Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/12/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
821 PM MST SAT FEB 11 2012
.UPDATE...
&&
.AVIATION...MAIN QUESTION LATER TONIGHT THROUGH SUNDAY MORNING
WILL BE IF FOG DEVELOPS OVER SRN WELD COUNTY AND THEN MIGRATES
INTO DIA BY 12Z AS A WEAK DENVER CYCLONE REMAINS OVER THE AREA.
RUC AND WRF ONLY SHOW PATCHY FOG WHILE THE LATEST HRRR SHOWS MUCH
MORE FOG COVERAGE WITH POSSIBLE DENSE FOG MOVING INTO DIA BY 12Z
AS IT SPREADS SE BEHIND WEAK DENVER CYCLONE. AT THIS TIME MAY
INTRODUCE A TEMPO GROUP BETWEEN 11Z AND 15Z FOR SOME IFR/LIFR
CONDITIONS IN 06Z TAF.
&&
.PREV DISCUSSION... /ISSUED 251 PM MST SAT FEB 11 2012/
SHORT TERM...SOME CLEARING THIS AFTERNOON OVER THE FRONT RANGE
HAS ALLOWED SOME LOW LEVEL INSTABLITY TO DEVELOP AND HENCE A FEW
FLURRIES REMAIN ONGOING IN AND NEAR THE FOOTHILLS. ALSO SOME
LIGHT SNOW STILL OVER THE FAR NORTHEAST PLAINS MORE IN CONJUNCTION
WITH THE EXITING JET STREAK NEBRASKA AND KANSAS. WITH THE NEXT
PACIFIC TROF DEVELOPING ACROSS THE WESTERN GREAT BASIN...THERE IS
A BATCH OF MAINLY MIDDLE AND HIGH LEVEL CLOUDS MOVING INTO WESTERN
COLORADO. DESPITE THE LACK OF LOW LEVEL MOISTURE THERE IS SOME
WEAK ASCENT WITH THIS FEATURE AND MAY ALSO BE AIDING IN THE VERY
LIGHT SNOWFALL IN SPOTS. AS WE LOOSE THE BRIEF SURFACE HEATING
THIS EVENING MOST OF THE LINGERING SNOW SHOULD DISSIPATE. CROSS
SECTIONS SHOW MOISTURE LEVELS BECOMING EVEN MORE SHALLOW AFTER
THIS EVENING AND WILL REMOVE MOST OF THE POPS OVERNIGHT. FORECAST
SOUNDINGS LOOK MORE LIKE FOG FOR LATER TNT SO HAVE REMOVED THE
FREEZING DRIZZLE AS MOISTURE WILL EVEN BE TOO SHALLOW.
ON SUNDAY...PATCHY FOG WILL DISSIPATE OVER THE NORTHEAST PLAINS
WHILE DEEPER MOISTURE BEGINS TO MOVE BACK INTO THE MOUNTAINS AND
FRONT RANGE DURING THE DAY. WILL UNDERCUT MOS TEMPS FOR SUNDAY AS
CURRENT SNOW COVER AND LOW LEVEL INVERSIONS SHOULD KEEP TEMPS IN
THE UPPER 20S AND LOWER 30S.
LONG TERM...UPPER TROUGH WILL PASS OVER THE STATE SUNDAY EVENING
AND SEND A COLD FRONT SOUTH ACROSS THE AREA. SNOW WILL CONTINUE
THROUGH THE EVENING HOURS OVER THE HIGH COUNTRY AND SPREAD EAST
ACROSS THE PLAINS. THIS SYSTEM IS A FAST MOVER...SO NOT EXPECTING
A LOT IN THE WAY OF ACCUMULATION. SHOULD SEE ABOUT 2 TO 4 INCHES
OVER THE MOUNTAINS SUNDAY NIGHT AND WITH AN INCH OR LESS OVER THE
PLAINS. THE EXCEPTION WOULD BE THE FAR NORTHEASTERN PLAINS WHERE
BETTER DYNAMICS MAY ALLOW UP TO A COUPLE INCHES. EVEN THOUGH A
COLD FRONT WILL MOVE THROUGH...NORTHEASTERN COLORADO WILL ACTUALLY
SEE TEMPERATURES RISING AS THE DISTURBANCE WILL BRING IN WESTERLY
LOW LEVEL WINDS TO HELP BREAK THE INVERSION THAT HAS BEEN KEEPING
IN THE COLDER TEMPERATURES. EXPECT CLOSER TO NORMAL TEMPERATURES
SUNDAY NIGHT THROUGH MONDAY NIGHT. A FEW AREAS OF LIGHT SNOW WILL
CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS MONDAY AS AN
UPPER RIDGE MOVES OVERHEAD.
THE NEXT SYSTEM WILL DIG DOWN FROM THE PACIFIC NORTHWEST INTO
CALIFORNIA AND SOUTHERN NEVADA BY TUESDAY MORNING. SOUTHWEST FLOW
ALOFT AHEAD OF THIS SYSTEM WILL INCREASE MOISTURE OVER THE STATE
WITH HIGH AND MID LEVEL CLOUDS. SNOW WILL BE INCREASING OVER THE
MOUNTAINS IN THE MORNING THEN BRING A CHANCE OF SNOW TO THE PLAINS
FOR THE EVENING INTO WEDNESDAY AFTERNOON. THE DISTURBANCE WILL
DEEPEN A SURFACE LOW OVER THE SOUTHEASTERN CORNER OF THE STATE TO
CREATE UPSLOPE FLOW DURING THE AFTERNOON AND INTO THE EVENING. THE
SYSTEM IS A BIT FURTHER SOUTH WHICH WILL KEEP MOST OF THE
PRECIPITATION IN THE SOUTHERN PART OF THE STATE. WILL KEEP THE
CHANCE POPS FOR NOW. SLIGHTLY COLDER TEMPERATURES WILL BE PULLED
SOUTH WITH THIS SYSTEM...BUT SHOULD STILL HAVE HIGH TEMPERATURES
IN THE 30S FOR THE PLAINS AND 20S TO 30S FOR THE MOUNTAINS TUESDAY
AND WEDNESDAY.
THOUGH MODELS ARE DISAGREEING ON THE DEPTH AND STRENGTH OF THE
TUESDAY/WEDNESDAY SYSTEM...THEY COME TOGETHER ON YET ANOTHER
TROUGH DIGGING DOWN THE WEST COAST FURTHER INTO ALMOST A CUTOFF
LOW INTO NORTHERN MEXICO. THIS WILL BRING WARMER AND DRIER
CONDITIONS TO ALL OF NORTHEASTERN COLORADO FOR THURSDAY AND
FRIDAY AND POTENTIALLY SATURDAY.
AVIATION...CEILINGS HAVE SCATTERED OUT THIS AFTN BUT WITH THE
HEATING AND LIGHT SNOW REDEVELOPING...FEEL WILL SEE SOME SCT-BKN
STRAUS REDEVELOPING THRU EARLY THIS EVENING ESP AT BJC. MAIN
QUESTION WILL BE IF FOG DEVELOPS TONIGHT? WITH DENVER CYCLONE IN
PLACE SHOULD BE ABLE TO WRAP LOW LEVEL MOISTURE BACK AROUND FROM
THE NORTH OVERNIGHT. MOS GUIDANCE IS NOT VERY BULLISH ON FOG TNT
BUT FORECAST SOUNDINGS SURE LOOK GOOD FOR FOG. AS FOR THE
WINDS...TERMINALS SHOULD REMAIN OUT OF THE NORTH TO
NORTHEAST...THEN BJC AND APA SHOULD BECOME MORE NORTHWEST
OVERNIGHT ON BACKSIDE OF CYCLONE. WILL PLAY FOR MORE WIDESPREAD
FOG AT THE TERMINALS AFTER MIDNIGHT TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....KRIEDERMAN
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS ALBANY NY
957 PM EST SAT FEB 11 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION THIS EVENING...AND
USHER ARCTIC AIR IN. A SECONDARY COLD FRONT WILL DROP SOUTH THE
THE REGION SUNDAY. AS IT MOVES ACROSS LAKE ONTARIO IT WILL TRIGGER
LAKE EFFECT SNOW IN PARTS OF THE REGION. HIGH PRESSURE WILL BUILD
OVER THE EASTERN HALF OF THE NATION MONDAY INTO TUESDAY. TEMPERATURES
WILL MODERATE AS THIS HIGH SLIDES OFFSHORE MIDWEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 945 PM...TEMPERATURES CONTINUE TO DROP AND WINDS REMAIN
ELEVATED. PER THE LATEST LAMP/LAV GUIDANCE AND MESONET OBS...SEEMS
WE WILL HAVE WIND CHILL ISSUES FOR PORTIONS OF THE DACKS AND
SOUTHERN GREENS. WE WILL HOIST WIND CHILL ADVISORIES AT THIS TIME.
OTHERWISE...A COMBINATION OF SOME LOW STRATUS ACROSS THE HUDSON
RIVER VALLEY AND DEPARTING MID AND HIGH LEVEL MOISTURE ARE MAKING
FOR A CHALLENGING SKY FORECAST. STILL EXPECT SUBSIDENCE AND MIXING
TO REDUCE CLOUD COVER FURTHER BEFORE RETURNING LATE TONIGHT
DOWNWIND OF LAKE ONTARIO. HAVE LOWERED TEMPERATURES A COUPLE OF
DEGREES AND INCREASED WINDS SLIGHTLY.
AS OF 645 PM...A MESOSCALE FEATURE WAS ROTATING ACROSS THE SCHOHARIE
VALLEY AND TRACKING ACROSS THE EASTERN CATSKILLS THIS EARLY
EVENING. HRRR SEEMS TO HAVE A HINT OF THIS FEATURE AS IT SHOULD
CONTINUE TO TRACK SOUTHWARD AND WEAKEN TOWARD 03Z. EXPECTATIONS ARE
FOR A LULL IN THE PRECIP COVERAGE BETWEEN 03Z-09Z OVERNIGHT AS THE
COMBINATION OF THE DRIER AIR ADVECTING INTO THE REGION AND A BRIEF
WINDOW OF SUBSIDENCE. SO FOR THIS UPDATE...WE WILL CARRY POPS FOR
THE SOUTHERN 1/3RD OF NY COUNTIES THEN GO DRY FOR THAT PERIOD OF
03-09Z. PER THE LATEST NAM12/HRRR/RUC13...SEEMS THE BEST TRAJECTORY
FOR LAKE EFFECT SETS UP A LITTLE MORE NORTHWEST THAN PREVIOUS RUNS.
THIS WOULD LIMIT THE SNOW MIGRATING THROUGH THE MOHAWK VALLEY. WE
WILL AWAIT FOR THE 00Z GUIDANCE BEFORE MAKING ADDITIONAL
ENHANCEMENTS TO THE GRIDS/FORECAST.
PREV DISC...
SFC LOW PRESSURE WILL ORGANIZE WELL OFFSHORE THIS AFTERNOON. -SN
ASSOCIATED WITH THIS SYSTEM HAS ALREADY EXITED MOST OF RGN. MORE
SIGNIFICANT WEATHER STORY TODAY WILL BE A VERY SHARP 500HPA TROF
MOVING ACROSS THE RGN THIS AFTN AND EVNG. IT WILL DRIVE THE ARCTIC
FRONT THROUGH THE RGN WHICH WILL BE ABSORBED INTO THE DEEPENING
COASTAL SYSTEM WELL OFFSHORE. FOR A FEW HOURS AHEAD OF CDFNT FCA
WILL SEE SUNNY INTERVALS THIS AFTN.
MOST OF THE DYNAMICS WITH THIS SYSTEM WILL PASS SOUTH OF FCA...BUT
STRONG SHORT WV WILL RESULT IN SCT -SNSH INTO THE EVNG. LATE TNGT
AND SUN A NW-SE ORIENTED 2SECONDARY CDFNT WILL DROP SOUTH THROUGH NY.
WITH A PARADE OF SHORT WVS SLIDING SE IN 500HPA TROF OVER
RGN...AND THIS BOUNDARY ALIGNING ACROSS MULTIPLE GRTLKS FOR A TIME
IT IS LIKELY TO FOCUS A SHARP LAKE EFFECT RESPONSE LATE TONIGHT
INTO SUN MORNING AS INSTAB REACHES MODERATE...850HPA FLOW FLUCTUATES
290-300 WHICH COULD SEND -SHSN AND MAYBE SQUALLS DOWN THE MHWK VLY
FOR A TIME. IT WILL DIMINISH TWRD EVNG AS INVERSION HT PUSHES FM
10KFT TO 5KFT. TEMPS THE REST OF THE WEEKEND WILL BE BLO NORMALS.
WINDS WILL BCM BRISK TONG HT 10-20KTS...BUT WILL LESSEN AS THE
2NDARY CDFNT INTERACTS WITH THE PREVAILING N-NNW FLOW.
&&
.SHORT TERM /SUNDAY NIGHT/...
A FAIR AMOUNT OF AGREEMENT AMONG GFS/NAM/CMC DURING THIS PERIOD.
AT 500HPA CUT OFF TROF IS LIFTING INTO N ATLC. RIDGE AXIS IS
BUILDING FM SE USA TO N GRT PLAINS. MODELS ALL SHOW A WK LK
RESPONSE SIGNAL AS WHAT WAS A CDFNT LIFTS BACK NE THROUGH RGN INTO
QB MON. IT MAY FOCUS SOME -SHSN INTO W FCA OR IS BEING ENHANCED BY
WK WAA. BUT WITH INVERSION HGT AT 5KFT NOT EXPECTING MUCH SUN NT
IN WAY OF -SHSN.
MONDAY WITH 500HPA RIDGE AXIS TO OUR W...SFC HIGH SHIFTING TO EAST
COAST SHOULD BE A FAIR DAY WITH MODERATING TEMPS AFTER A COLD START.
MONDAY NT SFC HIGH SLIDES OFFSHORE AND 500HPA FLOW RETURNS TO A
ZONAL PATTERN WITH A FEW EMBEDDED WEAK SHORT WAVES.
A SERIES OF WEAK 500HPA SHORT WVS APPROACH LATE MON AND TUES WITH
INCRG CLOUDS TUES MORNING. MIDWEEK FINDS FCA IN ANOTHER MODIFIED
MARITIME POLAR AIR MASS THAT HAS TRAVELED ZONALLY ACROSS MUCH OF
THE USA. SFC HIGH OFFSHORE SETS UP SW FLOW W/FAIR AMOUNT OF
CLOUDINESS...AND MAYBE SOME LT PCPN OF VARIOUS FORMS MAINLY DZ OR
FZDZ IN THE EARLY MORNING HRS. NOT MUCH DYNAMICALLY GOING ON...JUST
CLOUDS STUCK UNDER INVERSIONS. TEMPS WELL ABV NORMALS AFTER A
CHILLY START MONDAY MORNING.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
STILL A CHALLENGING LONG TERM PORTION OF THE FORECAST AS SEVERAL KEY
SHORT WAVES WERE SITUATED OVER THE NORTH PACIFIC THAT WILL HAVE
IMPLICATIONS FOR THE END OF NEXT WEEK.
WE BEGIN THIS LONG TERM FORECAST WITH A DEPARTING WAVE. MAINLY
CLOUDS ARE EXPECTED WITH THIS SYSTEM WITH GRADUAL IMPROVEMENTS
EXPECTED THROUGH THE DAY. EXCEPTION WOULD BE ACROSS THE HIGHER
TERRAIN AS MOIST LOW-MID LEVELS AND UPSLOPING CONDITIONS SHOULD
RESULT IN ENHANCED CLOUD COVER A BIT LONGER. BOUNDARY LAYER
TEMPERATURES ARE EXPECTED TO MODERATE SO ANY SNOW IN THE VALLEYS
SHOULD REDUCE.
THEN A RIDGE OF HIGH PRESSURE IS EXPECTED FROM LATE WEDNESDAY INTO
THURSDAY. THIS WILL KEEP OUR WEATHER TRANQUIL FOR THE MAJORITY OF
THE REGION. THE MINOR EXCEPTION TO THIS WOULD BE DOWNWIND OF LAKE
ONTARIO WHERE A WEAK THERMAL TROUGH MAY BE ENOUGH TO PRODUCE A MINOR
LAKE RESPONSE AND WILL KEEP POPS LOW AT THIS TIME. TEMPERATURES
DURING THIS TIME FRAME WILL AVERAGE A BIT ABOVE NORMAL FOR THIS TIME
OF THE YEAR.
THEN THE RATHER COMPLEX FORECAST FOR THURSDAY-FRIDAY TIME FRAME.
OUR POTENTIAL WAVE...PER THE 1.5PVU TRACE AND H2O VAPOR LOOP
ANALYSIS...WAS CURRENTLY TRACKING ALONG 45N AND JUST EAST OF 160W.
SATELLITE REPRESENTATION DOES SUGGEST THIS WAVE IS STRONG AS IT
RACES EAST TOWARD THE PACIFIC COASTLINE OF NOAM. NCEP MODEL SUITE
AN INTERNATIONAL GUIDANCE ALL OFFER A UNIQUE APPROACH THAT WILL HAVE
LARGE IMPLICATIONS ON OUR WEATHER. THE ECMWF WHICH HAS WAVERED A
BIT THE PAST SEVERAL RUNS...RETURNS WITH A RATHER STRONG SYSTEM
IMPACTING THE NORTHEAST. THE GFS REMAINS QUITE PROGRESSIVE AND
FAVORS A STRONGER HUDSON BAY LOW /AND A MORE POSITIVE NAO/. THE
CANADIAN TAKES THE STRONG BALANCE OF THESE AFOREMENTIONED FEATURES
WHICH SLOWS DOWN THE FORWARD PROGRESS OF THE PENDING EVENT BY ABOUT
1 DAY /ALSO A WARMER SOLUTION/. PLUMES/ENSEMBLES FROM THE GFS
REVEAL A CLUSTERING OF SOLUTIONS OF FURTHER SOUTHWARD TRACK AND MORE
PROGRESSIVE. ALTHOUGH WE CAN NOT RULE OUT THE ECMWF WHICH A COUPLE
OF THE GFS PERTURBATIONS DO AGREE WITH ITS OPERATIONAL SOLUTION. SO
A LOW CONFIDENCE FORECAST AT THIS TIME AND WILL KEEP POPS AROUND THE
30% THRESHOLDS WHICH IS IN AGREEMENT WITH HPC AND NEIGHBORING
FORECAST OFFICES. BOUNDARY LAYER TEMPS WILL ALSO BE TRICKY AS THE
RAIN/SNOW ISSUE IS EXPECTED TO BECOME A FACTOR AS WELL.
A CYCLONIC FLOW REGIME IS EXPECTED FOR THE START OF NEXT WEEKEND
WITH SOME SHOWER ACTIVITY AND PERHAPS SOME LAKE ONTARIO CONTRIBUTION
WHICH WILL BE HIGHLY DEPENDENT ON HOW MUCH COLD ADVECTION TAKES
PLACES IN THE WAKE OF THE THURSDAY-FRIDAY EVENT.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
AN ARCTIC FRONT HAD SLIPPED SOUTH THROUGH KALB AS OFF 2330Z...
HEADED TOWARD KPOU. KPOU ASOS HAD RECORDED CLR SKIES...BUT BASED ON
SATELLITE IMAGERY...WHATEVER CLEARING WAS OVERHEAD WILL FILL IN TO
AT LEAST BKN RATHER QUICKLY. NORTHWARD AT THE OTHER TWO AIRPORTS...
ENOUGH DRY AIR HAD INFILTRATED TO RESULT IN A SCT CLOUD NIGHT AS
CIGS ERODE. EASILY LOOKING AT VFR THROUGHOUT THE TAF PERIOD.
SFC WINDS ARE THE FOCUS...WITH DAYTIME NORTHWEST WINDS SUNDAY AROUND
15 KTS...AND GUSTS FREQUENTING THE 20 TO 30 KT RANGE. WITH PRETTY
UNIFORM WINDS THROUGH THE VERTICAL COLUMN...SHEAR IS OF NO CONCERN.
A WEAK REINFORCING COLD FRONT WILL HAVE PRACTICALLY NO MOISTURE
ASSOCIATED WITH IT...SO THIS WILL HAVE NO NOTICEABLE IMPACT AT THE
AIRPORTS ON SUNDAY OTHER THAN TO KEEP THE STRONG NORTHWEST FLOW
GOING.
OUTLOOK...
SUN NGT-MON NGT...VFR...NO SIG WX. BRISK DAYTIME.
TUE-WED NGT...VFR...NO SIG WX.
THU...VFR...CHC PM -RA.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT SEVERAL DAYS. SOME
GAGES WILL CONTINUE TO BE IMPACTED BY ICE ACROSS NORTHERN PORTIONS
OF THE HYDROLOGIC SERVICE AREA.
COLDER AIR WILL BE USHERED IN THE REGION TONIGHT AND SHOULD LEAD
TO SOME ADDITIONAL ICE FORMATION ESPECIALLY ACROSS THE SOUTHERN
ADIRONDACKS...AND AREAS NORTH OF THE MOHAWK RIVER VALLEY.
HOWEVER...TEMPERATURES WILL MODERATE TO ABOVE NORMAL NEXT WEEK.
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...WIND CHILL ADVISORY UNTIL 9 AM EST SUNDAY FOR NYZ032-033.
MA...NONE.
VT...WIND CHILL ADVISORY UNTIL 9 AM EST SUNDAY FOR VTZ013-014.
&&
$$
NEAR TERM...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
655 PM EST SAT FEB 11 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH THROUGH THE REGION THIS EVENING...AND
USHER ARCTIC AIR IN. A SECONDARY COLD FRONT WILL DROP SOUTH THE
THE REGION SUNDAY. AS IT MOVES ACROSS LAKE ONTARIO IT WILL TRIGGER
LAKE EFFECT SNOW IN PARTS OF THE REGION. HIGH PRESSURE WILL BUILD
OVER THE EASTERN HALF OF THE NATION MONDAY INTO TUESDAY. TEMPERATURES
WILL MODERATE AS THIS HIGH SLIDES OFFSHORE MIDWEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 645 PM...A MESOSCALE FEATURE WAS ROTATING ACROSS THE SCHOHARIE
VALLEY AND TRACKING ACROSS THE EASTERN CATSKILLS THIS EARLY
EVENING. HRRR SEEMS TO HAVE A HINT OF THIS FEATURE AS IT SHOULD
CONTINUE TO TRACK SOUTHWARD AND WEAKEN TOWARD 03Z. EXPECTATIONS ARE
FOR A LULL IN THE PRECIP COVERAGE BETWEEN 03Z-09Z OVERNIGHT AS THE
COMBINATION OF THE DRIER AIR ADVECTING INTO THE REGION AND A BRIEF
WINDOW OF SUBSIDENCE. SO FOR THIS UPDATE...WE WILL CARRY POPS FOR
THE SOUTHERN 1/3RD OF NY COUNTIES THEN GO DRY FOR THAT PERIOD OF
03-09Z. PER THE LATEST NAM12/HRRR/RUC13...SEEMS THE BEST TRAJECTORY
FOR LAKE EFFECT SETS UP A LITTLE MORE NORTHWEST THAN PREVIOUS RUNS.
THIS WOULD LIMIT THE SNOW MIGRATING THROUGH THE MOHAWK VALLEY. WE
WILL AWAIT FOR THE 00Z GUIDANCE BEFORE MAKING ADDITIONAL
ENHANCEMENTS TO THE GRIDS/FORECAST.
PREV DISC...
SFC LOW PRESSURE WILL ORGANIZE WELL OFFSHORE THIS AFTERNOON. -SN
ASSOCIATED WITH THIS SYSTEM HAS ALREADY EXITED MOST OF RGN. MORE
SIGNIFICANT WEATHER STORY TODAY WILL BE A VERY SHARP 500HPA TROF
MOVING ACROSS THE RGN THIS AFTN AND EVNG. IT WILL DRIVE THE ARCTIC
FRONT THROUGH THE RGN WHICH WILL BE ABSORBED INTO THE DEEPENING
COASTAL SYSTEM WELL OFFSHORE. FOR A FEW HOURS AHEAD OF CDFNT FCA
WILL SEE SUNNY INTERVALS THIS AFTN.
MOST OF THE DYNAMICS WITH THIS SYSTEM WILL PASS SOUTH OF FCA...BUT
STRONG SHORT WV WILL RESULT IN SCT -SNSH INTO THE EVNG. LATE TNGT
AND SUN A NW-SE ORIENTED 2SECONDARY CDFNT WILL DROP SOUTH THROUGH NY.
WITH A PARADE OF SHORT WVS SLIDING SE IN 500HPA TROF OVER
RGN...AND THIS BOUNDARY ALIGNING ACROSS MULTIPLE GRTLKS FOR A TIME
IT IS LIKELY TO FOCUS A SHARP LAKE EFFECT RESPONSE LATE TONIGHT
INTO SUN MORNING AS INSTAB REACHES MODERATE...850HPA FLOW FLUCTUATES
290-300 WHICH COULD SEND -SHSN AND MAYBE SQUALLS DOWN THE MHWK VLY
FOR A TIME. IT WILL DIMINISH TWRD EVNG AS INVERSION HT PUSHES FM
10KFT TO 5KFT. TEMPS THE REST OF THE WEEKEND WILL BE BLO NORMALS.
WINDS WILL BCM BRISK TONG HT 10-20KTS...BUT WILL LESSEN AS THE
2NDARY CDFNT INTERACTS WITH THE PREVAILING N-NNW FLOW.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A FAIR AMOUNT OF AGREEMENT AMONG GFS/NAM/CMC DURING THIS PERIOD.
AT 500HPA CUT OFF TROF IS LIFTING INTO N ATLC. RIDGE AXIS IS
BUILDING FM SE USA TO N GRT PLAINS. MODELS ALL SHOW A WK LK
RESPONSE SIGNAL AS WHAT WAS A CDFNT LIFTS BACK NE THROUGH RGN INTO
QB MON. IT MAY FOCUS SOME -SHSN INTO W FCA OR IS BEING ENHANCED BY
WK WAA. BUT WITH INVERSION HGT AT 5KFT NOT EXPECTING MUCH SUN NT
IN WAY OF -SHSN.
MONDAY WITH 500HPA RIDGE AXIS TO OUR W...SFC HIGH SHIFTING TO EAST
COAST SHOULD BE A FAIR DAY WITH MODERATING TEMPS AFTER A COLD START.
MONDAY NT SFC HIGH SLIDES OFFSHORE AND 500HPA FLOW RETURNS TO A
ZONAL PATTERN WITH A FEW EMBEDDED WEAK SHORT WAVES.
A SERIES OF WEAK 500HPA SHORT WVS APPROACH LATE MON AND TUES WITH
INCRG CLOUDS TUES MORNING. MIDWEEK FINDS FCA IN ANOTHER MODIFIED
MARITIME POLAR AIR MASS THAT HAS TRAVELED ZONALLY ACROSS MUCH OF
THE USA. SFC HIGH OFFSHORE SETS UP SW FLOW W/FAIR AMOUNT OF
CLOUDINESS...AND MAYBE SOME LT PCPN OF VARIOUS FORMS MAINLY DZ OR
FZDZ IN THE EARLY MORNING HRS. NOT MUCH DYNAMICALLY GOING ON...JUST
CLOUDS STUCK UNDER INVERSIONS. TEMPS WELL ABV NORMALS AFTER A
CHILLY START MONDAY MORNING.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
STILL A CHALLENGING LONG TERM PORTION OF THE FORECAST AS SEVERAL KEY
SHORT WAVES WERE SITUATED OVER THE NORTH PACIFIC THAT WILL HAVE
IMPLICATIONS FOR THE END OF NEXT WEEK.
WE BEGIN THIS LONG TERM FORECAST WITH A DEPARTING WAVE. MAINLY
CLOUDS ARE EXPECTED WITH THIS SYSTEM WITH GRADUAL IMPROVEMENTS
EXPECTED THROUGH THE DAY. EXCEPTION WOULD BE ACROSS THE HIGHER
TERRAIN AS MOIST LOW-MID LEVELS AND UPSLOPING CONDITIONS SHOULD
RESULT IN ENHANCED CLOUD COVER A BIT LONGER. BOUNDARY LAYER
TEMPERATURES ARE EXPECTED TO MODERATE SO ANY SNOW IN THE VALLEYS
SHOULD REDUCE.
THEN A RIDGE OF HIGH PRESSURE IS EXPECTED FROM LATE WEDNESDAY INTO
THURSDAY. THIS WILL KEEP OUR WEATHER TRANQUIL FOR THE MAJORITY OF
THE REGION. THE MINOR EXCEPTION TO THIS WOULD BE DOWNWIND OF LAKE
ONTARIO WHERE A WEAK THERMAL TROUGH MAY BE ENOUGH TO PRODUCE A MINOR
LAKE RESPONSE AND WILL KEEP POPS LOW AT THIS TIME. TEMPERATURES
DURING THIS TIME FRAME WILL AVERAGE A BIT ABOVE NORMAL FOR THIS TIME
OF THE YEAR.
THEN THE RATHER COMPLEX FORECAST FOR THURSDAY-FRIDAY TIME FRAME.
OUR POTENTIAL WAVE...PER THE 1.5PVU TRACE AND H2O VAPOR LOOP
ANALYSIS...WAS CURRENTLY TRACKING ALONG 45N AND JUST EAST OF 160W.
SATELLITE REPRESENTATION DOES SUGGEST THIS WAVE IS STRONG AS IT
RACES EAST TOWARD THE PACIFIC COASTLINE OF NOAM. NCEP MODEL SUITE
AN INTERNATIONAL GUIDANCE ALL OFFER A UNIQUE APPROACH THAT WILL HAVE
LARGE IMPLICATIONS ON OUR WEATHER. THE ECMWF WHICH HAS WAVERED A
BIT THE PAST SEVERAL RUNS...RETURNS WITH A RATHER STRONG SYSTEM
IMPACTING THE NORTHEAST. THE GFS REMAINS QUITE PROGRESSIVE AND
FAVORS A STRONGER HUDSON BAY LOW /AND A MORE POSITIVE NAO/. THE
CANADIAN TAKES THE STRONG BALANCE OF THESE AFOREMENTIONED FEATURES
WHICH SLOWS DOWN THE FORWARD PROGRESS OF THE PENDING EVENT BY ABOUT
1 DAY /ALSO A WARMER SOLUTION/. PLUMES/ENSEMBLES FROM THE GFS
REVEAL A CLUSTERING OF SOLUTIONS OF FURTHER SOUTHWARD TRACK AND MORE
PROGRESSIVE. ALTHOUGH WE CAN NOT RULE OUT THE ECMWF WHICH A COUPLE
OF THE GFS PERTURBATIONS DO AGREE WITH ITS OPERATIONAL SOLUTION. SO
A LOW CONFIDENCE FORECAST AT THIS TIME AND WILL KEEP POPS AROUND THE
30% THRESHOLDS WHICH IS IN AGREEMENT WITH HPC AND NEIGHBORING
FORECAST OFFICES. BOUNDARY LAYER TEMPS WILL ALSO BE TRICKY AS THE
RAIN/SNOW ISSUE IS EXPECTED TO BECOME A FACTOR AS WELL.
A CYCLONIC FLOW REGIME IS EXPECTED FOR THE START OF NEXT WEEKEND
WITH SOME SHOWER ACTIVITY AND PERHAPS SOME LAKE ONTARIO CONTRIBUTION
WHICH WILL BE HIGHLY DEPENDENT ON HOW MUCH COLD ADVECTION TAKES
PLACES IN THE WAKE OF THE THURSDAY-FRIDAY EVENT.
&&
.AVIATION /00Z SATURDAY THROUGH THURSDAY/...
AN ARCTIC FRONT HAD SLIPPED SOUTH THROUGH KALB AS OFF 2330Z...
HEADED TOWARD KPOU. KPOU ASOS HAD RECORDED CLR SKIES...BUT BASED ON
SATELLITE IMAGERY...WHATEVER CLEARING WAS OVERHEAD WILL FILL IN TO
AT LEAST BKN RATHER QUICKLY. NORTHWARD AT THE OTHER TWO AIRPORTS...
ENOUGH DRY AIR HAD INFILTRATED TO RESULT IN A SCT CLOUD NIGHT AS
CIGS ERODE. EASILY LOOKING AT VFR THROUGHOUT THE TAF PERIOD.
SFC WINDS ARE THE FOCUS...WITH DAYTIME NORTHWEST WINDS SUNDAY AROUND
15 KTS...AND GUSTS FREQUENTING THE 20 TO 30 KT RANGE. WITH PRETTY
UNIFORM WINDS THROUGH THE VERTICAL COLUMN...SHEAR IS OF NO CONCERN.
A WEAK REINFORCING COLD FRONT WILL HAVE PRACTICALLY NO MOISTURE
ASSOCIATED WITH IT...SO THIS WILL HAVE NO NOTICEABLE IMPACT AT THE
AIRPORTS ON SUNDAY OTHER THAN TO KEEP THE STRONG NORTHWEST FLOW
GOING.
OUTLOOK...
SUN NGT-MON NGT...VFR...NO SIG WX. BRISK DAYTIME.
TUE-WED NGT...VFR...NO SIG WX.
THU...VFR...CHC PM -RA.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT SEVERAL DAYS. SOME
GAGES WILL CONTINUE TO BE IMPACTED BY ICE ACROSS NORTHERN PORTIONS
OF THE HYDROLOGIC SERVICE AREA.
COLDER AIR WILL BE USHERED IN THE REGION TONIGHT AND SHOULD LEAD
TO SOME ADDITIONAL ICE FORMATION ESPECIALLY ACROSS THE SOUTHERN
ADIRONDACKS...AND AREAS NORTH OF THE MOHAWK RIVER VALLEY.
HOWEVER...TEMPERATURES WILL MODERATE TO ABOVE NORMAL NEXT WEEK.
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...SNYDER
NEAR TERM...BGM/SNYDER
SHORT TERM...SNYDER
LONG TERM...BGM
AVIATION...ELH
HYDROLOGY...IAA
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
400 PM EST Fri Feb 10 2012
...Much colder weather arriving this weekend...
.SYNOPSIS...
20Z water vapor and H4 RUC analysis shows and amplified upper level
pattern consisting of ridging in place from California through much
of the inter-mountain region and downstream troughing covering the
remainder of the CONUS. There area two main features of note
embedded within the main longwave trough. The first is a strong
shortwave diving southward over the upper MS valley that represents
the leading edge of a significant arctic intrusion. The second is
shortwave energy exiting the southern Plains toward the northern
Gulf Coast. This second piece of energy will bring showers to the
area overnight, however is expected to be a low impact event.
Regional radars are showing expanding echoes across the area,
especially in a band from PC beach to Tallahassee, and Valdosta.
Analysis of the 12Z KTLH sounding showed a significant dry layer
above the surface which had been generally preventing these showers
from reaching the surface, but this layer has been moistening and
will now begin to see more and more raindrops reach the surface.
At the surface,
Analysis shows weakening high pressure over the Southeast U.S.
Currently we are under this high "sandwiched" between a weak
inverted surface trough along the Florida East Coast, and an
organizing cold front along the middle/lower MS Valley.
&&
.SHORT TERM (Tonight through Sunday Night)...
Tonight,
A mid/upper level shortwave trough will pivot rapidly eastward along
the northern Gulf coast. Decent swath of synoptic support/QG forcing
ahead of this energy will overspread the area this evening. This
area of forcing is already supporting a large area of showers across
southern LA/MS. Global and hi-res model consensus agrees that this
area of showers will expand rapidly into our region this evening.
The QG forcing will align with upper level jet energy to support the
highest shower concentration over the southern half of the
area...and especially coastal areas eastward through the SE Big
Bend. These areas are highlighted with high end 70% PoPs, and an
argument could easily be made for higher categorical PoPs. PoP
gradient will decrease to the north down to 40-50% up toward KDHN
and KABY. Still do expect some of the showers to reach this far
north, however some guidance members insist that the main area of
showers will be more broken in nature north of the FL border. Even
across the far south...this will be a high PoP...low QPF event, with
highest rainfall amounts likely remaining under 1/4 inch. This will
be a quick hitting event as the last of the organized showers are
expected to be exiting the Suwannee River Valley/I-75 corridor by
around 09Z. Surface based CAPE is essential nil, and even elevated
instability is lacking. Showalter indices are all positive and will
not include thunder mention. Low temperatures in the 40s.
Saturday,
Cold front will quickly pass east of the forecast area Saturday
morning with a much cooler and drier airmass arriving on breezy NW
winds. 850mb temps will fall below 0C over most areas by the end of
the day. Despite the strength of the cold air...excellent diurnal
mixing in the post-frontal environment will keep things seasonable
for afternoon highs. Looking for highs to range from the lower 50s
north and west of a Dothan to Albany line, and range upward to the
lower 60s over the SE Big Bend zones. As mentioned above it will be
quite breezy for those with outdoor plans. NW winds sustained
between 15 to 20 mph with gusts near 25 mph common.
Saturday Night,
The cold air will arrive quickly with the setting of the sun. At
this time expecting temperatures by sunrise on Sunday to be
generally in the upper 20s...with middle 20s possible across the far
north. Current statistical guidance shows lower/middle 20s for
many locations, however, MOS guidance almost always is too low in
these events with respect to the initial advection freeze...and have
taken this bias into account. This will only prevent a hard freeze.
Still anticipate a widespread freeze even right down to the coast.
Combine these temps with a steady northerly breeze and wind chill
reading will reach the upper teens to lower 20s. Will continue to
monitor the situation in case a wind chill advisory becomes
necessary for early Sunday morning.
Sunday/Sunday night,
High pressure will settle southeast from the TN valley toward the
forecast area. The airmass in place and less efficient mixing
will result in a cool day. High temps will struggle into the lower
50s by the late afternoon. The close proximity of the high center
will cause any light afternoon winds will go nearly calm quickly
during the evening. These calm conditions combined with very dry low
levels suggest temps will fall quickly after sunset. Expect to see
normally colder areas fall below freezing potentially by late
evening, and set up a long duration freeze. This appears to be the
night in which hard freeze conditions will be more likely. Low temps
for normally colder areas may drop into the lower 20s...with most
locations away from the immediate coast falling into the middle 20s.
As is usual with radiational cooling...the immediate coast and more
urbanized inland centers (such as downtown Tallahassee) should end
up a few degrees warmer, but still below freezing.
&&
.LONG TERM (Monday through next Friday)...
We`ll see another cold day to start the extended period with
possibly another widespread hard freeze Monday morning mainly east
of the Apalachicola/Chattahoochee Rivers. Surface high pressure will
be centered over the southeast CONUS with nearly zonal flow aloft on
Monday. The high will rapidly move east making way for the next low
pressure system that will bring a weak cold front with rain chances
to the region on Tuesday. This front will stall over or just south
of our FA late Tuesday/early Wednesday and then lift north as a warm
front Wednesday/Wednesday night as a stronger low pressure system
begins to develop over the southern plains. Showers/thunderstorms
will begin to overspread the region during the Thursday/Thursday
night time frame with the front forecast to push into the CWA on
Friday. After below normal temps for Monday, the rest of the
extended period will have above seasonal temps.
&&
.MARINE
A weak area of low pressure will pass south of the forecast waters
this evening. In the wake of this low, winds will increase from the
Northwest later tonight and are forecast to reach advisory levels
Saturday morning. These advisory level conditions will continue
through Sunday morning. A period of gale force gusts is possible
Saturday night and this potential will need to be monitored closely.
Winds and seas will decrease below headline criteria later Sunday
into the early portion of next week.
&&
.Aviation (through 18Z Sat)...Although Vfr conditions should prevail
through the bulk of this Taf period, gradually lowering Vfr level
cigs will predominate the fcst for the remainder of this afternoon
and throughout much of the evening hours. Widespread light rain is
also expected to develop from SW to NE across the terminals, with
possible periods of moderate rain and Mvfr level Vis this evening at
TLH, ECP, and VLD. Although some VFR level clouds could linger
behind the cold front for a while, Saturday should be dominated by
clearing skies, much cooler temps, and very gusty NW winds.
&&
.FIRE WEATHER...
Much cooler and drier air will be building in from the northwest on
Saturday on gusty Northwest winds. This very dry air combined with
sustained 15 mph or greater winds and Dispersions greater than 75
will result in a Red Flag Warning for all of the Florida Big Bend
and Panhandle on Saturday. However, even though relative humidity
values will be extremely low over the same area on Sunday, will hold
off on a Fire Weather Watch until future ERC values can be
determined. Over Southeast Alabama and Southwest and South Central
Georgia, will issue a Fire Weather Watch for Sunday for expected
long durations of relative humidity below 25 percent.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 42 60 27 52 24 / 70 0 0 0 0
Panama City 47 59 31 52 31 / 70 0 0 0 0
Dothan 42 54 27 51 26 / 50 0 0 0 0
Albany 41 56 26 52 25 / 40 0 0 0 0
Valdosta 44 59 27 52 25 / 60 0 0 0 0
Cross City 45 65 28 53 23 / 70 0 0 0 0
Apalachicola 45 60 30 52 29 / 70 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...Fire Weather Watch from Sunday morning through Sunday afternoon
for Coffee-Dale-Geneva-Henry-Houston.
GA...Fire Weather Watch from Sunday morning through Sunday evening
for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-Colquitt-
Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier-Lee-Lowndes-
Miller-Mitchell-Quitman-Randolph-Seminole-Terrell-Thomas-
Tift-Turner-Worth.
FL...Red Flag Warning from 2 PM EST /1 PM CST/ to 7 PM EST /6 PM CST/
Saturday for Calhoun-Central Walton-Coastal Bay-Coastal
Dixie-Coastal Franklin-Coastal Gulf-Coastal Jefferson-
Coastal Taylor-Coastal Wakulla-Gadsden-Holmes-Inland Bay-
Inland Dixie-Inland Franklin-Inland Gulf-Inland Jefferson-
Inland Taylor-Inland Wakulla-Inland Walton-Jackson-
Lafayette-Leon-Liberty-Madison-South Walton-Washington.
GM...Small Craft Advisory from 7 AM Saturday to 10 AM EST Sunday for
Apalachee Bay-Coastal waters From Ochlockonee River to
Apalachicola FL out to 20 NM-Coastal waters from Suwannee
River to Keaton Beach FL out 20 NM-Coastal waters from
Apalachicola to Destin FL out 20 NM-Waters from Suwannee
River to Apalachicola FL from 20 to 60 NM-Waters from
Apalachicola to Destin FL from 20 to 60 NM.
&&
$$
Synopsis/short term/marine...Mroczka
Long Term...Barry
Aviation/Fire Wx...Gould
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
ISSUED BY NATIONAL WEATHER SERVICE COLUMBIA SC
947 AM EST FRI FEB 10 2012
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SMOKE...MOST LIKELY FROM PRESCRIBED BURN ACTIVITY OVER BERKELEY
COUNTY...HAS REACHED AS FAR WEST AS SUMMERVILLE. HAVE INCLUDED
AREAS OF SMOKE IN THE MONCKS CORNER-SUMMERVILLE CORRIDOR THROUGH
MID-MORNING.
10/11Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 MB AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD AIR ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW OVERNIGHT...
CONTRIBUTING TO WIND CHILL VALUES IN THE 12-18 DEGREE RANGE.
RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH
SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
CIGS WILL TEETER ALONG THE MVFR/VFR THRESHOLD THROUGH MID-MORNING
BEFORE FINALLY DROPPING MORE SOLIDLY MVFR. STILL SEEING LOTS OF
TIMING/INTENSITY AND PLACEMENT ISSUES FOR ANY SHOWER ACTIVITY
TODAY. WHILE SHOWERS WILL LIKELY BE AROUND...ESPECIALLY THIS
AFTERNOON...CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO JUSTIFY
A MENTION AT EITHER TERMINAL. CONDITIONS WILL IMPROVE THIS EVENING
AS A COLD FRONT PUSHES OFFSHORE.
EXTENDED AVIATION OUTLOOK...GUSTY WINDS WILL BECOME A CONCERN
SATURDAY WITH LLWS POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD
IMPACT THE TERMINALS AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM
MOVES THROUGH THE AREA.
&&
.MARINE...
THIS AFTERNOON...THE AREA CONTINUES TO BE POSITIONED NEAR A
SHARPENING COASTAL TROUGH ALONG THE FLORIDA EAST COAST. THIS HAS
BROUGHT GENERALLY NORTHEAST WINDS WITH SPEEDS BELOW 15 KT. STILL
EXPECTING NORTHEAST WINDS TO REMAIN IN CONTROL INTO THE EARLY
AFTERNOON HOURS BEFORE VEERING MORE SOUTHERLY LATE THIS AFTERNOON AS
THE COASTAL TROUGH BREAKS DOWN AND A COLD FRONT APPROACHES FROM THE
WEST. BOTH WINDS AND SEAS WILL REMAIN WELL BELOW SMALL CRAFT
ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
656 AM EST FRI FEB 10 2012
...ARCTIC AIR POISED TO MAKE A RETURN TO THE LOWCOUNTRY AND
COASTAL EMPIRE THIS WEEKEND...
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SMOKE...MOST LIKELY FROM PRESCRIBED BURN ACTIVITY OVER BERKELEY
COUNTY...HAS REACHED AS FAR WEST AS SUMMERVILLE. HAVE INCLUDED
AREAS OF SMOKE IN THE MONCKS CORNER-SUMMERVILLE CORRIDOR THROUGH
MID-MORNING.
10/11Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 MB AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD AIR ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW OVERNIGHT...
CONTRIBUTING TO WIND CHILL VALUES IN THE 12-18 DEGREE RANGE.
RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH
SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
CIGS WILL TEETER ALONG THE MVFR/VFR THRESHOLD THROUGH MID-MORNING
BEFORE FINALLY DROPPING MORE SOLIDLY MVFR. STILL SEEING LOTS OF
TIMING/INTENSITY AND PLACEMENT ISSUES FOR ANY SHOWER ACTIVITY
TODAY. WHILE SHOWERS WILL LIKELY BE AROUND...ESPECIALLY THIS
AFTERNOON...CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO JUSTIFY
A MENTION AT EITHER TERMINAL. CONDITIONS WILL IMPROVE THIS EVENING
AS A COLD FRONT PUSHES OFFSHORE.
EXTENDED AVIATION OUTLOOK...GUSTY WINDS WILL BECOME A CONCERN
SATURDAY WITH LLWS POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD
IMPACT THE TERMINALS AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM
MOVES THROUGH THE AREA.
&&
.MARINE...
TODAY...THE REGION IS POSITIONED NORTH OF A SHARPENING COASTAL
TROUGH ALONG THE FLORIDA EAST COAST THIS MORNING. THIS IS YIELDING
A SOLID NORTHEAST WIND REGIME WITH SPEEDS GENERALLY BELOW 15 KT.
NORTHEAST WINDS WILL DOMINATE FOR MUCH OF THE DAY BEFORE VEERING
MORE SOUTHERLY THIS AFTERNOON AS THE COASTAL TROUGH BREAKS DOWN
AND A COLD FRONT APPROACHES FROM THE WEST. BOTH WINDS AND SEAS
WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CLIMATE...
RECORD LOWS FOR SUNDAY FEBRUARY 12...
CHARLESTON AIRPORT.... 12/1973
DOWNTOWN CHARLESTON... 22/1955
SAVANNAH AIRPORT...... 19/1973
RECORD LOWS FOR MONDAY FEBRUARY 13...
CHARLESTON AIRPORT.... 22/1955
DOWNTOWN CHARLESTON... 9/1899
SAVANNAH AIRPORT...... 8/1899
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
642 AM EST FRI FEB 10 2012
...ARCTIC AIR POISED TO MAKE A RETURN TO THE LOWCOUNTRY AND
COASTAL EMPIRE THIS WEEKEND...
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SMOKE...MOST LIKELY FROM PRESCRIBED BURN ACTIVITY OVER BERKELEY
COUNTY...HAS REACHED AS FAR WEST AS SUMMERVILLE. HAVE INCLUDED
AREAS OF SMOKE IN THE MONCKS CORNER-SUMMERVILLE CORRIDOR THROUGH
MID-MORNING.
10/11Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 MB AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS...AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW
OVERNIGHT...CONTRIBUTING TO WIND CHILL VALUES POSSIBLY IN THE
TEENS. RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA
WITH SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
CIGS WILL TEETER ALONG THE MVFR/VFR THRESHOLD THROUGH MID-MORNING
BEFORE FINALLY DROPPING MORE SOLIDLY MVFR. STILL SEEING LOTS OF
TIMING/INTENSITY AND PLACEMENT ISSUES FOR ANY SHOWER ACTIVITY
TODAY. WHILE SHOWERS WILL LIKELY BE AROUND...ESPECIALLY THIS
AFTERNOON...CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO JUSTIFY
A MENTION AT EITHER TERMINAL. CONDITIONS WILL IMPROVE THIS EVENING
AS A COLD FRONT PUSHES OFFSHORE.
EXTENDED AVIATION OUTLOOK...GUSTY WINDS WILL BECOME A CONCERN
SATURDAY WITH LLWS POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD
IMPACT THE TERMINALS AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM
MOVES THROUGH THE AREA.
&&
.MARINE...
TODAY...THE REGION IS POSITIONED NORTH OF A SHARPENING COASTAL
TROUGH ALONG THE FLORIDA EAST COAST THIS MORNING. THIS IS YIELDING
A SOLID NORTHEAST WIND REGIME WITH SPEEDS GENERALLY BELOW 15 KT.
NORTHEAST WINDS WILL DOMINATE FOR MUCH OF THE DAY BEFORE VEERING
MORE SOUTHERLY THIS AFTERNOON AS THE COASTAL TROUGH BREAKS DOWN
AND A COLD FRONT APPROACHES FROM THE WEST. BOTH WINDS AND SEAS
WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
406 AM EST FRI FEB 10 2012
...ARCTIC AIR POISED TO MAKE A RETURN TO THE LOWCOUNTRY AND
COASTAL EMPIRE THIS WEEKEND...
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL LINGER OFF THE COAST TODAY. A COLD
FRONT WILL PUSH OFFSHORE LATE TONIGHT INTO EARLY SATURDAY AND BE
FOLLOWED BY A SECONDARY REINFORCING COLD FRONT SATURDAY NIGHT.
COLD HIGH PRESSURE WILL BUILD FROM THE WEST AND PERSIST THROUGH
EARLY NEXT WEEK. ANOTHER STORM SYSTEM COULD AFFECT THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
PRESCRIBED BURN ACTIVITIES ARE PRODUCING AREAS OF SMOKE ACROSS
PORTIONS OF BERKELEY COUNTY EARLY THIS MORNING. VISIBILITIES HAVE
BEEN AS LOW AS 2 MILES AT TIMES AT THE KMKS AWOS...BUT THE COUNTY
WARNING POINT INDICATES VISIBILITIES HAVE BEEN LOWER AT TIMES.
WILL CONTINUE TO HIGHLIGHT AREAS OF SMOKE IN OUR GRIDDED AND TEXT
FORECASTS...BUT CONDITIONS DO NOT SUPPORT DENSE SMOKE ADVISORY
CRITERIA ATTM.
10/08Z SURFACE ANALYSIS DEPICTED WEAK RIDGING ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH SUBTLE COASTAL TROUGHING
SHARPENING UP ALONG THE FLORIDA EAST COAST. THE HEAD OF THE
COASTAL TROUGH IS CURRENTLY POSITIONED JUST EAST OF JACKSONVILLE
FLORIDA WITH NORTHEAST WINDS NOTED ACROSS THE COASTAL WATERS
BETWEEN LONG BAY AND SAINT SIMMONS ISLAND. A PRONOUNCED MID-LEVEL
CLOUD DECK IS STEADILY THICKENING AND EXPANDING INLAND IN RESPONSE
TO INTENSIFYING 290-295K ISENTROPIC ASSENT ATOP THE INLAND RIDGE
AND NEARBY COASTAL TROUGH. CONDENSATION PRESSURE DEFICITS /CPD/
REMAIN FAIRLY HIGH BUT ARE PROGGED TO QUICKLY DROP BELOW 20 NM
LATER THIS MORNING PER THE LATEST RUC ISENTROPIC 4-PANELS.
WITH SUCH HIGH CPD/S IN PLACE...MOST OF THE ISENTROPIC ASSENT
WILL CONTINUE TO CONTRIBUTE TO THICKENING CLOUD COVER VERSUS
SHOWER PRODUCTION FOR THE NEXT FEW HOURS...BUT THIS SHOULD CHANGE
BY MID-LATE MORNING AS VALUES DROP BELOW 20 NM AND MORE
SYNOPTICALLY DRIVEN DYNAMICS SOME INTO PLACE. THE BEST CHANCES
FOR MEASURABLE RAINFALL TODAY WILL BE FOUND ROUGHLY ALONG AND EAST
OF INTERSTATE 95 AS THIS WILL BE WHERE THE MOST FAVORABLE
JUXTAPOSITION OF LOW- LEVEL MOISTURE AND UVV/S WILL OCCUR THROUGH
EARLY EVENING. WE CONTINUE TO FAVOR THE DRIER 10/00Z GFS SOLUTION
WITH A HEALTHY BLEND FROM THE LATEST NSSL-WRF AS THE 10/00Z NAM
STILL APPEARS TOO AGGRESSIVE WITH THE DEVELOPMENT OF THE COASTAL
TROUGH/SURFACE LOW WITHIN THE HIGHLY SHEARED H5 VORTICITY PATTERN.
PLAN TO INCREASE POPS TO 40-50 PERCENT ALONG AND EAST OF I-95 FOR
THIS AFTERNOON WITH POPS NO HIGHER THAN 20-30 PERCENT ACROSS THE
FAR WESTERN/INTERIOR ZONES. RAINFALL AMOUNTS WILL RANGE FROM A
TRACE WELL INLAND TO POSSIBLY AS HIGH AS 0.10-0.20 INCHES ACROSS
CHARLESTON AND EASTERN BERKELEY COUNTIES WHICH WILL DO LITTLE TO
IMPROVE THE RAPIDLY EXPANDING AREAS OF EXCEPTIONAL DROUGHT.
HIGHS WILL RANGE FROM THE LOWER-MID 60S EXCEPT ACROSS PARTS OF THE
FAR SOUTHERN AREA FROM SAVANNAH SOUTH TO DARIEN AND LUDOWICI WHERE
MID 60S ARE LIKELY.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
TONIGHT...ISOLATED-SCATTERED LIGHT RAIN SHOWERS WILL GRADUALLY
END FROM WEST-EAST THIS EVENING AS A COLD FRONT MOVES ACROSS THE
REGION. THE FRONT IS EXPECTED TO BE WELL OFFSHORE BY SUNRISE
SATURDAY AS LOW PRESSURE RAPIDLY DEEPENS OFF THE MIDDLE ATLANTIC
COAST. TEMPERATURES WILL INITIALLY BE HELD UP WITHIN THE WARM
SECTOR AND WILL BEGIN TO STEADILY FALL IN ITS WAKE AS COLD AIR
ADVECTION ENSUES. LOWS SATURDAY MORNING WILL RANGE FROM THE UPPER
30S/NEAR 40 IN THE MILLEN-SYLVANIA-ALLENDALE CORRIDOR TO THE UPPER
40S ALONG THE COAST.
SATURDAY...SURFACE LOW PRESSURE WILL LIFT OFF THE VIRGINIA AND
NORTH CAROLINA COASTLINE BY DAYBREAK SATURDAY...WHILE SHORTWAVE
ENERGY TRAVERSES THE FORECAST AREA AND PROVIDES THE FINAL PUSH OF
THE COLD FRONT OFFSHORE. ANY ASSOCIATED SHOWER ACTIVITY WILL BE
QUICKLY SHIFTING INTO THE WATERS SATURDAY MORNING...AS A MUCH
DRIER AIR MASS FOLLOWS IN THE WAKE OF THE FRONT. THE FIRST WAVE OF
COLD ADVECTION WILL SUPPRESS HIGH TEMPERATURES IN THE UPPER 50S
SATURDAY AFTERNOON...WITH BREEZY CONDITIONS UNDER AN INTENSIFYING
LOW LEVEL JET AND TIGHTENED PRESSURE GRADIENT.
SATURDAY NIGHT...MORE SIGNIFICANT COLD ADVECTION WILL OCCUR
OVERNIGHT...AS THE AXIS OF THE BROAD UPPER TROUGH CROSSES THE EAST
COAST. A SECONDARY DRY FRONT WILL ALSO PASS THROUGH THE
REGION...LEADING AN IMPRESSIVE WAVE OF ARCTIC AIR INTO THE
SOUTHEAST STATES. TEMPERATURES WILL RAPIDLY FALL INTO THE 20S FOR
MANY LOCATIONS...AS ADVECTION PUSHES CONSIDERABLE COLD AIR TOWARD
THE COASTLINE. A 30 TO 40 KT LOW LEVEL JET UNDERNEATH A NEARLY 150
KT UPPER JET WILL MAINTAIN DECENT NORTHWEST FLOW
OVERNIGHT...CONTRIBUTING TO WIND CHILL VALUES POSSIBLY IN THE
TEENS. RESIDENTS OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA
WITH SENSITIVE OUTDOOR VEGETATION WILL WANT TO TAKE THE PROPER
PRECAUTIONS. SINCE THE FROST/FREEZE PROGRAM HAS YET TO OFFICIALLY
BEGIN...FROST ADVISORIES OR FREEZE WATCHES/WARNINGS WILL NOT BE
ISSUED FOR THIS EVENT. HOWEVER...WILL CONTINUE TO HIGHLIGHT THE
COLD WEATHER IN THE HAZARDOUS WEATHER OUTLOOK AND WILL CONSIDER
ISSUING SPECIAL WEATHER STATEMENTS AS THE COLD SPELL APPROACHES.
SUNDAY...WITH COLD HIGH PRESSURE IN PLACE...TEMPERATURES ON SUNDAY
WILL BE DRAMATICALLY LOWER COMPARED TO PREVIOUS DAYS. EXPECT
TEMPERATURES TO BE SUPPRESSED IN THE UPPER 40S TO AROUND 50
DEGREES DESPITE ABUNDANT SUNSHINE. LOW TEMPERATURES ON SUNDAY
NIGHT COULD EVEN BE A DEGREE OR TWO COLDER THAN SATURDAY
NIGHT...AS RADIATIONAL COOLING WILL BE MORE EFFICIENT UNDER
LIGHTER WINDS AND CLEAR SKIES.
MONDAY...EXPECT A GRADUAL MODERATION IN TEMPERATURES TO BEGIN ON
MONDAY...AS SURFACE HIGH PRESSURE STEADILY TRACKS EAST TOWARD THE
COASTLINE AND HEIGHTS ALOFT BEGIN TO SUBTLY INCREASE. LIGHT WINDS
COULD ACTUALLY SHIFT AROUND TO THE SOUTH AND EFFECTIVELY SHUT OFF
ANY LINGERING COLD ADVECTION. HIGH TEMPERATURES ON MONDAY WILL
REACH THE UPPER 50S.
LAKE WINDS...STRONG WINDS ARE EXPECTED TO DEVELOP ON LAKE MOULTRIE
FOLLOWING THE PASSAGE OF A COLD FRONT SATURDAY AND THEN INCREASE
FURTHER BEHIND A REINFORCING COLD FRONT SATURDAY NIGHT. A LAKE
WIND ADVISORY WILL LIKELY BE NEEDED SATURDAY AFTERNOON THROUGH
SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO TRACK EAST INTO THE ATLANTIC
WATERS LATE MONDAY THROUGH TUESDAY. SHORTWAVE ENERGY EMBEDDED
WITHIN NEARLY ZONAL FLOW ALOFT WILL SHIFT INTO THE FORECAST AREA
BY TUESDAY AFTERNOON...ACCOMPANIED BY A DEVELOPING SURFACE FRONT.
THIS SYSTEM APPEARS TO HAVE A DECENT TAP INTO DEEP MOISTURE DURING
ITS APPROACH ON TUESDAY...WITH FORECAST MODELS SHOWING EVIDENCE OF
STRONG WARM ADVECTION AND SOUTHWEST FLOW LIKELY TAPPING INTO GULF
MOISTURE. WILL THUS CONTINUE TO CARRY RAIN CHANCES 30 PERCENT OR
LESS LATE MONDAY NIGHT THROUGH TUESDAY NIGHT...ACCOUNTING FOR SOME
UNCERTAINTY IN THE TIMING AND TRACK OF THE FRONT.
MEDIUM RANGE FORECAST MODELS ARE INDICATING LITTLE TO NO COLD
ADVECTION BEHIND THE FRONT...AND TEMPERATURES MID TO LATE WEEK
COULD ACTUALLY REMAIN ABOVE SEASONAL NORMALS AS THE WEATHER
PATTERN APPEARS MORE UNSETTLED. CONFIDENCE IN FORECAST DETAILS
FOLLOWING THE TUESDAY FRONTAL SYSTEM IS QUITE LOW...AND PREFER TO
LEAN TOWARD A BLEND OF GUIDANCE AND PERSISTENCE AT THIS TIME.
WILL KEEP POPS BELOW 15 PERCENT FOR WEDNESDAY...THEN REINTRODUCE
RAIN CHANCES THURSDAY AND FRIDAY AS ANOTHER SURFACE WAVE/FRONTAL
SYSTEM COULD IMPACT THE SOUTHEAST STATES LATE WEEK.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
LOW-END VFR CIGS HAVE MOVED INTO THE KCHS-KSAV CORRIDOR ALONG THE
LEADING EDGE OF ISENTROPIC ASSENT. EXPECT LOW-END VFR OR HIGH-END
MVFR CIGS TO DOMINATE THROUGH SUNRISE WITH INCREASING
PROBABILITIES FOR PREVAILING MVFR CIGS THEREAFTER. SHOWER ACTIVITY
WILL INCREASE LATER THIS MORNING WITH THE GREATEST COVERAGE
OCCURRING EAST OF I-95 THIS AFTERNOON. TIMING AND INTENSITY
UNKNOWN SUPPORT KEEPING SHOWERS OUT OF BOTH TAFS SITES
ATTM...HOWEVER AT SOME POINT MVFR VSBYS ARE EXPECTED IN SHOWERS...
ESPECIALLY AT KCHS.
EXTENDED AVIATION OUTLOOK...MVFR CIGS AND/OR VSBYS COULD AFFECT
THE TERMINALS THROUGH FRIDAY NIGHT...AS A WAVE OF LOW PRESSURE
LIFTS WELL OFF THE COAST OF THE SOUTHEAST UNITED STATES. IN
ADDITION...GUSTY WINDS WILL BECOME A CONCERN SATURDAY...WITH LLWS
POSSIBLE SATURDAY NIGHT. MVFR CONDITIONS COULD IMPACT THE TERMINALS
AGAIN ON TUESDAY...AS ANOTHER STORM SYSTEM MOVES THROUGH THE AREA.
&&
.MARINE...
TODAY...THE REGION IS POSITIONED NORTH OF A SHARPENING COASTAL
TROUGH ALONG THE FLORIDA EAST COAST THIS MORNING. THIS IS YIELDING
A SOLID NORTHEAST WIND REGIME WITH SPEEDS GENERALLY BELOW 15 KT.
NORTHEAST WINDS WILL DOMINATE FOR MUCH OF THE DAY BEFORE VEERING
MORE SOUTHERLY THIS AFTERNOON AS THE COASTAL TROUGH BREAKS DOWN
AND A COLD FRONT APPROACHES FROM THE WEST. BOTH WINDS AND SEAS
WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY THRESHOLDS.
TONIGHT...THE COLD FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND WILL EXIT INTO THE GULF STREAM BY SUNRISE SATURDAY.
THIS INITIAL BOUT OF POST-FRONTAL COLD AIR ADVECTION LOOKS FAIRLY
WEAK...WHICH WILL ONLY YIELD A MODEST INCREASE IN BOTH WINDS AND
SEAS FOR MUCH OF THE TONIGHT PERIOD. SPEEDS WILL BE STEADILY
RAMPING UP HOWEVER WITH THE GREATEST CHANCES FOR SMALL CRAFT
ADVISORY CONDITIONS LIKELY HOLDING OFF UNTIL AFTER SUNRISE.
SATURDAY THROUGH TUESDAY...A COLD FRONT WILL PUSH THROUGH THE
MARINE AREA SATURDAY MORNING...RAPIDLY FOLLOWED BY A SECONDARY
REINFORCING FRONT SATURDAY NIGHT. ALL MARINE ZONES WILL BE SOLIDLY
WITHIN SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY...AS COLD
ADVECTION INTENSIFIES AND TAPS INTO IMPRESSIVE LOW LEVEL WINDS.
FREQUENT GALE FORCE GUSTS ARE ALSO POSSIBLE FOR THE WARMER WATERS
MAINLY BEYOND 20 NM...WHERE MIXING WILL BE MAXIMIZED. A GALE WATCH
MAY BE NEEDED FOR THE GEORGIA OFFSHORE WATERS LATER TODAY. SLOWLY
IMPROVING CONDITIONS ARE EXPECTED ON SUNDAY...AS THE COLD AIR
ADVECTION/TIGHT PRESSURE GRADIENT REGIME BEGINS TO WEAKEN. AT THIS
TIME...IT APPEARS THAT CONDITIONS WILL DROP BELOW ADVISORY LEVELS
ACROSS THE NEARSHORE WATERS AROUND NOON ON SUNDAY...WITH SEAS MOST
LIKELY REMAINING AT OR ABOVE CRITERIA ACROSS THE OUTER GEORGIA
WATERS THROUGH LATE SUNDAY AFTERNOON OR EARLY SUNDAY EVENING.
CONDITIONS WILL CONTINUE TO IMPROVE SUNDAY NIGHT THROUGH MONDAY
NIGHT...THEN POSSIBLY GO DOWNHILL AGAIN TUESDAY AS A LOW PRESSURE
SYSTEM IMPACTS THE SOUTHEAST STATES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
218 PM CST FRI FEB 10 2012
.DISCUSSION...
120 PM CST
THE ARCTIC FRONT IS SWINGING SOUTH INTO NORTHEAST IL EARLY THIS
AFTERNOON. IMMEDIATELY ALONG THIS IS AN ENHANCED AREA OF SNOWFALL
THAT HAS A HISTORY OF REDUCING VISIBILITY TO ONE QUARTER MILE OR
LESS. THIS IS CORRELATED TO STEEP LOW-LEVEL LAPSE RATES AND STRONG
CONVERGENCE. SHORT TERM GUIDANCE INDICATES THIS WILL CONTINUE TO
PROPAGATE SOUTH THROUGH THE CHICAGO METRO AREA. SNOWFALL BEHIND
THIS WITHIN THE MID-LEVEL FORCING AND CONTINUED STEEP LOW-LEVEL
LAPSE RATES HAS ALSO BEEN MODERATE IN INTENSITY. THIS HAS SHOWN
SIGNS OF BEING LAKE ENHANCED AT TIMES NEAR THE LAKE SHORE...WITH
THUNDER REPORTED EARLIER IN FOND DU LAC. THIS AREA SHOULD ALSO
HOLD TOGETHER CONTINUING SNOWFALL ACROSS CHICAGO AFTER THE
IMMEDIATE FRONTAL PASSAGE...AND LIKELY INTO THE LATE AFTERNOON
RUSH HOUR. MORE TRULY LAKE EFFECT SNOW IS EXPECTED TO ALSO DEVELOP
INTO NORTHEAST IL LATE THIS AFTERNOON AND EARLY THIS EVENING
BEFORE ESTABLISHING ITSELF INTO FAR SOUTHEAST COOK COUNTY AND
NORTHWEST INDIANA.
MTF
//PREV DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CIGS DOWN BLO 1000FT AGL...WILL HOVER ARND THIS HEIGHT THRU
REMAINDER OF THIS AFTN EARLY EVENING.
* NORTHWEST WINDS VEER NORTH. A PERIOD OF TIME WINDS MAY BLEED
NORTHEAST FOR A TEMPO BETWEEN 20-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 20Z...
LATEST RADAR REFLECTIVITY CONCERNING PLACEMENT OF MOST INTENSE
SNOW WAS SLIDING SOUTH ACROSS NORTHERN COOK COUNTY...WHICH WAS
IMPACTING ORD AND EXPECTED TO IMPACT MDW WITHIN THE NEXT 30-45
MINUTES. THIS WAS BRINGING VSBYS DOWN FOR A TEMPO TO 1/4SM AND
+SN. ON BACK SIDE OF THIS SLUG OF POTENT SNOW VSBYS SHUD COME BACK
UP TO ARND 1SM WITH -SN. CIGS HAVE ALSO REDUCED TO ARND
VV007...ALTHOUGH ANTICIPATE THIS TO BE SHORT LIVED AND CIGS SHUD
HOVER ARND 800-1000FT AGL. LAKE EFFECT SNOW WAS ALSO FORMING
ACROSS EAST CENTRAL WISCONSIN AND EXPECTED TO CLIP ORD/MDW LATER
THIS AFTN. WINDS HAVE ALSO PUSHED NORTHEAST AT 010-020...AGAIN
EXPECTED TO BE SHORT-LIVED AND COME BACK TO A 350-360 DIRECTION.
SPEEDS WILL COTNINUE TO INCREAS AS WELL TO ARND SUSTAINED 15-18KT
WITH OCCASIONAL GUSTS TO 25-28KT. VISIBLE IMAGERY WAS ALSO
INDICATING SOME CONVECTIVE ELEMENTS TO THE CLOUDS...WHICH
INDICATES SOME STRONG LIFT AND POSSIBLE THUNDER. ALTHOUGH THIS IS
A REMOTE POSSIBILITY...IT SHOULD BE NOTED. AS THIS COULD ENHANCE
SNOW OVER A FEW AIRFIELDS.
PREVIOUS DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
156 PM CST
THE MAIN CONCERNS CONTINUE TO FOCUS ON THE STRONG WINDS ACROSS LAKE
MICHIGAN TONIGHT INTO SATURDAY. THE STRONG SURFACE COLD FRONT IS
MOVING ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN EARLY THIS
AFTERNOON. I EXPECT NORTHERLY GALE FORCE WINDS AROUND 35 KNOTS IN
THE WAKE OF THIS FRONT. AS VERY COLD AIR CONTINUES TO SPILL OVER THE
LAKE THIS EVENING...A FAVORABLE THERMODYNAMIC SETUP WILL OCCUR FOR A
BANDS OF INTENSE LAKE EFFECT SNOW TO DEVELOP. THERE IS ALSO A GOOD
POSSIBILITY THAT AS SOME AREAS ACROSS THE SOUTHERN END OF THE LAKE
MAY SEE GALES INCREASE TO 40 KT FOR A PERIOD TONIGHT AS THESE
CONVERGENT BANDS OF SNOW DEVELOP. THESE STRONG WINDS WILL LIKELY
ALSO AFFECT THE INDIANA NEAR SHORE WATERS.
WINDS WILL ABATE SOME ON SATURDAY. HOWEVER...THE PRESSURE GRADIENT
WILL REMAIN FAIRLY TIGHT ACROSS THE LAKE AS HIGH PRESSURE DROPS OUT
OF SOUTHERN CANADA AND BUILDS ACROSS THE LOWER AND MIDDLE MISSOURI
RIVER VALLEY. THEREFORE...EXPECT NORTHWEST WINDS TO 30 KT TO
CONTINUE ON SATURDAY AND SATURDAY NIGHT. THIS SURFACE HIGH WILL
BUILD EASTWARD ACROSS THE OHIO VALLEY ON SUNDAY AND SUNDAY NIGHT.
ONCE THIS OCCURS THE WINDS WILL BECOME WEST SOUTHWESTERLY BY MONDAY.
WIND SPEEDS WILL DIMINISH INTO MONDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002 UNTIL 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL 10 AM SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...10 AM SATURDAY TO
2 PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 PM CST FRI FEB 10 2012
.DISCUSSION...
120 PM CST
THE ARCTIC FRONT IS SWINGING SOUTH INTO NORTHEAST IL EARLY THIS
AFTERNOON. IMMEDIATELY ALONG THIS IS AN ENHANCED AREA OF SNOWFALL
THAT HAS A HISTORY OF REDUCING VISIBILITY TO ONE QUARTER MILE OR
LESS. THIS IS CORRELATED TO STEEP LOW-LEVEL LAPSE RATES AND STRONG
CONVERGENCE. SHORT TERM GUIDANCE INDICATES THIS WILL CONTINUE TO
PROPAGATE SOUTH THROUGH THE CHICAGO METRO AREA. SNOWFALL BEHIND
THIS WITHIN THE MID-LEVEL FORCING AND CONTINUED STEEP LOW-LEVEL
LAPSE RATES HAS ALSO BEEN MODERATE IN INTENSITY. THIS HAS SHOWN
SIGNS OF BEING LAKE ENHANCED AT TIMES NEAR THE LAKE SHORE...WITH
THUNDER REPORTED EARLIER IN FOND DU LAC. THIS AREA SHOULD ALSO
HOLD TOGETHER CONTINUING SNOWFALL ACROSS CHICAGO AFTER THE
IMMEDIATE FRONTAL PASSAGE...AND LIKELY INTO THE LATE AFTERNOON
RUSH HOUR. MORE TRULY LAKE EFFECT SNOW IS EXPECTED TO ALSO DEVELOP
INTO NORTHEAST IL LATE THIS AFTERNOON AND EARLY THIS EVENING
BEFORE ESTABLISHING ITSELF INTO FAR SOUTHEAST COOK COUNTY AND
NORTHWEST INDIANA.
MTF
//PREV DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIGS DOWN TO ARND 1500FT AGL...WILL CONTINUE TO LOWER AS ADDTL SNOW
DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
156 PM CST
THE MAIN CONCERNS CONTINUE TO FOCUS ON THE STRONG WINDS ACROSS LAKE
MICHIGAN TONIGHT INTO SATURDAY. THE STRONG SURFACE COLD FRONT IS
MOVING ACROSS THE SOUTHERN TIP OF LAKE MICHIGAN EARLY THIS
AFTERNOON. I EXPECT NORTHERLY GALE FORCE WINDS AROUND 35 KNOTS IN
THE WAKE OF THIS FRONT. AS VERY COLD AIR CONTINUES TO SPILL OVER THE
LAKE THIS EVENING...A FAVORABLE THERMODYNAMIC SETUP WILL OCCUR FOR A
BANDS OF INTENSE LAKE EFFECT SNOW TO DEVELOP. THERE IS ALSO A GOOD
POSSIBILITY THAT AS SOME AREAS ACROSS THE SOUTHERN END OF THE LAKE
MAY SEE GALES INCREASE TO 40 KT FOR A PERIOD TONIGHT AS THESE
CONVERGENT BANDS OF SNOW DEVELOP. THESE STRONG WINDS WILL LIKELY
ALSO AFFECT THE INDIANA NEAR SHORE WATERS.
WINDS WILL ABATE SOME ON SATURDAY. HOWEVER...THE PRESSURE GRADIENT
WILL REMAIN FAIRLY TIGHT ACROSS THE LAKE AS HIGH PRESSURE DROPS OUT
OF SOUTHERN CANADA AND BUILDS ACROSS THE LOWER AND MIDDLE MISSOURI
RIVER VALLEY. THEREFORE...EXPECT NORTHWEST WINDS TO 30 KT TO
CONTINUE ON SATURDAY AND SATURDAY NIGHT. THIS SURFACE HIGH WILL
BUILD EASTWARD ACROSS THE OHIO VALLEY ON SUNDAY AND SUNDAY NIGHT.
ONCE THIS OCCURS THE WINDS WILL BECOME WEST SOUTHWESTERLY BY MONDAY.
WIND SPEEDS WILL DIMINISH INTO MONDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002 UNTIL 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
124 PM CST FRI FEB 10 2012
.DISCUSSION...
120 PM CST
THE ARCTIC FRONT IS SWINGING SOUTH INTO NORTHEAST IL EARLY THIS
AFTERNOON. IMMEDIATELY ALONG THIS IS AN ENHANCED AREA OF SNOWFALL
THAT HAS A HISTORY OF REDUCING VISIBILITY TO ONE QUARTER MILE OR
LESS. THIS IS CORRELATED TO STEEP LOW-LEVEL LAPSE RATES AND STRONG
CONVERGENCE. SHORT TERM GUIDANCE INDICATES THIS WILL CONTINUE TO
PROPAGATE SOUTH THROUGH THE CHICAGO METRO AREA. SNOWFALL BEHIND
THIS WITHIN THE MID-LEVEL FORCING AND CONTINUED STEEP LOW-LEVEL
LAPSE RATES HAS ALSO BEEN MODERATE IN INTENSITY. THIS HAS SHOWN
SIGNS OF BEING LAKE ENHANCED AT TIMES NEAR THE LAKE SHORE...WITH
THUNDER REPORTED EARLIER IN FOND DU LAC. THIS AREA SHOULD ALSO
HOLD TOGETHER CONTINUING SNOWFALL ACROSS CHICAGO AFTER THE
IMMEDIATE FRONTAL PASSAGE...AND LIKELY INTO THE LATE AFTERNOON
RUSH HOUR. MORE TRULY LAKE EFFECT SNOW IS EXPECTED TO ALSO DEVELOP
INTO NORTHEAST IL LATE THIS AFTERNOON AND EARLY THIS EVENING
BEFORE ESTABLISHING ITSELF INTO FAR SOUTHEAST COOK COUNTY AND
NORTHWEST INDIANA.
