHWEST FORECAST AREA...SO WENT SLIGHT CHANCE
POPS THERE. OTHERWISE IT LOOKS LIKE DRY BUT COLD CONDITIONS WILL
BE THE RULE SATURDAY.
WITH CLOUDS AROUND FRIDAY NIGHT...WENT WARMER THAN MAV MOS FOR
LOWS. STUCK WITH A BLEND FOR SATURDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH A 1035-40MB SURFACE HIGH ACROSS THE NORTHERN
PLAINS AND THE FORECAST AREA ON SUBSIDENCE SIDE OF AN UPPER WAVE
ASSOCIATED WITH THE STRONG UPPER LOW JUST EAST OF THE HUDSON BAY IN
QUEBEC. FORTUNATELY OR UNFORTUNATELY...DEPENDING ON WHAT YOU
PREFER...THE BULK OF THE COLDEST AIR WILL BE NORTHEAST OF THE FORECAST
AREA CLOSER TO THE CENTER OF THE UPPER LOW. THE TWO MAIN WEATHER
FEATURES FOR THE EXTENDED TIMEFRAME APPEAR IN DAYS 6/7...AS A COUPLE
UPPER LEVEL WAVES EJECT FROM THE LOWER ROCKIES AND PUSH EAST TOWARD
THE OHIO RIVER VALLEY. MID/LONG RANGE MODEL SOLNS ARE IN FAIRLY GOOD
AGREEMENT WITH THE HANDLING OF THE INITIAL WAVE ON MONDAY NIGHT INTO
TUESDAY AND WITH COLD AIR ALREADY IN PLACE...SNOW IS EXPECTED IN
ALL BUT THE BOTTOM TWO TIER OF COUNTIES WHERE FORECAST SOUNDINGS
ILLUSTRATE A RAIN/SNOW MIX MAY OCCUR. UPPED POPS AREA-WIDE FOR
THIS INITIAL SYSTEM AS MODEL AGREEMENT AND CONSISTENCY HAS BOOST
CONFIDENCE IN ITS OCCURRENCE.
TIMING OF THE SECOND SHORTWAVE IS A LITTLE TRICKIER...AS THE ECMWF
AMPLIFIES UPPER RIDGING AHEAD OF THIS SECOND WAVE MORE THAN THE
GFS. THIS WILL ACT TO SLOW THE SYSTEM A GOOD FULL DAY LATER THAN
THE GFS. WITH MORE MOISTURE TO WORK WITH THAN THE INITIAL
SHORTWAVE...THE TRACK OF THE SURFACE LOW WILL BE IMPORTANT IN
DETERMINING PRECIP TYPE.
&&
.AVIATION /DISCUSSION FOR THE 090900Z TAF UPDATE/...
EXTREMELY PESKY STRATOCU DECK REMAINS SLOW IN ITS SOUTHWARD
DEPARTURE FROM THE REGION. NEWER RH PROGS OFF THE RUC SUGGESTING
CEILINGS MAY HANG A FEW HOURS LONGER THAN PREVIOUSLY THOUGHT AND
SATELLITE TRENDS WOULD TEND TO SUPPORT THIS IDEA. HAVE THEREFORE
BACKED OFF ON DEPARTURE OF STRATOCU AT KHUF AND KIND UNTIL 12Z AND
POSSIBLY NOT UNTIL 17-18Z AT KBMG. WILL HAVE TO MONITOR TRENDS OVER
THE NEXT FEW HORUS AT KHUF AND KIND AS ENTIRELY PLAUSIBLE THAT THE
STRATOCU TAKES UNTIL MID MORNING BEFORE SHIFTING SOUTH.
06Z DISCUSSION FOLLOWS.
STILL SEEING SOME MVFR CEILINGS AROUND 020 LINGERING IN THE
KIND/KBMG AREAS...BUT THE OVERALL TREND IS FOR THESE CEILINGS TO
DISSIPATE FROM THE NORTHWEST. WILL HOLD ONTO MVFR CEILINGS IN THE
KBMG AREA UNTIL ABOUT 090800Z.
OTHERWISE...BACK EDGE OF VFR CLOUD DECK 035-040 CONTINUES TO SLOWLY
SINK SOUTHEAST. DECK SHOULD CLEAR KIND/KHUF BEFORE SUNRISE...BUT
PROBABLY NOT UNTIL AFTER SUNRISE AT KBMG. THE LATENESS OF THE
CLEARING COUPLED WITH LOWER DEWPOINTS ADVECTING IN FROM THE WEST
SHOULD PREVENT ANY WIDESPREAD OR PROLONGED VISIBILITY RESTRICTIONS
DUE TO FOG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...PUMA
SHORT TERM...50
LONG TERM....MRD
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1135 PM EST WED FEB 8 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL MOVE INTO THE AREA BRINGING DRY WEATHER TO
CENTRAL INDIANA THROUGH THURSDAY. AN ARCTIC COLD FRONT WILL MOVE
THROUGH ON FRIDAY BRINGING COLDER THAN AVERAGE TEMPERATURES ALONG
WITH A CHANCE FOR SNOW. ANOTHER FRONT WILL ARRIVE BY MID-WEEK NEXT
WEEK.
&&
.NEAR TERM /OVERNIGHT/...
SATELLITE IMAGES INDICATE CLOUDS OVER CENTRAL INDIANA SLOWLY
CLEARING FROM NORTHWEST TO SOUTHEAST. RUC RH PROFILES SUGGEST
CLOUD SHOULD DEPART TO THE SOUTHEAST AS THE NIGHT
PROGRESSES. THUS MADE SOME MINOR TWEAKS TO SKY GRIDS TO INCREASE
CLEARING GRADIENT...PARTICULARLY ACROSS THE NORTHERN PARTS OF THE
FORECAST AREA.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
FOCUS IS ON CHANCES FOR PRECIPITATION FRIDAY AND SATURDAY. FOR THE
MOST PART...MODELS ARE SIMILAR ENOUGH THAT A BLEND CAN BE USED.
HIGH PRESSURE WILL PROVIDE DRY CONDITIONS FOR THURSDAY AND
THURSDAY NIGHT UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES.
GENERALLY STUCK WITH MAV MOS...ALTHOUGH WENT A BIT WARMER THAN MAV
MOS SOME AREAS THURSDAY NIGHT WITH AN INCREASE IN CLOUD COVER
EXPECTED.
THE COLD FRONT WILL MOVE INTO THE AREA ON FRIDAY INTO FRIDAY
NIGHT. ALTHOUGH IT WILL NOT HAVE A LOT OF MOISTURE WITH
IT...ARCTIC FRONTS TEND TO BE ABLE TO SQUEEZE OUT MORE THAN
EXPECTED. THUS RAISED MOS POPS FRIDAY AND FRIDAY NIGHT...BUT STUCK
TO NO HIGHER THAN THE CHANCE CATEGORY.
BASED ON EXPECTED BOUNDARY LAYER TEMPERATURES AHEAD OF THE
FRONT...WENT WITH A RAIN/SNOW MIX ACROSS THE SOUTH HALF OF THE
AREA BY FRIDAY AFTERNOON. FOR FRIDAY NIGHT WENT ALL SNOW AS COLDER
AIR MOVES IN.
SOME OF THE LAKE EFFECT SNOW SHOWERS THAT DEVELOP SATURDAY MAY
SNEAK INTO THE NORTHWEST FORECAST AREA...SO WENT SLIGHT CHANCE
POPS THERE. OTHERWISE IT LOOKS LIKE DRY BUT COLD CONDITIONS WILL
BE THE RULE SATURDAY.
WITH CLOUDS AROUND FRIDAY NIGHT...WENT WARMER THAN MAV MOS FOR
LOWS. STUCK WITH A BLEND FOR SATURDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
PERIOD BEGINS WITH A 1035-40MB SURFACE HIGH ACROSS THE NORTHERN
PLAINS AND THE FORECAST AREA ON SUBSIDENCE SIDE OF AN UPPER WAVE
ASSOCIATED WITH THE STRONG UPPER LOW JUST EAST OF THE HUDSON BAY IN
QUEBEC. FORTUNATELY OR UNFORTUNATELY...DEPENDING ON WHAT YOU
PREFER...THE BULK OF THE COLDEST AIR WILL BE NORTHEAST OF THE FORECAST
AREA CLOSER TO THE CENTER OF THE UPPER LOW. THE TWO MAIN WEATHER
FEATURES FOR THE EXTENDED TIMEFRAME APPEAR IN DAYS 6/7...AS A COUPLE
UPPER LEVEL WAVES EJECT FROM THE LOWER ROCKIES AND PUSH EAST TOWARD
THE OHIO RIVER VALLEY. MID/LONG RANGE MODEL SOLNS ARE IN FAIRLY GOOD
AGREEMENT WITH THE HANDLING OF THE INITIAL WAVE ON MONDAY NIGHT INTO
TUESDAY AND WITH COLD AIR ALREADY IN PLACE...SNOW IS EXPECTED IN
ALL BUT THE BOTTOM TWO TIER OF COUNTIES WHERE FORECAST SOUNDINGS
ILLUSTRATE A RAIN/SNOW MIX MAY OCCUR. UPPED POPS AREA-WIDE FOR
THIS INITIAL SYSTEM AS MODEL AGREEMENT AND CONSISTENCY HAS BOOST
CONFIDENCE IN ITS OCCURRENCE.
TIMING OF THE SECOND SHORTWAVE IS A LITTLE TRICKIER...AS THE ECMWF
AMPLIFIES UPPER RIDGING AHEAD OF THIS SECOND WAVE MORE THAN THE
GFS. THIS WILL ACT TO SLOW THE SYSTEM A GOOD FULL DAY LATER THAN
THE GFS. WITH MORE MOISTURE TO WORK WITH THAN THE INITIAL
SHORTWAVE...THE TRACK OF THE SURFACE LOW WILL BE IMPORTANT IN
DETERMINING PRECIP TYPE.
&&
.AVIATION /DISCUSSION FOR THE 090600Z TAFS/...
STILL SEEING SOME MVFR CEILINGS AROUND 020 LINGERING IN THE
KIND/KBMG AREAS...BUT THE OVERALL TREND IS FOR THESE CEILINGS TO
DISSIPATE FROM THE NORTHWEST. WILL HOLD ONTO MVFR CEILINGS IN THE
KBMG AREA UNTIL ABOUT 090800Z.
OTHERWISE...BACK EDGE OF VFR CLOUD DECK 035-040 CONTINUES TO SLOWLY
SINK SOUTHEAST. DECK SHOULD CLEAR KIND/KHUF BEFORE SUNRISE...BUT
PROBABLY NOT UNTIL AFTER SUNRISE AT KBMG. THE LATENESS OF THE
CLEARING COUPLED WITH LOWER DEWPOINTS ADVECTING IN FROM THE WEST
SHOULD PREVENT ANY WIDESPREAD OR PROLONGED VISIBILITY RESTRICTIONS
DUE TO FOG.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...PUMA
SHORT TERM...50
LONG TERM....MRD
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1149 PM CST WED FEB 8 2012
.AVIATION...
SFC-925 MB RIDGE AXIS WILL SLIDE ACROSS REGION OVRNGT. SKIES WILL
REMAIN CLEAR WITH LIGHT WINDS 3-6 KTS BACKING TO SW THROUGH 12Z.
PATCHY FOG POSSIBLE FOR A FEW HRS TOWARD DAYBREAK WITH VSBYS
GENERALLY 3-6SM. ATTN THEN SHIFTS TO LARGE AREA OF STRATUS
CURRENTLY MOVING EWD THROUGH NE AND SW IA ATTIM. EXPECT THE
STRATUS TO CONTINUE MOVING EWD INTO MID AM THU AS SFC-925 MB
RIDGE DEPARTS AND WINDS BECOME WESTERLY AT AROUND 15 KTS JUST
ABOVE SFC. 00Z KOAX RAOB SHOWS MOISTURE VERY SHALLOW (ROUGHLY 100
FT THICK CENTERED AROUND AND JUST BELOW 890 MB). CHALLENGE
BECOMES TIMING OF STRATUS INTO THE TERMINALS. SEVERAL FACTORS OR
ELEMENTS MAKE THIS DIFFICULT WITH 1) STRENGTHENING FEB SOLAR
INSOLATION... THAT MAY AID IN SLOWING EWD PROGRESSION... 2)
INCREASED MIXING WITH W/SW WINDS INCREASING 10-15 KTS WITH SOME
GUSTS... WITH POTENTIAL TAP DRY AIR ABOVE THE STRATUS TO ALSO
PROMOTE EROSION. THE SLOWING ALSO DEPICTED IN MOST RECENT RUNS OF
HRRR TOTAL CLOUD COVER PRODUCT... THUS WITH 06Z TAFS HAVE
FOLLOWED SUIT AND PUSHED BACK ARRIVAL OF STRATUS WITH MVFR CIGS
UNTIL AFTN TO EARLY EVE.
&&
.PREV DISCUSSION... /ISSUED 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..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
325 AM CST THU FEB 9 2012
.DISCUSSION...
MAIN FORECAST CHALLENGES CONTINUE TO BE TEMPERATURES UNDER THE COLD
SURGE TONIGHT AND INTO THE WEEKEND AND THE MULTIPLE WAVES OF
PRECIPITATION POSSIBLE LATE IN THE WEEKEND AND MID NEXT WEEK.
SYNOPSIS:
UPPER LEVEL ENERGY IS MOVING EASTWARD ACROSS IOWA WHILE THE NEXT
WAVE TO IMPACT THE REGION IS SETTING UP ACROSS THE INTER-MOUNTAIN
WEST. AT THE SURFACE...HIGH PRESSURE IS SLIDING EASTWARD INTO
IOWA. UNDER THIS HIGH PRESSURE...LOW STRATUS...REMNANT FROM
TUESDAY...CONTINUES TO STICK AROUND ACTING LIKE A BLANKET KEEPING
OVERNIGHT TEMPERATURES WARMER.
TODAY - SATURDAY:
MAIN FORECAST CHALLENGE FOR THE SHORT TERM INVOLVES LINGERING CLOUD
COVER FOR TODAY...AND THE TEMPERATURES ASSOCIATED WITH THE ARCTIC
AIRMASS IN PLACE FRIDAY AND SATURDAY.
LOW LEVEL MOISTURE REMAINS TRAPPED IN A TEMPERATURE INVERSION
UPSTREAM AS FAR AS SOUTHEASTERN COLORADO. WESTERLY/SOUTHWESTERLY
FLOW THURSDAY SHOULD HELP SCOUR OUT SOME OF THOSE CLOUDS...BUT A
WEAK SHORTWAVE CURRENTLY DEVELOPING OVER THE FOUR CORNERS AREA WILL
KEEP SOME ELEVATED CLOUD COVER THROUGHOUT THE DAY. THEREFORE HAVE
KNOCKED THE HIGH TEMPERATURES DOWN A FEW DEGREES FOR TODAY.
POLAR VORTEX OVER HUDSON BAY IS STILL EXPECTED TO EJECT A SHORTWAVE
TROUGH OVER THE GREAT LAKES TO BEGIN THE WEEKEND...WHICH WILL DRAG A
STRONG COLD FRONT SOUTH ACROSS THE AREA STARTING FRIDAY MORNING.
LITTLE MOISTURE WILL ONLY PRODUCE SOME MID TO HIGH LEVEL
CLOUDS...AND GUSTY NORTH-NORTHEAST WINDS WILL FOLLOW THIS FRONT
THROUGH SATURDAY.
ARL
SUNDAY - MONDAY:
THE NEXT IN A SERIES OF UPPER LEVEL WAVES WILL IMPACT THE SOUTHERN
CONUS LATE SUNDAY AND INTO MONDAY. THE MEDIUM RANGE MODELS HAVE
BEEN CONSISTENT OVER THE PAST FEW DAYS SHOWING THIS SYSTEM...BUT
THEY HAVE SLOWED SLIGHTLY FROM EARLIER RUNS. THE GFS CONTINUES TO BE
WARMER THAN THE ECMWF WITH THE SYSTEM. THESE DISCREPANCIES COULD
MEAN A DIFFERENCE BETWEEN RAIN AND SNOW. THE WARMER GFS IS PUSHING
TOWARD THE MAGIC FREEZING LINE WHICH COULD CAUSE A MIXTURE OF
PRECIPITATION...BUT HAVE KEPT THIS FORECAST COOLER THAN THE
GFS...TRENDING TOWARD THE ECMWF. GUIDANCE CONTINUES TO SHOW A LACK
OF A STRONG ENOUGH WARM LAYER TO BRING FREEZING RAIN INTO THE
MIX...AND HAVE KEPT MUCH OF THE PRECIPITATION EVENT SNOW. AS WARM
AIR ADVECTION STREAMS NORTHWARD MONDAY AFTERNOON...EXPECTING A
CHANGE OVER FROM SNOW TO RAIN. IT IS STILL TOO FAR OUT TO DETERMINE
SNOW AMOUNTS AND MODEL VARIATIONS FROM RUN TO RUN ALSO PROHIBIT A
GOOD ESTIMATION...BUT TRENDS OVER THE PAST FEW DAYS SHOW THAT THE
EVENT COULD BRING SNOW ACCUMULATIONS IN THE ADVISORY CATEGORY...WITH
2-5 INCHES POSSIBLE. BETTER ESTIMATIONS WILL BE AVAILABLE AS THE
SYSTEM NEARS. PRECIPITATION WILL EXIT MONDAY EVENING AS THE SYSTEM
MOVES TO THE EAST.
TUESDAY - WEDNESDAY:
A BREAK IN THE ACTIVE WEATHER IS SHORT LIVED AS THE NEXT WAVE MOVES
IN FROM THE SOUTHWEST U.S. TUESDAY NIGHT. THE GUIDANCE HAS SLOWED
WITH THIS SYSTEM AS WELL...AND INTER-OFFICE COLLABORATION WAS TO KEEP
TUESDAY AND TUESDAY NIGHT DRY. EARLY WEDNESDAY MORNING
PRECIPITATION IS EXPECTED TO MOVE NORTHWARD AS THE SYSTEM LIFTS
NORTHEAST OUT OF SOUTHERN NEW MEXICO. AT THIS POINT IN TIME THE
SYSTEM LOOKS TO BE WARM ENOUGH THAT THE MAIN PRECIPITATION TYPE WILL
BE RAIN FOR WEDNESDAY. HOWEVER...DUE TO THIS BEING DAY 7 AND THE
MODEL VARIATIONS CONFIDENCE IN WEDNESDAYS SYSTEM IS LOW.
BILLINGS
&&
.FIRE WEATHER...
FIRE CONDITIONS ARE EXPECTED TO REMAIN LOW THROUGHOUT THE FORECAST
PERIOD. GUSTY NORTH WINDS AND LOW DEWPOINTS FOLLOWING THE COLD
FRONT THIS FRIDAY AND SATURDAY MAY ELEVATE CONDITIONS SLIGHTLY...BUT ALL
GFDI INDEXES REMAIN IN THE LOW CATEGORY.
ARL
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION HAZARD: MVFR STRATUS.
MVFR STRATUS (EXCEPT LOW VFR AT CNU) SHOULD PERSIST OVERNIGHT INTO
THURSDAY MORNING AT LEAST...WITH WEAK ISENTROPIC UPGLIDE PATTERN
IN THE LOW-MID LEVELS. RUC BUFKIT SOUNDINGS SEEM TO HAVE DECENT
HANDLE ON THIS. SOUTHWESTERLY WINDS THURSDAY MAY AIDE IN CLEARING
THE LOW CLOUDS NORTHEASTWARD INTO OUR AREA BY LATE AFTERNOON. MID-HIGH
LEVEL CLOUDS WILL CONTINUE TO BLANKET MUCH OF AREA WITH SHORTWAVE
TROF DROPPING OUT OF THE CENTRAL ROCKIES INTO THE SOUTHERN PLAINS.
THE RAIN/SNOW FROM THIS SHORTWAVE IS EXPECTED TO MISS OUR TAF
SITES TO THE SOUTH IN OKLAHOMA.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 44 25 37 17 / 10 10 0 0
HUTCHINSON 42 24 34 14 / 0 0 0 0
NEWTON 43 24 32 15 / 0 0 0 0
ELDORADO 45 25 35 16 / 0 10 0 0
WINFIELD-KWLD 45 28 40 19 / 10 20 10 0
RUSSELL 39 19 28 11 / 0 0 0 20
GREAT BEND 39 21 30 13 / 10 10 0 20
SALINA 40 22 30 12 / 0 0 0 10
MCPHERSON 42 23 32 13 / 0 0 0 0
COFFEYVILLE 47 33 44 19 / 10 20 10 0
CHANUTE 46 29 39 16 / 0 10 10 0
IOLA 45 28 37 15 / 0 0 10 0
PARSONS-KPPF 46 31 41 18 / 0 20 10 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1140 PM CST WED FEB 8 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN AVIATION HAZARD: MVFR STRATUS.
MVFR STRATUS (EXCEPT LOW VFR AT CNU) SHOULD PERSIST OVERNIGHT INTO
THURSDAY MORNING AT LEAST...WITH WEAK ISENTROPIC UPGLIDE PATTERN
IN THE LOW-MID LEVELS. RUC BUFKIT SOUNDINGS SEEM TO HAVE DECENT
HANDLE ON THIS. SOUTHWESTERLY WINDS THURSDAY MAY AIDE IN CLEARING
THE LOW CLOUDS NORTHEASTWARD INTO OUR AREA BY LATE AFTERNOON. MID-HIGH
LEVEL CLOUDS WILL CONTINUE TO BLANKET MUCH OF AREA WITH SHORTWAVE
TROF DROPPING OUT OF THE CENTRAL ROCKIES INTO THE SOUTHERN PLAINS.
THE RAIN/SNOW FROM THIS SHORTWAVE IS EXPECTED TO MISS OUR TAF
SITES TO THE SOUTH IN OKLAHOMA.
JMC
&&
.PREV DISCUSSION... /ISSUED 543 PM CST WED FEB 8 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MAIN EXPECTED AVIATION HAZARD: MVFR STRATUS.
POLAR SURFACE HIGH WILL REMAIN ACROSS CENTRAL/EASTERN KS OVERNIGHT
BEFORE SHIFTING OFF TO THE EAST ON THURSDAY. ISENTROPIC LIFT
SHOULD SERVE TO KEEP INVERSION IN PLACE OVERNIGHT FROM 850-750 MB.
THEREFORE WILL KEEP MVFR STRATUS IN TACT IN FORECAST OVERNIGHT
WITH ANTICIPATION THAT IT SHOULD DISSIPATE THURSDAY AS LOW-LEVEL
FLOW BECOMES SOUTHWEST-WESTERLY.
JMC
PREV DISCUSSION... /ISSUED 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
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 28 47 25 38 / 0 10 10 0
HUTCHINSON 27 47 24 35 / 0 0 0 0
NEWTON 27 47 24 35 / 0 0 0 0
ELDORADO 28 47 25 37 / 0 0 10 0
WINFIELD-KWLD 29 49 28 41 / 0 10 10 10
RUSSELL 22 40 19 31 / 0 0 0 0
GREAT BEND 24 43 21 33 / 0 10 10 0
SALINA 26 43 22 33 / 0 0 0 0
MCPHERSON 27 46 23 34 / 0 0 0 0
COFFEYVILLE 30 49 33 43 / 0 10 10 10
CHANUTE 29 48 29 39 / 0 0 10 10
IOLA 28 48 28 38 / 0 0 0 10
PARSONS-KPPF 30 49 31 41 / 0 0 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
954 PM MST WED FEB 8 2012
.UPDATE...
841 PM MST WED FEB 8 2012
JUST COMPLETED ANOTHER UPDATE. WAS SKEPTICAL OF EARLIER MODEL DATA
IN REGARDS TO FOG FORMATION SINCE IT OVERDID IT LAST NIGHT.
HOWEVER...SOME FOG HAS DEVELOPED IN THE SOUTHERN PORTION OF THE
FORECAST AREA. THIS DOES MAKE SENSE WITH AREA SOUNDINGS. LATEST
HRRR CATCHES THIS AREA AND EXPANDS IT NORTHEAST AHEAD OF THE
INCOMING SURFACE TROUGH LINE. THIS MAKES SENSE SO HAVE INSERTED
PATCHY FZFG FROM NOW INTO TOMORROW MORNING.
BULLER
&&
.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...
954 PM MST WED FEB 8 2012
FOR THE 06Z TAFS...HIGH PRESSURE WILL MOVE TO THE EAST AS A MID
LEVEL DISTURBANCE AND ASSOCIATED SURFACE TROUGH MOVE INTO THE
AREA THURSDAY. WINDS WILL SWITCH FROM THE SOUTH TONIGHT TO THE
NORTHWEST BY THURSDAY LATE MORNING. STRATUS HAS BEEN SLOWLY MOVING
WESTWARD FROM CENTRAL INTO WESTERN KANSAS AND SOUTHWESTERN NEBRASKA THE
PAST FEW HOURS. WITH SOUTHWEST WINDS CURRENTLY AT KGLD...THINK
STRATUS WILL STAY TO THE EAST. FOR KMCK...CONFIDENCE IS NOT AS
HIGH FOR THE FIRST FEW HOURS UNTIL WIND DIRECTION ESTABLISHES FROM
THE SOUTHWEST. THEREFORE...HAVE INSERTED TEMPO FOR MVFR CIGS FROM
06-08Z. OTHERWISE...CONDS WILL BE VFR AT BOTH LOCATIONS.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
311 AM CST Thu Feb 9 2012
.DISCUSSION...
Widespread stratus once again in place early this morning, which has
held overnight temperatures on the warm side for locations beneath
this cloud deck. Outside of the stratus, temperatures have dropped
quite a bit with lows currently in the teens across northeast Missouri.
Similar to yesterday, believe the stratus will be slow to erode today
which is supported by the latest RUC condensation deficits and
various BUFR soundings. However, overall model performance has been
poor in handling the low level moisture over the past couple of days
so confidence is necessarily high.
Surface ridge will shift into the lower to mid Mississippi valley
today allowing low level winds to swing around to the southwest.
This will advect warmer temperatures into the area although lighter
speeds will prevent significant warming. Mixing to around H9-H85
should help break up clouds to some degree. However, given the
expectation of prolonged, at least broken cloud cover, knocked a few
degrees off of temperatures for this afternoon.
Advertised Hudson Bay low will settle southward through the end of
the week with pronounced short wave energy diving southward into the
central CONUS. Given the meridional nature of the upper height
pattern by the beginning of the weekend in response to amplified
ridging across the western US/Canada, expect a decent chunk of arctic
air to dislodge and plunge southward into the region. Expect the sfc
baroclinic boundary to slide through the area Friday morning with CAA
taking shape thereafter. The main story through the weekend will then
be the cold temperatures as most locations will not see readings
above the freezing mark for several days.
Deep eastern US upper troughing establishes by the middle of the
weekend with upper short wave ridging sliding overhead by Sunday. A
more progressive upper flow pattern then establishes across the
CONUS through the end of the weekend and through the first half of
next week. Models continue to be in good agreement with the timing
of the next progressive short wave trough to affect the area by
Sunday night and Monday. Given the run to run consistency, felt
comfortable continuing to raise POPS for this time period. There
still appears to be a decent shot at accumulating snowfall across
most of the forecast area as this system swings through. The main
limiting factor at this point appears to be the speed at which the
system progresses through the area. Nevertheless, many areas may
finally be in store for the first decent snowfall of the season.
There looks to be a short reprieve on Tuesday before the next system
in the progressive pattern affects the area by Wednesday. Models
have not displayed as good run to run consistency during this period
and will remain close to the consensus numbers to account.
Deroche
&&
.AVIATION...
VFR to maybe high end MVFR ceilings will continue through the
majority of the 06Z TAF cycle as flow begins to return on the
backside of surface high pressure, sloshing upslope stratus back
into the area. Have pushed back clearing to around sunset tomorrow
evening.
Winds will be light east through much of tonight, becoming south
then southwest at around 6-8 knots for most of the day Thursday.
Bookbinder
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
410 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY.
ARCTIC COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY.
COLD SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD SHIFT.
CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF NE KY
WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A GOOD
HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU EARLY
MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER E TO
ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS TO
DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY THRU 06Z FRIDAY...
WIDESPREAD MVFR/LOCAL IFR CONDITIONS IN LIGHT SNOW SHOWERS WILL
CONTINUE THROUGH AT LEAST 09Z ACROSS THE MTNS. HAVE COVERED WITH
TEMPO GROUPS ACROSS KBKW TO HIT IFR CIGS FROM TIME TO TIME.
CLEARING MAKES IT TO NEAR I79 CORRIDOR BY 09Z WITH CENTRAL AND
NORTHERN MTNS TRYING TO SCT OUT BY 12Z. GENERALLY LOW END VFR
LINGERS THRU 15Z ACROSS NE KY...SOUTHERN COALFIELDS...SW VA. THIS
INCLUDES KHTS.
ANY REAMING STRATUS BECOMES MORE SCT-BKN LATE MORNING AND
LINGERING THRU MIDDAY ACROSS NE KY AND WESTERN LOWLANDS. ELSEWHERE
GENERALLY LOOKING AT JUST SOME AFTN CIRRUS.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W
BY 12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLEARING COULD VARY A FEW HRS.
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 THU 02/09/12
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 M M M M H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY M L M M M M M L H H H H
EKN CONSISTENCY M M M M M L L M H H H H
PKB CONSISTENCY M M H H H H H H H H H H
CKB CONSISTENCY L M M H H H H H H H H H
AFTER 06Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
204 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. ARCTIC COLD FRONT BLOWS THROUGH
FRIDAY NIGHT FOR COLDER WIND BLOWN WEEKEND. DRY SUNDAY INTO
MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD SHIFT.
CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF NE KY
WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A GOOD
HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU EARLY
MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER E TO
ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS TO
DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY/...
HIGH PRESSURE OVER THE AREA THU NT EXITS FRI...ALLOWING THE MAIN
EVENT THIS PERIOD...AN ARCTIC COLD FRONT...TO APPROACH FROM THE NW.
AN UPPER LEVEL WAVE IN THE SW FLOW AHEAD OF THE APPROACHING S/W TROF
BRINGS SOME PRECIPITATION AHEAD OF THE SURFACE FRONT LATE FRI INTO
FRI N. UPPER SUPPORT ACTUALLY WEAKENS SOMEWHAT AS THE FRONT ITSELF
CROSSES...LEAVING LOW LEVEL CONVERGENCE AS THE MAIN FORCING.
UPSLOPE FLOW ENSURES BEHIND THE FRONT VERY LATE FRI NT AND CONTINUES
INTO SAT EVENING.
LOWS THU NT WERE CLOSE TO THE WELL CONVERGED NUMBERS AND LOOKED
GOOD. MODELS HINT AT SOME WARM ADVECTION CLOUD AOA H85 AS A WEAK
UPPER LEVEL S/W TROF / COOL POOL MOVES AWAY TO THE NE. EDGED HIGHS
FRI DOWN TOWARD THE LATEST GUIDANCE THOUGH THE ATMOSPHERE SHOULD BE
WELL MIXED IN THE SW FLOW AHEAD OF THE APPROACHING FRONT.
WENT CLOSER TO HIGHER MAV ON LOWS SAT MORNING WHICH WILL BE A
SENSITIVE FUNCTION OF THE TIMING ON THE FRONTAL PASSAGE WHICH SHOULD
BE JUST BEFORE DAWN. BLENDED IN NAM12 TEMPERATURES FOR THE
OVERNIGHT PERIOD TO REFLECT TEMPERATURES HOLDING UP MUCH OF THE
NT...UNTIL THE FRONT PASSES. THIS THEN AFFECTS THE TIMING ON THE
CHANGEOVER TO SNOW AND SNOWFALL AMOUNTS.
HIGHS WERE CLOSE TO CONVERGED GUIDANCE SAT WITH ONLY A SMALL
RECOVERY. GIVEN MIXING...THERE PROBABLY BE A DIURNAL RECOVERY
FOLLOWED BY A QUICK FALL SAT EVENING. LOWS SAT NT ALSO APPEARED
CLOSE TO GUIDANCE AND REASONABLE WITH WIND CHILLS IN THE SINGLE
DIGITS BELOW ZERO OVER THE HIGHER TERRAIN.
HAVE 4 TO 8 INCHES OF FLUFFY SNOW OVER THE HIGHER TERRAIN...SO WILL
ADD ADVISORY TYPE MENTION TO THE HWO.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY THRU 06Z FRIDAY...
WIDESPREAD MVFR/LOCAL IFR CONDITIONS IN LIGHT SNOW SHOWERS WILL
CONTINUE THROUGH AT LEAST 09Z ACROSS THE MTNS. HAVE COVERED WITH
TEMPO GROUPS ACROSS KBKW TO HIT IFR CIGS FROM TIME TO TIME.
CLEARING MAKES IT TO NEAR I79 CORRIDOR BY 09Z WITH CENTRAL AND
NORTHERN MTNS TRYING TO SCT OUT BY 12Z. GENERALLY LOW END VFR
LINGERS THRU 15Z ACROSS NE KY...SOUTHERN COALFIELDS...SW VA. THIS
INCLUDES KHTS.
ANY REAMING STRATUS BECOMES MORE SCT-BKN LATE MORNING AND
LINGERING THRU MIDDAY ACROSS NE KY AND WESTERN LOWLANDS. ELSEWHERE
GENERALLY LOOKING AT JUST SOME AFTN CIRRUS.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W
BY 12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLRING COULD VARY A FEW HRS.
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 THU 02/09/12
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 M M M M H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY M L M M M M M L H H H H
EKN CONSISTENCY M M M M M L L M H H H H
PKB CONSISTENCY M M H H H H H H H H H H
CKB CONSISTENCY L M M H H H H H H H H H
AFTER 06Z FRIDAY...
IFR AGAIN POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...TRM
LONG TERM...MZ/TAX
AVIATION...30
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1056 PM CST WED FEB 8 2012
.DISCUSSION.../ISSUED AT 825 PM CST/
ONLY PROBLEM REMAINS STRATUS ON THE SOUTH END OF FORECAST AREA. IN
LIGHT OF SHORT TERM MODELS WILL CONTINUE TO PLAY IT TO PUSH SLOWLY
EAST AND SLIGHTLY INTO FORECAST AREA INCLUDING YANKTON TO ESPECIALLY
SIOUX CITY. HRRR TRIES TO DEVELOP IT NORTHEAST LATE TO THE AREA FROM
FSD NORTH AND EAST BUT WITH NO SNOW COVER AND ADVANCING DRY AIR AND
SUBSIDENCE...THINK IT WILL STAY OUT OF ALL BUT THE FAR SOUTH. THIS
MODEL TRIED TO DEVELOP SUCH A SEPARATE AREA A FEW NIGHTS AGO WITH
THE LOWER STRATUS AND FOG IN THE DRY AIR TOO FAR NORTH AND THAT
FAILED TO DEVELOP. SO FOR THE AREA EXCEPT THE FAR SOUTH CLEAR SHOULD
CONTINUE. TEMPERATURES LOOK OK WITH THE LIGHT WARMING LOW LEVEL
FLOW PREVENTING A DROP WELL DOWN INTO THE SINGLE DIGITS AS WE HAD
LAST NIGHT. / WILLIAMS
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
06Z TAFS WILL REFLECT MVFR STRATUS MOVING THROUGH KSUX AFTER
MIDNIGHT. A BIT OF STRATUS CONTINUES TO MOVE EASTWARD...EDGING ALONG
OUR FAR SOUTHERN ZONES...AND WILL LIKELY IMPACT KSUX FROM ABOUT
0630Z THROUGH AROUND 1000Z. OTHERWISE CONDITIONS WILL BE VFR UNTIL
THIS EVENING. A STRONG COLD FRONT WILL MOVE SOUTHWARD ACROSS THE FSD
FORECAST AREA LATE THIS AFTERNOON AND EVENING. BEHIND THE FRONTAL
PASSAGE...THE LATEST NAM IS SHOWING MVFR STRATUS TO BE MOVING
SOUTHWARD ALONG WITH THE STRONG COLD AIR ADVECTION. THIS IS
REASONABLE. IT WILL BE CLOSE WHETHER ANY MVFR STRATUS MAKES IT AS
FAR SOUTH AS KSUX BY 06Z/10 HOWEVER. /MJF
&&
.PREV DISCUSSION.../ISSUED AT 316 PM CST/
STRATUS CONTINUES TO NIP AT THE SOUTHERN BORDER OF THE CWA THIS
AFTERNOON AND EXPECT THIS TREND TO CONTINUE THROUGH THE NIGHT. WHILE
THE NORTHERN EDGE IS DISSIPATING...EXPECT THAT A RESURGENCE TO THE
NORTH WILL OCCUR TONIGHT AS THE INVERSION STRENGTHENS AND THE WINDS
REMAIN LIGHT SOUTH TO SOUTHWEST WHICH SHOULD AID IN ADVECTING TO THE
EAST AND NORTHEAST. FOR NOW WILL KEEP NEAR AND ALONG THE MISSOURI
RIVER BUT THIS WILL NEED TO BE WATCHED AS IT COULD CREEP NORTHWARD
AHEAD OF DEVELOPING WEST WINDS FOR THURSDAY. OTHERWISE...DID NOT
CHANGE LOWS TOO MUCH...JUST WARMED A BIT IN THE SOUTH WITH THE
POTENTIAL STRATUS...BUT MAINLY TEENS.
STILL PLANNING ON A MILD AND NOT TOO BREEZY DAY THURSDAY AHEAD OF
THE NEXT COLD FRONT. WEST WINDS SHOULD AVERAGE ABOUT 15 TO 20 MPH.
LOW LEVEL THERMAL FIELD NOT TOO IMPRESSIVE HOWEVER SO WARMEST HIGHS
LIKELY ONLY INTO THE MID 40S...BUT STILL 15 DEGREES OR SO ABOVE
NORMAL. /08
COLD FRONT EXITS THE FORECAST AREA ON THURSDAY NIGHT WITH A SURGE OF
MUCH COLDER AIR ARRIVING LATE AT NIGHT AND INTO FRIDAY. BRISK NORTH
WINDS ARE EXPECTED BEHIND THE FRONT...TURNING NORTHEASTERLY ON
FRIDAY BEFORE GRADUALLY DIMINISHING THROUGH THE DAY. DRY WEATHER
WILL PREVAIL WITH ONLY SOME INCREASED CLOUD COVERAGE FOLLOWING THE
FRONT. LOWS WILL FALL MAINLY INTO THE SINGLE DIGITS FOLLOWED BY
HIGHS ONLY RECOVERING INTO THE LOWER TEENS IN THE NORTHEAST TO NEAR
20 INTO THE MO VALLEY. FRIDAY NIGHT AND SATURDAY WILL PAINT A
SIMILAR PICTURE AS ARCTIC HIGH PRESSURE GRADUALLY SINKS SOUTHWARD
FROM CANADA AND SITS OVERHEAD BY SATURDAY AFTERNOON.
RIDGING BUILDS INTO THE CENTRAL STATES ON SUNDAY WITH THE SURFACE
HIGH SINKING SOUTHEAST OF THE CWA. THE RESULTANT RETURN FLOW WILL
ALLOW SOME WARMING OF THE AIRMASS AND TEMPERATURES TO RETURN TO NEAR
NORMALS IN THE UPPER 20S. A MID LEVEL SHORTWAVE FOLLOWS SUNDAY NIGHT
THROUGH MONDAY WHICH INTRODUCES A CHANCE FOR LIGHT SNOWFALL MAINLY
EAST OF I29. WITH BOTH THE GFS AND ECMWF SHOWING SOME DECENT FORCING
NEAR OUR SOUTHERN AND EASTERN BORDER...WENT AHEAD AND BUMPED UP POPS
ABOUT 10 PERCENT HIGHER THAN THE ALLBLEND.
NEAR SEASONAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR
EARLY NEXT WEEK. MODELS A BIT UNCERTAIN ABOUT A POTENTIAL CUT OFF
LOW WHICH IS NOW TRENDING WELL SOUTH OF THE FORECAST AREA. GIVEN THE
LARGE CHANGE FROM THE PREVIOUS MODEL RUNS...LEFT SOME SLIGHT CHANCE
POPS FROM THE ALLBLEND IN FOR TUESDAY NIGHT AND WEDNESDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1137 PM EST WED FEB 8 2012
.SYNOPSIS...
LOW PRESSURE OFFSHORE THE OUTER BANKS WILL CONTINUE TO MOVE EAST
AND OFFSHORE OVERNIGHT. HIGH PRESSURE BUILDS IN FOR THURSDAY AND
MUCH OF FRIDAY BEFORE AN ARCTIC COLD FRONT CROSSES THE
APPALACHIANS FRIDAY NIGHT INTO SATURDAY BRINGING MOUNTAIN SNOW
SHOWERS ALONG WITH MUCH COLDER AIR. HIGH PRESSURE FOLLOWS THE
FRONT WITH DRIER AIR AND A SLOW MODERATION IN TEMPERATURES FOR
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 830 PM EST WEDENSDAY...
EVENING SOUNDINGS SHOW THE FLOW TURNING MORE UPSLOPISH TONIGHT WITH
RATHER DEEP MOISTURE UNDER THE INVERSION UP TO NEAR 7H. HOWEVER
DESPITE THE COLUMN BEING BELOW FREEZING...MOISTURE ON THE WESTERN
SLOPES HAS BECOME A BIT MORE SHALLOW ALLOWING THE FORMATION OF
MORE FREEZING DRIZZLE AND SNOW GRAINS THIS EVENING. HOWEVER PRECIP
COVERAGE REMAINS RATHER LIMITED GIVEN THE FLOW STILL A BIT TOO
WESTERLY AND BETTER MOISTURE BASICALLY CUT OFF TO THE EAST WITH
THE LOW OFFSHORE. LATEST LOCAL RNK WRF AND RUC ALSO DEPICTS MUCH LESS
UPSLOPE -SHSN COVERAGE AFTER MIDNIGHT WITH THE 85H FLOW TURNING
MORE NORTHERLY. THUS TRIMMED BACK TO LOW CHANCE POPS LATER
TONIGHT MAINLY FAR NW AFTER CURRENT SMALL BANDS FADE THIS EVENING.
ALSO INCLUDING A PERIOD OF SOME LIGHT MIX BASED ON SPOTTER REPORTS
FROM AROUND BLF AND OFF AND ON REPORTING OF UP/-FZRA IN OBS FROM
OUT WEST. WILL ALSO KEEP IN SOME ISOLATED -SHSN MENTION AS FAR
EAST AS THE NEW RIVER VALLEY THRU LATE THIS EVENING BEFORE DRYING
ALOFT WINS OUT. CLOUDS REMAIN SLOW TO GO ACROSS THE SOUTH/EAST AND
WITH MODELS TOO FAST TO ERODE VIA DOWNSLOPE...KEPT LOW CLOUDS IN
FOR A FEW MORE HOURS...WITH A GRADUAL EROSION BACK TO ALONG THE
BLUE RIDGE EXPECTED AFTER MIDNIGHT. BACKED OFF LOWS A LITTLE
ESPCLY WHERE CLOUDS LIKELY TO PERSIST LONGER ON HOLD TEMPS UP SOME
DESPITE WEAK COLD ADVECTION OVERNIGHT. SPS ALSO OUT TO MAKE
MENTION OF ICY SPOTS DUE TO CURRENT LIGHT PRECIP AND OVERNIGHT
BLACK ICE FROM EARLIER MELTING AND REFREEZING.
AS OF 300 PM EST WEDNESDAY...
WITH THIS MORNING`S DISTURBANCE PASSING EAST...MUCH OF THE
SNOW/RAIN IS FINISHED. HOWEVER...WINDS VEER MORE TO THE NW SOMEWHAT
ACROSS SE WEST VA AND ANOTHER SHRTWV APPROACHES FROM IN/IL THIS
EARLY EVENING. SNOW SHOWERS ARE POSSIBLE IN THE LWB/BLF CORRIDOR
WITH THIS WAVE...AND MAY BE SOME FLURRIES INTO THE NEW RIVER
VALLEY AND NW NC. AFTER MIDNIGHT...WINDS DECREASE SUCH THAT ONLY
CLOUDS AND A SNOW SHOWER ACROSS WESTERN GREENBRIER IS EXPECTED.
THE AFOREMENTIONED DISTURBANCE COULD PUT DOWN A FRESH COATING AT
BLF/LWB...AND MAYBE AN INCH OR TWO IN WESTERN GREENBRIER. SNOW MAY
BEGIN TO STICK TO ROADS WITH TEMPS FALLING INTO THE 20S AND ROADS
WHICH ARE NOW WET MAY DEVELOP ICY PATCHES. ALTHOUGH THE GROUND IS
STILL RATHER WARM AND THIS IS NOT GOING TO BE A FLASH FREEZE.
WINDS MAY GUST TO 30 MPH EARLY TONIGHT IN NW NC. OVERCAST WILL
HOLD ALONG THE HIGHLANDS OF SE WEST VA THURSDAY...THEN CLEAR BY
LATE MORNING WITH PLENTY OF SUNSHINE AND HIGHS IN THE LOW TO UPPER
40S...A FEW DEGREES BELOW GUIDANCE.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 230 PM EST WEDNESDAY...
HIGH PRESSURE CONTINUES TO MOVE EAST THURSDAY NIGHT INTO FRIDAY.
FLOW AROUND THE HIGH WILL RESULT IN WESTERLY WINDS FOR OUR REGION.
LOW TEMPERATURES THURSDAY NIGHT WILL BE NEAR NORMAL WITH READINGS
FROM THE UPPER TEENS IN THE NORTHWEST MOUNTAINS TO THE UPPER 20S IN
THE PIEDMONTS.
MOISTURE INCREASES ON FRIDAY IN ADVANCE OF AN APPROACHING COLD
FRONT. PLAYED HIGHS ON FRIDAY CLOSE TO ADJMETBC WITH READINGS
FROM THE MID 30S IN THE NORTHWEST MOUNTAINS TO THE MID 50S IN THE
SOUTHEAST. THE COLD FRONT WILL MOVE ACROSS THE AREA FRIDAY NIGHT
BRINGING SCATTERED RAIN/SNOW SHOWERS TO THE MOUNTAINS...WITH MAINLY
SPRINKLES/FLURRIES EAST OF THE BLUE RIDGE. SNOWFALL AMOUNTS WILL
GENERALLY BE LESS THAN AN INCH OR TWO. THE HIGHEST SNOW AMOUNTS WILL
FALL IN WESTERN GREENBRIER COUNTY. LOW TEMPERATURES FRIDAY NIGHT
WILL RANGE FROM THE UPPER TEENS IN THE NORTHWEST MOUNTAINS TO THE
MID 30S IN SOUTHSIDE.
ON SATURDAY...PREVAILING NORTHWEST FLOW WILL HELP MAINTAIN SNOW
SHOWERS AND SNOW FLURRIES ACROSS THE MOUNTAINS. ADDITIONAL SNOWFALL
AMOUNTS UP TO AN INCH ARE POSSIBLE. 85H WINDS ON THE GFS AND ECMWF
ARE PROGGED TO BE IN THE 35 TO 40 KT RANGES ACROSS THE WEST. WE MAY
SEE SOME SURFACE GUSTS UP TO 35 MPH AT HIGHER ELEVATIONS. THE
PRESSURE RISES ON THE ECMWF ARE NOTEWORTHY. WINDS SHOULD REMAIN
BELOW ADVISORY LEVELS ACROSS THE HIGHEST ELEVATIONS. COLD AND
WINDY ON SATURDAY WITH HIGHS FROM THE MID 20S IN THE WEST TO MID 40S
IN THE EAST. THE SNOW SHOWERS AND SNOW FLURRIES WILL GRADUALLY
DECREASE IN COVERAGE AND END SATURDAY AFTERNOON INTO SATURDAY NIGHT.
LOWERED MINIMUM TEMPERATURES FOR SATURDAY NIGHT FROM THE SINGLE
DIGITS TO THE LOWER 20S IN THE SOUTHEAST. WIND CHILLS BELOW ZERO ARE
POSSIBLE IN THE HIGHEST ELEVATIONS OF THE NORTHWEST MOUNTAINS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 237 PM EST WEDNESDAY...
AFTER A BREEZY SUNDAY MORNING...COLD HIGH PRESSURE WILL BUILD INTO
THE REGION. THIS RIDGE SLIDES OFF THE MID ATLANTIC COAST MONDAY
NIGHT. A FEW SHOWERS MAY ACCOMPANY A WARM FRONT ON TUESDAY. A COLD
FRONT APPROACHES FROM THE WEST ON WEDNESDAY TO INCREASE SHOWERS
CHANCES.
TEMPERATURES SUNDAY WILL BE BLUSTERY AND 10F-15F BELOW NORMAL.
TEMPERATURES MODERATE TOWARD SEASONAL LEVELS ON MONDAY. THE PASSING
OF THE WARM FRONT TUESDAY WILL ALLOW TEMPERATURES TO WARM INTO THE
UPPER 40S TO LOWER 50S. BEING AHEAD OF A COLD FRONT
WEDNESDAY...TEMPERATURES COULD JUMP 10-15F ABOVE NORMAL.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
AS OF 1115 PM EST WEDNESDAY...
SCATTERED VERY LIGHT SNOW SHOWERS AND/OR FREEZING DRIZZLE WILL
CONTINUE AT TIMES ACROSS THE UPSLOPE AREAS OF SE WVA INTO THE
EARLY MORNING HOURS BUT REMAIN PRIMARILY WEST OF THE TAF SITES.
THE UPSLOPE NW FLOW WILL RESULT IN PERSISTENT MVFR/IFR CIGS AT
KBLF/KLWB OVERNIGHT INTO EARLY THU...AND PERIODIC MVFR AT KBCB
WITH MAINLY VFR CIGS FROM KROA AND POINTS EAST OVERNIGHT UNTIL
CLOUDS FADE LATE. AN INTERMITTENT VSBY REDUCTION REMAINS POSSIBLE
AROUND KBLF OVERNIGHT IN -SHSN BANDS BUT TOO IFFY TO INCLUDE AT
THIS POINT SO KEEPING VFR VSBYS. MAY ALSO SEE SOME PATCHY FOG
DEVELOP OUT EAST AS SKIES CLEAR AND WINDS LIGHTEN SOME BUT ALSO
LOW CONFIDENCE SO ONLY INCLUDING A MENTION AT KLYH. NW WINDS WILL
REMAIN GUSTY FOR A FEW MORE HOURS OVERNIGHT BUT THEN START TO
DIMINISH WELL BEFORE DAYBREAK THURSDAY AS HIGH PRESSURE BUILDS IN.
ANY FLURRIES END THURSDAY MORNING AT KBLF/KLWB...WITH CIGS BECOMING
BKN AND RISING ABV 3KFT PERHAPS BY MID MORNING. OTRW SHOULD RETURN
TO WIDESPREAD VFR THURSDAY AFTERNOON INTO FRIDAY...BEFORE AN
ARCTIC COLD FRONT PRODUCES SNOW SHOWERS AND BRINGS MVFR/IFR
RESTRICTIONS TO KLWB/KBLF FRIDAY NIGHT THROUGH LATE SAT. A PERIOD
OF MVFR CIGS AND VSBYS ALSO POSSIBLE LATER FRIDAY NIGHT AT KBCB
AND POSSIBLY KROA WITH VFR CIGS OUT EAST. HIGH PRESSURE AND VFR
RETURNS SUNDAY AND MONDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/KM
NEAR TERM...JH/KM
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/JH/KM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
250 AM CST THU FEB 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
250 AM CST THU FEB 9 2012
MAIN FORECAST CONCERNS ARE ON LIGHT SNOW/FLURRY CHANCES TONIGHT
THROUGH FRIDAY AND HIGH TEMPERATURES FRIDAY INTO SATURDAY BEHIND
THE ARCTIC COLD FRONT.
CURRENT SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
CENTRAL ONTARIO WEST THROUGH SOUTHERN MANITOBA INTO SOUTHERN
SASKATCHEWAN. THE FRONT WAS MOVING SOUTH EARLY THIS MORNING. AN
AREA OF STRATUS WAS NOTED ACROSS EASTERN NEBRASKA/SOUTHWEST
IOWA...MOVING EAST AND SLIGHTLY NORTHEAST. WILL HAVE TO KEEP A
CLOSE WATCH ON THIS AREA OF STRATUS AS SOUTHWEST WINDS INCREASE
AHEAD OF THE FRONT THIS MORNING INTO THIS AFTERNOON WITH THE
POSSIBILITY OF THE STRATUS ADVECTING INTO THE FORECAST AREA.
HIGH PRESSURE WILL SLIDE SOUTH OF THE REGION TODAY AS THE ARCTIC
COLD FRONT APPROACHES THE REGION. THE HRRR DEVELOPS AN AREA OF
STRATUS ACROSS SOUTHWEST/SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA
LATE THIS MORNING...WITH THE STRATUS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS AFTERNOON. FORECAST SOUNDINGS ACROSS
SOUTH CENTRAL MINNESOTA AND NORTHEAST IOWA SHOW VERY DRY AIR IN
THE LOWER LEVELS OF THE ATMOSPHERE LATE THIS MORNING INTO THIS
AFTERNOON. SURFACE DEWPOINTS ACROSS THIS AREA ARE ONLY IN THE
SINGLE DIGITS TO LOWER TEENS WITH THE ONLY APPRECIABLE LOW LEVEL
MOISTURE NOTED IN THE AREA OF STRATUS ACROSS EASTERN NEBRASKA INTO
SOUTHWEST IOWA. PLAN ON MOSTLY SUNNY SKIES THROUGH EARLY AFTERNOON
WITH CLOUDS INCREASING DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS AS THE COLD FRONT MOVES INTO THE FORECAST AREA. THE FRONT IS
EXPECTED TO BE POSITIONED FROM WESTERN LAKE SUPERIOR INTO
SOUTHWEST MINNESOTA BY 6 PM THIS EVENING. LOOK FOR THE FRONT TO
SWEEP ACROSS THE AREA DURING THE EVENING HOURS. THE BEST FORCING
FOR PRECIPITATION APPEARS TO BE RIGHT ALONG AND SLIGHTLY TRAILING
THE COLD FRONT. WOULD EXPECT TO SEE A FEW FLURRIES OR LIGHT SNOW
SHOWERS THIS EVENING INTO THE OVERNIGHT HOURS AS THE FRONT MOVES
THROUGH. NAM FORECAST SOUNDINGS SHOW THE POTENTIAL FOR SNOW
SHOWERS...MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. THE GFS
SHOWS A BRIEF WINDOW OF FLURRIES/LIGHT SNOW SHOWERS THIS EVENING
BEFORE DRY/COLD AIR MOVES IN. A BRIEF SHOT OF ISENTROPIC LIFT
NOTED IN THE LATEST NAM SOLUTION ON THE 270 THROUGH 280 K SURFACES
THIS EVENING WITH CONDENSATION PRESSURE DEFICITS LOWERING TO
AROUND 7 MB WITHIN THIS LAYER. IF LIGHT SNOW DEVELOPS...LITTLE OR
NO ACCUMULATION IS EXPECTED WITH THIS ACTIVITY. WILL INCLUDE A
SLIGHT CHANCE OF VERY LIGHT SNOW ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN.
SLIGHTLY HIGHER CHANCES FOR SNOW ACROSS NORTH CENTRAL WISCONSIN.
OTHERWISE...PLAN ON MOSTLY CLOUDY SKIES OVERNIGHT WITH LOW
TEMPERATURES RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE UPPER TEENS ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
AN UPPER LEVEL TROUGH IS EXPECTED TO PUSH INTO THE AREA ON
FRIDAY...WITH PV15 SURFACES DIPPING TO 540 MB AS IT MOVES IN. THE
COLDEST AIR ALOFT WILL FILTER IN BEHIND THIS WAVE WITH 900 MB
TEMPERATURES FALLING TO -17C BY FRIDAY AFTERNOON. A RATHER NICE PV
ADVECTION SIGNAL MOVING ACROSS THE FORECAST AREA FRIDAY
MORNING...WITH PV ADVECTION IN THE 500-300 MB LAYER OF AROUND 37
PVU/S. EVEN WITH THIS UPPER LEVEL FORCING...THE LOWER LEVEL ARE
VERY DRY LIMITING OVERALL SNOW CHANCES AS THE WAVE MOVES
THROUGH...WITH LITTLE OR NO CONTRIBUTION FROM FORCING ALOFT.