MTF
&&
.PREV DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIGS DOWN TO ARND 1500FT AGL...WILL CONTINUE TO LOWER AS ADDTL SNOW
DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001 UNTIL 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002 UNTIL 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...INDIANA NEARSHORE WATERS UNTIL NOON SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1202 PM CST FRI FEB 10 2012
.DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CIGS DOWN TO ARND 1500FT AGL...WILL CONTINUE TO LOWER AS ADDTL SNOW
DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VERY DIFFICULT FLYING CONDITIONS FOR NORTHEAST ILLINOIS/NORTHWEST
INDIANA AIRFIELDS AS A FRONTAL BOUNDARY CONTINUES TO SLIDE
SOUTHEAST ACROSS THE AREA AND MUCH COLDER AIR FILTERS IN BEHIND
THIS BOUNDARY. WINDS WILL ALSO BE TURNING FROM WEST TO
NORTH...THEN DIRECTLY BEHIND THE FRONT WINDS MAY BRIEFLY TURN
NORTHEASTERLY. AS SNOW CONTINUES TO OVERSPREAD THE AREA...CIGS
WILL STEADILY LOWER. EXPECT CIGS TO HOVER ARND 1500FT AGL...THEN
LOWER TO NEAR IFR CONDS. FOR AIRFIELDS CLOSER TO LAKE MICHIGAN
CIGS MAY GO FURTHER DOWN TOWARDS LIFR. THE MAIN CONCERN WILL BE
GYY WHERE CIGS COULD GO DOWN THIS EVENING/OVERNIGHT TO ARND 200FT
AGL. QUICK BURSTS OF SNOW WILL BRING VSBYS DOWN AS WELL...LIMITING
VSBYS TO ARND 1SM POSSIBLY AS LOW AS 1/2SM FOR ORD/MDW/DPA. RFD
WILL CONTINUE TO SEE VSBYS ARND 2SM AS THE POTENCY OF THE SNOW
WILL NOT BE AS GREAT...AND THE FOCUS WILL REMAIN EAST.
AS WINDS TURN NORTH OR BETWEEN 340-350 DEG...THE FOCUS OF THE SNOW
WILL TURN TOWARDS NORTHWEST INDIANA. THIS WILL BRING IMPROVING
CONDS TO NORTHEAST IL AIRFIELDS...AND POSSIBLY BRING AND END TO
THE SNOW ARND 3Z SAT. WINDS WILL CONTINUE TO BE GUSTY AT TIMES
FROM THE NORTHWEST THROUGH MUCH OF SAT...AS A STRONG AREA OF HIGH
PRESSURE BUILDS IN TO THE WEST. THIS WILL ALSO AID IN PUSHING EAST
THE LOW LEVEL MOISTURE/CLOUDS...AND SHOULD SEE CIGS RISE TO VFR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001...3 PM FRIDAY TO 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002...3 PM FRIDAY TO 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...3 PM FRIDAY TO NOON
SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1023 AM CST FRI FEB 10 2012
.DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
//PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CIGS DOWN TO ARND 1600FT AGL...WILL CONTINUE TO LOWER AS ADDTL
SNOW DEVELOPS.
* WEST WINDS WILL EVENTUALLY VEER NORTH. POSSIBLY FOR A PERIOD OF
TIME WINDS MAY BLEED NORTHEAST FOR A TEMPO BETWEEN 19-22Z.
* SNOW MAY REDUCE VSBYS DOWN TO ARND 1SM...WITH SOME OF THE MORE
POTENT BURSTS REDUCING SNOW TO ARND 1/2SM.
BEACHLER
//DISCUSSION...UPDATED 12Z...
A LOW PRESSURE SYSTEM PASSES TO THE NORTH TODAY...BUT ITS COLD
FRONT WILL PASS THROUGH THE REGION LATE THIS MORNING THROUGH EARLY
THIS AFTERNOON. LIGHT SNOW SHOWERS WILL SPREAD ACROSS THE REGION
AND WINDS WILL TURN NORTHERLY BEHIND THE FRONT. EXPECTING MVFR
VSBY IN THE LIGHT SNOW SHOWERS. MODELS INDICATE THERE WILL BE
LAKE ENDUCED LIFT AFFECTING REACHING AS FAR INWARD AS ORD AND MDW.
THE ENHANCED LIFT LOOKS LIKE IT WILL BE BELOW THE IDEAL SNOW
GROWTH ZONE...WHICH WILL RESULT IN VERY FINE SNOW FLAKES. WHILE
NOT EXPECTING MORE THAN 1 TO 2 INCHES OF TOTAL SNOW ACCUMULATION
TODAY FOR MDW AND ORD...AN ABUNDANCE OF SMALL SNOW FLAKES COMBINED
WITH WIND GUSTS UP TO 30 KT WILL RESULT IN IFR TO LIFR VSBYS THIS
AFTERNOON.
WINDS WILL TURN MORE NORTHWESTERLY LATE THIS AFTERNOON...WHICH
WILL PUSH THE SNOW BAND INTO NORTHWEST INDIANA. GYY WILL BE
HARDEST HIT BY THE SNOW TODAY...WITH AT LEAST 5 TO 7 INCHES OF
SNOW POSSIBLE. MORE SNOW COULD ACCUMULATE DEPENDING ON HOW LONG
THE LAKE EFFECT SNOW BAND RESIDES OVER GYY. LUCKILY...EXPECTING
THE WORST OF THE SNOW TO OCCUR AFTER OPERATING HOURS.
CONDITIONS WILL RAPIDLY IMPROVE BEHIND THE SNOW...WITH VFR
EXPECTED BY SATURDAY MORNING AT ALL TERMINALS EXCEPT GYY. GUSTY
NORTHWEST WINDS WILL CONTINUE THROUGH TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN CIGS FORECAST.
* MEDIUM CONFIDENCE ON WIND CHANGE FROM W TO N.
* LOW CONFIDENCE IN WINDS BENDING NE.
* HIGH CONFIDENCE IN WIND GUSTS.
* HIGH CONFIDENCE IN SNOW AND BURSTS OF SNOW.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001...3 PM FRIDAY TO 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002...3 PM FRIDAY TO 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM
SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...3 PM FRIDAY TO NOON
SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1007 AM CST FRI FEB 10 2012
.DISCUSSION...
1005 AM CST
GOING FORECAST FOR THE SNOW AMOUNTS...IMPACTS...AND HEADLINES THIS
AFTERNOON AND TONIGHT LOOK IN GOOD SHAPE AT THIS TIME. DID MAKE
SOME ADJUSTMENTS TO THE CHICAGOLAND AREA TO ADD PERIODS OF HEAVY
SNOW AND SOME BLOWING SNOW THIS AFTERNOON.
UPSTREAM WAVE ON SATELLITE CHANNELS IS REALLY LOOKING
IMPRESSIVE...WITH RADAR MOSAIC SHOWING AN ENHANCED AREA ALONG AND
JUST BEHIND THE ARCTIC FRONT LINING UP WELL WITH LOW-LEVEL
FRONTOGENSIS AND LAPSE RATES. THE NORTHERLY WINDS PICK UP RAPIDLY
BEHIND THE FRONT WITH GUSTS TO 30 MPH...AND MULTIPLE OBSERVATIONS
HAVE INDICATED ONE QUARTER MILE VISIBILITY /EVEN BRIEFLY A ZERO AT
KOSH/. MULTIPLE SHORT TERM GUIDANCE HAVE A GOOD INITIALIZATION ON
THIS AND THE FORCING...BRINGING THE AREA SOUTHWARD NEARLY INTACT
THROUGH THE HEART OF CHICAGO THIS AFTERNOON...NAMELY BETWEEN 2 AND
5 PM. ENHANCEMENT HAS BEEN SEEN AHEAD OF THIS IN LAKE AND MCHENRY
COUNTIES...LIKELY ROOTED HIGHER THAN THE FORCING SEEN UPSTREAM IN
WI. SIMILAR PRE-FRONTAL DEVELOPMENT IS ALSO LIKELY TO OCCUR AS THE
WAVE SHIFTS SOUTH...SO HAVE BROUGHT HIGHER POPS SOUTH QUICKER.
HAVE BASICALLY GONE NEAR 100 POPS FOR CHICAGO WHERE IT LOOKS
DEFINITE TO SNOW...AND ADDED MENTION OF BLOWING SNOW COINCIDENT
WITH THE FRONTAL PASSAGE. EARLY ANALYSIS OF THE 12Z GUIDANCE SHOWS
THAT THE NAM HAS SHIFTED JUST SLIGHTLY WEST AND THE HRRR HAS
INITIAL SETUP INTO SOUTHEAST COOK COUNTY AS WELL. WILL LOOK AT
THIS FURTHER TO SEE IF SNOWFALL AMOUNTS IN SOUTHEAST COOK NEED TO
BE ADJUSTED UPWARDS AT ALL. THE MORE RESIDUAL TIME STILL LOOKS TO
BE IN EASTERN LAKE AND PORTER COUNTIES.
MTF
&&
.PREV DISCUSSION...
SHORT TERM (TODAY THROUGH SATURDAY)...
400 AM CDT
PRIMARY SHORT TERM CONCERN IS WITH LAKE ENHANCED SYNOPTIC SNOW THIS
AFTERNOON FOLLOWED BY POTENTIAL MAJOR LAKE EFFECT EVENT OVER
NORTHWEST INDIANA TONIGHT.
SNOW IS DEVELOPING AND INCREASING IN COVERAGE AND INTENSITY OVER
CENTRAL INTO NORTHEAST WISCONSIN EARLY THIS MORNING AS SHARP UPPER
TROUGH DROPS SOUTHWARD AND LOW LEVEL FRONTOGENETIC FORCING
INCREASES. SHORT RANGE GUIDANCE GENERALLY SEEMS TO HAVE A GOOD
HANDLE ON THIS AND WOULD ANTICIPATE THIS SNOW TO CONTINUE TO DEVELOP
SOUTHWARD TOWARD THE CWA (ESPECIALLY EASTERN COUNTIES) AS THE UPPER
TROUGH CONTINUES TO DIG SOUTHWARD. AS LOW LEVEL FLOW BECOMES
NORTHERLY AND COLD AIR ADVECTION INCREASES COULD SEE SOME LAKE
ENHANCEMENT TO THIS SYNOPTIC SNOW RIGHT NEAR THE LAKE INTO SOUTHEAST
COOK COUNTY AS WELL AS INTO LAKE COUNTY INDIANA. OVERALL...NOT
EXPECTING THIS TO BE A BIG SNOW EVENT WITH GENERALLY AN INCH OR TWO
EXPECTED MOST AREAS...WITH LOCALLY 3 INCHES NOT OUT OF THE QUESTION
POSSIBLE FROM DOWNTOWN CHICAGO AND ESPECIALLY SOUTH INTO SOUTHEAST
COOK COUNTY.
EVEN THOUGH SNOWFALL TOTALS ARE GENERALLY EXPECTED TO BE GENERALLY
SUB-ADVISORY CRITERIA HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY
FOR A FEW REASONS. FIRST...SNOWFALL THIS AFTERNOON COULD HIT RATHER
SUDDENLY AND FALL MODERATELY AT TIMES WITH MOST OF THE 1 TO LOCALLY
3" ACCUMULATION OCCURRING IN SHORT PERIOD OF TIME RIGHT BEFORE
FRIDAY AFTERNOON RUSH HOUR. CONSIDERING THE POTENTIAL HIGH IMPACT OF
THE EVENT...DIDN`T THINK CANCELING THE LAKE EFFECT SNOW WATCH AND
GOING WITH NO HEADLINES WOULD BE SENDING THE CLEAREST MESSAGE TO THE
PUBLIC. ALSO...STILL NOT TOTALLY OUT OF THE QUESTION THAT HEAVIER
LAKE EFFECT SNOW COULD CLIP AREAS NEAR THE LAKE AND INDIANA STATE
LINE WITH SOME MORE INTENSE SNOW THAN IS CURRENTLY EXPECTED LATE
THIS AFTERNOON INTO EARLY THIS EVENING BEFORE A SLIGHTLY MORE
NORTHWESTERLY COMPONENT TO THE WINDS LOCK IN.
MUCH BIGGER STORY IS THE INTENSE LAKE EFFECT SNOW EVENT THAT LOOKS
TO BE SHAPING UP FOR TONIGHT OVER NORTHWEST INDIANA WHERE LAKE
EFFECT SNOW WARNINGS HAVE BEEN ISSUED. VERY COLD AIR MASS MOVING
OVER THE UNSEASONABLY MILD LAKE (OFFSHORE LAKE SFC TEMPS 4-5C) WILL
RESULT IN EXTREMELY UNSTABLE CONDITIONS DEVELOPING TONIGHT. REALLY
LOOKING LIKE A CLASSIC INTENSE SINGLE BAND SET-UP DEVELOPING BY
MID-LATE EVENING AND LINGERING INTO VERY EARLY SATURDAY MORNING.
BOUNDARY LAYER STREAMLINES SHOW FULL FETCH DOWN THE LAKE ACTUALLY
ORIGINATING FROM LAKE SUPERIOR SNOW BAND. LAKE-850MB DELTA-T PROGGED
TO INCREASE TO 20-23C OVERNIGHT WITH 700MB DELTA-T VALUES NEARING
30C AS EQUILIBRIUM LEVELS RISE TO OVER 12000FT. GIVEN THE STRONG
INSTABILITY WITH LAKE INDUCED CAPES OVER 700 J/KG AND TEMPS AT THE
EQUILIBRIUM LEVELS APPROACHING THE -30C WOULDNT BE SURPRISED TO EVEN
SEE SOME THUNDERSNOW DEVELOP AT THE HEIGHT OF THE EVENT TONIGHT.
SNOWFALL RATES WITHIN THE LAKE EFFECT SNOW BAND WILL LIKELY REACH AT
LEAST 2-3 INCHES PER HOUR WITH WHITE-OUT CONDITIONS EXPECTING TO
MAKE TRAVEL EXTREMELY DANGEROUS IF NOT OUTRIGHT IMPOSSIBLE.
GAVE VERY SERIOUS CONSIDERATION TO GOING WITH A BLIZZARD WARNING
RATHER THAN LAKE EFFECT SNOW WARNING...BUT GFS HAS WINDS COMING DOWN
QUICKER THAN THE WRF-NAM AND EVEN IF WRF-NAM VERIFIES NOT SURE THE
STRICT 3 HOUR CRITERIA WILL BE MET. REGARDLESS...OF WHETHER STRICT
CRITERIA IS OFFICIALLY MET...BLIZZARD CONDITIONS WILL LIKELY BE
EXPERIENCED WITHIN THE INTENSE SNOW BAND LATE TONIGHT. AS IS ALWAYS
THE CASE...SNOWFALL TOTALS ARE VERY DIFFICULT TO PIN DOWN IN LAKE
EFFECT SITUATIONS. IF THE BAND OF +SN SITS IN ANY ONE LOCATION FOR
AN EXTENDED PERIOD OF TIME THEN WOULDN`T TAKE MUCH IMAGINATION TO
ENVISION SNOWFALL TOTALS OF AT LEAST 18 INCHES. MODELS SUGGEST THE
BAND WILL PROBABLY BE MOBILE ENOUGH TO GENERALLY KEEP TOTALS IN THE
6-12 INCH RANGE...BUT OBVIOUSLY FORECAST CONFIDENCE ISNT
PARTICULARLY HIGH. EXPECT THE BAND WILL MAKE IT FAR ENOUGH INLAND TO
POSE A THREAT FOR SIGNIFICANT SNOWS INTO JASPER AND POSSIBLY EVEN NE
NEWTON COUNTY. HAVE ISSUED A LAKE EFFECT SNOW ADVISORY THERE
THINKING THAT THE INTENSITY WILL BE SOMEWHAT LESSENED THAT FAR
INLAND.
LAKE EFFECT BAND SHOULD SHIFT EAST OF OUR CWA EARLY SAT MORNING WITH
QUIET WEATHER EXPECTED TO FOLLOW.
IZZI
LONG TERM (SUNDAY THROUGH THURSDAY)...
322 AM CDT
STRONG HIGH PRESSURE WILL BE SPRAWLED ACROSS THE CENTRAL AND
NORTHERN PLAINS SUNDAY AS THE UPPER TROUGH AXIS SWINGS EASTWARD OFF
THE EAST COAST. MID LEVEL AIR WILL HAVE WARMED WITH THE DEPARTURE OF
THE TROUGH WITH H85 TEMPS AROUND -8C. THE HIGH WILL BE SETTLING
SOUTHEASTWARD LEAVING THE LOCAL AREA IN THE WESTERLY GRADIENT ON ITS
NORTHEASTERN FLANK SO IT WILL REMAIN A BIT BREEZY. HOWEVER...HIGH
TEMPS WILL BE A BIT WARMER THAN SATURDAY WITH READINGS IN THE UPPER
20S TO AROUND 30 WITH A FAIR AMOUNT OF SUNSHINE EXPECTED.
THE HIGH WILL BE MOVING EASTWARD ACROSS THE SOUTHEASTERN
U.S./TENNESSEE VALLEY MONDAY WITH LOW AMPLITUDE UPPER RIDGING
CROSSING THE MID AND UPPER MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. AN UPPER LEVEL TROUGH WILL MOVE FROM THE DESERT
SOUTHWEST INTO THE HIGH PLAINS MONDAY MORNING WHILE PHASING WITH A
NORTHERN STREAM OF FLOW RESULTING IN A LONGER WAVE TROUGH. THERE IS
NOT MUCH MORE THAN A WEAK BROAD SURFACE TROUGH THAT DEVELOPS IN
CONJUNCTION WITH THE UPPER FEATURE. HOWEVER...SOUTHERLY RETURN FLOW
BEHIND THE DEPARTING SURFACE HIGH WILL INTENSIFY INTO EARLY MONDAY
AFTERNOON AS MID LEVEL WARM ADVECTION COMMENCES AHEAD OF THE UPPER
TROUGH. THIS IS EXPECTED TO SPREAD LIGHT SNOW ACROSS THE AREA BY
MONDAY AFTERNOON. THE TROUGH WILL BE SOMEWHAT SLOW TO PASS GIVEN
THAT IT WILL BE RATHER BROAD SO LIGHT SNOW WILL PROBABLY CONTINUE
INTO TUESDAY MORNING. AMOUNTS DO NOT LOOK SIGNIFICANT AT THIS TIME
BUT SOME LIGHT ACCUMULATION SEEMS PLAUSIBLE...ESPECIALLY MONDAY
AFTERNOON INTO EARLY TUESDAY NIGHT.
HEIGHTS RISE MODESTLY BEHIND THE TROUGH TUESDAY INTO WEDNESDAY
LEADING TO A GRADUAL MODERATION OF TEMPS INTO THURSDAY. MODEL
AGREEMENT WITH THE UPPER FLOW DIMINISHES WITH THE HANDLING OF
TROUGHING COMING INTO THE WESTERN U.S. THE GFS BRINGS IN AN INITIAL
TROUGH INTO SOUTHERN CALIFORNIA AND THE FOUR CORNERS REGION FOLLOWED
BY A SECOND AND MORE SUBSTANTIAL TROUGH INTO WEDNESDAY. THE ECMWF IS
MORE FOCUSED ON A SINGLE TROUGH DIGGING MORE INTO THE NORTHERN BAJA
OF CALIFORNIA AND CUTTING OFF FROM THE MAIN FLOW AND MEANDERING
EASTWARD. THE GFS REMAINS MORE PROGRESSIVE WITH THE FLOW BRINGING
THE TROUGH ACROSS THE AREA TUESDAY LEADING TO ANOTHER ROUND OF
PRECIPITATION. WARMER AIR WILL BE IN PLACE ALOFT WITH H85 TEMPS A
FEW DEGREES EITHER SIDE OF 0C SO MIXED PRECIP MAY BE A CONCERN. DO
NOT HAVE A GREAT DEAL OF CONFIDENCE GIVEN THE MODEL DISCREPANCIES SO
WILL STICK WITH SLIGHT AND LOW CHANCE POPS FOR THURSDAY FOR NOW.
MDB
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* CIGS REDUCING FROM MVFR NEAR IFR CONDS THIS AFTN.
* WEST WINDS VEERING NORTH THIS AFTERNOON.
* OCCASIONAL WIND GUSTS UP TO 30 KT.
* PSBL PERIODS OF IFR VSBYS WITH THE BURSTS OF SNOW.
BEACHLER
//DISCUSSION...UPDATED 12Z...
A LOW PRESSURE SYSTEM PASSES TO THE NORTH TODAY...BUT ITS COLD
FRONT WILL PASS THROUGH THE REGION LATE THIS MORNING THROUGH EARLY
THIS AFTERNOON. LIGHT SNOW SHOWERS WILL SPREAD ACROSS THE REGION
AND WINDS WILL TURN NORTHERLY BEHIND THE FRONT. EXPECTING MVFR
VSBY IN THE LIGHT SNOW SHOWERS. MODELS INDICATE THERE WILL BE
LAKE ENDUCED LIFT AFFECTING REACHING AS FAR INWARD AS ORD AND MDW.
THE ENHANCED LIFT LOOKS LIKE IT WILL BE BELOW THE IDEAL SNOW
GROWTH ZONE...WHICH WILL RESULT IN VERY FINE SNOW FLAKES. WHILE
NOT EXPECTING MORE THAN 1 TO 2 INCHES OF TOTAL SNOW ACCUMULATION
TODAY FOR MDW AND ORD...AN ABUNDANCE OF SMALL SNOW FLAKES COMBINED
WITH WIND GUSTS UP TO 30 KT WILL RESULT IN IFR TO LIFR VSBYS THIS
AFTERNOON.
WINDS WILL TURN MORE NORTHWESTERLY LATE THIS AFTERNOON...WHICH
WILL PUSH THE SNOW BAND INTO NORTHWEST INDIANA. GYY WILL BE
HARDEST HIT BY THE SNOW TODAY...WITH AT LEAST 5 TO 7 INCHES OF
SNOW POSSIBLE. MORE SNOW COULD ACCUMULATE DEPENDING ON HOW LONG
THE LAKE EFFECT SNOW BAND RESIDES OVER GYY. LUCKILY...EXPECTING
THE WORST OF THE SNOW TO OCCUR AFTER OPERATING HOURS.
CONDITIONS WILL RAPIDLY IMPROVE BEHIND THE SNOW...WITH VFR
EXPECTED BY SATURDAY MORNING AT ALL TERMINALS EXCEPT GYY. GUSTY
NORTHWEST WINDS WILL CONTINUE THROUGH TOMORROW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM-HIGH CONFIDENCE WITH TRENDS AND TIMING THIS
AFTERNOON...INCLUDING SNOW...VSBY...AND CIGS.
* MEDIUM-HIGH CONFIDENCE IN WIND FORECAST TRENDS...MEDIUM
CONFIDENCE IN WIND SHIFT TIMING.
* MEDIUM-HIGH CONFIDENCE IN CIG FORECAST.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT/SUNDAY...VFR.
MONDAY/TUESDAY...LIGHT SNOW...IFR CIGS POSSIBLE.
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN OR SNOW.
JEE
&&
.MARINE...
305 AM CST
A STRONG PUSH OF COLD AIR WILL FOLLOW A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN TODAY. WINDS WILL QUICKLY SHIFT NORTHERLY AND
INCREASE TO GALES TO 35KT. AS TEMPERATURES PLUNGE TO WELL BELOW
32F...STRONG WINDS AND HIGH WAVES WILL COMBINE WITH THE COLD AIR TO
GENERATE CONDITIONS CONDUCIVE TO FREEZING SPRAY. WEAK CONVERGENCE
IN THE WIND FIELD OVER THE LAKE WILL ALSO LEAD TO BANDS OF HEAVY
SNOW SHOWERS AS WELL...OCCASIONALLY LIMITING VISIBILITY TO A QUARTER
MILE OR LESS AT TIMES. NORTH GALES AND FREEZING SPRAY ARE EXPECTED
TO PERSIST OVER MUCH OF THE LAKE THROUGH TONIGHT AND INTO SATURDAY
MORNING. THE NEARSHORE WATERS WILL NOT FARE MUCH BETTER...EXCEPT
THAT THE ILLINOIS NEARSHORE WATERS MAY BE SPARED THE SUSTAINED GALE
FORCE WINDS...BUT OCCASIONAL GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION. AS HIGH PRESSURE BUILDS OUT OF CANADA AND THROUGH THE
PLAINS AND MISSISSIPPI VALLEY...BRISK NORTHWESTERLY WINDS WILL
PREVAIL OVER THE LAKE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ014-ILZ022 UNTIL 9 PM FRIDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ013 UNTIL 6 PM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ001...3 PM FRIDAY TO 4 AM SATURDAY.
LAKE EFFECT SNOW WARNING...INZ002...3 PM FRIDAY TO 9 AM SATURDAY.
LAKE EFFECT SNOW ADVISORY...INZ011...6 PM FRIDAY TO 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...1 PM
FRIDAY TO 9 AM SATURDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
AM SATURDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 5 PM SATURDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...3 PM FRIDAY TO NOON
SATURDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...NOON SATURDAY TO 2
PM SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
224 PM EST FRI FEB 10 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
AN UPPER TROUGH MOVING EAST ACROSS THE CENTRAL AND SOUTHERN
MISSISSIPPI VALLEY WILL SPREAD LIGHT PRECIP INTO OUR REGION BY
AFTERNOON AS AN ARCTIC COLD FRONT OVER THE UPPER MIDWEST MOVES
ACROSS OUR REGION LATE TODAY AND EARLY TONIGHT. ON SATURDAY A COLD
FLOW OF ARCTIC AIR WILL BE ACROSS OUR REGION. SOME LAKE EFFECT
FLURRIES POSSIBLE MAINLY NORTH AND EAST. HIGH PRESSURE OVER THE
NORTHERN THIS WEEKEND WILL MOVE ACROSS OUR REGION LATE SUNDAY AND
EARLY MONDAY. THE COMBINATION OF WARM ADVECTION AND AN UPPER LEVEL
DISTURBANCE WILL BRING PRECIP ACROSS OUR REGION BY LATE MONDAY INTO
TUESDAY.
FARTHER INTO THE EXTENDED...SOME MODELS INDICATE ANOTHER WEAK
DISTURBANCE MAY AFFECT US BY THURSDAY.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE ADJUSTMENTS TO THE FORECAST BASED ON RUC WETBULB
TEMPERATURE PROGS. APPEARS 35F IS A GOOD LINE FOR WHERE SNOW
TRANSITIONS TO RAIN...SO BASED ON THIS HAVE ADJUSTED GRIDS TO
DEPICT LIKELY RAIN OR SNOW SOUTHWEST...LIKELY SNOW-SLIGHT CHANCE
TO CHANCE OF RAIN NORTHEAST OF THERE...AND THEN ALL SNOW ACROSS
THE NORTHEASTERN HALF OF THE FORECAST AREA...ROUGHLY FROM A LAF-
IND-BAK LINE NORTHEAST.
AMOUNTS REMAIN ROUGHLY THE SAME...FROM HALF INCH OR SO IN THE
SOUTHWEST...TO 1 TO AS HIGH AS 2 CENTRAL AND NORTHEAST...WITH
HIGHEST AMOUNTS NEAR MUNCIE.
DROPPED TEMPS SLIGHTLY ALSO BASED ON WETBULB TEMPS AND HOURLY
NUMERICAL GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT WILL BE MOVING THROUGH THIS EVENING AND MODELS HAVE
TRENDED A LITTLE SLOWER IN ENDING PRECIP. MOST OF THIS WILL OCCUR
BETWEEN 00Z AND 06Z AND SHOULD BE PRIMARILY ALL SNOW. WITH
TEMPERATURES DROPPING WELL BELOW FREEZING AND WINDS
INCREASING...THERE SHOULD BE SOME ISSUES WITH SLIPPERY ROADS
TONIGHT. WILL CONTINUE SPECIAL WEATHER STATEMENT ON THIS. TOTAL
SNOW AMOUNTS BY MIDNIGHT TONIGHT WILL RANGE FROM ABOUT A HALF INCH
OVER WEST AND SOUTHWEST SECTIONS TO ABOUT AN INCH AND A HALF IN OUR
EAST.
ON SATURDAY...THERE MAY BE SOME LAKE ENHANCEMENT...BUT MOST OF THIS
WILL BE LITTLE MORE THAN FLURRIES ACROSS OUR REGION AND AREA WILL
SHIFT SLOWLY EAST DURING THE DAY AS FLOW BECOMES MORE WESTERLY.
FINALLY MOSTLY CLEAR WEATHER WILL BE THE RULE SATURDAY
NIGHT...SUNDAY AND MOST OF SUNDAY NIGHT. BUT WITH SOME CLOUDS
SPREADING IN TOWARDS DAYBREAK MONDAY. WENT CLOSE TO A MAV/MET
BLEND ON TEMPERATURES MOST PERIODS. BUT THEY MAY BE TAD WARMER
ACROSS OUR NORTHWEST LATE TONIGHT WHERE SOME LAKE EFFECT CLOUDS ARE
LIKELY TO OCCUR.
WINDS GUSTS OF 25 TO 30 MPH ARE POSSIBLE TONIGHT AND SATURDAY AS
PRESSURE GRADIENT SHARPENS ACROSS OUR REGION.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
EXTENDED PERIOD BEGINS WITH A GOOD CHANCE FOR SNOW MONDAY NIGHT
THROUGH EARLY TUESDAY AS ENSEMBLES ALL SHOW UPPER FORCING
ARRIVING BY MONDAY AFTN...AHEAD OF UPPER WAVE. THIS SYSTEM SHOULD
MOVE THROUGH THE AREA MONDAY NIGHT...AND WITH GOOD AGREEMENT FROM
THESE MODELS ON POSITION OF THE FORCING/TIMING HAVE LEFT LIKELY POPS
IN DURING THIS PERIOD. RIGHT NOW IN TERMS OF SNOW AMOUNTS CENTRAL
INDIANA IS NOT LOOKING HIGH AMOUNTS...BUT 1 TO 1.5" IS POSSIBLE ATTM
BASED ON THE MOISTURE FIELDS. PRECIPITATION SHOULD MOVE AWAY FROM
THE AREA LATE TUESDAY HOWEVER MAY HANG ON LONG ENOUGH FOR US TO SEE
SOME -RA MIX WITH -SN LATER DURING THE DAY AS THOSE SURFACE TEMPS
WARM UP.
FORECAST REMAINS DRY UNTIL WED NIGHT WHEN A SOUTHERN STREAM SYSTEM
IS PROGGED TO IMPACT OUR FORECAST AREA...POSSIBLY BRINGING A CHANCE
OF RAIN AND SNOW...THROUGH NOTHING SIGNIFICANT IS EXPECTED AS
MOISTURE AMOUNTS APPEAR QUITE LIMITED. REST OF THE FORECAST PERIOD
REMAINS VERY UNSETTLED AND UNCERTAIN (AS FAR AS THE MODELS GO) WITH
ONE WEAK SYSTEM AFTER ANOTHER PASSING ACROSS THE REGION BRINGING LOW
CHANCES FOR POPS TO THE CWA.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAFS/...
A COLD FRONT FROM THE NORTHWEST WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING....CAUSING ADVERSE (IFR AND POSSIBLY SOME
LIFR) FLYING CONDITIONS AT THE TERMINALS. THIS FRONT WILL DROP
SOUTHEAST OF THE AREA AFTER 06Z.
CONDITIONS HAD BEGUN TO RAPIDLY DETERIORATE ACROSS ALL OF CENTRAL
INDIANA LATE THIS MORNNING. ADJUSTMENTS WERE MADE TO THE TAFS
BASED ON THIS...PUTTING MOST OF THE TERMINALS IN EITHER PREVAILING
OR TEMPO/D IFR. ALSO...BASED ON LATEST OBS AND TRENDS UPSTREAM,
HAVE DOUBTS AS TO WHETHER LAF/IND AND EVEN HUF WILL SEE ANY RAIN
MIX IN SO THIS WAS OMITTED FROM THEIR TAFS (ONLY GOING WITH -SN
ATTM)...WITH HUF POSSIBLY TO FOLLOW. WINDS WILL INCREASE AND SWING
TO THE SOUTHWEST BEFORE FROPA AND AFTER FRONTAL PASSAGE WILL
INCREASE TO AROUND 15 KTS SUSTAINED WITH GUSTS OF 20-30 KTS OUT OF
THE NORTHWEST...AND THIS SHOULD OCCUR ABOUT 22-23Z AT KLAF AND
MOVE TO THE SOUTHEAST FINALLY PASSING THROUGH KBMG AROUND 1Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...NIELD
SHORT TERM...JH
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1213 PM EST FRI FEB 10 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
AN UPPER TROUGH MOVING EAST ACROSS THE CENTRAL AND SOUTHERN
MISSISSIPPI VALLEY WILL SPREAD LIGHT PRECIP INTO OUR REGION BY
AFTERNOON AS AN ARCTIC COLD FRONT OVER THE UPPER MIDWEST MOVES
ACROSS OUR REGION LATE TODAY AND EARLY TONIGHT. ON SATURDAY A COLD
FLOW OF ARCTIC AIR WILL BE ACROSS OUR REGION. SOME LAKE EFFECT
FLURRIES POSSIBLE MAINLY NORTH AND EAST. HIGH PRESSURE OVER THE
NORTHERN THIS WEEKEND WILL MOVE ACROSS OUR REGION LATE SUNDAY AND
EARLY MONDAY. THE COMBINATION OF WARM ADVECTION AND AN UPPER LEVEL
DISTURBANCE WILL BRING PRECIP ACROSS OUR REGION BY LATE MONDAY INTO
TUESDAY.
FARTHER INTO THE EXTENDED...SOME MODELS INDICATE ANOTHER WEAK
DISTURBANCE MAY AFFECT US BY THURSDAY.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE ADJUSTMENTS TO THE FORECAST BASED ON RUC WETBULB
TEMPERATURE PROGS. APPEARS 35F IS A GOOD LINE FOR WHERE SNOW
TRANSITIONS TO RAIN...SO BASED ON THIS HAVE ADJUSTED GRIDS TO
DEPICT LIKELY RAIN OR SNOW SOUTHWEST...LIKELY SNOW-SLIGHT CHANCE
TO CHANCE OF RAIN NORTHEAST OF THERE...AND THEN ALL SNOW ACROSS
THE NORTHEASTERN HALF OF THE FORECAST AREA...ROUGHLY FROM A LAF-
IND-BAK LINE NORTHEAST.
AMOUNTS REMAIN ROUGHLY THE SAME...FROM HALF INCH OR SO IN THE
SOUTHWEST...TO 1 TO AS HIGH AS 2 CENTRAL AND NORTHEAST...WITH
HIGHEST AMOUNTS NEAR MUNCIE.
DROPPED TEMPS SLIGHTLY ALSO BASED ON WETBULB TEMPS AND HOURLY
NUMERICAL GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT WILL BE MOVING THROUGH THIS EVENING AND MODELS HAVE
TRENDED A LITTLE SLOWER IN ENDING PRECIP. MOST OF THIS WILL OCCUR
BETWEEN 00Z AND 06Z AND SHOULD BE PRIMARILY ALL SNOW. WITH
TEMPERATURES DROPPING WELL BELOW FREEZING AND WINDS
INCREASING...THERE SHOULD BE SOME ISSUES WITH SLIPPERY ROADS
TONIGHT. WILL CONTINUE SPECIAL WEATHER STATEMENT ON THIS. TOTAL
SNOW AMOUNTS BY MIDNIGHT TONIGHT WILL RANGE FROM ABOUT A HALF INCH
OVER WEST AND SOUTHWEST SECTIONS TO ABOUT AN INCH AND A HALF IN OUR
EAST.
ON SATURDAY...THERE MAY BE SOME LAKE ENHANCEMENT...BUT MOST OF THIS
WILL BE LITTLE MORE THAN FLURRIES ACROSS OUR REGION AND AREA WILL
SHIFT SLOWLY EAST DURING THE DAY AS FLOW BECOMES MORE WESTERLY.
FINALLY MOSTLY CLEAR WEATHER WILL BE THE RULE SATURDAY
NIGHT...SUNDAY AND MOST OF SUNDAY NIGHT. BUT WITH SOME CLOUDS
SPREADING IN TOWARDS DAYBREAK MONDAY. WENT CLOSE TO A MAV/MET
BLEND ON TEMPERATURES MOST PERIODS. BUT THEY MAY BE TAD WARMER
ACROSS OUR NORTHWEST LATE TONIGHT WHERE SOME LAKE EFFECT CLOUDS ARE
LIKELY TO OCCUR.
WINDS GUSTS OF 25 TO 30 MPH ARE POSSIBLE TONIGHT AND SATURDAY AS
PRESSURE GRADIENT SHARPENS ACROSS OUR REGION.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FORECAST FOCUS IN THE LONG TERM IS ON POTENTIAL FOR SNOW MONDAY
THROUGH TUESDAY. MODELS ARE IN GOOD AGREEMENT EARLY AND THEN DIVERGE
BY WEDNESDAY/THURSDAY. FOR TEMPERATURES THOUGHT THE ALLBLEND
INITIALIZATION CAPTURED THINGS WELL AND MADE NO ADJUSTMENTS. THIS
YIELDED TEMPERATURES NEAR AVERAGE AT THE BEGINNING OF THE LONG TERM
INCREASING TO ABOVE AVERAGE FOR THE MIDDLE THROUGH THE END OF THE
WEEK. FOR POPS DID MAKE SOME ADJUSTMENTS TO ALLBLEND BASED ON MODEL
AGREEMENT OR LACK THEREOF.
MONDAY HIGH PRESSURE WILL BE OVER THE AREA TO START THE DAY...BUT
ECMWF/GFS/GEM ARE SHOWING UPPER FORCING ARRIVING BY MONDAY AFTERNOON
AHEAD OF UPPER WAVE. THE MAJORITY OF THIS FORCING WILL MOVE THROUGH
THE AREA MONDAY NIGHT...AND WITH GOOD AGREEMENT FROM THESE MODELS ON
POSITION OF FORCING AND TIMING AS WELL AS AGREEMENT FROM NEIGHBORING
OFFICES HAVE INCREASED POPS FROM CHANCE TO LOW END LIKELY.
PRECIPITATION SHOULD MOVE OUT FROM WEST TO EAST ON TUESDAY BUT MAY
NOT BE FAST ENOUGH TO BE OUT BY THE AFTERNOON SO MAINTAINED SLIGHT
CHANCE IN THE WEST TO VERY LOW CHANCE POPS IN THE EAST. FOR
PRECIPITATION TYPE SNOW WILL BE THE RULE FROM MONDAY AFTERNOON
THROUGH MONDAY NIGHT. TUESDAY MORNING COULD SEE SOME RAIN MIX IN AND
BY TUESDAY AFTERNOON THE SOUTH COULD SEE LIGHT RAIN IF PRECIPITATION
HASN/T CLEARED OUT. UPPER RIDGING SHOULD BE IN PLACE FOR TUESDAY
NIGHT AND WEDNESDAY SO WENT DRY THEN.
LOW PRECIPITATION CHANCES MOVE BACK IN WEDNESDAY NIGHT WITH THE
POSSIBILITY OF A SURFACE FRONT FORMING JUST SOUTH OF THE AREA.
HOWEVER THIS IS ONLY THE GFS SOLUTION AND THE ECMWF MAINTAINS HIGH
PRESSURE ACROSS THE AREA. FOR WEDNESDAY NIGHT WAS FINE WITH ALLBLEND
POPS OF SLIGHT TO LOW END CHANCE. FOR THURSDAY DECREASED POPS TO LOW
END CHANCE WITH QUITE A BIT OF ENSEMBLE VARIABILITY ON PATTERN AND
GFS/ECMWF SHOWING COMPLETELY DIFFERENT SOLUTIONS /GFS FASTER AND
WETTER WITH UPPER PATTERN/.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAFS/...
A COLD FRONT FROM THE NORTHWEST WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING....CAUSING ADVERSE (IFR AND POSSIBLY SOME
LIFR) FLYING CONDITIONS AT THE TERMINALS. THIS FRONT WILL DROP
SOUTHEAST OF THE AREA AFTER 06Z.
CONDITIONS HAD BEGUN TO RAPIDLY DETERIORATE ACROSS ALL OF CENTRAL
INDIANA LATE THIS MORNNING. ADJUSTMENTS WERE MADE TO THE TAFS
BASED ON THIS...PUTTING MOST OF THE TERMINALS IN EITHER PREVAILING
OR TEMPO/D IFR. ALSO...BASED ON LATEST OBS AND TRENDS UPSTREAM,
HAVE DOUBTS AS TO WHETHER LAF/IND AND EVEN HUF WILL SEE ANY RAIN
MIX IN SO THIS WAS OMITTED FROM THEIR TAFS (ONLY GOING WITH -SN
ATTM)...WITH HUF POSSIBLY TO FOLLOW. WINDS WILL INCREASE AND SWING
TO THE SOUTHWEST BEFORE FROPA AND AFTER FRONTAL PASSAGE WILL
INCREASE TO AROUND 15 KTS SUSTAINED WITH GUSTS OF 20-30 KTS OUT OF
THE NORTHWEST...AND THIS SHOULD OCCUR ABOUT 22-23Z AT KLAF AND
MOVE TO THE SOUTHEAST FINALLY PASSING THROUGH KBMG AROUND 1Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...NIELD
SHORT TERM...JH
LONG TERM....CP
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1140 AM EST FRI FEB 10 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
AN UPPER TROUGH MOVING EAST ACROSS THE CENTRAL AND SOUTHERN
MISSISSIPPI VALLEY WILL SPREAD LIGHT PRECIP INTO OUR REGION BY
AFTERNOON AS AN ARCTIC COLD FRONT OVER THE UPPER MIDWEST MOVES
ACROSS OUR REGION LATE TODAY AND EARLY TONIGHT. ON SATURDAY A COLD
FLOW OF ARCTIC AIR WILL BE ACROSS OUR REGION. SOME LAKE EFFECT
FLURRIES POSSIBLE MAINLY NORTH AND EAST. HIGH PRESSURE OVER THE
NORTHERN THIS WEEKEND WILL MOVE ACROSS OUR REGION LATE SUNDAY AND
EARLY MONDAY. THE COMBINATION OF WARM ADVECTION AND AN UPPER LEVEL
DISTURBANCE WILL BRING PRECIP ACROSS OUR REGION BY LATE MONDAY INTO
TUESDAY.
FARTHER INTO THE EXTENDED...SOME MODELS INDICATE ANOTHER WEAK
DISTURBANCE MAY AFFECT US BY THURSDAY.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE ADJUSTMENTS TO THE FORECAST BASED ON RUC WETBULB
TEMPERATURE PROGS. APPEARS 35F IS A GOOD LINE FOR WHERE SNOW
TRANSITIONS TO RAIN...SO BASED ON THIS HAVE ADJUSTED GRIDS TO
DEPICT LIKELY RAIN OR SNOW SOUTHWEST...LIKELY SNOW-SLIGHT CHANCE
TO CHANCE OF RAIN NORTHEAST OF THERE...AND THEN ALL SNOW ACROSS
THE NORTHEASTERN HALF OF THE FORECAST AREA...ROUGHLY FROM A LAF-
IND-BAK LINE NORTHEAST.
AMOUNTS REMAIN ROUGHLY THE SAME...FROM HALF INCH OR SO IN THE
SOUTHWEST...TO 1 TO AS HIGH AS 2 CENTRAL AND NORTHEAST...WITH
HIGHEST AMOUNTS NEAR MUNCIE.
DROPPED TEMPS SLIGHTLY ALSO BASED ON WETBULB TEMPS AND HOURLY
NUMERICAL GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT WILL BE MOVING THROUGH THIS EVENING AND MODELS HAVE
TRENDED A LITTLE SLOWER IN ENDING PRECIP. MOST OF THIS WILL OCCUR
BETWEEN 00Z AND 06Z AND SHOULD BE PRIMARILY ALL SNOW. WITH
TEMPERATURES DROPPING WELL BELOW FREEZING AND WINDS
INCREASING...THERE SHOULD BE SOME ISSUES WITH SLIPPERY ROADS
TONIGHT. WILL CONTINUE SPECIAL WEATHER STATEMENT ON THIS. TOTAL
SNOW AMOUNTS BY MIDNIGHT TONIGHT WILL RANGE FROM ABOUT A HALF INCH
OVER WEST AND SOUTHWEST SECTIONS TO ABOUT AN INCH AND A HALF IN OUR
EAST.
ON SATURDAY...THERE MAY BE SOME LAKE ENHANCEMENT...BUT MOST OF THIS
WILL BE LITTLE MORE THAN FLURRIES ACROSS OUR REGION AND AREA WILL
SHIFT SLOWLY EAST DURING THE DAY AS FLOW BECOMES MORE WESTERLY.
FINALLY MOSTLY CLEAR WEATHER WILL BE THE RULE SATURDAY
NIGHT...SUNDAY AND MOST OF SUNDAY NIGHT. BUT WITH SOME CLOUDS
SPREADING IN TOWARDS DAYBREAK MONDAY. WENT CLOSE TO A MAV/MET
BLEND ON TEMPERATURES MOST PERIODS. BUT THEY MAY BE TAD WARMER
ACROSS OUR NORTHWEST LATE TONIGHT WHERE SOME LAKE EFFECT CLOUDS ARE
LIKELY TO OCCUR.
WINDS GUSTS OF 25 TO 30 MPH ARE POSSIBLE TONIGHT AND SATURDAY AS
PRESSURE GRADIENT SHARPENS ACROSS OUR REGION.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FORECAST FOCUS IN THE LONG TERM IS ON POTENTIAL FOR SNOW MONDAY
THROUGH TUESDAY. MODELS ARE IN GOOD AGREEMENT EARLY AND THEN DIVERGE
BY WEDNESDAY/THURSDAY. FOR TEMPERATURES THOUGHT THE ALLBLEND
INITIALIZATION CAPTURED THINGS WELL AND MADE NO ADJUSTMENTS. THIS
YIELDED TEMPERATURES NEAR AVERAGE AT THE BEGINNING OF THE LONG TERM
INCREASING TO ABOVE AVERAGE FOR THE MIDDLE THROUGH THE END OF THE
WEEK. FOR POPS DID MAKE SOME ADJUSTMENTS TO ALLBLEND BASED ON MODEL
AGREEMENT OR LACK THEREOF.
MONDAY HIGH PRESSURE WILL BE OVER THE AREA TO START THE DAY...BUT
ECMWF/GFS/GEM ARE SHOWING UPPER FORCING ARRIVING BY MONDAY AFTERNOON
AHEAD OF UPPER WAVE. THE MAJORITY OF THIS FORCING WILL MOVE THROUGH
THE AREA MONDAY NIGHT...AND WITH GOOD AGREEMENT FROM THESE MODELS ON
POSITION OF FORCING AND TIMING AS WELL AS AGREEMENT FROM NEIGHBORING
OFFICES HAVE INCREASED POPS FROM CHANCE TO LOW END LIKELY.
PRECIPITATION SHOULD MOVE OUT FROM WEST TO EAST ON TUESDAY BUT MAY
NOT BE FAST ENOUGH TO BE OUT BY THE AFTERNOON SO MAINTAINED SLIGHT
CHANCE IN THE WEST TO VERY LOW CHANCE POPS IN THE EAST. FOR
PRECIPITATION TYPE SNOW WILL BE THE RULE FROM MONDAY AFTERNOON
THROUGH MONDAY NIGHT. TUESDAY MORNING COULD SEE SOME RAIN MIX IN AND
BY TUESDAY AFTERNOON THE SOUTH COULD SEE LIGHT RAIN IF PRECIPITATION
HASN/T CLEARED OUT. UPPER RIDGING SHOULD BE IN PLACE FOR TUESDAY
NIGHT AND WEDNESDAY SO WENT DRY THEN.
LOW PRECIPITATION CHANCES MOVE BACK IN WEDNESDAY NIGHT WITH THE
POSSIBILITY OF A SURFACE FRONT FORMING JUST SOUTH OF THE AREA.
HOWEVER THIS IS ONLY THE GFS SOLUTION AND THE ECMWF MAINTAINS HIGH
PRESSURE ACROSS THE AREA. FOR WEDNESDAY NIGHT WAS FINE WITH ALLBLEND
POPS OF SLIGHT TO LOW END CHANCE. FOR THURSDAY DECREASED POPS TO LOW
END CHANCE WITH QUITE A BIT OF ENSEMBLE VARIABILITY ON PATTERN AND
GFS/ECMWF SHOWING COMPLETELY DIFFERENT SOLUTIONS /GFS FASTER AND
WETTER WITH UPPER PATTERN/.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAFS/...
1600Z UPDATE...CONDITIONS HAVE IN THE LAST HOUR BEGUN TO RAPIDLY
DETERIORATE ACROSS ALL OF CENTRAL INDIANA. HAVE MADE ADJUSTMENTS
TO TAFS BASED ON THIS...PUTTING MOST OF THE TERMINALS IN EITHER
PREVAILING OR TEMPO/D IFR. ALSO BASED ON LATEST OBS AND TRENDS
UPSTREAM, HAVE DOUBTS AS TO WHETHER LAF AND IND WILL SEE ANY RAIN
MIX IN SO THIS WAS OMITTED FROM THEIR TAFS...WITH HUF POSSIBLY TO
FOLLOW. PREVIOUS DISCS FOLLOW....
1430Z UPDATE...AVIATION FORECAST APPEARS TO BE IN GOOD SHAPE BASED
ON LATEST TRENDS. DID NOT NEED TO MAKE MANY ADJUSTMENTS TO THE
TAFS ATTM. PREVIOUS DISC FOLLOWS...
A LOW PRESSURE SYSTEM FROM THE SOUTH AND A COLD FRONT FROM THE
NORTHWEST WILL BOTH MOVE ACROSS THE AREA TODAY AND CREATE ADVERSE
FLYING CONDITIONS AT THE SITES. STARTING OUT WITH VFR CEILINGS WILL
DETERIORATE TO MVFR BY MIDDAY AND FINALLY IFR FOR AWHILE THIS
EVENING. WINDS WILL INCREASE AND SWING TO THE SOUTHWEST BEFORE
FRONTAL PASSAGE AND AFTER FRONTAL PASSAGE WILL INCREASE TO AROUND 15
KTS SUSTAINED WITH GUSTS OF 20-30 KTS OUT OF THE NORTHWEST...AND
THIS SHOULD OCCUR ABOUT 22-23Z AT KLAF AND MOVE TO THE SOUTHEAST
FINALLY PASSING THROUGH KBMG AROUND 1Z. LIGHT SNOW WILL BE POSSIBLE
BY LATE MORNING...CHANGING TO A RAIN/SNOW MIX THIS AFTERNOON AND
FINALLY CHANGING OVER TO SNOW THIS EVENING AROUND FRONTAL PASSAGE.
WITH THE HIGHER WINDS THIS COULD BRING HEAVIER SNOW AND COULD SEE
IFR VISIBILITIES WITH THE LAST FEW HOURS OF THE SNOW AS WELL. SNOW
SHOULD COME TO AN END BY 6Z OR SO AND CLOUD COVER SHOULD IMPROVE TO
MVFR BUT WIND GUSTS WILL CONTINUE THROUGH THE NIGHT/MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...NIELD
SHORT TERM...JH
LONG TERM....CP
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 PM CST FRI FEB 10 2012
.SYNOPSIS...
12Z UA ANALYSIS HAS A COLD FRONT FROM THE MACKINAC STRAITS INTO
NORTHERN KANSAS WITH TROFS FROM THE MID ATLANTIC BACK INTO THE
PLAINS. SATELLITE AND RADAR TRENDS THROUGH MID AFTERNOON SHOWS AREAS
OF LIGHT SNOW AND SNOW SHOWERS ACROSS THE WESTERN GREAT LAKES WITH
CLEARING SKIES IN MINNESOTA.
18Z SFC ANALYSIS HAS A LOW JUST EAST OF KMKG AND ANOTHER JUST
NORTHEAST OF KORD. THE ARCTIC FRONT RAN FROM THE SECOND LOW
SOUTHWEST INTO NORTHERN TEXAS. DEW POINTS WERE IN THE 20S AND 30S
AHEAD AND IMMEDIATELY BEHIND THE FRONT WITH SINGLE DIGITS ABOVE AND
BELOW ZERO ACROSS THE NORTHERN PLAINS.
&&
.SHORT TERM...TONIGHT AND SATURDAY...
RUC TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE DOING A
REASONABLY GOOD JOB OF DEPICTING THE CURRENT CLOUD COVER ACROSS THE
AREA. SNOW SHOWERS/FLURRIES WILL CONTINUE THROUGH THE AFTERNOON WITH
MOST SNOW SHOWERS DISSIPATING WITH SUNSET. STRONG CYCLONIC FLOW AND
VORT MAXES ROTATING THROUGH THE AREA SHOULD PROLONG THE FLURRIES
INTO THE EARLY EVENING OVER ROUGHLY THE EASTERN HALF OF THE CWFA.
GENERAL ACCUMULATIONS SHOULD RANGE FROM A TRACE TO A DUSTING.
A FEW HOURS AGO THE RUC WAS INDICATING CLEARING WOULD OCCUR FROM THE
NORTHWEST AFTER MID EVENING AND THEN TAKE MOST OF THE NIGHT TO CLEAR
OUT EAST OF THE MISSISSIPPI. HOWEVER...A NEW CLEAR AREA HAS
DEVELOPED IN AN AREA OF SUBSIDENCE ACROSS NORTHERN WISCONSIN. RUC
TRENDS USING THE 900-950MB AND 0.5-1.0KM RH LAYERS ARE NOW
SUGGESTING THE CWFA MAY SEE CLEARING STARTING FROM THE NORTHWEST AND
WEST AFTER MID-EVENING AND ALSO FROM THE NORTHEAST. IF THIS DOES
OCCUR THEN ROUGHLY THE SOUTHEAST QUADRANT OF THE CWFA WOULD BE THE
LAST TO CLEAR OUT AFTER MIDNIGHT.
TEMPERATURES WILL BE INTERESTING. AREAS THAT CLEAR OUT SOONER WILL
DROP QUICKLY DUE TO THE CAA THAT WILL CONTINUE OVERNIGHT. THE FACT
THAT WINDS WILL NOT DECOUPLE FROM THE BOUNDARY LAYER WILL BE WHAT
KEEPS LOWS ABOVE ZERO. FAVORED COLD AREAS IN THE WAPSI AND SAUK
VALLEYS MAY APPROACH ZERO IN SPITE OF THE WINDS. THE WIND AND
TEMPERATURES WILL DROP WIND CHILLS WELL BELOW ZERO BUT ARE EXPECTED
TO REMAIN JUST ABOVE ADVISORY CRITERIA.
SATURDAY WILL BE A COLD BRISK DAY. ARCTIC HIGH PRESSURE BUILDING
INTO THE AREA WILL RESULT IN SUNNY SKIES BUT WIND CHILLS ARE
EXPECTED TO REMAIN BELOW ZERO FOR MUCH OF THE MORNING. MAX
TEMPERATURES WILL STRUGGLE TO GET INTO THE UPPER TEENS AND LOWER 20S
BY MID AFTERNOON.
..08..
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
A HIGH PRESSURE RIDGE CENTERED OVER WESTERN IOWA SATURDAY EVENING
WILL MOVE EAST THROUGH THE MID MISSISSIPPI RIVER VALLEY BY MONDAY
MORNING. TEMPERATURES WILL BE THE MAIN CONCERN SATURDAY NIGHT AND
SUNDAY WITH THE RIDGE AXIS JUST WEST OF THE CWFA. THERE SHOULD BE
ENOUGH OF A PRESSURE GRADIENT TO KEEP WINDS FROM DECOUPLING. THE
WIND ALONG ALONG WITH BARE GROUND SHOULD KEEP MIN TEMPS SATURDAY
NIGHT ABOVE ZERO. ALTHOUGH A SMALL PART OF THE SOUTHWEST CWFA COULD
SLIP BELOW ZERO SINCE VISIBLE SATELLITE IMAGERY SHOWS SOME SNOW
COVER NOSING INTO THE AREA. TEMPS ARE EXPECTED TO REBOUND INTO THE
20S FOR SUNDAY.
PRECIPITATION CHANCES ENTER THE PICTURE SUNDAY NIGHT THROUGH TUESDAY
AS RETURN FLOW SETS UP BEHIND THE RETREATING LOW LEVEL RIDGE AND A
SHORT WAVE MOVES FROM THE NORTHERN PLAINS THROUGH THE MID AND UPPER
MISSISSIPPI VALLEY. THE GFS/NAM ARE THE MOST BULLISH ON PRECIP
DURING THIS PERIOD...GENERATING ABOUT 2 TO 3 TENTHS OF INCH WATER
EQUIVALENT WHILE THE ECMWF PRODUCES 1 TO 2 TENTHS. TEMPERATURES
WILL BE COLD ENOUGH THROUGH THE EVENT FOR ALL SNOW. KEPT AMOUNTS
IN THE 1 TO 3 INCH RANGE WITH THE HIGHEST AMOUNTS WEST AND NORTH.
IF THE GFS VERIFIES THEN THE 3 INCH AMOUNTS SHOULD BE REALIZED WHILE
THE ECMWF WOULD SUPPORT AMOUNTS CLOSER TO AN INCH. THE MEASURABLE
SNOW SHOULD END MONDAY EVENING WITH SOME FLURRIES LINGERING INTO
TUESDAY...SPECIALLY EAST OF THE MISSISSIPPI RIVER.
MODELS CONTINUE TO SHOW A SPLIT FLOW REGIME THROUGH THE REST OF THE
FORECAST PERIOD WITH TEMPERATURES RETURNING TO NEAR OR JUST ABOVE
NORMAL. MOST OF THE SOLUTIONS MOVE A NORTHERN STREAM TROF THROUGH
THE REGION THURSDAY OR FRIDAY BUT KEEP THE SYSTEM UN-PHASED AND
MOISTURE STARVED. THE LONE EXCEPTION IS THE 12Z ECMWF WHICH PHASES
THE TROF WITH THE SOUTHERN STREAM...RESULTING IN A MODERATE PRECIP
EVENT FOR THE REGION. AT THIS POINT THERE IS LOW CONFIDENCE IN THE
EXTENDED PROGS SO KEPT SOME SLIGHT CHANCE POPS IN FOR ALL OR PART OF
THE AREA WEDNESDAY THROUGH FRIDAY. ..DLF..
&&
.AVIATION...
DAYTIME HEATING IS ALLOWING CIGS TO RISE BUT MVFR CONDITIONS REMAIN
COMMON WITH POCKETS OF VFR. CONDITIONS TO SLOWLY IMPROVE TO VFR CIGS
AFT 00Z/11 WITH CLR SKIES DVLPG 06Z-12Z/11. CONVECTIVE SHSN AND -SN
WILL TAPER TO FLURRIES BY 00Z/11 AND END BY 03Z/11. WINDS WILL
SLOWLY DECREASE AFT SUNSET BUT ARE EXPECTED TO REMAIN ABV 12 KTS.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1056 AM CST FRI FEB 10 2012
.UPDATE...
SATELLITE TRENDS SHOW CLOUDS DEVELOPING BACK TO THE SOUTHWEST
ACROSS EASTERN MINNESOTA WITH FLURRIES AND SNOW SHOWERS BECOMING
MORE WIDESPREAD ON AREA RADARS.
RUC TRENDS AND THE 12Z WRF RUN SHOW THE MODELS HAVE SOME IDEA
ABOUT THE CLOUDS USING THE 900-950MB RH LAYER AND 0.5-1.0KM RH
LAYER. SATELLITE TRENDS ALONG WITH INPUTS FROM THE RUC/WRF
INDICATE CLOUDS WILL REMAIN ACROSS THE AREA TODAY AND INTO THE
EVENING. CONCEPTUALLY...THIS MAKES SENSE SINCE THERE IS STRONG
CYCLONIC FLOW ALOFT WITH TWO MORE VORT MAXES THAT WILL ROTATE
THROUGH THE AREA. STRONG SUBSIDENCE BEHIND THE SECOND VORT MAX
SHOULD ALLOW CLEARING TO DEVELOP LATE THIS EVENING OUT WEST AND
SPREAD SOUTH/EAST AFTER MIDNIGHT. BASED ON THE RUC/WRF TRENDS
CLOUDS WILL PROBABLY LINGER IN THE FAR EAST UNTIL NEARLY SUNRISE.
BASED ON SFC REPORTS...POPS HAVE BEEN PULLED FURTHER WEST FOR LATE
THIS MORNING AND AFTERNOON.
MAX TEMPERATURES HAVE ALREADY OCCURRED AND THE CAA WILL RESULT IN
TEMPERATURES DOING A SLOW FALL FOR THE REMAINDER OF THE DAY.
AN UPDATED FCST REFLECTING THIS HAS ALREADY BEEN SENT.
..08..
&&
.AVIATION...
SATELLITE TRENDS COMBINED WITH TRENDS FROM THE RUC MODEL INDICATE
MVFR CIGS WILL CONTINUE PAST 00Z/11 FOR ALL TAF SITES. SHSN ARE
MOST LIKELY TO BE SEEN AT KDBQ/KMLI WITH FLURRIES AT KCID/KBRL.
THE SHSN MAY BRIEFLY DROP VSBYS TO MVFR OR IFR IF THEY IMPACT A
TAF SITE. VFR CONDITIONS SHOULD DVLP AT ALL TAF SITES AFT 06Z/11.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1154 PM CST THU FEB 9 2012
.AVIATION...
STRATUS WITH VFR TO MVFR CIGS WILL PERSIST THROUGH THU AM. ARCTIC
FRONT TO PASS THROUGH TERMINALS BETWEEN ROUGHLY 10Z-14Z. W/SW
WINDS AROUND 10 KTS AHEAD OF FRONT WILL SHIFT TO NW AND BECOME
GUSTY AT 15-30 KTS WITH FRONTAL PASSAGE. MAY BE BRIEF WINDOW
OF PARTIAL CLEARING PRIOR TO FROPA ESPECIALLY AT KCID... AND SOME
LIGHT FOG WITH 3-5SM VSBY POSSIBLE. OTRW... CIGS MORE WIDESPREAD
MVFR THU AM AS MUCH COLDER AIR OVERTAKES REGION. FLURRIES WILL
LIKELY BE WRUNG OUT WITH THE COLD ADVECTION WITH FEW SHSN POSSIBLE
BY MID AM THROUGH EARLY AFTN AS ATMOSPHERE BECOMES MORE UNSTABLE.
MODELS WANT TO KEEP A LOT OF LOW LEVEL MOISTURE AROUND THU NGT
BUT SATL AND OBS POST FRONTAL SHOW LOW CLOUDS NOT LASTING MORE
THAN ABOUT 4-6 HRS OR SO AFTER FROPA BEFORE SCOURING OUT WITH STRONG
SUBSIDENCE. THEREFORE.. CONTINUED TRENDS OF DECREASING LOW CLOUDS
DURING AFTN THROUGH SUNSET. WINDS TO REMAIN GUSTY 15-20+ KTS THU
NGT.
&&
.PREV DISCUSSION... /ISSUED 305 PM CST THU FEB 9 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS SEVERAL SHORTWAVE TROFS FROM THE GREAT LAKES
BACK INTO THE PLAINS. AN 850MB COLD FRONT RAN FROM CANADIAN UA SITE
CYEG IN ALBERTA PROVINCE TO THE SOUTH EDGE OF JAMES BAY. SATELLITE
TRENDS THROUGH MID AFTERNOON SHOW THE LOW CLOUDS MOVING EAST ACROSS
THE AREA WITH CLEARING ACROSS SOUTHERN MINNESOTA AND WISCONSIN. THE
LOW POST FRONTAL CLOUDS OF THE ARCTIC FRONT WERE ACROSS NORTH DAKOTA
AND NORTHERN MINNESOTA.
18Z SFC ANALYSIS HAD A RIDGE RUNNING FROM THE LOWER MISSISSIPPI
VALLEY INTO THE OHIO VALLEY. THE ARCTIC FRONT RAN FROM EASTERN
MONTANA INTO NORTHWEST MINNESOTA. DEW POINTS ACROSS THE MIDWEST WERE
GENERALLY IN THE TEENS AND 20S WITH 30S IN THE SOUTHERN PLAINS AND
EASTERN KANSAS.
SHORT TERM...TONIGHT AND FRIDAY...
THE SHALLOW NATURE OF THE CLOUDS...ROUGHLY 1-2KFT...IS ONE OF MANY
REASONS WHY THE MODELS ARE DOING AN EXTREMELY POOR JOB OF DEPICTING
THEM AND HANDLING THEIR OVERALL MOVEMENT. THESE CLOUDS PLAY
SIGNIFICANTLY INTO SENSIBLE WX TRENDS TONIGHT BEFORE THE ARCTIC
FRONT ARRIVES.
THE RUC AND WRF HAVE A VAGUE IDEA ABOUT THE CLOUDS AND EITHER THE
0.5-1KM LAYER OR 0.5KM LAYER IS AT LEAST HINTING AT THE CLOUDS.
USING THIS ALONG WITH EXTRAPOLATION FROM CURRENT SATELLITE TRENDS
RESULTS IN CLOUDY SKIES FOR THE REMAINDER OF THE AFTERNOON AND INTO
THE EVENING HOURS. BASED ON THE CURRENT CLEAR AREA TO THE NORTH AND
WHAT THE MODELS ARE SUGGESTING...THE CLOUDS SHOULD PARTIALLY BREAK
UP ACROSS THE NORTHERN THIRD OF THE CWFA LATE THIS EVENING. WHAT
PARTIAL CLEARING THAT DEVELOPS WILL BE FORCED SOUTH AFTER MIDNIGHT
AS THE ARCTIC FRONT STARTS MOVING INTO THE CWFA.
BECAUSE OF THE CLOUDS...TEMPERATURES WILL BE WARMER THAN LAST NIGHT.
ANY AREAS THAT DO SEE PARTIAL OR A TOTAL CLEARING SHOULD DROP AND
THEN REBOUND AS THE POST FRONTAL CLOUDS OF THE ARCTIC FRONT ARRIVE.
THE CAA BEHIND THE ARCTIC FRONT IS IMPRESSIVE. LOW TEMPERATURES
TONIGHT WILL LIKELY OCCUR 7-8 AM FRIDAY MORNING.
ON FRIDAY...THE ARCTIC FRONT WILL CLEAR THE CWFA BY MID TO LATE
MORNING WITH POST FRONTAL STRATUS CLOUDS FOLLOWING BEHIND IT. THE
COMBINATION OF CAA...STRONG CYCLONIC FLOW ALOFT...A STRONG VORT
MAX...STEEPENING LOW LEVEL LAPSE RATES...AND THE STRONGER FEBRUARY
SUN ALL POINT TO SNOW SHOWERS DEVELOPING FROM LATE MORNING THROUGH
THE AFTERNOON. FCST SOUNDINGS DO SHOW SOME SMALL CAPE DEVELOPING AS
LAPSE RATES STEEPEN. PRIOR TO THE SNOW SHOWERS DEVELOPING THERE ARE
REASONABLY LOW CONDENSATION PRESSURE DEFICITS WITH SOME FORCING AND
F VECTOR CONVERGENCE. THUS FLURRIES MAY BE POSSIBLE WITH THE POST
FRONTAL STRATUS BEFORE THE SNOW SHOWERS DEVELOP.
SNOW AMOUNTS WITH THE SNOW SHOWERS WILL BE VARIED. AMOUNTS COULD
RANGE FROM ONLY A TRACE TO AROUND ONE HALF INCH IN THE STRONGER
SHOWERS.
WINDS WILL BE QUITE BRISK ON FRIDAY AND MAY BE LOCALLY STRONGER
AROUND SNOW SHOWERS.
MAX TEMPERATURES FRIDAY WILL LIKELY OCCUR 9-11 AM WITH TEMPERATURES
EITHER STEADY OR SLOWLY FALLING DURING THE AFTERNOON. ..08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY...
SEASONALLY COLD...A LIGHT SNOW EVENT MONDAY WITH A MODEST WARMING
TREND INTO MIDDLE OF NEXT WEEK.
OVERALL...LARGE SCALE FEATURES REASONABLE BUT LOW LEVEL BL PROBLEMS
CONTINUE WITH MOST SOLUTIONS T/TD PROFILES LOWEST 2K AGL STILL OFF.
MAIN CONTRIBUTOR IS OUR UNSEASONABLY LOW AMOUNTS OF SNOW NOT HANDLED
BY PHYSICS PACKAGES. THIS IS RESULTING IN BL FORECASTS...ESPECIALLY
AMERICAN SOLUTIONS EITHER TOO MOIST OR TOO DRY. INITIALIZATION AND
VERIFICATION AGAIN SUGGESTS A HIGHER WEIGHT BE GIVEN TO COLDEST
GUIDANCE FOR MIN TEMPERATURES WITH ARCTIC AIR IF NOT A FEW DEGREES
COLDER. FOR HIGHS...ON THE WARM END FOR MAX TEMPS INTO MONDAY.
TEXTBOOK WIDESPREAD LIGHT SNOW EVENT MONDAY WITH LOCAL TOOLS
SUGGESTING .5 TO 1.5 INCHES OF SNOW MOST LOCATIONS AT THIS TIME. NEXT
24 HOURS...FINER DETAILS MAY SUGGEST A LEAD VORT MAX...THEN SOME
ISOLATED 2 TO 3 INCHES NOT OUT OF THE QUESTION...THIS SHOULD BE KNOWN
THIS TIME TOMORROW.
FRIDAY NIGHT...CLEARING WITH STRONG CAA WITH NW WINDS 10-20+ MPH IN
THE EVENING DECREASING TO 5-10 MPH OVERNIGHT. LOCAL TECHNIQUES
SUPPORT 0-5F ABOVE NW 1/2 AND 5-10F ABOVE SE 1/2. WHEN ADJUSTING FOR
BL PROBLEMS...POSSIBLE MINS MAY STILL BE 2-5 DEGREES TOO MILD FOR
MANY IF NOT MOST LOCATIONS FOR LATER SIFTS TO REASSESS.
SATURDAY AND SUNDAY...FAIR AND COLD WITH HIGHS UPPER TEENS TO MID 20S
BOTH DAYS AND LOWS SUNDAY AM IN THE SINGLE DIGITS WITH SOME BELOW
ZERO READINGS AGAIN POSSIBLE NW SECTIONS. SUNDAY NIGHT...INCREASING
CLOUDS LATE WITH MINS IN THE TEENS WITH SLOWLY RISING TEMPERATURES
POSSIBLE AFTER MIDNIGHT.
MONDAY... UPPED POPS TO LOW END LIKELY TO HIGH END CHANCE WITH AREAS
OF LIGHT SNOW TO OVERSPREAD AREA THROUGH MONDAY NIGHT. LOCAL TOOLS
SUGGEST MOSTLY .5-1.5 INCHES ATTM WITH RISK OF SOME ISOLATED HIGHER
AMOUNTS OF 2-3 INCHES POSSIBLE IF LEAD VORT MAX IS STRONGER. BL
ISSUES MAKE THIS A CHALLENGE THAT LATER SHIFTS WILL NEED TO STAY ON
TOP OF. HIGHS NEAR FREEZING WITH SOUTH WINDS LIMITING ACCUMULATIONS
ON THE MOST TRAVELED ROADS. MONDAY...LIGHT SNOW TO DIMINISH TO
FLURRIES OR END BY LATE OVERNIGHT HOURS. WITH MINOR ACCUMULATIONS IN
THE FAR EAST UNTIL MIDNIGHT. LOWS WITH CLEARING IN THE NW SECTIONS
MAY NEED TO BE TRIMMED FURTHER BY 2 TO 5 DEGREES.
TUESDAY THROUGH THURSDAY...DRY TO MOSTLY DRY WITH LOW CHANCE POPS ON
WEDNESDAY AND THURSDAY...MOSTLY LOWER SOUTH SECTIONS. MAIN FORCING
IS SUGGESTED TO PASS TO THE SOUTH SO ANY AMOUNTS TO BE LIGHT IF NOT
DRY. LATER SHIFTS MAY BE ABLE TO REMOVE POPS MANY LOCATIONS THE NEXT
FEW DAYS. TEMPERATURES OVERALL TO TREND NEAR TO SLIGHTLY ABOVE
NORMAL. ..NICHOLS..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 PM MST FRI FEB 10 2012
.SYNOPSIS...
ISSUED AT 222 PM MST FRI FEB 10 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE SCALE
TROUGH ACROSS SOUTHERN CANADA EXTENDING SOUTH ACROSS THE GREAT
LAKES AND NORTHERN PLAINS. AT THE SURFACE THE COLD FRONT THAT
PASSED THROUGH THE CWA THIS MORNING HAS STALLED ALONG THE W/SW
PART OF THE CWA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 222 PM MST FRI FEB 10 2012
TONIGHT THROUGH EARLY SATURDAY...A FRONTAL BOUNDARY WILL REMAIN
NEARLY STATIONARY ACROSS THE HIGHER TERRAIN OF THE CENTRAL HIGH
PLAINS. EXPECT AREAS OF LIGHT SNOW TO DEVELOP OVERNIGHT IN THE
VICINITY OF THIS BOUNDARY AS WEAK WAVES MOVE THROUGH THE NORTHWEST
FLOW ALOFT. THERE IS A SLIGHT CHANCE OF SOME FREEZING FOG IN VERY
CLOSE PROXIMITY TO THE FRONT OVERNIGHT OVER FAR EASTERN COLORADO
WHERE THE LOW CLOUDS WILL INTERSECT THE TERRAIN. HAVE TRIMMED THE
AREAS OF FREEZING FOG DOWN SOME...BUT HAVE KEPT IT IN THERE. THE
AIRMASS BEGINS DRYING OUT OVERNIGHT AS THE COLD AIR CONTINUES TO
PUSH FURTHER INTO THE REGION...SO HAVE DECREASED PRECIPITATION AND
CLOUD COVER FROM NORTHEAST TO SOUTHWEST OVERNIGHT THROUGH EARLY
SATURDAY MORNING.
LOCKHART
SATURDAY THROUGH SATURDAY NIGHT...WITH BAROCLINIC ZONE AND
LINGERING H85-H7 FRONTOGENSIS ACROSS THE WESTERN CWA...CANT RULE
OUT CONTINUED LIGHT SNOW THROUGH MID AFTERNOON SATURDAY. AIRMASS
CONTINUES TO DRY OUT THROUGH MIDDAY FROM THE NORTHEAST...SO I HAVE
KEPT CHANCE MENTION LIMITED TO FAR WESTERN CWA THROUGH 21Z. WITH
LINGERING CLOUD COVER AND VERY COLD AIRMASS IN PLACE TEMPERATURES
WILL STRUGGLE TO WARM MUCH. CURRENT FORECAST ALLOWS FOR SOME
DIURNAL WARMING WITH TEMPS IN THE MID TEENS TO LOW 20S ACROSS MUCH
OF THE CWA...AND AROUND 12 NEAR MCCOOK. CONSIDERING THE COLD
AIRMASS ALOFT AND LINGERING LOW CLOUDS...THIS MAY BE TOO
OPTIMISTIC. MODEL SOUNDINGS STILL SHOWING WARM LAYER ABOVE H85
ACROSS THE WESTERN PARTS OF THE CWA SATURDAY NIGHT...WITH SHALLOW
COLD NEAR SATURATED LAYER BELOW THIS. WITH UPSLOPE STILL
PERSISTING ALONG BAROCLINIC ZONE IN EASTERN COLORADO CANT RULE
OUT FREEZING FOG OR FREEZING DRIZZLE THROUGH EARLY SUNDAY MORNING.
I SAW NO NEED TO MAKE ANY MAJOR CHANGES TO PREVIOUS FORECAST WHICH
ALREADY HAD AREAS OF FREEZING FOG/DRIZZLE SATURDAY NIGHT THROUGH
EARLY SUNDAY MORNING.
DR
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 222 PM MST FRI FEB 10 2012
SUNDAY THROUGH MONDAY...SHORTWAVE RIDGING SHOULD KEEP CONDITIONS
DRY DURING THE DAY SUNDAY...WITH TEMPERATURES MODERATING ALOFT
FROM THE WEST. LINGERING CLOUD COVER WILL STILL LIMIT THE AMOUNT
OF DIURNAL WARMING AT THE SURFACE...SO TEMPS WILL LIKELY STILL
REMAIN BELOW FREEZING IN THE E/NE HALF OF THE CWA. A SHORTWAVE
TROUGH WILL MOVE IN THE REGION BY SUNDAY NIGHT. THIS SYSTEM DOES
NOT APPEAR TO BE VERY WELL ORGANIZED WITH MAIN H25-H3 JET OVER
OKLAHOMA PANHANDLE. THERE STILL APPEARS TO BE ENOUGH LIFT/MOISTURE
THAT I CANT RULE OUT SNOW SUNDAY NIGHT THROUGH MONDAY MORNING. BY
MONDAY AFTERNOON SHORTWAVE RIDGING BUILDS BACK OVER CWA.
TUESDAY THROUGH FRIDAY...SPLIT FLOW DOMINATES THE PATTERN
THROUGH THE REMAINING EXTENDED PERIODS. WHILE GUIDANCE IN MODERATE
AGREEMENT ON THE OVERALL PATTER...THERE IS VERY POOR RUN TO RUN
CONSISTENCY IN REGARDS TO THE HANDLING OF SMALLER SCALE FEATURES.