HOWEVER...GIVEN THE COLD AIR AT 900 MB PRODUCING STEEP LAPSE
RATES...CANNOT RULE OUT A FEW CONVECTIVE SNOW SHOWERS. HAVE
LOWERED PRECIPITATION CHANCES SLIGHTLY. WILL MAINTAIN A SLIGHT
CHANCE OF SNOW SHOWERS THROUGH THE DAY ON FRIDAY EAST OF THE
MISSISSIPPI RIVER. OCCASIONAL FLURRIES CAN BE EXPECTED ACROSS THE
ENTIRE FORECAST AREA. LOOK FOR HIGH TEMPERATURES TO RANGE FROM THE
TEENS ACROSS NORTHERN WISCONSIN TO AROUND 20 ACROSS FAR SOUTHWEST
WISCONSIN. COLD SURFACE HIGH PRESSURE IS EXPECTED TO BUILD INTO
THE FORECAST AREA FRIDAY NIGHT...WITH THE CENTER OF THE HIGH
POSITIONED OVER THE DAKOTAS. LOOK FOR CLOUDS TO GRADUALLY DECREASE
FROM NORTH TO SOUTH LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING
AS DRIER LOW LEVEL AIR ADVECTS IN AND ERODES ANY LINGERING
STRATUS. LOW TEMPERATURES FRIDAY NIGHT WILL BE ON THE CHILLY
SIDE...WITH LOWS RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE SINGLE DIGITS ABOVE ZERO ACROSS
NORTHEAST IOWA.
LOW PRESSURE WILL DROP SOUTH ACROSS JAMES BAY INTO CENTRAL QUEBEC ON
SATURDAY. MEANWHILE...COLD HIGH PRESSURE IS EXPECTED TO BE CENTERED
OVER THE DAKOTAS. THIS WILL PRODUCE A TIGHT PRESSURE GRADIENT ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY WITH WEST WINDS INCREASING INTO
THE 10 TO 18 MPH RANGE. HIGHS ON SATURDAY WILL BE MAINLY IN THE
TEENS TO AROUND 20 ACROSS NORTHEAST IOWA INTO FAR SOUTHERN
WISCONSIN. PLAN ON WIND CHILLS IN THE SINGLE DIGITS ABOVE TO
SINGLE DIGITS BELOW ZERO ON SATURDAY. LOOK FOR ONE MORE CHILLY
NIGHT SATURDAY NIGHT WITH LOWS DROPPING INTO SINGLE DIGITS. WEST
WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT AS THE RIDGE AXIS
MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
250 AM CST THU FEB 9 2012
09.00 MEDIUM RANGE MODELS IN AGREEMENT ON SUNDAY SHOWING AN UPPER
RIDGE ACROSS THE FORECAST AREA WITH A TROUGH DIVING INTO THE
SOUTHWEST CONUS. WARMER TEMPERATURES ARE ON TAP FOR SUNDAY AS 850
MB TEMPS WARM TO AROUND -4 C BY SUNDAY AFTERNOON. PLAN ON MOSTLY
SUNNY SKIES ON SUNDAY WITH HIGH TEMPERATURES IN THE 20S. THE TROUGH
WILL EJECT INTO THE CENTRAL/NORTHERN PLAINS LATE SUNDAY NIGHT AND
MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY ON MONDAY. THIS SYSTEM
IS EXPECTED TO BRING LIGHT SNOW TO THE FORECAST AREA...WITH LIGHT
ACCUMULATIONS POSSIBLE. LATEST GUIDANCE SUGGEST 1 TO 3 INCHES OF
ACCUMULATION. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW MODEL
RUNS. IF TRENDS CONTINUE...SNOW CHANCES WILL LIKELY BE INCREASED
SIGNIFICANTLY. GOOD MODEL AGREEMENT TUESDAY INTO WEDNESDAY SHOWING
ZONAL FLOW ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MODELS MUCH
DRIER THIS RUN ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WITH QUIET ZONAL FLOW ACROSS THE REGION. HAVE DECIDED
TO REMOVE PRECIPITATION CHANCES THROUGH THIS PERIOD. LOOK FOR HIGH
TEMPERATURES IN THE LOW TO MID 30S TUESDAY INTO WEDNESDAY...WITH
OVERNIGHT LOWS IN THE 20S.
&&
.AVIATION...
1025 PM CST WED FEB 8 2012
HIGH PRESSURE SETTLING TO THE SOUTH ACROSS IOWA/MISSOURI WILL ALLOW
SURFACE WINDS AT BOTH TAF SITES TO TURN TO THE SOUTHWEST. DURING THE
DAYTIME...A TIGHTENING PRESSURE GRADIENT AHEAD OF AN APPROACHING
ARCTIC COLD FRONT WILL PROMOTE GUSTY WINDS...PARTICULARLY AT KRST.
ONE THING TO NOTE...CURRENTLY WATCHING AREA OF MVFR STRATUS ACROSS
EASTERN NEBRASKA / WESTERN IOWA. RECENT FORECAST GUIDANCE TRIES TO
SWING THIS TOWARDS NORTHERN IOWA / SOUTHERN MINNESOTA BY THURSDAY
MORNING. CONFIDENCE IS LOW ON THIS SCENARIO AT THIS TIME GIVEN DRIER
AIR AND THINKING DAYTIME MIXING WILL HELP TO ERODE THESE CLOUDS.
HOWEVER...SOMETHING TO WATCH CLOSELY THROUGH THE OVERNIGHT.
TOWARDS THE END OF THE FORECAST PERIOD...THE ARCTIC FRONT SHOULD BE
NEARING OR CROSSING BOTH TAF SITES...BRINGING NORTHERLY WINDS AND
MOSTLY MID TO HIGH LEVEL CLOUDS. SEE THE POTENTIAL FOR MVFR CIGS
AFTER 06Z HOWEVER...AND THIS MAY NEED TO ADDED TO LATER FORECASTS.
THE BEST FORCING FOR ANY SNOW SHOWERS WILL REMAIN NORTHEAST OF THE
TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 AM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....TAYLOR
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1007 PM MST WED FEB 8 2012
.AVIATION...06Z TAFS
VFR CONDITIONS EXPECTED AT ALL LOCATIONS EXCEPT RAWLINS. THEY ARE
LOOKING AT MVFR CONDITIONS THROUGH THE MORNING HOURS BEFORE CLOUDS
BREAK AFTER 09Z. VFR CONDITIONS AFTERWARDS.
CLAYCOMB
&&
PREV DISCUSSION... /ISSUED 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 SLOWER 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.
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 GRAND JUNCTION CO
814 AM MST THU FEB 9 2012
.UPDATE...
BASED ON LOCAL OBSERVATIONS AND WEB CAMS DECIDED TO EXTEND THE
DENSE FOG ADVISORY UNTIL 0900. THE FOG SEEMED ESPECIALLY DENSE
ALONG THE I-70 CORRIDOR WHICH IS A BIG IMPACT.
&&
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
EXPECT WIDESPREAD MVFR CIGS AND VSBY ALONG A KRKS-30W KGJT-35NW KCEZ-
30SW KPSO AS A FAST MOVING SHORTWAVE TROUGH CONTINUES TO IMPACT MUCH
OF COLORADO EARLY THIS MORNING. RESIDUAL LOW-LEVEL MOISTURE AND
CLEARING SKIES ON THE BACK SIDE OF THIS SYSTEM WILL RESULT IN AREAS
OF FOG ACROSS THE CENTRAL COLORADO VALLEYS INCLUDING KGJT...KRIL...
KMTJ AND KASE. PERIODS OF IFR/LIFR CONDITIONS ARE LIKELY AT TIMES.
MEANWHILE...LINGERING SNOW IN THE COLORADO MOUNTAINS WILL BRING
WIDESPREAD MOUNTAIN OBSCURATIONS THROUGH MIDDAY. CONDITIONS IMPROVE
FROM WEST TO EAST DURING THE AFTERNOON. MOUNTAINS SNOW WILL BECOME
SHOWERY AND SCATTERED IN COVERAGE. MEANWHILE...EXPECT VFR
CONDITIONS ACROSS ALL OF EASTERN UTAH AND THE SOUTHWEST CORNER OF
COLORADO TODAY.
SHOWERS DIMINISH SHORTLY AFTER SUNSET AND VFR CONDITIONS WILL BECOME
THE RULE OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...DENSE FOG ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 006.
WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 018.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
436 AM MST THU FEB 9 2012
.SHORT TERM /TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
EXPECT WIDESPREAD MVFR CIGS AND VSBY ALONG A KRKS-30W KGJT-35NW KCEZ-
30SW KPSO AS A FAST MOVING SHORTWAVE TROUGH CONTINUES TO IMPACT MUCH
OF COLORADO EARLY THIS MORNING. RESIDUAL LOW-LEVEL MOISTURE AND
CLEARING SKIES ON THE BACK SIDE OF THIS SYSTEM WILL RESULT IN AREAS
OF FOG ACROSS THE CENTRAL COLORADO VALLEYS INCLUDING KGJT...KRIL...
KMTJ AND KASE. PERIODS OF IFR/LIFR CONDITIONS ARE LIKELY AT TIMES.
MEANWHILE...LINGERING SNOW IN THE COLORADO MOUNTAINS WILL BRING
WIDESPREAD MOUNTAIN OBSCURATIONS THROUGH MIDDAY. CONDITIONS IMPROVE
FROM WEST TO EAST DURING THE AFTERNOON. MOUNTAINS SNOW WILL BECOME
SHOWERY AND SCATTERED IN COVERAGE. MEANWHILE...EXPECT VFR
CONDITIONS ACROSS ALL OF EASTERN UTAH AND THE SOUTHWEST CORNER OF
COLORADO TODAY.
SHOWERS DIMINISH SHORTLY AFTER SUNSET AND VFR CONDITIONS WILL BECOME
THE RULE OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...DENSE FOG ADVISORY UNTIL 8 AM MST THIS MORNING FOR ZONE 006.
WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR ZONE 018.
UT...NONE.
&&
$$
SHORT TERM...15
LONG TERM....NL
AVIATION.....NL
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION SECTION
NWS TALLAHASSEE FL
530 AM EST Thu Feb 9 2012
.SYNOPSIS...
07Z water vapor and H4 RUC analysis shows an upper level pattern
along the northern Gulf coast dominated by southern stream flow.
Main belt of westerlies lies to our north helping to keep our
weather quiet...at least for today. Similar to the past several
days, WV imagery suggest we will continue to see periods of high
level cirrus streaming overhead to filter the sunshine. Looking
upstream, we see shortwave energy diving southeast across the
inter-mountain west toward the Southern Plains. It will be this
energy that will bring our next potential for showers Friday night
as it ejects quickly eastward and over our region.
At the surface,
1030mb high pressure is centered along the middle MS Valley this
morning. Our position well to its southeast results in a decent
gradient across the area, and is providing steady northerly breezes.
In response to the wind, our temperatures are a bit warmer than
previously expected. In fact, some spots that had dropped into the
middle 40s earlier, have rebounded several degrees in response to
the low level mixing.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
Today,
Dry and seasonably pleasant weather. Surface ridge will build south
through the day allowing the gradient to weaken. Our skies will
feature filtered sunshine as upper level moisture continues to
stream overhead in the form of cirrus. Less efficient mixing should
generally keep high temperatures a few degrees cooler than what was
experience Wednesday. Current grids show mid-afternoon temps
reaching the lower 60s north and middle to upper 60s south. Far
southeast portions of the Big Bend/Suwannee River Valley will make a
run at the lower 70s.
Tonight,
With the surface ridge center in closer proximity, will see a better
chance for low temps to fall into the middle to upper 30s late. Best
chances to reach these numbers will be west of the Suwannee River
Valley/I-75 corridor. Developing light easterly flow associated with
an organizing surface trough along the FL East Coast is expected to
transport a slight increase in Atlantic moisture into these far
eastern zones, and keep low temps in the lower/middle 40s. Current
numbers suggest only a minimal frost threat.
Friday,
Daylight hours of Friday will feature generally dry conditions with
increasing clouds. GFS has come around to support the earlier
solution of the ECMWF/CMC of a more well-defined mid-level shortwave
approaching from the west. As it appears now, deep layer synoptic
support/QG-forcing associated with this energy, along with the best
upper level jet configuration will not arrive until Friday
evening/night, and will keep shower chances out of the forecast.
Despite the increasing clouds, at least some filtered sunshine and a
weak thermal ridge ahead of the approaching system should allow
temperatures to rebound into the mid/upper 60s for most areas, and
upper 60s/lower 70s for the FL Big Bend.
Friday Night,
Shortwave trough will pivot across the area accompanied by an
impressive 150+kt jetstreak. Global guidance members are in good
agreement showing the best deep layer lift combination of QG forcing
and jet dynamics will come together over the southern half of the
area...and especially offshore. Current grids will show slight
chance 20% PoPs north, and chance 30-50% Pops south of a line
roughly from Panama City to Tallahassee and Valdosta. Rainfall
amounts look to be on the light side, from maybe a few hundredths of
an inch north, to potentially a couple tenths over the coastal
waters and SE Big Bend zones. System will be quite progressive and
expect best lift and moisture to be quickly exiting to our east
toward sunrise.
Saturday,
Clearing skies and a much cooler/drier airmass will be arriving on
NW winds in the wake of Friday Night`s system. Been a while since we
saw 850mb temps down to zero overhead, but ECMWF/GFS both show the
850 zero line arriving by the end of the day. Although the daylight
hours of Saturday will still see temps reaching the low/mid 60s,
Saturday Night and Sunday Nights will feature some rather chilly
readings, and light freeze potential. More details in the long term
discussion below.
&&
.LONG TERM [Saturday night through next Thursday]...The large scale
longwave pattern commences rather amplified highlighted by trough
over wrn states, ridge over Nrn/Cntrl Rockies and Wrn Plains, a
trough amplifying over Ern states from Canada SWD to Nrn Gulf states
and a nearly zonal flow swd to local area. with srn stream quite
strong, a series of short waves will drop southward into the wrn
trough axis, then weaken as they head rapidly east or northeast
across the eastern U.S. At surface, in the wake of passing dry cold
front, strong 1032mb high builds SEWD from Plains providing a
noticeably colder and drier airmass. A light advective freeze is
likely inland early Sun and Mon mornings but on first morning this
will be contingent on wind speeds assocd with high which will still
be in the Lwr Ms Valley and doesnt favor ideal radiational cooling.
Winds however, will make it feel colder and expect bone dry RH will
favor fire wx hazards. By sunrise Monday, high will be almost
overhead with much lighter winds and better chance for nearly ideal
radiational cooling, and cant totally discount a hard freeze for
some areas.
Like our previous cold snaps this winter, it will be short lived as
by Sun aftn, the longwave pattern is expected to become more
progressive. Wrn trough amplifies over Desert SW while upstream
ridge moves rapidly ewd with axis over Wrn Gulf region by Sun night
or early Mon. This kicks ern trough into Wrn Atlc. By Mon aftn,
ridge axis has shifted rapidly ewd into extreme Wrn Atlc but
increasingly dampens in response to strong Nrn stream troughing. The
result is semi-zonal flow and the start of progressively moderating
temperatures overspreading NW Gulf region. At surface, ridge of high
pressure will nudge off SE states and into Wrn Atlc. The low level
flow veers allowing more moisture back into local region. Aloft,
weak ridging to zonal flow will persist Tuesday into Thursday. At
surface, next front aided by passing shortwave reaches Wrn Gulf by
end of period and with local area in warm sector, small chance of
rain per slower GFS. If EURO verifies, front could reach area on
Wed. With model discrepancies this far out, took a blend for my
timing and pop numbers.
Will go with wdly sct-lo sct pops Tues thru Wed, and wdly sct
on Thurs. Otherwise nil pops. With progressive pattern expect sharp
daily temp changes. Good chance of a a light freeze both sun/Mon
around sunrise with Mins both at least 10 degrees below climo. Max
temp Sun also around 10 degrees below normal. Then min/max temps
shoot up to around climo Mon/Mon night and around 10 degrees above
climo Tues thru Thur. (Avg inland climo is 41/66 degrees).
&&
.AVIATION [through 12z Fri]...
Unlimited visibility and VFR ceilings will continue through this
evening, except near any large forest fires that may flare up. At
this time, expect winds to remain elevated enough to keep boundary
layer mixed, and prevent significant restrictions due to smoke.
Small chance of Mvfr/borderline IFR CIGS and patchy fog near sunrise
Fri mainly GA terminals and at TLH. Will insert tempo groups here to
account for same.
&&
.MARINE...
A tight gradient early this morning will continue to support
cautionary level winds away from the immediate coast. The gradient
will weaken through the day allowing winds and seas to subside below
headline criteria for the afternoon. Generally light winds and seas
are then expected through the daylight hours of Friday. A cold front
will cross the forecast waters Friday night followed by cautionary
level northerly flow by Saturday afternoon. Winds and seas are then
expected to further increase to advisory levels Saturday night
through Sunday morning.
&&
.FIRE WEATHER...
A dry airmass will continue to overspread the region today. Minimum
humidity values are expected to reach the mid to upper 20s across
Georgia and the Florida Big Bend, with lower 30s expected elsewhere.
However, with ERC values as well as winds and dispersions below
critical levels, no red flag warnings are anticipated. Low level
moisture will begin to return on Friday with minimum humidity values
in the lower to mid 30s west of the Apalachicola River rising to the
40s east of the river. The airmass will begin to dry out again on
Saturday in the wake of a dry frontal passage and building high
north of the region. Minimum RH will hover around 35 percent on
Saturday before dropping precipitously into the teens on Sunday, the
next best chance of red flag conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 38 70 45 64 / 0 0 10 30 10
Panama City 65 44 67 46 63 / 0 0 10 30 10
Dothan 61 39 66 41 59 / 0 0 10 20 10
Albany 62 37 67 40 61 / 0 0 10 20 10
Valdosta 65 41 70 44 63 / 0 0 10 30 10
Cross City 70 43 73 47 66 / 0 0 10 40 20
Apalachicola 64 41 66 45 63 / 0 0 10 40 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
LONG TERM/AVIATION/FIRE WX...BLOCK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
930 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
CALM CONDITIONS CAN BE EXPECTED THROUGH TODAY AS HIGH PRESSURE
BUILDS ACROSS CENTRAL INDIANA. SKIES ARE CURRENTLY BEGINNING TO
CLEAR OUT ACROSS THE NORTHWEST QUADRANT OF FORECAST AREA FROM
YESTERDAY/S DISTURBANCE. THIS CLEARING WILL SPREAD FROM NORTHWEST
TO SOUTHEAST OVER THE NEXT SEVERAL HOURS...EVENTUALLY RESULTING IN
CLEAR SKIES ACROSS ENTIRE FORECAST AREA SHORTLY AFTER DAYBREAK.
TEMPS WILL TOP OFF IN THE UPPER 30S/LOW 40S. LEANED TOWARD THE
WARMER NAM DUE TO AMPLE SUNSHINE AND A RETURN TO SOUTHWESTERLY
FLOW. CURRENTLY...TEMPS ACROSS CENTRAL INDIANA ARE RANGING FROM THE
LOW TO MID 20S WHERE CLEARING HAS ALREADY OCCURRED...TO LOW 30S
ACROSS THE SOUTHERN COUNTIES STILL UNDER CLOUD COVER. DEWPOINTS
ARE IN THE LOW 20S AND WINDS ARE LIGHT AND VARIABLE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
1430Z TAF UPDATE...STRATO CU DECK APPEARS TO BE RIGHT ON TRACK TO
MIX OUT AROUND 16Z THIS AFTERNOON. MADE FEW OR MINOR CHANGES TO
TAFS ATTM. PREVIOUS DISCUSSION FOLLOWS...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
619 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /THIS MORNING AND TODAY/...
CALM CONDITIONS CAN BE EXPECTED THROUGH TODAY AS HIGH PRESSURE
BUILDS ACROSS CENTRAL INDIANA. SKIES ARE CURRENTLY BEGINNING TO
CLEAR OUT ACROSS THE NORTHWEST QUADRANT OF FORECAST AREA FROM
YESTERDAY/S DISTURBANCE. THIS CLEARING WILL SPREAD FROM NORTHWEST
TO SOUTHEAST OVER THE NEXT SEVERAL HOURS...EVENTUALLY RESULTING IN
CLEAR SKIES ACROSS ENTIRE FORECAST AREA SHORTLY AFTER DAYBREAK.
TEMPS WILL TOP OFF IN THE UPPER 30S/LOW 40S. LEANED TOWARD THE
WARMER NAM DUE TO AMPLE SUNSHINE AND A RETURN TO SOUTHWESTERLY
FLOW. CURRENTLY...TEMPS ACROSS CENTRAL INDIANA ARE RANGING FROM THE
LOW TO MID 20S WHERE CLEARING HAS ALREADY OCCURRED...TO LOW 30S
ACROSS THE SOUTHERN COUNTIES STILL UNDER CLOUD COVER. DEWPOINTS
ARE IN THE LOW 20S AND WINDS ARE LIGHT AND VARIABLE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...RYAN
THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...
/TODAY THROUGH SATURDAY/
THE PERIOD BEGINS WITH A RATHER DEEP VORTEX TO THE EAST OF THE HUDSON
BAY REGION WITH WNW FLOW ALOFT LOCALLY WITH RATHER ZONAL FLOW
ACROSS THE EASTERN CONUS. A SHORTWAVE NOW MOVING THROUGH THE ROCKY MTN
REGION IS PROGGED TO MOVE INTO THE SOUTHERN PLAINS TODAY AND THEN
REACH THE MS AND LOWER OH VALLEYS ON FRI AFTERNOON AND MOVE ACROSS
THE REGION AND THE SE STATES ON FRI EVENING. AT THE SAME TIME...A
COUPLE OF NORTHERN STREAM SHORTWAVES ROTATING AROUND THE VORTEX AND A
110 TO 120 KT JET STREAK REACHING THE DAKOTAS AND THE NORTHERN PLAINS
TONIGHT AND INTO FRI WILL ROTATE DOWN INTO THE OH VALLEY ON FRI
NIGHT AND PASS EAST ON SAT. THIS COMBINATION WILL HELP TO CARVE OUT
AN EASTERN NOAM/EASTERN CONUS TROUGH FRI NIGHT INTO SAT...THE AXIS OF
WHICH SHOULD PASS EAST OF THE REGION BY THE END OF THE PERIOD. THIS
TROUGH WILL BRING SOME OF THE COLDEST AIR INTO THE REGION THAT WE
HAVE EXPERIENCED IN NEARLY A MONTH. 850 MB TEMPS ARE PROGGED TO
BOTTOM OUT AROUND -15C LATE IN THE PERIOD.
AN EXTENSIVE STRATOCU DECK LINGERS ACROSS MUCH OF THE LOWER OH VALLEY
AND EASTERN KY EARLY THIS MORNING...WITH A FEW PASSING LIGHT FLURRIES
FROM TIME TO TIME PER RADAR IMAGERY. THE CLOUD COVER HAS HELD TEMPS
NEAR THE FREEZING MARK. AT OR SLIGHTLY ABOVE IN MANY VALLEY LOCATIONS
AND A DEGREE OR TWO BELOW ON THE RIDGETOPS. SAT IMAGERY TRENDS
GENERALLY INDICATE THAT THIS CLOUD DECK WILL REMAIN IN GENERALLY THE
SAME PLACE THROUGH AT LEAST 12Z. LOCALLY THE 0Z/06Z NAM RH AT 850 MB
IS DOING A DECENT JOB IN DEPICTING THE LOW CLOUDS AND CLOUD COVER FOR
TODAY LEANED TOWARD A PATTERN OF HIGHER CLOUD COVER WHERE THE 850 MB
RH WAS HIGHEST. THIS LED TO QUITE A BIT OF CLOUD COVER MUCH OF THE
DAY. SO DESPITE A START THAT WILL BE WARMER THAN MOS GUIDANCE...THE
HOURLY T CURVE TODAY WILL PROBABLY STILL BE CLOSE TO THE 3 HOURLY MOS
GUIDANCE TEMPS AFTER 15Z. THIS LED TO A SLIGHT ADJUSTMENT IN MAX T
DOWN FOR TODAY. AS FOR THE FLURRY CHANCES...PLAN TO HAVE A PREFIRST
PERIOD FOR ISOLATED TO SCATTERED FLURRIES...WITH SOME OF THIS
LINGERING AN HOUR OR TWO PAST DAWN IN THE FAR SE.
THROUGHOUT THE DAY TODAY AND INTO TONIGHT...SFC HIGH PRESSURE OVER
THE MID MS VALLEY WILL BUILD TOWARD THE REGION AND SETTLE ACROSS THE
SOUTHEAST COAST BY LATE TONIGHT. HOWEVER...A WEAK SHORTWAVE NOW
MOVING THROUGH THE MO VALLEY REGION WILL BE PASSING BY THE NORTH AND
MAY HELP TO HOLD THE STRATOCU IN PLACE TODAY. DESPITE SFC HIGH
PRESSURE DOMINATING TONIGHT...A MIX OF SOME LOW AND HIGH CLOUDS
SHOULD LEAD TO AT LEAST PARTLY CLOUD SKIES. THIS SHOULD ALSO LIMIT
MIN T FOR VALLEY LOCATIONS AND MINIMIZE ANY RIDGE/VALLEY TEMPS SPLIT.
THE SHORTWAVE NOW OVER THE ROCKIES WILL TRANSPORT SOME GULF OF MEXICO
AND PACIFIC MOISTURE NORTH INTO THE MS VALLEY LATER TODAY AND TONIGHT
AND THEN EAST INTO THE OH VALLEY AND EASTERN KY ON FRI. THIS SYSTEM
SHOULD PRECEDE A RATHER STRONG COLD FRONT ASSOCIATED WITH THE
SHORTWAVES ROTATING AROUND THE VORTEX. THIS COLD FRONT IS EXPECTED TO
MOVE ACROSS THE REGION ON FRI NIGHT. OVERALL...THIS LEADS TO A BIT OF
A COMPLEX SCENARIO WITH TEMPS ALOFT AND 1000 TO 850 MB THICKNESSES
AND 1000 TO 500 MB THICKNESSES SUPPORTING SOME SNOW WITH PRECIP
ASSOCIATED WITH THE SHORTWAVE ON FRI AFTERNOON/EVENING. THERE WILL BE
SOME INITIALLY DRY AIR TO OVERCOME AND THE RESULTANT WET BULBING
SHOULD GRADUALLY CHANGE THE PRECIP TYPE OVER TO ALL SNOW DURING FRI
EVENING. THE HIGHEST ELEVATIONS ABOVE 2500 FEET WILL PROBABLY
EXPERIENCE ALL SNOW FROM THIS ON FRI AFTERNOON/EVENING. THE DEGREE OF
SOLAR INSOLATION OR LACK THEREOF ON FRI WILL BE KEY...BUT STRONGLY
LEANED HOURLY T AND MAX T TOWARD THE 3 HOUR TEMPS FROM THE MET MOS
FOR FRI AND TRENDED THESE TEMPS DOWN SEVERAL DEGREES FROM THE
PREVIOUS FORECAST.
TOP DOWN APPROACH FROM NAM FORECAST SOUNDINGS ALSO SUPPORTS SNOW
FALLING DESPITE SFC TEMPS IN THE MID TO UPPER 30S OR SO ON FRI
AFTERNOON NORTHERN AREAS AND SUPPORTS MORE OF A RAIN TO A RAIN AND
SNOW MIX BY EARLY EVENING IN THE SOUTH. THERE WILL PROBABLY BE TWO
PEAKS IN THE PRECIP CHANCES OVERALL WITH THIS...FIRST WITH THE
SHORTWAVE FRI AFTERNOON AND EVENING AND THEN AGAIN ALONG AND BEHIND
THE COLD FRONT WITH INSTABILITY/UPSLOPE SNOW SHOWERS KICKING IN AS
850 MB TEMPS DROP OFF RATHER QUICKLY. FOR NOW...HAVE LITTLE OR NO
SNOW ACCUMULATION DURING THE DAY ON FRI...AND THIS IS GENERALLY OVER
THE NORTHERN HALF OF THE CWA...WITH NO SNOW ACCUMULATION TO THE
SOUTH...EXCEPT PERHAPS SOME LIGHT ACCUMULATIONS ABOVE 2500 FEET. THEN
AS TEMPERATURES DROP BELOW FREEZING DURING THE EVENING HOURS...HAVE
TRANSITIONED PRECIP TYPE OVER TO ALL SNOW BY THE 2Z TO 3Z PERIOD. IF
THE 0Z NAM WERE TO VERIFY THEN THIS TRANSITION WOULD BE TOO SLOW. AT
THIS POINT...FELT THAT TRANSITIONING TO PRIMARILY SNOW EARLIER THAN
THE PREVIOUS FORECAST AND HIGHER POPS BY LATE FRI INTO FRI NIGHT WAS
IN ORDER BASED ON THE MOST RECENT SUITE OF MODEL GUIDANCE.