BEST CHANCE FOR PRECIP STILL APPEARS TO BE TUESDAY NIGHT THROUGH
WEDNESDAY NIGHT AS A SERIES OF SHORTWAVE TROUGHS MOVE THROUGH THE
PLAINS. POSITION/TIMING OF THESE FEATURES HAS BEEN ALL OVER THE
PLACE THE LAST FEW DAYS. THE 00Z ECMWF AND 00Z/12 GFS WERE
STARTING TO SHOW SIMILAR TRENDS FOR PRECIP OVER OUR CWA...WITH
LIGHT SNOW PREDOMINATELY OVER THE SOUTHERN HALF OF THE CWA QUICKLY
EXITING THE REGION BY TUESDAY AFTERNOON/WEDNESDAY NIGHT. THE 12Z
ECMWF AND GEM ARE BOTH MUCH MORE BULLISH WITH THIS SYSTEM
PRODUCING A CLOSED H5 CENTER AND MUCH MORE PRECIPITATION...WITH
THE 12Z ECMWF FURTHER NORTH AND LINGERS PRECIP THROUGH THURSDAY.
THIS IS SIGNIFICANT DEVIATION FROM PREVIOUS RUN AND ENSEMBLE DATA.
CONFIDENCE IS PRETTY LOW RIGHT NOW IN ANY PARTICULAR SOLUTION AT
THIS POINT CONSIDERING THE CHAOTIC NATURE OF THIS TYPE OF PATTER.
I KEPT THE FORECAST ON THE CONSERVATIVE END OF THE MODEL
SPREAD...WITH SLIGHT CHANCE POPS TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT. TEMPERATURES THROUGH THIS PERIOD SHOULD REMAIN SLIGHTLY
BELOW NORMAL WITH HIGHS IN THE UPPER 30S/LOW 40S.
DR
&&
.AVIATION...
1226 PM MST FRI FEB 10 2012
AREAS OF LOW CLOUDS HAVE BECOME LESS EXTENSIVE THROUGH THE
MORNING...BUT ARE EXPECTED TO RETURN OVERNIGHT ALONG WITH A
POSSIBILITY OF LIGHT SNOW IN THE VICINITY OF A COLD FRONT DRAPED
ACROSS THE CENTRAL HIGH PLAINS. CHANCES OF LIGHT SNOW AND LOWER
FLIGHT CATEGORIES WILL BE GREATER AT KGLD IN CLOSER PROXIMITY TO
THE FRONT.
VFR CONDITIONS WILL CONTINUE AT BOTH KGLD AND KMCK THROUGH 00Z.
AFTER 00Z...EXPECT LOW CLOUDS AND LOWER VISIBILITIES TO BECOME
MORE EXTENSIVE AS AREAS OF LIGHT SNOW DEVELOP AND PERSIST THROUGH
ABOUT 06Z IN THE VICINITY OF THE FRONTAL BOUNDARY THAT HAS STALLED
OVER EASTERN COLORADO. KMCK WILL SEE MVFR CONDITIONS WHILE KGLD
WILL BE MVFR WITH OCCASIONAL IFR WITH LIGHT SNOW THROUGH ABOUT
12Z. KMCK WILL IMPROVE TO VFR CONDITIONS AGAIN BY 12Z WHILE KGLD
WILL BE SLOWER TO IMPROVE WITH MVFR CONDITIONS AFTER ABOUT 14Z.
LOCKHART
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
KS...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
937 PM MST THU FEB 9 2012
.DISCUSSION...
225 PM MST THU FEB 9 2012
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS HIGHLY
AMPLIFIED RIDGE ACROSS THE PACIFIC COAST AND A LARGE SCALE TROUGH
ACROSS SOUTHERN CANADA/NORTHERN GREAT LAKES. A SHORTWAVE TROUGH
BETWEEN THESE FEATURES EXTENDS ACROSS THE NORTHERN PLAINS...WITH
ITS MEAN AXIS ALONG THE COLORADO/KANSAS STATE LINE.
TONIGHT...THE UPPER TROUGH CURRENTLY MOVING OVER THE CENTRAL HIGH
PLAINS REGION MOVES EAST OF THE AREA TONIGHT. SUBSIDENCE AND
DRYING ALOFT MOVE OVER IN THE WAKE OF THE TROUGH WITH A GENERAL
DECREASE IN SKY COVER. HIGH PRESSURE OVER THE NORTHERN PLAINS
BEGINS TO MOVE INTO THE REGION WITH WINDS REMAINING OUT OF THE
NORTH-NORTHWEST. WITH A COLDER AREA OF HIGH PRESSURE MOVING
IN...EXPECT TEMPERATURES TONIGHT AND EARLY FRIDAY TO BE NEARLY 10
TO 15 DEGREES COOLER AT MOST LOCATIONS ACROSS THE FORECAST AREA.
LOCKHART
FRIDAY-SUNDAY...COLD AIRMASS SETTLES IN OVER CWA AS A COLD FRONT
MOVES SOUTH OVER CWA AND STRONG SURFACE HIGH BUILDS OVER NORTHERN
PLAINS. A LARGE TEMPERATURE GRADIENT WILL SET UP ACROSS THE SW
PART OF THE CWA. WHILE TEMPS IN THE EXTREME SW CWA MAY REMAIN NEAR
NORMAL DURING THESE PERIODS...THE REST OF THE AREA WILL EXPERIENCE
DAYTIME TEMPS BELOW FREEZING.
DEEP EASTERLY UPSLOPE DEVELOPS BY FRIDAY EVENING WITH ATMOSPHERE
SATURATING BENEATH H7 ACROSS THE CWA. BETTER MID LEVEL MOISTURE/LIFT
WILL SUPPORT SNOW MAINLY OVER THE NORTHERN PART OF THE CWA FRIDAY
NIGHT WHERE AROUND AN INCH OF SNOW IS EXPECTED. BIGGER STORY MAY END
UP BEING THE POTENTIAL FOR FREEZING DRIZZLE AND FREEZING FOG FROM
THE BL TO H7 AROUND -10C FOR MUCH OF THESE PERIODS. THIS COULD
SUPPORT BOTH SUPER COOLED LIQUID AS WELL AS ICE CRYSTALS IN
LOCATIONS IN THE WEST WHERE MID LEVELS ARE MUCH DRIER. THERE
SHOULD ALSO BE BETTER CHANCES FOR DENSE FOG/FREEZING DRIZZLE IN
THE WEST WHERE MOISTURE POOLING ALONG BAROCLINIC ZONE IS MORE
LIKELY. FOR NOW NOT EXPECTING A LOT OF ICE ACCUMULATION...THOUGH A
FEW HUNDREDTHS OF AN INCH COULDNT BE RULED OUT IN THE WEST. IN ANY
CASE A PERIOD OF LIGHT MIXED PRECIP/FOG/LOW STRATUS LOOKS TO BE IN
STORE FRIDAY NIGHT THROUGH EARLY SATURDAY MORNING.
STRATUS/FOG POTENTIAL WILL CONTINUE THROUGH SATURDAY NIGHT/EARLY
SUNDAY MORNING...WITH LITTLE CHANGING IN REGARDS TO UPSLOPE FLOW AND
SURFACE HIGH PRESSURE. AS WEAK SHORTWAVE ENERGY CONTINUES TO PASS
AROUND GREAT LAKES UPPER LOW...I CANT RULE OUT SNOW ACROSS THE
EASTERN CWA THROUGH SUNDAY NIGHT...WHERE I KEPT SLIGHT CHANCE POPS
IN PLACE.
MONDAY-MONDAY NIGHT...SHORTWAVE RIDGE BUILDS IN FROM THE WEST...WHICH
SHOULD HELP BRING NEAR NORMAL TEMPS BACK TO CWA. GUIDANCE STILL
INDICATING LIFT/MOISTURE LINGERING OVER EASTERN PART OF THE CWA...SO
I KEPT SLIGHT CHANCE POPS GOING THROUGH THE DAY. IF OTHER GUIDANCE
TRENDS TOWARDS FASTER NAM SOLUTION THESE POPS COULD PROBABLY BE
REMOVED.
TUESDAY-THURSDAY...NOT A LOT OF CONFIDENCE IN THE FORECAST DURING
THESE PERIODS WITH A LOT OF SPREAD IN REGARDS TO SMALLER SCALE
FEATURES WITHIN A FAIRLY CHAOTIC QUASI-ZONAL PATTERN. ECMWF AND GFS
CONTINUE TO DIFFER ON THE EVOLUTION OF SHORTWAVE TROUGHS ON
WEDNESDAY AND THURSDAY...WHERE BOTH MODELS HAVE BEEN TRYING TO
PRODUCE PRECIP FOR DIFFERENT PARTS OF THE CENTRAL HIGH PLAINS. ECMWF
HAS SHOWN BETTER RUN-RUN CONSISTENTLY THUS FAR...AND WOULD FAVOR A
DRY SOLUTION FOR OUR CWA. GFS CONTINUES TO FAVOR A WETTER
SOLUTION...BUT HAS BEEN LESS CONSISTENT ON THE PLACEMENT OF QPF
BETWEEN MODEL RUNS. FOR NOW I KEPT SLIGHT CHANCE POPS IN PLACE
WEDNESDAY THROUGH THURSDAY TO ACCOUNT FOR THE SPREAD IN SOLUTIONS
AND THE UNCERTAINTY AT THIS RANGE. WAS NOT CONFIDENT ENOUGH TO STRAY
TO FAR FROM NORM ON TEMPS CONSIDERING MODEL SPREAD EACH DAY.
DR
&&
.AVIATION...
937 PM MST THU FEB 9 2012
FOR THE 06Z TAFS...VFR AT BOTH TERMINALS THROUGH FRIDAY MIDDAY.
AFTERWARDS...EASTERLY UPSLOPE WINDS WILL LEAD TO MVFR STRATUS
FORMATION FIRST AT KMCK THEN AT KGLD. AFT 00Z...MID LEVEL FORCING
INCREASES AND WITH SATURATED LOW/MID LEVELS...LIGHT SNOW WILL
BECOME POSSIBLE...ESPECIALLY AT KGLD. IF LIGHT SNOW
MATERIALIZES...EXPECT POSSIBLE IFR CIGS/VIS THROUGH END OF TAF
PERIOD.
BAS
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
411 PM EST FRI FEB 10 2012
.Short Term (Today and Tonight)...
Updated at 317 PM EST Feb 10 2012
First in a series of mid-level wave continues to push eastward into
the lower Ohio Valley this afternoon. Out ahead of this feature,
widespread precipitation shield has been affecting southern Indiana
and central Kentucky this afternoon. Colder thermal profiles across
the north have resulted in precipitation remaining in the form of
snow. However, across southern Kentucky, slightly warmer air aloft
has worked into that region which has resulted in a mix of rain
and/or just plain rain in areas down around Bowling Green and
Glasgow. This band of precipitation continues to head east and will
likely clear the I-65 corridor by 5PM EST and the Bluegrass region
by 7-8 PM tonight. Temperatures this afternoon have warmed into the
upper 30s in the west and with lower 30s in the east. Temperatures
have been taking a dip when the snow bands have moved through...then
have rebounded by a couple of degrees once the precipitation had
ended. For the remainder of the afternoon...we expect temperatures
to remain close to their current values and actually rise a degree
or two once the precipitation has ended as southerly flow attempts
to bring a little warmer air into the area ahead of the approaching
cold front to the northwest of the region. Snowfall accumulations
of a dusting or so will be possible with this afternoon snow
activity...but do not be surprised to see it melt rather quickly
once the precipitation ends. With temps expected to remain above
freezing this afternoon and this evening...am not anticipating much
in the way of travel problems for the afternoon rush and for evening
activities.
For Tonight, the next weather feature will be a strong cold front
that will surge through the region. Currently the front out to our
west near St. Louis. The front has been moving a bit slower than
the models had been forecasting an it is expected to hit our area a
little later than previously forecast. As the front approaches,
temperatures will likely rise slightly and we`ll see a return of
snow showers. The front looks to pass through the I-65 corridor
between 11P-12A EST tonight and then through the I-75 corridor by
2-3AM. Colder air will quickly rush in behind the front and
temperatures will fall into the lower 20s by sunrise on Saturday.
The latest HRRR, our local Hi-Res ARW WRF, and RUC data all show
snow shower activity occurring ahead and behind the front. Vertical
sounding profiles actually have a bit of a convective look to them
and I would not be surprised to see more of a snow shower/snow
squall type of activity to develop later tonight. In addition, the
pressure gradient will really tighten up and winds of 15-20 MPH with
gusts up to 30 MPH will be possible. These snow showers will be the
ones that bring the accumulating snow to the region. The snow
combined with temperatures falling into the lower 20s will result in
slick spots developing later tonight. Therefore we will leave the
current winter weather advisory intact...though much of the expected
snowfall and hazardous travel conditions will be delayed until later
tonight and into Saturday morning.
The front will continue to surge eastward on Saturday and
precipitation will end from west to east during the morning hours.
The models are trying to develop a fetch off of Lake Michigan.
However, the models have been often too aggressive with these during
this winter. Nonetheless...some snow shower activity looks to
persist into the morning hours on Saturday and that will likely add
a little more accumulation over in the Bluegrass region. Skies will
likely remain mostly cloudy through much of the day with
temperatures remaining in the 20s. Surface winds will remain
elevated during the day with winds of 10-20 MPH and gusts up to 25
MPH or so. This will keep wind chills down in the single digits at
times on Saturday.
As far as snowfall accumulations...the consensus guidance suggests
around an inch of accumulation for areas generally north of the WK
and BG Parkways. Little accumulation is expected in the far south
and southwest where a 1/2 inch or less will be possible. Highest
accumulations are going to be in the northeast generally east of
U.S. 27 where 1-2 inches of snowfall will be possible by the time
precipitation comes to an end on Saturday.
.Long Term (Saturday Night - Friday)...
Updated at 300 PM EST Feb 10 2012
1040mb high pressure will be over the central Plains Saturday night,
with an equally significant low off the New England coast. The
gradient in between will mean northwesterly winds that will just
start to weaken some as the night progresses. By the day Sunday, the
high will move to around Arkansas, making the strongest winds over
the Bluegrass and weaker across the southwest forecast area.
Temperatures will remain chilly however, with readings only getting
up to around freezing for highs. Wind chills Sunday morning again
look to be in the single digits for most of the area.
The next weather system to impact the region still looks to be
Monday night. Multiple waves within a strengthening southwesterly
flow will allow for precip all along the MS river valley Monday
afternoon and expect this moisture to advect east for the night.
Given forecast temperatures, expect at least a wintry mix for the
night, if not all snow for the north. By midnight, most of the
region should be into light to moderate snow. We could have another
advisory level event over southern Indiana with still some potential
over norther central Kentucky, but it is too early to be that
specific.
The difference with this system, compared to tonight`s snows, will
be that it looks to be followed by some warming for midweek. Models
are still not handling the longer term that well, so do not have
high confidence at this point. The 12Z GFS had a vortmax cross the
region Wednesday that was not in the previous forecast. the 00Z
ECMWF and now the 12Z have hinted at this as well, but there is not
much moisture associated with the impulse. Conversely, the system
that was expected for Thursday has now backed off as well in the 12Z
GFS, but the new ECMWF continues with a large storm system moving
into the midwest. Given such run-to-run inconsistency, will keep in
some precip chances each day, though with lower pops. Also, have
leaned more towards the precip type as rain, with highs into the 50s
Wednesday through Friday.
&&
.Aviation (21Z TAF Issuance)...
Updated at 410 PM EST Feb 10 2012
Given the recent radar trends we have updated the TAF forecasts for
this evening. Mid-level trough axis to the west is forcing the
current precipitation across southern Indiana and central Kentucky.
This precipitation shield will continue to head to the east and will
exit the terminals in the next hour or so. Behind the precipitation
shield...cigs will likely remain MVFR with VFR visibilities.
Precipitation will redevelop later this evening as a strong cold
front pushes in from the northwest. Based on the current data...the
front should push through KSDF and KBWG around 11/03-05Z and then
through KLEX around 11/05-07Z. Snow showers and snow squalls are
likely to develop in advance and just behind the frontal boundary.
This will likely result in MVFR vsbys and cigs as the snow showers
move through...though I can`t rule out some tempo IFR conditions if
a heavier snow shower or squall impacts the terminal. Winds will
shift from the SW to the NW after frontal passage and winds of
12-18kts sustained and gusts of 24-28kts being possible later
tonight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
INZ076>078-083-084-089>092.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR INZ079.
KY...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
KYZ023>030-053>057-061>067-070>078-081-082.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR KYZ031>043-
045>049.
$$
Short Term.......MJ
Long Term........RJS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
318 PM EST FRI FEB 10 2012
.Short Term (Today and Tonight)...
Updated at 317 PM EST Feb 10 2012
First in a series of mid-level wave continues to push eastward into
the lower Ohio Valley this afternoon. Out ahead of this feature,
widespread precipitation shield has been affecting southern Indiana
and central Kentucky this afternoon. Colder thermal profiles across
the north have resulted in precipitation remaining in the form of
snow. However, across southern Kentucky, slightly warmer air aloft
has worked into that region which has resulted in a mix of rain
and/or just plain rain in areas down around Bowling Green and
Glasgow. This band of precipitation continues to head east and will
likely clear the I-65 corridor by 5PM EST and the Bluegrass region
by 7-8 PM tonight. Temperatures this afternoon have warmed into the
upper 30s in the west and with lower 30s in the east. Temperatures
have been taking a dip when the snow bands have moved through...then
have rebounded by a couple of degrees once the precipitation had
ended. For the remainder of the afternoon...we expect temperatures
to remain close to their current values and actually rise a degree
or two once the precipitation has ended as southerly flow attempts
to bring a little warmer air into the area ahead of the approaching
cold front to the northwest of the region. Snowfall accumulations
of a dusting or so will be possible with this afternoon snow
activity...but do not be surprised to see it melt rather quickly
once the precipitation ends. With temps expected to remain above
freezing this afternoon and this evening...am not anticipating much
in the way of travel problems for the afternoon rush and for evening
activities.
For Tonight, the next weather feature will be a strong cold front
that will surge through the region. Currently the front out to our
west near St. Louis. The front has been moving a bit slower than
the models had been forecasting an it is expected to hit our area a
little later than previously forecast. As the front approaches,
temperatures will likely rise slightly and we`ll see a return of
snow showers. The front looks to pass through the I-65 corridor
between 11P-12A EST tonight and then through the I-75 corridor by
2-3AM. Colder air will quickly rush in behind the front and
temperatures will fall into the lower 20s by sunrise on Saturday.
The latest HRRR, our local Hi-Res ARW WRF, and RUC data all show
snow shower activity occurring ahead and behind the front. Vertical
sounding profiles actually have a bit of a convective look to them
and I would not be surprised to see more of a snow shower/snow
squall type of activity to develop later tonight. In addition, the
pressure gradient will really tighten up and winds of 15-20 MPH with
gusts up to 30 MPH will be possible. These snow showers will be the
ones that bring the accumulating snow to the region. The snow
combined with temperatures falling into the lower 20s will result in
slick spots developing later tonight. Therefore we will leave the
current winter weather advisory intact...though much of the expected
snowfall and hazardous travel conditions will be delayed until later
tonight and into Saturday morning.
The front will continue to surge eastward on Saturday and
precipitation will end from west to east during the morning hours.
The models are trying to develop a fetch off of Lake Michigan.
However, the models have been often too aggressive with these during
this winter. Nonetheless...some snow shower activity looks to
persist into the morning hours on Saturday and that will likely add
a little more accumulation over in the Bluegrass region. Skies will
likely remain mostly cloudy through much of the day with
temperatures remaining in the 20s. Surface winds will remain
elevated during the day with winds of 10-20 MPH and gusts up to 25
MPH or so. This will keep wind chills down in the single digits at
times on Saturday.
As far as snowfall accumulations...the consensus guidance suggests
around an inch of accumulation for areas generally north of the WK
and BG Parkways. Little accumulation is expected in the far south
and southwest where a 1/2 inch or less will be possible. Highest
accumulations are going to be in the northeast generally east of
U.S. 27 where 1-2 inches of snowfall will be possible by the time
precipitation comes to an end on Saturday.
.Long Term (Saturday Night - Friday)...
Updated at 300 PM EST Feb 10 2012
1040mb high pressure will be over the central Plains Saturday night,
with an equally significant low off the New England coast. The
gradient in between will mean northwesterly winds that will just
start to weaken some as the night progresses. By the day Sunday, the
high will move to around Arkansas, making the strongest winds over
the Bluegrass and weaker across the southwest forecast area.
Temperatures will remain chilly however, with readings only getting
up to around freezing for highs. Wind chills Sunday morning again
look to be in the single digits for most of the area.
The next weather system to impact the region still looks to be
Monday night. Multiple waves within a strengthening southwesterly
flow will allow for precip all along the MS river valley Monday
afternoon and expect this moisture to advect east for the night.
Given forecast temperatures, expect at least a wintry mix for the
night, if not all snow for the north. By midnight, most of the
region should be into light to moderate snow. We could have another
advisory level event over southern Indiana with still some potential
over norther central Kentucky, but it is too early to be that
specific.
The difference with this system, compared to tonight`s snows, will
be that it looks to be followed by some warming for midweek. Models
are still not handling the longer term that well, so do not have
high confidence at this point. The 12Z GFS had a vortmax cross the
region Wednesday that was not in the previous forecast. the 00Z
ECMWF and now the 12Z have hinted at this as well, but there is not
much moisture associated with the impulse. Conversely, the system
that was expected for Thursday has now backed off as well in the 12Z
GFS, but the new ECMWF continues with a large storm system moving
into the midwest. Given such run-to-run inconsistency, will keep in
some precip chances each day, though with lower pops. Also, have
leaned more towards the precip type as rain, with highs into the 50s
Wednesday through Friday.
&&
.Aviation (18Z TAF Issuance)...
Updated at 1231 PM EST Feb 10 2012
Precipitation shield continue to develop over southern Indiana and
Kentucky early this afternoon. Majority of the early precipitation
will likely affect KSDF and KLEX. Cigs and visibilities will likely
jump around as mesoscale bands of light to moderate snow push
through the terminals. For now...we plan on MVFR cigs/vsbys as
prevailing with some tempo drops in visibility to IFR as the bands
affect the terminals. More widespread snow is forecast to develop
later this afternoon with much of the activity likely taking place
after 10/21Z. Further south down at KBWG...a slightly warmer
atmosphere in place will likely result in precipitation being in the
form of a rain/snow mix early this afternoon transitioning over to
all snow by 10/23Z or so. Cigs and vsbys should remain primarily
VFR at BWG this afternoon but drop to MVFR around 10/23 to 11/00Z.
Surface winds will remain out of the southwest this afternoon with
speeds of 4-7 knots. Winds are expected to shift to the northwest
tonight...probably around 11/05-06Z as a strong cold front moves
through. The pressure gradient will also increase late tonight
resulting in winds picking up quite a bit. Northwest winds of
14-18kts are expected and gusts to 28kts will be possible late
tonight through Saturday morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
INZ076>078-083-084-089>092.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR INZ079.
KY...WINTER WEATHER ADVISORY UNTIL NOON EST /11 AM CST/ SATURDAY FOR
KYZ023>030-053>057-061>067-070>078-081-082.
WINTER WEATHER ADVISORY UNTIL NOON EST SATURDAY FOR KYZ031>043-
045>049.
$$
Short Term.......MJ
Long Term........RJS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
826 PM EST SAT FEB 11 2012
.SYNOPSIS...
BLUSTERY NORTHWEST WINDS WILL MAINTAIN SNOW SHOWERS AND BLOWING
SNOW INTO EARLY SUNDAY MORNING, AND CAUSE SUBZERO WIND CHILL.
INCOMING MIDWEST HIGH PRESSURE WILL PROVIDE MODERATING TEMPERATURES
MONDAY AFTERNOON.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
WILL ALLOW ADVISORY FOR ZANESVILLE AREA TO EXPIRE AS MAIN BANDS OF
SNOW ARE EAST OF THAT REGION. MAIN BAND OF HEAVY SNOW CONTINUES
FROM COLUMBIANA COUNTY TO NEAR STEUBENVILLE AND SOUTH ACROSS
WASHINGTON COUNTY AND INTO THE RIDGES. THIS BAND HAS PRODUCED
RATES OVER AN INCH AN HOUR LAST 3-4 HOURS BUT IS BEGINNING TO
BREAK DOWN AS SHORTWAVE BEGINNING TO MOVE SOUTH ACROSS EASTERN
LAKES APPROACHES TO DISTURB FLOW. BANDS WILL CONTINUE ACROSS
GREATER PITTSBURGH REGION BEFORE DIMINISHING FOR A TIME LATE
EVENING AHEAD OF SHORTWAVE. PREVIOUS POPS SEEM IN LINE OVERALL.
PREVIOUS DISCUSSION FOLLOWS.
PER BLEND OF RECENT SURFACE AND RADAR DATA COUPLED WITH HRRR AND
NAM MODEL OUTPUT, EXPECT COLD BLUSTERY NORTHWEST WINDS TO PROVIDE
SNOW SHOWERS AND BLOWING SNOW FOR THE UPPER OHIO VALLEY EAST OF
THE OHIO LINE INTO EARLY SUNDAY MORNING. SO HAVE MAINTAINED THE
WINTER WEATHER HEADLINES.
WIND GUSTS ACROSS THE HIGHER MOUNTAINS CAN APPROACH 45 MPH,
ELSEWHERE 35-40 MPH. WITH TEMPERATURES IN THE TEENS, EXPECT WIND
CHILLS TO GO SUBZERO. ACROSS THE HIGHER MOUNTAINS, WIND CHILL CAN
GO TO MINUS 15, SO HAVE ADDED WIND CHILL ADVISORY THERE THROUGH
SUNDAY MORNING.
REGARDING SNOW SHOWER DETAILS, RECENT WRF-NMM AND HRRR SHOW THE
LAKE EFFECT SNOW BANDS SHIFTING SOUTH. ALSO NAM MODEL PROFILES
SHOW THE SUBSIDENCE INVERSION CAN LOWER, SO SNOW SHOWER INTENSITY
SHOULD DECREASE LATE TONIGHT. HOWEVER KEPT SNOW SHOWERS ACROSS THE
HIGHER ELEVATIONS, AS OROGRAPHIC INFLUENCES SOMETIMES MAINTAIN
SNOW SHOWERS LONGER THEN EXPECTED.
TEMPERATURE AND WIND DETAILS WERE BASED ON CONSENSUS OF GFS LAMP
AND NAM MODEL OUTPUT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
RECENT NAM AND GFS MODEL OUTPUT SHOW HIGH PRESSURE PROVIDING DRY
CONDITIONS SUNDAY NIGHT INTO MONDAY NIGHT. TEMPERATURES WILL STILL
BE QUITE COLD INTO MONDAY MORNING, BUT THEN MODERATE TO WITHIN 5
DEGREES OF NORMAL MONDAY AFTERNOON.
MODELS THEN SHOW A WEAK LOW PRESSURE SYSTEM, COMING EAST FROM THE
PLAINS TO PROVIDE MIX OF SNOW AND RAIN SHOWERS TUESDAY, WITH
TEMPERATURES TUESDAY AFTERNOON NEAR NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GENERALLY FOLLOWED EC AND HPC GUIDANCE. HIGH PRESSURE ACROSS REGION
WEDNESDAY WITH FAIR WEATHER. MODELS CONTINUE TO STRUGGLE WITH
STRENGTH OF LOW PRESSURE MOVING THROUGH OHIO RIVER VALLEY ON
THURSDAY...BUT EXPECT MOSTLY RAIN ON THURSDAY WITH SOME SNOW
POSSIBLE ACROSS FAR NORTH. BY FRIDAY SYSTEM IS WELL EAST OF AREA
WITH CHANCE OF SNOW SHOWERS IN NORTHWEST FLOW. HIGH PRESSURE
REMAINS WEST OF REGION WITH NORTHWEST FLOW. THIS SHOULD KEEP SOME
CLOUDINESS OF REGION...BUT LACK OF COLD AIR PRECLUDES SNOW SHOWER
ACTIVITY SATURDAY.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
EXPECT GENERALLY MVFR RESTRICTIONS TO PREVAIL OVERNIGHT AS
NORTHWEST FLOW ACROSS THE GREAT LAKES CONTINUES TO GENERATE SNOW
SHOWERS ACROSS THE REGION. CONDITIONS WILL OCCASIONALLY LOWER TO
IFR ACROSS WESTERN PA TERMINALS IN HEAVIER SNOW BANDS.
AREA COVERAGE OF SNOW SHOWERS AND RESTRICTIONS MAY BECOME MORE
SCATTERED FOR A FEW HOURS EARLY TONIGHT. COVERAGE OF SNOW SHOWERS
IS FORECAST TO INCREASE AGAIN AFTER 06Z AS AN APPROACHING SHORT
WAVE TROUGH BRINGS ANOTHER SHOT OF MOISTURE INTO THE REGION.
A LOWERING INVERSION LAYER WILL GREATLY INHIBIT CONVECTION AFTER
15Z SUNDAY. BROKEN STRATOCUMULUS WILL GRADUALLY LIFT TO AROUND 3000
FEET IN THE AFTERNOON.
OUTLOOK...MONDAY THROUGH THURSDAY...
BUILDING HIGH PRESSURE WILL RETURN BY MONDAY WITH VFR CONDITIONS.
SHORTWAVE IN ZONAL FLOW IS PROGGED TO GENERATE MORE LIGHT SNOW BY
EARLY TUESDAY. AT LEAST MVFR CAN BE EXPECTED WITH THAT SYSTEM.
REBUILDING HIGH PRESSURE WILL RETURN VFR BY LATE TUESDAY AND
WEDNESDAY.
A STRONGER SYSTEM IS PROGGED TO MOVE THROUGH THE REGION ON
THURSDAY WITH LOW PASSING WEST OF THE FORECAST AREA. RAIN SHOULD
REACH WESTERN TERMINALS THURSDAY MORNING AND SPREAD ACROSS REGION
BY AFTERNOON WITH CONDITIONS DETERIORATING TO MVFR.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ001.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR MDZ001.
OH...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR OHZ040-041-
049-050-059-069.
PA...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR PAZ007>009-
013>016-020>023-029-031-073-075.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR PAZ074-076.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR WVZ001>004-
012-021-022.
WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ023-041.
WIND CHILL ADVISORY UNTIL NOON EST SUNDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1257 PM EST FRI FEB 10 2012
.SYNOPSIS...
LOW PRESSURE AND AN ARCTIC COLD FRONT WILL BRING SNOW TONIGHT AND
SATURDAY, FOLLOWED BY COLD TEMPERATURES AND SCATTERED SNOW SHOWERS INTO
SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
HAVE ISSUED WINTER STORM WARNING FOR THE HIGHER MOUNTAINS AND
WINTER WEATHER ADVISORIES FOR THE REST OF THE UPPER OHIO VALLEY
STARTING TONIGHT.
HAVE TWEAKED FORECAST FOR THIS AFTERNOON BASED ON RECENT SURFACE
DATA AND HRRR MODEL OUTPUT. CONTINUE TO EXPECT FIRST SNOW TO BEGIN
LATE AFTERNOON, MAINLY SOUTH OF I-70.
PER RECENT NAM, GFS AND CONSENSUS OF OTHER SREF MODEL OUTPUT,
EXPECT TWO EPISODES OF SNOWFALL. THE FIRST SNOW EPISODE, WILL BE
ASSOCIATED WITH A LOW PRESSURE CENTER PASSING EASTWARD THROUGH THE
CENTRAL APPALACHIAN MOUNTAINS, AND SO SHOULD MAINLY AFFECT
LOCATIONS SOUTH OF PITTSBURGH THIS EVENING. MOST LOCATIONS WILL
GET UP TO AN INCH. HOWEVER, THIS CAN BE ENOUGH TO CAUSE UNTREATED
PAVEMENTS TO BECOME SNOW COVERED AND SLIPPERY, WHICH CAN HAVE AN
IMPACT ON FRIDAY EVENING TRAVELERS.
THE SECOND SNOW EPISODE WILL BE ASSOCIATED WITH A LOW PRESSURE
SYSTEM THAT WILL MOVE SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY
LATE TONIGHT AND SATURDAY. THIS SYSTEM WILL DRIVE A STRONG COLD
FRONT THROUGH THE AREA SATURDAY. THE LIFT AND INSTABILITY
ASSOCIATED WITH THE SYSTEM, SHOULD ADD 2-3 INCHES OF SNOW
ACCUMULATION DAYTIME SATURDAY. WINDS CAN GUST OVER 30 MPH, AND SO
CAUSE BLOWING SNOW.
FORECASTED TEMPERATURES USING GFS LAMP AND NAM AND GFS MOS, WHICH
SHOWED TEMPERATURES SATURDAY CAN BE STEADY IN THE MORNING AND
SLOWLY FALLING IN THE AFTERNOON.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
PER RECENT NAM AND GFS MODEL OUTPUT, EXPECT POST FRONTAL,
NORTHWEST-FLOW LAKE-ENHANCED, SNOW SHOWERS TO AFFECT LOCATIONS
EAST OF I-77 SATURDAY NIGHT. NAM MODEL PROFILES SHOW A SUBSIDENCE
INVERSION CAPPING THE INSTABILITY AT 5 KFT AGL SUNDAY, SO SNOWFALL
SHOULD BE LESS DAYTIME SUNDAY, AND END SUNDAY NIGHT. DECIDED TO GO
WITH 7 AM SUNDAY AS CUTOFF FOR WINTER WEATHER HEADLINES.
FORECASTED TEMPERATURES TO BE NEARLY 10 DEGREES COLDER THAN
NORMAL INTO MONDAY MORNING. HIGHS MONDAY AFTERNOON MAY MODERATE TO
WITHIN 5 DEGREES OF NORMAL AS COLD TEMPERATURES WILL HAVE EXITED
WITH INCOMING HIGH PRESSURE.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AN UNSETTLED PATTERN WILL PERSIST THROUGH THE WEEK. LOW PRESSURE
WILL MOVE ACROSS THE EASTERN UNITED STATES MONDAY NIGHT INTO
TUESDAY. HIGH PRESSURE SHOULD ALLOW FOR A BRIEF DRY PERIOD ON
WEDNESDAY BEFORE ANOTHER LOW ARRIVES ON THURSDAY. TEMPERATURES
SHOULD BE NEAR CLIMATOLOGY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
LIGHT SNOW AHEAD OF A COLD FRONT WILL PUSH INTO THE TERMINALS SOUTH OF
KFKL/KDUJ EARLY THIS EVENING, THEN REACH KFKL/KDUJ AFTER 00Z.
PREVAILING MVFR VISIBILITY AND CEILING RESTRICTIONS WITH TEMPO
GROUPS FOR IFR VISIBILITIES ARE FORECAST WITH SNOW THIS EVENING.
PREVAILING VISIBILITIES WITH SNOW WILL LOWER TO IFR OVERNIGHT WITH
CEILINGS PREVAILING AT IFR BY DAWN ON SATURDAY. WINDS WILL BE
SOUTHWESTERLY AROUND 10KTS OVERNIGHT.
THE COLD FRONT WILL REACH THE TERMINALS BETWEEN DAWN AND THE
MID-MORNING HOURS. ALONG AND JUST AHEAD OF THE FRONT, A BURST OF
MORE MODERATE SNOW CAN BE EXPECTED WITH IFR RESTRICTIONS FORECAST
AND LOWER CONDITIONS POSSIBLE. AS THE FRONT PUSHES EAST OF THE AREA,
WINDS WILL SHIFT TO NORTHWESTERLY, INCREASING TO 15KTS WITH GUSTS UP
TO 25-30KTS. SCATTERED SNOW SHOWERS WITH IFR RESTRICTIONS CAN BE
EXPECTED FOR THE REMAINDER OF SATURDAY.
OUTLOOK...SATURDAY NIGHT THROUGH WEDNESDAY...
A COLD NORTHWESTERLY FLOW WILL ALLOW FOR SCATTERED SNOW SHOWERS WITH
IFR RESTRICTIONS TO CONTINUE SATURDAY NIGHT AND MOSTLY TAPER OFF BY
SUNDAY MORNING. A FEW LINGERING SNOW SHOWERS WITH VISIBILITY
RESTRICTIONS WILL BE POSSIBLE ON SUNDAY. IFR CEILING RESTRICTIONS
WILL PREVAIL EARLY SUNDAY AND LIFT TO MVFR LATE IN THE DAY. HIGH
PRESSURE WILL THEN BUILD IN ON MONDAY WITH VFR CONDITIONS RETURNING
BRIEFLY.
THE NEXT DISTURBANCE WILL MOVE ACROSS THE TERMINALS MONDAY NIGHT
INTO TUESDAY WITH THE CHANCE OF SNOW ALONG WITH RESTRICTIONS. HIGH
PRESSURE WILL THEN BUILD IN FOR WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY
FOR MDZ001.
OH...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST
SATURDAY FOR OHZ039-048-057-058-068.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR OHZ040-041-049-050-059-069.
PA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
SUNDAY FOR PAZ007>009-013>016-022-023.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR PAZ020-021-029-031-073-075.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY
FOR PAZ074-076.
WV...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
SUNDAY FOR WVZ001>004-012-021-022.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY
FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
425 PM EST FRI FEB 10 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
WV IMAGERY AND RUC ANALYSIS INDICATED CENTER OF THE POLAR VORTEX
EAST OF HUDSON BAY WITH A MID/UPPER LEVEL TROUGH AIX TO THE
SOUTHWEST THROUGH ERN LAKE SUPERIOR INTO CTNRL WI. AT THE SFC...A
1046 MB ARCTIC HIGH WAS LOCATED OVER SASK WITH A RIDGE EXTENDING
INTO NRN ONTARIO AND THROUGH THE PLAINS. NNW WINDS IN THE VERY COLD
AIRMASS SUPPORTED LES FOR LOCATIONS FAVORED BY NRLY WINDS.
HOWEVER...LES WAS DIMINISHING AND BANDS WERE SHIFTING WITH THE ACYC
FLOW...BACKING WINDS AND VERY DRY AIR WELL MIXED LOW LEVEL AIR
UPSTREAM WITH SFC DEWPOINTS TO NEAR -20F.
TONIGHT...WITH 850MB TEMPS AROUND -20C...LES WILL BE ONGOING IN
AREAS FAVORED BY NW WINDS. THE DRY AIR AND LOW INVERSION AOB 3KFT
WILL KEEP LES LIGHT INITIALLY. HOWEVER...WITH THE DENDRITIC SNOW
GROWTH TEMP ZONE (DGZ) FIRMLY IN THE CONVECTIVE LAYER...SHOULD STILL
BE ABLE TO GET A FEW INCHES OF FLUFFY SNOW MAINLY OVER THE NE FCST
AREA WHERE ENOUGH MOISTENING CAN OCCUR DESPITE THE DRY AIR.
WINDS OVER FAR SW UPPER MI MAY BACK SUFFICIENTLY TO CUT OVERWATER
TRAJECTORIES ENOUGH TO ALLOW FOR SOME CLEARING. EXPECT TEMPS THERE
TO FALL INTO THE SINGLE DIGITS BLO ZERO. ELSEWHERE...TEMPS ARE
EXPECTED TO REMAIN IN THE SINGLE DIGITS AND LOWER TEENS AS SFC-925MB
WINDS GENERALLY MAINTAIN SOME MODIFICATION OFF OF LAKE SUPERIOR.
SATURDAY...EXPECT LES INTENSITY TO INCREASE BY SAT AFTERNOON AS
850-700 MB MOISTURE INCREASES IN A DEVELOPING WAA PATTERN. WITH
850MB TEMPS MODERATING THROUGH THE DAY THE DGZ WILL CLIMB...BECOMING
MORE FAVORABLY POSITIONED IN THE CONVECTIVE LAYER/UPWARD MOTION
REGION. LONGER FETCH AND LONGER DURATION OF MORE FAVORABLE LES
PARAMETERS SUGGEST BEST SNOW ACCUMULATIONS WILL BE OVER THE NE FCST
AREA...WHERE AMOUNTS IN THE 2 TO 4 INCH RANGE ARE EXPECTED.
OVER WRN LAKE SUPERIOR...FLOW IS MORE WESTERLY AND ENHANCED
CONVERGENCE COULD DEVELOP BTWN THE PORCUPINE MTNS AND HOUGHTON. THIS
AREA OVER THE WRN CWA COULD ALSO SEE INCREASE IN LES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 423 PM EST FRI FEB 10 2012
CURRENT PUSH OF ARCTIC AIR INTO THE UPPER LAKES WILL BE SHORT LIVED
AS POLAR VORTEX E OF HUDSON BAY RETREATS/REFORMS BACK TOWARD THE
POLE NEXT WEEK. THE RETREAT OF THE NRN STREAM AND A DISTINCT SPLIT
FLOW REGIME NEXT WEEK WILL BRING A RETURN OF THIS WINTERS PREVAILING
THEME OF ABOVE NORMAL TEMPS. WHETHER OR NOT THIS SPLIT FLOW LEADS TO
ANY SRN STREAM SYSTEMS REACHING THE UPPER GREAT LAKES REMAINS TO BE
SEEN. AT THIS POINT...IT STILL APPEARS THAT THE OVERALL DRY PATTERN
WILL PERSIST NEXT WEEK THOUGH THERE ARE MUCH INCREASED UNCERTAINTIES
IN POSSIBLE STREAM INTERACTIONS THAT MAY LEAD TO SOME STORMINESS IN
THE GREAT LAKES LATE IN THE WEEK.
BEGINNING SAT NIGHT...TROF ASSOCIATED WITH POLAR VORTEX E OF HUDSON
BAY WILL BEGIN SHIFTING E...RESULTING IN THE BEGINNINGS OF A WAA
REGIME WHICH WILL CONTINUE THRU SUN. LES WILL BE ONGOING SAT EVENING
OVER THE E AT LOCATIONS FAVORED BY A WNW/NW WIND OFF LAKE SUPERIOR.
HOWEVER...INVERSION QUICKLY SETTLES DOWN TO 4KFT OR LWR LATE EVENING
AND OVERNIGHT. ALSO...WAA BEGINS TO SHIFT DENDRITIC SNOW GROWTH TEMP
ZONE (DGZ) UP ABOVE BEST UPWARD MOTION. IN GENERAL...MIGHT SEE
ANOTHER 1-2 MAYBE 3 INCHES OF SNOW OVER THE NE FCST AREA SAT NIGHT.
OUT W...INVERSION WILL ALREADY BE SETTLING TO 3KFT OR LWR EARLY IN
THE EVENING WITH DGZ ABOVE THE INVERSION. GIVEN THE LOW INVERSION
AND MODERATING AIRMASS...THERE MAY NOT BE MUCH LEFT OTHER THAN
FLURRIES SAT EVENING WITH GRADUAL CLEARING THEN FOLLOWING DURING THE
NIGHT FROM THE W. FROM AN ISENTROPIC STANDPOINT...CONDENSATION PRES
DEFICITS ARE QUITE HIGH SAT NIGHT IN DEVELOPING WAA REGIME...SO
THERE SHOULDN`T BE MUCH IN THE WAY OF WAA CLOUDINESS. ALTHOUGH SKIES
WILL BE CLEARING FROM THE W...MAY NOT BE ABLE TO DECOUPLE COMPLETELY
AS A STRONG PRESSURE GRADIENT STILL EXISTS BETWEEN A 1040MB HIGH
SINKING INTO THE CENTRAL PLAINS AND A 1008MB TROUGH OVER WESTERN
HUDSON BAY/FAR NRN ONTARIO. MINS SHOULD END UP NEAR ZERO IN THE
TRADITIONAL COLD SPOTS OVER THE INTERIOR W HALF...RANGING UP TO THE
TEENS E NEAR LAKE SUPERIOR.
LINGERING LIGHT LES OVER THE NE FCST AREA WILL END SUN AS INVERSION
CONTINUES TO LWR AND MORE IMPORTANTLY TEMPS AT INVERSION BASE RISE
ABOVE -10C. AWAY FROM DIMINISHING LIGHT LES E...SUN SHOULD TURN OUT
TO BE A MAINLY SUNNY DAY UNDER A DEEP DRY AIR MASS. DRY AIR MASS AND
SUNSHINE WORKING ON THE LWR ALBEDO FORESTED LANDSCAPE OF UPPER MI
WILL ASSIST THE WARM UP...BUT STRONG INVERSION WILL HOLD BACK THE
WARMING POTENTIAL OVER WHAT IT COULD BE. FCST SOUNDINGS SUGGEST
MIXING TO 900MB...BUT THAT MIGHT BE A LITTLE OPTIMISTIC. MID/UPPER
20S SHOULD BE THE RULE.
POLAR VORTEX WILL BE RETREATING MON WITH UPSTREAM SPLIT FLOW
ADVANCING INTO THE CNTRL CONUS. IN THE SPLIT...MODEL GUIDANCE
CONTINUES TO INDICATE A SRN STREAM SHORTWAVE MOVING INTO THE MID
MISSISSIPPI VALLEY LATE MON. THERE HASN`T BEEN MUCH MODEL SPREAD
WITH THIS SYSTEM IN RECENT RUNS...AND LATEST ROUND OF GUIDANCE
MAINTAINS THE IDEA THAT THE BULK OF ASSOCIATED PCPN WILL PASS S OF
UPPER MI. SEE NO REASON TO STRAY FROM THAT SCENARIO RIGHT NOW.
SO...CLEAR SKIES SUN NIGHT WILL GIVE WAY TO A SLOW INCREASE IN
HIGH/MID CLOUDS FROM THE SW MON. MAINTAINED SLIGHT CHC POPS ACROSS
THE FAR S/SE MON NIGHT AS THE NRN FRINGE OF PCPN MAY BRUSH THAT
AREA.
TUE THRU FRI...UNDER SPLIT FLOW WITH MORE PROGRESSIVE NRN STREAM...
ARCTIC AIR WILL BE BOTTLED UP WELL TO THE N DURING THE MIDDLE AND
END OF NEXT WEEK. BENIGN/DRY WEATHER SHOULD CONTINUE TUE/WED. EVEN
LES WON`T BE A CONCERN WITH CONSENSUS 850MB TEMPS WARMER THAN -8C.
HEADING INTO THU/FRI...SOME RECENT GFS RUNS HAVE SUGGESTED POSSIBLE
STREAM INTERACTIONS SOMEWHERE FROM THE MISSISSIPPI VALLEY EASTWARD
THAT COULD LEAD TO A STORM SYSTEM IN THE GREAT LAKES AREA. TODAYS
12Z ECMWF RUN IS NOW BEGINNING TO SUGGEST THAT AS WELL. AS ALWAYS...
THERE IS LOW CONFIDENCE IN STREAM PHASING...AND IT GOES WITHOUT
SAYING THAT THERE IS TREMENDOUS UNCERTAINTY IN ANY TYPE OF
INTERACTION THAT FAR OUT IN A MODEL RUN. WILL BE SOMETHING TO
MONITOR IN THE COMING DAYS...BUT FOR NOW...FAVORED THE MORE
DISTINCT...SEPARATED FLOW REPRESENTED BY PREVIOUS ECMWF RUNS. AS A
RESULT...MAINTAINED A DRY FCST FOR THU/FRI THOUGH THERE COULD BE A
LITTLE -SN AT SOME POINT. AIR MASS REMAINS WARM ENOUGH TO PRECLUDE
ANY MENTION OF LES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1224 PM EST FRI FEB 10 2012
EXPECT ALL SITES TO IMPROVE THIS AFTERNOON AS WINDS BACK TO THE NW
AND VERY DRY AIR UPSTREAM FROM LAKE SUPERIOR LIMITS ACTIVITY. LES IS
EXPECTED TO REDEVELOP AT CMX AND IWD OVERNIGHT AS MOISTURE INCREASES
AGAIN WITH NW FLOW. HOWEVER...MAINLY MVFR CONDITIONS WILL PREVAIL
WITH ONLY BRIEF PERIODS OF IFR POSSIBLE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EST FRI FEB 10 2012
NNW WINDS TO 30KT WILL PERSIST WITH AMPLE INSTABILITY IN THE ARCTIC
AIRMASS MOVING OVER THE REGION. NW WINDS APPROACHING GALES TO 35 KT
ARE ALSO POSSIBLE SAT AFTERNOON INTO SAT EVENING OVER ERN LAKE
SUPERIOR. EXPECT HEAVY FREEZING SPRAY ACROSS THE ENTIRE LAKE TONIGHT
THROUGH SAT NIGHT WITH THE STRONG WINDS AND WAVE ACTION. LOOK FOR
HEAVY FREEZING SPRAY TO END ON SUNDAY AS THE AIRMASS WARMS AND WINDS
GRADUALLY DIMINISH. CONDITIONS WILL QUIET DOWN FOR THE EARLY PART OF
THE WORK WEEK AS A HIGH PRES RIDGE MOVES OVER THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LMZ221-250.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1220 PM EST FRI FEB 10 2012
LATEST UPDATE...SHORT TERM AND MARINE...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(1220 PM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WENT AHEAD AND STARTED THE ADVISORY A LITTLE EARLIER THAN INITIALLY
INDICATED SINCE SNOW HAS ALREADY BEEN UNDERWAY FOR A FEW HOURS.
HOWEVER THE MAIN HAZARD... THE COLD AIR... IS A TAD DELAYED DUE A
WAVE ON THE FRONT. AT NOON THE FRONT WAS FROM JUST NORTH OF MUSKEGON
TO HOUGHTON LAKE... AND IS NOT PROJECTED INTO GRR UNTIL 4-5 PM. IT
MAY NOW HOLD OFF AT AZO/BTL/LAN UNTIL 7 PM.. AND PERHAPS 9 PM AT
JXN. THIS IS GOOD NEWS SINCE LOCATIONS SOUTH AND EAST OF GRR MAY BE
ABLE TO GET THROUGH THE BULK OF THE EVENING COMMUTE BEFORE THE
REALLY COLD ARRIVES AND ICES UP THE ROADS. THAT WOULD CERTAINLY HELP
LIMIT THE IMPACTS. ONE THING TO NOTE HOWEVER IS THAT SOME OF THE
SHORT TERM GUIDANCE IS LAGGING BEHIND AT THE INITIALIZATION WITH THE
ARCTIC AIR.. SO THE ARRIVAL OF THE COLD AIR COULD STILL BE EARLIER
THAN INDICATED ABOVE.
PREVIOUS DISCUSSION...
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMINISH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(1200 PM EST FRI FEB 10 2012)
MVFR TO IFR CONDITIONS AT ALL THE TERMINALS MAY TEMPORARILY DIP INTO
THE LIFR CATEGORY LATER THIS AFTN AND EARLY EVE AS SNOW INCREASES
NEAR THE ARCTIC FRONT. WINDS WILL INCREASE SIGNIFICANTLY AND VEER TO
THE NORTH RIGHT AFTER FROPA MID TO LATE AFTN INTO THE EVE AT ALL THE
TERMINALS. GUSTS WILL REACH 25 KTS AT ALL TERMINALS THROUGH THE
EVENING. HIGHER GUSTS TO 30 KTS ARE POSSIBLE PARTICULARLY AT KMKG.
SNOW SHOWERS WILL GRADUALLY END AT MOST OF THE TERMINALS OVERNIGHT
WITH MAINLY MVFR CONDITIONS LATE TONIGHT INTO SATURDAY DUE TO
LINGERING LOW CLOUDS. HOWEVER LAKE EFFECT SNOW SHOWERS WILL DEVELOP
OVERNIGHT AND IMPACT KMKG RESULTING IN MAINLY IFR CONDITIONS THERE.
AS LOW LEVEL WINDS BACK FROM THE NORTH TO THE NW SATURDAY MORNING I
EXPECT THAT THE LAKE EFFECT SNOW BAND WILL BEGIN TO PROPAGATE INLAND
AND POTENTIALLY REACH KGRR AND KAZO AND POINTS ALONG THE US-131
CORRIDOR TOWARD MIDDAY SATURDAY.
&&
.MARINE...(1220 PM EST FRI FEB 10 2012)
BIG SABLE POINT WAS ALREADY GUSTING TO GALE FORCE BEHIND THE FRONT
AT 11 AM... SO UPGRADED EARLIER TO A GALE WARNING THROUGH SATURDAY
MORNING.
AS TEMPS FALL BELOW FREEZING LATER THIS AFTERNOON AND TONIGHT...THE
GUSTY WINDS MAY RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THROUGH 10 PM FOR ALL BUT THE NORTHERN
TWO ROWS OF COUNTIES.
LM...GALE WARNING IN EFFECT THROUGH SATURDAY MORNING.
SMALL CRAFT ADVISORY SATURDAY MORNING THROUGH SUNDAY AFTERNOON.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93/MEADE
LONG TERM: MJS
AVIATION: LAURENS
MARINE: MEADE
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1200 PM EST FRI FEB 10 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(346 AM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMINISH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(1200 PM EST FRI FEB 10 2012)
MVFR TO IFR CONDITIONS AT ALL THE TERMINALS MAY TEMPORARILY DIP INTO
THE LIFR CATEGORY LATER THIS AFTN AND EARLY EVE AS SNOW INCREASES
NEAR THE ARCTIC FRONT. WINDS WILL INCREASE SIGNIFICANTLY AND VEER TO
THE NORTH RIGHT AFTER FROPA MID TO LATE AFTN INTO THE EVE AT ALL THE
TERMINALS. GUSTS WILL REACH 25 KTS AT ALL TERMINALS THROUGH THE
EVENING. HIGHER GUSTS TO 30 KTS ARE POSSIBLE PARTICULARLY AT KMKG.
SNOW SHOWERS WILL GRADUALLY END AT MOST OF THE TERMINALS OVERNIGHT
WITH MAINLY MVFR CONDITIONS LATE TONIGHT INTO SATURDAY DUE TO
LINGERING LOW CLOUDS. HOWEVER LAKE EFFECT SNOW SHOWERS WILL DEVELOP
OVERNIGHT AND IMPACT KMKG RESULTING IN MAINLY IFR CONDITIONS THERE.
AS LOW LEVEL WINDS BACK FROM THE NORTH TO THE NW SATURDAY MORNING I
EXPECT THAT THE LAKE EFFECT SNOW BAND WILL BEGIN TO PROPOGATE INLAND
AND POTENTIALLY REACH KGRR AND KAZO AND POINTS ALONG THE US-131
CORRIDOR TOWARD MIDDAY SATURDAY.
&&
.MARINE...(346 AM EST FRI FEB 10 2012)
WE/LL SEE AN ABRUPT WIND SHIFT TODAY AS A STRONG COLD FRONT MOVES
THROUGH. WINDS WILL GUST FROM THE NORTH BEHIND THE FRONT TO JUST
UNDER GALE FORCE AND THEN DIMINISH OVERNIGHT. AS TEMPS FALL BELOW
FREEZING LATER THIS AFTERNOON AND TONIGHT...THE GUSTY WINDS MAY
RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THIS AFTERNOON AND EVENING FOR ALL BUT
THE NORTHERN TWO ROWS OF COUNTIES.
LM...GALE WARNING IN EFFECT THROUGH SATURDAY MORNING.
SMALL CRAFT ADVISORY SATURDAY MORNING THROUGH SUNDAY AFTERNOON.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93
LONG TERM: MJS
AVIATION: LAURENS
MARINE: 93
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
645 AM EST FRI FEB 10 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(346 AM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMINISH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(645 AM EST FRI FEB 10 2012)
A BAND OF SNOW WILL DROP SOUTHEAST THROUGH THE TAF SITES LEADING TO
IFR CONDITIONS BEGINNING LATER THIS MORNING AND CONTINUING INTO THE
AFTERNOON. CONDITIONS COULD TEMPORARILY GO TO LIFR THIS AFTERNOON.
WINDS WILL INCREASE LATER THIS AFTERNOON AND EVENING AND GUSTS OVER
25 KNOTS FROM THE NORTH ARE FORECASTED FOR THE TAF SITES. THE
DEEPER MOISTURE PULLS AWAY FOR LATE TONIGHT AND THAT SHOULD SHUT
DOWN MOST OF THE SNOW...BUT MVFR CLOUDS WILL PREVAIL.
&&
.MARINE...(346 AM EST FRI FEB 10 2012)
WE/LL SEE AN ABRUPT WIND SHIFT TODAY AS A STRONG COLD FRONT MOVES
THROUGH. WINDS WILL GUST FROM THE NORTH BEHIND THE FRONT TO JUST
UNDER GALE FORCE AND THEN DIMINISH OVERNIGHT. AS TEMPS FALL BELOW
FREEZING LATER THIS AFTERNOON AND TONIGHT...THE GUSTY WINDS MAY
RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THIS AFTERNOON AND EVENING FOR ALL BUT
THE NORTHERN TWO ROWS OF COUNTIES.
LM...SMALL CRAFT ADVISORY THROUGH SATURDAY.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93
LONG TERM: MJS
AVIATION: MJS
MARINE: 93
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
346 AM EST FRI FEB 10 2012
LATEST UPDATE...ALL BUT AVIATION...
.SYNOPSIS...(346 AM EST FRI FEB 10 2012)
AN ARCTIC COLD FRONT WILL MOVE ACROSS LOWER MICHIGAN TODAY BRINGING
A BURST OF SNOW AND MUCH COLDER TEMPERATURES. DRIVING CONDITIONS
WILL LIKELY BE IMPACTED THIS AFTERNOON. COLDER WEATHER WILL LINGER
THROUGH THE WEEKEND BEFORE TEMPERATURES BEGIN CLIMBING BACK TO 40
MIDWEEK.
&&
.SHORT TERM...(346 AM EST FRI FEB 10 2012)
(TODAY THROUGH SUNDAY)
WE/RE RUNNING WITH A WINTER WX ADVISORY THIS AFTERNOON/EVENING FOR
ALL BUT THE NRN 2 ROWS OF COUNTIES. THIS WILL BE AN IMPACT DRIVEN
EVENT FEATURING 1-3 INCHES OF SNOW ALONG WITH RAPIDLY FALLING TEMPS
THIS AFTERNOON.
OF PARTICULAR CONCERN WILL BE TRAVEL CONDITIONS ALONG THE
INTERSTATES 96/94 AS THE HEAVIEST SNOW WILL COMMENCE IN THOSE
LOCATIONS AROUND MID AFTERNOON...AROUND THE TIME SCHOOLS ARE LETTING
OUT AND PEOPLE BEGIN TO HEAD HOME FROM WORK FOR THE WEEKEND. TEMPS
WILL BE IN THE 30S AHEAD OF THE FRONT. LATEST HRRR INDICATES THAT
SOME LIGHT SNOW MAY BEGIN PRIOR TO FROPA. THIS WILL RESULT IN SOME
MELTING ON ROADWAYS WHICH WILL QUICKLY FREEZE BEHIND THE FRONT.
ADDITIONALLY...MUCH OF THE OMEGA IS JUST BELOW THE DGZ SUGGESTING
THAT FLAKE SIZE WILL BE SMALL. SMALL FLAKES COMBINED WITH A FREEZING
ROAD SFC WILL CREATE ICY CONDITIONS. NORTH WINDS GUSTING TO 25-30
MPH WILL ALSO CREATE STRONG CROSS WINDS ON THE E/W INTERSTATES
FURTHER REDUCING VSBYS. ALL OF THESE FACTORS COMBINED WITH THE
TRANQUIL WX WE/VE SEEN RECENTLY MAY CATCH PEOPLE OFF GUARD AND
RESULT IN NUMEROUS SLIDE OFFS. THUS WE FELT IT PRUDENT TO HIGHLIGHT
THIS EVENT WITH AN ADVISORY.
THE SNOW WILL DIMINISH A FEW HOURS AFTER FROPA. THIS DOES/T LOOK
LIKE A BIG LAKE EFFECT PRODUCER FOR US. BOUNDARY LAYER WINDS BECOME
NNE TONIGHT RESULTING IN A DOMINANT BAND FROM JUST OFF SHORE
LUDINGTON SSW TO NEAR CHICAGO. IT REMAINS POSSIBLE THAT THE MAIN
BAND COULD CLIP THE POINTS AND WE/LL KEEP AN EYE ON THAT.
INLAND...NORTH WINDS SHOULD LEAD TO SOME CLEARING.
WINDS BEGIN TO BACK TO THE NW SATURDAY AS WARM AIR ADVECTION BEGINS.
THIS WILL CAUSE SHSN OVER THE LAKE TO MOVE INLAND. THE LAKESHORE
AREAS SOUTH OF GRAND HAVEN HAVE THE BEST CHANCE AT SEEING UP TO AN
INCH. PCPN WILL DIMININSH SATURDAY NIGHT AND SUNDAY LOOKS DRY AS
TEMPS CLIMB BACK UP TO 30.
&&
.LONG TERM...(346 AM EST FRI FEB 10 2012)
(SUNDAY NIGHT THROUGH THURSDAY)
THE MAIN CHALLENGE IN THE LONG TERM DEALS WITH THE SNOW AMOUNTS FOR
MONDAY INTO TUESDAY.
MODELS ARE TRENDING TOWARD A FASTER AND WEAKER SYSTEM FOR THIS TIME
FRAME. MODELS ARE IN DECENT AGREEMENT IN SHOWING WEAK LIFT BUT
DECENT MOISTURE DEPTH ESPECIALLY MON NIGHT. AT THIS POINT WILL KEEP
POPS UNDER LIKELY AS THE TREND HAS BEEN FOR A WEAKER SYSTEM. THE
DGZ BECOMES UNSATURATED TUESDAY...THUS THE POTENTIAL FOR MEASURABLE
AMOUNTS DROPS OFF.
HIGH PRESSURE MOVES IN FOR WED. THAT WILL LIMIT THE RISK FOR
PRECIPITATION. HOWEVER ANOTHER STORM SYSTEM WILL RIDE UP THE OH
VALLEY ON THU. THIS COULD LEAD SOME SNOW FOR SW LOWER MI.
&&
.AVIATION...(1158 PM EST THU FEB 9 2012)
EXPECT 3 TO 5 HOURS OF LIFR CIGS/VSBY WITH SNOW AT ALL TAF SITES
DURING FROM LATE MORNING INTO EARLY EVENING FRIDAY.
THE LOW CLOUDS (MVFR CIGS STREAMED IN FROM LAKE MICHIGAN EARLIER
THAN EXPECTED SO I UPDATED THE TAFS ALREADY TO ACCOUNT FOR THAT AND
BELIEVE THEY WILL REMAIN ALL NIGHT INTO FRIDAY.
THE NEXT ISSUE IS WILL THERE BE LAKE ENHANCED SOUTHWEST FLOW SNOW
SHOWERS AHEAD OF THE ARCTIC FRONT AT MKG...GRR AND AZO BTW 12Z AND
16Z? THE 950 TO 850 RH IS MARGINALLY HIGH ENOUGH AND THERE IS SOME
LIFT IN THE DGZ TOO. THE HRRR SHOWS THIS ALSO BUT THE RH BECOMES
LOWER AS ONE IS FARTHER SOUTH FROM THE PRIMARY COLD FRONT SO I HAVE
THE SNOW STARTING EARLY AT MKG BUT NOT SO MUCH AT GRR AND AZO. THAT
WILL HAVE TO BE WATCHED.
THE BIGGEST CHANGE IS THAT THE NAM AND GFS ARE MUCH STRONGER ON THE
SURFACE LOW FOR FRIDAY AFTERNOON. THIS CREATES A SIGNIFICANTLY
LONGER PERIOD OF SNOW AND IT THE SNOW WOULD CONTINUE PAST SUNSET AT
LOCATIONS EAST OF GRR. LIFR CONDITIONS WOULD SEEM LIKELY AT MOST TAF
SITES FRIDAY AFTERNOON DUE TO SNOW AND MAYBE EVEN BLOWING SNOW AS
THE COLD AIR BECOMES MORE ENTRENCHED WHILE THE LOW LEVEL WINDS KICK
UP AFTER 21Z. WE WILL HAVE TO MONITOR THIS TOO. CONDITIONS WOULD
NOT IMPROVE MUCH UNTIL AFTER 03Z AT MOST TAF SITES.
&&
.MARINE...(346 AM EST FRI FEB 10 2012)
WE/LL SEE AN ABRUPT WIND SHIFT TODAY AS A STRONG COLD FRONT MOVES
THROUGH. WINDS WILL GUST FROM THE NORTH BEHIND THE FRONT TO JUST
UNDER GALE FORCE AND THEN DIMINISH OVERNIGHT. AS TEMPS FALL BELOW
FREEZING LATER THIS AFTERNOON AND TONIGHT...THE GUSTY WINDS MAY
RESULT IN FREEZING SPRAY.
&&
.HYDROLOGY...(346 AM EST FRI FEB 10 2012)
MINIMAL HYDRO CONCERNS. A COUPLE OF INCHES OF SNOW IS EXPECTED WITH
THE STRONG FRONT TODAY BUT THAT WILL HAVE A LIMITED IMPACT ON AREA
RIVERS. THE ARCTIC AIR THAT OVERSPREADS THE REGION THIS WEEKEND
LIKELY WON/T LAST LONG ENOUGH TO CREATE ICE JAM ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY THIS AFTERNOON AND EVENING FOR ALL BUT
THE NORTHERN TWO ROWS OF COUNTIES.
LM...SMALL CRAFT ADVISORY THROUGH SATURDAY.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93
LONG TERM: MJS
AVIATION: WDM
MARINE: 93
HYDROLOGY: 93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1158 PM EST THU FEB 9 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(320 PM EST THU FEB 9 2012)
AN ARCTIC COLD FRONT WILL SWEEP SOUTH THROUGH LOWER MICHIGAN FRIDAY
AND PRODUCE AN INCH OR TWO OF SNOW. AN ABRUPT DROP IN TEMPERATURES
BEHIND THE FRONT MAY CAUSE HAZARDOUS TRAVEL AS ROADS TURN ICY. THE
FRIDAY EVENING COMMUTE COULD BE A SLOW ONE WITH SOME SLIDE OFFS
POSSIBLE.
WINDS TURN TO THE NORTH BEHIND THE FRONT FRIDAY NIGHT SO LAKE EFFECT
SNOW SHOWERS WILL BE MOSTLY OFFSHORE EXCEPT AROUND LUDINGTON. SOME
LIGHT ACCUMULATIONS ARE POSSIBLE SATURDAY AND SATURDAY NIGHT WEST OF
HIGHWAY 131 AS THE WINDS BECOME NORTHWESTERLY.
&&
.SHORT TERM...(320 PM EST THU FEB 9 2012)
(TONIGHT THROUGH SATURDAY NIGHT)
THE MAIN FOCUS IN THE SHORT TERM IS THE ARCTIC FRONT FOR FRIDAY AND
IT/S POTENTIAL IMPACT.
GUIDANCE CONTINUES TO SUGGEST A QUICK BURST OF ABOUT ONE INCH OF
SNOW ALONG THE ARCTIC BOUNDARY FRIDAY. TWO INCHES IS POSSIBLE IN THE
ERN CWFA AROUND LAN AND JXN. THIS IS NOT A BIG DEAL AT ALL FOR
FEBRUARY IN LWR MI... BUT IT MAY STILL HAVE SIGNIFICANT TRAVEL
IMPACT.
ASSUMING THE ONE INCH OR SO OF SNOW DOES ACCUMULATE WITH THE
FRONT... THE ABRUPT TEMPERATURE FALL BEHIND THE FRONT MAY LEAD TO
RAPID FORMATION OF VERY ICY ROADS AS TEMPS FALL FROM LOW TO MID 30S
DOWN INTO THE 20S AND TEENS.
HAZARDOUS TRAVEL CONDITIONS WITH SLOW DOWNS AND SLIDE OFFS COULD
DEVELOP DUE TO THE ABRUPT WEATHER CHANGE. THIS COMES AFTER A LENGTHY
PERIOD OF NO WINTER WEATHER AND SAFE TRAVEL... AND MAY CATCH SOME
DRIVERS A BIT OFF GUARD.
OF PARTICULAR CONCERN WILL BE THE INTERSTATE 96 CORRIDOR REGION
SOUTHWARD. THIS MORE DENSELY POPULATED REGION WILL LIKELY HAVE
RELATIVELY HIGH TRAVEL VOLUMES WHEN THE POTENTIAL HAZARD DEVELOPS IN
THE AFTERNOON AND EVENING WHICH INCLUDES THE FRIDAY EVENING/WEEK
END DRIVE HOME COMMUTE.
CONFIDENCE IS STILL SOMEWHAT LOW HOWEVER AT THIS TIME REGARDING
AREAL COVERAGE OF SNOW AMOUNTS AND IF THERE WILL EVEN BE ENOUGH TO
CAUSE SIGNIFICANT TRAVEL IMPACTS. BEST CHANCE FOR IMPACT IS FROM GRR
TO THE EAST AND SOUTHEAST.
ONCE THE SYNOPTICALLY INDUCED SNOW ALONG THE SFC FRONT DEPARTS
FRIDAY EVENING... DRY/COLD NORTH FLOW BEHIND THE FRONT RESULTS IN
DRY WEATHER FOR THE BULK OF THE CWFA WITH THE EXCEPTION OF THE
LUDINGTON AREA. THE LOW LEVEL FLOW DOES BACK TO THE NW ON
SATURDAY... WHICH COULD RESULT IN SOME ACCUMULATIONS WEST OF HIGHWAY
131. SOUTH HAVEN NAM BUFKIT HAS A DECENT OMEGA/DGZ CROSS HAIR
SIGNATURE IN THE CLOUD LAYER SATURDAY AND SATURDAY NIGHT... SO THIS
WILL NEED TO BE MONITORED.
&&
.LONG TERM...(320 PM EST THU FEB 9 2012)
(SUNDAY THROUGH THURSDAY)
FAIR WX IS ANTICIPATED SUNDAY WITH PARTLY SUNNY SKIES AND TEMPS
MODERATING SLIGHTLY TO CLOSER TO NORMAL. THERE IS A CHANCE OF LIGHT
WARM AIR ADVECTION SNOW MONDAY AFTERNOON THROUGH MONDAY NIGHT INTO
TUESDAY. DEEP MOISTURE WILL BE IN PLACE BUT FORCING/OMEGAS WILL BE
VERY WEAK SO ANY SNOW ACCUMULATIONS WILL BE VERY LIGHT.
A BRIEF PERIOD OF DRY WX WILL RETURN LATE TUESDAY THROUGH TUESDAY
NIGHT AND WEDNESDAY. BEYOND THAT A CONSENSUS OF LATEST MEDIUM RANGE
GUIDANCE CONTINUES TO SUGGEST THAT A SOUTHERN STREAM SYSTEM WILL
DEVELOP AND POTENTIALLY TRACK ENE TOWARD OUR REGION LATE NEXT WEEK.
THERE IS STILL A CONSIDERABLE AMOUNT OF UNCERTAINTY REGARDING THE
EXACT TRACK/STRENGTH OF THAT SYSTEM THAT FAR OUT IN TIME THOUGH. IT
IS ALSO NOTED THAT THE 12Z ECMWF HAS BACKED OFF ON THIS NOTION.
TEMPS WILL AVERAGE NEAR NORMAL SUNDAY AND MONDAY BEFORE MODERATING
TO AROUND FIVE TO FIFTEEN DEGREES ABOVE NORMAL TUESDAY THROUGH
THURSDAY.
&&
.AVIATION...(1158 PM EST THU FEB 9 2012)
EXPECT 3 TO 5 HOURS OF LIFR CIGS/VSBY WITH SNOW AT ALL TAF SITES
DURING FROM LATE MORNING INTO EARLY EVENING FRIDAY.
THE LOW CLOUDS (MVFR CIGS STREAMED IN FROM LAKE MICHIGAN EARLIER
THAN EXPECTED SO I UPDATED THE TAFS ALREADY TO ACCOUNT FOR THAT AND
BELIEVE THEY WILL REMAIN ALL NIGHT INTO FRIDAY.
THE NEXT ISSUE IS WILL THERE BE LAKE ENHANCED SOUTHWEST FLOW SNOW
SHOWERS AHEAD OF THE ARCTIC FRONT AT MKG...GRR AND AZO BTW 12Z AND
16Z? THE 950 TO 850 RH IS MARGINALLY HIGH ENOUGH AND THERE IS SOME
LIFT IN THE DGZ TOO. THE HRRR SHOWS THIS ALSO BUT THE RH BECOMES
LOWER AS ONE IS FARTHER SOUTH FROM THE PRIMARY COLD FRONT SO I HAVE
THE SNOW STARTING EARLY AT MKG BUT NOT SO MUCH AT GRR AND AZO. THAT
WILL HAVE TO BE WATCHED.
THE BIGGEST CHANGE IS THAT THE NAM AND GFS ARE MUCH STRONGER ON THE
SURFACE LOW FOR FRIDAY AFTERNOON. THIS CREATES A SIGNIFICANTLY
LONGER PERIOD OF SNOW AND IT THE SNOW WOULD CONTINUE PAST SUNSET AT
LOCATIONS EAST OF GRR. LIFR CONDITIONS WOULD SEEM LIKELY AT MOST TAF
SITES FRIDAY AFTERNOON DUE TO SNOW AND MAYBE EVEN BLOWING SNOW AS
THE COLD AIR BECOMES MORE ENTRENCHED WHILE THE LOW LEVEL WINDS KICK
UP AFTER 21Z. WE WILL HAVE TO MONITOR THIS TOO. CONDITIONS WOULD
NOT IMPROVE MUCH UNTIL AFTER 03Z AT MOST TAF SITES.
&&
.MARINE...(320 PM EST THU FEB 9 2012)
BRISK SOUTHWEST TO WEST FLOW WILL SHIFT NORTH BEHIND THE ARCTIC
FRONT ON FRIDAY. BRISK NORTHWEST WINDS CONTINUING FOR SATURDAY AND
SUNDAY AS CYCLONIC FLOW AND COLD AIR IMPACTS THE REGION.
WINDS AND WAVE WILL REMAIN HAZARDOUS TO SMALL CRAFT THROUGH THE
WEEKEND. FREEZING SPRAY COULD BE AN ISSUE AS WELL FOR FRIDAY NIGHT
AND BEYOND... AND MAY REQUIRE AN ADVISORY FOR ICE ACCRETION.
&&
.HYDROLOGY...(320 PM EST THU FEB 9 2012)
AREA RIVERS CONTINUE TO SLOWLY FALL. LIMITED QPF THROUGH THE WEEKEND
WILL RESULT IN THE SLOW FALL CONTINUING. ICE FORMATION ON THE RIVERS
AND THE POTENTIAL FOR ICE JAMS SHOULD INCREASE OVER THE WEEKEND
AS THIS BRIEF BOUT OF ARCTIC AIR IMPACTS THE REGION.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY THROUGH SATURDAY.
&&
$$
SYNOPSIS: MEADE
SHORT TERM: MEADE
LONG TERM: LAURENS
AVIATION: WDM
MARINE: MEADE
HYDROLOGY: MEADE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1143 PM CST THU FEB 9 2012
.AVIATION... /06Z TAF ISSUANCE/
A COLD FRONT WILL MOVE THROUGH KEAU BETWEEN 06Z-07Z. BRISK
NORTHWEST WINDS AT 15 TO 20 KNOTS WILL CONTINUE AT THE TAF SITES
IN THE WAKE OF THE FRONT...THEN SLOWLY DIMINISH ON FRIDAY. SOME
LIGHT SNOW SHOWERS MAY BRUSH KEAU OVERNIGHT WITH TEMPORARY MVFR
VISIBILITY. CLOUD TRENDS ARE ANOTHER CONCERN. IT IS BECOMING
APPARENT THAT THE LOW LEVEL MOISTURE IS WAY OVERDONE ON THE NAM
WITH VFR CEILINGS FROM CENTRAL MN NORTHWARD. SO...KMSP...KRNH AND
KEAU MAY ONLY SEE A FEW HOURS OF MVFR EARLY THIS MORNING.
HOWEVER...AS THE LOW LEVEL FLOW TURNS NORTHEAST...THE FLOW WILL BE
COMING OFF LAKE SUPERIOR BY FRIDAY MORNING AND THIS MAY BRING
ANOTHER ROUND OF MVFR CEILINGS TO THE AFOREMENTIONED SITES.
CONFIDENCE IS HIGH ON THE LOW CLOUDINESS BUT NOT ON WHETHER OR NOT
THE CEILINGS WILL BE MVFR.
KMSP...NORTHWEST WINDS AT 15 TO 20 KNOTS OVERNIGHT WITH GUSTS
FROM 25 TO 30 KNOTS. CONFIDENCE IS NOT HIGH THAT MVFR CEILINGS
WILL PERSIST THROUGH FRIDAY MORNING. IT MAY BE BROKEN INTO TWO
WAVES...ONE NOW THROUGH 10Z WITH ANOTHER 14Z-18Z ON FRIDAY. USED
BKN035 FOR FRIDAY MORNING.
&&
.DISCUSSION... /ISSUED 241 PM CST THU FEB 9 2012/
ARCTIC COLD FRONT WITH DECENT PRESSURE FALLS OVER NORTH DAKOTA DROPPING
SOUTH ABOUT AS FORECAST. NOT TOO MANY SITES REPORTING SNOW BUT
A COUPLE OF SITES IN NW ONT WERE DOWN TO AROUND 2SM. THE LATEST RUC
AND THE NAM TO A LESSER EXTENT DO FORECAST AN INCREASE IN QG VERT
VEL AND FGEN TO OUR NE AS THE FRONT DROPS SOUTH WILL INCREASE POPS
TO A CHANCE CATEGORY OVER IN WEST CENTRAL WI TO ACCOUNT FOR THIS.
WITH THE FRONT MOVING DOWN WILL GO WITH A MODEL WEIGHTED DIURNAL
TEMP TREND OVERNIGHT. SOME GUSTY WINDS FOR A TIME WITH THE COLD
ADVECTION TOO. NOT MUCH TEMP CHANGE FROM THE MORNING IN THE SE
FOR FRIDAY HIGHS.
FEEL THAT THE NAM IS OVERDOING THE LOW LEVEL MOISTURE FIELDS ON
FRIDAY WITH THE GFS AND RUC LOOKING BETTER AT LEAST IN THE MN
PORTION OF THE AREA. COLD ADVECTION OS THERE...BUT WE LOOSE THE
CYCLONIC CURVATURE IN THE AFTERNOON. LOOKS LIKE A COLD LOOKS
COLD FRIDAY NIGHT UNDER CLEAR SKIES BUT WITH A PRES GRADIENT
CONTINUING. MOST SITES LIKELY BELOW ZERO BUT THIS REGIME IS NOT
AS COLD AS THE MID JANUARY BLAST.
MODERATION BEGINS LATE IN THE WEEKEND AND EARLY NEXT WEEK WITH A
RETURN TO A MORE WESTERLY FLOW BUT SOMEWHAT SPLIT WITH MORE
BLOCKING AROUND THE NORTHERN HEMISPHERE. WE STILL HAVE A CHANCE OF
SNOW FOR SOUTHERN AREAS MONDAY AND MONDAY NIGHT WITH A CENTRAL
PLAINS TROUGH. PRECIP PROBS BETTER IN THE CENTRAL PLAINS THOUGH.
THERE HAD BEEN SOME CHANCE AGAIN LATER WEDNESDAY AND THURSDAY BUT
THE 12Z ECMWF...AND GFS ENSEMBLE POPS ARE NOT SHOWING MUCH. THE
12Z GFS IS THE ONLY MODEL TO SHOW SOME A CHANCE BUT THIS A LITTLE
CLOSE BEHIND THE MONDAY SYSTEM IN A SPLIT FLOW. TEMPS BACK TO NEAR
OR ABOVE NORMAL NEXT WEEK.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/JPR
AREA FORECAST DISCUSSION
NWS BILLINGS MT
249 PM MST FRI FEB 10 2012
.SHORT TERM...VALID FOR SAT AND SUN...
SNOW CONTINUES THIS AFTERNOON IN OUR WEST NEAR LIVINGSTON AND BIG
TIMBER AND ALONG THE BEARTOOTH ABSAROKA FOOTHILLS. IMPRESSIVE DRY
SURGE HAS CLEARED OUT SKIES EAST OF A HYSHAM TO BROADUS LINE...AND
IN THIS AREA SFC DEWPTS ARE IN THE SINGLE DIGITS BELOW ZERO. MOIST
ISENTROPIC ASCENT WILL CONTINUE TO BRING SNOWFALL TO OUR FAR WEST
TONIGHT...WITH ENHANCEMENT IN UPSLOPE AREAS ALONG THE BEARTOOTH
FOOTHILLS. THIS ASCENT ALONG WITH NORTH WINDS SHOULD ALSO BRING
ADDITIONAL ACCUMULATION TO THE PARADISE VALLEY THROUGH TONIGHT.
HAVE OPTED TO ADD THE RED LODGE FOOTHILLS TO THE ADVISORY...LESS
FOR THE CITY OF RED LODGE ITSELF WHICH IS A BIT SHELTERED IN THIS
EVENT AND MORE FOR THE WESTERN PART OF THIS ZONE NEAR ROSCOE AND
LUTHER...WHERE WEB CAMERAS AND RADAR SHOW PCPN HAS BEEN A BIT
HEAVIER. OVERALL TOTALS OF 3 TO 6 INCHES SHOULD SUFFICE FOR ALL OF
THESE AREAS THROUGH 6AM SATURDAY.
AS FOR THE CITY OF BILLINGS...WE ARE CAUGHT BETWEEN THE MOIST
ASCENT TO OUR WEST AND DRY AIR TO OUR EAST. WITH LOW LEVEL UPSLOPE
AND DENDRITIC LAYER IN PLACE WE WILL LIKELY SEE PERIODS OF VERY
LIGHT SNOW OR FLURRIES TONIGHT...BUT WITH LITTLE IF ANY ADDITIONAL
ACCUMULATION AS THE MOISTURE WILL BE SHALLOW. WE MAY EVEN DRY OUT
COMPLETELY LATE TONIGHT AS THE LATEST RUC IS SUGGESTING. WE MISSED
OUT ON A MORE SIGNIFICANT SNOW EVENT IN THE CITY OF BILLINGS BY 50
TO 100 MILES.
ONSET OF WEAK MID LEVEL WARM ADVECTION COMBINED WITH THE LOW LEVEL
UPSLOPE AND DENDRITIC LAYER WILL ALLOW FOR LIGHT SNOW OR FLURRIES
TO CONTINUE ACROSS OUR WEST HALF TOMORROW AND TOMORROW NIGHT. THIS
INCLUDES THE CITY OF BILLINGS WHICH SHOULD SEE MOISTURE DEEPEN A
BIT OVER TIME ON SATURDAY. ACCUMULATIONS WILL BE MEAGER AT LESS
THAN AN INCH DURING THIS TIME PERIOD.
WEAK TROFFING AND CYCLONIC FLOW WILL KEEP THE THREAT OF FLURRIES
GOING ON SUNDAY...BUT WITH A TRANSITION TO WEAK LOW LEVEL
DOWNSLOPE FLOW AND WARMER TEMPS.
EXPECT THE COLDEST NIGHT IN AWHILE TONIGHT WITH SINGLE DIGITS AT
BILLINGS AND BELOW ZERO IN THE DRY AIR TO OUR EAST. COLD AIRMASS
WILL REMAIN IN PLACE PER LEE SIDE SFC RIDGING AND EAST WINDS ON
SATURDAY...WITH HIGHS MOSTLY IN THE 20S...THOUGH WITHOUT SNOW
COVER OUR EAST WILL SEE A FAIR DIURNAL RISE DURING THE DAY.
AIRMASS WILL MODERATE FURTHER ON SUNDAY THOUGH DOWNSLOPE FLOW WILL
BE FAIRLY WEAK SO WARM UP WILL NOT BE DRAMATIC...ESPECIALLY WITH
SOME SNOW COVER TO DEAL WITH IN OUR WEST. SHOULD SEE HIGHS INTO
THE 30S ON SUNDAY...IE CLOSER TO MID FEBRUARY NORMALS.
JKL
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
RELATIVELY MINOR CHANGES ONCE AGAIN TO THE EXTENDED PERIOD...AS
MODELS CONTINUE TO DIVERGE AFTER TUESDAY.
RIDGING ALOFT SHOULD ALLOW TEMPS TO RISE BACK TO AROUND 40 IN MOST
AREAS ON MONDAY...WITH RELATIVELY LIGHT SNOW COVER REMAINING.
WOULD NOT EXPECT TO SEE MUCH IN THE AWAY OF POPS OUTSIDE THE
MOUNTAINS...BUT INHERITED POPS INCREASING IN THE MOUNTAINS THROUGH
MONDAY LOOKS GOOD WITH INCREASING MOISTURE AVAILABILITY.
THE TROF PROGGED FOR TUESDAY STILL LOOKS TO BE ON TRACK...BUT ALSO
CONTINUES TO BE UNIMPRESSIVE WITH MINIMAL DYNAMIC SUPPORT. CANNOT
RULE OUT SLIGHT POPS INTO PLAINS TUESDAY AFTERNOON/EVENING. LOOKS
LIKE CLOUD COVER AND PUSH OF COOL AIR SHOULD BE ENOUGH TO LIMIT
HIGH TEMPS TO MID 30S IN MOST AREAS.
PATTERN GENERALLY CONTINUES WITH RIDGING AND MOISTURE INFLUX FOR
WEDNESDAY...BUT AT THIS POINT MODELS ARE DIVERGING AGAIN. GFS
DROPS ANOTHER TROF THROUGH THE REGION...IMPACTING MAINLY THE
WESTERN AND CENTRAL ZONES...WHILE EC MAINTAINS NORTHERLY FLOW IN
ADVANCE OF RIDGE. THE MODELS THEN SEEM TO SUPPORT RIDGING THROUGH THE
END OF THE EXTENDED...WITH GFS BRINGING STRONG PACIFIC TROF IN
FOLLOWING THE END OF THE FORECAST PERIOD. HAVE CONTINUED WITH
MAINLY CLIMO TYPE TEMPS THROUGH THIS PERIOD...AS AM SEEING
NOTHING TO POINT SIGNIFICANTLY HIGHER OR LOWER. AAG
&&
.AVIATION...
MVFR FLIGHT CONDITIONS PREVAIL ACROSS SOUTH CENTRAL MONTANA...UNDER
LOW CIGS. LOCALIZED IFR CONDITIONS CONTINUE IN HEAVIER SNOW
SHOWERS DUE TO REDUCED VIS...ESPECIALLY WEST AND SOUTH OF
KBIL...INCLUDING KLVM AND K6SO. AREAS FURTHER EAST AND
NORTHEAST...INCLUDING KMLS AND KBHK...WILL REMAIN CLEAR. SNOW IS
EXPECTED TO CONTINUE THROUGH THE NIGHT AND INTO SATURDAY...BUT
WITH LITTLE ACCUMULATION OTHER THAN IN HEAVIER BAND WEST OF KBIL.
MOUNTAINS WILL BE OBSCURED THROUGH THE REMAINDER OF THE EVENING
AND OVERNIGHT. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 006/023 014/036 021/042 023/036 023/038 023/038 023/042
86/S 31/M 11/B 12/J 21/B 11/B 22/J
LVM 013/028 018/038 022/040 018/035 020/036 017/036 018/040
+7/S 41/M 11/B 12/J 21/B 11/B 22/J
HDN 006/027 011/035 020/042 021/037 021/039 020/039 021/043
43/S 21/M 11/B 12/J 21/B 11/B 22/J
MLS 905/027 006/033 019/041 022/036 021/038 021/038 022/042
00/U 00/B 11/B 12/J 21/B 11/B 11/B
4BQ 903/028 009/032 019/042 022/037 021/038 021/038 021/042
01/U 01/B 11/B 12/J 21/B 10/B 11/B
BHK 909/025 001/030 017/039 019/035 019/035 018/035 017/039
00/U 00/U 01/U 12/J 21/B 10/B 11/B
SHR 009/028 012/036 020/042 018/035 019/036 016/036 017/040
74/S 21/M 11/B 12/J 21/B 11/B 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST SATURDAY FOR
ZONES 34-41-56-64>66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
349 PM EST FRI FEB 10 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTH THIS EVENING...THEN DROP
ACROSS THE REGION LATE TONIGHT. SCATTERED SNOW SHOWERS THROUGH THIS
EVENING WILL BECOME MORE WIDESPREAD LATE TONIGHT INTO SATURDAY. THIS
WILL BRING IN COLDER TEMPERATURES AND SOME SNOW ACCUMULATION.
ANOTHER COLD FRONT WILL APPROACH FROM THE NORTH...WHICH WILL LIKELY
BRING A ROUND OF LAKE SNOWS LATE SATURDAY NIGHT INTO SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
OUR WEATHER WILL CONTINUE TO KEY ON THE PROGRESSION OF AN
APPROACHING FRONTAL BOUNDARY. OUTSIDE OF SOME LAKE EFFECT EAST OF
LAKE ONTARIO...EXPECT GENERALLY LIGHT AND PATCHY SNOW ACCUMULATION
AHEAD OF THE FRONT.
THE 12Z MODEL RUNS CONTINUE TO SLOW THE PROGRESSION OF THE COLD
FRONT. THE UPPER LEVEL TROF DRIVING THE FRONT IS FORECAST TO
SHARPEN...WHICH EFFECTIVELY SLOWS THE PROGRESSION OF THE FRONT...AND
ALSO AIDS IN THE DEVELOPMENT OF A WEAK SURFACE LOW ALONG THE
BOUNDARY. THE 12Z NAM/GFS/RGEM ARE ALL SUPPORTING THIS SLOWER
PROGRESSION...WHICH HAS BEEN THE TREND FOR SEVERAL RUNS NOW.
THIS WILL HAVE A FAIRLY SIGNIFICANT IMPACT ON THE FORECAST...SINCE
THE SLOWER PROGRESSION OF THE FRONT WILL PUSH BACK START TIME OF THE
STEADY SNOW UNTIL LATE TONIGHT. ACROSS NORTHWESTERN NEW YORK FROM
BUFFALO-ROCHESTER NORTHWARD...EXPECT THE STEADIEST SNOW FROM 600 AM
THROUGH NOON...SLIGHTLY LATER TO THE SOUTH OF THIS.
GENERALLY ACCEPT THE CONSENSUS QPF FROM THE 12Z NAM12/RGEM...THOUGH
SOME UPSLOPE ENHANCEMENT MAY OCCUR BEYOND MODEL QPF FORECASTS. THERE
SHOULD BE A PERIOD OF SNOW BOTH ALONG THE FRONT...AND BEHIND THE
FRONT DUE TO LAKE ENHANCEMENT AND UPSLOPING.
EXPECT THE MOST SNOW TO FALL ACROSS WESTERN PORTIONS OF THE SOUTHERN
TIER...WHERE THE SURFACE LOW...UPPER LEVEL TROF...AND UPSLOPING
SHOULD ALL COME TOGETHER TO BRING SEVERAL HOURS OF MODERATE SNOWS.
EXPECTING 3 TO 5 INCHES IN THE FAVORABLE UPSLOPE RIDGES...AND BASED
ON THIS WILL ISSUE A WINTER WEATHER ADVISORY FOR
CHAUTAUQUA/CATTARAUGUS COUNTIES. SNOW AMOUNTS WILL BE LESS
ELSEWHERE...THOUGH GENERALLY EXPECT 2 OR 3 INCHES IN BUFFALO
METRO/BOSTON HILLS/NIAGARA FRONTIER. AMOUNTS TO THE EAST SHOULD BE
LESS...FURTHER FROM THE UPPER TROF...WITH GENERALLY 2 INCHES OR LESS
EXPECTED.
THE EAST TO WEST ORIENTATION OF THE FRONT WILL ALLOW IT TO DROP
ACROSS THE NORTH COUNTRY EARLIER...WITH THE FRONT LIKELY TO SLOWLY
DROP ACROSS SHORTLY AFTER MIDNIGHT. WHILE THIS REGION IS FURTHER
REMOVED FROM THE UPPER LOW AND THE DEEPER MOISTURE...THERE WILL BE A
PERIOD FAVORABLE FOR LAKE ENHANCEMENT IMMEDIATELY AHEAD OF THE
FRONT. RADAR TRENDS AND THE HRRR SUPPORT DEVELOPMENT OF FAIRLY
WIDESPREAD LAKE ENHANCED SNOW SHOWERS AHEAD OF THE FRONT...DESPITE
MINIMAL QPF FROM THE NAM/RGEM. HERE...MOST OF THE SNOW SHOULD FALL
LATE AFTERNOON AND THIS EVENING...AHEAD OF THE FRONT...WHERE 1 TO 3
INCHES IS POSSIBLE ON THE TUG HILL AND IN JEFFERSON COUNTY.
THE SLOWER PROGRESSION OF THE FRONT WILL ALSO HAVE A BIG IMPACT ON
TEMPERATURES. WHILE THE FRONT WILL STILL PASS THROUGH THE NORTH
COUNTRY...IT IS QUESTIONABLE IF THE COLD AIR WILL MAKE IT INTO
BUFFALO BY DAYBREAK. THE RESULT IS LOW TEMPERATURES WHICH ARE QUITE
A BIT WARMER ALONG THE I-90 CORRIDOR. THIS SAID...THE FRONT WILL
STILL CROSS...AND TEMPERATURES WILL DROP BEHIND THE FRONT SATURDAY
MORNING. SATURDAY WILL STILL BE A COLD DAY...WITH MID-DAY
TEMPERATURES IN THE UPPER TEENS TO LOWER 20S...EVEN IF THE MORNING
STARTS OFF A BIT WARMER THAN THIS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AN ACTIVE PERIOD SATURDAY NIGHT AND INTO SUNDAY AS LAKE EFFECT SNOW
IS EXPECTED...ENHANCED BY A SOUTHWARD DROPPING ARCTIC FRONT SUNDAY.
SATURDAY NIGHT THE AXIS OF AN UPPER LEVEL TROUGH WILL BE CROSSING
THE REGION...WITH WINDS THROUGH THE BOUNDARY LAYER EXHIBITING TOO
MUCH SHEER...AND LIMITED BOUNDARY LAYER MOISTURE FOR ANY LAKE EFFECT
TO BE ONGOING. SYNOPTIC SNOW WILL BE ENDING ACROSS THE SOUTHERN TIER
EARLY SATURDAY NIGHT WITH LITTLE FURTHER SNOW ACCUMULATION.
TEMPERATURES ALOFT AT 850 HPA WILL BE PLENTY COLD ENOUGH TO SUPPORT
LAKE EFFECT SNOW THOUGH LIFT REMAINS MARGINAL AND MOISTURE IN THE
GOOD SNOW CRYSTAL GROWTH ZONE REMAINS LIMITED TO START.
AS THE NIGHT PROGRESS MOISTURE IN THE LOWER LEVELS INCREASES AND
LAKE INDUCED EQUILIBRIUM LEVELS INCREASE ALONG WITH A DECREASE IN
WIND SHEAR. THIS WILL FAVOR THE FORMATION OF LAKE EFFECT SNOW
BANDS...WITH AN UPSTREAM CONNECTION TO LAKE HURON AND GEORGIAN BAY
LIKELY. THE GREATEST LIFT WILL BE CENTERED OVER LAKE ONTARIO AND
INLAND TOWARDS THE GENESEE VALLEY AND WITH AN UPSTREAM CONNECTION TO
GEORGIAN BAY HERE IS WHERE THE HEAVIEST SNOW BAND IS EXPECTED.
WITH THE UPPER LEVEL WINDS A LITTLE MORE BACKED IN THE LONG WAVE
TROUGH THE FOCUS OF THE LAKE EFFECT SNOW SATURDAY NIGHT IS EXPECTED
TO BE CENTERED MORE FROM SOUTHERN SHORELINE OF LAKE ONTARIO AND
INLAND ACROSS THE NORTHERN GENESEE VALLEY AND TOWARDS THE WESTERN
FINGER LAKES REGION...AND BECOMING LESS LIKELY TOWARDS THE EASTERN
END OF LAKE ONTARIO.
NORTHWEST FLOW ACROSS LAKE ERIE WILL BE PERPENDICULAR...AND LOW
LEVEL LIFT AND CONVERGENCE IS NOT AS GREAT. SNOW OF LAKE ERIE WILL
BE FOCUSED UPON AREAS SOUTH OF BUFFALO...ACROSS SKI COUNTRY AND THE
SOUTHERN TIER.
TOWARDS SATURDAY NIGHT AN ARCTIC FRONT WILL BE DROPPING SOUTHWARD
ACROSS OUR REGION FROM SOUTHERN CANADA. BY 12Z SUNDAY EXPECT THIS
FRONT TO BE PUSHING TOWARDS THE SOUTHERN SHORELINE OF LAKE ONTARIO.
BEHIND THIS FRONT SFC TEMPERATURES WILL DROP INTO THE SINGLE DIGITS
AND LOWER...AND WITH WINDS LIKELY IN THE 5 TO 10 KNOTS RANGE WIND
CHILLS WILL FALL TO -20F OR LOWER SUNDAY MORNING ACROSS PORTIONS OF
THE NORTH COUNTRY. WILL MENTION THESE WIND CHILL TEMPERATURES IN THE
HWO...WITH FURTHER SHIFTS MONITORING FOR ANY WIND CHILL ADVISORIES.
AS THIS ARCTIC FRONT DROPS SOUTHWARD EXPECT THE BAND OF LAKE EFFECT
SNOW OFF LAKE ONTARIO TO BECOME ENHANCED. INCREASING WIND SPEEDS AND
COLD TEMPERATURES WILL CREATE BLUSTERY AND BLOWING SNOW CONDITIONS
EARLY SUNDAY MORNING...AND AS THE FRONT DROPS SOUTHWARD EXPECT THIS
BOUNDARY TO TAKE THE LAKE EFFECT SNOWBAND AND PUSH IT SOUTHWARD WELL
INLAND ACROSS SOUTH OF LAKE ONTARIO. THIS MAY CREATE A SEVERAL HOUR
PERIOD OF REDUCED VISIBILITIES WITHIN THE BLOWING AND FALLING SNOW.
LAKE EFFECT SNOW/SNOW ALONG THE ARCTIC FRONT WILL CONTINUE THROUGH
THE DAY SUNDAY WITH THE FOCUS ALONG THE ARCTIC FRONT. WIND SHEER MAY
DISRUPT THE BANDS THROUGH THE DAY SUNDAY TO HOLD SIGNIFICANT
ACCUMULATIONS FROM OCCURRING AT ANY GIVEN LOCATION. WAA STARTS LATER
IN THE DAY SUNDAY...BUT WITH THE DEEP COLD AIRMASS TEMPERATURES
SUNDAY WILL REMAIN COLD ENOUGH TO SUPPORT LAKE EFFECT
ACTIVITY...WHILE AFTERNOON HIGHS REMAIN BELOW NORMAL.
HIGH PRESSURE FOLLOWING THE ARCTIC FRONT WILL BUILD ACROSS THE NORTH
COUNTRY SUNDAY AND WILL JUST HAVE CHC POPS EARLY SUNDAY ACROSS THE
NORTH COUNTRY...WHILE SOUTHWARD WILL HAVE LIKELY TO CATEGORICAL
POPS.
LAKE EFFECT SNOW WILL DIMINISH SUNDAY NIGHT AND AS THE WINDS
BACK...LIFT NORTHWARD TOWARDS THE EASTERN LAKE ONTARIO REGION
MONDAY. AS THE UPPER LEVEL RIDGE BUILDS ACROSS THE REGION MONDAY
EXPECT SKIES TO CLEAR...WITH TEMPERATURES RISING BACK TO THE
FREEZING MARK...AND NEAR NORMAL.
CLOUDS WILL INCREASE THROUGH THE NIGHT MONDAY NIGHT AS THE NEXT
SYSTEM FROM THE WEST NEARS THE REGION WITH LIGHT SNOW RETURNING LATE
TO WNY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
SEVERAL UPPER LEVEL SHORT WAVES THROUGH A SPLIT FLOW THIS TIME
PERIOD WILL CREATE AN ACTIVE TIME PERIOD FOR THE LONG RANGE...THOUGH
EACH SINGLE SYSTEM AT PRESENT MOMENT DOES NOT APPEAR SIGNIFICANT.
WITH A RETURN TO A MORE ZONAL FLOW THIS PERIOD TEMPERATURES WILL
AVERAGE AROUND NORMAL...WITH ANY GREAT DEPARTURES FROM NORMAL COMING
ON ANY PHASING OF THE NORTHERN AND SOUTHERN SHORTWAVES...THEREBY
AMPLIFYING THE FLOW SOME.
TUESDAY THE GFS/ECMWF/GGEM BRING A WEAK SHORT WAVE EJECTING FROM THE
SOUTHWEST ACROSS THE EASTERN GREAT LAKES. TEMPERATURES ALOFT ON BOTH
THE GFS/ECMWF RANGE FROM -6 TO -8C AND WITH THE 06Z GEFS MEMBERS
SUPPORTING ALL SNOW WILL KEEP THE P-TYPE AS SNOW FOR VALENTINES DAY.
FOR NOW WILL LEAVE AS HIGH CHANCE POPS...AS QPF IS ON THE LIGHT SIDE
AND THE SHORT WAVE IS EXPECTED TO FLATTEN OUT AS IT NEARS THE NORTH
EAST. TEMPERATURES TUESDAY UNDER A CLOUDY SKY WILL NOT STRAY MUCH
FROM NORMAL.
WILL HAVE SNOW TAPERING OFF TUESDAY NIGHT WITH THE FLATTENING
SHORTWAVE PASSING BY.
TIMING AND STRENGTH OF THE NEXT SHORT WAVE...THIS TIME IN THE
NORTHERN BRANCH OF THE JET STREAM REMAINS UNCERTAIN. BOTH THE 12Z
GFS AND 12Z ECMWF HAVE BOTH BEEN HINTING AT A SHORT WAVE
CROSSING...THOUGH TIMING AND STRENGTH HAVE BEEN FLUCTUATING. WILL
CONTINUE WITH LOW CHC POPS FOR WEDNESDAY.
BOTH THE GFS AND ECMWF HAVE A SFC HIGH PRESSURE ACROSS THE REGION
WEDNESDAY NIGHT AND INTO THURSDAY MORNING AND THIS FEATURE WILL
ALLOW FOR DIMINISHING POP CHCS THOUGH WITH LOW LEVEL MOISTURE
REMAINING...AND POSSIBLY TRAPPED BELOW AN INVERSION WILL MAINTAIN
MOSTLY CLOUDY SKY CONDITIONS.
BOTH THE OPERATIONAL RUNS OF THE GFS AND ECMWF BRING ANOTHER
SHORTWAVE ACROSS THE EASTERN GREAT LAKES LATER THURSDAY AND
INTO FRIDAY ALONG WITH AN INCREASE IN MOISTURE. WILL BRING CHC POPS
BACK TO THE REGION LATE THURSDAY TO THE SOUTHERN TIER...AND THROUGH
THE NIGHT THURSDAY AND INTO FRIDAY.
PRECIPITATION TYPE WEDNESDAY THROUGH FRIDAY IS CHALLENGING AS 850S
RISE TO NEAR -4C ON THE GFS WEDNESDAY...THOUGH THE ECMWF MAINTAINS A
DEEPER COOL POOL OVER THE EASTERN GREAT LAKES. WILL HAVE BOTH RAIN
AND SNOW MENTIONED IN THE GRIDS FOR WEDNESDAY...
A MILDER RETURN FLOW BEHIND THE DEPARTING SFC HIGH THURSDAY AND
FRIDAY WILL ALSO ALLOW FOR PRECIPITATION TO COME AS A MIX OF RAIN AND
SNOW FOR LATER THURSDAY AND FRIDAY ACROSS THE REGION.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
FROM 21Z TODAY THROUGH 09Z SATURDAY...EXPECT A MIX OF VFR/MVFR
CONDITIONS IN MARGINAL CIGS AND VSBY IN AREAS OF LIGHT SNOW AND
FLURRIES. ONE AREA TO WATCH IS ART...WHERE A BIT MORE INTENSE LAKE
EFFECT BAND MAY DEVELOP...WITH A PERIOD OF IFR CONDITIONS LIKELY
THIS EVENING.
CONDITIONS WILL LOWER SIGNIFICANTLY AT MOST SITES SATURDAY
MORNING...AS A FRONTAL BOUNDARY DROPS ACROSS THE REGION. THIS
FRONTAL PASSAGE WILL KEY A MORE INTENSE PERIOD OF SNOW...WITH IFR
OR LOWER CONDITIONS LIKELY TOWARD DAYBREAK SATURDAY INTO SATURDAY
MORNING.
OUTLOOK...
SATURDAY NIGHT AND SUNDAY...PERIODS OF IFR OR LOWER IN LAKE EFFECT SNOW
SHOWERS.
MONDAY...MAINLY VFR.
TUESDAY AND WEDNESDAY...VFR/MVFR IN CHC OF SNOW.
&&
.MARINE...
WINDS HAVE LARGELY DIMINISHED ACROSS THE WATERS...WITH THE EXCEPTION
OF LAKE ERIE WHERE A SW FLOW SUPPORTS SMALL CRAFT HEADLINES INTO
THIS EVENING. AFTER THIS...THE KEY WILL BE A STRONG COLD
FRONT...WHICH WILL BRING A DECENT NORTHERLY FLOW IN ITS WAKE. FOR
NOW...WILL ISSUE THE SMALL CRAFT ADVISORY FOR THE SOUTH SHORES OF
LAKE ONTARIO. THIS WILL LIKELY HAVE TO BE EXTENDED TO LAKE
ERIE...BUT WILL LET FUTURE SHIFTS DO THIS AS HEADLINES ARE ALREADY
IN PLACE FOR ONGOING CONDITIONS.
WINDS SHOULD DIMINISH SATURDAY NIGHT...BUT ANOTHER FRONTAL BOUNDARY
WILL CAUSE WINDS TO INCREASE AGAIN ON SUNDAY AND SUNDAY NIGHT.
EXPECT SOLID SMALL CRAFT WINDS...WITH THE POSSIBILITY OF GALES
DURING THIS PERIOD. HIGH PRESSURE WILL BUILD TOWARD THE WATERS EARLY
NEXT WEEK.
ONE CONCERN IS THE POTENTIAL FOR FREEZING SPRAY ON SATURDAY NIGHT
INTO SUNDAY...AS TEMPERATURES DROP AND WINDS INCREASE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 4 AM TO 5 PM EST SATURDAY FOR
NYZ019-020.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EST THIS EVENING FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 5 AM EST
SUNDAY FOR LOZ042>044.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...APFFEL
MARINE...APFFEL/RSH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
110 PM EST FRI FEB 10 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM MOVES ACROSS THE MID ATLANTIC AND CAROLINAS
OVERNIGHT...STRENGTHENING OVER THE ATLANTIC SATURDAY. A STRONG COLD
FRONT SWEEPS THROUGH THE REGION IN THE WAKE OF THE LOW SATURDAY.
COLD HIGH PRESSURE BUILDS IN BEHIND THE FRONT FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 1000 AM FRIDAY...
OVERVIEW:
SHORTWAVE ENERGY OVER MISSISSIPPI AND ALABAMA THIS MORNING WILL MOVE
ACROSS THE STATE THIS AFTERNOON AND THIS EVENING. FURTHER
UPSTREAM...A POTENT UPPER LEVEL TROUGH WILL DIG SOUTHEAST INTO THE
UPPER MIDWEST/UPPER GREAT LAKES...PROGRESSING INTO THE OHIO VALLEY
TONIGHT AND APPROACHING THE MID-ATLANTIC BY 12Z SAT. LOW-LEVEL FLOW
WILL BACK TO THE SOUTHWEST TODAY IN ADVANCE OF A SFC-850 MB TROUGH
APPROACHING THE AREA FROM THE WEST. A LOW-LEVEL TROUGH WILL
PROGRESS THROUGH THE CAROLINAS TONIGHT BEFORE MOVING OFFSHORE BY 12Z
SAT MORNING.
PRECIPITATION AND TEMPERATURES THIS AFTERNOON:
CLOUDS HAVE ADVECTED INTO THE AREA QUICKLY THIS MORNING...AND WILL
BE SPREADING TOWARD KIXA QUICKLY AS WELL TOWARD THE NOON HOUR.
CONSIDERABLE CLOUDINESS TO THE SOUTHWEST WILL RESULT IN A MOSTLY
CLOUDY TO CLOUDY SKY ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON.
MUCH OF THE GUIDANCE SUPPORTS QPF IN PARTS OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN THIS AFTERNOON...WHILE THE RUC IS DRIEST.
TOOK A CLOSE LOOK AT THE RUC FOR ITS EVIDENCE OF DRIER CONDITIONS...
AND EVEN THAT MODEL SHARPENS THE INVERTED SURFACE TROUGH NEAR THE
COAST LATE THIS AFTERNOON AS THE LEFT EXIT REGION OF A 125KT 300MB
JET SHIFTS SOUTH. IN ADDITION...UNDER AMPLE 850MB THETA-E ADVECTION
SOUTHEAST...LOW-LEVEL LIFT AND CONVERGENCE INCREASE UNDER WEAK
DIFFLUENCE ALOFT IN VICINITY OF THE JET. MODEL SOUNDINGS FROM THE
RUC...WHILE SHOWING THE LOW-LEVEL DRY AIR ON THE 12Z UPPER-AIR
ANALYSIS OVER THE CAROLINAS AND TO THE SOUTHWEST...RAPIDLY MOISTEN
PARTICULARLY BETWEEN 21Z AND 00Z. RADAR TRENDS UPSTREAM SHOW THE DRY
AIR WILL BE TOUGH TO OVERCOME...BUT ANTICIPATE ENOUGH LIFT LATE IN
THE DAY TO EDGE LATE-DAY CHANCES TO LIKELY MAINLY NEAR KMEB...
KFAY...AND KCTZ...WITH ONLY CHANCES TO ABOUT KJNX AND KGSB.
ELSEWHERE...THERE COULD BE ENOUGH MID-LEVEL MOISTURE AND LIFT FOR
SPRINKLES AS THE MID-LEVEL WAVE MOVES THROUGH THE AREA...WITH MODEL
SOUNDINGS FROM BOTH THE LATEST NAM AND RUC SUGGESTIVE OF DECENT
MOISTURE IN THE -10C TO -15C RANGE ALOFT. GIVEN THE RAPID ADVECTION
OF CLOUD COVER...NUDGED MAXES DOWN TO NEAR THE COLDEST GUIDANCE. -DJF
TONIGHT:
FORCING FOR ASCENT TONIGHT WILL BE A COMBINATION OF DPVA/HEIGHT
FALLS ASSOCIATED WITH THE UPPER LEVEL DISTURBANCE TRACKING ACROSS
THE AREA...LOW-LEVEL CONVERGENCE ASSOC/W THE ATTENDANT LOW-LEVEL
TROUGH...AND A NARROW CORRIDOR OF STRONGER WARM ADVECTION IN ADVANCE
OF THE LOW-LEVEL TROUGH. COMPARED TO YESTERDAY...THE LATEST 00Z
GUIDANCE INDICATES A RELATIVE BETTER CHANCE FOR BACKED LOW-LEVEL
FLOW (AND STRONGER WARM ADVECTION) OVER THE EASTERN CAROLINAS IN
ADVANCE OF THE APPROACHING LOW-LEVEL TROUGH BETWEEN 00-06Z TONIGHT.
HOWEVER...THE 00Z GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH
THE EVOLUTION OF THE LOW-LEVEL HEIGHT/WIND FIELDS OVER THE CENTRAL/
EASTERN CAROLINAS...AND THIS LENDS A FAIR AMOUNT OF UNCERTAINTY TO
THE PRECIP FORECAST. THE 00Z GFS/NAM SHOW ANYWHERE FROM 0.10" TO
0.50" OF RAIN EAST OF I-95...WHILE THE 00Z ECMWF SHOWS BARELY A
HUNDREDTH IN THE COASTAL PLAIN AND DRY ELSEWHERE. WITH THE ABOVE IN
MIND...HAVE MADE SOME CHANGES TO THE PREVIOUS FORECAST...CONFINING
THE HIGHEST PRECIP CHANCES (60-70%) EAST OF I-95...TAPERING TO
SLIGHT/LOW CHANCE JUST WEST OF THE HWY 1 CORRIDOR. EXPECT PRECIP
AMOUNTS OF 0.10" OR LESS...HIGHEST EAST OF I-95...ALTHOUGH LOCALLY
HIGHER AMOUNTS WILL BE POSSIBLE IF THE GFS/NAM SOLUTIONS ARE CLOSER
TO REALITY THAN THE ECMWF. WITH MOST OF THE FORCING CONFINED TO THE
MID/UPPER LEVELS IN THE NW PIEDMONT AND A DRY ANTECEDENT LOW/MID
LEVEL AIRMASS IN PLACE...HAVE OPTED TO KEEP THE FCST DRY IN THE
TRIAD...ASIDE FROM A SLIGHT CHANCE OF SPRINKLES. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM FRIDAY...
OVERVIEW:
THE AFOREMENTIONED UPPER LEVEL DISTURBANCE WILL MOVE OFFSHORE BY 12Z
SAT. HOWEVER...A POTENT/AMPLIFYING UPPER LEVEL TROUGH WILL DIG
SOUTHEAST THROUGH THE GREAT LAKES/OH VALLEY INTO THE CENTRAL
APPALACHIANS SATURDAY MORNING...INTO THE MID-ATLANTIC/CAROLINAS
SATURDAY AFT/EVE...AND OFFSHORE THE CAROLINA COAST BY 12Z SUN
MORNING. THE LOW PRESSURE SYSTEM DEVELOPING ALONG THE CAROLINA COAST
TONIGHT IS EXPECTED TO RAPIDLY INTENSIFY SAT/SAT NIGHT AS IT TRACKS
NORTHEAST OFFSHORE THE NEW ENGLAND COAST INTO THE CANADIAN
MARITIMES...WHILE STRONG (1040-1045 MB) HIGH PRESSURE PUSHES SOUTH
THROUGH THE CENTRAL PLAINS AND BUILDS EAST TOWARD THE CAROLINAS AND
MID-ATLANTIC. A STRONG ARCTIC COLD FRONT WILL BE PRESENT AT THE
LEADING EDGE OF THE SFC HIGH BUILDING INTO THE AREA...WITH THE
FRONTAL PASSAGE OCCURRING RAPIDLY DURING MID/LATE SAT AFTERNOON.
TEMPERATURES:
DIFFICULT HIGH TEMP FCST SATURDAY. HIGHS WILL BE DRIVEN PRIMARILY BY
THE TIMING OF THE ARCTIC COLD FRONTAL PASSAGE. THE 00Z GUIDANCE IS
IN GOOD AGREEMENT SHOWING FROPA BETWEEN ROUGHLY 18-21Z SAT
AFTERNOON...WITH 1000-850 MB THICKNESSES RAPIDLY PLUMMETING FROM
1300-1330 METERS (NW-SE) TO 1260-1290 METERS BY 00Z SUNDAY. EXPECT
HIGHS TO OCCUR BY ~18Z WEST OF HIGHWAY 1...WITH TEMPS RAPIDLY
FALLING DURING THE MID/LATE AFTERNOON. EAST OF HIGHWAY 1...HIGHS
WILL OCCUR JUST PRIOR TO THE FRONTAL PASSAGE BETWEEN 17-20Z...WITH
TEMPS RAPIDLY FALLING BY LATE AFTERNOON. WITH THE ABOVE IN
MIND...WILL INDICATE HIGHS RANGING FROM THE LOWER/MID 40S IN THE NW
PIEDMONT TO THE LOWER/MID 50S IN THE SE COASTAL PLAIN. LOWS SAT
NIGHT WILL BE DRIVEN BY STRONG COLD ADVECTION. WITH THICKNESSES
~1250-1260 METERS EVERYWHERE BY 12Z SUN...EXPECT LOWS RANGING FROM
THE UPPER TEENS TO LOWER 20S NW PIEDMONT TO THE LOWER/MID 20S
ELSEWHERE.
PRECIPITATION:
WITH LOW-LEVEL DRYING IN THE WAKE OF THE SURFACE LOW TRACKING
NORTHEAST AWAY FROM THE CAROLINA COAST SATURDAY MORNING AND
STRENGTHENING WESTERLY FLOW/COLD ADVECTION IN THE LOWER LEVELS...
ANTICIPATE LITTLE CHANCE FOR PRECIP ON SATURDAY. HAVING SAID
THAT...SEVERAL POSITIVE FACTORS COULD OVERCOME THE NEGATIVE AND
RESULT IN ISOLD SHOWER ACTIVITY SATURDAY AFTERNOON. ALTHOUGH
LOW-LEVEL FLOW WILL BE UNIDIRECTIONAL...STRONG PRESSURE RISES
APPROACHING FROM THE WEST AS THE SFC HIGH BUILDS TOWARD THE AREA
WILL RESULT IN LOW-LEVEL SPEED CONVERGENCE ALONG THE LEADING EDGE OF
THE FRONT. IN THE UPPER LEVELS...PRODIGIOUS DPVA/HEIGHT FALLS WILL
BE PRESENT DURING THE DAY IN ASSOC/W THE AMPLIFYING UPPER LEVEL
TROUGH DIGGING INTO THE CAROLINAS. ADDITIONALLY...STRONG LOW-LEVEL
COLD ADVECTION COMBINED WITH VERY STRONG LAYER-LIFTING ASSOC/W THE
AMPLIFYING UPPER LEVEL TROUGH WILL RESULT IN STEEPENING LOW/MID
LEVEL LAPSE RATES DURING PEAK HEATING SATURDAY...POTENTIALLY
YIELDING A SMALL AMOUNT OF SFC-BASED INSTABILITY. WITH THE ABOVE IN
MIND...AND THE FACT THAT ALL OF THIS WILL BE COMING TOGETHER DURING
OR CLOSE-TO PEAK HEATING (EXCEPT FOR THE NW PIEDMONT)...WILL
INDICATE A SLIGHT CHANCE OF SHOWERS SAT AFTERNOON ALONG AND EAST OF
HWY 1.
WIND:
STRONG PRESSURE RISES ARE EXPECTED IN THE IMMEDIATE WAKE OF THE
ARCTIC COLD FRONT SATURDAY AFTERNOON/EVENING...AS MUCH AS 6MB/3HR.
ADDITIONALLY...THE AMPLIFYING UPPER LEVEL TROUGH IS PROGGED TO DIG
SOUTHEAST INTO THE CAROLINAS COINCIDENT WITH THE STRONGEST PRESSURE
RISES...ALLOWING FOR DEEPER MIXING VIA STEEPENING OF BOTH THE LOW
AND MID-LEVEL LAPSE RATES. FCST SOUNDINGS SHOW 40-50 KT NW FLOW AS
LOW AS 925 MB SAT AFT/EVE. WITH THE ABOVE IN MIND...THERE IS AT
LEAST A POTENTIAL FOR STRONG NW WINDS SATURDAY AFTERNOON/EVENING...
BETWEEN 4 PM AND MIDNIGHT. SUSTAINED WINDS OF 20-30 MPH WITH GUSTS
UP TO 40 MPH ARE EXPECTED WITH THE STRONGEST PRESSURE RISES...WITH A
POTENTIAL FOR OCCASIONAL/SPORADIC HIGHER GUSTS. ADDITIONALLY...
SHOULD ANY ISOLD SHOWER ACTIVITY DEVELOP DURING PEAK HEATING...
STRONGER FLOW ALOFT COULD BE TRANSPORTED TO THE GROUND. -VINCENT
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 304 AM FRIDAY...
VERY DRY AND COLD SUNDAY...FOLLOWED BY GRADUAL WARMING INTO
MID-WEEK.
THE HEART OF THE STRONG (~1040 MB) COLD SURFACE HIGH PRESSURE IS
FORECAST TO MOVE FROM THE MISSISSIPPI VALLEY EAST TO OUR OUR REGION
BY EARLY MONDAY. A BRISK COLD SUNDAY IS FORECAST AS THE PRESSURE
GRADIENT IS FORECAST TO FINALLY WEAKEN LATE IN THE DAY AS THE HIGH
PRESSURE APPROACHES. LITTLE CHANGE WAS NOTED IN THE FORECAST LOW
LEVEL THICKNESSES AND THE CAA PATTERN FROM PREVIOUS FORECASTS.
THEREFORE... HIGHS IN THE UPPER 30S IN THE NW PIEDMONT RANGING TO
42-43 IN THE SANDHILLS IS EXPECTED.
THE MAIN WEATHER HAZARD WILL BE THE WIND CHILL READINGS SUNDAY
MORNING. THEY ARE FORECAST TO RANGE BETWEEN 10 AND 15 EXCEPT 5 TO 10
DEGREES BETWEEN SUNRISE AND NOON IN THE WINSTON-SALEM AND
GREENSBORO AREAS. AGAIN... THE MOST BLUSTERY CONDITIONS ARE EXPECTED
DURING SUNDAY MORNING WITH WNW WINDS AT 10-15 MPH SUSTAINED... WITH
GUSTS TO 25 MPH. WINDS DURING THE AFTERNOON WILL GRADUALLY DIMINISH.
THIS WILL CONTINUE TO BE HIGHLIGHTED IN THE HAZARDOUS WEATHER
OUTLOOK.
AS THE HIGH SETTLES OVERHEAD SUNDAY NIGHT... IT WILL BE CLEAR WITH A
HARD FREEZE. LOWS SHOULD BE IN THE 20-23 RANGE WITH PLENTY OF
OPPORTUNITY FOR THE RURAL AREAS OF THE PIEDMONT AND SANDHILLS TO DIP
INTO THE UPPER TEENS WITH THE CALM DRY CONDITIONS EXPECTED.
MONDAY AND TUESDAY...
ANOTHER BIG CHANGE IS FORECAST FROM COLD AND DRY MONDAY TO MILDER
CONDITIONS TUESDAY. THIS OCCURS AS THE MODELS SHOW THE COLD UPPER
TROUGH LIFTING OUT RAPIDLY MONDAY... FOLLOWED CLOSELY BY THE COLD
SURFACE HIGHS EXIT OFF THE COAST BY MONDAY NIGHT. IN ADDITION...
MODELS AND ENSEMBLES CONTINUE TO WAVER ON THE STRENGTH AND TRACK OF
A DAMPENING MID-UPPER LEVEL DISTURBANCE THAT IS FORECAST TO TRACK
RAPIDLY EAST ACROSS THE NORTHERN GULF COAST STATES INTO THE TN
VALLEY LATE MONDAY. THE FAVORED EC ACTUALLY DAMPENS THIS WAVE IN THE
INCREASINGLY ZONAL FLOW ALOFT BY THE TIME IT REACHES THE
APPALACHIANS EARLY TUESDAY IN SO MUCH THAT IT DEPICTS ZERO QPF OVER
OUR REGION TUESDAY. THIS SOLUTION HAS SUPPORT FROM THE GFS AND
ENSEMBLE FORECASTS WHICH ALL DEPICT VERY LITTLE IN THE WAY OF QPF
FOR OUR AREA TUESDAY. IT MAKES SENSE IF THE MID-UPPER DISTURBANCE
WEAKENS AS MUCH AS FORECAST. IN ADDITION... THE LOW LEVEL SUB-CLOUD
LAYER IS FORECAST TO BE DRY TUESDAY... DUE TO THE LINGERING AFFECTS
OF THE COLD DRY POLAR HIGH THAT WILL BE JUST OUT TO SEA AT THAT
TIME. WE WILL LEAVE CURRENT POP IN AS CURRENTLY ADVERTISED WITH A
SLIM CHANCE OF LIGHT RAIN TUESDAY. THE P-TYPE WOULD LIKELY BE RAIN
(WITH HIGH CONFIDENCE) IF WE DO GET ANY MEASURABLE PRECIP. THIS
GIVEN THE FORECAST WARMING ALOFT WITH MID LEVEL THICKNESSES IN THE
1550+ RANGE AND RISING BETWEEN 12Z-18Z... AND THE LOW LEVEL
THICKNESSES IN THE 1310M RANGE AND RISING. SENSIBLE WEATHER...
MOSTLY SUNNY & CHILLY MONDAY. HIGHS 47-52. INCREASING CLOUDS LATE
MONDAY AND MONDAY NIGHT WITH LOWS IN THE 30S. MOSTLY CLOUDY TUESDAY
WITH A SLIM CHANCE OF LIGHT RAIN. HIGHS IN THE 40S AND 50S NE TO S.
FOR TUESDAY NIGHT THROUGH THURSDAY...
MILD. VARIABLY CLOUDY. A NEW STORM WITH A VERY WARM LOOK FOR OUR
REGION EXPECTED LATE WEEK. MAIN STORM TRACK IS FAVORED EITHER ALONG
THE APPALACHIANS OR JUST TO THE WEST. WE WILL KEEP POP EITHER LOW OR
OUT OF THE FORECAST SINCE THIS WILL BE DAYS 6-8 OUT IN WHICH THE
NEXT MAIN STORM IS EXPECTED TO APPROACH NC.
SENSIBLE WEATHER... LOWS WEDNESDAY AND THURSDAY IN THE 40S. HIGHS
WEDNESDAY AND THURSDAY IN THE UPPER 50S TO MID 60S.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 110 PM FRIDAY...
PRIMARY AVIATION IMPACTS THROUGH THE 18Z VALID TAF PERIOD WILL BE
GOOD POTENTIAL FOR PERIODS OF IFR CONDITIONS PARTICULARLY WITH
CEILINGS TONIGHT AT KRWI AND KFAY...AND INCREASE IN WIND SPEEDS
SATURDAY. WHERE THE AIR MASS WILL BE MORE MOIST...THE IFR CEILINGS
SHOULD BE MORE PERSISTENT TOWARD KRWI...AND WHILE NOT CURRENTLY
LIKELY...A FEW LOW CLOUDS AND POSSIBLY A BRIEF INSTANCE OF IFR
CONDITIONS COULD OCCUR AS FAR WEST AS ABOUT KRDU. IN THE INTERSTATE
95 CORRIDOR WILL BE THE GREATEST CHANCES FOR RAIN TONIGHT...FOLLOWED
BY GRADUAL DRYING AS WINDS VEER TO A MORE WEST AND NORTHWEST
COMPONENT OVERNIGHT.
WINDS FROM 290 TO 320 WILL INCREASE IN SPEED DURING THE DAY SATURDAY
AS A STRONG FRONT MOVES THROUGH. THE GREATEST THICKNESS PACKING AND
LIKELY ONSET OF MORE GUSTY WINDS SHOULD BE RIGHT AROUND 18Z TOWARD
KINT AND KGSO...AND BY 20Z THROUGHOUT THE REST OF CENTRAL NORTH
CAROLINA. BEFORE NIGHTFALL...PARTICULARLY FROM THE TRIAD TOWARD
KRDU...A FEW WIND GUSTS SHOULD APPROACH 35KT. THICKNESS PACKING
RELAXES SOME OVERNIGHT SATURDAY...BUT THE GRADIENT SHOULD BE TIGHT
ENOUGH UNDER THE AXIS OF THE UPPER TROUGH THAT GUSTY WINDS PERSIST
WELL INTO THE OVERNIGHT HOURS...THOUGH CURRENTLY NOT EXPECTED TO THE
DEGREE THEY WILL BE IN SOME AREAS SATURDAY AFTERNOON.
SUNDAY ONWARD...SEASONABLY GUSTY WINDS SUNDAY FROM THE NORTHWEST TO
20 TO 25KT UNDER VFR CONDITIONS. THE NEXT CHANCE OF SUB-VFR
CONDITIONS SHOULD BE TUESDAY NIGHT. THEN...INTO WEDNESDAY...THERE
MAY BE SUFFICIENT MOISTURE IN WARM-AIR ADVECTION FOR THE DEVELOPMENT
OF LOW CLOUDS IN PARTICULAR...BASED ON FORECAST UPPER-AIR SOUNDINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EST FRI FEB 10 2012
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL DEVELOP ALONG THE CAROLINA COAST
TONIGHT AS AN UPPER LEVEL DISTURBANCE CROSSES THE AREA. IN THE WAKE
OF THE LOW...A STRONG ARCTIC COLD FRONT WILL SWEEP ACROSS THE
CAROLINAS SATURDAY AFTERNOON. BEHIND THE FRONT...STRONG NORTHWEST
WINDS WILL USHER IN A MUCH COLDER AIRMASS INTO THE AREA SATURDAY
NIGHT AND SUNDAY.
&&
.NEAR TERM /THIS AFTERNOON AND TONIGHT/...
AS OF 1000 AM FRIDAY...
OVERVIEW:
SHORTWAVE ENERGY OVER MISSISSIPPI AND ALABAMA THIS MORNING WILL MOVE
ACROSS THE STATE THIS AFTERNOON AND THIS EVENING. FURTHER
UPSTREAM...A POTENT UPPER LEVEL TROUGH WILL DIG SOUTHEAST INTO THE
UPPER MIDWEST/UPPER GREAT LAKES...PROGRESSING INTO THE OHIO VALLEY
TONIGHT AND APPROACHING THE MID-ATLANTIC BY 12Z SAT. LOW-LEVEL FLOW
WILL BACK TO THE SOUTHWEST TODAY IN ADVANCE OF A SFC-850 MB TROUGH
APPROACHING THE AREA FROM THE WEST. A LOW-LEVEL TROUGH WILL
PROGRESS THROUGH THE CAROLINAS TONIGHT BEFORE MOVING OFFSHORE BY 12Z
SAT MORNING.
PRECIPITATION AND TEMPERATURES THIS AFTERNOON:
CLOUDS HAVE ADVECTED INTO THE AREA QUICKLY THIS MORNING...AND WILL
BE SPREADING TOWARD KIXA QUICKLY AS WELL TOWARD THE NOON HOUR.
CONSIDERABLE CLOUDINESS TO THE SOUTHWEST WILL RESULT IN A MOSTLY
CLOUDY TO CLOUDY SKY ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON.
MUCH OF THE GUIDANCE SUPPORTS QPF IN PARTS OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN THIS AFTERNOON...WHILE THE RUC IS DRIEST.
TOOK A CLOSE LOOK AT THE RUC FOR ITS EVIDENCE OF DRIER CONDITIONS...
AND EVEN THAT MODEL SHARPENS THE INVERTED SURFACE TROUGH NEAR THE
COAST LATE THIS AFTERNOON AS THE LEFT EXIT REGION OF A 125KT 300MB
JET SHIFTS SOUTH. IN ADDITION...UNDER AMPLE 850MB THETA-E ADVECTION
SOUTHEAST...LOW-LEVEL LIFT AND CONVERGENCE INCREASE UNDER WEAK
DIFFLUENCE ALOFT IN VICINITY OF THE JET. MODEL SOUNDINGS FROM THE
RUC...WHILE SHOWING THE LOW-LEVEL DRY AIR ON THE 12Z UPPER-AIR
ANALYSIS OVER THE CAROLINAS AND TO THE SOUTHWEST...RAPIDLY MOISTEN
PARTICULARLY BETWEEN 21Z AND 00Z. RADAR TRENDS UPSTREAM SHOW THE DRY
AIR WILL BE TOUGH TO OVERCOME...BUT ANTICIPATE ENOUGH LIFT LATE IN
THE DAY TO EDGE LATE-DAY CHANCES TO LIKELY MAINLY NEAR KMEB...
KFAY...AND KCTZ...WITH ONLY CHANCES TO ABOUT KJNX AND KGSB.
ELSEWHERE...THERE COULD BE ENOUGH MID-LEVEL MOISTURE AND LIFT FOR
SPRINKLES AS THE MID-LEVEL WAVE MOVES THROUGH THE AREA...WITH MODEL
SOUNDINGS FROM BOTH THE LATEST NAM AND RUC SUGGESTIVE OF DECENT
MOISTURE IN THE -10C TO -15C RANGE ALOFT. GIVEN THE RAPID ADVECTION
OF CLOUD COVER...NUDGED MAXES DOWN TO NEAR THE COLDEST GUIDANCE. -DJF
TONIGHT:
FORCING FOR ASCENT TONIGHT WILL BE A COMBINATION OF DPVA/HEIGHT
FALLS ASSOCIATED WITH THE UPPER LEVEL DISTURBANCE TRACKING ACROSS
THE AREA...LOW-LEVEL CONVERGENCE ASSOC/W THE ATTENDANT LOW-LEVEL
TROUGH...AND A NARROW CORRIDOR OF STRONGER WARM ADVECTION IN ADVANCE
OF THE LOW-LEVEL TROUGH. COMPARED TO YESTERDAY...THE LATEST 00Z
GUIDANCE INDICATES A RELATIVE BETTER CHANCE FOR BACKED LOW-LEVEL
FLOW (AND STRONGER WARM ADVECTION) OVER THE EASTERN CAROLINAS IN
ADVANCE OF THE APPROACHING LOW-LEVEL TROUGH BETWEEN 00-06Z TONIGHT.
HOWEVER...THE 00Z GUIDANCE CONTINUES TO HAVE A DIFFICULT TIME WITH
THE EVOLUTION OF THE LOW-LEVEL HEIGHT/WIND FIELDS OVER THE CENTRAL/
EASTERN CAROLINAS...AND THIS LENDS A FAIR AMOUNT OF UNCERTAINTY TO
THE PRECIP FORECAST. THE 00Z GFS/NAM SHOW ANYWHERE FROM 0.10" TO
0.50" OF RAIN EAST OF I-95...WHILE THE 00Z ECMWF SHOWS BARELY A
HUNDREDTH IN THE COASTAL PLAIN AND DRY ELSEWHERE. WITH THE ABOVE IN
MIND...HAVE MADE SOME CHANGES TO THE PREVIOUS FORECAST...CONFINING
THE HIGHEST PRECIP CHANCES (60-70%) EAST OF I-95...TAPERING TO
SLIGHT/LOW CHANCE JUST WEST OF THE HWY 1 CORRIDOR. EXPECT PRECIP
AMOUNTS OF 0.10" OR LESS...HIGHEST EAST OF I-95...ALTHOUGH LOCALLY
HIGHER AMOUNTS WILL BE POSSIBLE IF THE GFS/NAM SOLUTIONS ARE CLOSER
TO REALITY THAN THE ECMWF. WITH MOST OF THE FORCING CONFINED TO THE
MID/UPPER LEVELS IN THE NW PIEDMONT AND A DRY ANTECEDENT LOW/MID
LEVEL AIRMASS IN PLACE...HAVE OPTED TO KEEP THE FCST DRY IN THE
TRIAD...ASIDE FROM A SLIGHT CHANCE OF SPRINKLES. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM FRIDAY...
OVERVIEW:
THE AFOREMENTIONED UPPER LEVEL DISTURBANCE WILL MOVE OFFSHORE BY 12Z
SAT. HOWEVER...A POTENT/AMPLIFYING UPPER LEVEL TROUGH WILL DIG
SOUTHEAST THROUGH THE GREAT LAKES/OH VALLEY INTO THE CENTRAL
APPALACHIANS SATURDAY MORNING...INTO THE MID-ATLANTIC/CAROLINAS
SATURDAY AFT/EVE...AND OFFSHORE THE CAROLINA COAST BY 12Z SUN
MORNING. THE LOW PRESSURE SYSTEM DEVELOPING ALONG THE CAROLINA COAST
TONIGHT IS EXPECTED TO RAPIDLY INTENSIFY SAT/SAT NIGHT AS IT TRACKS
NORTHEAST OFFSHORE THE NEW ENGLAND COAST INTO THE CANADIAN
MARITIMES...WHILE STRONG (1040-1045 MB) HIGH PRESSURE PUSHES SOUTH
THROUGH THE CENTRAL PLAINS AND BUILDS EAST TOWARD THE CAROLINAS AND
MID-ATLANTIC. A STRONG ARCTIC COLD FRONT WILL BE PRESENT AT THE
LEADING EDGE OF THE SFC HIGH BUILDING INTO THE AREA...WITH THE
FRONTAL PASSAGE OCCURRING RAPIDLY DURING MID/LATE SAT AFTERNOON.
TEMPERATURES:
DIFFICULT HIGH TEMP FCST SATURDAY. HIGHS WILL BE DRIVEN PRIMARILY BY
THE TIMING OF THE ARCTIC COLD FRONTAL PASSAGE. THE 00Z GUIDANCE IS
IN GOOD AGREEMENT SHOWING FROPA BETWEEN ROUGHLY 18-21Z SAT
AFTERNOON...WITH 1000-850 MB THICKNESSES RAPIDLY PLUMMETING FROM
1300-1330 METERS (NW-SE) TO 1260-1290 METERS BY 00Z SUNDAY. EXPECT
HIGHS TO OCCUR BY ~18Z WEST OF HIGHWAY 1...WITH TEMPS RAPIDLY
FALLING DURING THE MID/LATE AFTERNOON. EAST OF HIGHWAY 1...HIGHS
WILL OCCUR JUST PRIOR TO THE FRONTAL PASSAGE BETWEEN 17-20Z...WITH
TEMPS RAPIDLY FALLING BY LATE AFTERNOON. WITH THE ABOVE IN
MIND...WILL INDICATE HIGHS RANGING FROM THE LOWER/MID 40S IN THE NW
PIEDMONT TO THE LOWER/MID 50S IN THE SE COASTAL PLAIN. LOWS SAT
NIGHT WILL BE DRIVEN BY STRONG COLD ADVECTION. WITH THICKNESSES
~1250-1260 METERS EVERYWHERE BY 12Z SUN...EXPECT LOWS RANGING FROM
THE UPPER TEENS TO LOWER 20S NW PIEDMONT TO THE LOWER/MID 20S
ELSEWHERE.
PRECIPITATION:
WITH LOW-LEVEL DRYING IN THE WAKE OF THE SURFACE LOW TRACKING
NORTHEAST AWAY FROM THE CAROLINA COAST SATURDAY MORNING AND
STRENGTHENING WESTERLY FLOW/COLD ADVECTION IN THE LOWER LEVELS...
ANTICIPATE LITTLE CHANCE FOR PRECIP ON SATURDAY. HAVING SAID
THAT...SEVERAL POSITIVE FACTORS COULD OVERCOME THE NEGATIVE AND
RESULT IN ISOLD SHOWER ACTIVITY SATURDAY AFTERNOON. ALTHOUGH
LOW-LEVEL FLOW WILL BE UNIDIRECTIONAL...STRONG PRESSURE RISES
APPROACHING FROM THE WEST AS THE SFC HIGH BUILDS TOWARD THE AREA
WILL RESULT IN LOW-LEVEL SPEED CONVERGENCE ALONG THE LEADING EDGE OF
THE FRONT. IN THE UPPER LEVELS...PRODIGIOUS DPVA/HEIGHT FALLS WILL
BE PRESENT DURING THE DAY IN ASSOC/W THE AMPLIFYING UPPER LEVEL
TROUGH DIGGING INTO THE CAROLINAS. ADDITIONALLY...STRONG LOW-LEVEL
COLD ADVECTION COMBINED WITH VERY STRONG LAYER-LIFTING ASSOC/W THE
AMPLIFYING UPPER LEVEL TROUGH WILL RESULT IN STEEPENING LOW/MID
LEVEL LAPSE RATES DURING PEAK HEATING SATURDAY...POTENTIALLY
YIELDING A SMALL AMOUNT OF SFC-BASED INSTABILITY. WITH THE ABOVE IN
MIND...AND THE FACT THAT ALL OF THIS WILL BE COMING TOGETHER DURING
OR CLOSE-TO PEAK HEATING (EXCEPT FOR THE NW PIEDMONT)...WILL
INDICATE A SLIGHT CHANCE OF SHOWERS SAT AFTERNOON ALONG AND EAST OF
HWY 1.
WIND:
STRONG PRESSURE RISES ARE EXPECTED IN THE IMMEDIATE WAKE OF THE
ARCTIC COLD FRONT SATURDAY AFTERNOON/EVENING...AS MUCH AS 6MB/3HR.
ADDITIONALLY...THE AMPLIFYING UPPER LEVEL TROUGH IS PROGGED TO DIG
SOUTHEAST INTO THE CAROLINAS COINCIDENT WITH THE STRONGEST PRESSURE
RISES...ALLOWING FOR DEEPER MIXING VIA STEEPENING OF BOTH THE LOW
AND MID-LEVEL LAPSE RATES. FCST SOUNDINGS SHOW 40-50 KT NW FLOW AS
LOW AS 925 MB SAT AFT/EVE. WITH THE ABOVE IN MIND...THERE IS AT
LEAST A POTENTIAL FOR STRONG NW WINDS SATURDAY AFTERNOON/EVENING...
BETWEEN 4 PM AND MIDNIGHT. SUSTAINED WINDS OF 20-30 MPH WITH GUSTS
UP TO 40 MPH ARE EXPECTED WITH THE STRONGEST PRESSURE RISES...WITH A
POTENTIAL FOR OCCASIONAL/SPORADIC HIGHER GUSTS. ADDITIONALLY...
SHOULD ANY ISOLD SHOWER ACTIVITY DEVELOP DURING PEAK HEATING...
STRONGER FLOW ALOFT COULD BE TRANSPORTED TO THE GROUND. -VINCENT
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 304 AM FRIDAY...
VERY DRY AND COLD SUNDAY...FOLLOWED BY GRADUAL WARMING INTO
MID-WEEK.
THE HEART OF THE STRONG (~1040 MB) COLD SURFACE HIGH PRESSURE IS
FORECAST TO MOVE FROM THE MISSISSIPPI VALLEY EAST TO OUR OUR REGION
BY EARLY MONDAY. A BRISK COLD SUNDAY IS FORECAST AS THE PRESSURE
GRADIENT IS FORECAST TO FINALLY WEAKEN LATE IN THE DAY AS THE HIGH
PRESSURE APPROACHES. LITTLE CHANGE WAS NOTED IN THE FORECAST LOW
LEVEL THICKNESSES AND THE CAA PATTERN FROM PREVIOUS FORECASTS.
THEREFORE... HIGHS IN THE UPPER 30S IN THE NW PIEDMONT RANGING TO
42-43 IN THE SANDHILLS IS EXPECTED.
THE MAIN WEATHER HAZARD WILL BE THE WIND CHILL READINGS SUNDAY
MORNING. THEY ARE FORECAST TO RANGE BETWEEN 10 AND 15 EXCEPT 5 TO 10
DEGREES BETWEEN SUNRISE AND NOON IN THE WINSTON-SALEM AND
GREENSBORO AREAS. AGAIN... THE MOST BLUSTERY CONDITIONS ARE EXPECTED
DURING SUNDAY MORNING WITH WNW WINDS AT 10-15 MPH SUSTAINED... WITH
GUSTS TO 25 MPH. WINDS DURING THE AFTERNOON WILL GRADUALLY DIMINISH.
THIS WILL CONTINUE TO BE HIGHLIGHTED IN THE HAZARDOUS WEATHER
OUTLOOK.
AS THE HIGH SETTLES OVERHEAD SUNDAY NIGHT... IT WILL BE CLEAR WITH A
HARD FREEZE. LOWS SHOULD BE IN THE 20-23 RANGE WITH PLENTY OF
OPPORTUNITY FOR THE RURAL AREAS OF THE PIEDMONT AND SANDHILLS TO DIP
INTO THE UPPER TEENS WITH THE CALM DRY CONDITIONS EXPECTED.
MONDAY AND TUESDAY...
ANOTHER BIG CHANGE IS FORECAST FROM COLD AND DRY MONDAY TO MILDER
CONDITIONS TUESDAY. THIS OCCURS AS THE MODELS SHOW THE COLD UPPER
TROUGH LIFTING OUT RAPIDLY MONDAY... FOLLOWED CLOSELY BY THE COLD
SURFACE HIGHS EXIT OFF THE COAST BY MONDAY NIGHT. IN ADDITION...
MODELS AND ENSEMBLES CONTINUE TO WAVER ON THE STRENGTH AND TRACK OF
A DAMPENING MID-UPPER LEVEL DISTURBANCE THAT IS FORECAST TO TRACK
RAPIDLY EAST ACROSS THE NORTHERN GULF COAST STATES INTO THE TN
VALLEY LATE MONDAY. THE FAVORED EC ACTUALLY DAMPENS THIS WAVE IN THE
INCREASINGLY ZONAL FLOW ALOFT BY THE TIME IT REACHES THE
APPALACHIANS EARLY TUESDAY IN SO MUCH THAT IT DEPICTS ZERO QPF OVER
OUR REGION TUESDAY. THIS SOLUTION HAS SUPPORT FROM THE GFS AND
ENSEMBLE FORECASTS WHICH ALL DEPICT VERY LITTLE IN THE WAY OF QPF
FOR OUR AREA TUESDAY. IT MAKES SENSE IF THE MID-UPPER DISTURBANCE
WEAKENS AS MUCH AS FORECAST. IN ADDITION... THE LOW LEVEL SUB-CLOUD
LAYER IS FORECAST TO BE DRY TUESDAY... DUE TO THE LINGERING AFFECTS
OF THE COLD DRY POLAR HIGH THAT WILL BE JUST OUT TO SEA AT THAT
TIME. WE WILL LEAVE CURRENT POP IN AS CURRENTLY ADVERTISED WITH A
SLIM CHANCE OF LIGHT RAIN TUESDAY. THE P-TYPE WOULD LIKELY BE RAIN
(WITH HIGH CONFIDENCE) IF WE DO GET ANY MEASURABLE PRECIP. THIS
GIVEN THE FORECAST WARMING ALOFT WITH MID LEVEL THICKNESSES IN THE
1550+ RANGE AND RISING BETWEEN 12Z-18Z... AND THE LOW LEVEL
THICKNESSES IN THE 1310M RANGE AND RISING. SENSIBLE WEATHER...
MOSTLY SUNNY & CHILLY MONDAY. HIGHS 47-52. INCREASING CLOUDS LATE
MONDAY AND MONDAY NIGHT WITH LOWS IN THE 30S. MOSTLY CLOUDY TUESDAY
WITH A SLIM CHANCE OF LIGHT RAIN. HIGHS IN THE 40S AND 50S NE TO S.
FOR TUESDAY NIGHT THROUGH THURSDAY...
MILD. VARIABLY CLOUDY. A NEW STORM WITH A VERY WARM LOOK FOR OUR
REGION EXPECTED LATE WEEK. MAIN STORM TRACK IS FAVORED EITHER ALONG
THE APPALACHIANS OR JUST TO THE WEST. WE WILL KEEP POP EITHER LOW OR
OUT OF THE FORECAST SINCE THIS WILL BE DAYS 6-8 OUT IN WHICH THE
NEXT MAIN STORM IS EXPECTED TO APPROACH NC.
SENSIBLE WEATHER... LOWS WEDNESDAY AND THURSDAY IN THE 40S. HIGHS
WEDNESDAY AND THURSDAY IN THE UPPER 50S TO MID 60S.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AS OF 1000 AM FRIDAY...
THROUGH 12Z SATURDAY:
VFR CONDITIONS WILL RULE THROUGH EARLY/MID AFTERNOON...WITH
DETERIORATING CONDITIONS IN THE COASTAL PLAIN (FAY/RWI) LATER THIS
AFTERNOON INTO TONIGHT. A LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP
ALONG THE CAROLINA COAST AS AN UPPER LEVEL DISTURBANCE PROGRESSES
EAST ACROSS THE AREA TONIGHT. MVFR/IFR CONDITIONS ASSOC/W RAIN ARE
EXPECTED TO DEVELOP NORTH INTO THE KFAY TERMINAL BY 19-22Z FOLLOWED
BY THE KRWI TERMINAL BY 22-01Z. UNCERTAINTY PERSISTS W/REGARD TO
WHETHER OR NOT SUB-VFR CONDITIONS WILL BE PRESENT FURTHER WEST AT
KRDU IN THE 00-06Z TIMEFRAME. THE BEST CHANCE FOR A PERIOD OF IFR
(AND POSSIBLY LIFR) CONDITIONS WILL BE AT KFAY/KRWI BETWEEN 22-06Z.
FURTHER WEST AT KINT/KGSO...VFR CONDITIONS ARE LIKELY TO PREVAIL
THROUGH THE TAF PERIOD.
LOOKING AHEAD:
ANY LINGERING SUB-VFR CONDITIONS AT FAY/RWI WILL END FROM WEST-EAST
BETWEEN 12-18Z SATURDAY AS THE LOW PRESSURE SYSTEM TRACKS NORTHEAST
AWAY FROM THE CAROLINAS...WITH VFR CONDITIONS THEREAFTER. IN THE
WAKE OF THE LOW...A STRONG ARCTIC COLD FRONT WILL SWEEP THROUGH THE
AREA FROM WEST-EAST BETWEEN 18-21Z SAT AFTERNOON. STRONG NORTHWEST
WINDS WILL BE PRESENT IN THE WAKE OF THE FRONT SAT AFTERNOON INTO
SAT NIGHT...BECOMING SUSTAINED AT 20-25 KT WITH GUSTS UP TO 35 KT.
THE STRONGEST WINDS ARE EXPECTED TO OCCUR BETWEEN 21Z SAT AND 03Z
SUNDAY WHEN THE MOST INTENSE PRESSURE RISES OCCUR. WINDS WILL WEAKEN
TO 10-15 KT SUSTAINED WITH GUSTS UP TO 20-25 KT DURING THE DAY
SUNDAY. VFR CONDITIONS WITH CLEAR SKIES ARE EXPECTED IN THE WAKE OF
THE FRONT THROUGH EARLY NEXT WEEK. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF/VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...DJF/VINCENT
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1014 AM CST FRI FEB 10 2012
.DISCUSSION...
TEMPS ACROSS THE BLACK FIELDS OF SOUTHEAST ND ARE ALREADY
RECOVERING THIS MORNING WITH GWINNER AT -2F. WILL KEEP THE
PREVIOUS SHIFTS IDEA OF WARMEST TEMPS OVER SOUTHEAST ND AND THE
TREES OF MN AND COOLEST TEMPS ACROSS THE SNOWPACK. MADE NO CHANGES
TO HIGH TEMPS BUT DID ADJUST THE MORNING RISE A BIT. DESPITE THE
EXTREME COLD WARNING EXPIRING IT WILL REMAIN PLENTY FRIGID
OUTDOORS TODAY.
&&
.AVIATION...
DO NOT REALLY EXPECT ANY CLOUD COVER THRU THE TAF PERIOD AND NORTH
WINDS SHOULD CONTINUE A SLOW DECREASE.
&&
.PREV DISCUSSION... /ISSUED 256 AM CST FRI FEB 10 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PRIMARY CHALLENGE IS WIND CHILL VALUES AND ASSOCIATED HEADLINES
THIS MORNING AND AGAIN EARLY SATURDAY. WITH NO PRECIPITATION
THROUGH THE WEEKEND...TEMPERATURES WILL BE THE MAIN FOCUS
THEREAFTER. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND WILL USE A
MODEL BLEND FOR THIS FORECAST PACKAGE.
08 UTC OBSERVATIONS ALREADY SHOWING WIND CHILL VALUES IN THE 30 TO
35 BELOW RANGE ALONG AND NORTH OF THE HIGHWAY TWO CORRIDOR. RUC 925
HPA TEMPERATURES DROP TO -25 C BY 12 UTC THIS MORNING ACROSS MUCH
OF THE NORTHERN FORECAST AREA...SO AIR TEMPERATURES STILL EXPECTED
TO DROP ANOTHER 5 TO 8 DEGREES THIS MORNING BEFORE RECOVERING.
SURFACE PRESSURE GRADIENT DOES NOT WEAKEN UNTIL LATER IN THE
DAY...SO NORTH WINDS FROM 10 TO 20 MPH WILL CONTINUE THROUGH AT
LEAST MID-MORNING. ALL THIS TO SAY...WILL ISSUE AN EXTREME COLD
WARNING FOR THE NORTHERN HALF OF THE FORECAST AREA FROM 09 UTC TO
16 UTC THIS MORNING WITH WIND CHILL VALUES IN THE 30 TO 40 BELOW
RANGE.
FOR THE REST OF THE DAY...EXPECT MOSTLY SUNNY CONDITIONS. WINDS
WILL WEAKEN A BIT THIS AFTERNOON...BUT TEMPERATURES WILL BE SLOW
TO RISE WITH AFTERNOON HIGHS IN THE SINGLE DIGITS ABOVE ZERO. SOME
PLACES WITH SNOW COVER WILL LIKELY STRUGGLE TO BREAK THE ZERO
MARK.
ATTENTION THEN TURNS TO SATURDAY MORNING. AIR TEMPERATURES LOOK TO
BE SIMILAR TO THIS MORNING (-10 TO -15 F)...BUT WITH A WEAKENING
PRESSURE GRADIENT AS CENTER OF SURFACE HIGH MOVES ACROSS THE
CENTRAL DAKOTAS...NORTHWEST WIND SHOULD STAY IN THE 5 TO 10 MPH
RANGE. WIND CHILL VALUES APPROACH 30 BELOW IN SPOTS...BUT DOES NOT
APPEAR TO BE AS WIDESPREAD OR QUITE AS COLD AS THIS MORNING. WILL
HOLD OFF ON ANY EXTREME COLD PRODUCTS FOR NOW...BUT SOMETHING THE
DAY SHIFT WILL NEED TO RE-EVALUATE.
SURFACE HIGH PRESSURE CONTINUES ACROSS THE NATION/S MID-SECTION
THROUGH THE WEEKEND WITH A GRADUAL WARMING TREND...SO THAT BY
SUNDAY AFTERNOON HIGHS CLIMB BACK INTO THE LOWER TO MID 20S. DO
NOT FORESEE ANY WIND CHILL PROBLEMS SUNDAY MORNING WITH LOWS IN
THE SINGLE DIGITS ABOVE OR BELOW ZERO AND RELATIVELY LIGHT WIND.
LONG TERM...MONDAY THROUGH THURSDAY NIGHT
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND PLACEMENT OF MINOR
SHORTWAVES MOVING THROUGH DURING THE PERIOD. ALL DETERMINISTIC
RUNS TAKE THE SHORTWAVE ON MONDAY FURTHER SOUTH SO WE STAY DRY. A
MORE SIGNIFICANT SHORTWAVE WILL DIG INTO MANITOBA BY WEDNESDAY AND
INTO THE PLAINS/UPPER MIDWEST ON THURSDAY...ALTHOUGH THERE ARE
STILL QUITE A FEW RUN TO RUN AND INTER-MODEL DIFFERENCES IN
PLACE. ECMWF HAS A SYSTEM COMING THROUGH THE NORTHERN PLAINS ON
FRIDAY AND DROPPING SOME PRECIP...ALTHOUGH WILL HAVE TO KEEP AN
EYE ON IT AS THAT SOLUTION SEEMS TO BE WETTER THAN THE OTHER
DETERMINISTIC MODELS AND MOST ENSEMBLE MEMBERS. TEMPS WILL
CONTINUE TO BE ABOVE SEASONAL AVERAGES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
256 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PRIMARY CHALLENGE IS WIND CHILL VALUES AND ASSOCIATED HEADLINES
THIS MORNING AND AGAIN EARLY SATURDAY. WITH NO PRECIPITATION
THROUGH THE WEEKEND...TEMPERATURES WILL BE THE MAIN FOCUS
THEREAFTER. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND WILL USE A
MODEL BLEND FOR THIS FORECAST PACKAGE.