THE UPSLOPE ISOLATED TO SCATTERED SNOW SHOWERS AND FLURRIES SHOULD LINGER
WELL INTO SAT. COLD ADVECTION DURING THE DAY SHOULD LIMIT MAX T AND
HAVE UNDERCUT GUIDANCE A BIT FOR SAT MAX T. MOST PLACES SHOULD
STRUGGLE TO GET TO FREEZING. TEMPS ON SAT COULD EVEN END UP STEADY OR
FALL. AS FOR TEMPERATURES OVER THE REMAINDER OF THE PERIOD...UNDERCUT
GUIDANCE ON FRI AS WETBULBING FROM PRECIP AND CLOUD COVER MADE THE
MOS GUIDANCE MAX T FOR FRI DOUBTFUL.
BETWEEN FRI AFTERNOON AND SAT...HAVE GENERALLY ABOUT AN INCH OF
ACCUMULATION OUTSIDE OF THE CUMBERLAND VALLEY REGION...WITH AN INCH
OR LESS IN THE CUMBERLAND VALLEY REGION. AMOUNTS AS HIGH AS 2 TO 3
INCHES COULD FALL BY LATE SAT IN THE HIGHER TERRAIN OF THE SOUTHEAST
GENERALLY ABOVE 2000 FEET. OVERALL...IF MODEL TRENDS HOLD WITH THIS
SYSTEM...THIS COULD END UP BEING AN ADVISORY EVENT. DEPENDING ON
EVENTUAL AIR AND SFC TEMPS ON FRI AFTERNOON AND EVENING THESE AMOUNTS
COULD GO UP OR DOWN A BIT.
WILL HEIGHTEN THE SNOW THREAT IN THE HWO AND WILL ALSO CONSIDER AN
SPS TO HIGHLIGHT THE MORE WINTER LIKE WEATHER EXPECTED TO START THE
WEEKEND.
.LONG TERM.../SATURDAY NIGHT THROUGH WEDNESDAY/
ACTIVE PATTERN TAKING SHAPE THROUGH THE LONG TERM PORTION OF THE
FORECAST AS MODELS POINT TOWARDS A SPLIT FLOW DEVELOPING OVER THE
WRN U.S. TO START THE PERIOD...WITH RIDGING OVER THE HEART OF THE
CONUS AND THE DEPARTING TROF LIFTING THROUGH THE NORTHEAST. AN
EXPANSE OF SFC HIGH PRESSURE OVER THE PLAINS WILL BE IN THE PROCESS
OF BUILDING INTO THE MID MS AND OHIO VALLEYS ON SATURDAY NIGHT INTO
SUNDAY BEHIND THE DEPARTING SYSTEM...BRINGING DRIER WEATHER TO THE
AREA...ALBEIT WITH ANOTHER ROUND OF SOME OF THE COLDEST TEMPS OF THE
WINTER THUS FAR AS THE AO FORECAST CONTINUES TO TREND NEGATIVE
THROUGH THE CURRENT 14 DAY OUTLOOK PERIOD.
HIGH PRESSURE AND RIDGING ALOFT LOOKS TO EASE OFF TOWARDS THE
CAROLINAS ON MONDAY INVOKING A RETURN FLOW OF GOMEX MOISTURE AHEAD
OF THE FIRST IN A SERIES OF SHORT WAVES DEPICTED IN THE MEDIUM RANGE
MODELS AS DEVELOPING IN THE SRN STREAM OVER THE GREAT BASIN BEFORE
EJECTING OUT OF THE ROCKIES AND ACROSS THE PLAINS. OPERATIONAL
GUIDANCE CARRIES THE SFC REFLECTION INTO THE LOWER MS VALLEY MONDAY
NIGHT AS A SECONDARY SFC LOW DEVELOPS OVER THE NRN PLAINS AND BEGINS
TREKKING TOWARDS THE GREAT LAKES. THE COMBINED RESULT SPREADS PRECIP
OVER THE OHIO VALLEY AND INTO ERN KY FROM MONDAY NIGHT THROUGH
TUESDAY BEFORE TAPERING OFF TUESDAY NIGHT. THE GFS REMAINS A TAD
FASTER THAN THE ECMWF AT THIS POINT BUT BOTH OPERATIONAL MODELS
SUPPORT SHOWERS MOVING INTO THE AREA BY MONDAY NIGHT. GIVEN THE
PATTERN AND TEMPERATURE PROFILES...HAVE CONSIDERED SNOW FOR THE
OVERNIGHT HOURS ALTHOUGH SFC TEMPS LOOK TO BE JUST A LITTLE TOO WARM
AT THIS POINT FOR ANY SIGNIFICANT ACCUMULATIONS. HOWEVER...THE
09.00Z GFS FCST SOUNDINGS DO DEPICT A BRIEF WINDOW AROUND TUESDAY
MORNING THAT WOULD SUPPORT FREEZING RAIN. THIS FAR OUT...HAVE HEDGED
WITH A CHANCE OF RAIN OR SNOW MONDAY NIGHT BEFORE LINGERING SHOWERS
ON TUESDAY TRANSITION BACK OVER TO RAIN.
MODELS BRING FLEETING HIGH PRESSURE UP THE OHIO VALLEY AROUND THE
MIDDLE OF THE WEEK TO END THE PERIOD BUT THE NEXT SYSTEM IS ALREADY
APPEARING ON THE HORIZON WITH THE GFS AGAIN TAKING THE LEAD AND
OUTPACING THE EURO BY ABOUT A HALF A DAY...WHICH MAY JUST PAN OUT
GIVEN THE PROGRESSIVE FLOW. WILL KEEP CHANCE POPS FROM THE EXTENDED
INITIALIZATION TO CLOSE OUT THE PERIOD FOR NOW AND HOPE FOR A BETTER
CONSENSUS IN THE NEXT ITERATIONS.
&&
.AVIATION.../12Z TO 12Z/
CEILINGS REMAIN GENERALLY NEAR THE MVFR/VFR BREAK AT THIS POINT
AS LOW LEVEL MOISTURE REMAINS BEHIND YESTERDAYS SYSTEM. THE OVERALL
TREND IS TO VFR...BUT CARRIED A TEMPO FOR THE FIRST TWO HOURS AT ALL
THREE SITES AS SOME REGIONAL OBS ARE 2KFT OR BELOW. THE STRATOCU
SHOULD GRADUALLY SCATTER OUT THROUGH AROUND 19Z...ERODING FROM THE
EAST AND NORTHEAST AND WEST. A FEW TO SCT STRATOCU MAY LINGER AS LAST
AS 6Z...WITH MAINLY MID AND HIGH CLOUDS INCREASING LATE IN THE PERIOD
AHEAD OF THE NEXT SYSTEM. HOWEVER...DESPITE THE ANTICIPATED CLOUD COVER
EARLY IN THE PERIOD AND LATE IN THE PERIOD...VFR SHOULD PREDOMINATE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...JP/SBH
LONG TERM....MB
AVIATION...JP
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
517 AM CST Thu Feb 9 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Widespread stratus once again in place early this morning, which has
held overnight temperatures on the warm side for locations beneath
this cloud deck. Outside of the stratus, temperatures have dropped
quite a bit with lows currently in the teens across northeast Missouri.
Similar to yesterday, believe the stratus will be slow to erode today
which is supported by the latest RUC condensation deficits and
various BUFR soundings. However, overall model performance has been
poor in handling the low level moisture over the past couple of days
so confidence is necessarily high.
Surface ridge will shift into the lower to mid Mississippi valley
today allowing low level winds to swing around to the southwest.
This will advect warmer temperatures into the area although lighter
speeds will prevent significant warming. Mixing to around H9-H85
should help break up clouds to some degree. However, given the
expectation of prolonged, at least broken cloud cover, knocked a few
degrees off of temperatures for this afternoon.
Advertised Hudson Bay low will settle southward through the end of
the week with pronounced short wave energy diving southward into the
central CONUS. Given the meridional nature of the upper height
pattern by the beginning of the weekend in response to amplified
ridging across the western US/Canada, expect a decent chunk of arctic
air to dislodge and plunge southward into the region. Expect the sfc
baroclinic boundary to slide through the area Friday morning with CAA
taking shape thereafter. The main story through the weekend will then
be the cold temperatures as most locations will not see readings
above the freezing mark for several days.
Deep eastern US upper troughing establishes by the middle of the
weekend with upper short wave ridging sliding overhead by Sunday. A
more progressive upper flow pattern then establishes across the
CONUS through the end of the weekend and through the first half of
next week. Models continue to be in good agreement with the timing
of the next progressive short wave trough to affect the area by
Sunday night and Monday. Given the run to run consistency, felt
comfortable continuing to raise POPS for this time period. There
still appears to be a decent shot at accumulating snowfall across
most of the forecast area as this system swings through. The main
limiting factor at this point appears to be the speed at which the
system progresses through the area. Nevertheless, many areas may
finally be in store for the first decent snowfall of the season.
There looks to be a short reprieve on Tuesday before the next system
in the progressive pattern affects the area by Wednesday. Models
have not displayed as good run to run consistency during this period
and will remain close to the consensus numbers to account.
Deroche
&&
.AVIATION...
For the 12Z TAFS...ceilings will be the main challenge for the first
half of the valid period. Current ceilings around 3k-3.5 ft should
lift to around 5k ft by this afternoon and then begin to lift further
and scatter out this evening. Winds are expected to be light through
most of the valid period but will veer through the day as surface
high pressure moves east of the area. A front is expected to begin
moving through the area veer late in the valid period which will
switch winds around to the northwest by 09-12Z Friday. Winds will
also increase behind the front and lower level clouds should fill in
an hour or two behind the front as well.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
621 AM EST THU FEB 9 2012
.SYNOPSIS...
BROAD HIGH PRESSURE WILL BUILD INTO EASTERN NC THROUGH TONIGHT. A
MODIFIED ARCTIC COLD FRONT WILL MOVE THROUGH ON SATURDAY WITH A
STRONG PUSH OF MUCH COLDER AIR BEHIND IT. ARCTIC HIGH PRESSURE OVER
THE NORTHERN PLAINS SATURDAY WILL MOVE SOUTHEAST...BECOMING CENTERED
OVER THE AREA ON MONDAY. THE HIGH WILL SHIFT OFFSHORE MONDAY NIGHT
AS ANOTHER DISTURBANCE MOVES IN FOR TUESDAY OR WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 315 AM THUR...THE FA IS SANDWICHED BETWEEN DEPARTING LOW
PRESSURE TO THE NORTHEAST AND APPROACHING SFC HIGH PRES TO THE WEST
EARLY THIS MORNING. MOST OF E NC IS EXPERIENCING CLEAR SKIES...
EXCEPT FOR SOME LINGERING STRATUS ACROSS THE NE PORTIONS/OBX...
WHERE WRAP AROUND MOISTURE IS LINGERING. TEMPS ARE CURRENTLY IN THE
LOWER TO MID 30S INLAND WITH 40S NEAR THE IMMEDIATE COAST. SFC HIGH
PRES WILL BUILD IN TODAY WITH LIGHT NORTHERLY WINDS UNDER MOSTLY
SUNNY SKIES. UPR FLOW WILL BECOME ZONAL WITH SUBTROPICAL JET FEEDING
SOME INCREASE IN HIGH LEVEL CIRRUS TOWARD THE END OF THE DAY. LOW
LEVEL THICKNESSES INDICATE MAX TEMPS STRUGGLING TO REACH THE 50
DEGREE MARK IN MOST AREAS...WITH MID 40S FOR THE OBX WHERE A STIFF
NORTH BREEZE WILL PERSIST.
&&
.SHORT TERM /TONIGHT/...
AS OF 315 AM THUR...X-SECTION ANALYSIS INDICATES FURTHER INCREASING
OF UPR LEVEL MOISTURE AS WEAK IMPULSE SLIDES THROUGH IN MEAN
WESTERLY FLOW ALOFT. THIS WILL HAVE IMPLICATIONS ON MIN TEMPS
OVERNIGHT. SFC HIGH WILL BE CENTERED OVERHEAD...THOUGH WITH THE
THICKER CLOUD CANOPY EXPECTED...IDEAL RADIATIONAL COOLING CONDITIONS
WILL NOT BE REALIZED...SO WENT A BIT HIGHER FOR MIN TEMPS...WITH
MOST AREAS REMAINING AROUND THE FREEZING MARK. SHOULD CIRRO STRATUS
DECK THIN OR MOVE OUT BEFORE 12Z...MIN TEMPS WOULD BE A BIT
COOLER...IN THE MID 20S...THAN CURRENTLY ADVERTISED.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE SURFACE HIGH MOVES OFF OF THE COAST
FRIDAY WITH RETURN SW FLOW HELPING TO BOOST HIGH TEMPERATURES TO
AROUND 60 DEGREES. CLOUDS WILL BE ON THE INCREASE AHEAD OF NEXT
SYSTEM LATE IN THE DAY WITH A SMALL RISK OF A STRAY SHOWER OR TWO
TOWARDS EVENING AS LOW LEVEL WARM ADVECTION COMMENCES. AMPLITUDE OF
DIGGING SHORTWAVE/LONG WAVE TROUGH FRIDAY NIGHT WILL HAVE ENOUGH
AMPLITUDE TO TAP THE ATLANTIC. WITH MORE MOISTURE TO WORK WITH
AND GOOD LIFT ASSOCIATED WITH A STRONG SHORTWAVE...EXPECT MORE
WIDESPREAD COVERAGE OF PRECIPITATION. WILL INCREASE POPS TO 50%.
MET/MAV MOS WERE ALL INDICATING LIKELY POPS DURING THIS TIME AND
IF THIS TREND CONTINUES POPS WILL BE RAISED ON SUBSEQUENT UPDATES.
THE DEEPENING LONG WAVE TROUGH OVER THE EASTERN US WILL FACILITATE
CYCLOGENESIS OVER OR JUST OFFSHORE OF EASTERN NC FRIDAY NIGHT WITH
THE STRENGTHENING LOW MOVING JUST OFF THE EASTERN SEABOARD ON
SATURDAY. CONSENSUS OF THE GUIDANCE IS FOR MOST OF THE SIGNIFICANT
PRECIPITATION TO BE OVER BY 12Z SATURDAY BUT WILL HOLD ONTO SLIGHT
CHANCE POPS ALL DAY AS BASE OF UPPER TROUGH MOVES THROUGH THE
REGION. THE DEEPENING LOW WILL PRODUCE STRONG NW WINDS ACROSS THE
AREA. THESE NW WINDS WILL CAUSE MUCH COLDER AIR TO SWEEP INTO
EASTERN NC.
ANOTHER SHORTWAVE WILL ROTATE AROUND THE BASE OF THE UPPER TROUGH
SATURDAY EVENING. MOISTURE WILL BE VERY LIMITED WITH THIS SYSTEM
AND WHAT MOISTURE THERE IS WILL PASS TO OUR NORTH. WILL STILL HANG
ONTO A SLIGHT CHANCE FOR EVENING SNOW SHOWERS DUE TO THE STRENGTH
OF THE UPPER SYSTEM BUT NOT EXPECTING ANY SIGNIFICANT ACCUMULATIONS
IF THE SNOW SHOWERS DEVELOP.
AN ARCTIC AIR INTRUSION WILL BE MAIN FOCUS FOR LATE SATURDAY NIGHT
THROUGH THE MONDAY PERIOD AS STRONG HIGH PRESSURE BUILDS OVER THE
AREA WITH BELOW NORMAL TEMPERATURES EXPECTED. THE COLD AIR WILL
PEAK OVER THE AREA SUNDAY WHEN HIGHS WILL STRUGGLE TO REACH THE
LOWER 40S. RETURN FLOW FROM HIGH PRESSURE MOVING OFFSHORE ALONG WITH
WAA AND SHORT WAVES ALOFT WILL SUPPORT SLIGHT CHANCE POPS FOR
TUESDAY THROUGH WEDNESDAY...ALONG WITH MODERATING TEMPS. THERE
STILL WERE SIGNIFICANT DIFFERENCES IN THE MODELS FOR THE FORECAST
FROM TUESDAY AND BEYOND.
THE LONG RANGE FORECAST INDICES WERE SENDING MIXED SIGNALS FOR MID
FEBRUARY. THE PNA IS FORECAST TO REMAIN STRONGLY POSITIVE THROUGH
MID FEBRUARY WHICH USUALLY MEANS COLDER TEMPERATURES FOR THE
EASTERN US. HOWEVER...THE NAO AND AO HAVE BEEN POSITIVE FOR MUCH
OF THIS WINTER AND THIS HAS BEEN THE REASON FOR OUR MILD WINTER
THUS FAR. THE CPC ENSEMBLE FORECAST FOR BOTH THESE INDEXES THROUGH
FEBRUARY REMAIN POSITIVE ALTHOUGH THE GFS WAS INDICATING A PERIOD
OF NEGATIVE AO. THE LATEST CPC FORECAST HAS SIDED WITH THE ENSEMBLES
AND IS CALLING FOR A CONTINUATION OF THE MILD TEMPERATURES WITH
BETTER CHANCES FOR MUCH NEEDED RAINFALL DURING THE NEXT 7-14 DAYS.
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 630 AM THUR...SHALLOW INVERSION WILL BREAK SHORTLY AFTER
SUNRISE THIS MORNING...AND ANY LIGHT FOG WILL BURN OFF THEN. LIGHT
NORTHERLY FLOW EXPECTED DURING THE DAY UNDER MOSTLY SUNNY SKIES.
WINDS DECOUPLE WITH SFC HIGH LOCATED OVERHEAD TONIGHT. SCT/BKN
CIRRUS EXPECTED TO OVER SPREAD THE AREA TONIGHT...SO FOG/BR
POTENTIAL IS QUESTIONBLE AT BEST FOR TONIGHT.
LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 345 AM THURSDAY...VFR CONDITIONS ARE EXPECTED FOR THE
MAJORITY OF THE LONG TERM FORECAST PERIOD. LOCAL BRIEF MVFR
CONDITIONS ARE POSSIBLE WITH LIGHT SHOWER ACTIVITY LATE FRIDAY.
MORE SUBSTANTIAL RAINFALL COULD OCCUR FRIDAY NIGHT INTO SATURDAY
MORNING WITH A BETTER CHANCE FOR SUB VFR CONDITIONS. GUSTY NW TO
N WINDS WILL ACCOMPANY AN ARCTIC AIR INTRUSION LATE SATURDAY INTO
SUNDAY.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 630 AM THUR...EXTENDED SCA SEVERAL MORE HOURS...UNTIL 10
AM...AS GRADIENT IS SLOW TO RELAX DUE TO CONTINUING DEEPENING OF
THE DEPARTING LOW PRES TO THE NORTHEAST. RUC HAS CONTINUED TO
PERFORM WELL IN REGARDING 3 HOURLY PRES RISES AND WINDS FOR THE
COASTAL WATERS...AND HAS THEM DIMINISHING AFTER MID MORNING THIS
MORNING. BUOY 10NE OF DUCK HAS BEEN OBSERVING 6 FOOT SEAS OVER THE
LAST SEVERAL HOURS AND WILL CONTINUE TO DO SO THROUGH MID
MORNING... BEFORE SUBSIDING AFTER THAT.
PREVIOUS DISCUSSION...AS OF 315 AM THUR...GRADIENT WILL SLOWLY
SUBSIDE TODAY AS DEEP LOW PRESSURE PULLS AWAY TO THE CANADIAN
MARITIMES AND SFC HIGH PRES APPROACHES. 20-25 KT WINDS EARLY THIS
MORNING WILL SUBSIDE TO 15 TO 20 KT FOR THE OUTER WATERS...AND
DIMINISH FURTHER TO 10 TO 15 KT THIS AFTERNOON. THE HIGH WILL
BUILD IN OVER THE WATERS THIS EVENING...WITH WINDS GENERALLY 5 KT
AND BACKING WESTERLY LATE. SEAS WILL FOLLOW SUIT AND SUBSIDE
THROUGH THE PERIOD...BECOMING 1 TO 3 FEET LATE TONIGHT.
LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 345 AM THURSDAY...LIGHT WINDS AND 2-3 FT SEAS ARE FORECAST
FOR FRIDAY AS HIGH PRESSURE SLOWLY MOVES EAST OF THE WATERS. SW
WINDS WILL INCREASE TO 15 TO 20 KT AND SEAS TO 4 TO 5 FT FRIDAY
NIGHT AND SATURDAY AHEAD OF A DEVELOPING AREA OF LOW PRESSURE
VICINITY OF THE NC COAST. DETERIORATING CONDITIONS EXPECTED LATE
SATURDAY INTO SUNDAY AS THE LOW MOVES NE OF THE WATERS AND STRONG
NW FLOW DEVELOPS OVER THE WATERS. STRONG SMALL CRAFT TO GALE FORCE
WINDS WILL BE POSSIBLE. WILL INCREASE WINDS TO 30 KT WITH THIS
ISSUANCE AND WILL HAVE TO MONITOR THREAT FOR GALES SATURDAY WITH
SMALL CRAFT CONDITIONS EXPECTED THROUGHOUT SUNDAY. SEAS WILL PEAK
AT 7-9 FT SATURDAY AND EARLY SUNDAY. WINDS ARE FORECAST TO DIMINISH
MONDAY WITH THE SURFACE HIGH CENTER BUILDING OVER THE WATERS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ150-
152.
&&
$$
SYNOPSIS...TL
NEAR TERM...TL
SHORT TERM...TL
LONG TERM...JBM/JME
AVIATION...TL/JME
MARINE...TL/JME
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
949 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY. ARCTIC
COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY. COLD
SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...SATELLITE IMAGERY CONFIRMS 12Z MODEL DATA OF LOW
LEVEL MOISTURE/CLOUDS TRAPPED UNDER INVERSION...MAINLY SOUTH AND
WEST...WILL BE SLOW TO DISSIPATE THIS AFTERNOON. WILL UPDATE TO HOLD
CLOUDS LONGER INTO EARLY AFTERNOON AND LOWER HIGHS UNDER THE CLOUD
SHIELD A COUPLE OF DEGREES. NO PRECIP.
PREVIOUS DISCUSSION BELOW...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD
SHIFT. CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF
NE KY WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A
GOOD HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU
EARLY MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER
E TO ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS
TO DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
15Z THURSDAY THRU 12Z FRIDAY...
LOW LEVEL MOISTURE TRAPPED UNDER HIGH PRESSURE INVERSION. AREAS OF
MVFR CEILINGS SOUTH AND EAST OF A HTS-CRW-EKN LINE WILL LIFT BY 18Z
TO VFR AND GENERALLY DISSIPATE BY 22Z AS MIXING OCCURS.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W BY
12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLEARING COULD VARY A FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
555 AM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY.
ARCTIC COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY.
COLD SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
11Z UPDATE...
MAIN ISSUE TDY CONT TO BE TIMING OF EROSION OF STRATUS LYR. THUS
FAR...SATELLITE IMAGERY CONFIRMS FCST ON TRACK REGARDING SKY GRIDS
AND DEGREE OF CLRING. WILL CONT TO LEAN ON RUC RH FIELDS NEAR H85
FOR CLDS TDY. AS A RESULT...JUST SOME TWEAKING OF SKY GRIDS
NEEDED...BASICALLY TO KEEP MORE IN THE WAY OF CLD ACROSS NE KY AND
SW WV THRU MIDDAY. STILL...GIVEN HOW SHALLOW THIS MOISTURE DEPTH
IS...THINK WITH DAYTIME HEATING...MUCH OF THIS SHOULD MIX OUT OR
ATLEAST BEGIN TO BREAK UP. CONT TO KEEP THOSE AREAS A COUPLE
DEGREES COOLER.
PREVIOUS DISCUSSION BELOW...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD
SHIFT. CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF
NE KY WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A
GOOD HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU
EARLY MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER
E TO ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS
TO DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
12Z THURSDAY THRU 12Z FRIDAY...
CLEARING WILL WORK THRU NORTHERN MTNS BY 13Z...WITH SE OH AND
NORTHERN LOWLANDS GENERALLY CLR. GENERALLY LOW END VFR CIGS
LINGERS THRU 15Z ACROSS NE KY...SOUTHERN COALFIELDS...SW VA. THIS
INCLUDES KHTS.
ANY REAMING STRATUS BECOMES MORE SCT-BKN MIDDY BEFORE
TRYING TO MIX OUT IN AFTN. ELSEWHERE GENERALLY LOOKING AT JUST
SOME AFTN CIRRUS OR SCT 4 TO 5KFT BASE CU.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W
BY 12Z FRI.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF CLEARING COULD VARY A FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M H H H H H H H H H H
HTS CONSISTENCY M H H H H H H H H H H H
BKW CONSISTENCY M M M H M M M M M H H H
EKN CONSISTENCY M M M H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...30
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
520 AM CST THU FEB 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
250 AM CST THU FEB 9 2012
MAIN FORECAST CONCERNS ARE ON LIGHT SNOW/FLURRY CHANCES TONIGHT
THROUGH FRIDAY AND HIGH TEMPERATURES FRIDAY INTO SATURDAY BEHIND
THE ARCTIC COLD FRONT.
CURRENT SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
CENTRAL ONTARIO WEST THROUGH SOUTHERN MANITOBA INTO SOUTHERN
SASKATCHEWAN. THE FRONT WAS MOVING SOUTH EARLY THIS MORNING. AN
AREA OF STRATUS WAS NOTED ACROSS EASTERN NEBRASKA/SOUTHWEST
IOWA...MOVING EAST AND SLIGHTLY NORTHEAST. WILL HAVE TO KEEP A
CLOSE WATCH ON THIS AREA OF STRATUS AS SOUTHWEST WINDS INCREASE
AHEAD OF THE FRONT THIS MORNING INTO THIS AFTERNOON WITH THE
POSSIBILITY OF THE STRATUS ADVECTING INTO THE FORECAST AREA.
HIGH PRESSURE WILL SLIDE SOUTH OF THE REGION TODAY AS THE ARCTIC
COLD FRONT APPROACHES THE REGION. THE HRRR DEVELOPS AN AREA OF
STRATUS ACROSS SOUTHWEST/SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA
LATE THIS MORNING...WITH THE STRATUS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS AFTERNOON. FORECAST SOUNDINGS ACROSS
SOUTH CENTRAL MINNESOTA AND NORTHEAST IOWA SHOW VERY DRY AIR IN
THE LOWER LEVELS OF THE ATMOSPHERE LATE THIS MORNING INTO THIS
AFTERNOON. SURFACE DEWPOINTS ACROSS THIS AREA ARE ONLY IN THE
SINGLE DIGITS TO LOWER TEENS WITH THE ONLY APPRECIABLE LOW LEVEL
MOISTURE NOTED IN THE AREA OF STRATUS ACROSS EASTERN NEBRASKA INTO
SOUTHWEST IOWA. PLAN ON MOSTLY SUNNY SKIES THROUGH EARLY AFTERNOON
WITH CLOUDS INCREASING DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS AS THE COLD FRONT MOVES INTO THE FORECAST AREA. THE FRONT IS
EXPECTED TO BE POSITIONED FROM WESTERN LAKE SUPERIOR INTO
SOUTHWEST MINNESOTA BY 6 PM THIS EVENING. LOOK FOR THE FRONT TO
SWEEP ACROSS THE AREA DURING THE EVENING HOURS. THE BEST FORCING
FOR PRECIPITATION APPEARS TO BE RIGHT ALONG AND SLIGHTLY TRAILING
THE COLD FRONT. WOULD EXPECT TO SEE A FEW FLURRIES OR LIGHT SNOW
SHOWERS THIS EVENING INTO THE OVERNIGHT HOURS AS THE FRONT MOVES
THROUGH. NAM FORECAST SOUNDINGS SHOW THE POTENTIAL FOR SNOW
SHOWERS...MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. THE GFS
SHOWS A BRIEF WINDOW OF FLURRIES/LIGHT SNOW SHOWERS THIS EVENING
BEFORE DRY/COLD AIR MOVES IN. A BRIEF SHOT OF ISENTROPIC LIFT
NOTED IN THE LATEST NAM SOLUTION ON THE 270 THROUGH 280 K SURFACES
THIS EVENING WITH CONDENSATION PRESSURE DEFICITS LOWERING TO
AROUND 7 MB WITHIN THIS LAYER. IF LIGHT SNOW DEVELOPS...LITTLE OR
NO ACCUMULATION IS EXPECTED WITH THIS ACTIVITY. WILL INCLUDE A
SLIGHT CHANCE OF VERY LIGHT SNOW ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN.
SLIGHTLY HIGHER CHANCES FOR SNOW ACROSS NORTH CENTRAL WISCONSIN.