08 UTC OBSERVATIONS ALREADY SHOWING WIND CHILL VALUES IN THE 30 TO
35 BELOW RANGE ALONG AND NORTH OF THE HIGHWAY TWO CORRIDOR. RUC 925
HPA TEMPERATURES DROP TO -25 C BY 12 UTC THIS MORNING ACROSS MUCH
OF THE NORTHERN FORECAST AREA...SO AIR TEMPERATURES STILL EXPECTED
TO DROP ANOTHER 5 TO 8 DEGREES THIS MORNING BEFORE RECOVERING.
SURFACE PRESSURE GRADIENT DOES NOT WEAKEN UNTIL LATER IN THE
DAY...SO NORTH WINDS FROM 10 TO 20 MPH WILL CONTINUE THROUGH AT
LEAST MID-MORNING. ALL THIS TO SAY...WILL ISSUE AN EXTREME COLD
WARNING FOR THE NORTHERN HALF OF THE FORECAST AREA FROM 09 UTC TO
16 UTC THIS MORNING WITH WIND CHILL VALUES IN THE 30 TO 40 BELOW
RANGE.
FOR THE REST OF THE DAY...EXPECT MOSTLY SUNNY CONDITIONS. WINDS
WILL WEAKEN A BIT THIS AFTERNOON...BUT TEMPERATURES WILL BE SLOW
TO RISE WITH AFTERNOON HIGHS IN THE SINGLE DIGITS ABOVE ZERO. SOME
PLACES WITH SNOW COVER WILL LIKELY STRUGGLE TO BREAK THE ZERO
MARK.
ATTENTION THEN TURNS TO SATURDAY MORNING. AIR TEMPERATURES LOOK TO
BE SIMILAR TO THIS MORNING (-10 TO -15 F)...BUT WITH A WEAKENING
PRESSURE GRADIENT AS CENTER OF SURFACE HIGH MOVES ACROSS THE
CENTRAL DAKOTAS...NORTHWEST WIND SHOULD STAY IN THE 5 TO 10 MPH
RANGE. WIND CHILL VALUES APPROACH 30 BELOW IN SPOTS...BUT DOES NOT
APPEAR TO BE AS WIDESPREAD OR QUITE AS COLD AS THIS MORNING. WILL
HOLD OFF ON ANY EXTREME COLD PRODUCTS FOR NOW...BUT SOMETHING THE
DAY SHIFT WILL NEED TO RE-EVALUATE.
SURFACE HIGH PRESSURE CONTINUES ACROSS THE NATION/S MID-SECTION
THROUGH THE WEEKEND WITH A GRADUAL WARMING TREND...SO THAT BY
SUNDAY AFTERNOON HIGHS CLIMB BACK INTO THE LOWER TO MID 20S. DO
NOT FORESEE ANY WIND CHILL PROBLEMS SUNDAY MORNING WITH LOWS IN
THE SINGLE DIGITS ABOVE OR BELOW ZERO AND RELATIVELY LIGHT WIND.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND PLACEMENT OF MINOR
SHORTWAVES MOVING THROUGH DURING THE PERIOD. ALL DETERMINISTIC
RUNS TAKE THE SHORTWAVE ON MONDAY FURTHER SOUTH SO WE STAY DRY. A
MORE SIGNIFICANT SHORTWAVE WILL DIG INTO MANITOBA BY WEDNESDAY AND
INTO THE PLAINS/UPPER MIDWEST ON THURSDAY...ALTHOUGH THERE ARE
STILL QUITE A FEW RUN TO RUN AND INTER-MODEL DIFFERENCES IN
PLACE. ECMWF HAS A SYSTEM COMING THROUGH THE NORTHERN PLAINS ON
FRIDAY AND DROPPING SOME PRECIP...ALTHOUGH WILL HAVE TO KEEP AN
EYE ON IT AS THAT SOLUTION SEEMS TO BE WETTER THAN THE OTHER
DETERMINISTIC MODELS AND MOST ENSEMBLE MEMBERS. TEMPS WILL
CONTINUE TO BE ABOVE SEASONAL AVERAGES.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE AT ALL TAF AIRFIELDS THE NEXT 24
HOURS. GUSTY NORTHERLY WIND EARLY THIS MORNING WILL GRADUALLY
DECREASE THROUGH THE DAY AS SURFACE HIGH PRESSURE BUILDS ACROSS
THE REGION.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...EXTREME COLD WARNING UNTIL 10 AM CST THIS MORNING FOR NDZ006>008-
014>016-024-026>030-054.
MN...EXTREME COLD WARNING UNTIL 10 AM CST THIS MORNING FOR MNZ001-002-
004>009-013>017-022-023.
&&
$$
ROGERS/JR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
321 PM EST FRI FEB 10 2012
.SYNOPSIS...
A STRONG UPPER LEVEL TROUGH WILL CARVE OUT ACROSS THE NORTHEAST
AND MID-ATLANTIC STATES THROUGH THE WEEKEND. A SHARP COLD FRONT
ASSOCIATED WITH THE UPPER LEVEL SYSTEM WILL SPREAD ARCTIC AIR INTO
THE COMMONWEALTH...WITH WIDESPREAD LAKE EFFECT AND UPSLOPE SNOW
SHOWERS BRINGING LIGHT TO LOCALLY MODERATE ACCUMULATIONS OVER THE
WESTERN MOUNTAINS INTO SUNDAY. HIGH PRESSURE SHOULD BRING A BRIEF
PERIOD OF FAIR AND DRY CONDITIONS TO START NEXT WEEK...WITH THE
THREAT OF WINTRY PRECIPITATION RETURNING BY NEXT TUESDAY.
TEMPERATURES ARE EXPECTED TO SLOWLY MODERATE OVER THE NEXT SEVEN
DAYS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
SEEDLINGS ALOFT ARE FALLING INTO THE LOW LEVEL MOISTURE/CLOUDS AND
CREATING SOME LIGHT SNOW OVER EASTERN OHIO AND PERHAPS INTO THE
WESTERN PART OF THE STATE. EXTRAPOLATION OF RADAR FEATURES AND
MELDING WITH HRRR DATA AND 12Z NAM PORTRAY A START TO THE SNOW
BEFORE DARK IN THE WESTERN HIGHLANDS AND BY 00Z ALONG THE MD
BORDER WEST OF CHAMBERSBURG. TEMPS ARE CLOSE TO 40 IN THE
SE...AND SLIGHTLY ABOVE FREEZING IN THE CENTRAL MTS. THE WEST AND
NORTH ARE BELOW FREEZING AND 8H TEMPS ARE WELL BELOW ZERO. THE
TEMPS ALOFT IN THE S ARE ALSO BELOW ZERO...BUT THE SFC TEMPS ABOVE
FREEZING AT THE ONSET OF ANY PRECIP IN THE SE WILL SPELL A MIX OF
RAIN AND SNOW. BUT THE TEMPS SHOULD DROP THROUGH THE NIGHT THERE
AND TURN TO ALL SNOW. THE SNOW MIGHT HAVE TROUBLE STICKING AT
FIRST IN THE SE...BUT COOLING AND PERSISTENCE OF THE SNOW WILL
EVENTUALLY WIN OUT. THE TROUGH IS WEAK BUT DEVELOPS EARLY TONIGHT
IN WV/VA AND SLIDES STEADILY TO THE EAST. IT IS THEN ABSORBED INTO
A GREATER TROUGH AND PULLED FAR ENOUGH AWAY TO END THE SNOW IN THE
SE RIGHT AROUND 12Z.
SNOW RATES WILL NOT BE THAT IMPRESSIVE...BUT A BAND OR TWO OF
SNOW WILL PUT TOTALS FOR THE OVERNIGHT AROUND 2 INCHES ACROSS
MOST/ALL OF THE AREA SOUTH OF RTE 22. HILL TOPS COULD GET 3 OR
SO...BUT THESE VALUES DO NOT LOOK WIDESPREAD ENOUGH FOR AN ADVY AT
THIS POINT. THE REST OF THE AREA SHOULD SEE LIGHTER SNOW AMOUNTS
BY MORNING. THE LONG-ADVERTISED ARCTIC FRONT SHOULD NOT IMPACT THE
AREA UNTIL SUNRISE...AS A WAVE DEVELOPS ALONG OR JUST AHEAD OF THE
FRONT IN NRN OH.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
THE SFC WAVE DEVELOPING ALONG THE FRONT WILL SLIDE INTO NWRN PA
LATE TONIGHT...AND DROP THROUGH THE AREA DURING THE DAY ON
SATURDAY - RIGHT ALONG THE LOWERED PRESSURES ON THE FRONT ITSELF.
THERE WILL MOST LIKELY BE A LULL IN THE SHSN OVER THE EAST AND
CENTRAL COS FOR MUCH OF THE MORNING...AND THEN THE FRONT ARRIVES.
BUT WITH LESS FANFARE THAN IN THE WEST. THE KINK IN THE FRONT WILL
PIVOT RIGHT OVERHEAD AND THIS WILL CREATE A SLOWER PROGRESSION TO
THE FRONT ACROSS THE AREA THAN HAD BEEN ANTICIPATED...BUT THE
EFFECTS SHOULD BE THE SAME WHEN IT DOES GET HERE. IN FACT...THE
SQUALLS COULD BE A LITTLE MORE INTENSE WITH LAPSE RATES PERHAPS
GETTING A LITTLE STEEPER DUE TO A TINY BIT MORE SFC HEATING BEFORE
THE FRONT REACHES THE WRN/CENT MTS. THE 8H TEMPS DROP
PRECIPITOUSLY THROUGH THE AFTERNOON IN THE WEST BUT NOT UNTIL
LATER IN THE DAY OR EVENING FOR THE CENTRAL MTS. WILL THEREFORE
PAINT JUST MAINLY STEADY TEMPS OR EVEN A SLIGHT MORNING BUMP
UPWARD IN MOST PLACES AND A MORE-NORMAL DIURNAL CURVE IN THE
SOUTHEAST.
ADVISORY AMOUNT SNOWS OF A WIDESPREAD 3 INCHES OR MORE IN 12 HRS
TIME WILL BE TOUGH TO FIND ANYWHERE. BUT THE WESTERN HIGHLANDS
WILL HAVE THE WORST OF THE CONDITIONS OVERALL...BUT NOT UNTIL
DURING THE DAYLIGHT HRS WHEN THE FRONT AND ASSOCD SHSN/SQUALLS
ARRIVE. THE CONDITIONS WILL NOT BE /BAD/ DUE ONLY TO SNOW AMOUNTS
NEAR 3 INCHES - WHICH AGAIN WILL BE HARD TO FIND - BUT FOR THE
COMBINATION OF SNOW...WIND AND POSSIBLY ICY ROADS AS THE FRONT
PASSES. THUS...WILL HOLD OFF ON ANY ADVYS FOR THE REST OF THE
AREA AT THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE MODELS ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE SHARP H5
TROF AXIS CROSSING CENTRAL PA SAT NGT...ACCOMPANIED BY -16 TO -18C
AIR AT H85 WHICH IS -1 TO -2SD BELOW NORMAL -- BUT NOT UNUSUAL FOR
THE MIDDLE OF FEBRUARY. BLUSTERY NW WINDS WILL DIRECT SLIGHTLY
MODIFIED ARCTIC AIR INTO THE REGION...PLUMMETING TEMPERATURES INTO
THE SINGLE DIGITS AND TEENS AND DROPPING WIND CHILLS NEAR TO BELOW
ZERO. STRONG LG SCALE LIFT AND STEEP MID-LEVEL LAPSE RATES WITH THE
TROF SHOULD ALLOW SNOW SHOWERS TO REACH INTO THE LWR SUSQ VLY/SERN
PA. CHANNELED NORTHWEST FLOW IN THE WAKE OF THE TROF WILL PRODUCE
LAKE EFFECT AND UPSLOPE SNOWS OVER THE LAUREL HIGHLANDS AND NW
MTNS...WITH ADDITIONAL LIGHT TO LOCALLY MODERATE ACCUMULATIONS
EXPECTED THRU SUNDAY.
CONCERNING THE MID-UPPER LEVEL FLOW ACRS THE NERN CONUS/SERN CANADA
SUNDAY INTO MONDAY...THERE IS STILL SOME SPREAD WITH TROF AMPLITUDE
AND TRACK OF THE EMBEDDED CLOSED LOW. THE NAM LEANS TO THE NRN SIDE
OF THE SPREAD WITH THE CLOSED LOW IN NRN QUEBEC AND EVENTUALLY
BECOMES FLATTER THAN THE GUIDANCE AVERAGE...WHILE THE CANADIAN GLBL
AND ECMWF DEFINE THE SRN SIDE OF THE ENVELOPE SHOWING THE CLOSED LOW
CENTERED JUST NE OF MAINE. GOOD CONTINUITY OF AN INTERMEDIATE TRACK
WITHIN THE SOLN SPREAD FOR THE CLOSED LOW LEADS TO RECOMMENDATION OF
A GFS/ECMWF COMPROMISE. THE MINOR MODEL DIFFS IN HANDLING THE POLAR
VORTEX SHOULD NOT HAVE MUCH OF AN IMPACT ON THE SENSIBLE WEATHER IN PA
WITH CONDITIONS REMAINING SEASONABLY COLD AND BRISK ON SUNDAY...WITH
SNOW SHOWERS BECOMING LIGHTER AND LESS WIDESPREAD INTO EARLY NEXT
WEEK AS SFC HIGH PRES SLIDES EWD FM THE MS/TN VLY.
FOLLOWING A BRIEF PERIOD OF FAIR AND DRY WX TO START OFF NEXT WEEK
THE THREAT OF LIGHT PCPN WILL RETURN TO THE FORECAST FROM LATE MON
NGT/EARLY TUES INTO WED...WITH PERHAPS A MORE SIGNIFICANT STORM
SYSTEM AFFECTING THE REGION SOMETIME LATE NEXT WEEK. THE 10/12Z
OPERATIONAL MODEL AND ENSEMBLE GUIDANCE STILL SHOWS UNCERTAINTY WITH
SHORTWAVE TIMING AND POTENTIAL PHASING OF STREAMS. THE SPLIT FLOW IS
IS WREAKING HAVOC WITH THE MODEL SOLUTIONS. AFTER A TASTE OF WINTER
THIS WEEKEND...EXPECT TEMPERATURES TO SLOWLY MODERATE IN TIME
EVENTUALLY CLIMBING BACK NEAR TO SLIGHTLY ABOVE NORMAL BY THE END OF
THE MEDIUM RANGE PD.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
A WEAK WAVE OF LOW PRESSURE WILL MOVE ACROSS THE CENTRAL
APPALACHIANS TONIGHT WHICH SHOULD BRING IFR CIGS AND VSBYS TO JST
LATE THIS EVENING AND THEN INTO MDT/LNS FOR LATER IN THE NIGHT.
MVFR CIGS POSSIBLE OVER THE REST OF THE AREA AS WELL IN -SN. THE
PRECIP AT MDT AND LNS WILL MOST LIKELY START AS RAIN OR SNOW
MELTING TO/MIXING WITH RAIN AS IT FALLS. PRECIP FROM THIS WAVE
SHOULD DIMINISH TO ALLOW FOR AT LEAST MVFR VSBY BEFORE 12Z SAT.
AFTER A BRIEF LULL IN SNOW A STRONG COLD FRONT WILL BRING SNOW
SHOWERS AND SQUALLS SAT MORNING TO THE WRN HIGHLANDS. THEN A
SECONDARY/WEAK LOW IN THE PRESSURES ALONG THE FRONT WHICH DEVELOPS
OVER NRN OH TONIGHT WILL DROP ACROSS THE AREA FROM NW TO SE DURING
THE DAY SAT. THIS AND THE FRONT WILL CREATE SNOW SHOWERS AND
LOCALLY HEAVIER SQUALLS FOR MOST OF THE TERMINALS IN THE LATE
MORNING AND AFTERNOON. BUT THE SHOWERS WILL MOST LIKELY BECOME
MORE SCT AND WEAKER AS THE FRONT DESCENDS INTO THE ERN VALLEYS.
EXPECT GUSTY WINDS...VERY LOW VSBYS AND CIGS IN THE NW HALF /BFD-
JST/ BETWEEN 15 AND 21Z SAT. LOW CIGS AND VSBYS ARE ALSO POSSIBLE
AT IPT-UNV-AOO AS WELL - MAINLY SAT AFTN.
OUTLOOK...
SAT NIGHT-SUN...MVFR/OCNL IFR NW IN SHSN. VFR ELSEWHERE.
MON...MAINLY VFR.
TUE-WED...MVFR IN -SN POSSIBLE. OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST SATURDAY FOR
PAZ004-005-010-017-024-033.
&&
$$
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
308 PM EST FRI FEB 10 2012
.SYNOPSIS...
HIGH PRESSURE SLIDE TO THE CAROLINA COAST WHILE A TROUGH OF LOW
PRESSURE DEVELOPS THE THE SOUTH OF THE STATE. THAT TROUGH WILL
MOVE TO THE EAST LATER TONIGHT AND WILL MAKE LIGHT SNOW ACROSS
MUCH OF THE AREA...WITH THE HIGHEST AMOUNTS ACROSS THE SOUTHERN
HALF OF THE AREA. A SHARPENING UPPER LEVEL TROUGH OVER EASTERN
CANADA AND THE NORTHEASTERN STATES WILL SEND A STRONG COLD FRONT
ACROSS THE STATE ON SATURDAY. THE FRONT WILL GENERATE WIDESPREAD
SNOW SHOWERS AND A FEW HEAVIER SQUALLS...AND A MODERATE SNOWFALL
IN THE WESTERN MOUNTAINS. BEHIND THE FRONT...MODIFIED ARCTIC AIR
WILL POUR INTO THE REGION FOR THE WEEKEND...AND GENERATE LAKE
EFFECT SNOW. THE TEMPERATURES WILL MODERATE BY MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SEEDLINGS ALOFT ARE FALLING INTO THE LOW LEVEL MOISTURE/CLOUDS AND
CREATING SOME LIGHT SNOW OVER EASTERN OHIO AND PERHAPS INTO THE
WESTERN PART OF THE STATE. EXTRAPOLATION OF RADAR FEATURES AND
MELDING WITH HRRR DATA AND 12Z NAM PORTRAY A START TO THE SNOW
BEFORE DARK IN THE WESTERN HIGHLANDS AND BY 00Z ALONG THE MD
BORDER WEST OF CHAMBERSBURG. TEMPS ARE CLOSE TO 40 IN THE
SE...AND SLIGHTLY ABOVE FREEZING IN THE CENTRAL MTS. THE WEST AND
NORTH ARE BELOW FREEZING AND 8H TEMPS ARE WELL BELOW ZERO. THE
TEMPS ALOFT IN THE S ARE ALSO BELOW ZERO...BUT THE SFC TEMPS ABOVE
FREEZING AT THE ONSET OF ANY PRECIP IN THE SE WILL SPELL A MIX OF
RAIN AND SNOW. BUT THE TEMPS SHOULD DROP THROUGH THE NIGHT THERE
AND TURN TO ALL SNOW. THE SNOW MIGHT HAVE TROUBLE STICKING AT
FIRST IN THE SE...BUT COOLING AND PERSISTENCE OF THE SNOW WILL
EVENTUALLY WIN OUT. THE TROUGH IS WEAK BUT DEVELOPS EARLY TONIGHT
IN WV/VA AND SLIDES STEADILY TO THE EAST. IT IS THEN ABSORBED INTO
A GREATER TROUGH AND PULLED FAR ENOUGH AWAY TO END THE SNOW IN THE
SE RIGHT AROUND 12Z.
SNOW RATES WILL NOT BE THAT IMPRESSIVE...BUT A BAND OR TWO OF
SNOW WILL PUT TOTALS FOR THE OVERNIGHT AROUND 2 INCHES ACROSS
MOST/ALL OF THE AREA SOUTH OF RTE 22. HILL TOPS COULD GET 3 OR
SO...BUT THESE VALUES DO NOT LOOK WIDESPREAD ENOUGH FOR AN ADVY AT
THIS POINT. THE REST OF THE AREA SHOULD SEE LIGHTER SNOW AMOUNTS
BY MORNING. THE LONG-ADVERTISED ARCTIC FRONT SHOULD NOT IMPACT THE
AREA UNTIL SUNRISE...AS A WAVE DEVELOPS ALONG OR JUST AHEAD OF THE
FRONT IN NRN OH.
&&
.SHORT TERM /SATURDAY/...
THE SFC WAVE DEVELOPING ALONG THE FRONT WILL SLIDE INTO NWRN PA
LATE TONIGHT...AND DROP THROUGH THE AREA DURING THE DAY ON
SATURDAY - RIGHT ALONG THE LOWERED PRESSURES ON THE FRONT ITSELF.
THERE WILL MOST LIKELY BE A LULL IN THE SHSN OVER THE EAST AND
CENTRAL COS FOR MUCH OF THE MORNING...AND THEN THE FRONT ARRIVES.
BUT WITH LESS FANFARE THAN IN THE WEST. THE KINK IN THE FRONT WILL
PIVOT RIGHT OVERHEAD AND THIS WILL CREATE A SLOWER PROGRESSION TO
THE FRONT ACROSS THE AREA THAN HAD BEEN ANTICIPATED...BUT THE
EFFECTS SHOULD BE THE SAME WHEN IT DOES GET HERE. IN FACT...THE
SQUALLS COULD BE A LITTLE MORE INTENSE WITH LAPSE RATES PERHAPS
GETTING A LITTLE STEEPER DUE TO A TINY BIT MORE SFC HEATING BEFORE
THE FRONT REACHES THE WRN/CENT MTS. THE 8H TEMPS DROP
PRECIPITOUSLY THROUGH THE AFTERNOON IN THE WEST BUT NOT UNTIL
LATER IN THE DAY OR EVENING FOR THE CENTRAL MTS. WILL THEREFORE
PAINT JUST MAINLY STEADY TEMPS OR EVEN A SLIGHT MORNING BUMP
UPWARD IN MOST PLACES AND A MORE-NORMAL DIURNAL CURVE IN THE
SOUTHEAST.
ADVISORY AMOUNT SNOWS OF A WIDESPREAD 3 INCHES OR MORE IN 12 HRS
TIME WILL BE TOUGH TO FIND ANYWHERE. BUT THE WESTERN HIGHLANDS
WILL HAVE THE WORST OF THE CONDITIONS OVERALL...BUT NOT UNTIL
DURING THE DAYLIGHT HRS WHEN THE FRONT AND ASSOCD SHSN/SQUALLS
ARRIVE. THE CONDITIONS WILL NOT BE /BAD/ DUE ONLY TO SNOW AMOUNTS
NEAR 3 INCHES - WHICH AGAIN WILL BE HARD TO FIND - BUT FOR THE
COMBINATION OF SNOW...WIND AND POSSIBLY ICY ROADS AS THE FRONT
PASSES. THUS...WILL HOLD OFF ON ANY ADVYS FOR THE REST OF THE
AREA AT THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE MODELS ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE SHARP H5
TROF AXIS CROSSING CENTRAL PA SAT NGT...ACCOMPANIED BY -16 TO -18C
AIR AT H85 WHICH IS -1 TO -2SD BELOW NORMAL -- BUT NOT UNUSUAL FOR
THE MIDDLE OF FEBRUARY. BLUSTERY NW WINDS WILL DIRECT SLIGHTLY
MODIFIED ARCTIC AIR INTO THE REGION...PLUMMETING TEMPERATURES INTO
THE SINGLE DIGITS AND TEENS AND DROPPING WIND CHILLS NEAR TO BELOW
ZERO. STRONG LG SCALE LIFT AND STEEP MID-LEVEL LAPSE RATES WITH THE
TROF SHOULD ALLOW SNOW SHOWERS TO REACH INTO THE LWR SUSQ VLY/SERN
PA. CHANNELED NORTHWEST FLOW IN THE WAKE OF THE TROF WILL PRODUCE
LAKE EFFECT AND UPSLOPE SNOWS OVER THE LAUREL HIGHLANDS AND NW
MTNS...WITH ADDITIONAL LIGHT TO LOCALLY MODERATE ACCUMULATIONS
EXPECTED THRU SUNDAY.
CONCERNING THE MID-UPPER LEVEL FLOW ACRS THE NERN CONUS/SERN CANADA
SUNDAY INTO MONDAY...THERE IS STILL SOME SPREAD WITH TROF AMPLITUDE
AND TRACK OF THE EMBEDDED CLOSED LOW. THE NAM LEANS TO THE NRN SIDE
OF THE SPREAD WITH THE CLOSED LOW IN NRN QUEBEC AND EVENTUALLY
BECOMES FLATTER THAN THE GUIDANCE AVERAGE...WHILE THE CANADIAN GLBL
AND ECMWF DEFINE THE SRN SIDE OF THE ENVELOPE SHOWING THE CLOSED LOW
CENTERED JUST NE OF MAINE. GOOD CONTINUITY OF AN INTERMEDIATE TRACK
WITHIN THE SOLN SPREAD FOR THE CLOSED LOW LEADS TO RECOMMENDATION OF
A GFS/ECMWF COMPROMISE. THE MINOR MODEL DIFFS IN HANDLING THE POLAR
VORTEX SHOULD NOT HAVE MUCH OF AN IMPACT ON THE SENSIBLE WEATHER IN PA
WITH CONDITIONS REMAINING SEASONABLY COLD AND BRISK ON SUNDAY...WITH
SNOW SHOWERS BECOMING LIGHTER AND LESS WIDESPREAD INTO EARLY NEXT
WEEK AS SFC HIGH PRES SLIDES EWD FM THE MS/TN VLY.
FOLLOWING A BRIEF PERIOD OF FAIR AND DRY WX TO START OFF NEXT WEEK
THE THREAT OF LIGHT PCPN WILL RETURN TO THE FORECAST FROM LATE MON
NGT/EARLY TUES INTO WED...WITH PERHAPS A MORE SIGNIFICANT STORM
SYSTEM AFFECTING THE REGION SOMETIME LATE NEXT WEEK. THE 10/12Z
OPERATIONAL MODEL AND ENSEMBLE GUIDANCE STILL SHOWS UNCERTAINTY WITH
SHORTWAVE TIMING AND POTENTIAL PHASING OF STREAMS. THE SPLIT FLOW IS
IS WREAKING HAVOC WITH THE MODEL SOLUTIONS. AFTER A TASTE OF WINTER
THIS WEEKEND...EXPECT TEMPERATURES TO SLOWLY MODERATE IN TIME
EVENTUALLY CLIMBING BACK NEAR TO SLIGHTLY ABOVE NORMAL BY THE END OF
THE MEDIUM RANGE PD.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
A WEAK WAVE OF LOW PRESSURE WILL MOVE ACROSS THE CENTRAL
APPALACHIANS TONIGHT WHICH SHOULD BRING IFR CIGS AND VSBYS TO JST
LATE THIS EVENING AND THEN INTO MDT/LNS FOR LATER IN THE NIGHT.
MVFR CIGS POSSIBLE OVER THE REST OF THE AREA AS WELL IN -SN. THE
PRECIP AT MDT AND LNS WILL MOST LIKELY START AS RAIN OR SNOW
MELTING TO/MIXING WITH RAIN AS IT FALLS. PRECIP FROM THIS WAVE
SHOULD DIMINISH TO ALLOW FOR AT LEAST MVFR VSBY BEFORE 12Z SAT.
AFTER A BRIEF LULL IN SNOW A STRONG COLD FRONT WILL BRING SNOW
SHOWERS AND SQUALLS SAT MORNING TO THE WRN HIGHLANDS. THEN A
SECONDARY/WEAK LOW IN THE PRESSURES ALONG THE FRONT WHICH DEVELOPS
OVER NRN OH TONIGHT WILL DROP ACROSS THE AREA FROM NW TO SE DURING
THE DAY SAT. THIS AND THE FRONT WILL CREATE SNOW SHOWERS AND
LOCALLY HEAVIER SQUALLS FOR MOST OF THE TERMINALS IN THE LATE
MORNING AND AFTERNOON. BUT THE SHOWERS WILL MOST LIKELY BECOME
MORE SCT AND WEAKER AS THE FRONT DESCENDS INTO THE ERN VALLEYS.
EXPECT GUSTY WINDS...VERY LOW VSBYS AND CIGS IN THE NW HALF /BFD-
JST/ BETWEEN 15 AND 21Z SAT. LOW CIGS AND VSBYS ARE ALSO POSSIBLE
AT IPT-UNV-AOO AS WELL - MAINLY SAT AFTN.
OUTLOOK...
SAT NIGHT-SUN...MVFR/OCNL IFR NW IN SHSN. VFR ELSEWHERE.
MON...MAINLY VFR.
TUE-WED...MVFR IN -SN POSSIBLE. OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
948 PM MST THU FEB 9 2012
.AVIATION...06Z TAF FORECASTS
MVFR CIGS ACROSS NORTHWESTERN AND CENTRAL SOUTH DAKOTA WILL
CONTINUE TO BACK INTO SOUTHWESTERN SOUTH DAKOTA AND NORTHEASTERN
WYOMING OVERNIGHT. LIGHT SNOW OR FLURRIES ARE ALSO EXPECTED TO
DEVELOP ACROSS PARTS OF NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA THROUGH EARLY FRIDAY MORNING. ALONG WITH MVFR CIGS...THE
SNOWFALL WILL RESULT IN AREAS OF MVFR VSBY WITH LOCALIZED IFR
CONDITIONS POSSIBLE...ESPECIALLY ALONG THE FOOTHILLS OF THE BLACK
HILLS.
&&
.PREV DISCUSSION... /ISSUED 513 PM MST THU FEB 9 2012/
DISCUSSION...A LARGE HUDSON BAY LOW WILL DOMINATE OUR WEATHER
THROUGH MUCH OF THE WEEKEND. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE...WITH A SUBSTANTIAL LOW-LEVEL TEMPERATURE GRADIENT ACROSS THE
CWA. THE COLD AIR AND BAROCLINIC ZONE WILL HELP TO SQUEEZE OUT THE
LIMITED MOISTURE...WITH SOME SPOTS IN NERN WY SEEING A FEW INCHES OF
ACCUMULATION.
UPPER JETS KISS OVER CWA TONIGHT AND INTENSIFY SLIGHTLY. THIS IS
FOLLOWED BY AN INFLUX OF COLDER AIR AND EVENTUALLY AN UPPER-LEVEL
TROUGH PASSAGE FRIDAY NIGHT AND SATURDAY MORNING. A STRONG...COLD
SURFACE HIGH PRESSURE ALSO WILL MOVE SOUTH ACROSS THE DAKOTAS ON
SATURDAY...BEHIND THE UPPER WAVE. AFTER THAT THE FLOW ALOFT BECOMES
WEAK...AND THUS AMENABLE TO SUBSTANTIAL LOW CLOUDS AND POSSIBLY SOME
FOG LATE SATURDAY THROUGH SUNDAY MRNG. LOW FROUDE FLOW THROUGH THE
PERIOD WILL PRECLUDE UPSLOPE SNOWS...BUT LOCAL ENHANCEMENT MAY OCCUR
IN THE NRN FOOTHILLS.
AN INITIAL SHOT OF LIGHT SNOW IS EXPECTED TONIGHT WITH THE LEADING
EDGE OF THE ARCTIC AIR...ESPECIALLY OVER NWRN THROUGH CNTRL SD. EVEN
THOUGH MOST MODELS HAVE NO INDICATION OF QPF...UPSTREAM OBS AND THE
HRRR AND RUC DO SUGGEST LIGHT SNOW SHOWERS MAY EVEN LINGER PAST 06Z
OVER MUCH OF THE SD PLAINS. OTHERWISE...THE BEST FORCING FOR UPWARD
MOTION WILL BE OVER NERN WY AND FAR SWRN SD FRIDAY AND FRIDAY NIGHT
AS TWO MORE JETS INTERACT. FRONTOGENESIS ALSO WILL BE ACTIVE ALONG
THE BAROCLINIC ZONE OVER NERN WY...AND THUS EXPECT A FEW INCHES OF
SNOWFALL. THE BAROCLINIC ZONE WILL BECOME SOMEWHAT DIFFUSE BY EARLY
SUNDAY...BUT IT STILL WILL RESIDE OVER THE SWRN CWA. THIS MAY
PROVIDE AN ADDITIONAL FOCUS FOR SNOW ON SUNDAY AS AN UPPER TROUGH
MOVES OVER THE FOUR CORNERS REGION.
LATEST MOS GUIDANCE HAS TRENDED COLDER WITH LOWS THE NEXT TWO DAYS.
WHILE THE TEMPS HAVE BEEN NUDGED LOWER...HAVE NOT GONE AS COLD AS
MOS...ESPECIALLY WHERE CLOUD COVER IS EXPECTED.
EXTENDED...UPPER LEVEL FLOW REMAINS NORTHWESTERLY OVER THE NORTHERN
PLAINS FOR EARLY NEXT WEEK. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW
POOR AGREEMENT ON TIMING AND PLACEMENT OF SEVERAL WEAK SHORTWAVES
THAT CROSS THE AREA. REGARDLESS...ATMOSPHERE REMAINS FAIRLY DRY WITH
THIS REGIME. WILL CONTINUE WITH A DRY FORECAST. TEMPERATURES IN THIS
TYPE OF FLOW SHOULD REMAIN NEAR AVERAGE.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1214 PM CST FRI FEB 10 2012
.UPDATE...
A BAND OF MDT TO HEAVY SNOW AND STRONG WINDS VIA LOW LEVEL
FRONTOGENESIS ALONG THE ARCTIC FRONT WILL SWEEP SOUTHWARD THROUGH
THE ERN CWA THROUGH THE EARLY AFTERNOON. INCREASED SNOW AMOUNTS TO
2 TO 3 INCHES WITH THE MOST ALONG THE LAKESHORE WHERE A BRIEF
PERIOD OF LAKE EFFECT SNOW IS EXPECTED BEFORE THE MAIN SNOW BAND
SETS UP OVER THE LAKE ON NLY WINDS. ALSO INCLUDED BLOWING SNOW
WITH THE EXPECTED STRONG WINDS...COLDER TEMPS...AND FALLING SNOW.
THERE MAY BE BRIEF PERIODS OF WHITEOUT CONDITIONS IN THE HEAVIER
SNOW BAND ALONG THE FRONT AS IT PROGRESSES SOUTH THROUGH ERN WI.
WILL BE ISSUING SPECIAL WEATHER STATEMENTS AND GRAPHICASTS TO
HANDLE THE BURST OF SNOW AND WIND TODAY. MOST OF THE ACCUMULATING
SNOW WILL BE OVER BY THE AFTERNOON RUSH HOUR WITH THE EXCEPTION
OF A LAKE EFFECT SNOW BAND FROM FAR SE MKE COUNTY THROUGH WIND
POINT IN RACINE AND ERN KENOSHA COUNTY.
&&
.AVIATION/18Z TAFS/...
HEAVIEST SNOW FROM AROUND MILWAUKEE TO WATERTOWN AND SOUTHWARD WILL
CONTINUE TO MOVE SOUTH INTO THIS AFTERNOON. VSBYS WILL GET DOWN TO
1/4 SM AT TIMES IN THIS HEAVIER AREA. ELSEWHERE SNOW WILL BE
LIGHTER...THOUGH GUSTY NORTH WINDS WILL RESULT IN BLOWING
SNOW...REDUCING VSBYS TO 1/2 TO 1 1/2 SM AT TIMES.
THE SNOW WILL FINALLY WIND NORTH TO SOUTH BY EVENING...WITH MVFR
CIGS LINGERING AT LEAST INTO THE EVENING. THE NAM HAS HIGHER LOW
LEVEL RH STICKING AROUND THROUGH THE NIGHT...SO WILL HAVE TO
CONSIDER KEEPING LOWER CIGS AROUND LATER. WILL HAVE TO EVALUATE
CLOSELY LOOK AT CIGS FOR TOMORROW AS WELL. CURRENTLY HAVE SCATTERED
CLOUDS IN THE FORECAST...BUT THE NAM WANTS TO KEEP THE LOW CLOUDS
GOING RIGHT THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 252 AM CST FRI FEB 10 2012/
VERY SHORT TERM...TODAY AND TONIGHT.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE KENOSHA AREA AROUND NOON.
A MID LEVEL SHORTWAVE WILL DROP SOUTHEAST AND EXTEND ACROSS EASTERN
LAKE SUPERIOR TO FAR SOUTHERN MINNESOTA BY NOON AND PUSH ACROSS
SOUTHEAST WISCONSIN EARLY THIS AFTERNOON. THIS IS SLOWING THE
SOUTHWARD PROGRESSION OF THE FRONT AND ALSO CAUSING WEAK UPWARD
MOTION TO CONTINUE AFTER THE FRONTAL PASSAGE. FORECAST SOUNDINGS
SHOW MOISTURE EXTENDING FROM THE LOW LEVELS THROUGHOUT THE MID
LEVELS. MID LEVELS THEN DRY BEHIND THE 500 MB TROUGH AXIS. AS THIS
HAPPENS LOW LEVEL LAPSE RATES INCREASE TO ALMOST 9 C/KM FROM THE
SURFACE TO 850 MB. THEREFORE EXPECT AN INITIAL SNOW SHOWER
POTENTIAL WITH THE FRONT...BUT SOME LIGHT SNOW SHOWERS/FLURRIES WILL
CONTINUE ACROSS SOUTH CENTRAL WISCONSIN THIS AFTERNOON AND ACROSS
SOUTHEAST WISCONSIN INTO THE EARLY EVENING.
NEXT PROBLEM IS INITIAL LAKE ENHANCEMENT BEHIND THE FRONT. NAM
FORECAST SOUNDINGS GENERATE LAKE ENHANCEMENT WITH AROUND 200 J/KG
OF CAPE EARLY THIS AFTERNOON AND AROUND 300 J/KG LATE THIS AFTERNOON
AND 400 J/KG EARLY THIS EVENING. DELTA T VALUES ARE MARGINAL THIS
AFTERNOON BUT JUMP TO MODERATE THIS EVENING OF -17 C. NAM SOUNDING
INDICATE THAT BY THE TIME THIS HAPPENS WINDS BECOME NORTH ACROSS
MUCH OF THE LOW LEVELS EXCEPT NORTHEAST IN A NARROW LAYER AROUND 4
THSD FT. RUC SOUNDINGS ARE MORE FAVORABLE WITH NNE OR NE WINDS FROM
JUST ABOVE THE SURFACE TO ALMOST 7 THSD FT.
WILL HOLD OFF ON ANY HEADLINES DUE TO THE UNCERTAINTY...BUT WILL
BUMP UP THE SNOW AMOUNTS NEAR THE LAKE.
AFTER MIDNIGHT THE 500 MB TROUGH REACHES LOWER MICHIGAN...AND THE
SOUNDINGS NEAR LAKE MICHIGAN SHOW A PRONOUNCED DRYING ABOVE
3 THSD FT.
SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT.
SPRAWLING...SLOW MOVING HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS
TONIGHT AND SATURDAY AS COLD AIR SETTLES OVER THE REGION. CORE OF
COLDEST AIR WITH 85H TEMPS AROUND -18C SHIFTS SLOWLY EWD ON
SAT...CONTINUING ON SUN AS THE LOW LEVEL WINDS BEGIN TO BACK MORE
NORTHWEST. NEVERTHELESS...DESPITE SUNSHINE DO NOT WANT TO WARM TEMPS
TOO FAST AS BLUSTERY NORTHWEST WINDS WL CONTINUE ON SAT AT THE
SFC...AND SOME AREAS WL LIKELY HAVE A FRESH LIGHT SNOW COVER. MAY BE
ABLE TO MIX TO AROUND 925H BOTH DAYS. HENCE DESPITE COLD BIAS DUE
TO PERSISTENT LACK OF SNOW...WL KEEP HIGHS IN THE 15 TO 20 RANGE
MOST AREAS SAT...AND IN MID-UPR 20S SUN. BLUSTERY NORTHWEST WINDS
OF 15 TO 25KTS WL ADD A STRONG CHILL TO THE AIR ON SAT. WIND CHILLS
WILL DROP TO BTWN 5 AND 15 BLO ZERO EARLY SAT MRNG AND AGAIN LATE
SAT NGT/EARLY SUN MRNG.
PERIOD OF MID-HIGH LEVEL CLOUDS ASSOCD WITH SURGE OF WARM AIR
ADVECTION MAY BRUSH PORTIONS OF SRN WI SAT NGT...BUT MAJORITY OF
CLOUDS REMAIN NORTH.
LONG TERM...MONDAY THROUGH THURSDAY.
EXTENDED GUIDANCE REMAINS IN REASONABLE AGREEMENT THROUGH EARLY
PERIODS. INCREASING SOUTHERLY WINDS ON THE BACKSIDE OF THE LARGE
HIGH PRESSURE AREA ALLOW MOISTURE TO INCREASE TO AROUND 0.4 INCH BY
LATER MONDAY. STRONGEST TEMP/MOISTURE ADVECTION HOWEVER REMAINS TO
THE SOUTH OF WI...HOWEVER ECMWF...GFS AND GEM-NHEM DO INCREASE
MOISTURE TO AT LEAST 10K FEET. ALTHOUGH FORCING REMAINS WEAK AS MID
LEVEL SHORT WAVE MOVES THROUGH MONDAY NIGHT...CONDENSATION PRESSURE
DEFICITS DECREASE TO LESS THAN 10MB ON MONDAY WITH WEAK ISENTROPIC
OMEGA. WITH SLR AROUND 15 TO 1...POSSIBLE FOR AN INCH OR TWO OF
SNOW MONDAY INTO MONDAY NIGHT. ENOUGH CONSISTENCY AND AGREEMENT TO
BUMP UP POPS TO LIKELY OVER MORE OF SRN WI MON AFTN CLOSER TO
STRONGER LOW LEVEL WEAK FORECING...AND IN THE SOUTHEAST MON NGT.
MID LEVEL WEAK WAVE STILL EXPECTED TO SLIDE OFF TO THE EAST BY
TUESDAY... HOWEVER PROGRESS HAS SLOWED A BIT AS SECONDARY WEAK WAVE
MOVES FROM THE UPPER MIDWEST INTO THE CENTRAL MS VALLEY. WL
CONTINUE DRYING TREND INTO TUE...BUT KEEP SCHC POPS IN THE FAR
SOUTHEAST TO REFLECT SLOWER MOVEMENT.
SEVERAL DAYS AGO...THOUGHT WE WERE HEADING TO A MORE UNSETTLED
PERIOD FOR LATER NEXT WEEK...AS MULTIPLE PIECES OF SHORT WAVE ENERGY
WERE EJECTED FROM PERSISTENT NRN PACIFIC LONG WAVE TROUGH INTO
CENTRAL CONUS. HOWEVER LAST DAY OR TWO...TREND HAS BEEN TOWARD
RETURN OF SPLIT FLOW ACROSS CONUS...WITH SRN STREAM REMAINING MORE
ACTIVE FROM TUE INTO THU. ECWMF FIRST TO PICK UP ON DRIER NRN
STREAM SIGNAL...AND LAST SEVERAL RUNS OF GFS NOW BACKING OFF ON
UNSETTLED MID-WEEK WX FOR UPPER MIDWEST. HPC ALSO TRENDING TOWARD
DRIER SOLUTION...FAVORING ECMWF OR ECMWF BLEND. FOR NOW...WL KEEP
POPS VERY LOW FOR LATE PDS WITH LOW CONFIDENCE. END RESULT...PALTRY
WINTER CONDITIONS TO CONTINUE.
AVIATION /12Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE BROUGHT MVFR STRATUS
ACROSS THE FORECAST AREA AND WILL PERSIST EARLY THIS MORNING.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE FAR SOUTHEAST TIP AROUND NOON. MAINLY CIGS
EXPECTED BEHIND THE FRONT ALONG WITH MVFR VSBYS IN SNOW SHOWERS WITH
SOME IFR VSBYS IN THE HEAVIER SNOW SHOWERS. APPEARS LAKE
ENHANCEMENT TO DEVELOP LATE THIS MORNING TOWARD SHEBOYGAN AND
ACROSS SOUTHEAST WISCONSIN FROM MILWAUKEE SOUTH THIS AFTERNOON.
OCCASIONAL IFR VSBYS EXPECTED WITH THIS SNOW. BY EVENING A LAKE
EFFECT SNOW BAND SHOULD SET UP MAINLY OVER WESTERN LAKE MICHIGAN AND
AFFECT AREAS MAINLY SOUTH OF THE ILLINOIS BORDER...BUT THERE IS A
POSSIBILITY OF SOME OF THIS SNOW AFFECTING THE SHORELINE AREAS
MAINLY SOUTH OF MILWAUKEE.
MARINE...
WINDS MAY BRIEFLY DROP BELOW SMALL CRAFT CRITERIA EARLY THIS MORNING
JUST AHEAD OF A TROUGH OF LOW PRESSURE EXTENDING ACROSS NORTHERN
LAKE MICHIGAN. AS AN ASSOCIATED STRONG COLD FRONT DROPS SOUTH
ACROSS SOUTHERN LAKE MICHIGAN LATER THIS MORNING WINDS WILL BECOME
NORTH AND INCREASE DRAMATICALLY. A FEW WIND GUSTS MAY APPROACH GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS.
DUE TO THE COLDER AIR WAVES EXPECTED TO INCREASE RAPIDLY BEHIND THE
FRONT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL OF THE SHORE
AREAS INTO SATURDAY AFTERNOON.
CONFIDENCE...
TODAY AND TONIGHT...MEDIUM.
SATURDAY THROUGH SUNDAY NIGHT...MEDIUM TO HIGH.
MONDAY AND MONDAY NIGHT...MEDIUM TO HIGH.
TUESDAY...MEDIUM.
WEDNESDAY AND THURSDAY...LOW TO MEDIUM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CST SATURDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
UPDATE...GEHRING/DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SATURDAY THROUGH THURSDAY...MBK
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1003 AM CST FRI FEB 10 2012
.UPDATE...
A BAND OF MDT TO HEAVY SNOW AND STRONG WINDS VIA LOW LEVEL
FRONTOGENESIS ALONG THE ARCTIC FRONT WILL SWEEP SOUTHWARD THROUGH
THE ERN CWA THROUGH THE EARLY AFTERNOON. INCREASED SNOW AMOUNTS TO
2 TO 3 INCHES WITH THE MOST ALONG THE LAKESHORE WHERE A BRIEF
PERIOD OF LAKE EFFECT SNOW IS EXPECTED BEFORE THE MAIN SNOW BAND
SETS UP OVER THE LAKE ON NLY WINDS. ALSO INCLUDED BLOWING SNOW
WITH THE EXPECTED STRONG WINDS...COLDER TEMPS...AND FALLING SNOW.
THERE MAY BE BRIEF PERIODS OF WHITEOUT CONDITIONS IN THE HEAVIER
SNOW BAND ALONG THE FRONT AS IT PROGRESSES SOUTH THROUGH ERN WI.
WILL BE ISSUING SPECIAL WEATHER STATEMENTS AND GRAPHICASTS TO
HANDLE THE BURST OF SNOW AND WIND TODAY. MOST OF THE ACCUMULATING
SNOW WILL BE OVER BY THE AFTERNOON RUSH HOUR WITH THE EXCEPTION
OF A LAKE EFFECT SNOW BAND FROM FAR SE MKE COUNTY THROUGH WIND
POINT IN RACINE AND ERN KENOSHA COUNTY.
&&
.AVIATION/18Z TAFS/...
HEAVIEST SNOW FROM AROUND MILWAUKEE TO WATERTOWN AND SOUTHWARD WILL
CONTINUE TO MOVE SOUTH INTO THIS AFTERNOON. VSBYS WILL GET DOWN TO
1/4 SM AT TIMES IN THIS HEAVIER AREA. ELSEWHERE SNOW WILL BE
LIGHTER...THOUGH GUSTY NORTH WINDS WILL RESULT IN BLOWING
SNOW...REDUCING VSBYS TO 1/2 TO 1 1/2 SM AT TIMES.
THE SNOW WILL FINALLY WIND NORTH TO SOUTH BY EVENING...WITH MVFR
CIGS LINGERING AT LEAST INTO THE EVENING. THE NAM HAS HIGHER LOW
LEVEL RH STICKING AROUND THROUGH THE NIGHT...SO WILL HAVE TO
CONSIDER KEEPING LOWER CIGS AROUND LATER. WILL HAVE TO EVALUATE
CLOSELY LOOK AT CIGS FOR TOMORROW AS WELL. CURRENTLY HAVE SCATTERED
CLOUDS IN THE FORECAST...BUT THE NAM WANTS TO KEEP THE LOW CLOUDS
GOING RIGHT THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 252 AM CST FRI FEB 10 2012/
VERY SHORT TERM...TODAY AND TONIGHT.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE KENOSHA AREA AROUND NOON.
A MID LEVEL SHORTWAVE WILL DROP SOUTHEAST AND EXTEND ACROSS EASTERN
LAKE SUPERIOR TO FAR SOUTHERN MINNESOTA BY NOON AND PUSH ACROSS
SOUTHEAST WISCONSIN EARLY THIS AFTERNOON. THIS IS SLOWING THE
SOUTHWARD PROGRESSION OF THE FRONT AND ALSO CAUSING WEAK UPWARD
MOTION TO CONTINUE AFTER THE FRONTAL PASSAGE. FORECAST SOUNDINGS
SHOW MOISTURE EXTENDING FROM THE LOW LEVELS THROUGHOUT THE MID
LEVELS. MID LEVELS THEN DRY BEHIND THE 500 MB TROUGH AXIS. AS THIS
HAPPENS LOW LEVEL LAPSE RATES INCREASE TO ALMOST 9 C/KM FROM THE
SURFACE TO 850 MB. THEREFORE EXPECT AN INITIAL SNOW SHOWER
POTENTIAL WITH THE FRONT...BUT SOME LIGHT SNOW SHOWERS/FLURRIES WILL
CONTINUE ACROSS SOUTH CENTRAL WISCONSIN THIS AFTERNOON AND ACROSS
SOUTHEAST WISCONSIN INTO THE EARLY EVENING.
NEXT PROBLEM IS INITIAL LAKE ENHANCEMENT BEHIND THE FRONT. NAM
FORECAST SOUNDINGS GENERATE LAKE ENHANCEMENT WITH AROUND 200 J/KG
OF CAPE EARLY THIS AFTERNOON AND AROUND 300 J/KG LATE THIS AFTERNOON
AND 400 J/KG EARLY THIS EVENING. DELTA T VALUES ARE MARGINAL THIS
AFTERNOON BUT JUMP TO MODERATE THIS EVENING OF -17 C. NAM SOUNDING
INDICATE THAT BY THE TIME THIS HAPPENS WINDS BECOME NORTH ACROSS
MUCH OF THE LOW LEVELS EXCEPT NORTHEAST IN A NARROW LAYER AROUND 4
THSD FT. RUC SOUNDINGS ARE MORE FAVORABLE WITH NNE OR NE WINDS FROM
JUST ABOVE THE SURFACE TO ALMOST 7 THSD FT.
WILL HOLD OFF ON ANY HEADLINES DUE TO THE UNCERTAINTY...BUT WILL
BUMP UP THE SNOW AMOUNTS NEAR THE LAKE.
AFTER MIDNIGHT THE 500 MB TROUGH REACHES LOWER MICHIGAN...AND THE
SOUNDINGS NEAR LAKE MICHIGAN SHOW A PRONOUNCED DRYING ABOVE
3 THSD FT.
SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT.
SPRAWLING...SLOW MOVING HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS
TONIGHT AND SATURDAY AS COLD AIR SETTLES OVER THE REGION. CORE OF
COLDEST AIR WITH 85H TEMPS AROUND -18C SHIFTS SLOWLY EWD ON
SAT...CONTINUING ON SUN AS THE LOW LEVEL WINDS BEGIN TO BACK MORE
NORTHWEST. NEVERTHELESS...DESPITE SUNSHINE DO NOT WANT TO WARM TEMPS
TOO FAST AS BLUSTERY NORTHWEST WINDS WL CONTINUE ON SAT AT THE
SFC...AND SOME AREAS WL LIKELY HAVE A FRESH LIGHT SNOW COVER. MAY BE
ABLE TO MIX TO AROUND 925H BOTH DAYS. HENCE DESPITE COLD BIAS DUE
TO PERSISTENT LACK OF SNOW...WL KEEP HIGHS IN THE 15 TO 20 RANGE
MOST AREAS SAT...AND IN MID-UPR 20S SUN. BLUSTERY NORTHWEST WINDS
OF 15 TO 25KTS WL ADD A STRONG CHILL TO THE AIR ON SAT. WIND CHILLS
WILL DROP TO BTWN 5 AND 15 BLO ZERO EARLY SAT MRNG AND AGAIN LATE
SAT NGT/EARLY SUN MRNG.
PERIOD OF MID-HIGH LEVEL CLOUDS ASSOCD WITH SURGE OF WARM AIR
ADVECTION MAY BRUSH PORTIONS OF SRN WI SAT NGT...BUT MAJORITY OF
CLOUDS REMAIN NORTH.
LONG TERM...MONDAY THROUGH THURSDAY.
EXTENDED GUIDANCE REMAINS IN REASONABLE AGREEMENT THROUGH EARLY
PERIODS. INCREASING SOUTHERLY WINDS ON THE BACKSIDE OF THE LARGE
HIGH PRESSURE AREA ALLOW MOISTURE TO INCREASE TO AROUND 0.4 INCH BY
LATER MONDAY. STRONGEST TEMP/MOISTURE ADVECTION HOWEVER REMAINS TO
THE SOUTH OF WI...HOWEVER ECMWF...GFS AND GEM-NHEM DO INCREASE
MOISTURE TO AT LEAST 10K FEET. ALTHOUGH FORCING REMAINS WEAK AS MID
LEVEL SHORT WAVE MOVES THROUGH MONDAY NIGHT...CONDENSATION PRESSURE
DEFICITS DECREASE TO LESS THAN 10MB ON MONDAY WITH WEAK ISENTROPIC
OMEGA. WITH SLR AROUND 15 TO 1...POSSIBLE FOR AN INCH OR TWO OF
SNOW MONDAY INTO MONDAY NIGHT. ENOUGH CONSISTENCY AND AGREEMENT TO
BUMP UP POPS TO LIKELY OVER MORE OF SRN WI MON AFTN CLOSER TO
STRONGER LOW LEVEL WEAK FORECING...AND IN THE SOUTHEAST MON NGT.
MID LEVEL WEAK WAVE STILL EXPECTED TO SLIDE OFF TO THE EAST BY
TUESDAY... HOWEVER PROGRESS HAS SLOWED A BIT AS SECONDARY WEAK WAVE
MOVES FROM THE UPPER MIDWEST INTO THE CENTRAL MS VALLEY. WL
CONTINUE DRYING TREND INTO TUE...BUT KEEP SCHC POPS IN THE FAR
SOUTHEAST TO REFLECT SLOWER MOVEMENT.
SEVERAL DAYS AGO...THOUGHT WE WERE HEADING TO A MORE UNSETTLED
PERIOD FOR LATER NEXT WEEK...AS MULTIPLE PIECES OF SHORT WAVE ENERGY
WERE EJECTED FROM PERSISTENT NRN PACIFIC LONG WAVE TROUGH INTO
CENTRAL CONUS. HOWEVER LAST DAY OR TWO...TREND HAS BEEN TOWARD
RETURN OF SPLIT FLOW ACROSS CONUS...WITH SRN STREAM REMAINING MORE
ACTIVE FROM TUE INTO THU. ECWMF FIRST TO PICK UP ON DRIER NRN
STREAM SIGNAL...AND LAST SEVERAL RUNS OF GFS NOW BACKING OFF ON
UNSETTLED MID-WEEK WX FOR UPPER MIDWEST. HPC ALSO TRENDING TOWARD
DRIER SOLUTION...FAVORING ECMWF OR ECMWF BLEND. FOR NOW...WL KEEP
POPS VERY LOW FOR LATE PDS WITH LOW CONFIDENCE. END RESULT...PALTRY
WINTER CONDITIONS TO CONTINUE.
AVIATION /12Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE BROUGHT MVFR STRATUS
ACROSS THE FORECAST AREA AND WILL PERSIST EARLY THIS MORNING.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE FAR SOUTHEAST TIP AROUND NOON. MAINLY CIGS
EXPECTED BEHIND THE FRONT ALONG WITH MVFR VSBYS IN SNOW SHOWERS WITH
SOME IFR VSBYS IN THE HEAVIER SNOW SHOWERS. APPEARS LAKE
ENHANCEMENT TO DEVELOP LATE THIS MORNING TOWARD SHEBOYGAN AND
ACROSS SOUTHEAST WISCONSIN FROM MILWAUKEE SOUTH THIS AFTERNOON.
OCCASIONAL IFR VSBYS EXPECTED WITH THIS SNOW. BY EVENING A LAKE
EFFECT SNOW BAND SHOULD SET UP MAINLY OVER WESTERN LAKE MICHIGAN AND
AFFECT AREAS MAINLY SOUTH OF THE ILLINOIS BORDER...BUT THERE IS A
POSSIBILITY OF SOME OF THIS SNOW AFFECTING THE SHORELINE AREAS
MAINLY SOUTH OF MILWAUKEE.
MARINE...
WINDS MAY BRIEFLY DROP BELOW SMALL CRAFT CRITERIA EARLY THIS MORNING
JUST AHEAD OF A TROUGH OF LOW PRESSURE EXTENDING ACROSS NORTHERN
LAKE MICHIGAN. AS AN ASSOCIATED STRONG COLD FRONT DROPS SOUTH
ACROSS SOUTHERN LAKE MICHIGAN LATER THIS MORNING WINDS WILL BECOME
NORTH AND INCREASE DRAMATICALLY. A FEW WIND GUSTS MAY APPROACH GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS.
DUE TO THE COLDER AIR WAVES EXPECTED TO INCREASE RAPIDLY BEHIND THE
FRONT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL OF THE SHORE
AREAS INTO SATURDAY AFTERNOON.
CONFIDENCE...
TODAY AND TONIGHT...MEDIUM.
SATURDAY THROUGH SUNDAY NIGHT...MEDIUM TO HIGH.
MONDAY AND MONDAY NIGHT...MEDIUM TO HIGH.
TUESDAY...MEDIUM.
WEDNESDAY AND THURSDAY...LOW TO MEDIUM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CST SATURDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
UPDATE...GEHRING/DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
SATURDAY THROUGH THURSDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
237 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUDS/TEMPERATURES/PRECIPITATION
TODAY...THEN WIND CHILLS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S INTO THE NORTHWEST
TERRITORIES OF CANADA...AND TROUGHING FROM THE DAKOTAS INTO QUEBEC.
WITHIN THIS TROUGH...A SHORTWAVE WAS PRESENT FROM NORTH DAKOTA INTO
NORTHERN MINNESOTA. A REMNANT STREAM OF PACIFIC MOISTURE AND DPVA
AHEAD OF THE SHORTWAVE HELPING TO PRODUCE A BAND OF MID-CLOUDS FROM
NORTHEAST SOUTH DAKOTA TO LAKE SUPERIOR. BELOW THIS...AN AREA OF
STRATUS RESULTING FROM MOISTURE TRAPPED IN A COLD FRONTAL INVERSION
WAS PRESENT FROM NORTHWEST IOWA INTO NORTHERN WISCONSIN. SOME LIGHT
SNOW WAS ALSO FALLING OUT OF THIS STRATUS OVER THE NORTH HALF OF
WISCONSIN...DUE TO THE PRESENCE OF LOW LEVEL FRONTOGENESIS PER RUC
ANALYSIS. THE THERMAL CONTRAST OF THE FRONTOGENESIS COULD BE SEEN
FROM A 00Z 850MB SOUNDING PLOT...NOTED BY A -6C TEMP AT MPX AND -17C
AT INL. AT THE SURFACE...A COLD FRONTAL BOUNDARY STRETCHED FROM
NORTHERN LAKE MICHIGAN SOUTHWEST TO DES MOINES...WHILE A 1041MB
ARCTIC HIGH PRESSURE AREA WAS OVER CENTRAL SASKATCHEWAN.
TODAY AND TONIGHT...SHORTWAVE OVER NORTH DAKOTA AND NORTHERN
MINNESOTA IS PROGGED TO MOVE THROUGH THE FORECAST AREA BETWEEN
15-21Z TODAY...ALLOWING THE ARCTIC HIGH PRESSURE AREA OVER
SASKATCHEWAN TO DROP SOUTH IN ITS WAKE. BY 12Z SATURDAY...THE HIGH
SHOULD BE SITUATED IN THE DAKOTAS. WITH THE HIGH WELL OFF TO THE
WEST...ANTICIPATING BLUSTERY CONDITIONS ACROSS MUCH OF THE FORECAST
AREA THROUGH TONIGHT. WIND DIRECTION IS A LITTLE INTERESTING. DUE TO
THE TRACK OF THE DEPARTING COLD FRONT...THE SURFACE-850MB WINDS ARE
MORE NORTH TO NORTHEAST TODAY...THEN SWITCHES TO THE NORTHWEST
TONIGHT. THIS WIND DIRECTION PATTERN MEANS THAT LOW LEVEL MOISTURE/
CLOUDS MAY GET STUCK OVER THE FORECAST AREA MORE TODAY...AIDED BY
MOISTENING OFF LAKE SUPERIOR. ONCE THE WINDS GO NORTHWEST...THE DRY
ARCTIC AIR CAN FLOW IN AND CLEAR OUT THE STRATUS. ONE CAVEAT IS THAT
RIGHT NOW THE AIR OVER NORTHERN ONTARIO IS DRIER THAN THE MODELS
SUGGEST. WILL HAVE TO WATCH TO SEE THROUGH THE DAY TODAY ON HOW MUCH
OF THIS DRIER AIR OVER NORTHERN ONTARIO ADVECTS SOUTH. NEXT CONCERN
IS THE PRECIPITATION. THE 10.00Z NAM AND HRRR RUNS HAVE SHOWN SOME
VERY LIGHT SNOW/FLURRIES...MOSTLY ALONG AND EAST OF THE MISSISSIPPI
RIVER THIS MORNING. LOW LEVEL FRONTOGENETICAL FORCING APPEARS TO BE
THE MAIN PRODUCTION FEATURE...WITH THE SNOW MORE LIKELY TO OCCUR DUE
TO THE STRATUS EVENTUALLY INTERSECTING THE DENDRITIC GROWTH ZONE AS
THE COLDER AIR MOVES IN. A FEW TENTHS SEEM POSSIBLE. HAVE LEFT SOME
FLURRIES IN FOR THE AFTERNOON TOO...BUT THINK THE BULK OF ANY
ACCUMULATING TYPE SNOW WOULD BE OFF TO THE EAST WHERE THE LOW LEVEL
FRONTOGENESIS IS EXPECTED. FINAL CONCERN IS TEMPERATURES. 850MB
TEMPS REALLY DROP TODAY...FROM -8C SOUTHEAST TO -16C NORTHWEST
ACROSS THE FORECAST AREA AT 12Z...TO BASICALLY AROUND -20C AT 00Z.
WITH STRATUS IN PLACE AND FALLING 850MB TEMPS...LOOK FOR SURFACE
TEMPERATURES TO SLOWLY FALL THROUGH THE DAY...DROPPING WIND CHILLS.
TONIGHT...THE TEMPERATURE FALL WILL MAINLY BE A RESULT OF ADVECTION
DUE TO BLUSTERY CONDITIONS KEEPING THE BOUNDARY LAYER MIXED.
STILL...LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO SUGGESTED BY
GUIDANCE AND THE PREVIOUS FORECAST SEEM REASONABLE. MAY NEED WIND
CHILL ADVISORIES FOR PORTIONS OF THE AREA VERY LATE...MOST LIKELY
TAYLOR AND CLARK ZONES. GIVEN SUCH A SMALL AREA AND MARGINAL WIND
CHILLS AT THAT...HELD OFF ON ISSUING AN ADVISORY AT THIS TIME.
SATURDAY THROUGH SUNDAY NIGHT...FAIRLY QUIET PERIOD EXPECTED AS
500MB HEIGHTS GRADUALLY BUILD. ARCTIC HIGH PRESSURE AREA NEVER
BUILDS OVER THE AREA...TRACKING MORE SOUTH TO THE LOWER MISSISSIPPI
RIVER VALLEY BY MID-DAY SUNDAY. THIS TRACK SHOULD KEEP CONDITIONS
FROM DECOUPLING SATURDAY NIGHT...PREVENTING ANY DRAMATIC TEMPERATURE
FALL FROM RADIATIONAL COOLING. ONLY REAL CONCERN IS SUNDAY NIGHT.
DURING THIS PERIOD...MODELS HAVE UPPER TROUGHING CROSSING THE
WESTERN U.S. TOWARDS THE PLAINS WITH RIDGING BUILDING UP TOWARDS THE
FORECAST AREA. 10.00Z NAM HINTS THAT A FEW WEAK SHORTWAVES MAY COME
OUT OF THE TROUGH AND APPROACH THE AREA BY 12Z MONDAY. WITH THESE
SHORTWAVES...THE NAM BRINGS SOME PRECIPITATION INTO NORTHEAST IOWA
AFTER MIDNIGHT SUNDAY NIGHT. BY FAR THE NAM IS THE FASTEST OF ANY
GUIDANCE AND THEREFORE FOR NOW HAS BEEN DISCOUNTED. HAVE DRIED OUT
ALMOST ALL OF THE FORECAST AREA AS A RESULT...THOUGH LEFT A 20
PERCENT CHANCE FOR CHARLES CITY TO OELWEIN IA JUST IN CASE THE
FASTER SCENARIO WOULD PLAY OUT. AN INCREASE IN MID TO UPPER LEVEL
CLOUD COVER IS LIKELY SUNDAY NIGHT...HOWEVER. A GRADUAL WARMING
TREND IS ANTICIPATED THROUGH THE WEEKEND AS THE ARCTIC HIGH SLOWLY
MODIFIES...HELPED TOO BY THE GENERAL LACK OF SNOW COVER FROM THE
DAKOTAS INTO THE UPPER MISSISSIPPI RIVER VALLEY. 850MB TEMPS CLIMB
TO -12C BY 00Z SUNDAY AND -6C BY 00Z MONDAY. WITH THE WARMING 850MB
TEMPS...HIGHS SHOULD CLIMB INTO THE 15 TO 20F RANGE ON SATURDAY AND
25 TO 30F RANGE ON SUNDAY.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
237 AM CST FRI FEB 10 2012
OVERALL PATTERN LOOKS FAIRLY BENIGN THROUGHOUT MUCH OF THE LONG TERM
PERIOD SUGGESTED BY THE 10.00Z ECMWF/CANADIAN/GFS/UKMET AND GFS
ENSEMBLES. A SPLIT FLOW SCENARIO IS FORECAST BY ALL OF THESE
MODELS...WITH THE NORTHERN STREAM FEATURING ZONAL TO WEAK TROUGHING
ACROSS SOUTHERN CANADA...AND A SOUTHERN STREAM FEATURING TROUGHING
IN THE SOUTHWEST U.S. TO ZONAL TO SLIGHT RIDGING OVER THE
SOUTHEASTERN U.S.. THIS MEANS MOST OF THE PRECIPITATION ACTION ENDS
UP STAYING TO THE NORTH AND SOUTH OF THE FORECAST AREA WITH NO COLD
SHOTS IN THE OFFERING. THE ONLY EXCEPTION TO THE PRECIPITATION IS
MONDAY INTO MONDAY EVENING...DUE TO THE COMBINATION OF WEAK LOW
LEVEL MOISTURE TRANSPORT AND WEAK SHORTWAVES PROGGED TO MOVE THROUGH
THE AREA. THESE SHORTWAVES ORIGINATING OUT OF THE TROUGHING MOVING
INTO THE PLAINS SUNDAY NIGHT. THERE REMAINS STRONG CONTINUITY FOR
PRECIPITATION SOUTH OF I-90...SO MAINTAINED 50-60 PERCENT CHANCES
THERE FOR MONDAY. PRECIPITATION CHANCES TAPER OFF HEADING NORTH AS
CONFIDENCE IN MOISTURE AVAILABILITY IS LOWER. DOES NOT LOOK LIKE
ANYTHING BIG IN TERMS OF SNOW ACCUMULATION GIVEN THE WEAK
FORCING...PERHAPS AROUND AN INCH. A LITTLE FARTHER OUT...THE 10.00Z
ECMWF/CANADIAN BOTH HINT AT SOME SHORTWAVE TROUGHS CROSSING THE AREA
WEDNESDAY NIGHT INTO THURSDAY...ORIGINATING FROM SOUTHERN EXTENSIONS
OFF THE NORTHERN STREAM. WITH LACK OF MOISTURE...KEPT THE CONSENSUS
15 TO 20 PERCENT CHANCES. WOULD NOT BE SURPRISED IF IT ENDS UP DRY.
TEMPERATURES THROUGHOUT THE LONG TERM PERIOD SHOULD END UP AT OR
ABOVE NORMAL DUE TO ALL THE COLD AIR BEING LOCKED BACK UP OVER
NORTHERN CANADA. IN FACT...IT APPEARS THE GENERAL ABOVE NORMAL
CONDITIONS WILL PERSIST AT LEAST FOR THE NEXT ONE TO TWO WEEKS...IF
NOT LONGER...PER THE CFS VERSION 2 FORECASTS.
&&
.AVIATION...THROUGH 18Z SATURDAY
1130 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUD HEIGHTS THIS AFTERNOON AND THEN
CLEARING TREND LATER TODAY. MVFR-VFR CEILINGS GENERALLY IN THE
025KFT-040KFT RANGE EXTEND ACROSS THE REGION LATE THIS MORNING AS
SHORTWAVE TROUGH IS DROPPING ACROSS THE REGION. MODELS ARE SHOWING
CEILINGS WILL REMAIN IN THE VFR CATEGORY THROUGH MUCH OF THE
AFTERNOON. THERE STILL COULD BE A FEW FLURRIES THROUGHOUT THE
AFTERNOON...BUT BETTER CHANCES WILL BE SOUTH OF THE TAF SITES AND
THUS WILL NOT INCLUDE IN THE 18Z TAFS. SOME BREAKS BEING SEEN IN
THE CLOUDS ACROSS NORTHERN WISCONSIN...AND WOULD EXPECT CEILINGS
TO BECOME BROKEN LATER THIS AFTERNOON BETWEEN 21Z-23Z....WITH
CLEAR SKIES AND VFR CONDITIONS THEN AFTER 01Z-02Z AND CONTINUING
THROUGH 18Z SATURDAY. NORTH WINDS WILL ALSO GUST TO 20 TO 25 KNOTS
MUCH OF THE AFTERNOON...WITH THE GUSTS DIMINISHING THIS
EVENING... THEN PICKING UP AGAIN AFTER 15Z SATURDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 AM CST FRI FEB 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
540 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
237 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUDS/TEMPERATURES/PRECIPITATION
TODAY...THEN WIND CHILLS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S INTO THE NORTHWEST
TERRITORIES OF CANADA...AND TROUGHING FROM THE DAKOTAS INTO QUEBEC.
WITHIN THIS TROUGH...A SHORTWAVE WAS PRESENT FROM NORTH DAKOTA INTO
NORTHERN MINNESOTA. A REMNANT STREAM OF PACIFIC MOISTURE AND DPVA
AHEAD OF THE SHORTWAVE HELPING TO PRODUCE A BAND OF MID-CLOUDS FROM
NORTHEAST SOUTH DAKOTA TO LAKE SUPERIOR. BELOW THIS...AN AREA OF
STRATUS RESULTING FROM MOISTURE TRAPPED IN A COLD FRONTAL INVERSION
WAS PRESENT FROM NORTHWEST IOWA INTO NORTHERN WISCONSIN. SOME LIGHT
SNOW WAS ALSO FALLING OUT OF THIS STRATUS OVER THE NORTH HALF OF
WISCONSIN...DUE TO THE PRESENCE OF LOW LEVEL FRONTOGENESIS PER RUC
ANALYSIS. THE THERMAL CONTRAST OF THE FRONTOGENESIS COULD BE SEEN
FROM A 00Z 850MB SOUNDING PLOT...NOTED BY A -6C TEMP AT MPX AND -17C
AT INL. AT THE SURFACE...A COLD FRONTAL BOUNDARY STRETCHED FROM
NORTHERN LAKE MICHIGAN SOUTHWEST TO DES MOINES...WHILE A 1041MB
ARCTIC HIGH PRESSURE AREA WAS OVER CENTRAL SASKATCHEWAN.
TODAY AND TONIGHT...SHORTWAVE OVER NORTH DAKOTA AND NORTHERN
MINNESOTA IS PROGGED TO MOVE THROUGH THE FORECAST AREA BETWEEN
15-21Z TODAY...ALLOWING THE ARCTIC HIGH PRESSURE AREA OVER
SASKATCHEWAN TO DROP SOUTH IN ITS WAKE. BY 12Z SATURDAY...THE HIGH
SHOULD BE SITUATED IN THE DAKOTAS. WITH THE HIGH WELL OFF TO THE
WEST...ANTICIPATING BLUSTERY CONDITIONS ACROSS MUCH OF THE FORECAST
AREA THROUGH TONIGHT. WIND DIRECTION IS A LITTLE INTERESTING. DUE TO
THE TRACK OF THE DEPARTING COLD FRONT...THE SURFACE-850MB WINDS ARE
MORE NORTH TO NORTHEAST TODAY...THEN SWITCHES TO THE NORTHWEST
TONIGHT. THIS WIND DIRECTION PATTERN MEANS THAT LOW LEVEL MOISTURE/
CLOUDS MAY GET STUCK OVER THE FORECAST AREA MORE TODAY...AIDED BY
MOISTENING OFF LAKE SUPERIOR. ONCE THE WINDS GO NORTHWEST...THE DRY
ARCTIC AIR CAN FLOW IN AND CLEAR OUT THE STRATUS. ONE CAVEAT IS THAT
RIGHT NOW THE AIR OVER NORTHERN ONTARIO IS DRIER THAN THE MODELS
SUGGEST. WILL HAVE TO WATCH TO SEE THROUGH THE DAY TODAY ON HOW MUCH
OF THIS DRIER AIR OVER NORTHERN ONTARIO ADVECTS SOUTH. NEXT CONCERN
IS THE PRECIPITATION. THE 10.00Z NAM AND HRRR RUNS HAVE SHOWN SOME
VERY LIGHT SNOW/FLURRIES...MOSTLY ALONG AND EAST OF THE MISSISSIPPI
RIVER THIS MORNING. LOW LEVEL FRONTOGENETICAL FORCING APPEARS TO BE
THE MAIN PRODUCTION FEATURE...WITH THE SNOW MORE LIKELY TO OCCUR DUE
TO THE STRATUS EVENTUALLY INTERSECTING THE DENDRITIC GROWTH ZONE AS
THE COLDER AIR MOVES IN. A FEW TENTHS SEEM POSSIBLE. HAVE LEFT SOME
FLURRIES IN FOR THE AFTERNOON TOO...BUT THINK THE BULK OF ANY
ACCUMULATING TYPE SNOW WOULD BE OFF TO THE EAST WHERE THE LOW LEVEL
FRONTOGENESIS IS EXPECTED. FINAL CONCERN IS TEMPERATURES. 850MB
TEMPS REALLY DROP TODAY...FROM -8C SOUTHEAST TO -16C NORTHWEST
ACROSS THE FORECAST AREA AT 12Z...TO BASICALLY AROUND -20C AT 00Z.
WITH STRATUS IN PLACE AND FALLING 850MB TEMPS...LOOK FOR SURFACE
TEMPERATURES TO SLOWLY FALL THROUGH THE DAY...DROPPING WIND CHILLS.
TONIGHT...THE TEMPERATURE FALL WILL MAINLY BE A RESULT OF ADVECTION
DUE TO BLUSTERY CONDITIONS KEEPING THE BOUNDARY LAYER MIXED.
STILL...LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO SUGGESTED BY
GUIDANCE AND THE PREVIOUS FORECAST SEEM REASONABLE. MAY NEED WIND
CHILL ADVISORIES FOR PORTIONS OF THE AREA VERY LATE...MOST LIKELY
TAYLOR AND CLARK ZONES. GIVEN SUCH A SMALL AREA AND MARGINAL WIND
CHILLS AT THAT...HELD OFF ON ISSUING AN ADVISORY AT THIS TIME.
SATURDAY THROUGH SUNDAY NIGHT...FAIRLY QUIET PERIOD EXPECTED AS
500MB HEIGHTS GRADUALLY BUILD. ARCTIC HIGH PRESSURE AREA NEVER
BUILDS OVER THE AREA...TRACKING MORE SOUTH TO THE LOWER MISSISSIPPI
RIVER VALLEY BY MID-DAY SUNDAY. THIS TRACK SHOULD KEEP CONDITIONS
FROM DECOUPLING SATURDAY NIGHT...PREVENTING ANY DRAMATIC TEMPERATURE
FALL FROM RADIATIONAL COOLING. ONLY REAL CONCERN IS SUNDAY NIGHT.
DURING THIS PERIOD...MODELS HAVE UPPER TROUGHING CROSSING THE
WESTERN U.S. TOWARDS THE PLAINS WITH RIDGING BUILDING UP TOWARDS THE
FORECAST AREA. 10.00Z NAM HINTS THAT A FEW WEAK SHORTWAVES MAY COME
OUT OF THE TROUGH AND APPROACH THE AREA BY 12Z MONDAY. WITH THESE
SHORTWAVES...THE NAM BRINGS SOME PRECIPITATION INTO NORTHEAST IOWA
AFTER MIDNIGHT SUNDAY NIGHT. BY FAR THE NAM IS THE FASTEST OF ANY
GUIDANCE AND THEREFORE FOR NOW HAS BEEN DISCOUNTED. HAVE DRIED OUT
ALMOST ALL OF THE FORECAST AREA AS A RESULT...THOUGH LEFT A 20
PERCENT CHANCE FOR CHARLES CITY TO OELWEIN IA JUST IN CASE THE
FASTER SCENARIO WOULD PLAY OUT. AN INCREASE IN MID TO UPPER LEVEL
CLOUD COVER IS LIKELY SUNDAY NIGHT...HOWEVER. A GRADUAL WARMING
TREND IS ANTICIPATED THROUGH THE WEEKEND AS THE ARCTIC HIGH SLOWLY
MODIFIES...HELPED TOO BY THE GENERAL LACK OF SNOW COVER FROM THE
DAKOTAS INTO THE UPPER MISSISSIPPI RIVER VALLEY. 850MB TEMPS CLIMB
TO -12C BY 00Z SUNDAY AND -6C BY 00Z MONDAY. WITH THE WARMING 850MB
TEMPS...HIGHS SHOULD CLIMB INTO THE 15 TO 20F RANGE ON SATURDAY AND
25 TO 30F RANGE ON SUNDAY.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
237 AM CST FRI FEB 10 2012
OVERALL PATTERN LOOKS FAIRLY BENIGN THROUGHOUT MUCH OF THE LONG TERM
PERIOD SUGGESTED BY THE 10.00Z ECMWF/CANADIAN/GFS/UKMET AND GFS
ENSEMBLES. A SPLIT FLOW SCENARIO IS FORECAST BY ALL OF THESE
MODELS...WITH THE NORTHERN STREAM FEATURING ZONAL TO WEAK TROUGHING
ACROSS SOUTHERN CANADA...AND A SOUTHERN STREAM FEATURING TROUGHING
IN THE SOUTHWEST U.S. TO ZONAL TO SLIGHT RIDGING OVER THE
SOUTHEASTERN U.S.. THIS MEANS MOST OF THE PRECIPITATION ACTION ENDS
UP STAYING TO THE NORTH AND SOUTH OF THE FORECAST AREA WITH NO COLD
SHOTS IN THE OFFERING. THE ONLY EXCEPTION TO THE PRECIPITATION IS
MONDAY INTO MONDAY EVENING...DUE TO THE COMBINATION OF WEAK LOW
LEVEL MOISTURE TRANSPORT AND WEAK SHORTWAVES PROGGED TO MOVE THROUGH
THE AREA. THESE SHORTWAVES ORIGINATING OUT OF THE TROUGHING MOVING
INTO THE PLAINS SUNDAY NIGHT. THERE REMAINS STRONG CONTINUITY FOR
PRECIPITATION SOUTH OF I-90...SO MAINTAINED 50-60 PERCENT CHANCES
THERE FOR MONDAY. PRECIPITATION CHANCES TAPER OFF HEADING NORTH AS
CONFIDENCE IN MOISTURE AVAILABILITY IS LOWER. DOES NOT LOOK LIKE
ANYTHING BIG IN TERMS OF SNOW ACCUMULATION GIVEN THE WEAK
FORCING...PERHAPS AROUND AN INCH. A LITTLE FARTHER OUT...THE 10.00Z
ECMWF/CANADIAN BOTH HINT AT SOME SHORTWAVE TROUGHS CROSSING THE AREA
WEDNESDAY NIGHT INTO THURSDAY...ORIGNIATING FROM SOUTHERN EXTENSIONS
OFF THE NORTHERN STREAM. WITH LACK OF MOISTURE...KEPT THE CONSENSUS
15 TO 20 PERCENT CHANCES. WOULD NOT BE SURPRISED IF IT ENDS UP DRY.
TEMPERATURES THROUGHOUT THE LONG TERM PERIOD SHOULD END UP AT OR
ABOVE NORMAL DUE TO ALL THE COLD AIR BEING LOCKED BACK UP OVER
NORTHERN CANADA. IN FACT...IT APPEARS THE GENERAL ABOVE NORMAL
CONDITIONS WILL PERSIST AT LEAST FOR THE NEXT ONE TO TWO WEEKS...IF
NOT LONGER...PER THE CFS VERSION 2 FORECASTS.
&&
.AVIATION...TODAY AND TONIGHT
531 AM CST FRI FEB 10 2012
THE 10.00Z AND 10.06Z MODELS CONTINUE TO SHOW THAT A MVRF AROUND
2K FEET WILL LINGER ACROSS THE AREA THROUGH EARLY THIS
AFTERNOON...AND THEN SLOWLY RISE INTO THE 3-5K FOOT RANGE BETWEEN
10.20Z AND 11.00Z. SKIES SHOULD RAPIDLY CLEAR BETWEEN 11.00Z AND
11.04Z.
NORTH WINDS WILL BE SUSTAINED IN THE 15 TO 25 KNOT RANGE WITH
OCCASIONAL WIND GUSTS UP TO 30 KNOTS TODAY. THE WINDS WILL SHIFT
TO NORTHWEST AND DECREASE TO 10 TO 20 KNOTS THIS EVENING. THESE
WINDS WILL THEN CONTINUE THROUGH THE OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 AM CST FRI FEB 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
252 AM CST FRI FEB 10 2012
.VERY SHORT TERM...TODAY AND TONIGHT.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE KENOSHA AREA AROUND NOON.
A MID LEVEL SHORTWAVE WILL DROP SOUTHEAST AND EXTEND ACROSS EASTERN
LAKE SUPERIOR TO FAR SOUTHERN MINNESOTA BY NOON AND PUSH ACROSS
SOUTHEAST WISCONSIN EARLY THIS AFTERNOON. THIS IS SLOWING THE
SOUTHWARD PROGRESSION OF THE FRONT AND ALSO CAUSING WEAK UPWARD
MOTION TO CONTINUE AFTER THE FRONTAL PASSAGE. FORECAST SOUNDINGS
SHOW MOISTURE EXTENDING FROM THE LOW LEVELS THROUGHOUT THE MID
LEVELS. MID LEVELS THEN DRY BEHIND THE 500 MB TROUGH AXIS. AS THIS
HAPPENS LOW LEVEL LAPSE RATES INCREASE TO ALMOST 9 C/KM FROM THE
SURFACE TO 850 MB. THEREFORE EXPECT AN INITIAL SNOW SHOWER
POTENTIAL WITH THE FRONT...BUT SOME LIGHT SNOW SHOWERS/FLURRIES WILL
CONTINUE ACROSS SOUTH CENTRAL WISCONSIN THIS AFTERNOON AND ACROSS
SOUTHEAST WISCONSIN INTO THE EARLY EVENING.
NEXT PROBLEM IS INITIAL LAKE ENHANCEMENT BEHIND THE FRONT. NAM
FORECAST SOUNDINGS GENERATE LAKE ENHANCEMENT WITH AROUND 200 J/KG
OF CAPE EARLY THIS AFTERNOON AND AROUND 300 J/KG LATE THIS AFTERNOON
AND 400 J/KG EARLY THIS EVENING. DELTA T VALUES ARE MARGINAL THIS
AFTERNOON BUT JUMP TO MODERATE THIS EVENING OF -17 C. NAM SOUNDING
INDICATE THAT BY THE TIME THIS HAPPENS WINDS BECOME NORTH ACROSS
MUCH OF THE LOW LEVELS EXCEPT NORTHEAST IN A NARROW LAYER AROUND 4
THSD FT. RUC SOUNDINGS ARE MORE FAVORABLE WITH NNE OR NE WINDS FROM
JUST ABOVE THE SURFACE TO ALMOST 7 THSD FT.
WILL HOLD OFF ON ANY HEADLINES DUE TO THE UNCERTAINTY...BUT WILL
BUMP UP THE SNOW AMOUNTS NEAR THE LAKE.
AFTER MIDNIGHT THE 500 MB TROUGH REACHES LOWER MICHIGAN...AND THE
SOUNDINGS NEAR LAKE MICHIGAN SHOW A PRONOUNCED DRYING ABOVE
3 THSD FT.
.SHORT TERM...SATURDAY THROUGH SUNDAY NIGHT.
SPRAWLING...SLOW MOVING HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS
TONIGHT AND SATURDAY AS COLD AIR SETTLES OVER THE REGION. CORE OF
COLDEST AIR WITH 85H TEMPS AROUND -18C SHIFTS SLOWLY EWD ON
SAT...CONTINUING ON SUN AS THE LOW LEVEL WINDS BEGIN TO BACK MORE
NORTHWEST. NEVERTHELESS...DESPITE SUNSHINE DO NOT WANT TO WARM TEMPS
TOO FAST AS BLUSTERY NORTHWEST WINDS WL CONTINUE ON SAT AT THE
SFC...AND SOME AREAS WL LIKELY HAVE A FRESH LIGHT SNOW COVER. MAY BE
ABLE TO MIX TO AROUND 925H BOTH DAYS. HENCE DESPITE COLD BIAS DUE
TO PERSISTENT LACK OF SNOW...WL KEEP HIGHS IN THE 15 TO 20 RANGE
MOST AREAS SAT...AND IN MID-UPR 20S SUN. BLUSTERY NORTHWEST WINDS
OF 15 TO 25KTS WL ADD A STRONG CHILL TO THE AIR ON SAT. WIND CHILLS
WILL DROP TO BTWN 5 AND 15 BLO ZERO EARLY SAT MRNG AND AGAIN LATE
SAT NGT/EARLY SUN MRNG.
PERIOD OF MID-HIGH LEVEL CLOUDS ASSOCD WITH SURGE OF WARM AIR
ADVECTION MAY BRUSH PORTIONS OF SRN WI SAT NGT...BUT MAJORITY OF
CLOUDS REMAIN NORTH.
.LONG TERM...MONDAY THROUGH THURSDAY.
EXTENDED GUIDANCE REMAINS IN REASONABLE AGREEMENT THROUGH EARLY
PERIODS. INCREASING SOUTHERLY WINDS ON THE BACKSIDE OF THE LARGE
HIGH PRESSURE AREA ALLOW MOISTURE TO INCREASE TO AROUND 0.4 INCH BY
LATER MONDAY. STRONGEST TEMP/MOISTURE ADVECTION HOWEVER REMAINS TO
THE SOUTH OF WI...HOWEVER ECMWF...GFS AND GEM-NHEM DO INCREASE
MOISTURE TO AT LEAST 10K FEET. ALTHOUGH FORCING REMAINS WEAK AS MID
LEVEL SHORT WAVE MOVES THROUGH MONDAY NIGHT...CONDENSATION PRESSURE
DEFICITS DECREASE TO LESS THAN 10MB ON MONDAY WITH WEAK ISENTROPIC
OMEGA. WITH SLR AROUND 15 TO 1...POSSIBLE FOR AN INCH OR TWO OF
SNOW MONDAY INTO MONDAY NIGHT. ENOUGH CONSISTENCY AND AGREEMENT TO
BUMP UP POPS TO LIKELY OVER MORE OF SRN WI MON AFTN CLOSER TO
STRONGER LOW LEVEL WEAK FORECING...AND IN THE SOUTHEAST MON NGT.
MID LEVEL WEAK WAVE STILL EXPECTED TO SLIDE OFF TO THE EAST BY
TUESDAY... HOWEVER PROGRESS HAS SLOWED A BIT AS SECONDARY WEAK WAVE
MOVES FROM THE UPPER MIDWEST INTO THE CENTRAL MS VALLEY. WL
CONTINUE DRYING TREND INTO TUE...BUT KEEP SCHC POPS IN THE FAR
SOUTHEAST TO REFLECT SLOWER MOVEMENT.
SEVERAL DAYS AGO...THOUGHT WE WERE HEADING TO A MORE UNSETTLED
PERIOD FOR LATER NEXT WEEK...AS MULTIPLE PIECES OF SHORT WAVE ENERGY
WERE EJECTED FROM PERSISTENT NRN PACIFIC LONG WAVE TROUGH INTO
CENTRAL CONUS. HOWEVER LAST DAY OR TWO...TREND HAS BEEN TOWARD
RETURN OF SPLIT FLOW ACROSS CONUS...WITH SRN STREAM REMAINING MORE
ACTIVE FROM TUE INTO THU. ECWMF FIRST TO PICK UP ON DRIER NRN
STREAM SIGNAL...AND LAST SEVERAL RUNS OF GFS NOW BACKING OFF ON
UNSETTLED MID-WEEK WX FOR UPPER MIDWEST. HPC ALSO TRENDING TOWARD
DRIER SOLUTION...FAVORING ECMWF OR ECMWF BLEND. FOR NOW...WL KEEP
POPS VERY LOW FOR LATE PDS WITH LOW CONFIDENCE. END RESULT...PALTRY
WINTER CONDITIONS TO CONTINUE.
&&
.AVIATION /12Z TAFS/...
SOUTHWEST FLOW AND TRAPPED LOW LEVEL MOISTURE BROUGHT MVFR STRATUS
ACROSS THE FORECAST AREA AND WILL PERSIST EARLY THIS MORNING.
A STRONG COLD FRONT WILL DROP SOUTH ACROSS SOUTHERN WISCONSIN THIS
MORNING AND REACH THE FAR SOUTHEAST TIP AROUND NOON. MAINLY CIGS
EXPECTED BEHIND THE FRONT ALONG WITH MVFR VSBYS IN SNOW SHOWERS WITH
SOME IFR VSBYS IN THE HEAVIER SNOW SHOWERS. APPEARS LAKE
ENHANCEMENT TO DEVELOP LATE THIS MORNING TOWARD SHEBOYGAN AND
ACROSS SOUTHEAST WISCONSIN FROM MILWAUKEE SOUTH THIS AFTERNOON.
OCCASIONAL IFR VSBYS EXPECTED WITH THIS SNOW. BY EVENING A LAKE
EFFECT SNOW BAND SHOULD SET UP MAINLY OVER WESTERN LAKE MICHIGAN AND
AFFECT AREAS MAINLY SOUTH OF THE ILLINOIS BORDER...BUT THERE IS A
POSSIBILITY OF SOME OF THIS SNOW AFFECTING THE SHORELINE AREAS
MAINLY SOUTH OF MILWAUKEE.
&&
.MARINE...
WINDS MAY BRIEFLY DROP BELOW SMALL CRAFT CRITERIA EARLY THIS MORNING
JUST AHEAD OF A TROUGH OF LOW PRESSURE EXTENDING ACROSS NORTHERN
LAKE MICHIGAN. AS AN ASSOCIATED STRONG COLD FRONT DROPS SOUTH
ACROSS SOUTHERN LAKE MICHIGAN LATER THIS MORNING WINDS WILL BECOME
NORTH AND INCREASE DRAMATICALLY. A FEW WIND GUSTS MAY APPROACH GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS.
DUE TO THE COLDER AIR WAVES EXPECTED TO INCREASE RAPIDLY BEHIND THE
FRONT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL OF THE SHORE
AREAS INTO SATURDAY AFTERNOON.
&&
.CONFIDENCE...
TODAY AND TONIGHT...MEDIUM.
SATURDAY THROUGH SUNDAY NIGHT...MEDIUM TO HIGH.
MONDAY AND MONDAY NIGHT...MEDIUM TO HIGH.
TUESDAY...MEDIUM.
WEDNESDAY AND THURSDAY...LOW TO MEDIUM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CST SATURDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL NOON CST SATURDAY FOR LMZ643-644.
&&
$$
SHORT TERM/LONG TERM...MBK
VERY SHORT TERM/AVIATION/MARINE...SJH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
237 AM CST FRI FEB 10 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
237 AM CST FRI FEB 10 2012
MAIN FORECAST CONCERN IS ON CLOUDS/TEMPERATURES/PRECIPITATION
TODAY...THEN WIND CHILLS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S INTO THE NORTHWEST
TERRITORIES OF CANADA...AND TROUGHING FROM THE DAKOTAS INTO QUEBEC.
WITHIN THIS TROUGH...A SHORTWAVE WAS PRESENT FROM NORTH DAKOTA INTO
NORTHERN MINNESOTA. A REMNANT STREAM OF PACIFIC MOISTURE AND DPVA
AHEAD OF THE SHORTWAVE HELPING TO PRODUCE A BAND OF MID-CLOUDS FROM
NORTHEAST SOUTH DAKOTA TO LAKE SUPERIOR. BELOW THIS...AN AREA OF
STRATUS RESULTING FROM MOISTURE TRAPPED IN A COLD FRONTAL INVERSION
WAS PRESENT FROM NORTHWEST IOWA INTO NORTHERN WISCONSIN. SOME LIGHT
SNOW WAS ALSO FALLING OUT OF THIS STRATUS OVER THE NORTH HALF OF
WISCONSIN...DUE TO THE PRESENCE OF LOW LEVEL FRONTOGENESIS PER RUC
ANALYSIS. THE THERMAL CONTRAST OF THE FRONTOGENESIS COULD BE SEEN
FROM A 00Z 850MB SOUNDING PLOT...NOTED BY A -6C TEMP AT MPX AND -17C
AT INL. AT THE SURFACE...A COLD FRONTAL BOUNDARY STRETCHED FROM
NORTHERN LAKE MICHIGAN SOUTHWEST TO DES MOINES...WHILE A 1041MB
ARCTIC HIGH PRESSURE AREA WAS OVER CENTRAL SASKATCHEWAN.
TODAY AND TONIGHT...SHORTWAVE OVER NORTH DAKOTA AND NORTHERN
MINNESOTA IS PROGGED TO MOVE THROUGH THE FORECAST AREA BETWEEN
15-21Z TODAY...ALLOWING THE ARCTIC HIGH PRESSURE AREA OVER
SASKATCHEWAN TO DROP SOUTH IN ITS WAKE. BY 12Z SATURDAY...THE HIGH
SHOULD BE SITUATED IN THE DAKOTAS. WITH THE HIGH WELL OFF TO THE
WEST...ANTICIPATING BLUSTERY CONDITIONS ACROSS MUCH OF THE FORECAST
AREA THROUGH TONIGHT. WIND DIRECTION IS A LITTLE INTERESTING. DUE TO
THE TRACK OF THE DEPARTING COLD FRONT...THE SURFACE-850MB WINDS ARE
MORE NORTH TO NORTHEAST TODAY...THEN SWITCHES TO THE NORTHWEST
TONIGHT. THIS WIND DIRECTION PATTERN MEANS THAT LOW LEVEL MOISTURE/
CLOUDS MAY GET STUCK OVER THE FORECAST AREA MORE TODAY...AIDED BY
MOISTENING OFF LAKE SUPERIOR. ONCE THE WINDS GO NORTHWEST...THE DRY
ARCTIC AIR CAN FLOW IN AND CLEAR OUT THE STRATUS. ONE CAVEAT IS THAT
RIGHT NOW THE AIR OVER NORTHERN ONTARIO IS DRIER THAN THE MODELS
SUGGEST. WILL HAVE TO WATCH TO SEE THROUGH THE DAY TODAY ON HOW MUCH
OF THIS DRIER AIR OVER NORTHERN ONTARIO ADVECTS SOUTH. NEXT CONCERN
IS THE PRECIPITATION. THE 10.00Z NAM AND HRRR RUNS HAVE SHOWN SOME
VERY LIGHT SNOW/FLURRIES...MOSTLY ALONG AND EAST OF THE MISSISSIPPI
RIVER THIS MORNING. LOW LEVEL FRONTOGENETICAL FORCING APPEARS TO BE
THE MAIN PRODUCTION FEATURE...WITH THE SNOW MORE LIKELY TO OCCUR DUE
TO THE STRATUS EVENTUALLY INTERSECTING THE DENDRITIC GROWTH ZONE AS
THE COLDER AIR MOVES IN. A FEW TENTHS SEEM POSSIBLE. HAVE LEFT SOME
FLURRIES IN FOR THE AFTERNOON TOO...BUT THINK THE BULK OF ANY
ACCUMULATING TYPE SNOW WOULD BE OFF TO THE EAST WHERE THE LOW LEVEL
FRONTOGENESIS IS EXPECTED. FINAL CONCERN IS TEMPERATURES. 850MB
TEMPS REALLY DROP TODAY...FROM -8C SOUTHEAST TO -16C NORTHWEST
ACROSS THE FORECAST AREA AT 12Z...TO BASICALLY AROUND -20C AT 00Z.
WITH STRATUS IN PLACE AND FALLING 850MB TEMPS...LOOK FOR SURFACE
TEMPERATURES TO SLOWLY FALL THROUGH THE DAY...DROPPING WIND CHILLS.
TONIGHT...THE TEMPERATURE FALL WILL MAINLY BE A RESULT OF ADVECTION
DUE TO BLUSTERY CONDITIONS KEEPING THE BOUNDARY LAYER MIXED.
STILL...LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO SUGGESTED BY
GUIDANCE AND THE PREVIOUS FORECAST SEEM REASONABLE. MAY NEED WIND
CHILL ADVISORIES FOR PORTIONS OF THE AREA VERY LATE...MOST LIKELY
TAYLOR AND CLARK ZONES. GIVEN SUCH A SMALL AREA AND MARGINAL WIND
CHILLS AT THAT...HELD OFF ON ISSUING AN ADVISORY AT THIS TIME.
SATURDAY THROUGH SUNDAY NIGHT...FAIRLY QUIET PERIOD EXPECTED AS
500MB HEIGHTS GRADUALLY BUILD. ARCTIC HIGH PRESSURE AREA NEVER
BUILDS OVER THE AREA...TRACKING MORE SOUTH TO THE LOWER MISSISSIPPI
RIVER VALLEY BY MID-DAY SUNDAY. THIS TRACK SHOULD KEEP CONDITIONS
FROM DECOUPLING SATURDAY NIGHT...PREVENTING ANY DRAMATIC TEMPERATURE
FALL FROM RADIATIONAL COOLING. ONLY REAL CONCERN IS SUNDAY NIGHT.
DURING THIS PERIOD...MODELS HAVE UPPER TROUGHING CROSSING THE
WESTERN U.S. TOWARDS THE PLAINS WITH RIDGING BUILDING UP TOWARDS THE
FORECAST AREA. 10.00Z NAM HINTS THAT A FEW WEAK SHORTWAVES MAY COME
OUT OF THE TROUGH AND APPROACH THE AREA BY 12Z MONDAY. WITH THESE
SHORTWAVES...THE NAM BRINGS SOME PRECIPITATION INTO NORTHEAST IOWA
AFTER MIDNIGHT SUNDAY NIGHT. BY FAR THE NAM IS THE FASTEST OF ANY
GUIDANCE AND THEREFORE FOR NOW HAS BEEN DISCOUNTED. HAVE DRIED OUT
ALMOST ALL OF THE FORECAST AREA AS A RESULT...THOUGH LEFT A 20
PERCENT CHANCE FOR CHARLES CITY TO OELWEIN IA JUST IN CASE THE
FASTER SCENARIO WOULD PLAY OUT. AN INCREASE IN MID TO UPPER LEVEL
CLOUD COVER IS LIKELY SUNDAY NIGHT...HOWEVER. A GRADUAL WARMING
TREND IS ANTICIPATED THROUGH THE WEEKEND AS THE ARCTIC HIGH SLOWLY
MODIFIES...HELPED TOO BY THE GENERAL LACK OF SNOW COVER FROM THE
DAKOTAS INTO THE UPPER MISSISSIPPI RIVER VALLEY. 850MB TEMPS CLIMB
TO -12C BY 00Z SUNDAY AND -6C BY 00Z MONDAY. WITH THE WARMING 850MB
TEMPS...HIGHS SHOULD CLIMB INTO THE 15 TO 20F RANGE ON SATURDAY AND
25 TO 30F RANGE ON SUNDAY.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
237 AM CST FRI FEB 10 2012
OVERALL PATTERN LOOKS FAIRLY BENIGN THROUGHOUT MUCH OF THE LONG TERM
PERIOD SUGGESTED BY THE 10.00Z ECMWF/CANADIAN/GFS/UKMET AND GFS
ENSEMBLES. A SPLIT FLOW SCENARIO IS FORECAST BY ALL OF THESE
MODELS...WITH THE NORTHERN STREAM FEATURING ZONAL TO WEAK TROUGHING
ACROSS SOUTHERN CANADA...AND A SOUTHERN STREAM FEATURING TROUGHING
IN THE SOUTHWEST U.S. TO ZONAL TO SLIGHT RIDGING OVER THE
SOUTHEASTERN U.S.. THIS MEANS MOST OF THE PRECIPITATION ACTION ENDS
UP STAYING TO THE NORTH AND SOUTH OF THE FORECAST AREA WITH NO COLD
SHOTS IN THE OFFERING. THE ONLY EXCEPTION TO THE PRECIPITATION IS
MONDAY INTO MONDAY EVENING...DUE TO THE COMBINATION OF WEAK LOW
LEVEL MOISTURE TRANSPORT AND WEAK SHORTWAVES PROGGED TO MOVE THROUGH
THE AREA. THESE SHORTWAVES ORIGINATING OUT OF THE TROUGHING MOVING
INTO THE PLAINS SUNDAY NIGHT. THERE REMAINS STRONG CONTINUITY FOR
PRECIPITATION SOUTH OF I-90...SO MAINTAINED 50-60 PERCENT CHANCES
THERE FOR MONDAY. PRECIPITATION CHANCES TAPER OFF HEADING NORTH AS
CONFIDENCE IN MOISTURE AVAILABILITY IS LOWER. DOES NOT LOOK LIKE
ANYTHING BIG IN TERMS OF SNOW ACCUMULATION GIVEN THE WEAK
FORCING...PERHAPS AROUND AN INCH. A LITTLE FARTHER OUT...THE 10.00Z
ECMWF/CANADIAN BOTH HINT AT SOME SHORTWAVE TROUGHS CROSSING THE AREA
WEDNESDAY NIGHT INTO THURSDAY...ORIGNIATING FROM SOUTHERN EXTENSIONS
OFF THE NORTHERN STREAM. WITH LACK OF MOISTURE...KEPT THE CONSENSUS
15 TO 20 PERCENT CHANCES. WOULD NOT BE SURPRISED IF IT ENDS UP DRY.
TEMPERATURES THROUGHOUT THE LONG TERM PERIOD SHOULD END UP AT OR
ABOVE NORMAL DUE TO ALL THE COLD AIR BEING LOCKED BACK UP OVER
NORTHERN CANADA. IN FACT...IT APPEARS THE GENERAL ABOVE NORMAL
CONDITIONS WILL PERSIST AT LEAST FOR THE NEXT ONE TO TWO WEEKS...IF
NOT LONGER...PER THE CFS VERSION 2 FORECASTS.
&&
.AVIATION...THROUGH 06Z SATURDAY
1110 PM CST THU FEB 9 2012
AN ARCTIC FRONT WILL CROSS THROUGH BOTH TAF SITES BETWEEN 06 AND 10Z
AND WINDS TAKE A TURN TO THE NORTHWEST...BECOMING GUSTY. SNOW
SHOWERS STILL LOOK POSSIBLE...AND CURRENT RADAR RETURNS SHOW BANDS
OF LIGHT SNOW MOVING SOUTHEAST ACROSS EASTERN MINNESOTA/NORTHWEST
WISCONSIN. SOME VSBY RESTRICTIONS IN THIS SNOW...BUT IF IT DOES
MANIFEST AT KRST/KLSE...DON/T EXPECT ANY REDUCTIONS BELOW 5SM AT
THIS TIME.
MOST FORECAST GUIDANCE CONTINUES TO SUGGEST A BROKEN TO OVERCAST
MVFR CEILINGS THROUGH MID DAY FRIDAY...GRADUALLY BECOMING SKC DURING
THE AFTERNOON. HOWEVER...LATEST NAM12/RUC13 850 MB RH AND WIND
FIELDS SHOW NORTH-NORTHEAST FLOW OFF LAKE SUPERIOR. THIS COULD LEAD
TO A LOBE OF LAKE ENHANCED STRATUS MOVING SOUTHWEST OVER KLSE AND
POSSIBLY KRST. CONFIDENCE IS NOT HIGH IN WHICH WAY THIS WILL
GO...BUT WILL LEAN ON DELAYING THE CLEARING UNTIL THE LATE
AFTERNOON/EVENING. OBVIOUSLY...TRENDS WILL BE MONITORED...AND IF
ADDITIONAL STRATUS DOES NOT DEVELOP...UPDATES FOR EARLIER CLEARING
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 AM CST FRI FEB 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION....TAYLOR/RIECK
AREA FORECAST DISCUSSION
NWS ALBANY NY
113 AM EST SUN FEB 12 2012
.SYNOPSIS...
ARCTIC AIR WILL CONTINUE TO MOVE INTO THE REGION THIS
MORNING. ANOTHER DISTURBANCE WILL MOVE SOUTH OF THE THE REGION
TODAY. AS IT MOVES ACROSS LAKE ONTARIO IT WILL TRIGGER LAKE EFFECT
SNOW IN PARTS OF THE REGION. HIGH PRESSURE WILL BUILD OVER THE
EASTERN HALF OF THE NATION MONDAY INTO TUESDAY. TEMPERATURES WILL
MODERATE AS THIS HIGH SLIDES OFFSHORE MIDWEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1 AM EST...SOME MINOR UPDATES TO NEAR TERM FORECAST.
OBSERVATIONS AND NEWEST NAM DATA WERE USED TO REFRESHEN HOURLY
T/TDS/RH AND APPRARENT TEMPS. THE BEST CHANCE TO HIT MARGINAL WIND
CHILL ADVISORY WILL BE IN THE SRN DACKS WITH VALUES AROUND -20F TO
-24F. IN THE SOUTHERN GREENS...IT WILL BE CLOSE WITH WIND CHILLS
IN THE HIGH PEAKS AROUND -20F. THE WINDS MAY KEEP THE TEMPS UP A
BIT IN THE VALLEYS. WE RAISED MIN TEMPS A FEW DEGREES IN THE MID
HUDSON REGION...AND CAPITAL REGION. ALSO...WE LOWERED THE POPS TO
BELOW 20 PERCENT WITH SCATTERED FLURRIES THIS MORNING FROM ALBANY
SOUTH AND WEST. SOME LAKE EFFECT SNOW SHOWERS MAY SNEAK IN TOWARDS
SUNRISE WEST OF THE HUDSON RIVER VALLEY IN THE NW FLOW...WITH
MULTIBANDS. THE BEST CHANCE OF A COATING TO AN INCH OR SO WILL BE
IN THE WRN MOHAWK VALLEY...AND ERN CATSKILLS. SKY GRIDS WERE ALSO
RETOOLED BASED ON THE 3.9-11 MICRON SATELLITE CURVE. IT WILL BE
COLD WITH H850 TEMPS APPROACHING -20F OVER THE NRN TIER...AS BRIEF
PERIOD OF ARCTIC AIR MOVES IN FOR THE FCST AREA.
PREVIOUS NEAR TERM...
AS OF 945 PM...TEMPERATURES CONTINUE TO DROP AND WINDS REMAIN
ELEVATED. PER THE LATEST LAMP/LAV GUIDANCE AND MESONET OBS...SEEMS
WE WILL HAVE WIND CHILL ISSUES FOR PORTIONS OF THE DACKS AND
SOUTHERN GREENS. WE WILL HOIST WIND CHILL ADVISORIES AT THIS TIME.
OTHERWISE...A COMBINATION OF SOME LOW STRATUS ACROSS THE HUDSON
RIVER VALLEY AND DEPARTING MID AND HIGH LEVEL MOISTURE ARE MAKING
FOR A CHALLENGING SKY FORECAST. STILL EXPECT SUBSIDENCE AND MIXING
TO REDUCE CLOUD COVER FURTHER BEFORE RETURNING LATE TONIGHT
DOWNWIND OF LAKE ONTARIO. HAVE LOWERED TEMPERATURES A COUPLE OF
DEGREES AND INCREASED WINDS SLIGHTLY.
AS OF 645 PM...A MESOSCALE FEATURE WAS ROTATING ACROSS THE SCHOHARIE
VALLEY AND TRACKING ACROSS THE EASTERN CATSKILLS THIS EARLY
EVENING. HRRR SEEMS TO HAVE A HINT OF THIS FEATURE AS IT SHOULD
CONTINUE TO TRACK SOUTHWARD AND WEAKEN TOWARD 03Z. EXPECTATIONS ARE
FOR A LULL IN THE PRECIP COVERAGE BETWEEN 03Z-09Z OVERNIGHT AS THE
COMBINATION OF THE DRIER AIR ADVECTING INTO THE REGION AND A BRIEF
WINDOW OF SUBSIDENCE. SO FOR THIS UPDATE...WE WILL CARRY POPS FOR
THE SOUTHERN 1/3RD OF NY COUNTIES THEN GO DRY FOR THAT PERIOD OF
03-09Z. PER THE LATEST NAM12/HRRR/RUC13...SEEMS THE BEST TRAJECTORY
FOR LAKE EFFECT SETS UP A LITTLE MORE NORTHWEST THAN PREVIOUS RUNS.
THIS WOULD LIMIT THE SNOW MIGRATING THROUGH THE MOHAWK VALLEY. WE
WILL AWAIT FOR THE 00Z GUIDANCE BEFORE MAKING ADDITIONAL
ENHANCEMENTS TO THE GRIDS/FORECAST.
&&
.SHORT TERM /6 AM SUNDAY THROUGH TUESDAY/... A FAIR AMOUNT OF
AGREEMENT AMONG GFS/NAM/CMC DURING THIS PERIOD. AT 500HPA CUT OFF
TROF IS LIFTING INTO N ATLC. RIDGE AXIS IS BUILDING FM SE USA TO N
GRT PLAINS. MODELS ALL SHOW A WK LK RESPONSE SIGNAL AS WHAT WAS A
CDFNT LIFTS BACK NE THROUGH RGN INTO QB MON. IT MAY FOCUS SOME
-SHSN INTO W FCA OR IS BEING ENHANCED BY WK WAA. BUT WITH
INVERSION HGT AT 5KFT NOT EXPECTING MUCH SUN NT IN WAY OF -SHSN.
MONDAY WITH 500HPA RIDGE AXIS TO OUR W...SFC HIGH SHIFTING TO EAST
COAST SHOULD BE A FAIR DAY WITH MODERATING TEMPS AFTER A COLD START.
MONDAY NT SFC HIGH SLIDES OFFSHORE AND 500HPA FLOW RETURNS TO A
ZONAL PATTERN WITH A FEW EMBEDDED WEAK SHORT WAVES.
A SERIES OF WEAK 500HPA SHORT WVS APPROACH LATE MON AND TUES WITH
INCRG CLOUDS TUES MORNING. MIDWEEK FINDS FCA IN ANOTHER MODIFIED
MARITIME POLAR AIR MASS THAT HAS TRAVELED ZONALLY ACROSS MUCH OF
THE USA. SFC HIGH OFFSHORE SETS UP SW FLOW W/FAIR AMOUNT OF
CLOUDINESS...AND MAYBE SOME LT PCPN OF VARIOUS FORMS MAINLY DZ OR
FZDZ IN THE EARLY MORNING HRS. NOT MUCH DYNAMICALLY GOING ON...JUST
CLOUDS STUCK UNDER INVERSIONS. TEMPS WELL ABV NORMALS AFTER A
CHILLY START MONDAY MORNING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
STILL A CHALLENGING LONG TERM PORTION OF THE FORECAST AS SEVERAL KEY
SHORT WAVES WERE SITUATED OVER THE NORTH PACIFIC THAT WILL HAVE
IMPLICATIONS FOR THE END OF NEXT WEEK.
WE BEGIN THIS LONG TERM FORECAST WITH A DEPARTING WAVE. MAINLY
CLOUDS ARE EXPECTED WITH THIS SYSTEM WITH GRADUAL IMPROVEMENTS
EXPECTED THROUGH THE DAY. EXCEPTION WOULD BE ACROSS THE HIGHER
TERRAIN AS MOIST LOW-MID LEVELS AND UPSLOPING CONDITIONS SHOULD
RESULT IN ENHANCED CLOUD COVER A BIT LONGER. BOUNDARY LAYER
TEMPERATURES ARE EXPECTED TO MODERATE SO ANY SNOW IN THE VALLEYS
SHOULD REDUCE.
THEN A RIDGE OF HIGH PRESSURE IS EXPECTED FROM LATE WEDNESDAY INTO
THURSDAY. THIS WILL KEEP OUR WEATHER TRANQUIL FOR THE MAJORITY OF
THE REGION. THE MINOR EXCEPTION TO THIS WOULD BE DOWNWIND OF LAKE
ONTARIO WHERE A WEAK THERMAL TROUGH MAY BE ENOUGH TO PRODUCE A MINOR
LAKE RESPONSE AND WILL KEEP POPS LOW AT THIS TIME. TEMPERATURES
DURING THIS TIME FRAME WILL AVERAGE A BIT ABOVE NORMAL FOR THIS TIME
OF THE YEAR.
THEN THE RATHER COMPLEX FORECAST FOR THURSDAY-FRIDAY TIME FRAME.
OUR POTENTIAL WAVE...PER THE 1.5PVU TRACE AND H2O VAPOR LOOP
ANALYSIS...WAS CURRENTLY TRACKING ALONG 45N AND JUST EAST OF 160W.
SATELLITE REPRESENTATION DOES SUGGEST THIS WAVE IS STRONG AS IT
RACES EAST TOWARD THE PACIFIC COASTLINE OF NOAM. NCEP MODEL SUITE
AN INTERNATIONAL GUIDANCE ALL OFFER A UNIQUE APPROACH THAT WILL HAVE
LARGE IMPLICATIONS ON OUR WEATHER. THE ECMWF WHICH HAS WAVERED A
BIT THE PAST SEVERAL RUNS...RETURNS WITH A RATHER STRONG SYSTEM
IMPACTING THE NORTHEAST. THE GFS REMAINS QUITE PROGRESSIVE AND
FAVORS A STRONGER HUDSON BAY LOW /AND A MORE POSITIVE NAO/. THE
CANADIAN TAKES THE STRONG BALANCE OF THESE AFOREMENTIONED FEATURES
WHICH SLOWS DOWN THE FORWARD PROGRESS OF THE PENDING EVENT BY ABOUT
1 DAY /ALSO A WARMER SOLUTION/. PLUMES/ENSEMBLES FROM THE GFS
REVEAL A CLUSTERING OF SOLUTIONS OF FURTHER SOUTHWARD TRACK AND MORE
PROGRESSIVE. ALTHOUGH WE CAN NOT RULE OUT THE ECMWF WHICH A COUPLE
OF THE GFS PERTURBATIONS DO AGREE WITH ITS OPERATIONAL SOLUTION. SO
A LOW CONFIDENCE FORECAST AT THIS TIME AND WILL KEEP POPS AROUND THE
30% THRESHOLDS WHICH IS IN AGREEMENT WITH HPC AND NEIGHBORING
FORECAST OFFICES. BOUNDARY LAYER TEMPS WILL ALSO BE TRICKY AS THE
RAIN/SNOW ISSUE IS EXPECTED TO BECOME A FACTOR AS WELL.
A CYCLONIC FLOW REGIME IS EXPECTED FOR THE START OF NEXT WEEKEND
WITH SOME SHOWER ACTIVITY AND PERHAPS SOME LAKE ONTARIO CONTRIBUTION
WHICH WILL BE HIGHLY DEPENDENT ON HOW MUCH COLD ADVECTION TAKES
PLACES IN THE WAKE OF THE THURSDAY-FRIDAY EVENT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
WILL HAVE CYCLONIC FLOW ACROSS THE REGION THROUGH THE TAF
PERIOD...06Z/MONDAY...WITH COLDER AIR BEING USHERED IN. CLOUD
COVER WILL CONTINUE TO DECREASE EARLY MORNING...HOWEVER CLOUDS
WILL INCREASE AFTER SUNRISE AS THE COLDER AIR PICKS UP MOISTURE
OFF THE GREAT LAKES. VFR CONDITIONS ARE EXPECTED. MVFR CLOUDS WILL
BE POSSIBLE AT KALB THIS EVENING AS THE FLOW COMES DOWN THE MOHAWK
VALLEY AND LOWER LAKE EFFECT CLOUDS MOVE INTO THE AREA. WINDS WILL
BE NORTHWESTERLY AND GUSTY TODAY ESPECIALLY AFTER SUNRISE AND
THROUGH THE AFTERNOON HOURS. WINDS SPEED WILL DECREASE THIS EVENING
WITH GUSTS HOLDING ON AT KALB.
OUTLOOK...
MON...VFR. BRISK WESTERLY WIND.
TUE-WED...VFR. SLIGHT CHC -SHSN/-SHRA
THU...VFR. CHC RAIN IN THE THE AFTN.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT SEVERAL DAYS. SOME
GAGES WILL CONTINUE TO BE IMPACTED BY ICE ACROSS NORTHERN PORTIONS
OF THE HYDROLOGIC SERVICE AREA.
COLDER AIR WILL BE USHERED IN THE REGION TONIGHT AND SHOULD LEAD
TO SOME ADDITIONAL ICE FORMATION ESPECIALLY ACROSS THE SOUTHERN
ADIRONDACKS...AND AREAS NORTH OF THE MOHAWK RIVER VALLEY.
HOWEVER...TEMPERATURES WILL MODERATE TO ABOVE NORMAL NEXT WEEK.
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...WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR NYZ032-033.
MA...NONE.
VT...WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR VTZ013-014.
&&
$$
SYNOPSIS...SNYDER/WASULA
NEAR TERM...BGM/WASULA
SHORT TERM...SNYDER
LONG TERM...BGM
AVIATION...IAA
HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS JACKSON MS
401 AM CST SUN FEB 12 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT...IT IS A CHILLY MORNING
ACROSS THE ARKLAMISS WITH TEMPERATURES IN THE 20S AREAWIDE. SOME
LOCATIONS HAVE BEEN ABLE TO DIP INTO THE LOWER 20S AND TEENS. A
BRISK NORTH WIND CONTINUES WHICH IS ALLOWING WIND CHILLS TO BE IN
THE TEENS AND LOWER 20S. COMPARED TO THIS TIME 24 HOURS AGO...WE ARE
ABOUT 15 TO 20 DEGREES COLDER. BASED ON RUC ANALYSIS...THE CENTER OF
THE SFC HIGH IS LOCATED JUST SOUTH OF TULSA BUT THE NORTH-SOUTH AXIS
OF THE SFC HIGH IS QUITE EXPANSIVE...RANGING FROM SOUTHERN CANADA TO
THE GULF OF MEXICO.
THE SFC HIGH WILL SHIFT ACROSS THE MID TO LOWER MISSISSIPPI VALLEY
REGION THROUGH THE DAY TODAY AND SHORTWAVE RIDGING WILL MOVE
OVERHEAD. THIS...COUPLED WITH THE PLENTY OF INSOLATION AND LESS
BRISK WINDS AS YESTERDAY...WE SHOULD WARM UP BETTER THAN YESTERDAY.
WHILE LOCATIONS GENERALLY ALONG AND SOUTH OF I-20 WERE ABLE TO REACH
INTO THE LOWER 40S YESTERDAY AFTERNOON...ALL LOCATIONS SHOULD BE
ABLE TO GET INTO THE 40S TODAY. AFTERNOON HIGHS EXPECTED TO RANGE
FROM THE LOWER 40S NORTH TO THE UPPER 40S/AROUND 50 SOUTH.
SOUTHERLY FLOW WILL RESUME BY THIS EVENING INTO TONIGHT...ALLOWING
FOR MOISTURE TO SLOWLY INCREASE BACK INTO THE REGION AND BEGIN SOME
WAA BACK INTO THE REGION. CLOUDS WILL SLOWLY MOVE BACK INTO THE
REGION AND OVERNIGHT LOWS WILL BE WARMING BUT WILL STILL BE ON THE
CHILLY SIDE AS THE COLDEST AIRMASS THIS YEAR DEPARTS. READINGS WILL
RANGE FROM THE UPPER 20S/LOWER 30S WEST TO A CHILLIER LOWER TO MID
20S IN THE EAST...CLOSEST TO THE SFC HIGH.
BY SUNRISE MONDAY...WE SHOULD BE FAIRLY WELL SHROUDED IN CLOUDS. IT
WILL BE SLOW TO WARM DUE TO THE EXTENSIVE CLOUD COVER BUT ALSO
PRECIP WILL BE DEVELOPING JUST TO THE WEST OF THE REGION. MODELS ARE
A LITTLE DIFFERENT IN THE TIMING OF THE ONSET OF PRECIP BUT
OVERALL...WE SHOULD BE SEEING SOME ONSET OF PRECIP BY MID MORNING.
THERE REMAINS SOME POTENTIAL FOR A WINTRY MIX OF PRECIP AT THE
ONSET. MODEL SOUNDINGS SHOW A MOIST LAYER IN THE MID LEVELS WITH
DRIER LOWER LEVELS. AS THE RAIN FALLS THROUGH THIS AND
EVAPORATES...THERE SHOULD BE SOME COOLING WHICH WILL ALLOW THE
PRECIP THAT REACHES THE GROUND TO BE A MIX OF LIGHT SNOW AND OR
LIGHT SLEET. AS THE MORNING WEARS ON INTO THE AFTERNOON...THIS
SHOULD BE MORE OF RAIN/SLEET MIX BEFORE THE ATMOSPHERE MOISTENS
THROUGHOUT THE COLUMN AND WARMS...THUS ENDING WITH ALL RAIN BY THE
AFTERNOON AND EVENING HOURS. THE MOST LIKELY LOCATIONS FOR WINTRY
MIX TO OCCUR WILL BE NORTH OF I-20. GIVEN THE WARMER GROUND TEMPS
AND LIGHT NATURE OF THIS PRECIP...NOT EXPECTING THIS TO ACCUMULATE
OR CAUSE TRAVEL OR ROAD ISSUES.
RAIN WILL CONTINUE MONDAY NIGHT AS THE UPPER TROUGH TRAVERSES NORTH
OF THE REGION. LIFT APPEARS TO BE JUST ENOUGH LATE MONDAY AFTERNOON
INTO THE EVENING FOR THERE TO BE PERHAPS TO BE SOME MODERATE RAIN
BUT OVERALL THE RAIN SHOULD TURN LIGHTER AS THE NIGHT PROGRESSES.
TEMPERATURES MONDAY NIGHT WILL REMAIN WARM ENOUGH TO DISMISS ANY
WINTRY PRECIP ISSUES WITH READINGS IN THE UPPER 30S TO LOWER/MID
40S.
MAIN ADJUSTMENTS TO THE GUI WERE TO CUT HIGH TEMPS MONDAY AS MAV GUI
CONTINUES TO COME IN ON THE HIGHER SIDE. GIVEN TOP DOWN MOISTENING
OF THE ATMOSPHERE...CLOUDS AND RAINFALL...CANT SEE TEMPS GETTING TOO
WARM. ALSO RAISED POPS IN THE DELTA FOR MONDAY AS THIS AREA LOOKS TO
BE MOST FAVORABLE FOR RAINFALL. /28/
.LONG TERM...TUESDAY THROUGH SUNDAY...THE FOCUS OF THIS PERIOD WILL
BE ON THE SYSTEM FOR MID WEEK WHICH WILL BRING RAIN/STORMS TO THE
REGION. OUTSIDE THAT...NO MAJOR TEMP SWINGS ARE EXPECTED WITH
GENERALLY CLIMO TYPE (OR SLGT ABV) CONDITIONS EXPECTED.
FOR TUE...LOOK FOR SOME LGT PRECIP LINGERING ACROSS THE E HALF TO
START THE PERIOD...BUT THIS WILL SHIFT EAST EARLY AND I EXPECT THE
PRECIP TO BE OUT OF THE AREA BY 9 AM. WHAT WILL LINGER MOST OF THE
DAY WILL BE LOW CLOUDS. LATEST GUID DATA INDICATES THIS AND THERE
WILL BE AN IMPACT ON TEMPS. THE GFS IS THE OUTLIER AND THE WARMEST
OF THE GUID. FOR THIS FORECAST...THE EURO/NAM TEMPS WERE USED. FOR
I-20 AND NORTH...52-60 DEGREES WILL BE THE RANGE. FURTHER
SOUTH...LESS CLOUD POTENTIAL WILL OFFER A BETTER OPPORTUNITY TO
WARM...HIGHS MAY PUSH 70 NEAR HBG.
FOR WED...THE ATMOSPHERE LOOKS TO TRANSITION QUICKLY TO A WAA REGIME
AND MOISTENING WILL OCCUR WITH RAIN/STORM DEVELOPING BY AFTERNOON
INTO WED NGT. THE EURO HAS BEEN VERY CONSISTENT WITH THIS SYSTEM
BOTH IN TIMING/INTENSITY. AT THIS TIME...NOT EXPECTING ANY SVR
WEATHER...BUT A FEW STRONG STORMS APPEAR POSSIBLE IF THE EURO
VERIFIES. THE GFS BRINGS PRECIP IN SLOWER...BUT MOVES THINGS OUT
QUICKER EARLY THU. THE GFS HAS LESS POTENTIAL FOR STRONG ACTIVITY
AND OFFERS MORE OF A RAIN/FEW TSRA SCENARIO. AS
MENTIONED...FOLLOWING THE EURO ON THIS ONE BUT WILL NOT MENTION ANY
STRONG STORM RISK AT THIS TIME DUE TO UNCERTAINTY BUT WE WILL KEEP
AN EYE ON ANY CHANGES AND ADD A RISK IF CONFIDENCE INCREASES.
TEMPS FOR WED WERE LOWERED MORE IN LINE WITH THE EURO/GFS ENSEMBLE
AS THE OPS GFS WAS THE HIGH MEMBER...MAINLY BECAUSE IT IS THE SLOWER
SOLUTION. ADDITIONALLY...LOW TEMPS WERE RAISED WED NGT AS HIGHER LOW
LEVEL MOISTURE WILL BE IN PLACE. I WAS CONSERVATIVE WITH LOWS THIS
PERIOD AND STAYED IN THE 50S. HOWEVER...IT COULD BE SEVERAL DEGREES
WARMER IF THE LOWER/MID 60 DEWPTS ARRIVE LIKE THE EURO SUGGESTS.
THE REST OF THE EXTENDED LOOKS TO GENERALLY BE QUIET...THERE ARE
DIFFERENCES IN THE GFS/EURO FOR SUNDAY. THE GFS IS WET WHILE THE
EURO DRY. FOR NOW...WILL JUST FOLLOW THE GFS...BUT I EXPECT THE EURO
TO BE MORE CORRECT. GUID TEMPS WERE FOLLOWED FOR THIS PERIOD AS
WELL. THE EXCEPTION WAS SAT MORNING. READINGS WERE WARMED TO MORE OF
A BLEND OF THE EURO/GFS ENSEMBLE. THE OPS GFS WAS ODDLY VERY COLD
AND LOWS WERE WARMED A DECENT AMOUNT. /CME/
&&
.AVIATION...HIGH CLOUDS STARTING TO STREAM INTO THE REGION AND THIS
WILL CONTINUE THROUGH THE DAY. VFR CONDITIONS EXPECTED TO CONTINUE
THROUGH TONIGHT. NORTH WINDS WILL CONTINUE BUT SPEEDS WILL BE AROUND
5-10KTS. CLOUD COVER WILL INCREASE AND LOWER FOR TONIGHT AS MOISTURE
INCREASES OVER THE AREA BUT CEILINGS EXPECTED TO REMAIN ABOVE 8KFT.
WINDS WILL SHIFT TONIGHT OUT OF THE SOUTHEAST AROUND 3-5KTS. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 46 25 51 41 / 0 6 56 86
MERIDIAN 47 22 52 41 / 0 3 36 86
VICKSBURG 45 27 50 42 / 0 11 76 82
HATTIESBURG 51 22 55 48 / 0 5 30 82
NATCHEZ 45 29 55 45 / 0 11 68 81
GREENVILLE 41 26 42 39 / 0 11 86 79
GREENWOOD 42 26 42 38 / 0 6 81 88
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
28/CME
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
206 AM CST SUN FEB 12 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
206 AM CST SUN FEB 12 2012
MAIN FORECAST CONCERN IS ON LIGHT SNOW FOR MONDAY INTO MONDAY
NIGHT
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER SOUTHWEST INTO SOUTH CENTRAL CANADA...AS WELL AS
OVER TEXAS INTO COLORADO...A SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST...A DEEPER SHORTWAVE TROUGH OVER THE DESERT SOUTHWEST...
AND A LONG-WAVE TROUGH ALONG THE EASTERN SEABOARD. WITH 500MB HEIGHTS
RISING OVER THE FORECAST AREA BEHIND THE LONG-WAVE TROUGH...WARMER
AIR ALOFT IS BEGINNING TO FLOW IN FROM CENTRAL CANADA. INTERESTING
THAT BETWEEN 00Z ON THE 10TH AND 00Z ON THE 12TH...850MB TEMPS HAVE
WARMED ABOUT 16C ACROSS MUCH OF CENTRAL CANADA PER 00Z RAOBS. IN
FACT...850MB TEMPS AT 00Z WERE -3C AT CHURCHILL MANITOBA...WARMER
THAN THE AVERAGE -13C OVER THE FORECAST AREA. AIRMASS REMAINS DRY
ACROSS THE ENTIRE UPPER MIDWEST...CENTRAL PLAINS AND UPPER
MISSISSIPPI RIVER VALLEY REGIONS...NOTED BY PRECIPITABLE WATER
VALUES BETWEEN 0.05-0.1 INCHES ON 00Z SOUNDINGS. THIS DRY AIR IS
ASSOCIATED WITH AN AREA OF HIGH PRESSURE AT THE SURFACE THAT
ENCOMPASSES ALL OF THE U.S. PLAINS. A SUSTAINED 5 TO 15 MPH
NORTHWEST WIND OVER THE FORECAST AREA...ON THE EAST SIDE OF HIGH...
HAS ONLY ALLOWED TEMPERATURES TO FALL INTO THE 8 TO 15F RANGE.
TODAY AND TONIGHT...THE UPPER RIDGING SEEN FROM TEXAS INTO COLORADO
IS PROGGED TO LIFT NORTHEAST TOWARDS THE AREA DURING THIS
PERIOD...IN RESPONSE TO THE TWO SHORTWAVE TROUGHS OUT WEST MOVING
OUT INTO THE WESTERN PLAINS. MOISTURE TRANSPORT OUT OF THE GULF OF
MEXICO AND DPVA AHEAD OF THESE TROUGHS SHOULD CAUSE PRECIPITATION TO
BREAK OUT ACROSS MUCH OF THE PLAINS TONIGHT...PERHAPS REACHING INTO
WESTERN IOWA LATE IN THE NIGHT. FOR OUR AREA...WE WILL REMAIN
INFLUENCED BY THE DRY AIR ASSOCIATED WITH THE SURFACE HIGH...AND ITS
RIDGE AXIS LOOKS TO CROSS TONIGHT. FULL SUN ANTICIPATED TODAY AND
WITH 850MB TEMPS PROGGED AROUND -6C AT 18Z...TEMPERATURES SHOULD
CLIMB INTO THE MID 20S TO NEAR 30. WILL STILL BE DEALING WITH A
NORTHWEST TO WESTERLY BREEZE...BUT IT DOES NOT LOOK AS BREEZY AS
YESTERDAY WITH A WEAKER PRESSURE GRADIENT PROGGED. THE WINDS MAY
HAVE A SHOT OF DECOUPLING TONIGHT...ESPECIALLY OVER WESTERN
WISCONSIN...SETTING UP BETTER RADIATIONAL COOLING. ON THE FLIP
SIDE...A WARMER DAY TODAY WILL PROBABLY END UP RESULTING IN LOWS
SIMILAR TO THOSE EXPERIENCED THIS MORNING. INCREASING MID/HIGH
CLOUDS LATER IN THE NIGHT WEST OF THE MISSISSIPPI RIVER SHOULD KEEP
TEMPERATURES A LITTLE WARMER THERE.
MONDAY AND MONDAY NIGHT...MODELS ARE IN GOOD AGREEMENT TAKING THE
TROUGHING OVER THE WESTERN PLAINS AT 12Z MONDAY MOSTLY INTO THE OHIO
VALLEY REGION MONDAY NIGHT. THERE IS A NORTHERN EXTENSION THAT
CROSSES THE FORECAST AREA LATE MONDAY INTO THE EARLY OVERNIGHT HOURS
MONDAY NIGHT. WITH THE BULK OF THE TROUGH HEADING MORE TO THE
SOUTH...THERE IS CONCERN ON HOW MUCH MOISTURE CAN MAKE IT NORTH INTO
THE FORECAST AREA. CERTAINLY MODELS SUGGEST IT HAPPENS ENOUGH TO
PRODUCE SOME LIGHT QPF ACROSS MUCH OF THE FORECAST AREA...THOUGH THE
BEST MOISTURE TRANSPORT AND ISENTROPIC LIFT STAYS TO THE SOUTH AND
EAST. SO BASICALLY THE HEIGHT FALLS AND DPVA FROM THE NORTHERN
EXTENSION OF THE TROUGH WILL BE THE MAIN FORCING FUNCTION FOR THE
PRECIPITATION. LOOKS LIKE PRECIPITATION SHOULD SLOWLY WORK SOUTHWEST
TO NORTHEAST ACROSS THE AREA ON MONDAY...WITH THE LINGERING DRY AIR
THE MAIN REASON FOR THE SLOW ADVANCEMENT. PRECIPITATION THEN
DIMINISHES WEST TO EAST AFTER MIDNIGHT MONDAY NIGHT AS THE TROUGH
PUSHES EAST. GOOD MODEL AGREEMENT REMAINS ON THIS LIGHT
PRECIPITATION EVENT...SO HAVING THE HIGH PRECIPITATION CHANCES AS
INDICATED BY THE PREVIOUS FORECAST SEEM REASONABLE. ONLY SLIGHT
UPWARD MODIFICATIONS WERE MADE. WITH RESPECT TO AMOUNTS...THINK THE
12.00Z NAM IS A LITTLE TOO HIGH ON QPF GIVEN WEAK FORCING OVERALL.
SHOULD MAINLY BE A 0.5 TO 1.5 INCH SNOW EVENT...WITH PERHAPS A
FEW TOTALS SLIGHTLY HIGHER THAN THAT. WITH A FLOW OF WARMER AIR
COMING IN WITH THE TROUGH...SLIGHTLY HIGHER HIGHS ARE ANTICIPATED
FOR MONDAY COMPARED TO TODAY. IN FACT...AREAS ACROSS WISCONSIN
COULD EVEN SEE SOME SUN IN THE MORNING. CLOUDY SKIES ARE EXPECTED
ACROSS THE AREA MONDAY NIGHT...AND WITH LITTLE OR NO COLD
ADVECTION...TEMPERATURES SHOULD ONLY DROP MAYBE 5 DEGREES FOR
LOWS.
TUESDAY AND TUESDAY NIGHT...IN THE WAKE OF THE MONDAY/MONDAY
TROUGH...MODELS SHOW ONE MORE SHORTWAVE MOVING WEST TO EAST ACROSS
THE FORECAST AREA LATE TUESDAY. APPEARS THIS SHORTWAVE WILL NOT HAVE
MUCH MOISTURE OR EVEN PRODUCE MUCH FORCING...THEREFORE HAVE DRY
CONDITIONS FOR TUESDAY. ON TUESDAY NIGHT...TROUGHING IS FORECAST TO
DROP DOWN INTO MANITOBA WHILE TROUGHING IS SHOWN AGAIN OVER THE
SOUTHWESTERN U.S.. HOWEVER...NEITHER FEATURE IS CLOSE ENOUGH TO
BRING ANY PRECIPITATION TO THE AREA. IN FACT...THERE SHOULD BE SOME
SLIGHT 500MB HEIGHT RISES TAKING PLACE. THEREFORE...DRY CONDITIONS
CONTINUE. 850MB TEMPS PROGGED AROUND -6C ON TUESDAY COMBINED WITH
SOME SLOW CLEARING AND A WARMER START WILL ALLOW FOR HIGHS A FEW
DEGREES WARMER THAN MONDAY. A LITTLE BETTER NIGHT INDICATED FOR
RADIATIONAL COOLING TUESDAY NIGHT WITH LIGHT WINDS...THOUGH THE
AIRMASS OVERALL IS RELATIVELY SPEAKING WARM WITH 850MB TEMPS HOLDING
NEARLY STEADY. IN ADDITION...THERE ARE HINTS OF SOME STRATUS TO MOVE
IN LATER IN THE NIGHT. FOR NOW...FOLLOWED A BLEND OF GUIDANCE FOR
LOWS.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
206 AM CST SUN FEB 12 2012
12.00Z MODELS (ECMWF/CANADIAN/UKMET/GFS/GFS ENSEMBLES) DEPICT A
MESSY UPPER LEVEL FLOW PATTERN THROUGHOUT THE LONG TERM...RESULTING
IN QUITE A FEW DIFFERENCES BETWEEN ALL THE MODELS. IT APPEARS THIS
IS A RESULT OF A FAST...ZONAL FLOW ACROSS THE PACIFIC RUNNING INTO
SPLIT FLOW OVER THE U.S. AND SOUTHERN CANADA. DESPITE THE
DIFFERENCES OF HANDLING SHORTWAVES...IN GENERAL THE LONG TERM PERIOD
LOOKS PRETTY QUIET WITH ALL OF THE COLD...ARCTIC AIR BEING LOCKED UP
OVER VERY FAR NORTHERN CANADA. THERE ARE A FEW FEATURES THAT MODELS
AGREE UPON AND WILL DISCUSS THEM HERE. THE FIRST IS THE TROUGHING
THAT DEVELOPS OVER THE SOUTHWESTERN U.S. TUESDAY NIGHT. 12.00Z
ECMWF/GFS/UKMET ARE ALL IN AGREEMENT ON SHEARING THIS TROUGH OUT AND
TRACKING IT THROUGH THE OHIO VALLEY ON THURSDAY. THIS TRACK AND
GIVEN THE FACT THAT IS SHEARING WOULD KEEP THE BULK OF THE
PRECIPITATION SOUTH OF THE FORECAST AREA...OR PERHAPS CLIP NORTHEAST
IOWA AND FAR SOUTHWEST WISCONSIN. THE 12.00Z CANADIAN IS THE ONLY
MODEL NOW STILL SUGGESTING A FARTHER NORTH...MORE PHASED LOOK...
WHICH RESULTS IN A DEEPER SYSTEM SPREADING PRECIPITATION OVER MUCH
OF THE AREA WEDNESDAY NIGHT INTO THURSDAY. HAVE LOWERED
PRECIPITATION CHANCES SOME DURING THIS PERIOD GIVEN THE TREND TO THE
UN-PHASED LOOK...AND STILL WOULD NOT BE SURPRISED IF IT ENDS UP DRY
LIKE THE 12.00Z GFS SHOWS. UPPER LEVEL TROUGHING DOES DEVELOP OVER
THE UPPER MISSISSIPPI RIVER VALLEY REGION EASTWARD INTO NEW ENGLAND
FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT. 850MB TEMPS ARE ONLY AROUND
-4C IN THE TROUGH SO AGAIN...NOTHING THAT COLD. FLOW THEN TURNS MORE
ZONAL FOR SATURDAY OVER THE AREA WITH NO PRECIPITATION SEEN. SO
OUTSIDE OF THE WEDNESDAY NIGHT/THURSDAY TIME PERIOD...A DRY LONG
TERM FORECAST IS EXPECTED. NO BIG WARM-UPS PLANNED EITHER.
HOWEVER...GIVEN 850MB TEMPS STAYING MOSTLY BETWEEN -4C AND 1C...
SURFACE TEMPERATURES SHOULD AT LEAST END UP 5-10 DEGREES NORMAL FOR
BOTH HIGHS AND LOWS. LOOKING FARTHER OUT INTO EARLY NEXT
WEEK...STILL NO SUGGESTIONS OF ANY MAJOR COOL DOWNS AS THE FAST
PACIFIC FLOW CONTINUES...ALLOWING PACIFIC AIR TO CONTINUE TO FLOW
ACROSS THE U.S.
&&
.AVIATION...THROUGH 06Z MONDAY
1055 PM CST SAT FEB 11 2012
HIGH PRESSURE WILL REMAIN THE MAIN WEATHER FEATURE THROUGH
SUNDAY...SHIFTING SOUTHEAST TO THE GULF STATES BY 06Z MON. WITH THE
CENTER OF THE HIGH STAYING JUST WEST AND SOUTH...THERE WILL BE A
PRESSURE GRADIENT KEEPING THE WINDS UP. EXPECT NORTHWEST-WEST WINDS
AROUND 10 KTS...BECOMING MORE SOUTHWEST-SOUTH SUNDAY NIGHT.
OTHERWISE...LOOK FOR MOSTLY CLEAR/VFR CONDITIONS.
SOME CLOUDS WILL BE ON THE RETURN OVERNIGHT SUNDAY AS AN UPPER LEVEL
TROUGH APPROACHES FROM THE PLAINS. CIGS WILL LOWER MONDAY...LIKELY
MVFR...WITH -SN ALSO MOVING IN. LOOK FOR VSBY RESTRICTIONS WITH THE
-SN WITH ACCUMULATIONS UP TO AN INCH POSSIBLE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
206 AM CST SUN FEB 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1007 AM EST SUN FEB 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE REGION THIS AFTERNOON THROUGH
MONDAY. AN UPPER LEVEL DISTURBANCE COULD BRING PRECIPITATION TO
THE REGION LATE MONDAY NIGHT AND ON TUE. ANOTHER DISTURBANCE COULD
BRING PRECIPITATION TO THE REGION ON THURDAY...THEN A COLD FRONT
WILL FOLLOW BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
DEPP UPPER LEVEL TROUGH HAS MOVED OFF THE EASTERN SEABOARD THIS
MORNING. TIGHT PRESSURE GRADIENT FROM DEEP SURFACE LOW IN THE
CANADIAN MARITIMES COUPLED WITH HIGH PRESSURE OVER THE SRN PLAINS
AND LOWER MS VALLEY WILL KEEP GUSTING NW WINDS ACROSS THE REGION
TODAY. FORECAST TEMPERATURES ARE WELL BELOW NORMAL FOR THE FIRST
TIME IN A LONG TIME...MORE IN LINE WITH A TYPICAL FEB WINTER DAY.
UPSLOPE SNOW CONDITIONS CONTINUE IN THE FAR WESTERN ZNS...ALTHOUGH
SURFACE WINDS BECOMING MORE SW ARE NOT CONDUCIVE TO DECENT
UPSLOPE. DOT CAMERAS AND OTHER WEB IMAGES SHOW LOW VSBYS NEAR
UPSLOPE REGION. WILL KEEP WINTER STORM WARNING GOING FOR NOW. HI
RES 3/4 KM MODELS KEEP UPSLOPE SNOW GOING THROUGH THIS AFTERNOON.
LATEST SOUNDINGS SHOW LOWERING OF THE INVERSION HEIGHT AT PIE/EKN
SITES DURING THE MID- LATE AFTERNOON HOURS...INDICATIVE OF SNOW
TAPERING OFF.
TEMPS SLOWLY RISING ACROSS THE REGION. 12Z/IAD SOUNDING SHOWED 850
HPA TEMPERATURE OF -18.1C. LOCAL STUDY SHOWS WHEN THE 12Z/IAD
SOUNDING IS -18...OBS SFC TEMPS NEVER MAKE IT OUT OF THE MID 30S.
MADE SOME TWEEKS TO THE TEMPS FOR THIS AFTERNOON BASED ON RAOB.
CANCELLED THE WIND CHILL ADVISORY FOR THE FAR WESTERN ZNS AS WINDS
HAVE ABATED SOMEWHAT AS TEMPS SLOWLY RISE OUT THERE.
ADJUSTED SKY COVER GRIDS BASED ON COMBINATION OF LATEST SAT AND
12KM RUC FORECASTS.
PREVIOUS DISCUSSIONS FOLLOWS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
MONDAY...A HIGH PRESSURE CENTER CROSSES THE SERN CONUS AS THE UPPER
TROUGH OVER THE ERN CONUS LIFTS NORTH. WARMING TREND BEGINS AS THE
NORTHERN STREAM LOSES INFLUENCE OVER THE MID ATLANTIC. MAX TEMPS LOW
TO MID 40S IN DOWNSLOPING WLY FLOW /STILL GUSTY TO AROUND 25 MPH IN
THE MORNING/. MOSTLY SUNNY IN THE MORNING...WITH HIGH CLOUDS
THICKENING THROUGH THE AFTERNOON FROM THE WEST.
MONDAY NIGHT...WITH INCREASING CLOUDS AHEAD OF A SHORTWAVE AND SWLY
FLOW...WENT ABOVE MEX GUIDANCE FOR MINS...UPR 20S TO AROUND 30F
INLAND...LOW 30S I-95 AND EAST.
TUESDAY...UPPER SHORTWAVE TROUGH PASSES FROM THE WEST WITH PASSING
SHOWERS. SNOW POSSIBLE UP ON THE RIDGES...OTHERWISE PROFILES ARE
WARM ENOUGH FOR RAIN. MAX TEMPS MID TO UPR 40S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND CONTINUED WARMING THROUGH THE MIDDLE PART OF THE
WEEK. MAX TEMPS INTO THE 50S FOR WEDNESDAY AND THURSDAY.
00Z GFS/ECMWF CONSENSUS ON THE SFC LOW OF A SYSTEM PASSING LATE
THURSDAY TO BE NORTH OF LWX. THEREFORE...CURRENT EXPECTATION IS FOR
RAIN. WILL NEED TO MONITOR THIS LOW AS IT PASSES.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS EXPECTED TODAY. WINDS GUSTING TO 30 KT AT TIMES
FROM 290-320. WINDS GRADUALLY BECOME MORE WESTERLY BY EARLY
EVENING BUT CONTINUED GUSTY. THERE IS A POTENTIAL FOR DECOUPLING
OF THE WINDS THIS EVENING.
VFR MONDAY/MONDAY NIGHT AS GUSTY NWLY FLOW SLOWLY SLACKENS AND
BECOME WLY AS HIGH PRESSURE PASSES TO THE SOUTH. PASSING RAIN
SHOWERS TUESDAY/TUESDAY NIGHT FROM A WEAK UPPER TROUGH...BEFORE MORE
HIGH PRESSURE THROUGH MIDWEEK. A STRONGER STORM SYSTEM LOOKS TO
CROSS THE MID ATLANTIC LATE THURSDAY.
&&
.MARINE...
WILL KEEP WNWLY GALES ACROSS THE WATERS TODAY. MODEL GUIDANCE
CONSENSUS OVERNIGHT WAS FOR A LULL IN GALES UNTIL THE LATE
AFTERNOON/EVENING BEFORE ANOTHER ROUND OF GALES THIS EVENING. WILL
CONTINUE TO EVALUATE THIS THINKING BUT WILL LEAVE IT UP FOR NOW
UNTIL NEW GUIDANCE SAYS OTHERWISE. THEN SMALL CRAFT ADVISORIES
ARE IN EFFECT THROUGH MONDAY MORNING AS HIGH PRESSURE BUILDS TO
THE SOUTH.
A WEAK UPPER TROUGH MOVES THROUGH TUESDAY...BRINGING RAIN SHOWERS TO
THE CHESAPEAKE BAY REGION AND SLY FLOW AROUND 15 KT /MAY SEE SOME
GUSTS AROUND 18 KT/. MORE HIGH PRESSURE AROUND MID WEEK. THE NEXT
STORM SYSTEM THEN CROSSES THE WATERS LATE THURSDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MDZ501.
VA...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR VAZ503.
WV...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR WVZ501-
503-505.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST MONDAY
FOR ANZ530>543.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR ANZ530>543.
&&
$$
SYNOPSIS...SMZ
NEAR TERM...SMZ
SHORT TERM...BAJ
LONG TERM...BAJ/NWL
AVIATION...SMZ
MARINE...SMZ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
911 AM EST SUN FEB 12 2012
.SYNOPSIS...
COLD BLUSTERY WESTERLY WINDS WILL MAINTAIN SNOW SHOWERS AND
BLOWING SNOW ACROSS THE UPPER OHIO VALLEY TODAY. MIDWEST HIGH PRESSURE
WILL PROVIDE MODERATING TEMPERATURES AND DRY WEATHER MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER BLEND OF RECENT SURFACE AND RADAR DATA, COUPLED WITH RECENT
HRRR MODEL OUTPUT, EXPECT A PASSING TROUGH ALOFT TO MAINTAIN NUMEROUS
SNOW SHOWERS AND AREAS OF BLOWING SNOW EAST OF I-77 CORRIDOR INTO
EARLY AFTERNOON. NAM MODEL PROFILES SHOW A LOWERING SUBSIDENCE
INVERSION THIS AFTERNOON, WHICH SHOULD CAP THE LAKE-MOISTURE-
ENHANCED INSTABILITY, AND WEAKEN THE SNOW SHOWERS DURING THE
AFTERNOON. HRRR AND WRF-NMM SIMULATED RADAR OUTPUT LIKEWISE SHOWS
A MARKED DECREASE IN SNOW SHOWER COVERAGE BY LATE AFTERNOON.
ITS HARD TO JUDGE HOW MUCH ADDITIONAL SNOW ACCUMULATION DUE TO THE
WIND AND BLOWING SNOW, BUT GENERALLY EXPECT 1 INCH ADDITIONAL
SNOWFALL TODAY, WITH UP TO 3 INCHES ACROSS THE HIGHER MOUNTAINS.
HENCE WILL MAINTAIN THE CURRENT WINTER WEATHER HEADLINES THROUGH
MIDDAY.
SPECIFIC TEMPERATURES, WINDS, AND GUSTS WERE BASED ON BLEND OF
RECENT GFS LAMP, HRRR, AND NAM MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
PER NAM MODEL OUTPUT, EXPECT THE CAPPING SUBSIDENCE INVERSION TO
FURTHER LOWER AND STRENGTHEN TONIGHT, ENDING THE SNOW SHOWERS AND
DECREASING CLOUD COVER. RADIATIONAL COOLING OVER THE FRESH SNOW
PACK WILL PROVIDE LOW TEMPERATURES TONIGHT SIMILAR TO SATURDAY
NIGHT.
AS HIGH PRESSURE BUILDS EAST FROM THE MIDWEST, EXPECT WARMER
TEMPERATURES ALOFT TO HELP BOOST AFTERNOON SURFACE TEMPERATURES TO
YIELD HIGHS CLOSE TO THE FREEZING MARK MONDAY AFTERNOON.
MODELS THEN SHOW A WEAK LOW PRESSURE SYSTEM, COMING EAST FROM THE
PLAINS TO PROVIDE SNOW SHOWERS TUESDAY, WITH TEMPERATURES TUESDAY
AFTERNOON MILDER THEN PREVIOUS DAYS BUT STILL ABOUT 5 DEGREES
COLDER THAN NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GENERALLY FOLLOWED EC AND HPC GUIDANCE. HIGH PRESSURE ACROSS REGION
WEDNESDAY WITH FAIR WEATHER. MODELS CONTINUE TO STRUGGLE WITH
STRENGTH OF LOW PRESSURE MOVING THROUGH OHIO RIVER VALLEY ON
THURSDAY...BUT EXPECT MOSTLY RAIN ON THURSDAY WITH SOME SNOW
POSSIBLE ACROSS FAR NORTH. BY FRIDAY SYSTEM IS WELL EAST OF AREA
WITH CHANCE OF SNOW SHOWERS IN NORTHWEST FLOW. HIGH PRESSURE
REMAINS WEST OF REGION WITH NORTHWEST FLOW. THIS SHOULD KEEP SOME
CLOUDINESS OF REGION...BUT LACK OF COLD AIR PRECLUDES SNOW SHOWER
ACTIVITY SATURDAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
NW FLOW ACROSS THE GREAT LAKES WILL CONTINUE TO GENERATE MVFR
STRATOCUMULUS AND SNOW SHOWERS OVER THE REGION TODAY. A SHORT WAVE
TROUGH WILL CROSS THE REGION LATE THIS MORNING...PROVIDING EXTRA
LIFT AND MOISTURE TO ENHANCE LAKE EFFECT SNOW SHOWERS. IFR
RESTRICTIONS CAN BE EXPECTED IN HEAVIER SNOW SHOWERS MAINLY AT
WESTERN PA TERMINALS THROUGH MIDDAY. SURFACE WINDS WILL GUST TO 25
KT AT TIMES CAUSING BLOWING SNOW.
DURING THE AFTERNOON...LOWERING SUBSIDENCE INVERSION WILL LIMIT THE
MIXING LAYER...BUT CONVECTION SHOULD STILL GENERATE SOME MVFR
CEILINGS FOR MOST TERMINALS. OVERALL IMPROVEMENT TO VFR CONDITIONS
AND REDUCED WIND GUSTS CAN BE EXPECTED BY LATE AFTERNOON.
OUTLOOK...MONDAY THROUGH THURSDAY...
BUILDING HIGH PRESSURE WILL RETURN VFR CONDITIONS FOR MONDAY.