OTHERWISE...PLAN ON MOSTLY CLOUDY SKIES OVERNIGHT WITH LOW
TEMPERATURES RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE UPPER TEENS ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
AN UPPER LEVEL TROUGH IS EXPECTED TO PUSH INTO THE AREA ON
FRIDAY...WITH PV15 SURFACES DIPPING TO 540 MB AS IT MOVES IN. THE
COLDEST AIR ALOFT WILL FILTER IN BEHIND THIS WAVE WITH 900 MB
TEMPERATURES FALLING TO -17C BY FRIDAY AFTERNOON. A RATHER NICE PV
ADVECTION SIGNAL MOVING ACROSS THE FORECAST AREA FRIDAY
MORNING...WITH PV ADVECTION IN THE 500-300 MB LAYER OF AROUND 37
PVU/S. EVEN WITH THIS UPPER LEVEL FORCING...THE LOWER LEVEL ARE
VERY DRY LIMITING OVERALL SNOW CHANCES AS THE WAVE MOVES
THROUGH...WITH LITTLE OR NO CONTRIBUTION FROM FORCING ALOFT.
HOWEVER...GIVEN THE COLD AIR AT 900 MB PRODUCING STEEP LAPSE
RATES...CANNOT RULE OUT A FEW CONVECTIVE SNOW SHOWERS. HAVE
LOWERED PRECIPITATION CHANCES SLIGHTLY. WILL MAINTAIN A SLIGHT
CHANCE OF SNOW SHOWERS THROUGH THE DAY ON FRIDAY EAST OF THE
MISSISSIPPI RIVER. OCCASIONAL FLURRIES CAN BE EXPECTED ACROSS THE
ENTIRE FORECAST AREA. LOOK FOR HIGH TEMPERATURES TO RANGE FROM THE
TEENS ACROSS NORTHERN WISCONSIN TO AROUND 20 ACROSS FAR SOUTHWEST
WISCONSIN. COLD SURFACE HIGH PRESSURE IS EXPECTED TO BUILD INTO
THE FORECAST AREA FRIDAY NIGHT...WITH THE CENTER OF THE HIGH
POSITIONED OVER THE DAKOTAS. LOOK FOR CLOUDS TO GRADUALLY DECREASE
FROM NORTH TO SOUTH LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING
AS DRIER LOW LEVEL AIR ADVECTS IN AND ERODES ANY LINGERING
STRATUS. LOW TEMPERATURES FRIDAY NIGHT WILL BE ON THE CHILLY
SIDE...WITH LOWS RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE SINGLE DIGITS ABOVE ZERO ACROSS
NORTHEAST IOWA.
LOW PRESSURE WILL DROP SOUTH ACROSS JAMES BAY INTO CENTRAL QUEBEC ON
SATURDAY. MEANWHILE...COLD HIGH PRESSURE IS EXPECTED TO BE CENTERED
OVER THE DAKOTAS. THIS WILL PRODUCE A TIGHT PRESSURE GRADIENT ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY WITH WEST WINDS INCREASING INTO
THE 10 TO 18 MPH RANGE. HIGHS ON SATURDAY WILL BE MAINLY IN THE
TEENS TO AROUND 20 ACROSS NORTHEAST IOWA INTO FAR SOUTHERN
WISCONSIN. PLAN ON WIND CHILLS IN THE SINGLE DIGITS ABOVE TO
SINGLE DIGITS BELOW ZERO ON SATURDAY. LOOK FOR ONE MORE CHILLY
NIGHT SATURDAY NIGHT WITH LOWS DROPPING INTO SINGLE DIGITS. WEST
WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT AS THE RIDGE AXIS
MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
250 AM CST THU FEB 9 2012
09.00 MEDIUM RANGE MODELS IN AGREEMENT ON SUNDAY SHOWING AN UPPER
RIDGE ACROSS THE FORECAST AREA WITH A TROUGH DIVING INTO THE
SOUTHWEST CONUS. WARMER TEMPERATURES ARE ON TAP FOR SUNDAY AS 850
MB TEMPS WARM TO AROUND -4 C BY SUNDAY AFTERNOON. PLAN ON MOSTLY
SUNNY SKIES ON SUNDAY WITH HIGH TEMPERATURES IN THE 20S. THE TROUGH
WILL EJECT INTO THE CENTRAL/NORTHERN PLAINS LATE SUNDAY NIGHT AND
MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY ON MONDAY. THIS SYSTEM
IS EXPECTED TO BRING LIGHT SNOW TO THE FORECAST AREA...WITH LIGHT
ACCUMULATIONS POSSIBLE. LATEST GUIDANCE SUGGEST 1 TO 3 INCHES OF
ACCUMULATION. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW MODEL
RUNS. IF TRENDS CONTINUE...SNOW CHANCES WILL LIKELY BE INCREASED
SIGNIFICANTLY. GOOD MODEL AGREEMENT TUESDAY INTO WEDNESDAY SHOWING
ZONAL FLOW ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MODELS MUCH
DRIER THIS RUN ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WITH QUIET ZONAL FLOW ACROSS THE REGION. HAVE DECIDED
TO REMOVE PRECIPITATION CHANCES THROUGH THIS PERIOD. LOOK FOR HIGH
TEMPERATURES IN THE LOW TO MID 30S TUESDAY INTO WEDNESDAY...WITH
OVERNIGHT LOWS IN THE 20S.
&&
.AVIATION...TODAY AND TONIGHT
520 AM CST THU FEB 9 2012
THE MAIN FOCUS WITH THE TAFS IS ON THE COLD FRONT THAT COMES
THROUGH TONIGHT AND WHETHER THE CEILINGS WILL DROP TO MVFR AS IT
PASSES. THIS FRONT CURRENTLY STRETCHES ACROSS SOUTHERN ONTARIO AND
MANITOBA NEAR WINNIPEG AND IS TIMED TO REACH RST AND LSE AROUND
5-6Z TONIGHT. SOME SNOW SHOWERS OR FLURRIES WILL BE POSSIBLE AS
WELL...BUT WAS NOT CONFIDENT ENOUGH TO PUT ANY VISIBILITY
RESTRICTIONS IN THE FORECAST. HOWEVER...CEILINGS DO SEEM TO BE A
GOOD BET TO DROP DOWN WITH SOME MOISTURE GETTING TRAPPED IN THE
LOW LEVELS BEHIND AND ALONG THE FRONT. WINDS WILL ALSO BE AN ISSUE
AHEAD AS WELL AS BEHIND THE FRONT WITH GUSTS GETTING UP INTO THE
20 TO 25KT RANGE ON BOTH ENDS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 AM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS DENVER CO
1259 PM MST THU FEB 9 2012
.UPDATE...MORE CLOUDS UPSTREAM MOVING ACROSS PLAINS...NEEDED TO
UPDATE SKY GRIDS. RADAR SHOWING ALOT OF ECHOES ACROSS THE
PLAINS...APPEARS NOTHING HITTING GROUND AT THIS TIME. WILL NOT
INCLUDE POPS AT THIS POINT.
&&
.AVIATION...LOTS OF STRATOCU ACROSS PLAINS. CEILINGS HAVE DROPPED
TO AROUND 4500-5500 AGL. HAVE UPDATED DIA TAF AS A
RESULT. KEPT THE BROKEN LAYER THROUGH 23Z AS SUGGESTED BY LATEST
FORECAST SOUNDINGS. SHOULD SEE THINGS BECOMING SCATTERED AFTER 00Z.
&&
.PREV DISCUSSION... /ISSUED 1056 AM MST THU FEB 9 2012/
UPDATE...SHORTWAVE CURRENTLY PASSING ACROSS AREA...STILL QUITE A
BIT OF CLOUDS ACROSS MUCH OF CFWA. WEB CAMS AND RADAR LOOPS
SHOWING PERSISTANT LIGHT SNOW OVER THE MOUNTAINS...MAINLY ALONG
THE CONTINENTAL DIVIDE. DESPITE SUBSIDENCE THIS AFTERNOON BEHIND
EXITING SHORTWAVE...BOTH NAM AND RUC STILL KEEP QUITE A BIT OF
CLOUD OVER THE MOUNTAINS...ALONG WITH LIGHT QPF/SNOW AMOUNTS ALONG
THE DIVIDE. BASED ON THE CURRENT TRENDS...WILL NEED TO KEEP A
CHANCE OF SNOW OVER THE HIGHER PEAKS THROUGH MUCH OF THE
AFTERNOON. OTHERWISE...TREND TOWARD DECREASING CLOUDS STILL
LOOKING ON TRACK FOR NOW. REST OF FORECAST TRENDS ALSO ON TRACK.
AVIATION...CURRENT TAF TRENDS SEEM ON TRACK...DID KEEP THE BROKEN
MID LEVEL A BIT LONGER. LATEST NAM AND GFS GUIDANCE SHOWING A
BROKEN 6000-7000 AGL DECK THROUGH 21Z. NOT SURE IF THIS WILL PAN
OUT BASED ON AREA OBSERVATIONS. A BIT OF STRATUS TOWARDS CASPER
WITH SOME LIGHT SNOW...DON`T THINK IT WILL PUSH INTO COLORADO ANY
TIME SOON.
PREV DISCUSSION... /ISSUED 400 AM MST THU FEB 9 2012/
SHORT TERM...WEAK SHORTWAVE MOVING ACROSS COLORADO THIS MORNING.
MOISTURE WILL BE DIMINISHING FROM THE NORTHWEST THOUGH A FEW SNOW
SHOWERS MAY HANG ON INTO THE AFTERNOON IN THE HIGH MOUNTAINS. NOT A
LOT OF TEMPERATURE ADVECTION WITH THIS TROUGH...A WARMER START TO
THE DAY AND A BIT MORE MIXING AS A RESULT...SO WILL TRY AGAIN FOR A
WARMER DAY OVER THE PLAINS. WE WILL LIKELY SEE THE SAME TEMPERATURE
PATTERN HOWEVER...JUST NOT AS EXTREME. STILL NEED TO DROP FORECAST
HIGHS ON THE PLAINS...UNDERCUTTING MOS GUIDANCE IN MOST AREAS DUE TO
THE SNOW COVER. MOSTLY CLEAR SKIES THIS EVENING THEN SOME INCREASE
IN CLOUD COVER POSSIBLE AGAIN TOWARD MORNING. COOLED LOWS IN THE
MOUNTAIN VALLEYS...BUT NOT AS MUCH AS GUIDANCE SINCE THERE IS STILL
SOME MOISTURE AND PROBABLY SOME CLOUD COVER AGAIN TOWARD MORNING.
LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED FRIDAY INTO FRIDAY
NIGHT. THEN AN UPPER RIDGE MOVES ACROSS THROUGH SATURDAY. ZONAL
FLOW EARLY ON SATURDAY BECOMES WEST-SOUTHWESTERLY BY SATURDAY
AFTERNOON...THEN SOUTHWESTERLY SATURDAY NIGHT. THE SYNOPTIC SCALE
ENERGY IS BENIGN FRIDAY INTO MID DAY SATURDAY...THEN WEAK UPWARD
VERTICAL VELOCITY IS PROGGED BY AFTERNOON THROUGH SATURDAY NIGHT.
THE LOW LEVEL PRESSURE AND WIND FIELDS ELUDE TO NORMAL DIURNAL WIND
PATTERNS FOR FRIDAY. BY FRIDAY NIGHT...MODELS SHOW A SURGE OF
EASTERLY WINDS MOVING INTO THE EASTERN PLAINS. THEY GET INTO THE
EASTERN TWO-THIRDS OF THE PLAINS BY SATURDAY MORNING. ON SATURDAY
.MODELS SHOW THE EASTERLY UPSLOPE GETTING ACROSS ALL THE PLAINS
INTO THE LOWER FOOTHILLS. BY SATURDAY NIGHT...NORMAL WINDS
PATTERNS SHOULD RETURN. FOR MOISTURE...THERE IS QUITE A BIT ON
FRIDAY. IT`S FAIRLY DEEP OVER THE MOUNTAINS ON THE GFS IN THE
MORNING...BUT IN THE AFTERNOON ON THE NAM. BY AFTERNOON...THERE IS
QUITE A BIT OF MID AND UPPER LEVEL MOISTURE OVER THE PLAINS. THERE
IS NOT MUCH MOISTURE OVER THE MOUNTAINS FRIDAY NIGHT AND SATURDAY
MORNING...BUT MODELS DO SHOW STRATUS OVER ALL THE PLAINS. THE NAM
INCREASES MOISTURE FROM THE WEST AND DEEPENS IT SATURDAY AFTERNOON
AND NIGHT. THE GFS DOES NOT BRING THIS IN TO MOUNTAINS UNTIL LATER
SATURDAY NIGHT. BOTH KEEP THE LOW LEVEL MOISTURE OVER THE PLAINS
THE REST OF THE SATURDAY AND SATURDAY NIGHT. THE QPF FIELDS HAVE A
TAD OF MEASURABLE PRECIPITATION OVER THE MOUNTAINS FRIDAY MORNING
.THEN MORE BY AFTERNOON AS WELL AS SOME OVER THE NORTHERN BORDER
OF THE CWA. THIS CONTINUES FRIDAY NIGHT. ON SATURDAY...THERE IS A
TAD OF MEASURABLE PRECIPITATION OVER ALL THE PLAINS...BUT NOTHING
FOR THE MOUNTAINS. BY SATURDAY NIGHT...THERE IS A BIT OVER THE
MOUNTAINS...WITH THE PLAINS DRY. SO FOR POPS...NOT TO EXCITING.
MOISTURE IS PROBLEMATIC BETWEEN MODELS. THE SYNOPTIC SCALE ENERGY
IS WEAK AND DOESN`T KICK IN UNTIL SATURDAY AFTERNOON....AND THE
MOUNTAINS HAVE NEUTRAL OR WARM-AIR ADVECTION MUCH OF THE TIME. ALSO
IN THE MOUNTAINS...OROGRAPHICS ARE NOT GOOD. SO WILL GO WITH
20-30%S IN THE MOUNTAINS ON FRIDAY AND FRIDAY NIGHT...AND THEN AGAIN
SATURDAY AFTERNOON AND NIGHT. WILL GO WITH 20% POPS OVER THE
NORTHERN PLAINS FRIDAY NIGHT INTO SATURDAY...THEN OVER ALL THE
PLAINS SATURDAY AFTERNOON AND NIGHT. FOR TEMPERATURES...FRIDAY`S
HIGHS ARE A TAD WARMER THAN TODAY`S...EXCEPT OVER THE NORTHEAST
CORNER WITH THE NEW AIRMASS IN PLACE. THIS COOLER AIR WILL LIKELY
MAKE IT ACROSS ALL THE PLAINS ON FRIDAY. ALSO...REAL TEMPERATURE
DATA OVER THE LAST FEW DAYS HAS BEEN INFLUENCED BY THE SNOW FIELD IN
PLACE. SATURDAY`S HIGHS ARE 3-4 C COOLER FOR THE PLAINS AND
FOOTHILLS...BUT A BIT WARMER OVER THE MOUNTAINS. FOR THE LATER
DAYS...SUNDAY THROUGH WEDNESDAY...MODELS HAVE A WEAK UPPER TROUGH
MOVE ACROSS ON SUNDAY...THEN UPPER RIDGING ON MONDAY INTO TUESDAY.
BY LATER TUESDAY NIGHT AND WEDNESDAY...ANOTHER UPPER TROUGH MOVES
IN. BOTH THE ECMWF AND GFS SHOW SOME VERSION OF THIS...BUT ITS
PRETTY CONVOLUTED. MOISTURE IS NOT GREAT SUNDAY THROUGH TUESDAY.
ON WEDNESDAY IT IS A BIT BETTER...ESPECIALLY ON THE GFS...BUT NOT
GREAT AND NOT CONSISTENT. I DOUBT TEMPERATURES WILL WARM TO
SEASONAL NUMBERS ANY OF THE FOUR DAYS.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. SOME
UNCERTAINTY ON WIND DIRECTION AGAIN THIS AFTERNOON. IT NOW LOOKS
LIKE WE SHOULD HAVE NORTH TO NORTHWEST WINDS THIS AFTERNOON...
POSSIBLY AS MUCH AS 10 KNOTS AT KDEN...THEN BACK TO S/W DRAINAGE
WINDS THIS EVENING. THERE IS A CHANCE THAT WINDS WILL JUST BECOME
LIGHT AND VARIABLE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1114 AM MST THU FEB 9 2012
.UPDATE...
HAVE UPDATED POPS AND CLOUD COVER OVER THE NWRN PLATEAU/MTN
COUNTRY. THIS AS A CHANNELED VORT PATTERN AND EXISTING MOISTURE
COMBINE TO PRODUCE LIGHT SNOWFALL IN THAT AREA.
&&
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
AREAS OF FOG WILL CONTINUE TO RESTRICT VSBY TO MVFR CONDITIONS
ALONG THE LOWER I-70 CORRIDOR UNTIL AROUND NOON...WHILE LIGHT SNOW
CONTINUES AT THE HIGHER ELEVATION TAF SITES. FOR THIS AFTERNOON A
MOIST NORTHWESTERLY FLOW WILL BRING INSTABILITY SHOWERS TO THE
NORTHWEST PLATEAU AND MTN COUNTRY WITH MVFR CONDITIONS EXPECTED THROUGH
THIS AFTERNOON. VFR CONDITIONS ARE ANTICIPATED TO RETURN TONIGHT...
ALTHOUGH PATCHY LOCALIZED FOG MAY REDEVELOP AFTER MIDNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....MC
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1056 AM MST THU FEB 9 2012
.UPDATE...SHORTWAVE CURRENTLY PASSING ACROSS AREA...STILL QUITE A
BIT OF CLOUDS ACROSS MUCH OF CFWA. WEB CAMS AND RADAR LOOPS
SHOWING PERSISTANT LIGHT SNOW OVER THE MOUNTAINS...MAINLY ALONG
THE CONTINENTAL DIVIDE. DESPITE SUBSIDENCE THIS AFTERNOON BEHIND
EXITING SHORTWAVE...BOTH NAM AND RUC STILL KEEP QUITE A BIT OF
CLOUD OVER THE MOUNTAINS...ALONG WITH LIGHT QPF/SNOW AMOUNTS ALONG
THE DIVIDE. BASED ON THE CURRENT TRENDS...WILL NEED TO KEEP A
CHANCE OF SNOW OVER THE HIGHER PEAKS THROUGH MUCH OF THE
AFTERNOON. OTHERWISE...TREND TOWARD DECREASING CLOUDS STILL
LOOKING ON TRACK FOR NOW. REST OF FORECAST TRENDS ALSO ON TRACK.
&&
.AVIATION...CURRENT TAF TRENDS SEEM ON TRACK...DID KEEP THE BROKEN
MID LEVEL A BIT LONGER. LATEST NAM AND GFS GUIDANCE SHOWING A
BROKEN 6000-7000 AGL DECK THROUGH 21Z. NOT SURE IF THIS WILL PAN
OUT BASED ON AREA OBSERVATIONS. A BIT OF STRATUS TOWARDS CASPER
WITH SOME LIGHT SNOW...DON`T THINK IT WILL PUSH INTO COLORADO ANY
TIME SOON.
&&
.PREV DISCUSSION... /ISSUED 400 AM MST THU FEB 9 2012/
SHORT TERM...WEAK SHORTWAVE MOVING ACROSS COLORADO THIS MORNING.
MOISTURE WILL BE DIMINISHING FROM THE NORTHWEST THOUGH A FEW SNOW
SHOWERS MAY HANG ON INTO THE AFTERNOON IN THE HIGH MOUNTAINS. NOT A
LOT OF TEMPERATURE ADVECTION WITH THIS TROUGH...A WARMER START TO
THE DAY AND A BIT MORE MIXING AS A RESULT...SO WILL TRY AGAIN FOR A
WARMER DAY OVER THE PLAINS. WE WILL LIKELY SEE THE SAME TEMPERATURE
PATTERN HOWEVER...JUST NOT AS EXTREME. STILL NEED TO DROP FORECAST
HIGHS ON THE PLAINS...UNDERCUTTING MOS GUIDANCE IN MOST AREAS DUE TO
THE SNOW COVER. MOSTLY CLEAR SKIES THIS EVENING THEN SOME INCREASE
IN CLOUD COVER POSSIBLE AGAIN TOWARD MORNING. COOLED LOWS IN THE
MOUNTAIN VALLEYS...BUT NOT AS MUCH AS GUIDANCE SINCE THERE IS STILL
SOME MOISTURE AND PROBABLY SOME CLOUD COVER AGAIN TOWARD MORNING.
LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED FRIDAY INTO FRIDAY
NIGHT. THEN AN UPPER RIDGE MOVES ACROSS THROUGH SATURDAY. ZONAL
FLOW EARLY ON SATURDAY BECOMES WEST-SOUTHWESTERLY BY SATURDAY
AFTERNOON...THEN SOUTHWESTERLY SATURDAY NIGHT. THE SYNOPTIC SCALE
ENERGY IS BENIGN FRIDAY INTO MID DAY SATURDAY...THEN WEAK UPWARD
VERTICAL VELOCITY IS PROGGED BY AFTERNOON THROUGH SATURDAY NIGHT.
THE LOW LEVEL PRESSURE AND WIND FIELDS ELUDE TO NORMAL DIURNAL WIND
PATTERNS FOR FRIDAY. BY FRIDAY NIGHT...MODELS SHOW A SURGE OF
EASTERLY WINDS MOVING INTO THE EASTERN PLAINS. THEY GET INTO THE
EASTERN TWO-THIRDS OF THE PLAINS BY SATURDAY MORNING. ON SATURDAY
..MODELS SHOW THE EASTERLY UPSLOPE GETTING ACROSS ALL THE PLAINS
INTO THE LOWER FOOTHILLS. BY SATURDAY NIGHT...NORMAL WINDS
PATTERNS SHOULD RETURN. FOR MOISTURE...THERE IS QUITE A BIT ON
FRIDAY. IT`S FAIRLY DEEP OVER THE MOUNTAINS ON THE GFS IN THE
MORNING...BUT IN THE AFTERNOON ON THE NAM. BY AFTERNOON...THERE IS
QUITE A BIT OF MID AND UPPER LEVEL MOISTURE OVER THE PLAINS. THERE
IS NOT MUCH MOISTURE OVER THE MOUNTAINS FRIDAY NIGHT AND SATURDAY
MORNING...BUT MODELS DO SHOW STRATUS OVER ALL THE PLAINS. THE NAM
INCREASES MOISTURE FROM THE WEST AND DEEPENS IT SATURDAY AFTERNOON
AND NIGHT. THE GFS DOES NOT BRING THIS IN TO MOUNTAINS UNTIL LATER
SATURDAY NIGHT. BOTH KEEP THE LOW LEVEL MOISTURE OVER THE PLAINS
THE REST OF THE SATURDAY AND SATURDAY NIGHT. THE QPF FIELDS HAVE A
TAD OF MEASURABLE PRECIPITATION OVER THE MOUNTAINS FRIDAY MORNING
..THEN MORE BY AFTERNOON AS WELL AS SOME OVER THE NORTHERN BORDER
OF THE CWA. THIS CONTINUES FRIDAY NIGHT. ON SATURDAY...THERE IS A
TAD OF MEASURABLE PRECIPITATION OVER ALL THE PLAINS...BUT NOTHING
FOR THE MOUNTAINS. BY SATURDAY NIGHT...THERE IS A BIT OVER THE
MOUNTAINS...WITH THE PLAINS DRY. SO FOR POPS...NOT TO EXCITING.
MOISTURE IS PROBLEMATIC BETWEEN MODELS. THE SYNOPTIC SCALE ENERGY
IS WEAK AND DOESN`T KICK IN UNTIL SATURDAY AFTERNOON....AND THE
MOUNTAINS HAVE NEUTRAL OR WARM-AIR ADVECTION MUCH OF THE TIME. ALSO
IN THE MOUNTAINS...OROGRAPHICS ARE NOT GOOD. SO WILL GO WITH
20-30%S IN THE MOUNTAINS ON FRIDAY AND FRIDAY NIGHT...AND THEN AGAIN
SATURDAY AFTERNOON AND NIGHT. WILL GO WITH 20% POPS OVER THE
NORTHERN PLAINS FRIDAY NIGHT INTO SATURDAY...THEN OVER ALL THE
PLAINS SATURDAY AFTERNOON AND NIGHT. FOR TEMPERATURES...FRIDAY`S
HIGHS ARE A TAD WARMER THAN TODAY`S...EXCEPT OVER THE NORTHEAST
CORNER WITH THE NEW AIRMASS IN PLACE. THIS COOLER AIR WILL LIKELY
MAKE IT ACROSS ALL THE PLAINS ON FRIDAY. ALSO...REAL TEMPERATURE
DATA OVER THE LAST FEW DAYS HAS BEEN INFLUENCED BY THE SNOW FIELD IN
PLACE. SATURDAY`S HIGHS ARE 3-4 C COOLER FOR THE PLAINS AND
FOOTHILLS...BUT A BIT WARMER OVER THE MOUNTAINS. FOR THE LATER
DAYS...SUNDAY THROUGH WEDNESDAY...MODELS HAVE A WEAK UPPER TROUGH
MOVE ACROSS ON SUNDAY...THEN UPPER RIDGING ON MONDAY INTO TUESDAY.
BY LATER TUESDAY NIGHT AND WEDNESDAY...ANOTHER UPPER TROUGH MOVES
IN. BOTH THE ECMWF AND GFS SHOW SOME VERSION OF THIS...BUT ITS
PRETTY CONVOLUTED. MOISTURE IS NOT GREAT SUNDAY THROUGH TUESDAY.
ON WEDNESDAY IT IS A BIT BETTER...ESPECIALLY ON THE GFS...BUT NOT
GREAT AND NOT CONSISTENT. I DOUBT TEMPERATURES WILL WARM TO
SEASONAL NUMBERS ANY OF THE FOUR DAYS.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. SOME
UNCERTAINTY ON WIND DIRECTION AGAIN THIS AFTERNOON. IT NOW LOOKS
LIKE WE SHOULD HAVE NORTH TO NORTHWEST WINDS THIS AFTERNOON...
POSSIBLY AS MUCH AS 10 KNOTS AT KDEN...THEN BACK TO S/W DRAINAGE
WINDS THIS EVENING. THERE IS A CHANCE THAT WINDS WILL JUST BECOME
LIGHT AND VARIABLE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
936 AM MST THU FEB 9 2012
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 18Z TAF ISSUANCE/...
AREAS OF FOG WILL CONTINUE TO RESTRICT VSBY TO MVFR CONDITIONS
ALONG THE LOWER I-70 CORRIDOR UNTIL AROUND NOON...WHILE LIGHT SNOW
CONTINUES AT THE HIGHER ELEVATION TAF SITES. FOR THIS AFTERNOON A
MOIST NORTHWESTERLY FLOW WILL BRING INSTABILITY SHOWERS TO THE
NORTHWEST PLATEAU AND MTN COUNTRY WITH MVFR CONDITIONS EXPECTED THROUGH
THIS AFTERNOON. VFR CONDITIONS ARE ANTICIPATED TO RETURN TONIGHT...
ALTHOUGH PATCHY LOCALIZED FOG MAY REDEVELOP AFTER MIDNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....MC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
904 AM MST THU FEB 9 2012
.UPDATE...
SNOW HAS MOSTLY ENDED OVER THE GORGE AREA OF THE NORTHWESTERN SAN
JUAN MOUNTAINS...SO ALLOWED THE SNOW ADVISORY IN THAT AREA TO
EXPIRE AT 0900. IN THE WESTERN GRAND VALLEY VISIBILITIES CONTINUE
TO IMPROVE SO ALLOWED THE DENSE FOG ADVISORY TO EXPIRE AT 0900 IN
THAT AREA AS WELL.
&&
.SHORT TERM /REST OF TODAY THROUGH FRIDAY NIGHT/...
KGJT RAOB INDICATED THAT MOISTURE HAD ARRIVED AS ANTICIPATED
DOUBLING OVER THE PAST 24 HOURS REACHING ALMOST .40 OF AN INCH.
ALSO AS EXPECTED...THE PRECIPITATION EXPANDED OVER WESTERN COLORADO
DURING THE EVENING AND EARLY MORNING HOURS AS WATER VAPOR SHOWED A
DISTINCT SHORTWAVE DROPPING INTO EASTERN UTAH. SNOTELS OVER MOST
OF THE REGION SEEMED TO INDICATED THINKING THE PAST FEW DAYS OF A
LIGHT SNOWFALL EVENT IN THE 2 TO 5 INCH RANGE MOST PLACES...WITH A
FEW LOCALLY HIGHER AMOUNTS. ONE EXCEPTION AS NOTED IN EARLIER
DISCUSSION WAS IN ZONE 18 ALONG HIGHWAY 55O FROM THE GORGE UP TO
RED MOUNTAIN PASS WHERE 2 INCH SNOW RATES WERE REPORTED. KGJX VWP
SHOWED AN INCREASINGLY LIGHT NORTHERLY FLOW EARLY THIS MORNING AND
WITH THE MAIN VORT PASSING JUST TO THE EAST SNOWFALL PRODUCTION
WAS VERY EFFICIENT. THIS WAVE WILL BE PASSING AND THE OVERALL
ASCENT WILL BE DECREASING...BUT THE MOIST FAVORABLE FLOW UP THE
GORGE SHOULD KEEP ACCUMULATING SNOW POSSIBLE THROUGH AT LEAST MID
MORNING. IN THE WAKE OF THE WAVE MOVING INTO THE 4 CORNERS
REGION...THE LOSS OF HIGHER CLOUD COVER AND NEW SNOW COVER HAS
ALLOWED DENSE FOG TO FORM OVER THE WESTERN GRAND VALLEY AS HAVE
ISSUED AN ADVISORY TO COVER THIS THROUGH MID MORNING.