A SHORTWAVE IN ZONAL FLOW IS PROGGED TO GENERATE MORE LIGHT SNOW BY
EARLY TUESDAY. MVFR RESTRICTIONS CAN BE EXPECTED WITH THAT SYSTEM.
REBUILDING HIGH PRESSURE WILL BRING A BRIEF RETURN TO VFR FOR
MIDWEEK. A STRONGER LOW IS PROGGED TO MOVE TOWARD THE REGION ON
THURSDAY AND WILL GENERATE THE POTENTIAL FOR RESTRICTIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MDZ001.
WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
PAZ007>009-013>016-020>023-073-075.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR PAZ074-
076.
WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR PAZ074-076.
WV...WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR WVZ023-
041.
WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION...UPDATE
NWS JACKSON MS
915 AM CST SUN FEB 12 2012
.UPDATE...CHILLY HIGH PRESSURE CENTERED RIGHT ACROSS THE MIDDLE AND
LOWER MISSISSIPPI VALLEYS TODAY WILL WORK TO HOLD BACK MOST OF THE
ENCROACHING CLOUDS AHEAD OF THE NEXT SYSTEM UNTIL TONIGHT. GENERALLY
LIGHT NORTH TO NORTHEAST WINDS WILL PREVAIL TODAY...WHICH IS GOOD
CONSIDERING THE VERY DRY AIR MASS MIGHT OTHERWISE PROMOTE AN
ELEVATED FIRE DANGER IF THE WINDS WERE ON PAR WITH YESTERDAY.
TEMPERATURES AT 9 AM WERE STILL AT OR A LITTLE BELOW FREEZING IN
MOST AREAS...BUT WILL SOLIDLY GET ABOVE FREEZING IN THE NEXT HOUR OR
TWO. PREVIOUSLY FORECASTED HIGHS RANGING LOWER 40S IN THE NORTH
TO THE UPPER 40S IN THE SOUTH LOOK GOOD AT THIS POINT AND THE ONLY
ADJUSTMENTS FOR THIS UPDATE WERE TO HOURLY TRENDS. /BB/
&&
.PREV DISCUSSION... /ISSUED 401 AM CST SUN FEB 12 2012/
SHORT TERM...TODAY THROUGH MONDAY NIGHT...IT IS A CHILLY MORNING
ACROSS THE ARKLAMISS WITH TEMPERATURES IN THE 20S AREAWIDE. SOME
LOCATIONS HAVE BEEN ABLE TO DIP INTO THE LOWER 20S AND TEENS. A
BRISK NORTH WIND CONTINUES WHICH IS ALLOWING WIND CHILLS TO BE IN
THE TEENS AND LOWER 20S. COMPARED TO THIS TIME 24 HOURS AGO...WE ARE
ABOUT 15 TO 20 DEGREES COLDER. BASED ON RUC ANALYSIS...THE CENTER OF
THE SFC HIGH IS LOCATED JUST SOUTH OF TULSA BUT THE NORTH-SOUTH AXIS
OF THE SFC HIGH IS QUITE EXPANSIVE...RANGING FROM SOUTHERN CANADA TO
THE GULF OF MEXICO.
THE SFC HIGH WILL SHIFT ACROSS THE MID TO LOWER MISSISSIPPI VALLEY
REGION THROUGH THE DAY TODAY AND SHORTWAVE RIDGING WILL MOVE
OVERHEAD. THIS...COUPLED WITH THE PLENTY OF INSOLATION AND LESS
BRISK WINDS AS YESTERDAY...WE SHOULD WARM UP BETTER THAN YESTERDAY.
WHILE LOCATIONS GENERALLY ALONG AND SOUTH OF I-20 WERE ABLE TO REACH
INTO THE LOWER 40S YESTERDAY AFTERNOON...ALL LOCATIONS SHOULD BE
ABLE TO GET INTO THE 40S TODAY. AFTERNOON HIGHS EXPECTED TO RANGE
FROM THE LOWER 40S NORTH TO THE UPPER 40S/AROUND 50 SOUTH.
SOUTHERLY FLOW WILL RESUME BY THIS EVENING INTO TONIGHT...ALLOWING
FOR MOISTURE TO SLOWLY INCREASE BACK INTO THE REGION AND BEGIN SOME
WAA BACK INTO THE REGION. CLOUDS WILL SLOWLY MOVE BACK INTO THE
REGION AND OVERNIGHT LOWS WILL BE WARMING BUT WILL STILL BE ON THE
CHILLY SIDE AS THE COLDEST AIRMASS THIS YEAR DEPARTS. READINGS WILL
RANGE FROM THE UPPER 20S/LOWER 30S WEST TO A CHILLIER LOWER TO MID
20S IN THE EAST...CLOSEST TO THE SFC HIGH.
BY SUNRISE MONDAY...WE SHOULD BE FAIRLY WELL SHROUDED IN CLOUDS. IT
WILL BE SLOW TO WARM DUE TO THE EXTENSIVE CLOUD COVER BUT ALSO
PRECIP WILL BE DEVELOPING JUST TO THE WEST OF THE REGION. MODELS ARE
A LITTLE DIFFERENT IN THE TIMING OF THE ONSET OF PRECIP BUT
OVERALL...WE SHOULD BE SEEING SOME ONSET OF PRECIP BY MID MORNING.
THERE REMAINS SOME POTENTIAL FOR A WINTRY MIX OF PRECIP AT THE
ONSET. MODEL SOUNDINGS SHOW A MOIST LAYER IN THE MID LEVELS WITH
DRIER LOWER LEVELS. AS THE RAIN FALLS THROUGH THIS AND
EVAPORATES...THERE SHOULD BE SOME COOLING WHICH WILL ALLOW THE
PRECIP THAT REACHES THE GROUND TO BE A MIX OF LIGHT SNOW AND OR
LIGHT SLEET. AS THE MORNING WEARS ON INTO THE AFTERNOON...THIS
SHOULD BE MORE OF RAIN/SLEET MIX BEFORE THE ATMOSPHERE MOISTENS
THROUGHOUT THE COLUMN AND WARMS...THUS ENDING WITH ALL RAIN BY THE
AFTERNOON AND EVENING HOURS. THE MOST LIKELY LOCATIONS FOR WINTRY
MIX TO OCCUR WILL BE NORTH OF I-20. GIVEN THE WARMER GROUND TEMPS
AND LIGHT NATURE OF THIS PRECIP...NOT EXPECTING THIS TO ACCUMULATE
OR CAUSE TRAVEL OR ROAD ISSUES.
RAIN WILL CONTINUE MONDAY NIGHT AS THE UPPER TROUGH TRAVERSES NORTH
OF THE REGION. LIFT APPEARS TO BE JUST ENOUGH LATE MONDAY AFTERNOON
INTO THE EVENING FOR THERE TO BE PERHAPS TO BE SOME MODERATE RAIN
BUT OVERALL THE RAIN SHOULD TURN LIGHTER AS THE NIGHT PROGRESSES.
TEMPERATURES MONDAY NIGHT WILL REMAIN WARM ENOUGH TO DISMISS ANY
WINTRY PRECIP ISSUES WITH READINGS IN THE UPPER 30S TO LOWER/MID
40S.
MAIN ADJUSTMENTS TO THE GUI WERE TO CUT HIGH TEMPS MONDAY AS MAV GUI
CONTINUES TO COME IN ON THE HIGHER SIDE. GIVEN TOP DOWN MOISTENING
OF THE ATMOSPHERE...CLOUDS AND RAINFALL...CANT SEE TEMPS GETTING TOO
WARM. ALSO RAISED POPS IN THE DELTA FOR MONDAY AS THIS AREA LOOKS TO
BE MOST FAVORABLE FOR RAINFALL. /28/
LONG TERM...TUESDAY THROUGH SUNDAY...THE FOCUS OF THIS PERIOD WILL
BE ON THE SYSTEM FOR MID WEEK WHICH WILL BRING RAIN/STORMS TO THE
REGION. OUTSIDE THAT...NO MAJOR TEMP SWINGS ARE EXPECTED WITH
GENERALLY CLIMO TYPE (OR SLGT ABV) CONDITIONS EXPECTED.
FOR TUE...LOOK FOR SOME LGT PRECIP LINGERING ACROSS THE E HALF TO
START THE PERIOD...BUT THIS WILL SHIFT EAST EARLY AND I EXPECT THE
PRECIP TO BE OUT OF THE AREA BY 9 AM. WHAT WILL LINGER MOST OF THE
DAY WILL BE LOW CLOUDS. LATEST GUID DATA INDICATES THIS AND THERE
WILL BE AN IMPACT ON TEMPS. THE GFS IS THE OUTLIER AND THE WARMEST
OF THE GUID. FOR THIS FORECAST...THE EURO/NAM TEMPS WERE USED. FOR
I-20 AND NORTH...52-60 DEGREES WILL BE THE RANGE. FURTHER
SOUTH...LESS CLOUD POTENTIAL WILL OFFER A BETTER OPPORTUNITY TO
WARM...HIGHS MAY PUSH 70 NEAR HBG.
FOR WED...THE ATMOSPHERE LOOKS TO TRANSITION QUICKLY TO A WAA REGIME
AND MOISTENING WILL OCCUR WITH RAIN/STORM DEVELOPING BY AFTERNOON
INTO WED NGT. THE EURO HAS BEEN VERY CONSISTENT WITH THIS SYSTEM
BOTH IN TIMING/INTENSITY. AT THIS TIME...NOT EXPECTING ANY SVR
WEATHER...BUT A FEW STRONG STORMS APPEAR POSSIBLE IF THE EURO
VERIFIES. THE GFS BRINGS PRECIP IN SLOWER...BUT MOVES THINGS OUT
QUICKER EARLY THU. THE GFS HAS LESS POTENTIAL FOR STRONG ACTIVITY
AND OFFERS MORE OF A RAIN/FEW TSRA SCENARIO. AS
MENTIONED...FOLLOWING THE EURO ON THIS ONE BUT WILL NOT MENTION ANY
STRONG STORM RISK AT THIS TIME DUE TO UNCERTAINTY BUT WE WILL KEEP
AN EYE ON ANY CHANGES AND ADD A RISK IF CONFIDENCE INCREASES.
TEMPS FOR WED WERE LOWERED MORE IN LINE WITH THE EURO/GFS ENSEMBLE
AS THE OPS GFS WAS THE HIGH MEMBER...MAINLY BECAUSE IT IS THE SLOWER
SOLUTION. ADDITIONALLY...LOW TEMPS WERE RAISED WED NGT AS HIGHER LOW
LEVEL MOISTURE WILL BE IN PLACE. I WAS CONSERVATIVE WITH LOWS THIS
PERIOD AND STAYED IN THE 50S. HOWEVER...IT COULD BE SEVERAL DEGREES
WARMER IF THE LOWER/MID 60 DEWPTS ARRIVE LIKE THE EURO SUGGESTS.
THE REST OF THE EXTENDED LOOKS TO GENERALLY BE QUIET...THERE ARE
DIFFERENCES IN THE GFS/EURO FOR SUNDAY. THE GFS IS WET WHILE THE
EURO DRY. FOR NOW...WILL JUST FOLLOW THE GFS...BUT I EXPECT THE EURO
TO BE MORE CORRECT. GUID TEMPS WERE FOLLOWED FOR THIS PERIOD AS
WELL. THE EXCEPTION WAS SAT MORNING. READINGS WERE WARMED TO MORE OF
A BLEND OF THE EURO/GFS ENSEMBLE. THE OPS GFS WAS ODDLY VERY COLD
AND LOWS WERE WARMED A DECENT AMOUNT. /CME/
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE ACROSS THE REGION TODAY.
DECKS OF HIGH CLOUDS WILL MOVE ACROSS THE AREA WITH N/NE WINDS FROM
5-10KTS. CLOUD COVER WILL INCREASE AND LOWER FOR TONIGHT AS MOISTURE
INCREASES OVER THE AREA BUT CEILINGS ARE EXPECTED TO REMAIN ABOVE
8KFT. WINDS WILL SHIFT TONIGHT OUT OF THE SOUTHEAST AROUND 3-5KTS.
/28/03/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 46 25 51 41 / 0 6 56 86
MERIDIAN 47 22 52 41 / 0 3 36 86
VICKSBURG 45 27 50 42 / 0 11 76 82
HATTIESBURG 51 22 55 48 / 0 5 30 82
NATCHEZ 45 29 55 45 / 0 11 68 81
GREENVILLE 41 26 42 39 / 0 11 86 79
GREENWOOD 42 26 42 38 / 0 6 81 88
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
BB/03/28/CME
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1042 AM EST SUN FEB 12 2012
.SYNOPSIS...
MUCH COLDER AIR WILL CONTINUE TO POUR IN THE REGION THROUGH THE
REMAINDER OF THE WEEKEND. SNOW AND LOCALIZED LAKE EFFECT SNOWS
SOUTHEAST OF THE LAKES WILL CONTINUE THROUGH TONIGHT. ANY
LINGERING SNOW SHOWERS SOUTHEAST OF THE LAKES MONDAY MORNING WILL
END AS HIGH PRESSURE BUILDS INTO THE REGION. ANOTHER WEAK SYSTEM
MAY BRING SOME LIGHT SNOW ON TUESDAY AS TEMPERATURES MODERATE TO
A LITTLE ABOVE AVERAGE AGAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
BAND OF INTENSE LAKE SNOWS DROPPING SOUTH IMPACTING THE NIAGARA
FALLS/BUFFALO AREAS OVER TO ROCHESTER LATE THIS MORNING. THIS BAND
DROPPING SNOWFALL RATES UP TO TWO INCHES PER HOUR. THIS BAND WILL
CONTINUE TO SINK SOUTHWARD BUT LIKELY WEAKEN SOMEWHAT AS IT MOVES
AWAY FROM LAKE INFLUENCES...WHICH IS SUPPORTED BY LATEST HRRR.
LATEST HRRR AND WRF SUGGESTING WEAKER MULTIPLE BANDS WILL CONTINUE
TO IMPACT BOTH LAKES THROUGH THE AFTERNOON. LAKE SNOW HEADLINES WILL
REMAIN INTACT WITH ADDITIONAL AMOUNTS THROUGH THIS AFTERNOON IN THE
2-4/3-5 INCH RANGE IN FAVORED NORTHWEST FLOW AREAS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AT THE START OF THE PERIOD MONDAY MORNING A LAKE EFFECT BAND WILL
STILL BE ONGOING SOUTHEAST OF LAKE ONTARIO. INSTABILITY WILL BE ON
THE WANE...WITH LAKE INDUCED EQUILIBRIUM LEVELS AROUND 6K FEET.
DESPITE THE WEAKENING INSTABILITY...STILL FAVORABLE SNOW GROWTH AND
LONG FETCH SHOULD KEEP A DECENT BAND GOING MONDAY MORNING AS IT
LIFTS ACROSS OSWEGO COUNTY TOWARD THE TUG HILL WITH A FEW INCHES
POSSIBLE. BY MIDDAY LAKE INDUCED INSTABILITY BEGINS TO WEAKEN
FURTHER...AND THAT COMBINED WITH DIMINISHING SYNOPTIC SCALE MOISTURE
AND INCREASING SHEAR WILL BREAK THE BAND APART INTO SCATTERED SNOW
SHOWERS ACROSS THE TUG HILL REGION...THEN END ALTOGETHER BY EARLY
MONDAY EVENING. OFF LAKE ERIE EXPECT LAKE EFFECT TO BE OVER BY 12Z
MONDAY.
OTHERWISE MOST AREAS SHOULD SEE A DECENT AMOUNT OF SUNSHINE ON
MONDAY OUTSIDE OF THE LAKE ONTARIO LAKE EFFECT. MODERATING AIRMASS
SHOULD BRING HIGHS BACK VERY CLOSE TO AVERAGE...LOW 30S ON THE LAKE
PLAINS AND UPPER 20S HIGHER TERRAIN.
LATE MONDAY NIGHT THROUGH TUESDAY OUR ATTENTION TURNS TO THE NEXT
SYNOPTIC SCALE SYSTEM. A MID LEVEL TROUGH EJECTING OUT OF THE PLAINS
WILL GRADUALLY WEAKEN AS IT MOVES EAST THROUGH THE OHIO VALLEY AND
MID ATLANTIC...BUT STILL MAINTAIN ENOUGH FORCING AND DEEP LAYER WARM
ADVECTION/MOISTURE TO SUPPORT A BROAD AREA OF LIGHT SNOW ENTERING
WESTERN NY LATE MONDAY NIGHT OR TUESDAY MORNING...THEN OVERSPREADING
THE REST OF THE AREA ON TUESDAY. AMOUNTS SHOULD BE VERY LIGHT WITH
THIS...PERHAPS AN INCH OR TWO IN SOME SPOTS. TEMPERATURES WARM ABOVE
FREEZING DURING THE AFTERNOON IN MOST LOCATIONS WHICH WILL INHIBIT
ANY FURTHER ACCUMULATION.
THE LIGHT SNOW GRADUALLY TAPERS OF TUESDAY NIGHT AS THE WEAKENING
SYSTEM PULLS OUT TO SEA...BUT WILL LEAVE BEHIND PLENTY OF CLOUD
COVER AS LOW LEVEL MOISTURE BECOMES TRAPPED BENEATH A STEEPENING
INVERSION ALOFT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY BROAD HIGH PRESSURE WILL EXTEND FROM THE OHIO VALLEY NORTH
AND EASTWARD ACROSS THE EASTERN GREAT LAKES REGION. LOW LEVEL
MOISTURE REMAINS PLENTIFUL IN THE LOWER LAYER OF THE
ATMOSPHERE...WHILE ALOFT BOTH THE GFS AND ECMWF HAVE A WEAK SHORT
WAVE CROSSING THE REGION. WILL HAVE LOW CHC POPS WEDNESDAY FOR LIGHT
SNOW...AND AS TEMPERATURE PROFILES WARM...THIS COULD MIX WITH LIGHT
DRIZZLE OR RAIN.
AS MOISTURE WANES SOME BEHIND THE WEAK UPPER LEVEL SHORT WAVE EXPECT
THE SCATTERED LIGHT PRECIPITATION TO COME TO AN END WEDNESDAY
NIGHT...THOUGH MOISTURE WILL STILL REMAIN HIGH ENOUGH TO SUPPORT
PLENTY OF CLOUDS THROUGH THE NIGHT.
THURSDAY AND FRIDAY PRECIPITATION WILL RETURN TO THE REGION AS BOTH
THE 00Z GFS AND ECMWF WITH FAIRLY GOOD SUPPORT FROM THE GEFS HAVE A
PACIFIC SHORTWAVE EJECTING OUT OF THE CENTRAL PLAINS AND TOWARD THE
LOWER LAKES.
INITIALLY RAIN MAY MIX IN THURSDAY ACROSS THE REGION...BUT WITH CAA
BEHIND THE SHORT WAVE A TRANSITION TO ALL SNOW THURSDAY NIGHT AND
FRIDAY IS LIKELY. WHETHER THESE SHORTWAVES PHASE OR NOT WILL LIKELY
IMPACT THE TRACK OF THE STORM...WITH A PHASED SOLUTION TAKING A
STORM PATH TO OUR WEST AND NORTH WITH MILD CONDITIONS THURSDAY. IF
THESE SHORTWAVE DO NOT PHASE...A LESS AMPLIFIED FLOW IS EXPECTED
HOLDING WARMER AIR TO THE SOUTH AND PRECIPITATION FAVORING MORE SNOW
THAN RAIN.
TEMPERATURES ALOFT AT 850 HPA DROP TO -8 TO -10C ON THE GLOBAL
MODELS...AND LAKE ENHANCED SNOW POSSIBLE FRIDAY AND FRIDAY NIGHT AS
THIS SYSTEM PULLS AWAY. BEING DAYS 5 AND 6 WILL STAY WITH CHC POPS
FOR THE WORDING...AND FINE TUNE AS WE DRAW CLOSER TO THE EVENT TIME.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
NORTHWEST FLOW ACROSS THE FORECAST AREA WITHIN AN ARCTIC AIRMASS HAS
TRIGGERED LAKE EFFECT SNOW BANDS SOUTHEAST OF THE LAKE THIS MORNING.
THIS IS ONLY AFFECTING THE KROC AND KJHW SITES WITH MVFR AND
OCCASIONAL IFR VIS/CIGS WITHIN THE AREA OF THE SNOW BAND. ALL OTHER
SITES OUTSIDE OF LAKE EFFECT ARE VFR. REGIONAL IR SATELLITE IS
SHOWING A DISTURBANCE DRIFTING SOUTH FROM EASTERN ONTARIO THAT MAY
BRING SOME VERY LIGHT SNOW TO THE FORECAST AREA THIS MORNING BUT
SHOULD NOT IMPACT AVIATION. WINDS ARE ALSO GUSTY THIS MORNING AS A
TIGHT PRESSURE GRADIENT EXISTS BETWEEN A STRONG HIGH CENTERED OVER
THE CENTRAL U.S. AND A SURFACE LOW OFF THE CANADIAN MARITIMES. HIGH
IS FORECAST TO EXPAND NORTH AND EAST TONIGHT CUTTING OFF MOST LAKE
BANDS WITH WINDS SUBSIDING. ALL SITES SHOULD BE VFR BY LATE TONIGHT
AS SURFACE HIGH TAKES CONTROL OF WEATHER.
OUTLOOK...
MONDAY...MAINLY VFR LOCALLY MVFR/IFR SOUTHEAST OF LAKE ONTARIO.
TUESDAY...VFR/MVFR IN CHC OF SNOW.
WEDNESDAY...MAINLY VFR.
THURSDAY...MVFR WITH A CHANCE OF RAIN/SNOW.
&&
.MARINE...
STRONG HIGH PRESSURE HAS SETTLED ACROSS THE CENTRAL PLAINS AND WILL
BUILD NORTHWARD ACROSS THE LAKES THROUGH THE REMINDER OF THE
WEEKEND. THE PRESSURE GRADIENT ACROSS THE LAKES WILL REMAIN TIGHT
ENOUGH TODAY TO MAINTAIN SMALL CRAFT CONDITIONS ON THE LAKES THROUGH
TONIGHT AND INTO MONDAY. HEAVY FREEZING SPRAY IS STILL POSSIBLE ACROSS
LAKE ERIE THROUGH 10AM THIS MORNING THEN TEMPERATURES RISE HIGH
ENOUGH TO NOT ALLOW CONCERN FOR THESE CONDITIONS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
MONDAY FOR NYZ005-006.
LAKE EFFECT SNOW WARNING UNTIL 6 AM EST MONDAY FOR NYZ004.
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ003.
LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ002.
LAKE EFFECT SNOW ADVISORY UNTIL 6 PM EST THIS EVENING FOR
NYZ012-019-020-085.
LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST MONDAY FOR NYZ014.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR
LOZ042>045.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...TMA
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK/THOMAS
AVIATION...SMITH
MARINE...HITCHCOCK/SMITH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1017 AM EST SUN FEB 12 2012
.SYNOPSIS...
ARCTIC AIR WILL CONTINUE TO SPILL SOUTHEAST INTO THE REGION TODAY.
THE COLD AIR HAS CAUSED LAKE EFFECT SNOW SHOWERS AND FLURRIES,
THAT WILL CONTINUE INTO MONDAY. A WEAK STORM WILL MOVE THROUGH
LATE TUESDAY AND TUESDAY NIGHT WITH A WIDESPREAD LIGHT SNOW.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM...
MAIN BAND OF LE SNOW OVER CAYUGA COUNTY ACROSS WRN CORTLAND AND
ERN TOMPKINS TO BROOME AND TIOGA. HRRR SEEMS TO HAVE A GOOD HANDLE
ON THE BAND AND BEGINS TO LFT IT NEWRD IN RESPONSE TO THE APRCHG
ARCTIC FNT. THIS ALIGNS WITH CRNT RADAR TRENDS AND DVLPG WLY FLOW
SHOW ON SFC OBS. HRRR ALSO SHOWS THE BAND ALONG THE LAKE SHORE
DROPPING SWRD WITH THE FNT AND GIVING MUCH OF THE FCST AREA...ESP
ALONG AND WEST OF I81...ANOTHER GOOD BURST OF SNOW IN THE NEXT FEW
HRS. HAVE ADJUSTED THE CVRG AND INTENSITY OF THE LE FOR THIS
UPDATE...ALONG WITH A FEW OTR MINOR TWEEKS.
4 AM UPDATE...
COLD AIR MOVING INTO THE REGION HAS CONTINUED A GENERAL AREA OF
LAKE EFFECT FLURRIES ACROSS THE CWA. A BAND OF LIGHT TO MODERATE
SNOW IS COMING SOUTHEAST OFF OF LAKE CAYUGA. THIS NNW FLOW WILL
SHIFT TO NW TODAY SO NOT EXPECTING THIS TO LAST BEYOND NOON.
ANOTHER BAND IS CONTINUED TO GEORGIAN BAY INTO ROCHESTER. THIS
SHOULD EXTEND FURTHER INLAND INTO THE FINGER LAKES THIS MORNING
AND CONTINUE THIS AFTERNOON. LAKE EFFECT WILL BECOME HEAVIER
ACROSS CENTRAL NEW YORK AS A SECONDARY COLD FRONT IN SE ONTARIO
MOVES SOUTHEAST TODAY. EXPANDED THE LES ADVISORY TO INCLUDE YATES
AND CHENANGO AS WELL AS TOMPKINS AND TIOGA FOR THE CAYUGA BAND.
IN ADDITION A WIND CHILL ADVISORY CONTINUES FOR NORTHERN ONEIDA
COUNTY THIS MORNING. WIND CHILLS RIGHT AROUND MINUS FIFTEEN F
THERE. THIS AREA WILL WARM SLOWLY AS SEEN HERE. TEMPERATURES AND
DEW POINTS ON THE RISE WITH THE ADDED MOISTURE AND CLOUDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
4 AM UPDATE...
LAKE EFFECT SNOW WILL CONTINUING TONIGHT INTO MONDAY. WAA STARTS
SLOWLY WHILE THE NW FLOW SLOWLY SHIFT TO W. THIS EVENING SNOW
SHOWERS WILL BE ACROSS MOST OF THE CWA WITH THE HEAVIEST ACROSS
THE NORTHERN COUNTIES IN THE ADVISORY. CONNECTION TO GEORGIAN BAY
SHOULD CONTINUE MOST OF THE NIGHT. BY MONDAY MORNING THE LAKE SNOW
WILL BE OUT NE PA. THE FLOW WILL BE 290 INTO ONEIDA COUNTY. A LES
ADVISORY MAY BE NEEDED FOR ONEIDA FOR TONIGHT INTO MONDAY.
MONDAY UPPER LEVEL RIDGING AND WAA WILL QUICKEN. THE LOW LEVEL
SLOW GOES TO THE SW ACROSS THE ENTIRE REGION BY TUESDAY MORNING.
850 WINDS ARE STILL WEST BUT TEMPERATURES NOT ENOUGH TO CREATE
LAKE EFFECT SNOW MONDAY OVERNIGHT.
TUESDAY TEMPERATURES BACK TO NORMAL. INCREASING CLOUDS WITH MAYBE
A FLURRY LATE IN THE DAY.
A WEAK COLD FRONT WILL MOVE THROUGH TUESDAY NIGHT. SOME LIGHT SNOW
SHOWERS ARE EXPECTED WITH IT. MOISTURE AND FORCING ARE LACKING.
THE JET STREAM AND SFC LOW REMAIN WELL SOUTH OF THE REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
4AM UPDATE...
ON THE LARGE-SCALE...MEDIUM RANGE MODELS (EC/GFS/CMC) CONTINUE TO
AGREE FAIRLY WELL THIS CYCLE (00Z SUN)...THAT PACIFIC ORIGIN
DISTURBANCES WILL ZIP ACROSS THE CONUS THIS PD IN A FAST ZONAL FLOW
PATN...AND IMPACT NY/PA ABT EVERY 48 HRS...TRACKING UNDERNEATH A
FLAT ERN CANADIAN TROUGH AND OVER THE TOP OF UPR RIDGING OFF THE
SERN U.S. COAST. ALTHOUGH SOME HIGHER LAT BLOCKING DOES PRESENT
ITSELF ACROSS THE N ATLANTIC FROM TIME TO TIME THIS PD...ITS OVERALL
LACK OF PERSISTENCE SHOULD PRECLUDE ANY MAJOR STORMS FROM TAKING
SHAPE FOR THE NERN U.S. IT APPEARS THAT ANY TRUE ARCTIC AIR MASSES
WILL REMAIN N OF THE U.S./CANADIAN BORDER...ALLOWING TEMPS TO
AVERAGE CLOSE TO SEASONAL NORMS FOR MID TO LATE FEB (HIGHS IN THE
30S AND 40S).
OVERALL...VERY LTL CHANGE WAS MADE TO THE CURRENT SET OF GRIDS. IT
STILL LOOKS LIKE FAST MOVING STORM SYSTEMS WILL BRING SHOTS OF
-RA/-SN INTO WED...AGN TWDS THE END OF THE WEEK (LATE THU AND
FRI)...AND POSSIBLY JUST BEYOND THE PD (SUN INTO MON). A GENERAL
LACK OF VERY COLD AIR WILL LIMIT LAKE RESPONSES FOLLOWING ANY OF
THESE SYSTEMS.
420 PM UPDATE...HPC GRIDS FORMED BASIS OF LONG TERM
FORECAST...WHICH IS INITIALLY DOMINATED BY A SOUTHWEST FLOW THAT
HAS BEEN QUITE FAMILIAR THIS WINTER...AND SO GENERALLY ABOVE
NORMAL TEMPERATURES. HOWEVER...TOWARDS END OF THE PERIOD...THERE
IS UNCERTAINTY AS TO HOW MUCH OF A TROUGH PATTERN COULD SET UP
OVER THE NORTHEAST.
SURFACE HIGH PRESSURE GRADUALLY TAKES CHARGE TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...THOUGH WARM AIR ADVECTION WAVE ALOFT
PASSES THROUGH WITH A FAIR AMOUNT OF MOISTURE. I KEPT ONLY LOW
CHANCE POPS IN TUESDAY NIGHT...BECAUSE OF UNCERTAINTY AS TO IF ANY
PRECIPITATION CAN ACTUALLY REACH THE GROUND. IT MAY INDEED ONLY
TURN OUT TO BE ONLY AN OVERCAST SKY.
NEXT WAVE COMES LATE THURSDAY-FRIDAY...AS EITHER A NEGATIVELY
TILTED COLD FRONT OR AN OCCLUDED FRONT. ECWMF PREFERS MORE OF AN
INSTANT OCCLUSION SCENARIO AS OHIO VALLEY LOW APPROACHES WESTERN NY
THURSDAY EVENING...BUT NEW LOW ALSO DEVELOPS AND STRENGTHENS
OFFSHORE. THAT COULD POTENTIALLY YIELD A FAIR SYNOPTIC SNOW FOR
THE AREA...YET WE COULD ALSO QUICKLY GET INTO DRY SLOT WHICH WOULD
LIMIT AMOUNTS. GFS WAITS UNTIL WELL AFTER FRONT PASSES...BEFORE
ANY COASTAL SURFACE REFLECTION OF NEW LOW BECOMES APPARENT. IN
THIS CASE...PRECIPITATION WOULD BE MORE OF A QUICK SHOT...WITH
MORE TIME FOR WARM AIR TO BE INVOLVED AHEAD OF THE FRONT...SO
PRECIPITATION TYPE IS IN QUESTION. GIVEN ALL OF THESE
UNCERTAINTIES...FIGURED MID CHANCE RANGE POPS OFFERED BY HPC
SUFFICED WELL...AS IT LOOKS UNSETTLED AND WE JUST HAVE TO SORT OUT
THE DETAILS IN COMING DAYS.
GFS DOES BRING A BRIEF PIECE OF COLDER AIR IN BY NEXT
SATURDAY...WITH DEEPER YET ALSO TEMPORARY UPPER TROUGH. I PLACED
SOME CHANCE POPS IN CENTRAL NEW YORK FOR POSSIBLE LAKE EFFECT AT
THAT TIME.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
UPDATED AS OF 7 AM SUN... BANDS OF LES CONTINUE TO IMPACT WRN AND
CNTRL NY ATTM. KITH/KBGM/KSYR WILL BE THE MOST LIKELY SITES TO
EXPERIENCE IFR OVER THE NEAR-TERM...WITH LIGHTER -SHSN/FLRYS PROVIDING
OCNL MVFR RESTRICTIONS AT KRME/KELM/KAVP. IN GENERAL...LES BANDS
SHOULD BREAK UP A BIT THIS AFTN...WITH CONDS IMPROVING TO
VFR...AND OCNL MVFR IN PASSING -SHSN. THIS EVE...ANOTHER LES BAND
IS EXPECTED TO ORGANIZE ACRS UPSTATE NY...AND BRING AN EXTENDED PD
OF IFR TO KSYR...EVENTUALLY REACHING KRME AFTER 06Z.
WINDS WILL BECOME GUSTY AGAIN TODAY OUT OF THE NW (UP TO 25 KT)...SPCLY
AFTER 15Z. GUSTY WINDS SHOULD PERSIST RIGHT THROUGH THE EVE HRS.
.OUTLOOK...
MON...MVFR/IFR POSSIBLE IN KSYR/KRME WITH ONGOING LAKE EFFECT ACTIVITY.
TUE/WED...MVFR/IFR PSBL AT ALL TAF SITES IN LGT SNOW.
THUR...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST MONDAY FOR NYZ015>018-
025-036-044-045-055.
&&
$$
SYNOPSIS...TAC
NEAR TERM...DGM/TAC
SHORT TERM...TAC
LONG TERM...MLJ/MDP
AVIATION...CMG/MLJ
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
534 AM CST SUN FEB 12 2012
.DISCUSSION...UPDATED FOR 12Z AVIATION.
&&
.AVIATION...PASSING UPPER LEVEL DISTURBANCE WILL LEAD TO GRADUALLY
LOWERING CIGS THROUGH TODAY AND INTO TONIGHT. AS OF 12Z ALL AREAS
REMAIN VFR AS LOWER LAYERS OF THE ATMOSPHERE REMAIN DRY. THE
MOISTURE IN THIS LAYER WILL GRADUALLY INCREASE THROUGH THE MORNING
WITH CIGS LOWERING TO MVFR CONDITIONS. LATER IN THE AFTERNOON AND
EVENING PERIODS OF IFR CONDITIONS WILL BE POSSIBLE. WHILE RAIN IS
EXPECTED THROUGH THE DAY...A SLIGHT CHANCE OF THUNDERSTORMS WILL
DEVELOP THIS EVENING AND OVERNIGHT. EXPECT LITTLE TO NO
IMPROVEMENT IN CONDITIONS BY THE END OF THIS TAF PERIOD...BUT
CONDITIONS SHOULD IMPROVE QUICKLY MONDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 437 AM CST SUN FEB 12 2012/
SHORT TERM (TODAY THROUGH MONDAY)...SEEING PATCHY LIGHT RAIN OR
DRIZZLE DEVELOP ACROSS SOUTHWEST CWA THIS MORNING ASSOCIATED WITH
THE FIRST PIECE OF ENERGY THAT WILL AFFECT THE AREA OVER THE NEXT
COUPLE OF DAYS. DPT DEPRESSIONS ARE STILL QUITE HIGH THIS
MORNING...10 TO 15 DEGREES FOR MOST LOCATIONS...SO WILL TAKE SOME
TIME TO REALLY GET ANY SUBSTANTIAL RAIN TODAY. RUC SOUNDINGS SHOW
LOW LEVELS BECOMING SATURATED BY MID TO LATE MORNING ACROSS THE
AREA. 300K SURFACE COND PRES DEFICITS LAG A BIT BEHIND THIS
TIMING...BUT 295K SURFACE IS A BIT QUICKER. WITH 25 TO 35KT
ISENTROPIC UPGLIDE THINK BY MID MORNING SOUTHWEST PORTION OF THE
CWA WILL BE SEEING LIGHT RAIN. WHILE TEMPERATURE PROFILE WILL BE
ABOVE ZERO IN THE LOWEST 200 MB...EVAPORATIVE COOLING WILL LIKELY
BRING THE PROFILE A LITTLE CLOSER TO ZERO FOR A TIME THIS MORNING.
HOWEVER THINK PRECIP SHOULD REMAIN IN THE LIQUID PHASE AT THE
SURFACE FOR ALL AREAS. RAIN CHANCES INCREASE THROUGHOUT THE DAY
AS UPGLIDE CONTINUES. PWAT VALUES REMAIN RELATIVELY LOW THROUGH
THE DAY...JUST ABOVE 1 INCH...WHICH SHOULD KEEP THE RAIN MAINLY
LIGHT. AN UPPER LEVEL JET STREAK MOVING INTO GOOD POSITION OVER
THE FORECAST AREA TONIGHT...AND SOME DECENT LOW TO MID LEVEL OMEGA
WILL BRING A SLIGHT CHANCE FOR THUNDER TONIGHT INTO MONDAY.
ISENTROPIC UPGLIDE CUTS OFF QUICKLY LATE MORNING AND EARLY
AFTERNOON ON MONDAY WITH MOISTURE ALSO QUICKLY DECREASING AS LAYER
WINDS SHIFT TO THE WEST. EXPECT MOST AREAS TO BE DONE WITH RAIN BY
AROUND NOON ON MONDAY. SOME RAIN COULD BE LINGERING FAR EAST.
SKIES SHOULD BEGIN TO CLEAR PRETTY QUICKLY IN THE AFTERNOON.
AS FOR TEMPERATURES...WILL SEE LITTLE INCREASE IN TEMPS THIS
AFTERNOON. WITH RUC MODEL ACTUALLY SHOWING HIGHS IN THE LOW TO MID
40S...BUT THINK THIS IS A BIT TOO LOW. MOST MODELS INDICATING HIGHS
IN THE LOWER TO MID 50S. FORECAST WILL REFLECT NEAR OR SLIGHTLY
UNDER A CONSENSUS OF GUIDANCE. WINDS SHIFT SOUTH AND SOUTHWEST FOR
MONDAY AND EXPECT TEMPS 15 TO 20 DEGREES HIGHER AREA WIDE.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...THE GFS/CANADIAN/ECMWF
PROG AN UPPER DISTURBANCE TO MOVE ACROSS THE SRN PLAINS/NRN TX
WEDNESDAY. RTN FLOW/INCREASING MSTR EXPECTED TUESDAY IN ADVANCE OF
THIS SYSTEM. THE GFS/ECWMF PROG A COLD FRONT...CORRESPONDING TO THE
UPPER DISTURBANCE...TO MOVE ACRS THE CWA WEDNESDAY AFTN/EVENING. THE
COMBINATION OF SFC AND UPPER FORCING WILL CONTRIBUTE TO CONVECTION
WEDNESDAY (GREATEST CHANCE OVER THE ERN CWA BASED ON MSTR
CONSIDERATIONS) WITH ACTIVITY ENDING AFTER FROPA. ANTICIPATE SCA
CONDITIONS OVER AT LEAST THE OFFSHORE COASTAL WATERS THURSDAY IN
RESPONSE TO THE FRONT. THE MODELS DIFFER WITH RESPECT TO THE UPPER
PATTERN THURSDAY-SATURDAY. REGARDLESS...ALL SOLNS APPEAR TO PROG AN
UPPER PATTERN CONSISTENT WITH ISENTROPIC LIFT. YET...THE GFS PROGS
ISENTROPIC LIFT SAT AND THE ECMWF SUNDAY. WILL ACCOUNT FOR
UNCERTAINTY BY FCSTG LOW POP PCPN FOR SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 53 53 73 54 74 / 60 90 50 0 10
VICTORIA 49 49 68 49 73 / 30 80 70 10 0
LAREDO 48 47 69 54 79 / 80 50 20 0 0
ALICE 51 51 71 52 76 / 60 90 40 0 0
ROCKPORT 54 54 70 57 68 / 40 90 60 10 10
COTULLA 46 44 67 49 77 / 50 60 20 0 0
KINGSVILLE 54 54 73 53 76 / 70 90 40 0 0
NAVY CORPUS 55 55 72 59 69 / 60 90 50 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT
20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS
FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
PZ/83...SHORT TERM
WC/87...LONG TERM
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
437 AM CST SUN FEB 12 2012
.SHORT TERM (TODAY THROUGH MONDAY)...SEEING PATCHY LIGHT RAIN OR
DRIZZLE DEVELOP ACROSS SOUTHWEST CWA THIS MORNING ASSOCIATED WITH
THE FIRST PIECE OF ENERGY THAT WILL AFFECT THE AREA OVER THE NEXT
COUPLE OF DAYS. DPT DEPRESSIONS ARE STILL QUITE HIGH THIS
MORNING...10 TO 15 DEGREES FOR MOST LOCATIONS...SO WILL TAKE SOME
TIME TO REALLY GET ANY SUBSTANTIAL RAIN TODAY. RUC SOUNDINGS SHOW
LOW LEVELS BECOMING SATURATED BY MID TO LATE MORNING ACROSS THE
AREA. 300K SURFACE COND PRES DEFICITS LAG A BIT BEHIND THIS
TIMING...BUT 295K SURFACE IS A BIT QUICKER. WITH 25 TO 35KT
ISENTROPIC UPGLIDE THINK BY MID MORNING SOUTHWEST PORTION OF THE
CWA WILL BE SEEING LIGHT RAIN. WHILE TEMPERATURE PROFILE WILL BE
ABOVE ZERO IN THE LOWEST 200 MB...EVAPORATIVE COOLING WILL LIKELY
BRING THE PROFILE A LITTLE CLOSER TO ZERO FOR A TIME THIS MORNING.
HOWEVER THINK PRECIP SHOULD REMAIN IN THE LIQUID PHASE AT THE
SURFACE FOR ALL AREAS. RAIN CHANCES INCREASE THROUGHOUT THE DAY
AS UPGLIDE CONTINUES. PWAT VALUES REMAIN RELATIVELY LOW THROUGH
THE DAY...JUST ABOVE 1 INCH...WHICH SHOULD KEEP THE RAIN MAINLY
LIGHT. AN UPPER LEVEL JET STREAK MOVING INTO GOOD POSITION OVER
THE FORECAST AREA TONIGHT...AND SOME DECENT LOW TO MID LEVEL OMEGA
WILL BRING A SLIGHT CHANCE FOR THUNDER TONIGHT INTO MONDAY.
ISENTROPIC UPGLIDE CUTS OFF QUICKLY LATE MORNING AND EARLY
AFTERNOON ON MONDAY WITH MOISTURE ALSO QUICKLY DECREASING AS LAYER
WINDS SHIFT TO THE WEST. EXPECT MOST AREAS TO BE DONE WITH RAIN BY
AROUND NOON ON MONDAY. SOME RAIN COULD BE LINGERING FAR EAST.
SKIES SHOULD BEGIN TO CLEAR PRETTY QUICKLY IN THE AFTERNOON.
AS FOR TEMPERATURES...WILL SEE LITTLE INCREASE IN TEMPS THIS
AFTERNOON. WITH RUC MODEL ACTUALLY SHOWING HIGHS IN THE LOW TO MID
40S...BUT THINK THIS IS A BIT TOO LOW. MOST MODELS INDICATING HIGHS
IN THE LOWER TO MID 50S. FORECAST WILL REFLECT NEAR OR SLIGHTLY
UNDER A CONSENSUS OF GUIDANCE. WINDS SHIFT SOUTH AND SOUTHWEST FOR
MONDAY AND EXPECT TEMPS 15 TO 20 DEGREES HIGHER AREA WIDE.
&&
.LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...THE GFS/CANADIAN/ECMWF
PROG AN UPPER DISTURBANCE TO MOVE ACROSS THE SRN PLAINS/NRN TX
WEDNESDAY. RTN FLOW/INCREASING MSTR EXPECTED TUESDAY IN ADVANCE OF
THIS SYSTEM. THE GFS/ECWMF PROG A COLD FRONT...CORRESPONDING TO THE
UPPER DISTURBANCE...TO MOVE ACRS THE CWA WEDNESDAY AFTN/EVENING. THE
COMBINATION OF SFC AND UPPER FORCING WILL CONTRIBUTE TO CONVECTION
WEDNESDAY (GREATEST CHANCE OVER THE ERN CWA BASED ON MSTR
CONSIDERATIONS) WITH ACTIVITY ENDING AFTER FROPA. ANTICIPATE SCA
CONDITIONS OVER AT LEAST THE OFFSHORE COASTAL WATERS THURSDAY IN
RESPONSE TO THE FRONT. THE MODELS DIFFER WITH RESPECT TO THE UPPER
PATTERN THURSDAY-SATURDAY. REGARDLESS...ALL SOLNS APPEAR TO PROG AN
UPPER PATTERN CONSISTENT WITH ISENTROPIC LIFT. YET...THE GFS PROGS
ISENTROPIC LIFT SAT AND THE ECMWF SUNDAY. WILL ACCOUNT FOR
UNCERTAINTY BY FCSTG LOW POP PCPN FOR SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 53 53 73 54 74 / 60 90 50 0 10
VICTORIA 49 49 68 49 73 / 30 80 70 10 0
LAREDO 48 47 69 54 79 / 80 50 20 0 0
ALICE 51 51 71 52 76 / 60 90 40 0 0
ROCKPORT 54 54 70 57 68 / 40 90 60 10 10
COTULLA 46 44 67 49 77 / 50 60 20 0 0
KINGSVILLE 54 54 73 53 76 / 70 90 40 0 0
NAVY CORPUS 55 55 72 59 69 / 60 90 50 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT
20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS
FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
PZ/83...SHORT TERM
WC/87...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
540 AM CST SUN FEB 12 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
206 AM CST SUN FEB 12 2012
MAIN FORECAST CONCERN IS ON LIGHT SNOW FOR MONDAY INTO MONDAY
NIGHT
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER SOUTHWEST INTO SOUTH CENTRAL CANADA...AS WELL AS
OVER TEXAS INTO COLORADO...A SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST...A DEEPER SHORTWAVE TROUGH OVER THE DESERT SOUTHWEST...
AND A LONG-WAVE TROUGH ALONG THE EASTERN SEABOARD. WITH 500MB HEIGHTS
RISING OVER THE FORECAST AREA BEHIND THE LONG-WAVE TROUGH...WARMER
AIR ALOFT IS BEGINNING TO FLOW IN FROM CENTRAL CANADA. INTERESTING
THAT BETWEEN 00Z ON THE 10TH AND 00Z ON THE 12TH...850MB TEMPS HAVE
WARMED ABOUT 16C ACROSS MUCH OF CENTRAL CANADA PER 00Z RAOBS. IN
FACT...850MB TEMPS AT 00Z WERE -3C AT CHURCHILL MANITOBA...WARMER
THAN THE AVERAGE -13C OVER THE FORECAST AREA. AIRMASS REMAINS DRY
ACROSS THE ENTIRE UPPER MIDWEST...CENTRAL PLAINS AND UPPER
MISSISSIPPI RIVER VALLEY REGIONS...NOTED BY PRECIPITABLE WATER
VALUES BETWEEN 0.05-0.1 INCHES ON 00Z SOUNDINGS. THIS DRY AIR IS
ASSOCIATED WITH AN AREA OF HIGH PRESSURE AT THE SURFACE THAT
ENCOMPASSES ALL OF THE U.S. PLAINS. A SUSTAINED 5 TO 15 MPH
NORTHWEST WIND OVER THE FORECAST AREA...ON THE EAST SIDE OF HIGH...
HAS ONLY ALLOWED TEMPERATURES TO FALL INTO THE 8 TO 15F RANGE.
TODAY AND TONIGHT...THE UPPER RIDGING SEEN FROM TEXAS INTO COLORADO
IS PROGGED TO LIFT NORTHEAST TOWARDS THE AREA DURING THIS
PERIOD...IN RESPONSE TO THE TWO SHORTWAVE TROUGHS OUT WEST MOVING
OUT INTO THE WESTERN PLAINS. MOISTURE TRANSPORT OUT OF THE GULF OF
MEXICO AND DPVA AHEAD OF THESE TROUGHS SHOULD CAUSE PRECIPITATION TO
BREAK OUT ACROSS MUCH OF THE PLAINS TONIGHT...PERHAPS REACHING INTO
WESTERN IOWA LATE IN THE NIGHT. FOR OUR AREA...WE WILL REMAIN
INFLUENCED BY THE DRY AIR ASSOCIATED WITH THE SURFACE HIGH...AND ITS
RIDGE AXIS LOOKS TO CROSS TONIGHT. FULL SUN ANTICIPATED TODAY AND
WITH 850MB TEMPS PROGGED AROUND -6C AT 18Z...TEMPERATURES SHOULD
CLIMB INTO THE MID 20S TO NEAR 30. WILL STILL BE DEALING WITH A
NORTHWEST TO WESTERLY BREEZE...BUT IT DOES NOT LOOK AS BREEZY AS
YESTERDAY WITH A WEAKER PRESSURE GRADIENT PROGGED. THE WINDS MAY
HAVE A SHOT OF DECOUPLING TONIGHT...ESPECIALLY OVER WESTERN
WISCONSIN...SETTING UP BETTER RADIATIONAL COOLING. ON THE FLIP
SIDE...A WARMER DAY TODAY WILL PROBABLY END UP RESULTING IN LOWS
SIMILAR TO THOSE EXPERIENCED THIS MORNING. INCREASING MID/HIGH
CLOUDS LATER IN THE NIGHT WEST OF THE MISSISSIPPI RIVER SHOULD KEEP
TEMPERATURES A LITTLE WARMER THERE.
MONDAY AND MONDAY NIGHT...MODELS ARE IN GOOD AGREEMENT TAKING THE
TROUGHING OVER THE WESTERN PLAINS AT 12Z MONDAY MOSTLY INTO THE OHIO
VALLEY REGION MONDAY NIGHT. THERE IS A NORTHERN EXTENSION THAT
CROSSES THE FORECAST AREA LATE MONDAY INTO THE EARLY OVERNIGHT HOURS
MONDAY NIGHT. WITH THE BULK OF THE TROUGH HEADING MORE TO THE
SOUTH...THERE IS CONCERN ON HOW MUCH MOISTURE CAN MAKE IT NORTH INTO
THE FORECAST AREA. CERTAINLY MODELS SUGGEST IT HAPPENS ENOUGH TO
PRODUCE SOME LIGHT QPF ACROSS MUCH OF THE FORECAST AREA...THOUGH THE
BEST MOISTURE TRANSPORT AND ISENTROPIC LIFT STAYS TO THE SOUTH AND
EAST. SO BASICALLY THE HEIGHT FALLS AND DPVA FROM THE NORTHERN
EXTENSION OF THE TROUGH WILL BE THE MAIN FORCING FUNCTION FOR THE
PRECIPITATION. LOOKS LIKE PRECIPITATION SHOULD SLOWLY WORK SOUTHWEST
TO NORTHEAST ACROSS THE AREA ON MONDAY...WITH THE LINGERING DRY AIR
THE MAIN REASON FOR THE SLOW ADVANCEMENT. PRECIPITATION THEN
DIMINISHES WEST TO EAST AFTER MIDNIGHT MONDAY NIGHT AS THE TROUGH
PUSHES EAST. GOOD MODEL AGREEMENT REMAINS ON THIS LIGHT
PRECIPITATION EVENT...SO HAVING THE HIGH PRECIPITATION CHANCES AS
INDICATED BY THE PREVIOUS FORECAST SEEM REASONABLE. ONLY SLIGHT
UPWARD MODIFICATIONS WERE MADE. WITH RESPECT TO AMOUNTS...THINK THE
12.00Z NAM IS A LITTLE TOO HIGH ON QPF GIVEN WEAK FORCING OVERALL.
SHOULD MAINLY BE A 0.5 TO 1.5 INCH SNOW EVENT...WITH PERHAPS A
FEW TOTALS SLIGHTLY HIGHER THAN THAT. WITH A FLOW OF WARMER AIR
COMING IN WITH THE TROUGH...SLIGHTLY HIGHER HIGHS ARE ANTICIPATED
FOR MONDAY COMPARED TO TODAY. IN FACT...AREAS ACROSS WISCONSIN
COULD EVEN SEE SOME SUN IN THE MORNING. CLOUDY SKIES ARE EXPECTED
ACROSS THE AREA MONDAY NIGHT...AND WITH LITTLE OR NO COLD
ADVECTION...TEMPERATURES SHOULD ONLY DROP MAYBE 5 DEGREES FOR
LOWS.
TUESDAY AND TUESDAY NIGHT...IN THE WAKE OF THE MONDAY/MONDAY
TROUGH...MODELS SHOW ONE MORE SHORTWAVE MOVING WEST TO EAST ACROSS
THE FORECAST AREA LATE TUESDAY. APPEARS THIS SHORTWAVE WILL NOT HAVE
MUCH MOISTURE OR EVEN PRODUCE MUCH FORCING...THEREFORE HAVE DRY
CONDITIONS FOR TUESDAY. ON TUESDAY NIGHT...TROUGHING IS FORECAST TO
DROP DOWN INTO MANITOBA WHILE TROUGHING IS SHOWN AGAIN OVER THE
SOUTHWESTERN U.S.. HOWEVER...NEITHER FEATURE IS CLOSE ENOUGH TO
BRING ANY PRECIPITATION TO THE AREA. IN FACT...THERE SHOULD BE SOME
SLIGHT 500MB HEIGHT RISES TAKING PLACE. THEREFORE...DRY CONDITIONS
CONTINUE. 850MB TEMPS PROGGED AROUND -6C ON TUESDAY COMBINED WITH
SOME SLOW CLEARING AND A WARMER START WILL ALLOW FOR HIGHS A FEW
DEGREES WARMER THAN MONDAY. A LITTLE BETTER NIGHT INDICATED FOR
RADIATIONAL COOLING TUESDAY NIGHT WITH LIGHT WINDS...THOUGH THE
AIRMASS OVERALL IS RELATIVELY SPEAKING WARM WITH 850MB TEMPS HOLDING
NEARLY STEADY. IN ADDITION...THERE ARE HINTS OF SOME STRATUS TO MOVE
IN LATER IN THE NIGHT. FOR NOW...FOLLOWED A BLEND OF GUIDANCE FOR
LOWS.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
206 AM CST SUN FEB 12 2012
12.00Z MODELS (ECMWF/CANADIAN/UKMET/GFS/GFS ENSEMBLES) DEPICT A
MESSY UPPER LEVEL FLOW PATTERN THROUGHOUT THE LONG TERM...RESULTING
IN QUITE A FEW DIFFERENCES BETWEEN ALL THE MODELS. IT APPEARS THIS
IS A RESULT OF A FAST...ZONAL FLOW ACROSS THE PACIFIC RUNNING INTO
SPLIT FLOW OVER THE U.S. AND SOUTHERN CANADA. DESPITE THE
DIFFERENCES OF HANDLING SHORTWAVES...IN GENERAL THE LONG TERM PERIOD
LOOKS PRETTY QUIET WITH ALL OF THE COLD...ARCTIC AIR BEING LOCKED UP
OVER VERY FAR NORTHERN CANADA. THERE ARE A FEW FEATURES THAT MODELS
AGREE UPON AND WILL DISCUSS THEM HERE. THE FIRST IS THE TROUGHING
THAT DEVELOPS OVER THE SOUTHWESTERN U.S. TUESDAY NIGHT. 12.00Z
ECMWF/GFS/UKMET ARE ALL IN AGREEMENT ON SHEARING THIS TROUGH OUT AND
TRACKING IT THROUGH THE OHIO VALLEY ON THURSDAY. THIS TRACK AND
GIVEN THE FACT THAT IS SHEARING WOULD KEEP THE BULK OF THE
PRECIPITATION SOUTH OF THE FORECAST AREA...OR PERHAPS CLIP NORTHEAST
IOWA AND FAR SOUTHWEST WISCONSIN. THE 12.00Z CANADIAN IS THE ONLY
MODEL NOW STILL SUGGESTING A FARTHER NORTH...MORE PHASED LOOK...
WHICH RESULTS IN A DEEPER SYSTEM SPREADING PRECIPITATION OVER MUCH
OF THE AREA WEDNESDAY NIGHT INTO THURSDAY. HAVE LOWERED
PRECIPITATION CHANCES SOME DURING THIS PERIOD GIVEN THE TREND TO THE
UN-PHASED LOOK...AND STILL WOULD NOT BE SURPRISED IF IT ENDS UP DRY
LIKE THE 12.00Z GFS SHOWS. UPPER LEVEL TROUGHING DOES DEVELOP OVER
THE UPPER MISSISSIPPI RIVER VALLEY REGION EASTWARD INTO NEW ENGLAND
FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT. 850MB TEMPS ARE ONLY AROUND
-4C IN THE TROUGH SO AGAIN...NOTHING THAT COLD. FLOW THEN TURNS MORE
ZONAL FOR SATURDAY OVER THE AREA WITH NO PRECIPITATION SEEN. SO
OUTSIDE OF THE WEDNESDAY NIGHT/THURSDAY TIME PERIOD...A DRY LONG
TERM FORECAST IS EXPECTED. NO BIG WARM-UPS PLANNED EITHER.
HOWEVER...GIVEN 850MB TEMPS STAYING MOSTLY BETWEEN -4C AND 1C...
SURFACE TEMPERATURES SHOULD AT LEAST END UP 5-10 DEGREES NORMAL FOR
BOTH HIGHS AND LOWS. LOOKING FARTHER OUT INTO EARLY NEXT
WEEK...STILL NO SUGGESTIONS OF ANY MAJOR COOL DOWNS AS THE FAST
PACIFIC FLOW CONTINUES...ALLOWING PACIFIC AIR TO CONTINUE TO FLOW
ACROSS THE U.S.
&&
.AVIATION...TODAY AND TONIGHT
545 AM CST SUN FEB 12 2012
HIGH PRESSURE WILL CONTINUE TO PROVIDE CLEAR SKIES THROUGH THIS
EVENING...AND THEN A SCATTERED TO BROKEN CIRROSTRATUS DECK WILL
MOVE INTO THE AREA AFTER 13.09Z. THE WIND DIRECTION WILL BE
PRIMARILY WEST TODAY AND THEN GRADUALLY SHIFT TO SOUTH TONIGHT.
WIND SPEEDS THROUGH THE PERIOD WILL BE 10 KNOTS OR LESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
206 AM CST SUN FEB 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
943 AM PST SUN FEB 12 2012
.DISCUSSION...AS OF 9:00 AM PST SUNDAY...LOW CLOUDS WITH POCKETS
OF DENSE FOG CONTINUE ACROSS NORTH BAY VALLEYS THIS MORNING WITH A
FEW REPORTS OF VIS DOWN TO LESS THAN 1/8 OF A MILE. CURRENT
ADVISORY GOES UNTIL 9 AM WHICH IS THE TYPICAL TIME FOR CONDITIONS
TO RAPIDLY IMPROVE...HOWEVER OBS JUST IN BEFORE THE TOP OF THE HOUR
STILL SHOW LESS THAN 1/4 MILE IN SPOTS SO WILL EXTEND IT UNTIL 11 AM.
OVERALL PLENTY OF CLOUDS ARE EXPECTED TODAY AS A COLD FRONT MAKES
ITS WAY INTO OUR CWA. TIMING OFF THE NEW NAM AND RUC HAS CHANGED
ONLY A LITTLE SO WILL LET THE CURRENT TIMING RIDE. THINK THAT RAIN
WILL ENTER NAPA/SONOMA BY LATE IN THE AFTERNOON AND ACROSS OUR
ENTIRE AREA OVERNIGHT. RAINFALL TOTALS DO NOT LOOK
IMPRESSIVE ALTHOUGH THE WIDESPREAD NATURE OF THIS SHOULD GIVE
ALMOST ALL SPOTS AT LEAST A FEW HUNDREDTHS. EVEN AREAS THAT ARE
PRONE TO HIGH RAINFALL AMOUNTS (BEN LOMAND AND VENADO FOR EXAMPLE)
SHOULD GET LESS THAN 1/3" BY TONIGHT. BEHIND THE FRONT WINDS WILL
PICK UP GENERALLY IN A NORTH TO NORTHWEST PATTERN. 925 MB SPEEDS
SHOW THE BEST VALUES OVER THE WATER AND ALONG THE COAST AND LOOKS
LIKE WE COULD SEE AREAS OF WINDS CLOSE TO 50 MPH. BIGGEST CONCERN
WOULD BE FROM THE SAN MATEO COASTLINE INLAND TO HIGHER ELEVATION
SPOTS. SECONDARY WOULD BE AROUND PT REYES. WILL TAKE A CLOSER LOOK
AT THIS AND POSSIBLE ISSUE A WIND ADVISORY FOR THOSE TWO SPOTS.
.PREVIOUS DISCUSSION...SATL IMAGERY AS WELL AS SFC OBS INDC PATCHY
FOG...LOCALLY DENSE IN THE NORTH BAY VALLEYS. WILL CONSIDER
ISSUING A DENSE FOG ADVISORY IF THE DENSE FOG PERSISTS...BUT NAPA
HAS A VIS OF 1SM. LOW CLOUDS ARE COMMON ACROSS MOST OF THE
DISTRICT WITH A WEAK ONSHORE FLOW. AS OF 11Z (3 AM PST) THE
GRADIENT BETWEEN SFO-SAC IS ONSHORE AT 0.8 MB AND THE GRADIENT
BETWEEN SFO-WMC IS ONSHORE AT 4.3 MB.
SATL IMAGERY IS INDC A SHORTWAVE PASSING 145W. THIS SHORTWAVE WILL
MOVE TO THE COAST TONIGHT WITH THE ASSOCIATED COLD FRONT MOVING
ACROSS THE DISTRICT OVERNIGHT. THIS SHORTWAVE WILL CUTOFF AS IT
MOVES ACROSS NORTHERN AND CENTRAL CALIFORNIA ON MONDAY. RAIN
TONIGHT WILL TAPER OFF TO SHOWERS ON MONDAY IN THE MOIST NW FLOW
AFTER THE FRONT PASSES. THERE COULD BE EVEN ENOUGH COLD AIR TO
BRING A LITTLE SNOW TO THE HIGHER PEAKS IN MONTEREY AND SAN BENITO
COUNTIES. SHOWERS COULD LINGER IN THE SOUTHERN PORTIONS OF THE
DISTRICT MONDAY NIGHT. ADDITIONALLY...BRISK NORTHWEST WINDS WILL
DEVELOP MONDAY INTO MONDAY NIGHT WITH THE STRONGEST WINDS IN THE
HILLS AND ALONG THE COAST. AS OF NOW...THE WINDS DO NOT LOOK LIKE
THEY WILL REACH ADVISORY CRITERIA.
MODELS ARE NOT IN AGREEMENT FOR THE NEXT UPSTREAM SYSTEM. THE GFS
CUTS OFF AN UPPER LOW AND DROPS IT ALONG THE COAST LATE TUESDAY
AND TUESDAY NIGHT...WHICH WOULD BRING SHOWERS TO THE DISTRICT.
THE ECMWF KEEPS THE SYSTEM IN WA TUESDAY...THEN BRINGS IT
SOUTHEAST THROUGH THE INTER MOUNTAIN WEST...WHICH WOULD KEEP THE
DISTRICT DRY. THE 00Z GFS ENSEMBLES ARE BASICALLY SPLIT BETWEEN
THE TWO SOLUTIONS. THEREFORE...HAVE KEPT A SLIGHT CHANCE OF RAIN
FOR LATE TUESDAY IN THE NORTH BAY AND ACROSS THE DISTRICT TUESDAY
NIGHT.
MODELS DO AGREE IN BUILDING A RIDGE INTO THE STATE WEDNESDAY
THROUGH FRIDAY. THIS WILL RESULT IN DRY AND MILD WEATHER. THE
ECMWF BRINGS ANOTHER SYSTEM INTO THE PACIFIC NW AND NORTHERN CA
FRIDAY NIGHT AND SATURDAY. HAVE KEPT THE CHC/SLT CHC OF RAIN FOR
THE NORTH BAY FRIDAY NIGHT AND SAT. THE 06Z GFS IS TRENDING
TOWARDS THE ECMWF SOLUTION...IF THIS TREND CONTINUES THEN POPS
MIGHT NEED TO BE INCREASED FOR THIS PERIOD.
&&
.AVIATION......AS OF 9:43 AM PST SUNDAY...SCATTERED CLOUDS AROUND
THE BAY AREA WILL BEGIN TO CLEAR OUT BY LATE MORNING. FOG IN THE
NORTH BAY WILL CLEAR UP AS WELL. A COLD FRONT MOVING THROUGH
TONIGHT WILL INCREASSE WINDS THIS EVENING AND SPREAD RAIN FROM
NORTH TO SOUTH AFTER 03Z.
VICINITY OF KSFO...VFR TODAY. CIGS WILL REDEVELOP AFTER 06Z
TONIGHT WITH INCREASING PRECIP CHANCES. WINDS WILL RAMP UP
OVERNIGHT AS WELL WITH GUSTS OVER 20 KT BY MONDAY MORNING.
KSFO BRIDGE APPROACH....SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...MVFR CIGS THROUGH 20-22Z WITH SCT
CIGS THERE AFTER. CIGS REDEVELOP OVERNIGHT WITH RAIN POSSIBLE BY
MONDAY MORNING.
&&
.MARINE...AS OF 3:40 AM PST SUNDAY...NORTHWEST WINDS WILL INCREASE
OVER THE COASTAL WATERS TONIGHT AS A STORM SYSTEM APPROACHES.
LATEST MODELS DEVELOP GALE FORCE WINDS OVER THE OUTER WATERS
TONIGHT AND MONDAY. OCCASIONAL GALE FORCE GUSTS WILL ALSO BE
POSSIBLE OVER THE INNER WATERS. THE STRONG AND GUSTY WINDS WILL BE
CAPABLE OF PRODUCING STEEP FRESH SWELL. IN ADDITION...THE SEA STATE
WILL INCREASE WITH WAVES GREATER THAN 10 FT DEVELOPING OVER THE
BAR. MARINERS VENTURING ON THE WATERS ON MONDAY SHOULD CHECK THE
LATEST OBSERVATIONS AND USE CAUTION.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...DENSE FOG ADVISORY...NORTH BAY VALLEYS UNTIL 11 AM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 10 AM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 10 AM
SCA...ROUGH BAR ADVISORY FOR SF BAR
&&
$$
PUBLIC FORECAST: BELL/STROBIN
AVIATION/MARINE: SIMS
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
903 AM PST SUN FEB 12 2012
.DISCUSSION...AS OF 9:00 AM PST SUNDAY...LOW CLOUDS WITH POCKETS
OF DENSE FOG CONTINUE ACROSS NORTH BAY VALLEYS THIS MORNING WITH A
FEW REPORTS OF VIS DOWN TO LESS THAN 1/8 OF A MILE. CURRENT
ADVISORY GOES UNTIL 9 AM WHICH IS THE TYPICAL TIME FOR CONDITIONS
TO RAPIDLY IMPROVE...HOWEVER OBS JUST IN BEFORE THE TOP OF THE HOUR
STILL SHOW LESS THAN 1/4 MILE IN SPOTS SO WILL EXTEND IT UNTIL 11 AM.
OVERALL PLENTY OF CLOUDS ARE EXPECTED TODAY AS A COLD FRONT MAKES
ITS WAY INTO OUR CWA. TIMING OFF THE NEW NAM AND RUC HAS CHANGED
ONLY A LITTLE SO WILL LET THE CURRENT TIMING RIDE. THINK THAT RAIN
WILL ENTER NAPA/SONOMA BY LATE IN THE AFTERNOON AND ACROSS OUR
ENTIRE AREA OVERNIGHT. RAINFALL TOTALS DO NOT LOOK
IMPRESSIVE ALTHOUGH THE WIDESPREAD NATURE OF THIS SHOULD GIVE
ALMOST ALL SPOTS AT LEAST A FEW HUNDREDTHS. EVEN AREAS THAT ARE
PRONE TO HIGH RAINFALL AMOUNTS (BEN LOMAND AND VENADO FOR EXAMPLE)
SHOULD GET LESS THAN 1/3" BY TONIGHT. BEHIND THE FRONT WINDS WILL
PICK UP GENERALLY IN A NORTH TO NORTHWEST PATTERN. 925 MB SPEEDS
SHOW THE BEST VALUES OVER THE WATER AND ALONG THE COAST AND LOOKS
LIKE WE COULD SEE AREAS OF WINDS CLOSE TO 50 MPH. BIGGEST CONCERN
WOULD BE FROM THE SAN MATEO COASTLINE INLAND TO HIGHER ELEVATION
SPOTS. SECONDARY WOULD BE AROUND PT REYES. WILL TAKE A CLOSER LOOK
AT THIS AND POSSIBLE ISSUE A WIND ADVISORY FOR THOSE TWO SPOTS.
.PREVIOUS DISCUSSION...SATL IMAGERY AS WELL AS SFC OBS INDC PATCHY
FOG...LOCALLY DENSE IN THE NORTH BAY VALLEYS. WILL CONSIDER
ISSUING A DENSE FOG ADVISORY IF THE DENSE FOG PERSISTS...BUT NAPA
HAS A VIS OF 1SM. LOW CLOUDS ARE COMMON ACROSS MOST OF THE
DISTRICT WITH A WEAK ONSHORE FLOW. AS OF 11Z (3 AM PST) THE
GRADIENT BETWEEN SFO-SAC IS ONSHORE AT 0.8 MB AND THE GRADIENT
BETWEEN SFO-WMC IS ONSHORE AT 4.3 MB.
SATL IMAGERY IS INDC A SHORTWAVE PASSING 145W. THIS SHORTWAVE WILL
MOVE TO THE COAST TONIGHT WITH THE ASSOCIATED COLD FRONT MOVING
ACROSS THE DISTRICT OVERNIGHT. THIS SHORTWAVE WILL CUTOFF AS IT
MOVES ACROSS NORTHERN AND CENTRAL CALIFORNIA ON MONDAY. RAIN
TONIGHT WILL TAPER OFF TO SHOWERS ON MONDAY IN THE MOIST NW FLOW
AFTER THE FRONT PASSES. THERE COULD BE EVEN ENOUGH COLD AIR TO
BRING A LITTLE SNOW TO THE HIGHER PEAKS IN MONTEREY AND SAN BENITO
COUNTIES. SHOWERS COULD LINGER IN THE SOUTHERN PORTIONS OF THE
DISTRICT MONDAY NIGHT. ADDITIONALLY...BRISK NORTHWEST WINDS WILL
DEVELOP MONDAY INTO MONDAY NIGHT WITH THE STRONGEST WINDS IN THE
HILLS AND ALONG THE COAST. AS OF NOW...THE WINDS DO NOT LOOK LIKE
THEY WILL REACH ADVISORY CRITERIA.
MODELS ARE NOT IN AGREEMENT FOR THE NEXT UPSTREAM SYSTEM. THE GFS
CUTS OFF AN UPPER LOW AND DROPS IT ALONG THE COAST LATE TUESDAY
AND TUESDAY NIGHT...WHICH WOULD BRING SHOWERS TO THE DISTRICT.
THE ECMWF KEEPS THE SYSTEM IN WA TUESDAY...THEN BRINGS IT
SOUTHEAST THROUGH THE INTER MOUNTAIN WEST...WHICH WOULD KEEP THE
DISTRICT DRY. THE 00Z GFS ENSEMBLES ARE BASICALLY SPLIT BETWEEN
THE TWO SOLUTIONS. THEREFORE...HAVE KEPT A SLIGHT CHANCE OF RAIN
FOR LATE TUESDAY IN THE NORTH BAY AND ACROSS THE DISTRICT TUESDAY
NIGHT.
MODELS DO AGREE IN BUILDING A RIDGE INTO THE STATE WEDNESDAY
THROUGH FRIDAY. THIS WILL RESULT IN DRY AND MILD WEATHER. THE
ECMWF BRINGS ANOTHER SYSTEM INTO THE PACIFIC NW AND NORTHERN CA
FRIDAY NIGHT AND SATURDAY. HAVE KEPT THE CHC/SLT CHC OF RAIN FOR
THE NORTH BAY FRIDAY NIGHT AND SAT. THE 06Z GFS IS TRENDING
TOWARDS THE ECMWF SOLUTION...IF THIS TREND CONTINUES THEN POPS
MIGHT NEED TO BE INCREASED FOR THIS PERIOD.
&&
.AVIATION......AS OF 3:40 AM PST SUNDAY...AMPLE LOW LEVEL MOISTURE
REMAINS FROM YESTERDAY WITH CIGS 1-2K FEET THIS MORNING. LATEST
GUIDANCE AND TRENDS SUGGEST THAT CIGS WILL LAST WELL INTO THE
MORNING RUSH. WILL KEEP CLEARING TIMES FOR THIS AFTERNOON.
ANOTHER SYSTEM WILL MOVE IN TONIGHT WITH PRECIP SPREADING N-S
AFTER 03Z. IN ADDITION TO PRECIP...WINDS WILL RAMP UP OVERNIGHT.
CONF IS MEDIUM.
VICINITY OF KSFO...CIGS IN THE MVFR RANGE WILL KEEP MUCH OF THE
BAY COVERED THIS MORNING. WILL KEEP PREVIOUS FORECAST GOING WITH
LIFTING CIGS AFTER 21Z THIS AFTERNOON. WILL REDEVELOP CIGS AFTER
06Z TONIGHT WITH INCREASING PRECIP CHANCES. WINDS WILL RAMP UP
OVERNIGHT AS WELL WITH GUSTS OVER 20 KT ON MONDAY.
KSFO BRIDGE APPROACH....SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...MVFR CIGS THROUGH 20-22Z WITH SCT
CIGS THERE AFTER. CIGS REDEVELOP OVERNIGHT WITH RAIN POSSIBLE BY
TOMORROW MORNING.
&&
.MARINE...AS OF 3:40 AM PST SUNDAY...NORTHWEST WINDS WILL INCREASE
OVER THE COASTAL WATERS TONIGHT AS A STORM SYSTEM APPROACHES.
LATEST MODELS DEVELOP GALE FORCE WINDS OVER THE OUTER WATERS
TONIGHT AND MONDAY. OCCASIONAL GALE FORCE GUSTS WILL ALSO BE
POSSIBLE OVER THE INNER WATERS. THE STRONG AND GUSTY WINDS WILL BE
CAPABLE OF PRODUCING STEEP FRESH SWELL. IN ADDITION...THE SEA STATE
WILL INCREASE WITH WAVES GREATER THAN 10 FT DEVELOPING OVER THE
BAR. MARINERS VENTURING ON THE WATERS ON MONDAY SHOULD CHECK THE
LATEST OBSERVATIONS AND USE CAUTION.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...DENSE FOG ADVISORY...NORTH BAY VALLEYS UNTIL 11 AM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 10 AM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 10 AM
SCA...ROUGH BAR ADVISORY FOR SF BAR FROM 9 AM
&&
$$
PUBLIC FORECAST: BELL/STROBIN
AVIATION/MARINE: MM
AREA FORECAST DISCUSSION
NWS WICHITA KS
1151 AM CST SUN FEB 12 2012
.UPDATE...
MADE SOME TWEAKS EARLIER TO THE GRIDS TO INCREASE CLOUDS AND
LOWER MAXES. RUC ONCE AGAIN HAS HAD BEST HANDLE ON CLOUDS...AND
ITS TEMPERATURE FORECASTS FOR THIS AFTERNOON LOOK REASONABLE
GIVEN THE EXTENSIVE CLOUDS AND WINDS. WITH SLIGHTLY SLOWER ONSET
TO BEST LIFT/DEEPER MOISTURE...HAVE NIXED FLURRIES IN THE EXTREME
WEST SECTIONS FOR LATE THIS AFTERNOON. -HOWERTON
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MESSY AVIATION FORECAST WITH DETERIORATING CONDITIONS UNTIL LATE IN
THE FORECAST. OVERCAST VFR CEILINGS SHOULD OVERSPREAD KCNU VERY
EARLY IN THE FORECAST. MEANWHILE COMBO OF INCREASING LOW LEVEL
MOISTURE/SYNOPTIC SCALE LIFT AHEAD OF RESPECTABLE UPPER TROUGH
SHOULD GRADUALLY LOWER CEILINGS AND INCREASE CHANCES FOR
PRECIPITATION THIS EVENING/OVERNIGHT. MODEL PRECIPITATION TYPE
CONTINUE TO BE PROBLEMATIC WITH COLDEST SATURATION PERIODICALLY
DROPPING TO THE -5 TO -10C RANGE WHICH COULD RESULT IN MIXED AND
OR FREEZING PRECIPITATION. GIVEN DIFFICULTIES OF TIMING AND
UNCERTAINTY IN MODEL SOLUTIONS...HAVE OPTED TO EITHER KEEP IT SNOW
OR A RAIN AND SNOW MIX FOR NOW. PLAN IS TO AMEND IF/WHEN CHANCES
FOR FREEZING PRECIPITATION BECOME MORE LIKELY/TIMING MORE CERTAIN.