WATER VAPOR WOULD INDICATED THE BULK OF THE MOISTURE IS BEING SWEPT
EASTWARD THIS MORNING AND QG FIELDS SUGGEST SUBSIDENCE OR WEAKENING
ASCENT IS TAKING OVER AS WELL. THIS SHOULD LEAVE OROGRAPHICS AS THE
MAIN MODE FOR PRECIP PRODUCTION IN THE NORTHERLY FLOW. HOWEVER
SATELLITE PICS HINT THAT THE NEXT WAVE DROPPING INTO NORTHWEST
WYOMING IS STILL CAPABLE OF PRODUCING SOME LIFT...AND THE RUC QG
FIELD ARE TRENDING STRONGER WITH THE ASCENT OVER NORTHERN COLORADO
THROUGH NOON. THEREFORE HAVE KEPT POPS FAIRLY HIGH OVER THE NORTHERN
AND CENTRAL MOUNTAINS THIS MORNING...AS WELL AS PORTIONS OF THE SAN
JUAN MOUNTAINS MENTIONED ABOVE. THE NORTHWEST PLATEAU AND UPPER I-70
VALLEYS SHOULD ALSO SEE ENOUGH LIFT TO GET LIGHT SNOW THROUGH MID
MORNING. THIS AFTERNOON THE WYOMING WAVE LOOKS TO DRAG SOME MUCH
COOLER AIR OVER CENTRAL COLORADO SO DECIDED TO KEEP SCATTERED
SHOWERS MENTIONED IN THE MOUNTAINS DUE TO TH ADDED INSTABILITY.
ADDITIONAL SNOW ACCUMS SHOULD BE QUITE LIGHT WITH DRIER AIR WORKING
IN BEHIND THE WAVE AS WELL.
THE RADAR SHOULD QUIET DOWN AFTER SUNSET WITH RELAXING LAPSE RATES
AND A TEMPORARY LULL IN SHORT WAVE ENERGY MOVING THROUGH THE
NORTHWEST FLOW. ON FRIDAY THE AMPLIFIED RIDGE IN THE WEST WILL BEGIN
TO BE FLATTENED BY ENERGY EJECTING FROM AN EASTERN PAC LOW. SOME OF
THIS ENERGY WILL DROP OVER THE RIDGE AND SPILL INTO NORTHERN
COLORADO THROUGH THE DAY. THEREFORE WILL GO AHEAD AND INCREASE POPS
SLIGHTLY FRIDAY INTO FRIDAY NIGHT...WITH NEW SNOWFALL AMOUNTS
EXPECTED TO REMAIN BELOW MOUNTAIN ADVISORY CRITERIA.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD FEATURES A SIGNIFICANT SPLIT IN FLOW OVER
THE CONTINENT WITH A RIDGE OF HIGH PRESSURE OVER THE WESTERN
CANADIAN PROVINCES AND A TROUGH OVER THE SOUTHWESTERN U.S. MODELS
WERE SIMILAR IN CARRYING THE TROUGH ONTO THE CALIFORNIA COAST ON
SATURDAY PUMPING UP A SHORTWAVE RIDGE OVER THE FORECAST AREA. THOUGH
SOME MID-LEVEL MOISTURE ENTRAINED IN THE SOUTHWEST FLOW...CHANCES FOR
PRECIPITATION APPEARED LIMITED.
HOWEVER...PRECIPITATION CHANCES INCREASE GOING INTO THE LATTER PART
OF THE WEEKEND AS THE LOW PRESSURE TROUGH SWINGS ACROSS THE GREAT
BASIN SATURDAY NIGHT...THEN ACROSS EASTERN UTAH AND WESTERN
COLORADO ON SUNDAY. ECMWF SOLUTION CARRIES ENERGY A BIT FARTHER
SOUTH THAN THE GFS40...HOWEVER BOTH INDICATED SIGNIFICANT SNOWFALL
IS POSSIBLE WITH THIS SYSTEM AS SNOW LINGERS OVER THE MOUNTAINS
THROUGH SUNDAY NIGHT.
SNOWFALL CHANCES DECREASE MONDAY AS A SHORTWAVE RIDGE DEVELOPS AHEAD
OF THE NEXT LOW PRESSURE SYSTEM MOVING ONSHORE. MODELS DIVERGE WITH
THIS NEXT STORM WITH THE ECMWF AGAIN FARTHER SOUTH THAN THE GFS40.
REGARDLESS OF THEIR DIFFERENCES...BOTH MODELS INDICATED THAT
UNSETTLED CONDITIONS WILL REDEVELOP TUESDAY AND WILL PERSIST INTO
WEDNESDAY.
TEMPERATURES WILL BE WARMER THAN NORMAL SATURDAY AS WARM SOUTHWEST
FLOW DEVELOPS AHEAD OF THE SYSTEM WHICH WILL IMPACT THE REGION THIS
WEEKEND. HOWEVER...A COOLING TREND BEGINS SUNDAY AS YET ANOTHER
SYSTEM MOVES THROUGH THE AREA AS DESCRIBED ABOVE.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
EXPECT WIDESPREAD MVFR CIGS AND VSBY ALONG A KRKS-30W KGJT-35NW KCEZ-
30SW KPSO AS A FAST MOVING SHORTWAVE TROUGH CONTINUES TO IMPACT MUCH
OF COLORADO EARLY THIS MORNING. RESIDUAL LOW-LEVEL MOISTURE AND
CLEARING SKIES ON THE BACK SIDE OF THIS SYSTEM WILL RESULT IN AREAS
OF FOG ACROSS THE CENTRAL COLORADO VALLEYS INCLUDING KGJT...KRIL...
KMTJ AND KASE. PERIODS OF IFR/LIFR CONDITIONS ARE LIKELY AT TIMES.
MEANWHILE...LINGERING SNOW IN THE COLORADO MOUNTAINS WILL BRING
WIDESPREAD MOUNTAIN OBSCURATIONS THROUGH MIDDAY. CONDITIONS IMPROVE
FROM WEST TO EAST DURING THE AFTERNOON. MOUNTAINS SNOW WILL BECOME
SHOWERY AND SCATTERED IN COVERAGE. MEANWHILE...EXPECT VFR
CONDITIONS ACROSS ALL OF EASTERN UTAH AND THE SOUTHWEST CORNER OF
COLORADO TODAY.
SHOWERS DIMINISH SHORTLY AFTER SUNSET AND VFR CONDITIONS WILL BECOME
THE RULE OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...MC
LONG TERM....NL
AVIATION.....NL
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1128 AM EST THU FEB 9 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /REST OF TODAY/...
UPDATED TO SIGNIFICANTLY INCREASE CLOUD COVER AND AS A
RESULT...LOWER TEMPERATURES ACROSS THE BOARD ABOUT 2 TO 5 DEGREES.
PERSISTENT STRATUS DECK THAT WAS ORIGINALLY EXPECTED TO BEGIN
DISSIPATING WITH THE ENCROACHMENT OF DRIER HIGH PRESSURE...HAS
ACTUALLY EXPANDED ON ITS NORTHERN FRINGE THIS MORNING. ADDITIONAL
STRATUS TO THE WEST IS ALSO BUILDING TOWARD THE AREA FASTER THAN
EXPECTED.
THAT SAID...EDGES ARE THINNER AND TAKING ON A MORE DIURNAL
APPEARANCE ON SATELLITE...AND COUPLED WITH A SLOT OF CLEAR SKIES
TO THE WEST...MAY SEE CLEARING IN THE NORTHWEST AND FAR WESTERN
FRINGE OF THE FORECAST AREA LATER THIS AFTERNOON. HOWEVER MOST OF
THE AREA SHOULD REMAIN AT LEAST MOSTLY CLOUDY.
TEMPS HAVE OBVIOUSLY BEEN IMPACTED BY THIS...AND HOURLY NUMERICAL
GUIDANCE INDICATES AT LEAST A COUPLE DEGREE DECREASE IS IN ORDER.
DECREASED MORE SIGNIFICANTLY IN AREAS EXPECTED TO REMAIN CLOUDY.
ALSO INSERTED A FLURRIES MENTION AS A FEW FLAKES HAVE BEEN FLYING
AT INDY...AND A SPIT OF SNOW CANNOT BE RULED OUT THROUGH THE DAY.
HOWEVER...THIS LITERALLY AMOUNTS TO ONLY A FEW FLAKES AND ZERO
SIGNIFICANCE IS EXPECTED FROM THIS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
1620Z UPDATE...BASED ON LATEST SAGGING TRENDS HAVE HELD ONTO
STRATO CU DECK MUCH LONGER THAN ORIGINALLY ANTICIPATED...WITH AT
BEST IT BEGINNING TO MIX OUT LATE THIS AFTERNOON. PREVIOUS DISCS
FOLLOW.
1430Z TAF UPDATE...STRATO CU DECK APPEARS TO BE RIGHT ON TRACK TO
MIX OUT AROUND 16Z THIS AFTERNOON. MADE FEW OR MINOR CHANGES TO
TAFS ATTM. PREVIOUS DISCUSSION FOLLOWS...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...NIELD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1117 AM EST THU FEB 9 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
QUIET WEATHER CAN BE EXPECTED INTO FRIDAY. HOWEVER...THE WEATHER
PATTERN WILL CHANGE AS A BROAD UPPER LEVEL TROUGH TRACKS ACROSS
THE UPPER MIDWEST AND GREAT LAKES REGION. ITS ASSOCIATED COLD
FRONT WILL BRING A CHANCE OF SNOW TO CENTRAL INDIANA ON FRIDAY
ALONG WITH MUCH COLDER AIR. SNOW ACCUMULATIONS WILL BE NONE TO
MINIMAL...BUT FRIGID TEMPS WILL LINGER OVER THE AREA INTO MONDAY.
AFTER THAT...WINDS WILL BECOME SOUTHERLY AND ADVECT WARMER TEMPS
INTO CENTRAL INDIANA. AS A RESULT...WHEN THE NEXT DISTURBANCE
MOVES IN ON MONDAY...PRECIP WILL GENERALLY BE IN THE FORM OF A
RAIN/SNOW MIXTURE.
&&
.NEAR TERM /REST OF TODAY/...
UPDATED TO SIGNIFICANTLY INCREASE CLOUD COVER AND AS A
RESULT...LOWER TEMPERATURES ACROSS THE BOARD ABOUT 2 TO 5 DEGREES.
PERSISTENT STRATUS DECK THAT WAS ORIGINALLY EXPECTED TO BEGIN
DISSIPATING WITH THE ENCROACHMENT OF DRIER HIGH PRESSURE...HAS
ACTUALLY EXPANDED ON ITS NORTHERN FRINGE THIS MORNING. ADDITIONAL
STRATUS TO THE WEST IS ALSO BUILDING TOWARD THE AREA FASTER THAN
EXPECTED.
THAT SAID...EDGES ARE THINNER AND TAKING ON A MORE DIURNAL
APPEARANCE ON SATELLITE...AND COUPLED WITH A SLOT OF CLEAR SKIES
TO THE WEST...MAY SEE CLEARING IN THE NORTHWEST AND FAR WESTERN
FRINGE OF THE FORECAST AREA LATER THIS AFTERNOON. HOWEVER MOST OF
THE AREA SHOULD REMAIN AT LEAST MOSTLY CLOUDY.
TEMPS HAVE OBVIOUSLY BEEN IMPACTED BY THIS...AND HOURLY NUMERICAL
GUIDANCE INDICATES AT LEAST A COUPLE DEGREE DECREASE IS IN ORDER.
DECREASED MORE SIGNIFICANTLY IN AREAS EXPECTED TO REMAIN CLOUDY.
ALSO INSERTED A FLURRIES MENTION AS A FEW FLAKES HAVE BEEN FLYING
AT INDY...AND A SPIT OF SNOW CANNOT BE RULED OUT THROUGH THE DAY.
HOWEVER...THIS LITERALLY AMOUNTS TO ONLY A FEW FLAKES AND ZERO
SIGNIFICANCE IS EXPECTED FROM THIS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS PRECIP CHANCES ON
FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A BROAD UPPER LEVEL LOW.
ASSOCIATED COLD FRONT WILL APPROACH NORTHWEST INDIANA AROUND
FRIDAY 12Z. HELD OFF ON PRECIP UNTIL CLOSER TO THE FRI 18Z TIME
FRAME...WHICH MODEL BLEND IS INDICATING. SO...ONLY WENT WITH
SLIGHT CHANCE POPS ACROSS WESTERN 2/3 OF FORECAST AREA FROM FRI
12-18Z. TEMPS SHOULD STILL BE COOL ENOUGH AT THAT TIME FOR SNOW
OVER ALL OF FORECAST AREA EXCEPT THE SOUTHERN THIRD WHICH CAN
EXPECT A RAIN/SNOW MIXTURE. HOWEVER...AS TEMPS INCREASE FROM
DIURNAL HEATING DURING THE FRI 18-22Z TIME FRAME...THE RAIN/SNOW MIX
LINE WILL MOVE FURTHER NORTH...ENCOMPASSING ALL BUT THE NORTHERN
THIRD OF THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THIS ALSO
HAPPENS TO BE WHEN THE BULK OF THE MOISTURE SHOULD MOVE
THROUGH...SO THIS WILL CUT BACK ON CHANCES FOR SNOW ACCUMULATION.
AFTER THAT...TEMPS WILL QUICKLY PLUMMET BEHIND COLD FRONT...AND
PRECIP WILL TRANSITION BACK TO ALL SNOW ACROSS ENTIRE FORECAST
AREA FROM SAT 00Z ON. HOWEVER...AMOUNTS WILL BE LESS THAN A HALF
OF AN AS MOISTURE BECOMES MORE LIMITED.
HELD ONTO CHANCE POPS THROUGH FRIDAY NIGHT DUE TO ANY ADDITIONAL
FORCING WITH PASSAGE OF UPPER LEVEL LOW...BUT SNOW WILL BE OUT OF
THE AREA ENTIRELY BY SAT 12Z...AND THE REMAINDER OF SHORT TERM
PERIOD WILL BE DRY AND COLD AS HIGH PRESSURE RE-ESTABLISHES ITSELF
OVER CENTRAL INDIANA.
TEMPS...WENT WITH A BLEND EXCEPT FOR TOMORROW NIGHT...TRENDED
TOWARD THE WARMER NAM DUE TO MOSTLY CLOUDY SKIES. IN
ADDITION...TRENDED VERY LOW ON SATURDAY NIGHT WITH THE CLEAR SKIES
AND DEEP COLD POST FRONTAL AIR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
DRY YET CHILLY WEATHER WILL CONTINUE TO WRAP UP THE WEEKEND AS A
LARGE AREA OF HIGH PRESSURE BLANKETS THE OHIO VALLEY. BROAD
SUBSIDENCE WILL ENSURE MAINLY SUNNY SKIES WITH A SLOW RISE IN TEMPS
THROUGH MONDAY AS WARM ADVECTION COMMENCES. DESPITE THE
SUNSHINE...THICKNESSES SUPPORT HIGHS REMAINING IN THE UPPER 20S AND
LOWER 30S SUNDAY...WITH HIGHS MODERATING INTO THE MID AND UPPER 30S
FOR MONDAY AS THE HIGH SHIFTS EAST AND RETURN SOUTHERLY FLOW
DEVELOPS.
EXTENDED MODELS REMAIN LARGELY IN GOOD AGREEMENT ON THE ARRIVAL OF
AN UPPER LEVEL DISTURBANCE MONDAY NIGHT/TUESDAY WITH ONLY THE GGEM
LAGGING THE FEATURE DUE TO INCREASED PHASING ALOFT. HAVE LEANED
CLOSER TO ECMWF WHICH HAS REMAINED CONSISTENT OVER THE LAST FEW RUNS
IN LOWER LEVELS COOLING SUFFICIENTLY ENOUGH MONDAY NIGHT FOR PRECIP
TO FALL AS LIGHT SNOW. COULD SEE SOME RAIN MIX IN WITH THE SNOW OVER
FAR SOUTHERN PORTIONS OF THE FORECAST AREA...BUT UNCERTAINTY IN THAT
HAPPENING RIGHT NOW IS HIGH ENOUGH TO KEEP A MIX MENTION OUT OF THE
FORECAST UNTIL TUESDAY AS TEMPS WARM. WILL MAINTAIN CHANCE POPS
THROUGH THIS TIMEFRAME.
SOME TIMING DIFFERENCES DEVELOP FROM THIS POINT FORWARD AS OP GFS
AND ECMWF ARE HANDLING THE EJECTION OF ENERGY OUT OF THE DEVELOPING
PACIFIC COAST TROUGH IN DIFFERENT WAYS. GROWING CONFIDENCE IN HIGH
PRESSURE BRIEFLY REESTABLISHING OVER THE OHIO VALLEY TUESDAY NIGHT
AND WEDNESDAY BEHIND THE LEAD UPPER WAVE AND HAVE CUT ALLBLEND POPS
SUBSTANTIALLY AS A RESULT. THE ARRIVAL OF THE UPPER ENERGY FROM THE
WESTERN TROUGH WILL SPUR A SURFACE WAVE TRAVERSING THE OHIO VALLEY
LATE WEDNESDAY INTO THURSDAY. AT THIS POINT IN TIME...APPEARS LOW
LEVEL THICKNESSES AND SURFACE TEMPS WARM ENOUGH TO SUPPORT MAINLY
RAIN FOR MUCH OF THE FORECAST AREA. UNTIL EXTENDED GUIDANCE CAN COME
INTO ALIGNMENT WITH REGARDS TO TRACK AND TIMING OF THE LOW...WILL BE
DIFFICULT TO EMPLOY MUCH ADDITIONAL DETAIL. WILL CARRY CHANCE POPS
WEDNESDAY NIGHT AND THURSDAY WITH TEMPS LIKELY WARMING INTO THE 40S.
&&
.AVIATION /DISCUSSION FOR 091200Z TAF ISSUANCE/...
1430Z TAF UPDATE...STRATO CU DECK APPEARS TO BE RIGHT ON TRACK TO
MIX OUT AROUND 16Z THIS AFTERNOON. MADE FEW OR MINOR CHANGES TO
TAFS ATTM. PREVIOUS DISCUSSION FOLLOWS...
STUBBORN STRATOCU DECK HAS STOPPED ITS SOUTHWARD PROGRESS AND
ACTUALLY EVEN DRIFTED BACK NORTH A BIT OVER THE LAST FEW HOURS.
CEILINGS ARE HOVERING RIGHT AROUND 3KFT WITH OBS SHOWING SPORADIC
DROPS INTO MVFR CATEGORY. LOOKING AT RUC SOUNDINGS AND LOW LEVEL RH
PROGS...HAVE DELAYED CLEARING AT KHUF AND KIND UNTIL CLOSER TO
MIDDAY AND NOT UNTIL 18Z AT KBMG. WILL HAVE TO WATCH THIS MORNING
AT KLAF AS BACK EDGE OF THE CLOUD DECK MAY SLIP BACK ACROSS THE
TAF SITE FOR A SHORT PERIOD OF TIME.
SHOULD SEE LOWER CLOUDS FINALLY MIX OUT DURING THE AFTERNOON AS
WINDS BACK TO A W/SW DIRECTION. SKIES WILL STAY MAINLY CLEAR INTO
THE EVENING UNTIL A MORE SIGNIFICANT PUSH OF MOISTURE INTO THE
REGION LATE AHEAD OF AN APPROACHING COLD FRONT. WILL SEE VFR
STRATOCU REDEVELOP AFTER MIDNIGHT WITH CEILINGS AT 5-7KFT. WINDS
WILL BACK TO LIGHT S/SW TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...NIELD
SHORT TERM...TDUD
LONG TERM....RYAN
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
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..
&&
.AVIATION...
CONTINUED HEATING HAS ALLOWED CIGS TO BECOME VFR EXCEPT KDBQ WHICH
REMAINS MVFR. NO MODEL IS HANDLING THE LOW CLOUDS BUT PARTIAL
CLEARING SHOULD OCCUR 02Z-09Z/10 THAT SHOULD ALLOW ALL TAF SITES TO
BECOME VFR. POST FRONTAL MVFR CIGS BEHIND THE ARCTIC FRONT WILL MOVE
IN FROM THE NORTH 10Z-16Z/10 WITH FLURRIES POSSIBLE. SHSN ARE
EXPECTED TO DVLP AFT 15Z/10 AS THE ATMOSPHERE BECOMES UNSTABLE.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
08/NICHOLS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1130 AM CST THU FEB 9 2012
.AVIATION...
DAYTIME HEATING IS ALLOWING THE CLOUD BASES TO SLOWLY RISE. MVFR
CONDITIONS ARE AT KCID AND WILL BE AT KDBQ SHORTLY. KMLI/KBRL WILL
START OUT WITH VFR CIGS BUT KMLI MAY GO TO VFR AROUND SUNSET.
BASED ON EXTRAPOLATION AND SOME INPUTS FROM THE MODELS...VFR
CONDITIONS SHOULD AGAIN DVLP 02Z/10 TO 09Z/10 AT ALL TAF SITES.
ARCTIC FRONTAL PASSAGE TO OCCUR 10Z/10 TO 15Z/10 WITH WINDS
INCREASING AFT 14Z/10. POST FRONTAL STRATUS WILL BRING MVFR CIGS
BACK INTO EACH TAF SITE 12Z/10 TO 18Z/10.
..08..
&&
.PREV DISCUSSION... /ISSUED 1024 AM CST THU FEB 9 2012/
UPDATE...
THE LOW CLOUDS CONTINUE TO ADVECT INTO THE CWFA AND ARE EITHER AT
OR APPROACHING THE MISSISSIPPI RIVER. ONCE AGAIN NO MODEL IS
HANDLING THESE CLOUDS. THE 12Z WRF HAS A VAGUE IDEA AND THE RUC
TRENDS ALSO HAVE A VAGUE IDEA. PER THESE MODELS CLOUDS SHOULD BE
AROUND FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING
HOURS. THERE ARE QUESTIONS AS TO HOW MUCH CLEARING WILL OCCUR
TONIGHT AHEAD OF THE APPROACHING ARCTIC FRONT.
IF CURRENT CLOUD TRENDS HOLD...THE HWY 20 CORRIDOR MAY SEE
SUNSHINE AGAIN DURING THE AFTERNOON HOURS. HOWEVER...THE RUC IS
SUGGESTING THAT LOW LEVEL LAPSE RATES WILL BECOME QUITE STEEP
DURING THE AFTERNOON WHICH MAY PROMOTE CLOUD DEVELOPMENT IN THE
CURRENT CLEAR AREA OF NORTH CENTRAL IOWA. ADDITIONALLY...THE RUC
IS INDICATING WEAK F VECTOR CONVERGENCE WITH A SMALL DROP IN
CONDENSATION PRESSURE DEFICITS WITH NEUTRAL OR VERY WEAK FORCING.
IF LAPSE RATES DO STEEPEN AS SUGGESTED...SOME FLURRIES MAY NOT BE
OUT OF THE QUESTION THIS AFTERNOON.
MAX TEMPERATURES HAVE BE LOWERED A FEW DEGREES TO REFLECT THE
SLIGHTLY QUICKER ARRIVAL OF THE CLOUDS. AN UPDATE TO THE FCST
SHOULD BE AVAILABLE AROUND 1030 AM.
.08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1024 AM CST THU FEB 9 2012
.UPDATE...
THE LOW CLOUDS CONTINUE TO ADVECT INTO THE CWFA AND ARE EITHER AT
OR APPROACHING THE MISSISSIPPI RIVER. ONCE AGAIN NO MODEL IS
HANDLING THESE CLOUDS. THE 12Z WRF HAS A VAGUE IDEA AND THE RUC
TRENDS ALSO HAVE A VAGUE IDEA. PER THESE MODELS CLOUDS SHOULD BE
AROUND FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING
HOURS. THERE ARE QUESTIONS AS TO HOW MUCH CLEARING WILL OCCUR
TONIGHT AHEAD OF THE APPROACHING ARCTIC FRONT.
IF CURRENT CLOUD TRENDS HOLD...THE HWY 20 CORRIDOR MAY SEE
SUNSHINE AGAIN DURING THE AFTERNOON HOURS. HOWEVER...THE RUC IS
SUGGESTING THAT LOW LEVEL LAPSE RATES WILL BECOME QUITE STEEP
DURING THE AFTERNOON WHICH MAY PROMOTE CLOUD DEVELOPMENT IN THE
CURRENT CLEAR AREA OF NORTH CENTRAL IOWA. ADDITIONALLY...THE RUC
IS INDICATING WEAK F VECTOR CONVERGENCE WITH A SMALL DROP IN
CONDENSATION PRESSURE DEFICITS WITH NEUTRAL OR VERY WEAK FORCING.
IF LAPSE RATES DO STEEPEN AS SUGGESTED...SOME FLURRIES MAY NOT BE
OUT OF THE QUESTION THIS AFTERNOON.
MAX TEMPERATURES HAVE BE LOWERED A FEW DEGREES TO REFLECT THE
SLIGHTLY QUICKER ARRIVAL OF THE CLOUDS. AN UPDATE TO THE FCST
SHOULD BE AVAILABLE AROUND 1030 AM.
..08..
&&
.AVIATION...
MVFR CIGS CONTINUE TO MOVE EASTWARD ACROSS IOWA AND AHEAD OF THE
CURRENT TAFS. TAFS HAVE BEEN UPDATED TO REFLECT AN EARLIER
ARRIVAL TIME. CIGS MAY INITIALLY BE VFR BUT SHOULD QUICKLY DROP
INTO THE MVFR RANGE.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
241 PM CST THU FEB 9 2012
.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.
&&
.AVIATION.../18Z TAF ISSUANCE/
ARCTIC FRONT STILL LOOKS ON TRACK TO DROP SOUTH THROUGH THE AREA
THIS EVENING... BRINGING A PERIOD OF SOME MVFR CEILINGS WITH IT AS
IT DOES SO. GUSTY NORTH-NORTHWEST WINDS WILL ALSO DEVELOP BEHIND
THE FRONT FOR A TIME. BOTH THE GUSTY WINDS AND MVFR CEILINGS
SHOULD DEPART FAIRLY QUICKLY DURING THE DAY ON FRIDAY AS DRIER AIR
AND ANTICYCLONIC FLOW ASSOCIATED WITH THE SURFACE RIDGE WORK INTO
THE AREA. THE NAM APPEARS OVERLY PESSIMISTIC WITH ITS LOW LEVEL
RH/CLOUD FORECASTS... KEEPING BOUNDARY LAYER DEWPOINTS TOO HIGH IN
THE WAKE OF THE FRONT AND THEREBY CONTINUING TO PRODUCE SOME
CONVECTIVE COLD AIR STRATOCU FOR A GOOD 24 HOURS AFTER IT APPEARS
LIKELY BASED ON UPSTREAM OBS... THE GFS... AND OTHER GUIDANCE.
KEPT SOME CEILINGS AROUND A BIT LONGER THAN PREVIOUSLY
INDICATED... MAINLY IN LINE WITH GFS FORECAST MOISTURE PROFILES.
KMSP... TAF REFLECTS GENERAL FORECAST THINKING... ALTHOUGH THERE
IS SOME UNCERTAINTY IN HOW LONG MVFR CEILINGS WILL LINGER INTO THE
DAY ON FRIDAY. THINK THERE COULD BE AN INITIAL BATCH OF CEILINGS
AROUND 2K FT AGL... THEN A CHANGE TO SCT FOR A TIME BEFORE SOME
REDEVELOPMENT OF CEILINGS CLOSER TO 3K FT AGL AFTER 12Z. BUT...
FOR NOW... KEPT THINGS SIMPLE AND JUST INCLUDED A LONGER PERIOD OF
CEILINGS WITH IMPROVEMENT OVER TIME. SOME WIND GUSTS HIGHER THAN
SUGGESTED COULD ALSO OCCUR TONIGHT AFTER FROPA DEPENDING UPON HOW
DEEPLY WE MIX IN THE POST FRONTAL COLD ADVECTION AND PRESSURE RISE AREA.
//OUTLOOK FOR KMSP FOR FRIDAY NIGHT THROUGH TUESDAY...
FRIDAY NIGHT THROUGH SUNDAY...VFR CONDITIONS EXPECTED.
SUNDAY NIGHT...MVFR CEILINGS POSSIBLE LATE.
MONDAY AND MONDAY NIGHT...MVFR CEILINGS EXPECTED.
TUESDAY...MVFR CEILINGS POSSIBLE EARLY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/JVM
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1123 AM CST Thu Feb 9 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Widespread stratus once again in place early this morning, which has
held overnight temperatures on the warm side for locations beneath
this cloud deck. Outside of the stratus, temperatures have dropped
quite a bit with lows currently in the teens across northeast Missouri.
Similar to yesterday, believe the stratus will be slow to erode today
which is supported by the latest RUC condensation deficits and
various BUFR soundings. However, overall model performance has been
poor in handling the low level moisture over the past couple of days
so confidence is necessarily high.
Surface ridge will shift into the lower to mid Mississippi valley
today allowing low level winds to swing around to the southwest.
This will advect warmer temperatures into the area although lighter
speeds will prevent significant warming. Mixing to around H9-H85
should help break up clouds to some degree. However, given the
expectation of prolonged, at least broken cloud cover, knocked a few
degrees off of temperatures for this afternoon.
Advertised Hudson Bay low will settle southward through the end of
the week with pronounced short wave energy diving southward into the
central CONUS. Given the meridional nature of the upper height
pattern by the beginning of the weekend in response to amplified
ridging across the western US/Canada, expect a decent chunk of arctic
air to dislodge and plunge southward into the region. Expect the sfc
baroclinic boundary to slide through the area Friday morning with CAA
taking shape thereafter. The main story through the weekend will then
be the cold temperatures as most locations will not see readings
above the freezing mark for several days.
Deep eastern US upper troughing establishes by the middle of the
weekend with upper short wave ridging sliding overhead by Sunday. A
more progressive upper flow pattern then establishes across the
CONUS through the end of the weekend and through the first half of
next week. Models continue to be in good agreement with the timing
of the next progressive short wave trough to affect the area by
Sunday night and Monday. Given the run to run consistency, felt
comfortable continuing to raise POPS for this time period. There
still appears to be a decent shot at accumulating snowfall across
most of the forecast area as this system swings through. The main
limiting factor at this point appears to be the speed at which the
system progresses through the area. Nevertheless, many areas may
finally be in store for the first decent snowfall of the season.
There looks to be a short reprieve on Tuesday before the next system
in the progressive pattern affects the area by Wednesday. Models
have not displayed as good run to run consistency during this period
and will remain close to the consensus numbers to account.
Deroche
&&
.AVIATION...
For the 18Z TAF: Will go with a more pessimistic forecast than in
previous TAF as stratus should remain planted across the terminals.
Ceilings are expected to bounce between VFR and MVFR for much of the
first 12 hours of the taf as westerly flow continues over snowpack to
the west and northwest.
For tonight, arctic cold front will enter the CWA after 06z tonight,
with winds gradually switching to the northwest and then north by
12z. Ceilings should lower once again as the front approaches and may
lower more significantly behind the front. Will introduce mvfr CIGS
before daybreak, with SREF probabilities indicating the potential for
IFR cigs by 12z. Clouds should clear substantially late Friday
morning.
Dux
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1022 AM CST THU FEB 9 2012
.DISCUSSION...
MAIN CHALLENGE TODAY WILL BE THE PASSAGE OF THE COLD FRONT. WINDS
HAVE SWITCHED TO THE NORTH IN THE NORTHERN FA AS THE FRONT
APPEARS TO LIE ALONG A KROX-KGFK-CARRINGTON LINE. THIS FRONT WILL
DROP SOUTH THRU THE ENTIRE FA THRU THE DAY BRINGING GUSTY NORTH
WINDS IN ITS WAKE. TEMPS ARE ACTUALLY RUNNING FAIRLY MILD SO FAR
WITH TEMPS NEAR 20F IN THE NORTH WHERE THE WIND SWITCH HAS ALREADY
OCCURRED. SEEMS LIKE TEMPS ACTUALLY CLIMB AS THE WINDS GO TO THE
WEST SO MANY AREAS WILL BE MILD TODAY ESPECIALLY EARLY. KJMS AT
27F WITH WEST WINDS. THEREFORE NOTCHED TEMPS UP A LITTLE BIT TO
MATCH THE RUC WHICH SEEMS TO MATCH CURRENT CONDITIONS THE BEST.
LOOKS LIKE THE STRONGEST WINDS SHOULD BE BY EARLY TO MID AFTERNOON
THEN THEY WILL START DROPPING IN THE LATE AFTERNOON AND EARLY
EVENING.
&&
.AVIATION...
WINDS HAVE SWITCHED TO THE NORTH AT KDVL AND KGFK NOW AS THE COLD
FRONT HAS ARRIVED. KTVF SHOULD BE NEXT AND THEN KFAR/KBJI WILL
SWITCH IN A FEW HOURS. THERE ARE SOME LOWER CEILINGS COMING DOWN
WITH THE FRONT BUT THEY SHOULD NOT LAST FOR VERY LONG.
&&
.PREV DISCUSSION... /ISSUED 307 AM CST THU FEB 9 2012/
SHORT TERM...
WINDS TODAY AND TEMPERATURES THROUGHOUT THE PERIOD WILL BE THE
MAIN FORECAST CONCERNS FOR THE SHORT TERM.
WV LOOP AND UPPER AIR ANALYSIS SHOW A DECENT SHORTWAVE COMING DOWN
THE BACKSIDE OF THE POLAR VORTEX CENTERED OVER THE EAST SIDE OF
HUDSON BAY. HEIGHTS WILL FALL THROUGHOUT THE DAY TODAY AS THE
SHORTWAVE DIGS DOWN. THE COLD FRONT THAT THE SHORTWAVE WILL HELP
BRING DOWN IS CURRENTLY HALFWAY THROUGH MANITOBA AND SEEMS TO BE
ON TRACK FOR ENTERING OUR NORTHERN CWA LATE THIS MORNING AND
PUSHING THE REST OF THE WAY THROUGH OUR COUNTIES THIS AFTERNOON.
THINK THAT AT LEAST THE NORTHERN COUNTIES WILL SEE FALLING TEMPS
THIS AFTERNOON UNDER STRONG COLD AIR ADVECTION SO INCLUDED A NON-
DIURNAL TEMPERATURE CURVE. CANADIAN RADAR HAS A NARROW BAND OF
RETURNS...BUT NOTHING SEEMS TO BE REACHING THE GROUND AT THIS
POINT. WILL KEEP AN EYE ON IT IN CASE A FLURRY MENTION NEEDS TO BE
ADDED JUST BEFORE THE FORECAST GOES OUT.
WINDS BEHIND THE COLD FRONT WILL BECOME QUITE BREEZY. THERE WILL
BE SOME GOOD MIXING THIS AFTERNOON...BUT 925 AND 850MB WINDS ARE
ONLY AROUND 20 TO 30 KTS OR SO. COLD AIR ADVECTION IS
STRONG...BUT MODELS ARE ALL PRETTY CONSISTENT ON KEEPING THE
HIGHEST WIND SPEEDS TO OUR SOUTHWEST. THINK THAT WINDS WILL STAY
BELOW ADVISORY CRITERIA AT THIS POINT. WINDS WILL BEGIN TO FALL
OFF TONIGHT...BUT NOT A HUGE AMOUNT AND MAY STILL BE AROUND 10 KTS
BY DAYBREAK. WITH CLEARING SKIES AND THE COLD AIR
MASS AS WELL AS A BIT OF LINGERING SNOW COVER...TEMPERATURES WILL BE
WELL BELOW ZERO ACROSS THE NORTHERN 2/3RDS OF THE CWA. WIND CHILLS
ARE EXPECTED TO DROP BELOW -20...WITH SOME LOCATIONS IN THE NORTH
BELOW -30. WILL INCLUDE AN SPS AND MENTION IN THE HWO...BUT NO
HEADLINES AT THIS TIME.
THE COLD SFC HIGH WILL CONTINUE THROUGH THE DAY ON FRIDAY...AND
EVEN WITH SUNNY SKIES TEMPS WILL NOT WARM MUCH. KEPT HIGHS IN THE
SINGLE DIGITS. THE NORTH TO NORTHWESTERLY FLOW ALOFT WILL CONTINUE
THROUGH FRIDAY NIGHT AND SATURDAY...WITH THE SFC HIGH STILL
HANGING AROUND THE PLAINS. TEMPS WILL CONTINUE TO BE FAIRLY COOL
THROUGH SATURDAY. THE TROUGH MOVES OFF TO THE EAST SATURDAY NIGHT
AND SFC WINDS SHIFT TO THE WEST AND SOUTHWEST AS THE SFC HIGH
CENTER MOVES SOUTH. THINK THAT TEMPS SHOULD BEGIN TO MODERATE A
BIT BY SATURDAY NIGHT.
LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT
SUNDAY THROUGH MONDAY...A WEAK UPPER LOW WILL MOVE SLOWLY EASTWARD
FROM MT INTO THE EASTERN DAKOTAS. MOST PRECIPITATION WITH THIS WAVE
WILL BE ACROSS SOUTHERN MN INTO WESTERN WI...BUT WILL MAINTAIN
SLIGHT CHANCE POPS ACROSS THE FAR SOUTHEASTERN FORECAST AREA ON
MONDAY. THEREAFTER...FLOW ALOFT TURNS NORTHWESTERLY WITH A COUPLE OF
WEAK...ILL-TIMED SHORT-WAVES MOVING THROUGH THE REGION. AIR MASS IS
DRY AND WILL KEEP FORECAST PRECIPITATION-FREE. TEMPERATURES WILL
SLOWLY INCREASE EACH DAY INTO THE MIDDLE OF NEXT WEEK WITH HIGHS IN
THE 20S AND LOWS IN THE SINGLE DIGITS TO TEENS ABOVE ZERO.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1241 PM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE TODAY. WEAK SYSTEM WITH RAIN OR SNOW FRIDAY. ARCTIC
COLD FRONT FRIDAY NIGHT FOR COLDER SNOW SHOWERS SATURDAY. COLD
SUNDAY. ANOTHER SYSTEM MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...SATELLITE IMAGERY CONFIRMS 12Z MODEL DATA OF LOW
LEVEL MOISTURE/CLOUDS TRAPPED UNDER INVERSION...MAINLY SOUTH AND
WEST...WILL BE SLOW TO DISSIPATE THIS AFTERNOON. WILL UPDATE TO HOLD
CLOUDS LONGER INTO EARLY AFTERNOON AND LOWER HIGHS UNDER THE CLOUD
SHIELD A COUPLE OF DEGREES. NO PRECIP.
PREVIOUS DISCUSSION BELOW...
CONTENDING WITH LINGERING LOW STRATUS HERE ON THE GRAVEYARD
SHIFT. CLEARING HAS MADE IT JUST E OF OH RVR...WITH EXCEPTION OF
NE KY WHERE CLDS PERSIST. LLVL RH FIELDS OFF RUC SEEM TO HAVE A
GOOD HANDLE ON THINGS AND HAVE USED IT TO BASE SKY GRIDS THRU
EARLY MORNING. THIS ALLOWS DRY PUNCH TO PUSH CLEARING LINE FURTHER
E TO ABOUT I79 CORRIDOR BY 10Z. FROM THERE EXPECT CLDS OVER MTNS
TO DIS SPATE SHORTLY AFTER SUNRISE. THINK LOW CLDS WILL HANG TOUGH
ACROSS WESTERN LOWLANDS...NE KY...AND SW VA THRU LATE MORNING
BEFORE SCT OUT.
LEFT POPS UNCHANGED REST OF TONIGHT. ALSO LEFT THE PATCHY FRZDZ
ALONG WITH SHSN IN WX GRIDS ACROSS THE MTNS BEFORE ENDING BY 10Z.
SEEING KEKN REPORT UP FROM TIME TO TIME. HOWEVER...LOOKING AT
SOUNDINGS...SATURATION TO -10C SHOULD STILL SUPPORT ICE CRYSTALS.
TEMP WISE...SHOULD BE LOOKING AT SOMEWHAT OF A TEMP GRADIENT THIS
MORNING WITH SOME UPR TEENS SHOWING UP ACROSS SE OH WHERE A CLR
SKY WILL PREVAIL..WITH LOW TO MID 20S SHOWING UP CENTRAL/NORTHERN
LOWLANDS. ACROSS NE KY...SOUTHERN COAL FIELDS...SW VA WILL BE HARD
PRESSED TO FALL MUCH REMAINDER OF NIGHT GIVEN CLDS. CAA WILL ALLOW
NORTHERN MTNS TO DIP WELL INTO THE TEENS DESPITE LINGERING CLDS.
WEAK SFC HIGH CONTROLS WX FOR TDY WITH AREAS OF CIRRUS. MAY SEE
SOME LINGERING CU/STRATOCU CU ACROSS NE KY/WESTERN LOWLANDS FROM
RESIDUAL LLVL MOISTURE. TRIED TO GO A HAIR BLO GUIDANCE TDY FOR
HIGHS AND INCORPORATE LWR NUMBERS ACROSS AFOREMENTIONED AREAS THAT
HAVE TO CONTEND WITH SOME CLDS.
WEAK SFC HIGH SLIDES EAST OVERNIGHT AMID INCREASING SW FLOW ALOFT.
MID/HI CLDS INCREASE LATE FROM W AND S AHEAD OF NEXT SYS. TOOK A
BLEND OF GUIDANCE FOR LOWS TONIGHT WITH A NOD TOWARD MAV.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
FRIDAY FORECAST IS RATHER TRICKY. MODEL SOUNDINGS SHOW THAT ARRIVING
PRECIPITATION CAUSING THE COLUMN TO EVAPORATORY COOL INTO A SNOW
SOUNDING. CONCERNED HOWEVER ABOUT THE TIME OF DAY THAT SYSTEM IS
ARRIVING...DURING THE WARMEST PART OF THE DAY. ANY SUNSHINE FRIDAY
MORNING COULD HEAT THE BOUNDARY LAYER TOO MUCH. WILL GO WITH RAIN OR
SNOW FOR NOW.
ARCTIC COLD FRONT THEN ARRIVES FRIDAY NIGHT. SOME GOOD SNOW SHOWERS
CAN BE EXPECTED ALONG AND BEHIND THE ARCTIC FRONT...BUT TIMING IN
THE MODELS IS STILL A BIT UNCERTAIN. WILL INCREASE POPS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
SECONDARY OR REINFORCING COLD FRONT SWEEPS THROUGH NEW ENGLAND
SUNDAY BUT HAS LITTLE EFFECT ON CENTRAL APPALACHIANS AND MID OHIO
VALLEY. WITH THE COLD DAWN AND LIGHT WINDS...TRIED TO KEEP MAXIMUM
TEMPERATURES AT OR COLDER THAN 00Z MOS GUIDANCE AND HPC MEDIUM RANGE
GUIDANCE. CONSIDERING SATURDAY...COULD BE 2 STRAIGHT DAYS OF SUB
FREEZING TEMPERATURES. WE WERE EVEN A BIT SLOWER WARMING UP
MONDAY...BASED ON THE SLOWER 00Z ECMWF SOLUTION.
HIGH AND MID LEVEL MOISTURE INCREASES UP THE OHIO VALLEY MONDAY
NIGHT INTO TUESDAY...AS WE TRY TO SLOWLY MODIFY THE DRY ARCTIC AIR
NEAR THE SURFACE. WILL HAVE CHANCE POPS LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...WITH SLIGHTLY HIGHER POPS OVER NORTHERN COUNTIES
AS WEAKENING 500 MB TROF LIFTS NORTHEAST INTO THE LOWER GREAT LAKES.
MAIN DILEMMA IS WHAT HAPPENS LATE TUESDAY INTO WEDNESDAY...BETWEEN
500 MB DISTURBANCE. THOUGHT POPS WOULD LOWER TUESDAY NIGHT...BEFORE
INCREASING WEDNESDAY INTO WEDNESDAY NIGHT. HAVE ALL RAIN FOR DAY 7
SYSTEM. 00Z MODEL SOLUTIONS HAD HIGHER 500 MB HEIGHTS HOLDING OVER
THE SOUTHEAST STATES...WITH THE WEDNESDAY SYSTEM. HOWEVER...NEW 12Z
GFS SEEMS TO BE RUSHING THE DAY 7 SYSTEM THROUGH FASTER...WITH LOWER
HEIGHTS OVER THE SOUTHEAST. WILL NOT JUMP ON THE FASTER 12Z GFS NOW.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z THURSDAY THRU 18Z FRIDAY...
LOW LEVEL MOISTURE TRAPPED UNDER HIGH PRESSURE INVERSION. ANY
LINGERING MVFR CEILINGS WILL LIFT BY 00Z TO VFR...AND GENERALLY
DISSIPATE BY 04Z AS INVERSION WEAKENS AND SOME DRIER AIR MOVES IN.
SFC HIGH RETREATS TO E TONIGHT WITH SW FLOW ALOFT INCREASING AHEAD
OF NEXT WX SYS. MID/HI CLDS WILL BE ON THE INCREASE FROM S AND W BY
12Z FRI...BUT ANY MVFR CONDITIONS IN PRECIP WILL WAIT TIL AFTER 18Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CLEARING EARLY TONIGHT COULD VARY A
FEW HRS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H M M M M M H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z FRIDAY...
IFR POSSIBLE IN SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ/TAX
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1242 PM EST THU FEB 9 2012
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN COMMAND OVER THE REGION THROUGH FRIDAY.
A COLD FRONT WILL MOVE ACROSS THE REGION FRIDAY NIGHT THROUGH MID
DAY ON SATURDAY. THEN ANOTHER AREA OF HIGH PRESSURE WILL BUILD BACK
IN SATURDAY EVENING AND REMAIN INTO MONDAY. THE NEXT FRONT WILL
APPROACH THE AREA LATE ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1240 PM...STRATO-CU IS SLOWLY SPREADING ACROSS THE
UPSTATE...THOUGH IT/S TAKING LONGER THAN EXPECTED TO MOVE INTO THE
NC FOOTHILLS. THAT/S STILL EXPECTED TO HAPPEN AND INCREASING CLOUDS
HAVE BEEN RETAINED IN THE GRIDS. A BAND OF HIGH CLOUDS IS ALSO
ADDING TO THE OPAQUE SKY COVER OVER THE UPSTATE AND SRN NC PIEDMONT.
AS OF 945 AM...A NEW WRINKLE HAS BEEN ADDED TO THE FORECAST FOR TDA
AS CLOUDS HAVE STARTED TO DEVELOP EAST OF THE MTNS...FROM GREENVILLE
OVER TO GAFFNEY. THE LATEST RUC AND NAM RH FIELDS IMPLY THAT THESE
CLOUDS...UP AROUND 4KFT...WILL SPREAD SLOWLY TO THE NORTH THIS
MORNING AS WEAK LLVL WARM ADVECTION DEVELOPS OVER THE REGION. THE
CLOUDS MAY EVENTUALLY SPREAD ACROSS THE NC FOOTHILLS AND UP ALONG
THE E SLOPES OF THE BLUE RIDGE. AT LEAST THAT/S WHAT I/VE DONE IN
THE GRIDS. THE 12 UTC GSO SOUNDING SHOWED THE MOIST LAYER AND
STRONG SUBSIDENCE INVERSION THAT IS SERVING TO KEEP IT FROM MIXING
OUT. OTHERWISE...TWEAKED DEWPOINTS UP A LITTLE EARLY IN THE
DAY...THOUGH THEY SHOULD MIX OUT MORE IN THE AFTN. OF COURSE...IF
THE CLOUD COVER IS TOO WIDESPREAD...THEN TEMPS AND DEWPOINTS WILL
NEED TO BE ADJUSTED. THIS IS LIABLE TO MAKE CONDITIONS EVEN LESS
FAVORABLE FOR CONTROLLED BURNS OVER THE FOOTHILLS THIS AFTN.
AS OF 615 AM...CLOUDS REMAIN PARKED ALONG THE WESTERN MOUNTAINS IN
LINGERING...BUT DIMINISHING...NORTHWEST FLOW MOISTURE. STRATOCUMULUS
HAS ALSO MANAGED TO DEVELOP IN THE NRLY FLOW OVER THE NRN NC
FOOTHILLS AND PIEDMONT. SKY COVER HAS BEEN INCREASED ALONG AND NORTH
OF INTERSTATE 40...BUT THE CLOUDINESS SHOULD NOT MAKE MUCH OF A RUN
SOUTHWARD TOWARD CHARLOTTE THIS MORNING GIVEN THE LIGHT DOWNSLOPE
FLOW OFF THE MOUNTAINS AND THE DRYING PROFILES.
OTHERWISE...SFC HIGH PRES WILL BUILD IN FROM THE WEST TODAY UNDER
ZONAL FLOW ALOFT. LEE TROUGHING IS EXPECTED TO DEVELOP AT THE SFC
JUST E OF THE BLUE RIDGE TO GIVE WINDS A LIGHT SW FLOW BY THIS AFTN.
LITTLE MORE THAN SCATTERED CIRRUS IS EXPECTED ONCE THE NW FLOW
MOISTURE QUITS. MAX TEMPS WILL LIKELY BE A CATEGORY BELOW NORMAL
THIS AFTN DESPITE THE DECENT INSOLATION. MID AND HIGH CLOUDS MAY
THICKEN A LITTLE TONIGHT...BUT MINS SHOULD BE AT OR BELOW GUIDANCE
IN THIS COOL AND DRY AIRMASS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AT 3 AM EST THURSDAY...AN MEAN UPPER TROUGH WILL PERSIST OVER THE
EAST FROM FRIDAY THROUGH SATURDAY NIGHT. ON FRIDAY A SHORTWAVE
ROUNDING THIS TROUGH WILL MOVE FROM THE SOUTHERN PLAINS TO THE GULF
STATES. MEANWHILE...A COLD FRONT WILL FORM IN THE LEE OF THE
APPALACHIANS. MOISTURE ALONG THIS FRONT WILL SUPPORT THE DEVELOPMENT
OF PRECIPITATION...ESPECIALLY OVER THE MOUNTAINS WHERE A COLD NW
UPSLOPE FLOW WILL SET UP LATE IN THE DAY. THE NEW FRONT MOVES
RAPIDLY EAST FRIDAY NIGHT...DRYING THE LEE OF THE MOUNTAINS...BUT
MOISTURE REMAINS OVER THE NC MOUNTAINS. ANOTHER COLD FRONT ARRIVES
ON SATURDAY MORNING...ACCOMPANIED BY MUCH LESS MOISTURE THAN ITS
PREDECESSOR.
MODEL TIME HEIGHTS SUGGEST PRECIPITATION WILL BEGIN FRIDAY
EVENING...PERHAPS EXTENDING EAST OF THE BLUE RIDGE BRIEFLY. AS THE
FRONT MOVES EAST...PRECIPITATION WILL BE LEFT ALONG THE TN BORDER
INTO SATURDAY NIGHT. MODEL SOUNDINGS SUPPORT A RAIN OR SNOW
SCENARIO...WITH PLENTY OF MOISTURE PRESENT AT ICE NUCLEATION
TEMPERATURES AND NO WARM NOSE BENEATH. ONLY THE VALLEY FLOORS AND
THE FOOTHILLS CAN EXPECT RAIN EARLY FRIDAY EVENING...WITH SNOW
LEVELS RAPIDLY DROPPING TO VALLEY FLOORS LATE IN THE EVENING WHILE
PRECIPITATION ENDS IN THE FOOTHILLS. SNOW CONTINUES DOWN TO THE
VALLEY FLOORS ON SATURDAY...BUT WITH TIME THE EVENT WILL BECOME MORE
CONFINED TO THE TN BORDER REGION. AT THIS POINT IT APPEARS THAT
ACCUMULATIONS OF 1 TO 2 INCHES MAY BE POSSIBLE ALONG THE TN
BORDER...WITH HALF INCH AMOUNTS AT HIGHER ELEVATIONS ALONG THE BLUE
RIDGE.
TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL ON FRIDAY AND FRIDAY
NIGHT...FALLING TO A FEW DEGREES BELOW NORMAL ON SATURDAY...AND
ALMOST 10 DEGREES BELOW NORMAL ON SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 200 AM THURSDAY...THE MEDIUM RANGE FORECAST PICKS UP AT 12Z
ON SUNDAY WITH A DEEP UPPER TROUGH AXIS MOVING OFF THE ATLANTIC AND
A BROAD UPPER RIDGING PRESENT OVER THE CENTRAL CONUS. THE LATEST
MODELS ARE IN GOOD AGREEMENT WITH AN UPPER LVL RIDGE OF HIGH
PRESSURE BUILDING OVER THE EASTERN CONUS THROUGH MONDAY BEFORE A
SHORTWAVE SWINGS ACROSS THE CAROLINAS MONDAY NIGHT INTO TUESDAY
MORNING. ANOTHER UPPER LEVEL RIDGE OF HIGH PRESSURE IS FORECAST TO
BUILD ACROSS THE EASTERN STATES THROUGH LATE WEDNESDAY AND A MOIST
SOUTHWESTERLY FLOW WILL DEVELOP AHEAD OF A LOW PRESSURE SYSTEM
APPROACHING FROM THE WEST THURSDAY.
AT THE SFC...DRY WEATHER WITH COOLER TEMPERATURES ARE EXPECTED OVER
THE REGION AS A BROAD SURFACE HIGH BUILDS ACROSS THE EASTERN STATES
SUNDAY INTO MONDAY. THE LATEST 00Z GFS AND THE ECMWF SHOW BETTER
CONSISTENCY WITH THE TIMING OF A WEAK UPPER LEVEL SHORTWAVE SWINGING
ACROSS OUR CWFA BETWEEN 12Z AND 18Z TUESDAY. AS THICKNESS VALUES
DECREASE QUIT A BIT IN RESPONSE TO THE SHORTWAVE PASSAGE...OVERNIGHT
TEMPERATURES WILL BE COLD ENOUGH FOR WINTRY TYPE PCPN ACROSS MUCH OF
THE REGION. THEREFORE...I KEPT AT LEAST SLIGHT CHANCE POPS IN FOR
SNOW OVER THE MOUNTAINS/FOOTHILLS WITH RAIN SNOW MIX OVER THE LOWER
PIEDMONT AREA THROUGH TUESDAY MORNING. ANY WINTRY PCPN WILL SWITCH
TO RAIN SHOWERS AFTER SUNRISE AS TEMPERATURES RISE ABOVE FREEZING
LVL. ANOTHER SURFACE HIGH WILL BUILD INTO THE REGION FOR DRY
CONDITIONS WITH MODERATING TEMPERATURES TUESDAY AFTERNOON INTO
WEDNESDAY. THURSDAY...MOIST SOUTHWESTERLY FLOW WILL DEVELOP OVER THE
REGION AHEAD OF A LOW PRESSURE SYSTEM APPROACHING FROM THE
MISSISSIPPI VALLEYS. INCREASING MOISTURE ALOFT WITH ISENTROPIC
LIFTING WILL GENERATE LIGHT PCPN OVER MUCH THE REGION BY THURSDAY
AND WILL BECOME MORE ACTIVE FRIDAY AS THE LOW ASSOCIATED WITH A COLD
FRONT CROSSES THE CAROLINAS. TEMPERATURES WILL REMAIN 7-10 DEGREES
BELOW NORMALS SUNDAY AND MONDAY...THEN STEADILY WARM THROUGH MID
WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...A STRATO-CU DECK WILL DEVELOP WEST OF THE AIRFIELD THIS
AFTN. FEW-SCT CLOUDS UP AROUND 4500 FEET WILL AFFECT THE AIRFIELD AT
TIMES...BUT I DON/T THINK A DECK WILL DEVELOP THAT FAR EAST. WINDS
WILL BE LIGHT AND VARIABLE FOR A WHILE EARLY THIS AFTN...BECOMING
LIGHT OUT OF THE SOUTH BY MID AFTN. A LIGHT SLY COMPONENT TO THE
FLOW SHOULD THEN CONTINUE FOR THE REST OF THE TAF PERIOD.
AT HKY...A STRATO-CU DECK UP AROUND 4500 FEET IS EXPECTED TO DEVELOP
AT THE AIRFIELD A LITTLE LATER THIS AFTN...THEN LAST WELL INTO THE
EVENING HOURS. WINDS WILL BE LIGHT OUT OF THE SOUTH THROUGH THE
VALID PERIOD OF THE TAF.
AT KAVL...LIGHT NLY FLOW EXPECTED THROUGH TONIGHT. NO LOW CIG OR
VSBYS PROBLEMS EXPECTED WITH A DRY AIRMASS OVER THE REGION.
HOWEVER...A DECK UP AROUND 4500 FEET COULD AFFECT THE AIRFIELD LATER
IN THE AFTN. CONFIDENCE IS TOO LOW TO INCLUDE THIS IN THE TAF.
UPSTATE SITES...SCT-BKN CIGS UP AROUND 4000-4500 FEET WILL GRADUALLY
LIFT NORTH OF THE REGION BY LATE AFTN. WINDS WILL BE LIGHT AND
VARIABLE...GRADUALLY BECOMING LIGHT OUT OF THE SOUTH. A DECK UP
AROUND 120KFT IS EXPECTED TO MOVE IN AFTER SUNRISE TMRW.
OUTLOOK...A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON FRIDAY
AND MOVE EAST OF THE REGION ON SATURDAY. THE BEST CHANCE OF
RESTRICTIONS WILL BE AT KAVL WITH FROPA AND JUST BEHIND IT EARLY
SATURDAY. DRY HIGH PRES WILL RETURN SUNDAY THROUGH MONDAY.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.FIRE WEATHER...
A CAUTIONARY NOTE FOR AGENCIES DOING CONTROLLED BURNS ACROSS THE
NORTH CAROLINA FOOTHILLS AND BLUE RIDGE TODAY. IF THE CLOUD COVER
THAT HAS STARTED TO DEVELOP OVER THE UPSTATE SPREADS NORTHWARD...AS
THE MODELS ARE ADVERTISING...TEMPERATURES WILL BE SLOWER TO
RISE...MIXING HEIGHTS WILL BE LOWER AND TRANSPORT WINDS WILL BE EVEN
LIGHTER THAN THE CURRENT FORECAST. PRESENT INDICATIONS ARE THAT THIS
WILL HAPPEN. IF YOU ARE ON THE FENCE ABOUT BURNING...IT/S BEST TO
HOLD OFF FOR TODAY.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JOH
AVIATION...MCAVOY
FIRE WEATHER...MCAVOY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
131 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.
WILL LET WIND ADVISORY EXPIRE AS PLANNED AT 00Z. STRONG PRESSURE
RISES AND COLD ADVECTION SHOULD KEEP THE WINDS GOING UNTIL THEN.
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...18Z TAFS UPDATE
STRONG NORTHWEST WINDS WILL SUBSIDE THROUGH THIS EVENING. MVFR CIGS
WILL SLIDE SOUTHWARD ACROSS NORTHWEST AND CENTRAL SOUTH DAKOTA THIS
EVENING...AND INTO WESTERN SOUTH DAKOTA AFTER 06Z. LIGHT SNOW IS
ALSO EXPECTED TO DEVELOP ACROSS PARTS OF NORTHEAST 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...WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR BUTTE-HAAKON-
HARDING-NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-
PERKINS-RAPID CITY-SOUTHERN MEADE CO PLAINS-
STURGIS/PIEDMONT FOOT HILLS-ZIEBACH.
WY...NONE.
&&
$$
SHORT TERM...BUNKERS
LONG TERM....CALDERON
AVIATION...CALDERON
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
215 PM CST THU FEB 9 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
215 PM CST THU FEB 9 2012
MAIN FORECAST CONTINUES TO BE FOCUSED ON ARCTIC FRONTAL PASSAGE
TONIGHT AND ASSOCIATED SNOW SHOWER/FLURRY ACTIVITY INTO FRIDAY.
COLDER AIR MASS THROUGH THIS WEEKEND ALONG WITH WIND EXPECTED TO
PRODUCE SOME CHILLIER THAN NORMAL TEMPERATURES AND VERY COLD WIND
CHILLS...ESPECIALLY ON SATURDAY MORNING.
CURRENT SURFACE MAP THIS AFTERNOON HAS THE ARCTIC FRONTAL BOUNDARY
OOZING SOUTHWARD ACROSS NORTHERN MN/ND. VISIBLE SATELLITE SHOWING A
PATCH OF CUMULUS/STRATOCUMULUS ACROSS MOST OF NORTHEAST IA AND
PORTIONS OF SOUTHEAST MN INTO FAR SOUTHWEST WI. OTHERWISE...
SOUTHWEST WINDS AHEAD OF THIS FRONTAL BOUNDARY WAS PRODUCING
TEMPERATURES IN THE UPPER 20S TO LOWER 30S ACROSS THE FORECAST AREA.
HOWEVER...WIND CHILLS WERE MAKING IT FEEL MORE LIKE THE TEENS AND
20S.
09.12Z MODELS IN GOOD AGREEMENT THROUGH THE SHORT TERM.
WATER VAPOR IMAGERY/RUC ANALYSIS SHOWING A FAIRLY STRONG MID-LEVEL
SHORTWAVE TROUGH ROTATING SOUTHEASTWARD THROUGH
ONTARIO/MANITOBA/SASKATCHEWAN THIS AFTERNOON. THIS WILL DRIVE THE
ARCTIC FRONT THROUGH THE AREA OVERNIGHT...EXITING SOUTH OF THE AREA
BY DAYBREAK. MODELS CONTINUE TO SHOW RATHER VIGOROUS FORCING WITH
THE FRONT WITH GOOD 850-300MB PV-ADVECTION/STEEPENING LOW LEVEL
0-1KM LAPSE RATES FOR SCATTERED SNOW SHOWERS. HIGHEST PROBABILITIES
FOR THE SNOW SHOWER ACTIVITY APPEARS TO ALONG AND NORTH OF THE I-94
CORRIDOR AFTER MIDNIGHT WITH FLURRY ACTIVITY FILLING IN ELSEWHERE.
COULD SEE A FEW TENTHS OF AN INCH OF SNOWFALL OUT OF THE MORE
VIGOROUS SNOW SHOWERS. OTHERWISE...LOOK FOR LOWS TOWARD MORNING
FALLING INTO THE SINGLE DIGITS AND TEEN ALONG WITH INCREASING NORTH
WINDS. COLDEST WIND CHILL VALUES TOMORROW MORNING SHOULD RANGE FROM
THE SINGLE DIGITS ACROSS FAR SOUTHWEST WISCONSIN...TO THE SINGLE
DIGITS AND TEENS BELOW ZERO ACROSS THE REST OF THE AREA.
MUCH COLDER CYCLONIC FLOW WILL LINGER ACROSS THE AREA FRIDAY WITH
CONTINUED VERY STEEP LOW LEVEL 0-1KM LAPSE RATES. THIS WILL BE
ENOUGH TO CONTINUE GENERATING FLURRIES. WITH 925MB TEMPERATURES
PLUMMETING INTO THE TEEN BELOW 0C...LOOK FOR HIGHS TO TOP OFF ONLY
IN THE 10-20 DEGREE RANGE. ADDING NORTH WINDS OF 10-25 MPH WILL
YIELD WIND CHILLS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO.
CLEARING SKIES EXPECTED FRIDAY NIGHT AS HIGH PRESSURE BUILDS
SOUTHEAST OUT OF THE CENTRAL CANADIAN PROVINCES INTO THE NORTHERN
PLAINS/UPPER MISSISSIPPI RIVER REGION. TEMPERATURES DROPPING INTO
THE SINGLE DIGITS ABOVE/BELOW ZERO AND NORTH WINDS AROUND 10 MPH ARE
EXPECTED TO PRODUCE SOME FRIGID WIND CHILLS IN THE TEENS/LOWER 20S
BELOW ZERO. MAY HAVE TO KEEP A WATCH FOR POTENTIAL WIND CHILL
HEADLINES LATE FRIDAY NIGHT/EARLY SATURDAY MORNING.
SATURDAY EXPECTED TO BE SUNNY BUT REMAINING VERY CHILLY AS HIGH
PRESSURE SLIDES DOWN THROUGH THE PLAINS. THIS KEEPS A FAIRLY TIGHT
PRESSURE GRADIENT ACROSS OUR AREA WITH FAIRLY BRISK WEST/NORTHWEST
WINDS CONTINUING. HIGHS ARE ONLY EXPECTED TO TOP OFF IN THE TEENS
ONCE AGAIN WITH WIND CHILLS HOVERING IN THE SINGLE DIGITS
ABOVE/BELOW ZERO RANGE.
MOSTLY CLEAR SKIES EXPECTED SATURDAY NIGHT THROUGH SUNDAY AS
THE RIDGE AXIS SLOWLY BUILDS EAST OVER THE AREA. SOME MODERATION IN
TEMPERATURES ALSO EXPECTED WITH LOWS SATURDAY NIGHT IN THE SINGLE
DIGITS ABOVE ZERO AND HIGHS ON SUNDAY IN THE 20S.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
215 PM CST THU FEB 9 2012
09.12Z GFS AND ECMWF IN GENERALLY GOOD AGREEMENT THROUGH
TUESDAY...BUT THEN DIVERGE A BIT AFTER THAT. BOTH MODELS SHOWING
GOOD RUN TO RUN CONTINUITY WITH A WEAK MID-LEVEL TROUGH APPROACHING
THE AREA SUNDAY NIGHT/MONDAY. GFS SHOWS PRETTY DECENT 275-280K LAYER
ISENTROPIC LIFT LATE SUNDAY NIGHT INTO MONDAY AHEAD OF THIS TROUGH.
MAY HAVE TO OVERCOME RESIDUAL FAIRLY DRY LOWER LEVELS AS RIDGE AXIS
DEPARTS EAST OF THE AREA. FOR NOW...WILL CARRY SMALL-END SLIGHT
CHANCE OF -SN ACROSS NORTHEAST IA/SOUTHEAST MN SUNDAY NIGHT AND GO
WITH HIGH-END CHANCE POPS/LIKELY POPS SOUTH OF I-90 ON MONDAY AS THE
TROUGH CONTINUES TO PUSH EAST ACROSS IA/IL/SOUTHERN WI. PRELIMINARY
INDICATIONS ARE THAT THE AREA COULD SEE 1-2 INCHES SOUTH OF
I-90...TAPERING OFF TO PERHAPS A DUSTING NORTHEAST IF I-94.
TUESDAY/TUESDAY NIGHT LOOK DRY FOR NOW AS AS A WEAK RIDGE MOVES
ACROSS THE UPPER MISSISSIPPI RIVER REGION. AS STATED BEFORE...MODELS
GET KIND OF SKETCHY FOR WEDNESDAY/THURSDAY DEALING WITH VARIOUS
ENERGY IN SPLIT FLOW REGIME ACROSS CANADA/CONUS. THE GFS WANTS TO
EJECT A TROUGH NORTHEAST OUT OF THE ROCKIES AND INTO THE REGION
WED/WED N FOR A CHANCE OF LIGHT SNOW WHILE THE ECMWF KEEPS THE AREA
DRY UNDER GENERAL RIDGING. WILL GO WITH A BLEND FOR NOW WITH A VERY
SLIGHT CHANCE OF -SN IN THE GRIDS.
&&
.AVIATION...THROUGH 18Z FRIDAY
1127 AM CST THU FEB 9 2012
A LARGE AREA OF STRATUS WAS LOCATED OVER SOUTHERN IOWA AT
17Z...WITH THE NORTHERN EXTENT EXTENDING INTO NORTHEAST IOWA AND
FAR SOUTHEAST MINNESOTA. MEANWHILE...A COLD FRONT WAS STRETCHED
FROM JUST NORTH OF LAKE SUPERIOR...INTO NORTHERN MINNESOTA. 09.14Z
HRRR ALONG WITH THE 09.15Z RUC DOES SHOW THE STRATUS OVER
NORTHEAST IOWA TO SKIRT ALONG THE TAF SITES THIS AFTERNOON. DID
MENTION A SCATTERED DECK AT BOTH SITES...BUT FEEL CEILINGS WILL BE
SOUTH OF THE AREA. IF CEILINGS DO DEVELOP THEY WILL BE SHORT
LIVED...ESPECIALLY AT KRST. ANY CEILINGS THAT DO DEVELOP WOULD BE IN THE
MVFR CATEGORY. NEXT CONCERN IS ON ARCTIC BOUNDARY THAT WILL PUSH
ACROSS THE TAF SITES LATER TONIGHT. WINDS WILL SWITCH AROUND TO A
WEST THEN NORTHWEST DIRECTION BETWEEN 06Z-09Z WITH SPEEDS
INCREASING AND SOME GUSTS TO 20 TO 23 KNOTS. MVFR STRATUS IS
EXPECTED BEHIND THE FRONT WHICH WILL CONTINUE THROUGH 18Z FRIDAY.
COULD ALSO BE SOME -SHSN...BUT DID NOT BRING ANY RESTRICTIONS TO
VISIBILITY WITHIN THE -SHSN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
215 PM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...RABERDING
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1234 PM CST THU FEB 9 2012
.UPDATE...
TRACKING AREA OF STRATUS CLOUDS THAT MOVED FROM NORTH CENTRAL IOWA
AT 8 AM TO FAR SOUTHWEST WI AROUND NOON TODAY. EXPECTING THE LEADING
EDGE TO SLOW DOWN AND BECOME A LITTLE FUZZY AS IT MOVES EAST DUE TO
MIXING. HOWEVER THE CLOUD TRENDS ARE SHOWING A SOLID LAYER OF
MOISTURE TRAPPED BELOW THE INVERSION OF AROUND 4000 FEET THAT IS
REALLY NOT MIXING OUT DUE TO MIXING ONLY UP TO AROUND 2000 FEET. LOW
CONFIDENCE ON EXACT COVERAGE OF CLOUDS THROUGH THE REST OF THE
AFTERNOON...BUT TIMING OF THE LEADING EDGE BRINGS THEM INTO MADISON
AROUND 2 TO 3 PM. HRRR MARCHES THE STRATUS CLOUDS ACROSS ALL OF
SOUTHERN WI AT A STEADY RATE THIS AFTERNOON...REACHING MILWAUKEE
AROUND 7 PM. IF THE CLOUDS SPREAD ACROSS SOUTHERN WI...THERE SHOULD
BE NO REASON FOR THEM TO LEAVE UNTIL WELL AFTER THE COLD FRONT
PASSES THROUGH.
GIVEN THE LATE ARRIVAL OF THE CLOUDS TODAY...WE SHOULD STILL BE ABLE
TO WARM UP TO THE EXPECTED HIGH TEMPERATURES TODAY...SO WILL NOT BE
MAKING ANY BIG CHANGES. IF CLOUDS STICK AROUND TONIGHT...WE SHOULD
HAVE WARMER THAN EXPECTED LOW TEMPS...SO WILL BE TAKING THIS INTO
CONSIDERATION.
TIGHT PRESSURE GRADIENT ACROSS WISCONSIN DUE TO LOW PRESSURE OVER
SOUTHERN ONTARIO AND HIGH PRESSURE OVER THE KENTUCKY AREA.
WEST-SOUTHWEST WINDS ARE INCREASING THIS AFTERNOON...WITH GUSTS TO
AROUND 20 KNOTS.
&&
.AVIATION/18Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE IS BRINGING AN AREA OF
MVFR STRATUS FROM NORTHEAST IOWA INTO SOUTHERN WI THIS AFTERNOON AND
EARLY EVENING. TIMING OF SATELLITE TRENDS WOULD BRING THE LEADING
EDGE OF THE CLOUD DECK INTO MSN AROUND 3 PM AND HRRR MODEL TIMING
BRINGS IT INTO MKE AROUND 7 PM. IF THIS CLOUD DECK MAKES IT INTO
SOUTHERN WI BY EARLY EVENING...THERE WILL BE NOTHING TO SCOUR IT OUT
DUE TO THE LOW LEVEL INVERSION OVERNIGHT. THE CLOUDS WILL STAY IN
THE REGION UNTIL WELL AFTER THE COLD FRONT CLEARS SOUTHERN
WI...THROUGH AT LEAST FRIDAY AFTERNOON.
THERE IS A GOOD CHANCE FOR SNOW SHOWERS JUST BEHIND THE COLD FRONT
FRIDAY MORNING THROUGH FRIDAY AFTERNOON. NOT EXPECTING HIGH
ACCUMULATIONS...ALTHOUGH LAKE ENHANCED SNOW COULD BRING SLIGHTLY
HIGHER ACCUMS TO THE LAKESHORE AREAS. TOTAL SNOWFALL AMOUNTS SHOULD
BE GENERALLY AROUND A HALF INCH...BUT UP TO 1.5 INCHES AT MKE RAC
ENW. STRONG AND GUSTY NORTH WINDS WILL ACCOMPANY THE SNOW SHOWERS ON
FRIDAY. MVFR VSBY WITH OCCASIONAL IFR VSBYS POSSIBLE.
&&
.MARINE...
INCREASING SOUTHWEST WINDS TODAY AND EARLY TONIGHT WILL APPROACH
SMALL CRAFT ADVISORY CONDITIONS. SMALL CRAFT ADVISORIES ARE IN
EFFECT FOR ALL OF THE SHORE AREAS FRIDAY MORNING INTO FRIDAY NIGHT
BEHIND A STRONG COLD FRONT. THE GUSTY NORTH WINDS WILL CREATE HIGH
WAVES FRIDAY...LASTING INTO SATURDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 9 AM FRIDAY TO 3 PM CST SATURDAY FOR
LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
UPDATE...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1127 AM CST THU FEB 9 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
250 AM CST THU FEB 9 2012
MAIN FORECAST CONCERNS ARE ON LIGHT SNOW/FLURRY CHANCES TONIGHT
THROUGH FRIDAY AND HIGH TEMPERATURES FRIDAY INTO SATURDAY BEHIND
THE ARCTIC COLD FRONT.
CURRENT SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
CENTRAL ONTARIO WEST THROUGH SOUTHERN MANITOBA INTO SOUTHERN
SASKATCHEWAN. THE FRONT WAS MOVING SOUTH EARLY THIS MORNING. AN
AREA OF STRATUS WAS NOTED ACROSS EASTERN NEBRASKA/SOUTHWEST
IOWA...MOVING EAST AND SLIGHTLY NORTHEAST. WILL HAVE TO KEEP A
CLOSE WATCH ON THIS AREA OF STRATUS AS SOUTHWEST WINDS INCREASE
AHEAD OF THE FRONT THIS MORNING INTO THIS AFTERNOON WITH THE
POSSIBILITY OF THE STRATUS ADVECTING INTO THE FORECAST AREA.
HIGH PRESSURE WILL SLIDE SOUTH OF THE REGION TODAY AS THE ARCTIC
COLD FRONT APPROACHES THE REGION. THE HRRR DEVELOPS AN AREA OF
STRATUS ACROSS SOUTHWEST/SOUTH CENTRAL MINNESOTA INTO NORTHEAST IOWA
LATE THIS MORNING...WITH THE STRATUS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS AFTERNOON. FORECAST SOUNDINGS ACROSS
SOUTH CENTRAL MINNESOTA AND NORTHEAST IOWA SHOW VERY DRY AIR IN
THE LOWER LEVELS OF THE ATMOSPHERE LATE THIS MORNING INTO THIS
AFTERNOON. SURFACE DEWPOINTS ACROSS THIS AREA ARE ONLY IN THE
SINGLE DIGITS TO LOWER TEENS WITH THE ONLY APPRECIABLE LOW LEVEL
MOISTURE NOTED IN THE AREA OF STRATUS ACROSS EASTERN NEBRASKA INTO
SOUTHWEST IOWA. PLAN ON MOSTLY SUNNY SKIES THROUGH EARLY AFTERNOON
WITH CLOUDS INCREASING DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS AS THE COLD FRONT MOVES INTO THE FORECAST AREA. THE FRONT IS
EXPECTED TO BE POSITIONED FROM WESTERN LAKE SUPERIOR INTO
SOUTHWEST MINNESOTA BY 6 PM THIS EVENING. LOOK FOR THE FRONT TO
SWEEP ACROSS THE AREA DURING THE EVENING HOURS. THE BEST FORCING
FOR PRECIPITATION APPEARS TO BE RIGHT ALONG AND SLIGHTLY TRAILING
THE COLD FRONT. WOULD EXPECT TO SEE A FEW FLURRIES OR LIGHT SNOW
SHOWERS THIS EVENING INTO THE OVERNIGHT HOURS AS THE FRONT MOVES
THROUGH. NAM FORECAST SOUNDINGS SHOW THE POTENTIAL FOR SNOW
SHOWERS...MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. THE GFS
SHOWS A BRIEF WINDOW OF FLURRIES/LIGHT SNOW SHOWERS THIS EVENING
BEFORE DRY/COLD AIR MOVES IN. A BRIEF SHOT OF ISENTROPIC LIFT
NOTED IN THE LATEST NAM SOLUTION ON THE 270 THROUGH 280 K SURFACES
THIS EVENING WITH CONDENSATION PRESSURE DEFICITS LOWERING TO
AROUND 7 MB WITHIN THIS LAYER. IF LIGHT SNOW DEVELOPS...LITTLE OR
NO ACCUMULATION IS EXPECTED WITH THIS ACTIVITY. WILL INCLUDE A
SLIGHT CHANCE OF VERY LIGHT SNOW ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA INTO SOUTHWEST AND CENTRAL WISCONSIN.
SLIGHTLY HIGHER CHANCES FOR SNOW ACROSS NORTH CENTRAL WISCONSIN.
OTHERWISE...PLAN ON MOSTLY CLOUDY SKIES OVERNIGHT WITH LOW
TEMPERATURES RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE UPPER TEENS ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN.
AN UPPER LEVEL TROUGH IS EXPECTED TO PUSH INTO THE AREA ON
FRIDAY...WITH PV15 SURFACES DIPPING TO 540 MB AS IT MOVES IN. THE
COLDEST AIR ALOFT WILL FILTER IN BEHIND THIS WAVE WITH 900 MB
TEMPERATURES FALLING TO -17C BY FRIDAY AFTERNOON. A RATHER NICE PV
ADVECTION SIGNAL MOVING ACROSS THE FORECAST AREA FRIDAY
MORNING...WITH PV ADVECTION IN THE 500-300 MB LAYER OF AROUND 37
PVU/S. EVEN WITH THIS UPPER LEVEL FORCING...THE LOWER LEVEL ARE
VERY DRY LIMITING OVERALL SNOW CHANCES AS THE WAVE MOVES
THROUGH...WITH LITTLE OR NO CONTRIBUTION FROM FORCING ALOFT.
HOWEVER...GIVEN THE COLD AIR AT 900 MB PRODUCING STEEP LAPSE
RATES...CANNOT RULE OUT A FEW CONVECTIVE SNOW SHOWERS. HAVE
LOWERED PRECIPITATION CHANCES SLIGHTLY. WILL MAINTAIN A SLIGHT
CHANCE OF SNOW SHOWERS THROUGH THE DAY ON FRIDAY EAST OF THE
MISSISSIPPI RIVER. OCCASIONAL FLURRIES CAN BE EXPECTED ACROSS THE
ENTIRE FORECAST AREA. LOOK FOR HIGH TEMPERATURES TO RANGE FROM THE
TEENS ACROSS NORTHERN WISCONSIN TO AROUND 20 ACROSS FAR SOUTHWEST
WISCONSIN. COLD SURFACE HIGH PRESSURE IS EXPECTED TO BUILD INTO
THE FORECAST AREA FRIDAY NIGHT...WITH THE CENTER OF THE HIGH
POSITIONED OVER THE DAKOTAS. LOOK FOR CLOUDS TO GRADUALLY DECREASE
FROM NORTH TO SOUTH LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING
AS DRIER LOW LEVEL AIR ADVECTS IN AND ERODES ANY LINGERING
STRATUS. LOW TEMPERATURES FRIDAY NIGHT WILL BE ON THE CHILLY
SIDE...WITH LOWS RANGING FROM THE SINGLE DIGITS BELOW ZERO ACROSS
NORTH CENTRAL WISCONSIN TO THE SINGLE DIGITS ABOVE ZERO ACROSS
NORTHEAST IOWA.
LOW PRESSURE WILL DROP SOUTH ACROSS JAMES BAY INTO CENTRAL QUEBEC ON
SATURDAY. MEANWHILE...COLD HIGH PRESSURE IS EXPECTED TO BE CENTERED
OVER THE DAKOTAS. THIS WILL PRODUCE A TIGHT PRESSURE GRADIENT ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY WITH WEST WINDS INCREASING INTO
THE 10 TO 18 MPH RANGE. HIGHS ON SATURDAY WILL BE MAINLY IN THE
TEENS TO AROUND 20 ACROSS NORTHEAST IOWA INTO FAR SOUTHERN
WISCONSIN. PLAN ON WIND CHILLS IN THE SINGLE DIGITS ABOVE TO
SINGLE DIGITS BELOW ZERO ON SATURDAY. LOOK FOR ONE MORE CHILLY
NIGHT SATURDAY NIGHT WITH LOWS DROPPING INTO SINGLE DIGITS. WEST
WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT AS THE RIDGE AXIS
MOVES INTO THE UPPER MISSISSIPPI RIVER VALLEY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
250 AM CST THU FEB 9 2012
09.00 MEDIUM RANGE MODELS IN AGREEMENT ON SUNDAY SHOWING AN UPPER
RIDGE ACROSS THE FORECAST AREA WITH A TROUGH DIVING INTO THE
SOUTHWEST CONUS. WARMER TEMPERATURES ARE ON TAP FOR SUNDAY AS 850
MB TEMPS WARM TO AROUND -4 C BY SUNDAY AFTERNOON. PLAN ON MOSTLY
SUNNY SKIES ON SUNDAY WITH HIGH TEMPERATURES IN THE 20S. THE TROUGH
WILL EJECT INTO THE CENTRAL/NORTHERN PLAINS LATE SUNDAY NIGHT AND
MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY ON MONDAY. THIS SYSTEM
IS EXPECTED TO BRING LIGHT SNOW TO THE FORECAST AREA...WITH LIGHT
ACCUMULATIONS POSSIBLE. LATEST GUIDANCE SUGGEST 1 TO 3 INCHES OF
ACCUMULATION. WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT FEW MODEL
RUNS. IF TRENDS CONTINUE...SNOW CHANCES WILL LIKELY BE INCREASED
SIGNIFICANTLY. GOOD MODEL AGREEMENT TUESDAY INTO WEDNESDAY SHOWING
ZONAL FLOW ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MODELS MUCH
DRIER THIS RUN ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WITH QUIET ZONAL FLOW ACROSS THE REGION. HAVE DECIDED
TO REMOVE PRECIPITATION CHANCES THROUGH THIS PERIOD. LOOK FOR HIGH
TEMPERATURES IN THE LOW TO MID 30S TUESDAY INTO WEDNESDAY...WITH
OVERNIGHT LOWS IN THE 20S.
&&
.AVIATION...THROUGH 18Z FRIDAY
1127 AM CST THU FEB 9 2012
A LARGE AREA OF STRATUS WAS LOCATED OVER SOUTHERN IOWA AT
17Z...WITH THE NORTHERN EXTENT EXTENDING INTO NORTHEAST IOWA AND
FAR SOUTHEAST MINNESOTA. MEANWHILE...A COLD FRONT WAS STRETCHED
FROM JUST NORTH OF LAKE SUPERIOR...INTO NORTHERN MINNESOTA. 09.14Z
HRRR ALONG WITH THE 09.15Z RUC DOES SHOW THE STRATUS OVER
NORTHEAST IOWA TO SKIRT ALONG THE TAF SITES THIS AFTERNOON. DID
MENTION A SCATTERED DECK AT BOTH SITES...BUT FEEL CEILINGS WILL BE
SOUTH OF THE AREA. IF CEILINGS DO DEVELOP THEY WILL BE SHORT
LIVED...ESPECIALLY AT KRST. ANY CEILINGS THAT DO DEVELOP WOULD BE IN THE
MVFR CATEGORY. NEXT CONCERN IS ON ARCTIC BOUNDARY THAT WILL PUSH
ACROSS THE TAF SITES LATER TONIGHT. WINDS WILL SWITCH AROUND TO A
WEST THEN NORTHWEST DIRECTION BETWEEN 06Z-09Z WITH SPEEDS
INCREASING AND SOME GUSTS TO 20 TO 23 KNOTS. MVFR STRATUS IS
EXPECTED BEHIND THE FRONT WHICH WILL CONTINUE THROUGH 18Z FRIDAY.
COULD ALSO BE SOME -SHSN...BUT DID NOT BRING ANY RESTRICTIONS TO
VISIBILITY WITHIN THE -SHSN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 AM CST THU FEB 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...RABERDING