IFR CONDITIONS ARE EXPECTED TO DEVELOP AS PRECIPITATION SATURATES
LOWEST LEVELS. SOME SLIGHT IMPROVEMENT IS ANTICIPATED LATE IN THE
PERIOD. -HOWERTON
&&
.PREV DISCUSSION... /ISSUED 535 AM CST SUN FEB 12 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VFR CONDITIONS EXPECTED TODAY...THEN DETERIORATING TO MVFR IN MOST
LOCALES TONIGHT IN AREAS OF LIGHT SNOW. SURFACE HIGH PRESSURE WILL
MOVE EAST AND AWAY FROM THE REGION TODAY...AS LOW PRESSURE ALOFT
ACROSS SOUTHERN UTAH/NORTHERN ARIZONA MOVES EAST ACROSS THE
ROCKIES AND OUT ACROSS THE HIGH PLAINS TONIGHT. MOISTURE AND LIFT
IN ADVANCE OF THIS SYSTEM WILL RESULT IN AREAS OF LIGHT SNOW BY
THIS EVENING ACROSS SOUTH CENTRAL KANSAS...WHICH WILL SPREAD NORTH
AND EAST ACROSS MOST OF THE AREA LATER TONIGHT. SOUTH WINDS WILL
ALSO BECOME BRISK AND GUSTY LATER TODAY AND CONTINUE THROUGH
TONIGHT. THERE IS HIGH CONFIDENCE IN AT LEAST LOW END MVFR CAT
CIGS AND VSBYS IN THE LIGHT SNOW...WITH POTENTIAL FOR PERIODS OF
IFR CIGS AND VSBYS TOWARD THE END OF THE FORECAST VALID PERIOD.
HOWEVER WILL OMIT THIS LOWER END POSSIBILITY IN THE TAFS FOR NOW.
KED
PREV DISCUSSION... /ISSUED 340 AM CST SUN FEB 12 2012/
DISCUSSION...
FORECAST HIGHLIGHTS/CHALLENGES CONTINUE TO FOCUS AROUND SNOW &
FREEZING DRIZZLE TONIGHT-MONDAY.
TODAY:
CHILLY ARCTIC HIGH PRESSURE WILL MOVE EAST TODAY AS LOW PRESSURE
CONTINUES TO STRENGTHEN TO THE WEST...ALLOWING FOR STRENGTHENING
SOUTHERLY WINDS ACROSS THE KANSAS REGION. WITH THE STRENGTHENING
SOUTHERLY FLOW WILL COME SOMEWHAT WARMER TEMPERATURES...ALTHOUGH
WARMING WILL BE TEMPERED BY INCREASING MID/UPPER CLOUDS AHEAD OF
THE NEXT STORM SYSTEM.
TONIGHT-MONDAY:
MAIN FORECAST CONCERN WILL BE TONIGHT-MONDAY...AS A STORM SYSTEM
CURRENTLY OVER THE DESERT SOUTHWEST LIFTS NORTHEAST AND SPREADS A
VARIETY OF LIGHT WINTRY PRECIPITATION ACROSS MID-AMERICA.
ANTICIPATING LIGHT/MODERATE SNOW TO GRADUALLY SPREAD NORTHEAST
INTO SOUTH-CENTRAL KANSAS THIS EVENING...EVENTUALLY EXPANDING TO
INCLUDE MOST AREAS WEST OF THE FLINT HILLS BY MIDNIGHT...AS
800-600MB ISENTROPIC ASCENT INCREASES AHEAD OF THE STORM SYSTEM.
LIGHT/MODERATE SNOW WILL THEN MOVE INTO EASTERN KANSAS LATER
TONIGHT...GENERALLY ALONG/EAST OF THE FLINT HILLS...GRADUALLY
EXITING AREAS WEST OF THE FLINT HILLS AS A MID-LEVEL DRY SLOT
MOVES IN. HOWEVER...EVEN THOUGH THE SNOW SHOULD MOVE OUT...AM
FAIRLY CONFIDENT IN FREEZING DRIZZLE BEHIND THE SNOW...DUE TO
PERSISTENT LOW-LEVEL ISENTROPIC ASCENT/MOISTENING UNDERNEATH THE
DRY MID-LEVELS. THINKING BY MID TO LATE MORNING MONDAY...MOST OF
THE ACCUMULATING SNOW WILL HAVE MOVED EAST INTO MISSOURI...BUT A
HIGH LIKELIHOOD OF FREEZING DRIZZLE SHOULD CONTINUE ACROSS MUCH OF
THE AREA. FROM LATE MONDAY MORNING THROUGH MONDAY AFTERNOON...THE
FREEZING DRIZZLE THREAT WILL GRADUALLY WANE FROM WEST TO EAST...AS
INCREASING WEST/NORTHWEST FLOW SHOULD DECREASE LOW-LEVEL
LIFT/MOISTENING. ADDITIONALLY...TEMPERATURES SHOULD CLIMB TO NEAR
THE MID 30S MONDAY AFTERNOON...WHICH COULD CHANGE THE LIGHT
PRECIPITATION TO ALL LIQUID OVER ESPECIALLY SOUTHERN KANSAS.
GIVEN PROGRESSIVE NATURE OF THIS WAVE AND ONLY MODEST
FORCING...ANTICIPATING SNOW ACCUMULATIONS OF 1-2 INCHES ACROSS THE
AREA...LIKELY HIGHEST OVER FAR EASTERN KANSAS...WITH AMOUNTS ONE
INCH OR LESS OVER CENTRAL KANSAS. THE BIGGER CONCERN WILL LIKELY
BE THE FREEZING DRIZZLE. WHILE MAJOR ICE ACCUMULATIONS ARE NOT
ANTICIPATED...A LIGHT GLAZE APPEARS LIKELY ON TOP OF THE INCH OR
TWO OF SNOW...WHICH WILL MAKE FOR HAZARDOUS TRAVEL. THEREFORE...A
WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR GENERALLY THE EASTERN
HALF OF KANSAS THIS EVENING THROUGH LATE MONDAY AFTERNOON.
TUESDAY-SATURDAY:
DESPITE SOME MODEL DISAGREEMENT...THE GENERAL CONSENSUS SUGGESTS
ANOTHER FAST MOVING STORM SYSTEM MAY BRING SOME LIGHT
PRECIPITATION TO THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY
NIGHT. HOWEVER...THIS GO AROUND PRECIPITATION SHOULD BE
PREDOMINATELY LIQUID DUE TO WARMER TEMPERATURES...ALTHOUGH A MIX
IS POSSIBLE ESPECIALLY OVER THE NORTHERN HALF OF KANSAS.
TEMPERATURES TUESDAY AND BEYOND LOOK TO REBOUND TO NEAR OR
SLIGHTLY ABOVE SEASONAL NORMALS INTO THE 40S-50S...WITH NO MAJOR
STORM SYSTEMS ON THE HORIZON BEYOND MID-WEEK.
KLEINSASSER
AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
SOLE CONCERN THRU EARLY SUN EVENING IS THAT OF WINDS BECOMING DUE
SLY & GREATLY INCREASE...ESPECIALLY OVER CNTRL KS WHERE SUSTAINED
22-25KTS ARE LIKELY BY 17Z WITH 30-35KT GUSTS. SUCH VELOCITIES
WOULD OCCUR OVER ALL EXCEPT KCNU WHERE SUSTAINED SPEEDS SHOULD NOT
EXCEED 15KTS. CIGS TO MAINTAIN VFR STATUS WITH 6,000-8,000FT CIGS
SPREADING OVER ALL TERMINALS 17Z/18Z. FOR THE 13/00Z-13/06Z RAPID
DETERIORATION OF CIGS & VSBYS STILL ANTICIPATED OVER ALL 5
TERMINALS AS LOW PRESSURE SITUATED OVER THE WRN PLAINS CONTINUES
TO STRENGTHEN. THIS WOULD PROMOTE INCREASING WARM/MOIST ADVECTION
IN LOWEST ~8,000FT OF AIRMASS. CONFIDENCE REMAINS HIGH THAT A
WINTRY MIX WILL SPREAD NE ACROSS KS 03Z-06Z TIMEFRAME. DID NOT
PROVIDE DETAILS ON THESE LAST 3 HOURS OF FCST SO AS TO ALLOW
SUCCESSORS CHANCE TO STUDY HOW THIS PATTERN WILL EVOLVE.
EPS
FIRE WEATHER...
SOUTHERLY WINDS WILL INCREASE MARKEDLY TODAY AS LOW PRESSURE
STRENGTHENS TO THE WEST...WHICH WILL LIKELY RESULT IN A PERIOD OF
"VERY HIGH" GRASSLAND FIRE DANGER THIS AFTERNOON OVER CENTRAL
KANSAS. OTHERWISE...WIDESPREAD PRECIPITATION AND CLOUDS WILL
OVERSPREAD THE REGION TONIGHT...AND PERSIST INTO MONDAY...AS A
STORM SYSTEM APPROACHES FROM THE SOUTHWEST. SNOW ACCUMULATIONS
WILL LIKELY RANGE FROM ONE INCH OR LESS OVER CENTRAL KANSAS...TO
1-3 INCHES OVER EASTERN KANSAS. ADDITIONALLY...FREEZING DRIZZLE
IS A HIGH LIKELIHOOD. OTHERWISE...TEMPERATURES WILL GRADUALLY
REBOUND TO NEAR SEASONAL NORMALS TUESDAY AND BEYOND...WITH MAYBE
ANOTHER ROUND OF LIGHT PRECIPITATION LATE TUESDAY NIGHT INTO
WEDNESDAY NIGHT.
KLEINSASSER
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 33 27 36 25 / 10 80 50 0
HUTCHINSON 31 27 35 24 / 10 80 40 0
NEWTON 33 27 34 25 / 0 80 50 0
ELDORADO 34 27 35 24 / 0 80 50 10
WINFIELD-KWLD 33 28 37 24 / 10 80 50 0
RUSSELL 32 26 35 22 / 10 50 30 0
GREAT BEND 32 26 36 22 / 10 50 30 0
SALINA 35 27 36 23 / 10 70 40 0
MCPHERSON 33 27 35 24 / 10 70 40 0
COFFEYVILLE 37 28 36 27 / 0 90 90 10
CHANUTE 35 27 34 25 / 0 90 90 10
IOLA 35 26 34 25 / 0 90 90 10
PARSONS-KPPF 36 27 34 25 / 0 90 90 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY
FOR KSZ053-070>072-094>096-098>100.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM CST
MONDAY FOR KSZ049>052-067>069-082-083-091>093.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
151 PM EST SUN FEB 12 2012
.SYNOPSIS...
ARCTIC AIR WILL CONTINUE TO SPILL SOUTHEAST INTO THE REGION TODAY.
THE COLD AIR HAS CAUSED LAKE EFFECT SNOW SHOWERS AND FLURRIES,
THAT WILL CONTINUE INTO MONDAY. A WEAK STORM WILL MOVE THROUGH
LATE TUESDAY AND TUESDAY NIGHT WITH A WIDESPREAD LIGHT SNOW.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM...
MAIN BAND OF LE SNOW OVER CAYUGA COUNTY ACROSS WRN CORTLAND AND
ERN TOMPKINS TO BROOME AND TIOGA. HRRR SEEMS TO HAVE A GOOD HANDLE
ON THE BAND AND BEGINS TO LFT IT NEWRD IN RESPONSE TO THE APRCHG
ARCTIC FNT. THIS ALIGNS WITH CRNT RADAR TRENDS AND DVLPG WLY FLOW
SHOW ON SFC OBS. HRRR ALSO SHOWS THE BAND ALONG THE LAKE SHORE
DROPPING SWRD WITH THE FNT AND GIVING MUCH OF THE FCST AREA...ESP
ALONG AND WEST OF I81...ANOTHER GOOD BURST OF SNOW IN THE NEXT FEW
HRS. HAVE ADJUSTED THE CVRG AND INTENSITY OF THE LE FOR THIS
UPDATE...ALONG WITH A FEW OTR MINOR TWEEKS.
4 AM UPDATE...
COLD AIR MOVING INTO THE REGION HAS CONTINUED A GENERAL AREA OF
LAKE EFFECT FLURRIES ACROSS THE CWA. A BAND OF LIGHT TO MODERATE
SNOW IS COMING SOUTHEAST OFF OF LAKE CAYUGA. THIS NNW FLOW WILL
SHIFT TO NW TODAY SO NOT EXPECTING THIS TO LAST BEYOND NOON.
ANOTHER BAND IS CONTINUED TO GEORGIAN BAY INTO ROCHESTER. THIS
SHOULD EXTEND FURTHER INLAND INTO THE FINGER LAKES THIS MORNING
AND CONTINUE THIS AFTERNOON. LAKE EFFECT WILL BECOME HEAVIER
ACROSS CENTRAL NEW YORK AS A SECONDARY COLD FRONT IN SE ONTARIO
MOVES SOUTHEAST TODAY. EXPANDED THE LES ADVISORY TO INCLUDE YATES
AND CHENANGO AS WELL AS TOMPKINS AND TIOGA FOR THE CAYUGA BAND.
IN ADDITION A WIND CHILL ADVISORY CONTINUES FOR NORTHERN ONEIDA
COUNTY THIS MORNING. WIND CHILLS RIGHT AROUND MINUS FIFTEEN F
THERE. THIS AREA WILL WARM SLOWLY AS SEEN HERE. TEMPERATURES AND
DEW POINTS ON THE RISE WITH THE ADDED MOISTURE AND CLOUDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
4 AM UPDATE...
LAKE EFFECT SNOW WILL CONTINUING TONIGHT INTO MONDAY. WAA STARTS
SLOWLY WHILE THE NW FLOW SLOWLY SHIFT TO W. THIS EVENING SNOW
SHOWERS WILL BE ACROSS MOST OF THE CWA WITH THE HEAVIEST ACROSS
THE NORTHERN COUNTIES IN THE ADVISORY. CONNECTION TO GEORGIAN BAY
SHOULD CONTINUE MOST OF THE NIGHT. BY MONDAY MORNING THE LAKE SNOW
WILL BE OUT NE PA. THE FLOW WILL BE 290 INTO ONEIDA COUNTY. A LES
ADVISORY MAY BE NEEDED FOR ONEIDA FOR TONIGHT INTO MONDAY.
MONDAY UPPER LEVEL RIDGING AND WAA WILL QUICKEN. THE LOW LEVEL
SLOW GOES TO THE SW ACROSS THE ENTIRE REGION BY TUESDAY MORNING.
850 WINDS ARE STILL WEST BUT TEMPERATURES NOT ENOUGH TO CREATE
LAKE EFFECT SNOW MONDAY OVERNIGHT.
TUESDAY TEMPERATURES BACK TO NORMAL. INCREASING CLOUDS WITH MAYBE
A FLURRY LATE IN THE DAY.
A WEAK COLD FRONT WILL MOVE THROUGH TUESDAY NIGHT. SOME LIGHT SNOW
SHOWERS ARE EXPECTED WITH IT. MOISTURE AND FORCING ARE LACKING.
THE JET STREAM AND SFC LOW REMAIN WELL SOUTH OF THE REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
4AM UPDATE...
ON THE LARGE-SCALE...MEDIUM RANGE MODELS (EC/GFS/CMC) CONTINUE TO
AGREE FAIRLY WELL THIS CYCLE (00Z SUN)...THAT PACIFIC ORIGIN
DISTURBANCES WILL ZIP ACROSS THE CONUS THIS PD IN A FAST ZONAL FLOW
PATN...AND IMPACT NY/PA ABT EVERY 48 HRS...TRACKING UNDERNEATH A
FLAT ERN CANADIAN TROUGH AND OVER THE TOP OF UPR RIDGING OFF THE
SERN U.S. COAST. ALTHOUGH SOME HIGHER LAT BLOCKING DOES PRESENT
ITSELF ACROSS THE N ATLANTIC FROM TIME TO TIME THIS PD...ITS OVERALL
LACK OF PERSISTENCE SHOULD PRECLUDE ANY MAJOR STORMS FROM TAKING
SHAPE FOR THE NERN U.S. IT APPEARS THAT ANY TRUE ARCTIC AIR MASSES
WILL REMAIN N OF THE U.S./CANADIAN BORDER...ALLOWING TEMPS TO
AVERAGE CLOSE TO SEASONAL NORMS FOR MID TO LATE FEB (HIGHS IN THE
30S AND 40S).
OVERALL...VERY LTL CHANGE WAS MADE TO THE CURRENT SET OF GRIDS. IT
STILL LOOKS LIKE FAST MOVING STORM SYSTEMS WILL BRING SHOTS OF
-RA/-SN INTO WED...AGN TWDS THE END OF THE WEEK (LATE THU AND
FRI)...AND POSSIBLY JUST BEYOND THE PD (SUN INTO MON). A GENERAL
LACK OF VERY COLD AIR WILL LIMIT LAKE RESPONSES FOLLOWING ANY OF
THESE SYSTEMS.
420 PM UPDATE...HPC GRIDS FORMED BASIS OF LONG TERM
FORECAST...WHICH IS INITIALLY DOMINATED BY A SOUTHWEST FLOW THAT
HAS BEEN QUITE FAMILIAR THIS WINTER...AND SO GENERALLY ABOVE
NORMAL TEMPERATURES. HOWEVER...TOWARDS END OF THE PERIOD...THERE
IS UNCERTAINTY AS TO HOW MUCH OF A TROUGH PATTERN COULD SET UP
OVER THE NORTHEAST.
SURFACE HIGH PRESSURE GRADUALLY TAKES CHARGE TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...THOUGH WARM AIR ADVECTION WAVE ALOFT
PASSES THROUGH WITH A FAIR AMOUNT OF MOISTURE. I KEPT ONLY LOW
CHANCE POPS IN TUESDAY NIGHT...BECAUSE OF UNCERTAINTY AS TO IF ANY
PRECIPITATION CAN ACTUALLY REACH THE GROUND. IT MAY INDEED ONLY
TURN OUT TO BE ONLY AN OVERCAST SKY.
NEXT WAVE COMES LATE THURSDAY-FRIDAY...AS EITHER A NEGATIVELY
TILTED COLD FRONT OR AN OCCLUDED FRONT. ECWMF PREFERS MORE OF AN
INSTANT OCCLUSION SCENARIO AS OHIO VALLEY LOW APPROACHES WESTERN NY
THURSDAY EVENING...BUT NEW LOW ALSO DEVELOPS AND STRENGTHENS
OFFSHORE. THAT COULD POTENTIALLY YIELD A FAIR SYNOPTIC SNOW FOR
THE AREA...YET WE COULD ALSO QUICKLY GET INTO DRY SLOT WHICH WOULD
LIMIT AMOUNTS. GFS WAITS UNTIL WELL AFTER FRONT PASSES...BEFORE
ANY COASTAL SURFACE REFLECTION OF NEW LOW BECOMES APPARENT. IN
THIS CASE...PRECIPITATION WOULD BE MORE OF A QUICK SHOT...WITH
MORE TIME FOR WARM AIR TO BE INVOLVED AHEAD OF THE FRONT...SO
PRECIPITATION TYPE IS IN QUESTION. GIVEN ALL OF THESE
UNCERTAINTIES...FIGURED MID CHANCE RANGE POPS OFFERED BY HPC
SUFFICED WELL...AS IT LOOKS UNSETTLED AND WE JUST HAVE TO SORT OUT
THE DETAILS IN COMING DAYS.
GFS DOES BRING A BRIEF PIECE OF COLDER AIR IN BY NEXT
SATURDAY...WITH DEEPER YET ALSO TEMPORARY UPPER TROUGH. I PLACED
SOME CHANCE POPS IN CENTRAL NEW YORK FOR POSSIBLE LAKE EFFECT AT
THAT TIME.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
130 PM UPDATE...A BAND OF HEAVIER SNOW SQUALLS IS IN THE PROCESS
OF CLEARING THE SOUTHERN TIER OF NY TERMINALS. SOME IFR VSBYS ARE
STILL POSSIBLE FOR ANOTHER HOUR OR SO AT KELM AND KBGM. FARTHER
SOUTH AT KAVP IF THE BAND HOLDS TOGETHER A BRIEF PERIOD OF IFR
VSBYS ARE POSSIBLE BETWEEN 20Z AND 22Z.
ELSEWHERE MAINLY VFR VSBYS IN LIGHT FLURRIES...WITH PERIODS OF
MVFR CIGS. TOWARD EVENING AS THE FLOW BECOMES MORE
ESTABLISHED...ANOTHER BAND OF LAKE EFFECT SNOW WILL SET UP ON A
300 DEGREE FLOW. INITIALLY THIS MAY PRODUCE SOME IFR VSBYS AT
KITH AND KBGM...ALONG WITH KSYR...BUT ALL THREE TERMINALS MAY JUST
BE ON THE EDGE OF THE ACTUAL BAND ITSELF. AFTER MIDNIGHT AS THE
FLOWS BACKS JUST A BIT TOWARD THE WEST-NORTHWEST...KSYR AND KRME
WILL BE THE TWO TERMINALS THAT WILL BE UNDER THE GUN FOR IFR AND
LIFR VSBYS IN HEAVY LAKE EFFECT SNOW. IMPROVEMENT IS NOT EXPECTED
HERE UNTIL NEAR DAYBREAK AT KSYR AND MID MONDAY MORNING AT KRME.
ELSEWHERE...THE NORTHWEST FLOW ITSELF WILL PRODUCE PERIODS OF MVFR
CIGS OVERNIGHT WITH KITH AND KBGM BEING THE MOST LIKELY TERMINALS
FOR THIS TO OCCUR AND KELM BEING THE LEAST LIKELY. SLOW
IMPROVEMENT TO VFR IS POSSIBLE BY MID-MONDAY MORNING.
NORTHWEST WINDS AROUND 12 TO 15 KTS WITH GUSTS TO 25 KTS THROUGH
THIS EVENING. OVERNIGHT NORTHWEST WINDS AROUND 12KTS...DIMINISHING
TO UNDER 10 KTS MONDAY AFTERNOON.
.OUTLOOK...
TUE/WED...MVFR/IFR PSBL AT ALL TAF SITES IN LGT SNOW.
THUR...VFR.
FRI...MVFR POSSIBLE IN RAIN/SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST MONDAY FOR NYZ015>018-
025-036-044-045-055.
&&
$$
SYNOPSIS...TAC
NEAR TERM...DGM/TAC
SHORT TERM...TAC
LONG TERM...MLJ/MDP
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1245 PM EST SUN FEB 12 2012
.SYNOPSIS...
MUCH COLDER AIR WILL CONTINUE TO POUR IN THE REGION THROUGH THE
REMAINDER OF THE WEEKEND. SNOW AND LOCALIZED LAKE EFFECT SNOWS
SOUTHEAST OF THE LAKES WILL CONTINUE THROUGH TONIGHT. ANY
LINGERING SNOW SHOWERS SOUTHEAST OF THE LAKES MONDAY MORNING WILL
END AS HIGH PRESSURE BUILDS INTO THE REGION. ANOTHER WEAK SYSTEM
MAY BRING SOME LIGHT SNOW ON TUESDAY AS TEMPERATURES MODERATE TO
A LITTLE ABOVE AVERAGE AGAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
BAND OF INTENSE LAKE SNOWS DROPPING SOUTH IMPACTING THE NIAGARA
FALLS/BUFFALO AREAS OVER TO ROCHESTER LATE THIS MORNING. THIS BAND
DROPPING SNOWFALL RATES UP TO TWO INCHES PER HOUR. THIS BAND WILL
CONTINUE TO SINK SOUTHWARD BUT LIKELY WEAKEN SOMEWHAT AS IT MOVES
AWAY FROM LAKE INFLUENCES...WHICH IS SUPPORTED BY LATEST HRRR.
LATEST HRRR AND WRF SUGGESTING WEAKER MULTIPLE BANDS WILL CONTINUE
TO IMPACT BOTH LAKES THROUGH THE AFTERNOON. LAKE SNOW HEADLINES WILL
REMAIN INTACT WITH ADDITIONAL AMOUNTS THROUGH THIS AFTERNOON IN THE
2-4/3-5 INCH RANGE IN FAVORED NORTHWEST FLOW AREAS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AT THE START OF THE PERIOD MONDAY MORNING A LAKE EFFECT BAND WILL
STILL BE ONGOING SOUTHEAST OF LAKE ONTARIO. INSTABILITY WILL BE ON
THE WANE...WITH LAKE INDUCED EQUILIBRIUM LEVELS AROUND 6K FEET.
DESPITE THE WEAKENING INSTABILITY...STILL FAVORABLE SNOW GROWTH AND
LONG FETCH SHOULD KEEP A DECENT BAND GOING MONDAY MORNING AS IT
LIFTS ACROSS OSWEGO COUNTY TOWARD THE TUG HILL WITH A FEW INCHES
POSSIBLE. BY MIDDAY LAKE INDUCED INSTABILITY BEGINS TO WEAKEN
FURTHER...AND THAT COMBINED WITH DIMINISHING SYNOPTIC SCALE MOISTURE
AND INCREASING SHEAR WILL BREAK THE BAND APART INTO SCATTERED SNOW
SHOWERS ACROSS THE TUG HILL REGION...THEN END ALTOGETHER BY EARLY
MONDAY EVENING. OFF LAKE ERIE EXPECT LAKE EFFECT TO BE OVER BY 12Z
MONDAY.
OTHERWISE MOST AREAS SHOULD SEE A DECENT AMOUNT OF SUNSHINE ON
MONDAY OUTSIDE OF THE LAKE ONTARIO LAKE EFFECT. MODERATING AIRMASS
SHOULD BRING HIGHS BACK VERY CLOSE TO AVERAGE...LOW 30S ON THE LAKE
PLAINS AND UPPER 20S HIGHER TERRAIN.
LATE MONDAY NIGHT THROUGH TUESDAY OUR ATTENTION TURNS TO THE NEXT
SYNOPTIC SCALE SYSTEM. A MID LEVEL TROUGH EJECTING OUT OF THE PLAINS
WILL GRADUALLY WEAKEN AS IT MOVES EAST THROUGH THE OHIO VALLEY AND
MID ATLANTIC...BUT STILL MAINTAIN ENOUGH FORCING AND DEEP LAYER WARM
ADVECTION/MOISTURE TO SUPPORT A BROAD AREA OF LIGHT SNOW ENTERING
WESTERN NY LATE MONDAY NIGHT OR TUESDAY MORNING...THEN OVERSPREADING
THE REST OF THE AREA ON TUESDAY. AMOUNTS SHOULD BE VERY LIGHT WITH
THIS...PERHAPS AN INCH OR TWO IN SOME SPOTS. TEMPERATURES WARM ABOVE
FREEZING DURING THE AFTERNOON IN MOST LOCATIONS WHICH WILL INHIBIT
ANY FURTHER ACCUMULATION.
THE LIGHT SNOW GRADUALLY TAPERS OF TUESDAY NIGHT AS THE WEAKENING
SYSTEM PULLS OUT TO SEA...BUT WILL LEAVE BEHIND PLENTY OF CLOUD
COVER AS LOW LEVEL MOISTURE BECOMES TRAPPED BENEATH A STEEPENING
INVERSION ALOFT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY BROAD HIGH PRESSURE WILL EXTEND FROM THE OHIO VALLEY NORTH
AND EASTWARD ACROSS THE EASTERN GREAT LAKES REGION. LOW LEVEL
MOISTURE REMAINS PLENTIFUL IN THE LOWER LAYER OF THE
ATMOSPHERE...WHILE ALOFT BOTH THE GFS AND ECMWF HAVE A WEAK SHORT
WAVE CROSSING THE REGION. WILL HAVE LOW CHC POPS WEDNESDAY FOR LIGHT
SNOW...AND AS TEMPERATURE PROFILES WARM...THIS COULD MIX WITH LIGHT
DRIZZLE OR RAIN.
AS MOISTURE WANES SOME BEHIND THE WEAK UPPER LEVEL SHORT WAVE EXPECT
THE SCATTERED LIGHT PRECIPITATION TO COME TO AN END WEDNESDAY
NIGHT...THOUGH MOISTURE WILL STILL REMAIN HIGH ENOUGH TO SUPPORT
PLENTY OF CLOUDS THROUGH THE NIGHT.
THURSDAY AND FRIDAY PRECIPITATION WILL RETURN TO THE REGION AS BOTH
THE 00Z GFS AND ECMWF WITH FAIRLY GOOD SUPPORT FROM THE GEFS HAVE A
PACIFIC SHORTWAVE EJECTING OUT OF THE CENTRAL PLAINS AND TOWARD THE
LOWER LAKES.
INITIALLY RAIN MAY MIX IN THURSDAY ACROSS THE REGION...BUT WITH CAA
BEHIND THE SHORT WAVE A TRANSITION TO ALL SNOW THURSDAY NIGHT AND
FRIDAY IS LIKELY. WHETHER THESE SHORTWAVES PHASE OR NOT WILL LIKELY
IMPACT THE TRACK OF THE STORM...WITH A PHASED SOLUTION TAKING A
STORM PATH TO OUR WEST AND NORTH WITH MILD CONDITIONS THURSDAY. IF
THESE SHORTWAVE DO NOT PHASE...A LESS AMPLIFIED FLOW IS EXPECTED
HOLDING WARMER AIR TO THE SOUTH AND PRECIPITATION FAVORING MORE SNOW
THAN RAIN.
TEMPERATURES ALOFT AT 850 HPA DROP TO -8 TO -10C ON THE GLOBAL
MODELS...AND LAKE ENHANCED SNOW POSSIBLE FRIDAY AND FRIDAY NIGHT AS
THIS SYSTEM PULLS AWAY. BEING DAYS 5 AND 6 WILL STAY WITH CHC POPS
FOR THE WORDING...AND FINE TUNE AS WE DRAW CLOSER TO THE EVENT TIME.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
COLD NORTHWEST FLOW CONTINUING TO GENERATE MULTIPLE BANDS OF LAKE
EFFECT SNOW OFF BOTH LAKE ERIE AND LAKE ONTARIO. OUTSIDE THE LAKE
BANDS VFR CONDITIONS EXIST. WITHIN THE LAKE BANDS...IFR
VSBYS/CIGS ARE COMMON. WINDS HAVE GRADUALLY DROPPED OFF THIS
AFTERNOON ALLOWING BLOWING SNOW TO BECOME LESS OF AN IMPACT.
HIGH PRESSURE BUILDING INTO THE REGION TONIGHT AND MONDAY WILL
GRADUALLY LESSEN THE LAKE BANDS. HOWEVER...A SIGNIFICANT LAKE BAND
PRODUCING IFR CONDITIONS IS EXPECTED TO DEVELOP AROUND THE KFZY/KSYR
AREA AND LIFT NORTHWARD TOWARD KART THROUGH MONDAY MORNING
OUTLOOK...
MONDAY NIGHT...MAINLY VFR.
TUESDAY...MVFR WITH SNOW LIKELY.
WEDNESDAY...MAINLY VFR.
THURSDAY...MVFR WITH RAIN/SNOW LIKELY.
FRIDAY...MVFR WITH CHC SNOW.
&&
.MARINE...
STRONG HIGH PRESSURE HAS SETTLED ACROSS THE CENTRAL PLAINS AND WILL
BUILD NORTHWARD ACROSS THE LAKES THROUGH THE REMINDER OF THE
WEEKEND. THE PRESSURE GRADIENT ACROSS THE LAKES WILL REMAIN TIGHT
ENOUGH TODAY TO MAINTAIN SMALL CRAFT CONDITIONS ON THE LAKES THROUGH
TONIGHT AND INTO MONDAY. HEAVY FREEZING SPRAY IS STILL POSSIBLE ACROSS
LAKE ERIE THROUGH 10AM THIS MORNING THEN TEMPERATURES RISE HIGH
ENOUGH TO NOT ALLOW CONCERN FOR THESE CONDITIONS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
MONDAY FOR NYZ005-006.
LAKE EFFECT SNOW WARNING UNTIL 6 AM EST MONDAY FOR NYZ004.
LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ003.
LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ002.
LAKE EFFECT SNOW ADVISORY UNTIL 6 PM EST THIS EVENING FOR
NYZ012-019-020-085.
LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST MONDAY FOR NYZ014.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR
LOZ042>045.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...TMA
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK/THOMAS
AVIATION...TMA
MARINE...HITCHCOCK/SMITH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
546 PM EST SUN FEB 12 2012
.SYNOPSIS...
THE COLD AIR WILL SLIDE OFF THE EAST COAST TONIGHT AND MONDAY.
THE FLOW WILL BECOME NEARLY ZONAL AND TEMPERATURES WILL RETURN TO
NEAR NORMAL. ANOTHER TROUGH IS FORECAST TO DEVELOP OVER THE
EASTERN UNITED STATES LATER IN THE WEEK WITH SOME ADDITIONAL COLD
AIR.
&&
.NEAR TERM /THROUGH MONDAY/...
WEAK SFC TROUGH DROPPING SOUTH THROUGH THE NERN HALF OF THE AREA
THIS EVENING WILL CREATE A BRIEF PD OF ENHANCED SNOW SHOWERS...BUT
SHOULD NOT AMOUNT TO MORE THAN A DUSTING TO AN INCH IN MOST
PLACES. CURR HRRR RUN EXTENDS THE FORCING AND SOME VERY LIGHT
ACCUMS INTO SCHUYLKILL CO IN ANOTHER HOUR OR TWO. DOWNSLOPING
SHOULD REDUCE THE INTENSITY OF ANY NOW TO LITTLE MORE THAN
FLURRIES AS IT COMES OFF OF BLUE MTN INTO THE LOWER SUSQ. WINDS
ARE GUSTY ALONG THE LEADING EDGE OF THE TROUGH AS THE SHOWERS MOVE
IN. SO...WILL BUMP WINDS UP ALONG WITH POPS THERE IN THE NE FOR
THE FIRST FEW HRS OF THE FCST. BUT...THE TROUGH WASHES OUT AND
SUNSET WILL ALSO DIMINISH THE LLVL INSTABILITY. EVENING WILL BRING
LESS MIXING ON THE WHOLE AND THE GRADIENT SLACKENS AS
WELL...SPELLING A CERTAIN END TO THE WORST OF THE GUSTY WINDS.
THE WINT WX ADVY FOR THE SNOW BELT IS WEAK BUT WILL KEEP IT
RUNNING FOR NOW...AS THE SNOW IS STILL GOING. THERE SHOULD NOT BE
ENOUGH SNOW /3+ INCHES/ OVERNIGHT TO WARRANT KEEPING THE ADVY
GOING. WINDS OVER OH AND A PEEK AT KCLE RADAR ALREADY HINT AT THE
GRADUAL REDUCTION IN MOISTURE COMING OFF THE LAKES INTO PA THAT
SHOULD OCCUR DURING THE NIGHT. EXPECT THE WRN AND NRN MTS TO STAY
MOSTLY CLOUDY AND STILL HAVE SOME FLURRIES ALL NIGHT...WITH MOST
GUIDANCE POINTING TO SOME LIGHT QPF THROUGH 12Z. TEMPS TONIGHT
WILL NOT BE AS COLD AS LAST NIGHT AS 8H TEMPS RISE SLIGHTLY IN THE
EAST AND SIGNIFICANTLY IN THE WEST.
WILL ONLY MENTION A FLURRY IN THE WEST FOR A FEW HRS MON AM...AND
KEEP IT DRY AND SUNNY ELSEWHERE. ANY SIG HIGH CLOUDS FROM THE NEXT
SYSTEM HEADING TO US ON THE RELATIVELY MILD WESTERLY FLOW SHOULD
HOLD OFF UNTIL AFTER SUNSET MONDAY. WINDS DON/T GO LIGHT IN MOST
PLACES ON MONDAY SINCE THE CENTER OF THE SFC HIGH WILL BE TOO FAR
TO THE SOUTH. MAXES WILL RUN IN THE NEAR NORMALS MONDAY WITH 8H
TEMPS AROUND -4C IN THE AFTN WITH PLENTY OF SUNSHINE OVER MOST OF
THE AREA.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
U.S./EURO OPERATIONAL MODELS AND ENSEMBLES SHOW A RELATIVELY WEAK
SFC...AND FLAT UPPER WAVE HEADING EAST FROM THE OHIO VALLEY
MONDAY NIGHT...HELPING TO THICKEN UP CLOUDS AND SPREAD SOME LIGHT
SNOW SHOWERS ACROSS THE WRN MTNS AFTER MIDNIGHT. A FEW PERIODS OF
LIGHT SNOW /OR MIXED PRECIP AT ELEVATIONS AOB 1000 FT MSL/ ARE
LIKELY ON TUESDAY THROUGH EARLY TUESDAY NIGHT. 12Z SHORT RANGE
OPERATIONAL MODELS AND 09Z SREF MEAN APPEARS TO INDICATE AROUND
0.25 INCH OF LEQ PRECIP...AND THE POTENTIAL FOR 1-2 INCHES OF SNOW
ACCUM ACROSS THE CENTRAL AND NRN ZONES...WITH LESS THAN ONE INCH OF
SLUSHY SNOW THROUGHOUT MUCH OF THE SUSQ VALLEY.
DAYTIME TEMPS TUESDAY WILL BE WARM ENOUGH UNDER THE LATE FEBRUARY
SUN TO MELT MUCH OF WAT FALLS THROUGHOUT THE VALLEYS OF THE CENTRAL
AND SOUTH. MAX TEMPS WILL VARY FROM THE LOWER TO MID 30S ACROSS THE
MTNS...TO THE LOWER 40S IN THE SE VALLEYS.
MINS TUESDAY NIGHT /UNDER NW FLOW AFTER THE WAVE EXITS THE MID
ATLANTIC COAST/ WILL RANGE THROUGH THE 20S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A BRIEF PERIOD OF LIGHTER WIND...AND AT LEAST PARTIAL CLEARING
WEDNESDAY AS A RIDGE OF HIGH PRESSURE BUILDS EAST ACROSS THE STATE.
AFTERNOON TEMPS WED WILL CLIMB TO THE UPPER 30S AND LOWER 40S IN THE
MTNS...AND MID TO PERHAPS UPPER 40S IN THE SE PIEDMONT...WHICH WILL
BE 5-7F ABOVE NORMAL.
THE SECOND...AND LIKELY MORE SIGNIFICANT PRECIP EVENT OF THE WEEK
AHEAD ARRIVES ON THURSDAY...AS A MODERATELY AMPLIFIED WAVE /THAT
WILL BRING SOME SIGNIF SNOWS TO THE ROCKIES/ HEADS NE ACROSS THE
PLAINS STATES AND MIDWEST...AND PHASES WITH SOME NRN STREAM ENERGY.
THE SFC LOW SHOULD TAKE A TRACK ACROSS THE CENTRAL OR ERN GLAKES
LATE THURSDAY AND THU NIGHT.
MODEL SOUNDINGS AND LLVL WET BULB STRUCTURE FAVORS AN INITIAL PERIOD
OF SNOW OR MIXED PRECIP...CHANGING TO MIXED PRECIP OR RAIN IN THE
AFTERNOON AND EVENING AS WARMER AIR ALOFT SURGES NE INTO THE REGION.
THE TRICKIER PART OF THE FCST FOR THURSDAY INTO THURSDAY NIGHT IS
THE DEGREES OF SHALLOW...COLD AIR DAMMING TO THE EAST OF THE
ALLEGHENY PLATEAU. WILL STILL FAVOR TEMPS CLIMBING TO ABOUT 5 DEG F
ABOVE NORMAL LATER IN THE DAY THURSDAY AS THE MAIN WARM FRONTAL
PRECIP SHIELD LIFTS NORTH OF THE REGION...WITH THE SFC CFRONT STILL
LOCATED TO OUR WEST ACROSS OHIO.
DRIER AND COOLER WEATHER PATTERN SETS IN FOR FRIDAY THROUGH MONDAY
WITH ISOLATED TO SCATTERED...MAINLY MTN SNOW SHOWERS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
COLD NW FLOW PRODUCING OROGRAPHICALLY ENHANCED LAKE EFFECT SNOW
OVR THE ALLEGHENY MTNS EARLY THIS EVENING WITH IFR VSBYS AT BFD
AND JST. DOWNWIND OF THE MTNS...GENERALLY VFR CONDS NOTED.
IMPROVING VSBYS EXPECTED OVERNIGHT...AS APPROACHING HIGH
PRES/LOWERING INVERSION HGTS CAUSES SHSN TO TAPER OFF.
HOWEVER...MVFR CIGS ARE LIKELY TO LINGER AT BFD/JST THRU MON
MORNING.
OTHER AVIATION CONCERN IS THE STRONG/GUSTY NW WINDS BUFFETING THE
AREA. SUSTAINED WINDS WILL ONLY SLOWLY DIMINISH OVERNIGHT DUE TO
STRONG PRES GRADIENT REMAINING BTWN STORM OVR THE CANADIAN
MARITIMES AND APPROACHING HIGH PRES. HOWEVER...THE 25-30KT GUSTS
SHOULD ONLY LAST THRU EARLY THIS EVENING.
OTHER THAN AM MVFR CIGS/FLURRIES OVR THE W MTNS...EXPECT MAINLY
SUNNY SKIES MONDAY AS SFC HIGH PASSES SOUTH OF PA. WEST WINDS
WILL REMAIN ACTIVE MONDAY...WITH MDL SOUNDINGS INDICATING FREQUENT
GUSTS IN THE 20-25KT RANGE.
OUTLOOK...
TUE...MVFR IN -SN POSSIBLE.
WED...MAINLY VFR...WRN MTS MAY DIP TO MVFR IN SHSN.
THU...MVFR TO IFR IN SHRA/SN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ004-
005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...LAMBERT
LONG TERM...LAMBERT
AVIATION...DANGELO/FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
358 PM EST SUN FEB 12 2012
.SYNOPSIS...
THE COLD AIR WILL SLIDE OFF THE EAST COAST TONIGHT AND MONDAY.
THE FLOW WILL BECOME NEARLY ZONAL AND TEMPERATURES WILL RETURN TO
NEAR NORMAL. ANOTHER TROUGH IS FORECAST TO DEVELOP OVER THE
EASTERN UNITED STATES LATER IN THE WEEK WITH SOME ADDITIONAL COLD
AIR.
&&
.NEAR TERM /THROUGH MONDAY/...
WEAK SFC TROUGH DROPPING SOUTH THROUGH THE NERN HALF OF THE AREA
THIS EVENING WILL CREATE A BRIEF PD OF ENHANCED SNOW SHOWERS...BUT
SHOULD NOT AMOUNT TO MORE THAN A DUSTING TO AN INCH IN MOST
PLACES. CURR HRRR RUN EXTENDS THE FORCING AND SOME VERY LIGHT
ACCUMS INTO SCHUYLKILL CO IN ANOTHER HOUR OR TWO. DOWNSLOPING
SHOULD REDUCE THE INTENSITY OF ANY NOW TO LITTLE MORE THAN
FLURRIES AS IT COMES OFF OF BLUE MTN INTO THE LOWER SUSQ. WINDS
ARE GUSTY ALONG THE LEADING EDGE OF THE TROUGH AS THE SHOWERS MOVE
IN. SO...WILL BUMP WINDS UP ALONG WITH POPS THERE IN THE NE FOR
THE FIRST FEW HRS OF THE FCST. BUT...THE TROUGH WASHES OUT AND
SUNSET WILL ALSO DIMINISH THE LLVL INSTABILITY. EVENING WILL BRING
LESS MIXING ON THE WHOLE AND THE GRADIENT SLACKENS AS
WELL...SPELLING A CERTAIN END TO THE WORST OF THE GUSTY WINDS.
THE WINT WX ADVY FOR THE SNOW BELT IS WEAK BUT WILL KEEP IT
RUNNING FOR NOW...AS THE SNOW IS STILL GOING. THERE SHOULD NOT BE
ENOUGH SNOW /3+ INCHES/ OVERNIGHT TO WARRANT KEEPING THE ADVY
GOING. WINDS OVER OH AND A PEEK AT KCLE RADAR ALREADY HINT AT THE
GRADUAL REDUCTION IN MOISTURE COMING OFF THE LAKES INTO PA THAT
SHOULD OCCUR DURING THE NIGHT. EXPECT THE WRN AND NRN MTS TO STAY
MOSTLY CLOUDY AND STILL HAVE SOME FLURRIES ALL NIGHT...WITH MOST
GUIDANCE POINTING TO SOME LIGHT QPF THROUGH 12Z. TEMPS TONIGHT
WILL NOT BE AS COLD AS LAST NIGHT AS 8H TEMPS RISE SLIGHTLY IN THE
EAST AND SIGNIFICANTLY IN THE WEST.
WILL ONLY MENTION A FLURRY IN THE WEST FOR A FEW HRS MON AM...AND
KEEP IT DRY AND SUNNY ELSEWHERE. ANY SIG HIGH CLOUDS FROM THE NEXT
SYSTEM HEADING TO US ON THE RELATIVELY MILD WESTERLY FLOW SHOULD
HOLD OFF UNTIL AFTER SUNSET MONDAY. WINDS DON/T GO LIGHT IN MOST
PLACES ON MONDAY SINCE THE CENTER OF THE SFC HIGH WILL BE TOO FAR
TO THE SOUTH. MAXES WILL RUN IN THE NEAR NORMALS MONDAY WITH 8H
TEMPS AROUND -4C IN THE AFTN WITH PLENTY OF SUNSHINE OVER MOST OF
THE AREA.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
U.S./EURO OPERATIONAL MODELS AND ENSEMBLES SHOW A RELATIVELY WEAK
SFC...AND FLAT UPPER WAVE HEADING EAST FROM THE OHIO VALLEY
MONDAY NIGHT...HELPING TO THICKEN UP CLOUDS AND SPREAD SOME LIGHT
SNOW SHOWERS ACROSS THE WRN MTNS AFTER MIDNIGHT. A FEW PERIODS OF
LIGHT SNOW /OR MIXED PRECIP AT ELEVATIONS AOB 1000 FT MSL/ ARE
LIKELY ON TUESDAY THROUGH EARLY TUESDAY NIGHT. 12Z SHORT RANGE
OPERATIONAL MODELS AND 09Z SREF MEAN APPEARS TO INDICATE AROUND
0.25 INCH OF LEQ PRECIP...AND THE POTENTIAL FOR 1-2 INCHES OF SNOW
ACCUM ACROSS THE CENTRAL AND NRN ZONES...WITH LESS THAN ONE INCH OF
SLUSHY SNOW THROUGHOUT MUCH OF THE SUSQ VALLEY.
DAYTIME TEMPS TUESDAY WILL BE WARM ENOUGH UNDER THE LATE FEBRUARY
SUN TO MELT MUCH OF WAT FALLS THROUGHOUT THE VALLEYS OF THE CENTRAL
AND SOUTH. MAX TEMPS WILL VARY FROM THE LOWER TO MID 30S ACROSS THE
MTNS...TO THE LOWER 40S IN THE SE VALLEYS.
MINS TUESDAY NIGHT /UNDER NW FLOW AFTER THE WAVE EXITS THE MID
ATLANTIC COAST/ WILL RANGE THROUGH THE 20S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A BRIEF PERIOD OF LIGHTER WIND...AND AT LEAST PARTIAL CLEARING
WEDNESDAY AS A RIDGE OF HIGH PRESSURE BUILDS EAST ACROSS THE STATE.
AFTERNOON TEMPS WED WILL CLIMB TO THE UPPER 30S AND LOWER 40S IN THE
MTNS...AND MID TO PERHAPS UPPER 40S IN THE SE PIEDMONT...WHICH WILL
BE 5-7F ABOVE NORMAL.
THE SECOND...AND LIKELY MORE SIGNIFICANT PRECIP EVENT OF THE WEEK
AHEAD ARRIVES ON THURSDAY...AS A MODERATELY AMPLIFIED WAVE /THAT
WILL BRING SOME SIGNIF SNOWS TO THE ROCKIES/ HEADS NE ACROSS THE
PLAINS STATES AND MIDWEST...AND PHASES WITH SOME NRN STREAM ENERGY.
THE SFC LOW SHOULD TAKE A TRACK ACROSS THE CENTRAL OR ERN GLAKES
LATE THURSDAY AND THU NIGHT.
MODEL SOUNDINGS AND LLVL WET BULB STRUCTURE FAVORS AN INITIAL PERIOD
OF SNOW OR MIXED PRECIP...CHANGING TO MIXED PRECIP OR RAIN IN THE
AFTERNOON AND EVENING AS WARMER AIR ALOFT SURGES NE INTO THE REGION.
THE TRICKIER PART OF THE FCST FOR THURSDAY INTO THURSDAY NIGHT IS
THE DEGREES OF SHALLOW...COLD AIR DAMMING TO THE EAST OF THE
ALLEGHENY PLATEAU. WILL STILL FAVOR TEMPS CLIMBING TO ABOUT 5 DEG F
ABOVE NORMAL LATER IN THE DAY THURSDAY AS THE MAIN WARM FRONTAL
PRECIP SHIELD LIFTS NORTH OF THE REGION...WITH THE SFC CFRONT STILL
LOCATED TO OUR WEST ACROSS OHIO.
DRIER AND COOLER WEATHER PATTERN SETS IN FOR FRIDAY THROUGH MONDAY
WITH ISOLATED TO SCATTERED...MAINLY MTN SNOW SHOWERS.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
TYPICAL NW FLOW MEANS IFR/OCNL MVFR OVER THE WRN SITES OF BFD AND
JST. EXPECT VFR CIGS AT AOO. A BRIEF PD OF MVFR CIGS AND MVFR OR
EVEN IFR VSBY IS POSSIBLE BEFORE 00Z AT UNV AND IPT AS A WEAK SFC
TROUGH PUSHES ACROSS. THIS TROUGH COULD ALSO ENHANCE THE WINDS TO
20G30KT. VFR IN THE SERN SITES. THE GUSTY WINDS ELSEWHERE WILL
CONTINUE FOR THE EARLY EVENING WITH 40+ KT FLOW JUST 2-3KFT
ALOFT. THE GUSTS WILL DIMINISH SLIGHTLY THIS EVENING WITH SHALLOW-
ER MIXING AND THE HIGH BUILD TO OUR SOUTH. EXPECT THE WRN
TERMINALS TO STAY LOW IN VSBY AND CIGS THROUGH MOST OF THE NIGHT
AND FLURRIES COULD LAST INTO 12-15Z MONDAY. BIG SFC HIGH TO THE S
WILL MAKE FOR SUNNY SKIES OVER MOST OF THE AREA.
OUTLOOK...
TUE...MVFR IN -SN POSSIBLE.
WED...MAINLY VFR...WRN MTS MAY DIP TO MVFR IN SHSN.
THU...MVFR TO IFR IN SHRA/SN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ004-
005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...LAMBERT
LONG TERM...LAMBERT
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
259 PM EST SUN FEB 12 2012
.SYNOPSIS...
THE COLD AIR WILL SLIDE OFF THE EAST COAST TONIGHT AND MONDAY.
THE FLOW WILL BECOME NEARLY ZONAL AND TEMPERATURES WILL RETURN TO
NEAR NORMAL. ANOTHER TROUGH IS FORECAST TO DEVELOP OVER THE
EASTERN UNITED STATES LATER IN THE WEEK WITH SOME ADDITIONAL COLD
AIR.
&&
.NEAR TERM /THROUGH MONDAY/...
WEAK SFC TROUGH DROPPING SOUTH THROUGH THE NERN HALF OF THE AREA
THIS EVENING WILL CREATE A BRIEF PD OF ENHANCED SNOW SHOWERS...BUT
SHOULD NOT AMOUNT TO MORE THAN A DUSTING TO AN INCH IN MOST
PLACES. CURR HRRR RUN EXTENDS THE FORCING AND SOME VERY LIGHT
ACCUMS INTO SCHUYLKILL CO IN ANOTHER HOUR OR TWO. DOWNSLOPING
SHOULD REDUCE THE INTENSITY OF ANY NOW TO LITTLE MORE THAN
FLURRIES AS IT COMES OFF OF BLUE MTN INTO THE LOWER SUSQ. WINDS
ARE GUSTY ALONG THE LEADING EDGE OF THE TROUGH AS THE SHOWERS MOVE
IN. SO...WILL BUMP WINDS UP ALONG WITH POPS THERE IN THE NE FOR
THE FIRST FEW HRS OF THE FCST. BUT...THE TROUGH WASHES OUT AND
SUNSET WILL ALSO DIMINISH THE LLVL INSTABILITY. EVENING WILL BRING
LESS MIXING ON THE WHOLE AND THE GRADIENT SLACKENS AS
WELL...SPELLING A CERTAIN END TO THE WORST OF THE GUSTY WINDS.
THE WINT WX ADVY FOR THE SNOW BELT IS WEAK BUT WILL KEEP IT
RUNNING FOR NOW...AS THE SNOW IS STILL GOING. THERE SHOULD NOT BE
ENOUGH SNOW /3+ INCHES/ OVERNIGHT TO WARRANT KEEPING THE ADVY
GOING. WINDS OVER OH AND A PEEK AT KCLE RADAR ALREADY HINT AT THE
GRADUAL REDUCTION IN MOISTURE COMING OFF THE LAKES INTO PA THAT
SHOULD OCCUR DURING THE NIGHT. EXPECT THE WRN AND NRN MTS TO STAY
MOSTLY CLOUDY AND STILL HAVE SOME FLURRIES ALL NIGHT...WITH MOST
GUIDANCE POINTING TO SOME LIGHT QPF THROUGH 12Z. TEMPS TONIGHT
WILL NOT BE AS COLD AS LAST NIGHT AS 8H TEMPS RISE SLIGHTLY IN THE
EAST AND SIGNIFICANTLY IN THE WEST.
WILL ONLY MENTION A FLURRY IN THE WEST FOR A FEW HRS MON AM...AND
KEEP IT DRY AND SUNNY ELSEWHERE. ANY SIG HIGH CLOUDS FROM THE NEXT
SYSTEM HEADING TO US ON THE RELATIVELY MILD WESTERLY FLOW SHOULD
HOLD OFF UNTIL AFTER SUNSET MONDAY. WINDS DON/T GO LIGHT IN MOST
PLACES ON MONDAY SINCE THE CENTER OF THE SFC HIGH WILL BE TOO FAR
TO THE SOUTH. MAXES WILL RUN IN THE NEAR NORMALS MONDAY WITH 8H
TEMPS AROUND -4C IN THE AFTN WITH PLENTY OF SUNSHINE OVER MOST OF
THE AREA.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
THE THREAT OF LIGHT PCPN WILL RETURN TO THE FORECAST EARLY TUES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
PERHAPS A MORE SIGNIFICANT STORM SYSTEM WILL AFFECT THE REGION
SOMETIME LATE NEXT WEEK. SIMILAR TO YESTERDAY...OPERATIONAL MODEL
AND ENSEMBLE GUIDANCE STILL SHOW UNCERTAINTY WITH SHORTWAVE TIMING
AND POTENTIAL PHASING OF STREAMS. AFTER A TASTE OF WINTER THIS
WEEKEND...EXPECT TEMPERATURES TO SLOWLY MODERATE IN TIME
EVENTUALLY CLIMBING BACK NEAR TO SLIGHTLY ABOVE NORMAL BY THE END
OF THE MEDIUM RANGE PD.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
TYPICAL NW FLOW MEANS IFR/OCNL MVFR OVER THE WRN SITES OF BFD AND
JST. EXPECT VFR CIGS AT AOO. A BRIEF PD OF MVFR CIGS AND MVFR OR
EVEN IFR VSBY IS POSSIBLE BEFORE 00Z AT UNV AND IPT AS A WEAK SFC
TROUGH PUSHES ACROSS. THIS TROUGH COULD ALSO ENHANCE THE WINDS TO
20G30KT. VFR IN THE SERN SITES. THE GUSTY WINDS ELSEWHERE WILL
CONTINUE FOR THE EARLY EVENING WITH 40+ KT FLOW JUST 2-3KFT
ALOFT. THE GUSTS WILL DIMINISH SLIGHTLY THIS EVENING WITH SHALLOW-
ER MIXING AND THE HIGH BUILD TO OUR SOUTH. EXPECT THE WRN
TERMINALS TO STAY LOW IN VSBY AND CIGS THROUGH MOST OF THE NIGHT
AND FLURRIES COULD LAST INTO 12-15Z MONDAY. BIG SFC HIGH TO THE S
WILL MAKE FOR SUNNY SKIES OVER MOST OF THE AREA.
OUTLOOK...
TUE...MVFR IN -SN POSSIBLE.
WED...MAINLY VFR...WRN MTS MAY DIP TO MVFR IN SHSN.
THU...MVFR TO IFR IN SHRA/SN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ004-
005.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DEVOIR/CERU
LONG TERM...GRUMM/DEVOIR
AVIATION...DANGELO
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1006 AM CST SUN FEB 12 2012
.DISCUSSION...MADE A FEW CHANGES TO THE TEMPERATURE FORECAST BASED
ON CURRENT TRENDS AND LATEST MODEL DATA. OVERALL...NO SIGNIFICANT
CHANGES TO THE FORECAST. TEMPERATURES WILL NOT WARM MUCH THIS
AFTERNOON WITH OUR OVERNIGHT LOW TEMPERATURES BEFORE MIDNIGHT WITH
THE RETURN OF EAST TO SOUTHEAST WIND EXPECTED TO WARM TEMPERATURES
AFTER MIDNIGHT. PATCHY LIGHT RAIN ACROSS THE REGION THIS MORNING
SHOULD EXPAND IN COVERAGE THIS AFTERNOON THROUGH THE OVERNIGHT
HOURS AS THE MAIN/STRONGER UPPER LEVEL DISTURBANCE APPROACHES
SOUTH TEXAS. HAVE REMOVED THUNDER FOR THIS EVENING...YET KEPT IN
AFTER MIDNIGHT ACROSS THE EAST AS SOUNDING INDICATE THE HIGHER
LAPS RATES THAT WOULD SUPPORT EMBEDDED ELEVATED CONVECTION. NO
OTHER CHANGES AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 534 AM CST SUN FEB 12 2012/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...PASSING UPPER LEVEL DISTURBANCE WILL LEAD TO GRADUALLY
LOWERING CIGS THROUGH TODAY AND INTO TONIGHT. AS OF 12Z ALL AREAS
REMAIN VFR AS LOWER LAYERS OF THE ATMOSPHERE REMAIN DRY. THE
MOISTURE IN THIS LAYER WILL GRADUALLY INCREASE THROUGH THE MORNING
WITH CIGS LOWERING TO MVFR CONDITIONS. LATER IN THE AFTERNOON AND
EVENING PERIODS OF IFR CONDITIONS WILL BE POSSIBLE. WHILE RAIN IS
EXPECTED THROUGH THE DAY...A SLIGHT CHANCE OF THUNDERSTORMS WILL
DEVELOP THIS EVENING AND OVERNIGHT. EXPECT LITTLE TO NO
IMPROVEMENT IN CONDITIONS BY THE END OF THIS TAF PERIOD...BUT
CONDITIONS SHOULD IMPROVE QUICKLY MONDAY AFTERNOON.
PREV DISCUSSION... /ISSUED 437 AM CST SUN FEB 12 2012/
SHORT TERM (TODAY THROUGH MONDAY)...SEEING PATCHY LIGHT RAIN OR
DRIZZLE DEVELOP ACROSS SOUTHWEST CWA THIS MORNING ASSOCIATED WITH
THE FIRST PIECE OF ENERGY THAT WILL AFFECT THE AREA OVER THE NEXT
COUPLE OF DAYS. DPT DEPRESSIONS ARE STILL QUITE HIGH THIS
MORNING...10 TO 15 DEGREES FOR MOST LOCATIONS...SO WILL TAKE SOME
TIME TO REALLY GET ANY SUBSTANTIAL RAIN TODAY. RUC SOUNDINGS SHOW
LOW LEVELS BECOMING SATURATED BY MID TO LATE MORNING ACROSS THE
AREA. 300K SURFACE COND PRES DEFICITS LAG A BIT BEHIND THIS
TIMING...BUT 295K SURFACE IS A BIT QUICKER. WITH 25 TO 35KT
ISENTROPIC UPGLIDE THINK BY MID MORNING SOUTHWEST PORTION OF THE
CWA WILL BE SEEING LIGHT RAIN. WHILE TEMPERATURE PROFILE WILL BE
ABOVE ZERO IN THE LOWEST 200 MB...EVAPORATIVE COOLING WILL LIKELY
BRING THE PROFILE A LITTLE CLOSER TO ZERO FOR A TIME THIS MORNING.
HOWEVER THINK PRECIP SHOULD REMAIN IN THE LIQUID PHASE AT THE
SURFACE FOR ALL AREAS. RAIN CHANCES INCREASE THROUGHOUT THE DAY
AS UPGLIDE CONTINUES. PWAT VALUES REMAIN RELATIVELY LOW THROUGH
THE DAY...JUST ABOVE 1 INCH...WHICH SHOULD KEEP THE RAIN MAINLY
LIGHT. AN UPPER LEVEL JET STREAK MOVING INTO GOOD POSITION OVER
THE FORECAST AREA TONIGHT...AND SOME DECENT LOW TO MID LEVEL OMEGA
WILL BRING A SLIGHT CHANCE FOR THUNDER TONIGHT INTO MONDAY.
ISENTROPIC UPGLIDE CUTS OFF QUICKLY LATE MORNING AND EARLY
AFTERNOON ON MONDAY WITH MOISTURE ALSO QUICKLY DECREASING AS LAYER
WINDS SHIFT TO THE WEST. EXPECT MOST AREAS TO BE DONE WITH RAIN BY
AROUND NOON ON MONDAY. SOME RAIN COULD BE LINGERING FAR EAST.
SKIES SHOULD BEGIN TO CLEAR PRETTY QUICKLY IN THE AFTERNOON.
AS FOR TEMPERATURES...WILL SEE LITTLE INCREASE IN TEMPS THIS
AFTERNOON. WITH RUC MODEL ACTUALLY SHOWING HIGHS IN THE LOW TO MID
40S...BUT THINK THIS IS A BIT TOO LOW. MOST MODELS INDICATING HIGHS
IN THE LOWER TO MID 50S. FORECAST WILL REFLECT NEAR OR SLIGHTLY
UNDER A CONSENSUS OF GUIDANCE. WINDS SHIFT SOUTH AND SOUTHWEST FOR
MONDAY AND EXPECT TEMPS 15 TO 20 DEGREES HIGHER AREA WIDE.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...THE GFS/CANADIAN/ECMWF
PROG AN UPPER DISTURBANCE TO MOVE ACROSS THE SRN PLAINS/NRN TX
WEDNESDAY. RTN FLOW/INCREASING MSTR EXPECTED TUESDAY IN ADVANCE OF
THIS SYSTEM. THE GFS/ECWMF PROG A COLD FRONT...CORRESPONDING TO THE
UPPER DISTURBANCE...TO MOVE ACRS THE CWA WEDNESDAY AFTN/EVENING. THE
COMBINATION OF SFC AND UPPER FORCING WILL CONTRIBUTE TO CONVECTION
WEDNESDAY (GREATEST CHANCE OVER THE ERN CWA BASED ON MSTR
CONSIDERATIONS) WITH ACTIVITY ENDING AFTER FROPA. ANTICIPATE SCA
CONDITIONS OVER AT LEAST THE OFFSHORE COASTAL WATERS THURSDAY IN
RESPONSE TO THE FRONT. THE MODELS DIFFER WITH RESPECT TO THE UPPER
PATTERN THURSDAY-SATURDAY. REGARDLESS...ALL SOLNS APPEAR TO PROG AN
UPPER PATTERN CONSISTENT WITH ISENTROPIC LIFT. YET...THE GFS PROGS
ISENTROPIC LIFT SAT AND THE ECMWF SUNDAY. WILL ACCOUNT FOR
UNCERTAINTY BY FCSTG LOW POP PCPN FOR SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 55 55 73 54 74 / 60 90 50 0 10
VICTORIA 49 47 68 49 73 / 40 80 70 10 0
LAREDO 48 48 69 54 79 / 80 50 20 0 0
ALICE 52 52 71 52 76 / 60 90 40 0 0
ROCKPORT 54 54 70 57 68 / 50 90 60 10 10
COTULLA 45 45 67 49 77 / 50 60 20 0 0
KINGSVILLE 55 55 73 53 76 / 70 90 40 0 0
NAVY CORPUS 57 56 72 59 69 / 60 90 50 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT
20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS
FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
RG/82...UPDATE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1121 AM CST SUN FEB 12 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
206 AM CST SUN FEB 12 2012
MAIN FORECAST CONCERN IS ON LIGHT SNOW FOR MONDAY INTO MONDAY
NIGHT
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER SOUTHWEST INTO SOUTH CENTRAL CANADA...AS WELL AS
OVER TEXAS INTO COLORADO...A SHORTWAVE TROUGH OVER THE PACIFIC
NORTHWEST...A DEEPER SHORTWAVE TROUGH OVER THE DESERT SOUTHWEST...
AND A LONG-WAVE TROUGH ALONG THE EASTERN SEABOARD. WITH 500MB HEIGHTS
RISING OVER THE FORECAST AREA BEHIND THE LONG-WAVE TROUGH...WARMER
AIR ALOFT IS BEGINNING TO FLOW IN FROM CENTRAL CANADA. INTERESTING
THAT BETWEEN 00Z ON THE 10TH AND 00Z ON THE 12TH...850MB TEMPS HAVE
WARMED ABOUT 16C ACROSS MUCH OF CENTRAL CANADA PER 00Z RAOBS. IN
FACT...850MB TEMPS AT 00Z WERE -3C AT CHURCHILL MANITOBA...WARMER
THAN THE AVERAGE -13C OVER THE FORECAST AREA. AIRMASS REMAINS DRY
ACROSS THE ENTIRE UPPER MIDWEST...CENTRAL PLAINS AND UPPER
MISSISSIPPI RIVER VALLEY REGIONS...NOTED BY PRECIPITABLE WATER
VALUES BETWEEN 0.05-0.1 INCHES ON 00Z SOUNDINGS. THIS DRY AIR IS
ASSOCIATED WITH AN AREA OF HIGH PRESSURE AT THE SURFACE THAT
ENCOMPASSES ALL OF THE U.S. PLAINS. A SUSTAINED 5 TO 15 MPH
NORTHWEST WIND OVER THE FORECAST AREA...ON THE EAST SIDE OF HIGH...
HAS ONLY ALLOWED TEMPERATURES TO FALL INTO THE 8 TO 15F RANGE.
TODAY AND TONIGHT...THE UPPER RIDGING SEEN FROM TEXAS INTO COLORADO
IS PROGGED TO LIFT NORTHEAST TOWARDS THE AREA DURING THIS
PERIOD...IN RESPONSE TO THE TWO SHORTWAVE TROUGHS OUT WEST MOVING
OUT INTO THE WESTERN PLAINS. MOISTURE TRANSPORT OUT OF THE GULF OF
MEXICO AND DPVA AHEAD OF THESE TROUGHS SHOULD CAUSE PRECIPITATION TO
BREAK OUT ACROSS MUCH OF THE PLAINS TONIGHT...PERHAPS REACHING INTO
WESTERN IOWA LATE IN THE NIGHT. FOR OUR AREA...WE WILL REMAIN
INFLUENCED BY THE DRY AIR ASSOCIATED WITH THE SURFACE HIGH...AND ITS
RIDGE AXIS LOOKS TO CROSS TONIGHT. FULL SUN ANTICIPATED TODAY AND
WITH 850MB TEMPS PROGGED AROUND -6C AT 18Z...TEMPERATURES SHOULD
CLIMB INTO THE MID 20S TO NEAR 30. WILL STILL BE DEALING WITH A
NORTHWEST TO WESTERLY BREEZE...BUT IT DOES NOT LOOK AS BREEZY AS
YESTERDAY WITH A WEAKER PRESSURE GRADIENT PROGGED. THE WINDS MAY
HAVE A SHOT OF DECOUPLING TONIGHT...ESPECIALLY OVER WESTERN
WISCONSIN...SETTING UP BETTER RADIATIONAL COOLING. ON THE FLIP
SIDE...A WARMER DAY TODAY WILL PROBABLY END UP RESULTING IN LOWS
SIMILAR TO THOSE EXPERIENCED THIS MORNING. INCREASING MID/HIGH
CLOUDS LATER IN THE NIGHT WEST OF THE MISSISSIPPI RIVER SHOULD KEEP
TEMPERATURES A LITTLE WARMER THERE.
MONDAY AND MONDAY NIGHT...MODELS ARE IN GOOD AGREEMENT TAKING THE
TROUGHING OVER THE WESTERN PLAINS AT 12Z MONDAY MOSTLY INTO THE OHIO
VALLEY REGION MONDAY NIGHT. THERE IS A NORTHERN EXTENSION THAT
CROSSES THE FORECAST AREA LATE MONDAY INTO THE EARLY OVERNIGHT HOURS
MONDAY NIGHT. WITH THE BULK OF THE TROUGH HEADING MORE TO THE
SOUTH...THERE IS CONCERN ON HOW MUCH MOISTURE CAN MAKE IT NORTH INTO
THE FORECAST AREA. CERTAINLY MODELS SUGGEST IT HAPPENS ENOUGH TO
PRODUCE SOME LIGHT QPF ACROSS MUCH OF THE FORECAST AREA...THOUGH THE
BEST MOISTURE TRANSPORT AND ISENTROPIC LIFT STAYS TO THE SOUTH AND
EAST. SO BASICALLY THE HEIGHT FALLS AND DPVA FROM THE NORTHERN
EXTENSION OF THE TROUGH WILL BE THE MAIN FORCING FUNCTION FOR THE
PRECIPITATION. LOOKS LIKE PRECIPITATION SHOULD SLOWLY WORK SOUTHWEST
TO NORTHEAST ACROSS THE AREA ON MONDAY...WITH THE LINGERING DRY AIR
THE MAIN REASON FOR THE SLOW ADVANCEMENT. PRECIPITATION THEN
DIMINISHES WEST TO EAST AFTER MIDNIGHT MONDAY NIGHT AS THE TROUGH
PUSHES EAST. GOOD MODEL AGREEMENT REMAINS ON THIS LIGHT
PRECIPITATION EVENT...SO HAVING THE HIGH PRECIPITATION CHANCES AS
INDICATED BY THE PREVIOUS FORECAST SEEM REASONABLE. ONLY SLIGHT
UPWARD MODIFICATIONS WERE MADE. WITH RESPECT TO AMOUNTS...THINK THE
12.00Z NAM IS A LITTLE TOO HIGH ON QPF GIVEN WEAK FORCING OVERALL.
SHOULD MAINLY BE A 0.5 TO 1.5 INCH SNOW EVENT...WITH PERHAPS A
FEW TOTALS SLIGHTLY HIGHER THAN THAT. WITH A FLOW OF WARMER AIR
COMING IN WITH THE TROUGH...SLIGHTLY HIGHER HIGHS ARE ANTICIPATED
FOR MONDAY COMPARED TO TODAY. IN FACT...AREAS ACROSS WISCONSIN
COULD EVEN SEE SOME SUN IN THE MORNING. CLOUDY SKIES ARE EXPECTED
ACROSS THE AREA MONDAY NIGHT...AND WITH LITTLE OR NO COLD
ADVECTION...TEMPERATURES SHOULD ONLY DROP MAYBE 5 DEGREES FOR
LOWS.
TUESDAY AND TUESDAY NIGHT...IN THE WAKE OF THE MONDAY/MONDAY
TROUGH...MODELS SHOW ONE MORE SHORTWAVE MOVING WEST TO EAST ACROSS
THE FORECAST AREA LATE TUESDAY. APPEARS THIS SHORTWAVE WILL NOT HAVE
MUCH MOISTURE OR EVEN PRODUCE MUCH FORCING...THEREFORE HAVE DRY
CONDITIONS FOR TUESDAY. ON TUESDAY NIGHT...TROUGHING IS FORECAST TO
DROP DOWN INTO MANITOBA WHILE TROUGHING IS SHOWN AGAIN OVER THE
SOUTHWESTERN U.S.. HOWEVER...NEITHER FEATURE IS CLOSE ENOUGH TO
BRING ANY PRECIPITATION TO THE AREA. IN FACT...THERE SHOULD BE SOME
SLIGHT 500MB HEIGHT RISES TAKING PLACE. THEREFORE...DRY CONDITIONS
CONTINUE. 850MB TEMPS PROGGED AROUND -6C ON TUESDAY COMBINED WITH
SOME SLOW CLEARING AND A WARMER START WILL ALLOW FOR HIGHS A FEW
DEGREES WARMER THAN MONDAY. A LITTLE BETTER NIGHT INDICATED FOR
RADIATIONAL COOLING TUESDAY NIGHT WITH LIGHT WINDS...THOUGH THE
AIRMASS OVERALL IS RELATIVELY SPEAKING WARM WITH 850MB TEMPS HOLDING
NEARLY STEADY. IN ADDITION...THERE ARE HINTS OF SOME STRATUS TO MOVE
IN LATER IN THE NIGHT. FOR NOW...FOLLOWED A BLEND OF GUIDANCE FOR
LOWS.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT
206 AM CST SUN FEB 12 2012
12.00Z MODELS (ECMWF/CANADIAN/UKMET/GFS/GFS ENSEMBLES) DEPICT A
MESSY UPPER LEVEL FLOW PATTERN THROUGHOUT THE LONG TERM...RESULTING
IN QUITE A FEW DIFFERENCES BETWEEN ALL THE MODELS. IT APPEARS THIS
IS A RESULT OF A FAST...ZONAL FLOW ACROSS THE PACIFIC RUNNING INTO
SPLIT FLOW OVER THE U.S. AND SOUTHERN CANADA. DESPITE THE
DIFFERENCES OF HANDLING SHORTWAVES...IN GENERAL THE LONG TERM PERIOD
LOOKS PRETTY QUIET WITH ALL OF THE COLD...ARCTIC AIR BEING LOCKED UP
OVER VERY FAR NORTHERN CANADA. THERE ARE A FEW FEATURES THAT MODELS
AGREE UPON AND WILL DISCUSS THEM HERE. THE FIRST IS THE TROUGHING
THAT DEVELOPS OVER THE SOUTHWESTERN U.S. TUESDAY NIGHT. 12.00Z
ECMWF/GFS/UKMET ARE ALL IN AGREEMENT ON SHEARING THIS TROUGH OUT AND
TRACKING IT THROUGH THE OHIO VALLEY ON THURSDAY. THIS TRACK AND
GIVEN THE FACT THAT IS SHEARING WOULD KEEP THE BULK OF THE
PRECIPITATION SOUTH OF THE FORECAST AREA...OR PERHAPS CLIP NORTHEAST
IOWA AND FAR SOUTHWEST WISCONSIN. THE 12.00Z CANADIAN IS THE ONLY
MODEL NOW STILL SUGGESTING A FARTHER NORTH...MORE PHASED LOOK...
WHICH RESULTS IN A DEEPER SYSTEM SPREADING PRECIPITATION OVER MUCH
OF THE AREA WEDNESDAY NIGHT INTO THURSDAY. HAVE LOWERED
PRECIPITATION CHANCES SOME DURING THIS PERIOD GIVEN THE TREND TO THE
UN-PHASED LOOK...AND STILL WOULD NOT BE SURPRISED IF IT ENDS UP DRY
LIKE THE 12.00Z GFS SHOWS. UPPER LEVEL TROUGHING DOES DEVELOP OVER
THE UPPER MISSISSIPPI RIVER VALLEY REGION EASTWARD INTO NEW ENGLAND
FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT. 850MB TEMPS ARE ONLY AROUND
-4C IN THE TROUGH SO AGAIN...NOTHING THAT COLD. FLOW THEN TURNS MORE
ZONAL FOR SATURDAY OVER THE AREA WITH NO PRECIPITATION SEEN. SO
OUTSIDE OF THE WEDNESDAY NIGHT/THURSDAY TIME PERIOD...A DRY LONG
TERM FORECAST IS EXPECTED. NO BIG WARM-UPS PLANNED EITHER.
HOWEVER...GIVEN 850MB TEMPS STAYING MOSTLY BETWEEN -4C AND 1C...
SURFACE TEMPERATURES SHOULD AT LEAST END UP 5-10 DEGREES NORMAL FOR
BOTH HIGHS AND LOWS. LOOKING FARTHER OUT INTO EARLY NEXT
WEEK...STILL NO SUGGESTIONS OF ANY MAJOR COOL DOWNS AS THE FAST
PACIFIC FLOW CONTINUES...ALLOWING PACIFIC AIR TO CONTINUE TO FLOW
ACROSS THE U.S.
&&
.AVIATION...THROUGH 18Z MONDAY
1121 AM CST SUN FEB 12 2012
A RIDGE OF HIGH PRESSURE WILL DRIFT ACROSS THE AREA TONIGHT WITH
CLEAR SKIES EXPECTED THROUGH ABOUT 3 AM. WINDS WILL ALSO BE LIGHT
UNDER THE RIDGE...SLOWLY BACKING TO THE SOUTH THIS EVENING AND
REMAINING IN THE 5 TO 10KT RANGE AS THE RIDGE AXIS PUSHES EAST OF
THE AREA. HIGH/MID CLOUDS ARE THEN EXPECTED TO SPREAD WEST TO EAST
INTO THE AREA AFTER 3 AM AS A TROUGH OF LOW PRESSURE PUSHES INTO THE
PLAINS. LOOK FOR THE CLOUDS TO CONTINUE LOWERING...BUT REMAINING IN
VFR RANGE THROUGH MONDAY MORNING AS THE TROUGH PUSHES OUT OF THE
PLAINS TOWARD THE AREA. KRST COULD BE RIGHT ON THE CUSP OF
DETERIORATING INTO MVFR RANGE BY 17Z MONDAY...AND WILL LIKELY BECOME
MVFR/POSSIBLY IFR AT BOTH KRST/KLSE DURING THE AFTERNOON AS -SN
WORKS INTO THE AREA WITH THE APPROACHING TROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
206 AM CST SUN FEB 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS