Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/14/15
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
315 PM EST THU FEB 12 2015
.DISCUSSION...
TONIGHT/FRIDAY...
DRY/STABLE WX AS A DEEP W/NW FLOW PATTERN OVER THE GOMEX/DEEP SOUTH
PUSHES A DRY COLD FRONT THRU CENTRAL FL...AIDED BY A 120KT JET
STREAK LIFTING OFF THE MID ATLC COAST AND A 120KT JET DIGGING OUT OF
THE NRN PLAINS. RAP ANALYSIS CONTINUES TO SHOW LIMITED UPSTREAM
MOISTURE WITH MEAN RH VALUES BLO 50PCT THRU THE H100-H50 LYR. THE
12Z SOUNDINGS SHOW THE REGIONAL AIRMASS UNDER A SMOTHERING
SUBSIDENCE INVERSION IN THE H100-H85 LYR WITH PWAT VALUES AOB 0.50".
WHAT LITTLE MOISTURE THAT HAS MANAGED TO POOL WITHIN THE FRONTAL
TROF WILL NOT BE SUFFICIENT TO GENERATE ANYTHING MORE THAN A MID/UPR
LVL SCT DECK AT BEST.
WILL GO WITH CLR/MCLR SKIES OVERNIGHT. COLD AIR ADVECTION PATTERN
AS THE SFC PGRAD TIGHTENS BEHIND THE FRONT WILL PREVENT DECOUPLING
BUT WILL BE INSUFFICIENT TO GENERATE SFC WNDS HIGHER THAN 10MPH.
MIN TEMPS BOTTOMING OUT IN THE M/U30S W OF I-95 AND N OF I-4...
U30S/M40S ALONG THE COAST S OF I-4. WHILE NRLY SFC WINDS WILL
GENERATE WIND CHILLS IN THE L/M30S OVER MUCH OF THE CWA...L30S PSBL
ALONG N OF 1-4...SUSTAINED SPEEDS BLO 10MPH DOES NOT QUITE MEET
CRITERIA FOR A WIND CHILLS ADVISORY. COLD AIR ADVECTION PATTERN WILL
CONT INTO FRI. DESPITE MSUNNY SKIES...MAX TEMPS FRI WILL HOLD IN THE
L/M60S OVER MOST OF THE CWA...U60S PSBL VCNTY OF LAKE OKEECHOBEE.
SAT-WED...(EDITED FM PREV DISC)
TEMPERATURES WILL REMAIN BELOW NORMAL OVER THE WEEKEND AND INTO
EARLY NEXT WEEK. COOL HIGH PRESSURE TO START OUT SATURDAY WITH
ANOTHER REINFORCING SHOT OF COLD AIR ARRIVING VIA THE NEXT COLD
FRONT EARLY SUNDAY. A TEMPORARY UPTICK IN TEMPS TUE-WED AS FLOW
VEERS AROUND TO S-SW AHEAD OF NEXT FRONT.
12Z RUNS OF GFS AND ECMWF MOS GUIDANCE CONTINUE TREND INDICATING
SATURDAY WILL BE THE COLDEST MORNING WITH MANY LOCATIONS DROPPING
INTO THE MID TO UPPER 30S. THE TREASURE COAST AND BARRIER ISLAND OF
BREVARD SHOULD HOLD IN THE LOW TO MID 40S. NORMALLY COLDER RURAL
SPOTS NORTH AND WEST OF ORLANDO MAY BRIEFLY REACH FREEZING. DAYTIME
HIGHS THIS WEEKEND WILL BE QUITE COOL...MOSTLY IN THE 60S...BUT WITH
PLENTY OF SUNSHINE. AFTER A COLD START ON MONDAY...WINDS ARE
FORECAST TO TURN ONSHORE DURING THE DAYTIME AND BEGIN TO MODIFY THE
COLD DRY AIRMASS. A RAPID WARMUP IS EXPECTED BY TUE WITH HIGHS IN
THE MID 70S AS FLOW TURNS SOUTHERLY.
ANY ABOVE NORMAL TEMPS ON TUE LOOK TO BE SHORT LIVED AS BOTH GFS AND
ECMWF SHOW A DEEP UPPER TROUGH REDEVELOPING OVER THE PLAINS STATES
AND PUSHES EAST ACROSS FL LATE IN THE WEEK. THIS PATTERN WILL
SUPPORT ANOTHER COLD FRONTAL PASSAGE WEDNESDAY WITH ENOUGH UPPER
SUPPORT TO PRODUCE A CHANCE FOR RAIN. LOW POPS START LATE TUE NIGHT
ACROSS THE NORTH...THEN CHANCE/SCATTERED CATEGORY ALL AREAS DAYTIME
WED. HIGH PRESSURE BUILDING IN BEHIND THIS FRONT MAY PRODUCE ANOTHER
OUTBREAK OF MUCH BELOW NORMAL TEMPS LATE NEXT WEEK. MOS GUIDANCE IS
NOT INDICATING FREEZING TEMPS AT THIS TIME. BUT EVEN THOUGH THE DAYS
ARE GETTING LONGER...FREEZING TEMPS ARE POSSIBLE INTO LATE FEB
CLIMATOLOGICALLY. ONCE WE GET INTO THE MONTH OF MARCH...THE THREAT
FOR FREEZING TEMPS DECREASES MARKEDLY.
&&
.AVIATION...THRU 13/18Z
SFC WINDS: THRU 13/00Z...W 8-12KTS. BTWN 13/00Z-13/03Z...BCMG NW
7-11KTS...CONTG THRU 13/12Z.
VSBYS/WX/CIGS: BTWN 13/09Z-13/14Z LCL MVFR BR/STRATUS...OTHERWISE
VFR ALL SITES.
&&
.MARINE... TONIGHT-FRIDAY...HAZARDOUS BOATING CONDITIONS TO CONTINUE
ACRS THE LCL ATLC AS A DRY COLD FRONT SWEEPS THRU CENTRAL FL.
MODERATE TO FRESH N/NW BREEZE WILL BEGIN TO BEAT DOWN THE SWELL BY
FRI AFTN... BUT WITH SEAS HOLDING IN THE 6-8FT RANGE NEARSHORE AND
7-9FT RANGE OFFSHORE THRU DAYBREAK FRI...UP TO 10FT IN THE GULF
STREAM. DOMINANT PDS BTWN 13-14SEC. BOATING CONDITIONS WILL BE
HAZARDOUS NEAR INLETS DURING THE OUTGOING TIDES. WILL MAINTAIN THE
CURRENT SCA FOR SEAS THRU 03Z TONIGHT...SWITCHING TO A FULL SCA BTWN
03Z-15Z. WHILE CONDITIONS WILL IMPROVE SLOWLY AFT 18Z FRI...WILL
EXTEND GULF STREAM/OFFSHORE SCA THRU 03Z SAT AS THE OPPOSING NRLY
BREEZE/SRLY CURRENT WILL MAINTAIN ROUGH CONDITIONS PAST SUNSET.
SAT-MON...(FM PREV) PATTERN WILL SUPPORT PROLONGED NORTHERLY OR
OFFSHORE FLOW THROUGH THE WEEKEND WITH A COUPLE OF STRONG COLD
FRONTS BRINGING SURGES OF NORTH WINDS. ANOTHER COLD FRONT WILL BRING
A SECONDARY SURGE OF NORTH WINDS BY SUNDAY MORNING. WINDS FINALLY
TURN ONSHORE (NE-E) MONDAY AS HIGH PRESSURE PUSHES INTO THE ATLC.
BOATING CONDITIONS WILL REMAIN POOR TO HAZARDOUS ESPECIALLY IN THE
GULF STREAM.
&&
.FIRE WEATHER... LATEST MODEL TRENDS INDICATE VERY DRY AIR MASS INTO
CENTRAL FL THRU THE END OF THE WEEK. LEADING EDGE OF THE DRY AIR
WILL IMPACT CENTRAL FL FRI AFT... ANTICIPATE MIN RH VALUES BTWN 30-
35PCT FOR 4-6HRS OVER THE INTERIOR ALONG AND WEST OF THE FL TURNPIKE
AND N OF THE I-4 CORRIDOR. CRUX OF THE DRY AIR WILL PUSH IN SAT AFT
WITH MIN 30-35PCT MIN RH VALUES FOR 6-8HRS AREAWIDE WITH AREAS ALONG
AND N OF I-4 FALLING TO 25-30PCT FOR 4-6HRS. NW SFC WINDS NOT
EXPECTED TO EXCEED 12MPH...EVEN SO FIRE WX WATCHES AND/OR RED FLAG
WARNINGS MAY BECOME NECESSARY IF TREND HOLDS THROUGH LATER RUNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 43 57 35 61 / 0 0 0 0
MCO 43 62 39 63 / 0 0 0 0
MLB 47 62 40 62 / 0 0 0 0
VRB 47 64 42 64 / 0 0 0 0
LEE 40 59 37 62 / 0 0 0 0
SFB 43 59 37 63 / 0 0 0 0
ORL 44 61 41 63 / 0 0 0 0
FPR 47 64 42 65 / 0 0 0 0
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...HIGH SURF ADVISORY UNTIL 3 AM EST FRIDAY FOR COASTAL VOLUSIA
COUNTY-INDIAN RIVER-MARTIN-NORTHERN BREVARD COUNTY-SOUTHERN
BREVARD COUNTY-ST. LUCIE.
AM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST FRIDAY
FOR FLAGLER BEACH TO VOLUSIA-BREVARD COUNTY LINE 0-20 NM-
VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 0-20 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR FLAGLER BEACH TO VOLUSIA-BREVARD COUNTY LINE 0-
20 NM-FLAGLER BEACH TO VOLUSIA-BREVARD COUNTY LINE 20-60 NM-
SEBASTIAN INLET TO JUPITER INLET 0-20 NM-SEBASTIAN INLET TO
JUPITER INLET 20-60 NM-VOLUSIA-BREVARD COUNTY LINE TO
SEBASTIAN INLET 0-20 NM-VOLUSIA-BREVARD COUNTY LINE TO
SEBASTIAN INLET 20-60 NM.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST FRIDAY
FOR FLAGLER BEACH TO VOLUSIA-BREVARD COUNTY LINE 20-60 NM-
SEBASTIAN INLET TO JUPITER INLET 0-20 NM-SEBASTIAN INLET TO
JUPITER INLET 20-60 NM-VOLUSIA-BREVARD COUNTY LINE TO
SEBASTIAN INLET 20-60 NM.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...GLITTO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
956 PM CST FRI FEB 13 2015
.SHORT TERM...
328 PM CST
THROUGH SUNDAY...
HEADLINES: HAVE ISSUED A WINTER STORM WARNING FOR PORTER COUNTY
AND A WIND ADVISORY FOR LAKE COUNTY INDIANA...IN EFFECT STARTING
MID SATURDAY MORNING.
MAIN CONCERNS IN THE SHORT TERM:
*SCATTERED SNOW SHOWERS WITH ARCTIC FRONT LATE TONIGHT INTO
EARLY/MID SATURDAY MORNING.
ARCTIC FRONT TRAILING FROM LOW PRESSURE CURRENTLY OVER LAKE
SUPERIOR WILL SWEEP ACROSS THE AREA LATE TONIGHT. CORE OF -26 TO
-28C AIRMASS AT 850 MB WILL RUSH INTO THE AREA...RESULTING IN
QUICKLY STEEPENING LOW LEVEL LAPSE RATES. THIS AND NOSE OF 130+KT
UPPER JET ALONG WITH STRONG PVA FROM SHORTWAVE NOTED ON W/V
IMAGERY THIS AFTERNOON OVER WESTERN ONTARIO DIVING SOUTHWARD WILL
ENHANCE LIFT...RESULTING IN SCATTERED SNOW SHOWERS BREAKING OUT.
NOT ALL AREAS WILL SEE ANYTHING MORE THAN A DUSTING...BUT SOME
LOCATIONS ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80 COULD SEE
ROUGHLY BETWEEN A HALF INCH AND INCH OF ACCUMULATION.
CONFIDENCE IN MEDIUM-HIGH IN SNOW SHOWERS DEVELOPING AREA
WIDE...BUT HAVE MAINTAINED MID-HIGH CHANCE POPS AS EXPECTATION IS
FOR COVERAGE OF MEASURABLE SNOW TO BE SCATTERED IN NATURE.
*PLUMMETING TEMPERATURES AND VERY STRONG WINDS RESULTING IN
BITTERLY COLD WIND CHILLS LATE VALENTINES DAY INTO SATURDAY NIGHT
AND EARLY SUNDAY.
AFOREMENTIONED HIGHLY ANOMALOUS THERMAL TROUGH WILL SURGE INTO
AREA ON SATURDAY MORNING BEHIND ARCTIC FRONT. THUS HIGHS FOR THE
DAY WILL OCCUR EARLY...FOLLOWED BY QUICKLY FALLING TEMPERATURES
INTO THE SINGLE DIGITS AREA WIDE BY MID-LATE AFTERNOON. MAKING
MATTERS WORSE WILL BE RAPID NEARLY 6MB PER 3 HOUR PRESSURE RISES
LATE MORNING INTO THE EARLY AFTERNOON AS NEARLY 1050 MB ARCTIC
HIGH SPREADS SOUTH AND CLIPPER LOW DEEPENS TO SUB 1000 MB OVER
EASTERN LAKES. THIS WILL RESULT IN NORTH-NORTHWEST GUSTS TAPPING
MID TO EVEN HIGH 30S KT SPEEDS ALOFT...TRANSLATING INTO 35 TO 45
MPH WIND GUSTS AT THE SURFACE. ON THE INDIANA LAKEFRONT...WINDS
FROM FRICTIONLESS LAKE ARE LIKELY TO GUST TO 45 TO 50 MPH FROM THE
LATE MORNING THROUGH MID AFTERNOON. THUS HAVE ISSUED A WIND
ADVISORY FOR LAKE COUNTY FROM 15Z TO 00Z ON SATURDAY. THERE COULD
BE MINOR BLOWING SNOW/VSBY REDUCTION ISSUES FOR PORTIONS OF LAKE
COUNTY THAT OBSERVE FALLING SNOW THROUGH THE DAY. WILL TIE IN WIND
CONCERNS IN PORTER COUNTY INTO WINTER STORM WARNING.
WINDS WILL ONLY SLOWLY DIMINISH VALENTINES DAY EVENING AND
NIGHT...SO WIND CHILL VALUES WILL FALL TO 10 TO 20 BELOW BY EARLY
EVENING...AND THEN 15 TO 30 BELOW BY LATE SATURDAY NIGHT/EARLY
SUNDAY. WILL LIKELY NEED A WIND CHILL ADVISORY FOR MUCH OF
NORTHERN IL ALONG/NORTH OF I-80...BUT WOULD LIKE TO LET NEXT SHIFT
ASSESS POTENTIAL FOR WINDS TO DIMINISH A BIT SOONER AND RESULT IN
SLIGHTLY LESS COLD WIND CHILLS BY EARLY SUNDAY BEFORE DECIDING ON
WHAT COUNTIES TO INCLUDE IN THE ADVISORY. EXPECTING LOW
TEMPERATURES IN THE SINGLE DIGITS TO AROUND 10 BELOW ZERO AWAY
FROM LAKE EFFECT CLOUDS AND CHICAGO LAKEFRONT.
WILL ISSUE AN SPS FOR WIND/BITTER COLD/SNOW SHOWERS FOR COUNTIES
NOT YET IN HEADLINES.
*PERIODS OF MODERATE TO OCCASIONALLY HEAVY LAKE EFFECT SNOW IN
PORTER COUNTY ON SATURDAY...ALONG WITH BLOWING AND DRIFTING SNOW
AND SIGNIFICANTLY REDUCED VISIBILITY. THE LAKE EFFECT SNOW WILL
SHIFT WESTWARD LATE SATURDAY NIGHT INTO SUNDAY MORNING...BRINGING
MINOR ACCUMULATIONS TO AREAS NEAR LAKE IN NORTHEAST ILLINOIS
BEFORE ACTIVITY DIMINISHES SUNDAY AFTERNOON.
NOT MUCH HAS CHANGED REGARDING THE LAKE EFFECT SETUP SATURDAY INTO
SATURDAY NIGHT. FORECAST SOUNDINGS CONTINUE TO SHOW EXTREME LAKE
INDUCED INSTABILITY AND EQUILIBRIUM LEVELS NEAR OR OVER 10KFT...THOUGH
INVERSION HEIGHTS OF 5 TO 7KFT AS BEST CONVERGENCE MOVES INTO
PORTER COUNTY MAY PRECLUDE EXCESSIVE ACCUMULATIONS. AS BOUNDARY
LAYER FLOW SHIFTS FROM NNW TO NORTHERLY SATURDAY NIGHT...STRONG
CONVERGENCE AND HIGH INSTABILITY THROUGH DGZ COULD RESULT IN
MODERATE TO HEAVY RATES...AND LOCALIZED TOTAL ACCUMULATIONS OF
OVER 6 INCHES IN NORTHEASTERN PORTER COUNTY BY SUNDAY MORNING.
MESOLOW DEVELOPMENT AND BOUNDARY FLOW THEN BECOMING NORTHEAST THEN
EAST ON SUNDAY WILL TAKE LAKE BAND THROUGH LAKE COUNTY IN AND INTO
NORTHEAST IL BEFORE DIMINISHING. AT LEAST MINOR ACCUMULATIONS ARE
LIKELY FOR MUCH OF LAKE IN...COOK SHORE AND EVEN LAKE IL...BUT
CONFIDENCE IS LOW IN WHETHER A HEADLINE WILL BE NEEDED FOR ANY OF
THOSE COUNTIES.
DESPITE CONVERGENT AXIS REMAINING TO EAST OF PORTER ON SATURDAY
MORNING AND AFTERNOON...EXTREMELY COLD AIR MASS AND NNW FLOW WILL
LIKELY RESULT IN STEADY LIGHTER TO OCCASIONALLY MODERATE SNOW
SHOWERS INTO PORTER AND POSSIBLY EVEN EASTERN LAKE COUNTY INDIANA.
COMBINATION OF: STRONG WINDS...NEW SNOW FROM THURSDAY AND FALLING
SNOW THROUGH THE DAY ON SATURDAY BLOWING AND DRIFTING AND REDUCING
VISIBILITY...IS WHY I OPTED TO START THE WSW FOR PORTER COUNTY
SATURDAY MORNING.
RC
&&
.LONG TERM...
348 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
BELOW TO MUCH BELOW NORMAL TEMPERATURES...AND GENERALLY DRY
CONDITIONS THAT HAVE BEEN TYPICAL MUCH OF JANUARY AND FEBRUARY
WITH THE EXCEPTION OF THE SUPERBOWL SNOWSTORM LOOK TO BE IN PLACE
NEXT WORK WEEK. THIS WILL BE DUE TO CONTINUED HIGH AMPLITUDE
RIDGING FROM THE NORTHEASTERN PACIFIC INTO WESTERN NORTH
AMERICA...WITH TROUGHING OVER THE EASTERN HALF OF THE CONUS
KEEPING US IN DRY NORTH-NORTHWEST FLOW ALOFT. THE NEXT SHOT OF
BITTERLY COLD ARCTIC AIR WILL ARRIVE BY WEDNESDAY BEHIND A CLIPPER
SYSTEM THAT COULD BRING SOME LIGHT SNOW LATER MONDAY INTO EARLY
TUESDAY. THE LAKE EFFECT MACHINE WILL LIKELY FIRE UP AGAIN ON LAKE
MICHIGAN...BUT FROM THIS VANTAGE POINT...BOUNDARY LAYER FLOW COULD
KEEP THE BRUNT OF THE ACTIVITY EAST OF OUR NORTHWEST INDIANA
ACTIVITIES IN THE MID TO LATE WEEK PERIOD.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* CIGS GRADUALLY LOWERING TO MVFR THROUGH LATE EVENING.
* SCATTERED SNOW SHOWERS DEVELOPING TOWARD MORNING.
* STRONG GUSTY NORTH-NORTHWEST WINDS THROUGH THE DAY SATURDAY.
RATZER
//DISCUSSION...UPDATED 00Z...
WEAK MID-LEVEL DISTURBANCE WHICH BROUGHT A FEW FLURRIES TO PARTS
OF THE AREA EARLIER TODAY IS TRACKING OFF TO THE EAST OF THE AREA
EARLY THIS EVENING. A MUCH STRONGER UPPER WAVE WILL DIG SOUTHEAST
INTO THE REGION OVERNIGHT HOWEVER...WITH A DEEPENING SURFACE LOW
MOVING ACROSS THE NORTHERN GREAT LAKES TRAILING A STRONG ARCTIC
COLD FRONT ACROSS THE TERMINALS. WINDS WILL SHIFT TO THE WEST-
NORTHWEST BEHIND THE SURFACE FRONT LATE TONIGHT...TURNING MORE
NORTHWEST AND BECOMING STRONG AND VERY GUSTY SATURDAY MORNING AS
COLD ARCTIC AIR SPREADS IN AHEAD OF STRONG CANADIAN HIGH PRESSURE.
SCATTERED SNOW SHOWERS ARE EXPECTED BEHIND THE FRONT SATURDAY
MORNING IN THE INITIAL STRONG COOLING AND STEEP LOW LEVEL LAPSE
RATE ENVIRONMENT...WITH THE FOCUS FOR ANY LINGERING SNOW SHOWERS
SHIFTING OFF TO THE EAST/SOUTHEAST BY AFTERNOON. MVFR CIGS DURING
THE MORNING HOURS WILL LIKELY RAISE/SCATTER TO VFR BY LATE
AFTERNOON AS DRY/COLD AIR CONTINUES TO POUR IN FROM THE NORTH.
SPEAKING OF THE NORTH WINDS...GUIDANCE DEPICTS DIRECTION VEERING
TO 330-340 DEGREES WITH GUSTS ABOVE 30 KT SATURDAY MORNING AND
EARLY AFTERNOON...GRADUALLY DECREASING SATURDAY EVENING.
IN THE VERY NEAR TERM...VFR CIGS 3500-4000 FT EXPECTED TO
GRADUALLY LOWER TO 2000-2500 FT BY LATE THIS EVENING AS COLD FRONT
APPROACHES. COULD BE SOME SCATTERING A FEW HOURS AFTER MIDNIGHT
FOR A SHORT PERIOD BEFORE CLOUDS FILL BACK IN WITH STRONG DIGGING
DISTURBANCE ALOFT.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH IN CIGS LOWERING TO MVFR BY MIDNIGHT.
* MEDIUM-HIGH IN SHSN DEVELOPING BY SATURDAY MORNING... MEDIUM-LOW
WITH IMPACTS TO VSBY.
* MEDIUM-HIGH IN WIND TRENDS THROUGH SATURDAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...LAKE EFFECT SNOW SHOWERS LIKELY WITH POTENTIAL IFR.
NORTHEAST WINDS.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO NORTHWEST
WINDS.
RATZER
&&
.MARINE...
221 PM CST
FOR HEADLINES...THE FREEZING SPRAY AND GALE WARNING STILL LOOK VERY
ACCURATE IN TIMING. GUIDANCE DOES NOT SUPPORT SUSTAINED STORM FORCE
GUSTS SO WILL CONTINUE TO HAVE OCNL STORM FORCE GUSTS IN THE
GLF...NO STORM FORCE HEADLINE IS EXPECTED AT THIS TIME.
HIGH PRESSURE HAS SHIFTED SE AND A WEAK LOW IS OVER SOUTH CENTRAL
ONTARIO. WINDS HAVE GRADUALLY INCREASED TO 30 KT OVER THE LAKE AND
EXPECTING THEM TO INCREASE FURTHER AS THE LOW SHIFTS OVER THE
EASTERN LAKES. THE PRESSURE GRADIENT WILL INCREASE OVERHEAD LEADING
TO GALES ACROSS THE LAKE BY EARLY SATURDAY MORNING. COULD SEE OCNL
STORM FORCE GUSTS TO 50 KT OVER THE LAKE LATE SATURDAY MORNING AND
EARLY IN THE AFTERNOON...BUT SUSTAINED STORM FORCE WINDS ARE NOT
EXPECTED AT THIS TIME. NORTH WINDS DIMINISH SATURDAY EVENING AS THE
GRADIENT WEAKENS AND THE HIGH SPREADS OVERHEAD. WINDS BECOME
NORTHEAST TO EAST SUNDAY EVENING AND CONTINUE TO VEER TO SOUTH OR
SOUTHEAST BY MONDAY MORNING. A COLD FRONT SWINGS OVER THE LAKE LATE
MONDAY NIGHT INTO EARLY TUESDAY MORNING WITH WINDS BECOMING WEST AND
THEN NORTHWEST BEHIND THE FRONT. NORTHWEST WINDS INCREASE TO 30 KT
TUESDAY NIGHT AND THEN WEAKEN AND BACK TO WEST AS A HIGH PRESSURE
SYSTEM PASSES SOUTHWEST OF LAKE THURSDAY. THE PATTERN LOOKS BUSY
GOING INTO LATE NEXT WEEK WITH ANOTHER LOW PRESSURE SYSTEM IMPACTING
THE LAKE NEXT WEEKEND.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...WINTER STORM WARNING...INZ002...9 AM SATURDAY TO 9 AM SUNDAY.
WIND ADVISORY...INZ001...9 AM SATURDAY TO 6 PM SATURDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 3 AM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY
TO 3 AM SUNDAY.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
836 PM CST Fri Feb 13 2015
.UPDATE...
ISSUED AT 825 PM CST FRI FEB 13 2015
Latest surface analysis indicating the next Arctic cold front was
located over central Wisconsin southwest through north central
Iowa and is expected to sweep through our area between 6 and 9 AM
Saturday morning accompanied by scattered snow showers and a strong
northwest wind, gusting as high as 40 mph at times. Already starting
to see strong 3 hourly pressure rises across North Dakota indicating
the front should accelerate southeastward tonight with the latest
short term models continuing to suggest the boundary will be south
of most of our area by early afternoon.
Weak shortwave noted on the water vapor loop over western North
Dakota has a small area of light snow associated with it as it
tracks southeast. HRRR and Rapid Refresh models indicate the better
threat for snow showers with this weak wave would be over west
central thru southeast IL tomorrow morning. HRRR indicating around
0.05 inches of QPF associated with this band of light snow which
would be just under an inch of snow. However, this situation is
very similar to a couple of days ago in which we saw some very
narrow but intense bands of snow showers just behind the Artic
boundary, which lasted less than an hour in most locations with
most areas seeing less than a half inch. The main concern with
this particular front will be with the strong pressure rises
immediately behind the boundary tomorrow morning suggesting about
a 2 to 4 hour period of strong winds with gusts around 40 mph out
of the northwest tomorrow morning into the mid afternoon hours.
Whatever we see with respect to light snow should be well south of
our area by mid afternoon as the Arctic air mass settles across
the Midwest for the remainder of the weekend.
Have made some minor tweaks to the early evening temperatures
and POPs, especially across west central IL just before dawn
Saturday. The rest of the forecast is right on track this evening.
Updated ZFP out by 900 PM.
&&
.SHORT TERM...(Tonight)
ISSUED AT 257 PM CST FRI FEB 13 2015
Arctic cold front currently across the Upper Midwest will drop
southward into north-central Illinois tonight, reaching the I-74
corridor by dawn Saturday. Models continue to depict a band of
snow-showers accompanying the front as it quickly passes late
tonight into Saturday morning. 18z NAM time-height cross-sections
show strong lift within the 850-700mb layer along/ahead of the
boundary, but do not indicate full saturation within the profile.
Despite lack of deep moisture, think low-level convergence/lift will
be sufficient to trigger scattered snow-showers across the northern
KILX CWA late tonight. Have therefore included chance PoPs
along/north of I-74 after 3am. Further south, dry conditions will
prevail through the night. Winds will initially be W/SW this
evening, but will veer to the N/NW and increase markedly once the
front passes. Will likely see wind gusts in the 30-35mph range
across the far north by dawn. Overnight low temperatures will
mainly be in the lower to middle 20s, but will drop into the teens
north of a Canton to Bloomington-Normal line.
&&
.LONG TERM...(Saturday through Friday)
ISSUED AT 257 PM CST FRI FEB 13 2015
A vigorous clipper system, currently diving across the Canadian
Prairies, will impact central and southeast Illinois on Saturday.
While the center of the surface low and better moisture will pass
well north/east of the forecast area, the gusty winds associated
with the system and cold temperatures in its wake will be featured
prominently across the area. The trailing cold front will dive
across the area early Saturday, with temperatures falling through
most of the day. There will be minimal moisture for the front to
work with as it dives through the area, but it should still be able
to squeeze out a few snow showers or flurries as forecast soundings
suggest ice crystals will be present. Still looking like a a Wind
Chill Advisory will be needed later Saturday night into Sunday
morning across the far northern portion of the forecast area,
especially along/north of the I-74 corridor. Even in areas where
advisory criteria will not be specifically met, it will be bitterly
cold Saturday night into Sunday.
Another wave will dive toward the area by late Sunday into early
Monday, but this one is progged to come ashore along the Pacific
Northwest. As such, the best forcing/snow chances with this system
should stay just to our south. That being said, at least the
southern fringe of the forecast area is in line to be impacted by
some jet/frontogenetical forcing associated with this wave. Still
expect most of the forecast area to be missed by this wave, but snow
accumulations as high an inch or two could be seen south of I-70.
The additional energy that follows the lead Pacific wave is now
expected to stay well south of the forecast area Monday/Tuesday as
the North American trof broadens to encompass much more of the
continent. No additional disturbances of consequence are currently
expected for the remainder of the forecast period. Temperatures will
remain below to well below normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 545 PM CST FRI FEB 13 2015
Another fast moving Arctic front is expected to push across our
area tomorrow morning (12z-15z) switching our winds into the
northwest with a few gusts around 35 kts at times into the
afternoon hours and accompanied by scattered snow showers and
possibly some brief MVFR cigs. Front was located well north of
our area early this evening but will track quickly southeast into
central Illinois Saturday morning. We expect mainly sct-bkn VFR
clouds before the front gets here with soundings indicating an
increase in low level moisture along the Arctic boundary Saturday
morning. Winds ahead of the front will be out of the south to
southwest tonight at around 10 kts before veering more into a
westerly direction late tonight just ahead of the cold front.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Smith
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
325 AM CST THU FEB 12 2015
.SHORT TERM...
254 AM CST
THROUGH FRIDAY...
MAIN FOCUS FOR TODAY WILL BE ON THE DEVELOPING LES BAND/S...AND
POSITIONING. LOBE OF VORTICITY WAS PIVOTING EAST ACROSS NORTHERN IL
EARLY THIS MORNING...WITH SOME MOISTURE BEING SQUEEZED OUT AND
PRODUCING FLURRIES/LGT SNOW. WITH THE PROGRESSIVE FLOW...THIS
FEATURE SHOULD HAVE PUSHED EAST OF THE FORECAST AREA SHORTLY AFT
DAYBREAK. IN ADDITION EXPECT JUST SOME LINGERING FLURRIES...BUT SHUD
END SHORTLY AFTER DAYBREAK. RADAR IMAGERY OVER LAKE MICHIGAN
INDICATES A LITTLE ORGANIZATION TRYING TO FORM ALONG THE EASTERN
SHORE...HOWEVER IT COULD STILL TAKE A FEW HOURS UNTIL THE BETTER
BAND DEVELOPS. WITH THE SHORTWAVE PIVOTING EAST ACROSS THE
REGION...WINDS ARE QUICKLY TURNING TO A 330-350 DEG DIRECTION. THIS
WILL TAP INTO THE LONGER FETCH FOR LES DEVELOPMENT...WHICH IS
SUPPORTED BY THE HI-RES GUIDANCE.
WEAK CONVERGENCE WILL DEVELOP ALONG THE EASTERN SHORE OF LAKE
MICHIGAN ARND DAYBREAK...WITH A WEAK MESO-LOW TRYING TO FORM BASED
ON THE LOCAL ARW SOLUTION. LAPSE RATES REMAIN STEEP THROUGH EARLY
THIS EVE...WITH THE MESO-LOW PROGGED TO BLEED WEST/SOUTHWEST ACROSS
THE SOUTHERN TIP OF THE LAKE. THIS WOULD POSSIBLY BRING THE LES BAND
WEST TOWARDS LAKE COUNTY INDIANA...BUT FOR THE MOST PART IT STILL
APPEARS THE BULK OF THE SNOW BAND WILL IMPACT A PORTION OF NORTHEAST
PORTER COUNTY TO SOUTHWEST LWR MI. THE GRADIENT TIGHTENS UP THIS
MORNING...AND WILL ALLOW NORTH TO SLIGHTLY NORTHWEST WINDS TO GUST
BETWEEN 30-40MPH. THE GRADIENT IS JUST A TOUCH STRONGER OVER THE
LAKE...WHICH COULD ALLOW SOME HIGHER GUSTS TO 45 MPH ACROSS
LAKE/PORTER COUNTIES. NO PLANS TO CHANGE THE CURRENT HEADLINE...WITH
TOTAL SNOWFALL BETWEEN 3 AND 6 INCHES IN FAR NORTHEAST PORTER
COUNTY...HOWEVER IF THE CONVERGENCE AND MESO-LOW CAN DRIFT WEST
EARLIER...THIS WOULD BRING HIGHER TOTALS WEST INTO NORTHEAST LAKE
COUNTY.
SFC TEMPS HAVE BEEN SLOWED IN COOLING DUE TO THE CLOUD
COVER...HOWEVER THIS WILL BE TEMPORARY AS THE POTENT 850MB THERMAL
TROUGH OF -18 TO -22 DEG C AIR ARRIVES BY DAYBREAK. WITH STRONG COLD
AIR ADVECTION TODAY...TEMPS WILL LIKELY NOT MOVE MUCH FROM THE
SINGLE DIGITS ABOVE ZERO. THE FAR SOUTHERN PORTIONS OF THE FORECAST
AREA COULD SEE TEMPS HOVER IN THE LOW TEENS...BUT WILL LIKELY FALL
INTO THE SINGLE DIGITS BY THIS AFTERNOON.
THIS EVENING THE MESO-LOW IS PROGGED TO WEAKEN AS WINDS BACK
NORTHWESTERLY AND EVENTUALLY WEST LATE TONIGHT. HIGH PRESSURE WILL
BE SLIDING SOUTHEAST ACROSS CENTRAL IL. THIS WILL ALLOW THE LES BAND
TO MOVE BACK EAST OF PORTER COUNTY LATE THIS EVENING. WITH MINIMAL
CLOUD COVER TONIGHT...EXPECT TEMPS TO QUICKLY COOL. DESPITE WINDS
SLOWLY DIMINISHING...WINDS CHILLS TONIGHT WILL DIP INTO THE SINGLE
DIGITS BELOW ZERO.
DRY AIR WILL LINGER INTO MUCH OF FRI...AS THE SFC RIDGE SLIDES EAST.
WARM AIR WILL TRY TO QUICKLY ADVECT NORTHEAST...ALLOWING TEMPS TO
REBOUND INTO THE LOW/MID 20S. ENSEMBLES CONTINUE TO DOWNPLAY THE
PRECIP FOR FRI...WITH ONLY A FEW MEMBERS INDICATING ANY PRECIP NOW.
EXPECT GIVEN THE EXPANSIVE DRY WEDGE...THAT WHILE SOME ISENTROPIC
ASCENT WILL OCCUR...THAT ANY PRECIP WILL LIKELY BE NORTH IN WISC.
HAVE TRENDED DRIER...WITH ONLY A SLT CHC POPS FRI MORNING. A
SHORTWAVE WILL BE SLIDING EAST ACROSS LAKE HURON FRI NGT...WITH A
TRAILING BOUNDARY STRETCHING WEST ACROSS WISC. MOISTURE IS BEING
PROGGED ALONG THE BOUNDARY AS IT SLIDES SOUTH ACROSS THE FORECAST
AREA LATE FRI NGT/SAT MORNING...WHICH COULD PRODUCE SOME FLURRIES OR
LGT SNOW.
BEACHLER
&&
.LONG TERM...
254 AM CST
SATURDAY THROUGH WEDNESDAY...
ANOTHER PUNCH OF ARCTIC AIR ARRIVES SAT WITH A POTENT SFC RIDGE
DIVING SOUTH FROM CENTRAL CANADA. ENSEMBLES CONTINUE TO DEMONSTRATE
A HIGH CONFIDENCE IN THE 850MB THERMAL TROUGH OF -24 TO -26 DEG C
ARRIVING SAT/SUN...MAKING IT TOUGH FOR TEMPS SAT/SUN TO WARM BEYOND
THE SINGLE DIGITS ABOVE ZERO. THEN AS THE SFC RIDGE ERODES THE CLOUD
COVER SAT NGT...TEMPS WILL RADIATE TO -5 TO -12 DEG. WINDS WILL
LIKELY REMAIN BLUSTERY...POSSIBLY CREATING DANGEROUS WIND CHILL
CONDITIONS OF -20 TO -30 DEG INTO EARLY SUN. LES LOOKS ONCE AGAIN
FAVORABLE FOR PORTIONS OF NORTHWEST IN SAT NGT/SUN.
ENSEMBLES SUGGEST THE THERMAL TROUGH WILL RELAX MON/TUE...ALLOWING
SFC TEMPS TO WARM BACK TO THE 20S. THE LONGWAVE PATTERN BEGINS TO
AMPLIFY MON...WITH THE STRENGTHENING RIDGING APPROACHING EASTERN
ALASKA. ADDITIONALLY ENSEMBLES ARE SUGGESTING SOME DEGREE OF
BLOCKING ACROSS THE NORTH ATLANTIC...WHICH LIKELY WILL AID IN THE
DIGGING TROUGH ACROSS THE CONUS BY TUE. THIS SOLUTION WOULD LIKELY
POINT TOWARDS A RETURN TO SUB-SEASONAL TEMPERATURES. WITH A DIGGING
TROUGH ACROSS THE CENTRAL CONUS...THE LIKELIHOOD OF AN ACTIVE
PATTERN FOR TUE/WED LOOKS GOOD.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LIGHT SNOW/IFR VIS THRU 12Z.
* STRONG/GUSTY NORTHWEST WINDS THRU THIS AFTERNOON. CMS
//DISCUSSION...UPDATED 09Z...
LIGHT SNOW HAS BECOME PREVAILING OVER THE ENTIRE AREA EARLY THIS
MORNING WITH VISIBILITIES DROPPING TO AROUND 2SM...OCCASIONALLY
LOWER. BACK EDGE OF THIS LIGHT SNOW IS CROSSING THE IL/WI STATE
LINE AND SHOULD GRADUALLY MOVE SOUTH OF THE TERMINALS IN THE 11Z
TO 13Z TIME PERIOD. SOME ENHANCEMENT OVER THE FAR SOUTHERN END OF
THE LAKE WILL MOVE INTO NORTHWEST INDIANA AND GYY WITH VIS TO 1SM
OR PERHAPS BRIEFLY LOWER. CMS
PREVIOUS 06Z DISCUSSION...
A SECONDARY COLD FRONT/TROUGH WILL BE MOVING SOUTH ACROSS THE
TERMINALS OVERNIGHT AND WITH IT THE POTENTIAL FOR SNOW SHOWERS
THAT MAY DROP VISIBILITIES TO IFR. THE STRONGEST OF THESE SNOW
SHOWERS CURRENTLY ARE MOVING ACROSS SOUTHWEST WI AND NORTHEAST IA.
HOW FAR EAST THESE EXTEND...INCLUDING INTO THE CHICAGO AREA TAFS
IS A BIT UNCERTAIN BUT MAINTAINED TEMPO WITH TWEAKED TIMING. MID
CLOUDS CURRENTLY PUSHING ACROSS THE AREA WILL LOWER TO 3-5KFT WITH
MVFR CIGS WITH ANY SNOW SHOWERS. CIGS LIKELY TO REMAIN VFR INTO
THURSDAY MORNING...THOUGH SOME MVFR IS POSSIBLE.
LAKE EFFECT SNOW WILL CONTINUE TO DEVELOP OVERNIGHT AND SLOWLY
MOVE WEST INTO NORTHWEST INDIANA THURSDAY MORNING. MAINTAINED
MENTION AT GYY...BUT ITS POSSIBLE THE LAKE EFFECT SNOW WILL REMAIN
JUST EAST OF GYY. AT THIS POINT...TOO CLOSE TO CALL FOR GYY. THIS
LAKE EFFECT SNOW IS NOT EXPECTED TO MOVE ANY FURTHER WEST THAN
GYY.
NORTHWEST WINDS HAVE DIMINISHED SOME THIS EVENING WITH SOME AREAS
NOT SHOWING GUSTS. EXPECT WINDS TO SLOWLY INCREASE AS LOWER CLOUDS
AND COLDER AIR ARRIVE. STILL APPEARS THE STRONG SPEEDS/GUSTS WILL
OCCUR FROM JUST BEFORE DAYBREAK THROUGH LATE MORNING...THEN SPEEDS
WILL SLOWLY BUT STEADILY DIMINISH THURSDAY AFTERNOON...BECOMING
LIGHT WESTERLY THURSDAY EVENING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH FOR LIGHT SNOW/IFR VIS THRU 12Z.
* MEDIUM FOR WINDS THRU THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...PERIOD OF -SHSN WITH IFR VSBY PROBABLE.
SATURDAY...CHANCE OF FLURRIES AND MVFR CIGS. STRONG NW WINDS.
SUNDAY...VFR PROBABLE.
MONDAY...VFR DURING DAY...SNOW AND IFR AT NIGHT.
TUESDAY...MVFR CIGS POSSIBLE.
IZZI
&&
.MARINE...
325 AM...HIGH PRESSURE BUILDING ACROSS THE NORTHERN PLAINS AND
UPPER MIDWEST WILL SLOWLY WEAKEN AS IT REACHES THE SOUTHERN LAKES
AND OHIO VALLEY FRIDAY MORNING. NORTHERLY GALES WILL GRADUALLY
DIMINISH FROM NORTH TO SOUTH THIS AFTERNOON. AS THE HIGH PASSES
ACROSS THE LAKE...SPEEDS WILL DROP INTO THE 10KT RANGE THEN TURN
SOUTHWESTERLY BY FRIDAY MORNING AHEAD OF THE NEXT LOW WHICH WILL
MOVE SOUTHEAST ACROSS ONTARIO FRIDAY. THE GRADIENT WILL STEADILY
TIGHTEN...WITH WINDS INCREASING TO 25-30KT FRIDAY AFTERNOON. WINDS
WILL SHIFT NORTHWEST BEHIND A TRAILING COLD FRONT FRIDAY NIGHT...
THEN INCREASE TO GALE FORCE BY SATURDAY MORNING AS ANOTHER STRONG
ARCTIC HIGH BUILDS SOUTH ACROSS THE NORTHERN PLAINS AND UPPER
MIDWEST SATURDAY AFTERNOON INTO SATURDAY NIGHT. THIS HIGH WILL
PASS OVER THE LAKE SUNDAY WITH DIMINISHING WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...WINTER WEATHER ADVISORY...INZ002 UNTIL 6 PM THURSDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 3 PM THURSDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM
THURSDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
258 AM CST Thu Feb 12 2015
.SHORT TERM...(Today)
ISSUED AT 257 AM CST THU FEB 12 2015
A surface wave is currently moving through the area with cloudy
skies, gusty winds up to around 35 mph, and a brief period of light
snow/flurries. By 12Z, the light snow will have ended over most of
the area, but winds will still be gusty and clouds could still be
around. Eastern and southeastern areas of the CWA might still some
flurries, but with issuance of the new forecast, will not have any
light snow/flurries mentioned. Skies should become partly to mostly
sunny during the morning hours as well. Cold Arctic high pressure
will build in behind this wave and this will keep temps around 15
degrees below normal across the whole area. With sun angle getting
higher, and should be lots of sun this afternoon, and winds should
be on the decrease; will follow closer to the warmer guidance, the
MAV.
&&
.LONG TERM...(Tonight through Wednesday)
ISSUED AT 257 AM CST THU FEB 12 2015
Shortwave currently rounding the top of the ridge west of the
Rockies will be racing southeast, arriving in our area Friday
morning. Not a lot of moisture available until the morning hours,
and the forecast soundings show a sizable dry column below 750 mb.
NAM and Canadian models are most bullish with squeezing out a
hundredth or two as far south as southern Illinois in the warm air
advection pattern, while the GFS and ECMWF quickly shift any
measurable precip across Iowa/northern Missouri to the northeast.
Largely went with a chance of flurries across the northern CWA with
this feature, with some 20% PoP`s in the far north. Should see some
temperatures above freezing west of Springfield, the best shot of
seeing above-freezing temperatures for the next week.
Well-advertised Arctic surge will quickly overspread the Midwest
late Friday night and Saturday, as a strong closed upper low drops
southeast. The latest models have nudged this low a bit further
east. As a result, the NAM and GFS are indicating more of a glancing
blow from this surge, while the ECMWF and Canadian models remain a
little more in the coldest air. Not much change in thinking for
Saturday`s temperatures though, as highs will occur early and
temperatures will steadily fall after that. Will likely see some
wind gusts to around 35 mph on Saturday with the surge, and winds
stay up enough overnight to continue suggesting advisory-level wind
chills north of I-72 Saturday night, when actual lows will be a few
degrees either side of zero.
Forecast for early next week remains challenging. Broadening upper
trough will be digging down the spine of the Rockies Monday night,
before shifting eastward through mid week. The GFS and ECMWF models
are showing some discrepancies in the development of a surface
cyclone just ahead of this, as a piece of energy ejects from an
upper low over the Baja which will be shearing out. The ECMWF has
not changed too much from the morning run, largely keeping our area
dry until Tuesday morning when the incoming trough boots the system
northeast. The GFS is a little faster and further north, with
overrunning precipitation by Monday afternoon and periodic snow over
the southeast half of the forecast area until late Tuesday evening,
when the deformation zone on the back side moves east of the area.
Have made some refinements in the PoP`s as a result, limiting the
likely PoP`s to areas south of I-70. Another Arctic surge follows
mid week, although the ECMWF is slower by about 12-18 hours than the
GFS solution.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1105 PM CST WED FEB 11 2015
An Arctic cold front will sweep across the area early this morning
accompanied by gusty northwest winds, scattered flurries and cigs
deteriorating to MVFR once again. Leading edge of the clouds pushing
across west central IL with another band over northeast Iowa into
south central Wisconsin. Latest guidance suggests a rapid push to
the southeast with both cloud bands as the colder air rushes in
during the early morning hours. RAP and HRRR forecast soundings
indicate the clouds should begin to push southeast out of our
area in the 16z-20z time frame as large scale subsidence/sinking
air settles in across the area in the wake of the strong upper
wave tracking to our north. We should see VFR conditions during
the afternoon although the gusty northwest winds are expected to
continue with a quick diminishing trend setting in late in the
afternoon as the center of the cold air mass settles in from the
northwest.
Look for northwest winds of 15 to 20 kts overnight with a few
gusts around 30 kts at times. Northwest to north winds are
expected across the TAF sites on Thursday with speeds of 13 to 18
kts with gusts in the 25-30 kt range into early afternoon before
wind gusts diminish as we head towards late afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Auten
LONG TERM...Geelhart
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1142 PM CST WED FEB 11 2015
.UPDATE...
823 PM CST
FOR EVENING UPDATE...
MADE A COUPLE OF MINOR CHANGES TO GOING FORECAST...NAMELY TO MOVE
TIMING OF SCATTERED SNOW SHOWERS BACK A BIT UNTIL MIDNIGHT AND
AFTER...ADJUSTED CLOUD COVER EARLIER FOR PERIOD OF CLEARING THIS
EVENING...AND LOWERED OVERNIGHT MINS JUST A DEGREE OR TWO IN A FEW
SPOTS.
ARCTIC AIR SPREADING IN FROM THE NORTHWEST THIS EVENING AS SECONDARY
COLD FRONT WAS MOVING INTO NORTHWEST IL AS OF 02Z. STRONG GRADIENT
AND STEEP LOW LEVEL LAPSE RATES WILL ALSO HELP WINDS PICK UP A BIT
OVERNIGHT...AS GRADIENT TIGHTENS AHEAD OF STRONG ARCTIC HIGH OOZING
SOUTH FROM SASKATCHEWAN/MANITOBA INTO THE NORTHERN PLAINS. TEMPS
HAVE ALREADY DROPPED INTO THE LOWER TEENS ACROSS NORTHEAST IA AND
SOUTHWEST WI...AND INTO THE LOW SINGLE DIGITS FARTHER UPSTREAM
ACROSS MINNESOTA. THIS AIR MASS WILL SPREAD INTO OUR AREA OVERNIGHT
WITH WINDS GUSTING TO AROUND 35 MPH AT TIMES IN SOME SPOTS. BASED ON
UPSTREAM TEMP TRENDS HAVE NUDGED OVERNIGHT MINS DOWN 1-2 DEGREES
MAINLY ACROSS NORTHERN IL. TEMPS NOT EXPECTED TO BUDGE UPWARD MUCH
TOMORROW DESPITE SOME SUNSHINE...WITH BLUSTERY NORTHWEST WINDS
CONTINUING TO ADVECT ARCTIC AIR ACROSS THE AREA.
CLOUDS HAVE CLEARED TEMPORARILY BEHIND AFTERNOON DISTURBANCE...
THOUGH STRONG SHORT WAVE NOTED DIGGING SOUTHEAST ACROSS MINNESOTA
WILL BRING CLOUDS AND SCATTERED SNOW SHOWERS BACK TO THE AREA FROM
ABOUT MIDNIGHT ONWARD. BASED ON TIMING IR 11-3.9 MICRON SATELLITE
IMAGERY HAVE PUSHED SNOW SHOWERS BACK A BIT IN TIMING OVER IL TO
MAINLY AFTER MIDNIGHT. WHILE COVERAGE WILL NOT BE UNIFORM...STEEP
LAPSE RATES AND COLD COLUMN TEMPS SHOULD SUPPORT FAIRLY WIDESPREAD
SNOW SHOWERS UNDER THE MID-LEVEL VORT. GOING FORECAST OF A FEW
TENTHS TO A HALF INCH IN ANY ONE SPOT APPEAR REASONABLE.
HAVE MADE NO CHANGES TO LAKE EFFECT SNOW AND ASSOCIATED WINTER
WEATHER ADVISORY FOR PORTER COUNTY. REGIONAL RADAR MOSAIC DEPICTS
INCREASING COVERAGE OF LAKE-INDUCED SNOW SHOWERS OVER WESTERN LOWER
MICHIGAN...WITH LOW LEVEL WIND FIELD EXPECTED TO VEER MORE NORTHERLY
OVERNIGHT. THIS SHOULD SUPPORT DEVELOPMENT OF STRONG SINGLE-BAND LES
PLUME INTO SOUTHWEST MI/NORTHERN IN...EVENTUALLY BACKING INTO PORTER
COUNTY DURING THE PRE-DAWN HOURS OF THURSDAY MORNING. LATEST
HIGH-RES GUIDANCE (RAP/HRRR) APPEAR STEADY WITH THEIR DEPICTION
THROUGH THEIR VALID TIMES INTO TOMORROW MORNING.
RATZER
&&
.SHORT TERM...
309 PM CST
THROUGH THURSDAY...
MULTIPLE WINTER WEATHER CONCERNS IN THE SHORT TERM...MOST
SIGNIFICANTLY WITH LAKE EFFECT SNOW LATE TONIGHT INTO THURSDAY
AFTERNOON FOR PORTER COUNTY INDIANA. HAVE ISSUED A WINTER WEATHER
ADVISORY FOR MIDNIGHT THROUGH 6PM THURSDAY EVENING FOR A COMBINATION
OF SEVERAL INCHES OF LAKE EFFECT SNOW...PLUS VERY STRONG AND NEAR
WIND ADVISORY CRITERIA WINDS THAT WILL CREATE BLOWING AND DRIFTING
SNOW AND FURTHER REDUCE VISIBILITY.
MAIN FEATURES OF NOTE THIS AFTERNOON ARE STRONG ARCTIC FRONT
TRAILING FROM CLIPPER EAST OF LAKE SUPERIOR...EXPANSIVE ~1045 MB
ARCTIC HIGH OVER CANADIAN PRAIRIES AND STOUT MID/UPPER LEVEL WAVE
DIVING FROM CANADIAN PRAIRIES INTO NORTHERN PLAINS. THE ARCTIC FRONT
HAS PUSHED THROUGH THE AREA...SO TEMPERATURES WILL FALL STEADILY
THROUGH THURSDAY MORNING AS A PUNCH OF 850 MB TEMPERATURES AT OR
JUST BELOW -20C ARRIVE BY EARLY THURSDAY. AFOREMENTIONED UPPER
WAVE...WITH ASSOCIATED STRONG FORCING DESPITE SOMEWHAT LIMITED
MOISTURE...SHOULD TOUCH OFF AT LEAST SCATTERED SNOW SHOWERS EVEN FOR
AREAS AWAY FROM LAKE MICHIGAN. THESE SNOW SHOWERS SHOULD PROGRESS
SOUTHEAST WITH THE VORT PATH LATE THIS EVENING THROUGH THE
OVERNIGHT...EXITING THE SOUTHERN CWA BY EARLY THURSDAY. HAVE BUMPED
UP POPS TO MID/HIGH CHANCE WHERE CONFIDENCE IS HIGHER ON BETTER SNOW
SHOWER COVERAGE AND BROAD BRUSHED LIGHT SNOW ACCUMULATIONS. THIS
APPEARS TO BE A SCENARIO WHERE NOT ALL LOCATIONS WILL SEE MEASURABLE
SNOW OR EVEN A DUSTING...BUT SOME SPOTS COULD SEE A HALF INCH OR SO.
HIGH RATIO ARCTIC AIR MASS WILL FLUFF UP WHATEVER QPF CAN BE
SQUEEZED OUT.
NOW ONTO THE LAKE EFFECT SETUP...MODEL SOUNDINGS SUGGEST VERY
IMPRESSIVE PARAMETERS TAKING SHAPE WITH INVERSION HEIGHTS AT OR
SLIGHTLY ABOVE 10KFT...DELTA TS OVER 20C AND AT POSSIBLY UPWARDS OF
800 J/KG LAKE INDUCED CAPE IN HEART OF BAND. AS PARAMETERS
IMPROVE...BOUNDARY LAYER WINDS WILL BE STRENGTHENING...WHICH COULD
AFFECT BAND ORGANIZATION FOR A TIME. ALSO...INITIALLY...WINDS WILL
BE WEST-NORTHWEST THROUGH FIRST PART OF TONIGHT...KEEPING ACTIVITY
MAINLY EAST OF PORTER COUNTY. AS STRONG UPPER VORT MAX PUSHES ACROSS
AREA WITH ENHANCED PUSH OF COLD AIR AS WELL AS SFC TROUGH
PASSAGE...WINDS WILL SHIFT TO NORTH-NORTHWEST LATE TONIGHT INTO
THURSDAY MORNING...LIKELY BRINGING AT LEAST NORTHEAST PORTER COUNTY
INTO PERIODS OF MODERATE TO EVEN HEAVY LAKE EFFECT SNOW SHOWERS.
AS THERE ALWAYS IS...GUIDANCE VARIES ON PLACEMENT OF BAND AND HOW
LONG IT WILL LINGER OVER AREA. OUR LOCAL MODEL ACTUALLY TAKES
LONGEST TO BRING BAND INTO PORTER BUT THEN DEPICTS A
MESOLOW/ENHANCED CONVERGENCE TO KEEP LAKE EFFECT OVER COUNTY
POSSIBLY AS LATE AS LATE THURSDAY AFTERNOON. THIS WILL BE SOMETHING
TO MONITOR. HAVE KEPT CATEGORICAL POPS THROUGH THURSDAY
AFTERNOON...BUT PEAK TIME SHOULD BE ROUGHLY 9Z TONIGHT THROUGH
17Z-18Z THURSDAY BEFORE WEAKENING TAKES PLACE OR BAND SHIFTS EAST.
DID NOT MAKE A HUGE CHANGE IN PREVIOUS FORECAST...WITH SNOW AMOUNTS
UNDER 2 INCHES IN FAR SW PORTER TO UP TO 6 INCHES IN THE NORTHEAST
NEAR LAKE MI. THERE COULD BE UP TO AN INCH OR SO IN PORTIONS OF LAKE
AND JASPER COUNTIES ADJACENT TO PORTER COUNTY. CONFIDENCE IS ONLY
MEDIUM ON TOP END AMOUNTS BECAUSE OF POTENTIAL FOR LA PORTE AND
BERRIEN COUNTIES TO RECEIVE BRUNT OF THE SNOW.
ADDING TO THE CONCERN IS THE VERY STRONG NNW WINDS THAT WILL BE
OCCURRING AS THE SNOW FALLS...WITH GUSTS ON THE LAKEFRONT POSSIBLY
AS HIGH AS 45 MPH AT TIMES THURSDAY MORNING. THIS WILL LIKELY RESULT
IN BLOWING/DRIFTING SNOW AND SUBSTANTIAL VISIBILITY REDUCTIONS WHERE
THE MODERATE TO HEAVY SNOW IS FALLING. HAVE ISSUED A WINTER WEATHER
ADVISORY AS OPPOSED TO LAKE EFFECT SNOW ADVISORY FOR PORTER COUNTY
DUE TO POTENTIAL FOR NEAR ADVISORY CRITERIA WINDS AND
BLOWING/DRIFTING ISSUES POSED BY THE WIND. FELT IT PRUDENT TO ISSUE
THE ADVISORY DESPITE SOMEWHAT LOWER CONFIDENCE IN SIGNIFICANT ACCUMS
BEING OBSERVED BECAUSE THE WINDS WILL LIKELY CAUSE HAZARDOUS
CONDITIONS EVEN WITH LIGHTER SNOW AMOUNTS. TRAVEL ON I-80 THURSDAY
MORNING COULD BECOME QUITE DICEY...SO CHECK UP ON LATEST UPDATES
BEFORE TRAVELING.
FOR THE REST OF THE AREA...THURSDAY WILL BE VERY WINDY AND
COLD...WITH HIGHS STRUGGLING TO REACH THE LOWER-MID TEENS. STRONGEST
WINDS WILL BE THURSDAY MORNING...POSSIBLY REACHING 35 TO 40 MPH AT
TIMES...BEFORE GRADUALLY DIMINISHING IN THE AFTERNOON AS THE HIGH
PRESSURE BUILDS IN. MORNING WIND CHILL VALUES ARE EXPECTED TO RANGE
FROM 5 BELOW TO 20 BELOW IN THE COLDEST SPOTS. DRESS APPROPRIATELY
IF SPENDING PROLONGED TIME OUTDOORS ON THURSDAY.
RC
&&
.LONG TERM...
335 PM CST
THURSDAY NIGHT THROUGH SUNDAY...
A COLD AND ACTIVE PATTERN WILL CONTINUE INTO NEXT WORK WEEK. PRIMARY
CONCERNS ARE: LIGHT SNOW ON FRIDAY AND FRIDAY NIGHT/EARLY
SATURDAY...BITTERLY COLD AND VERY WINDY CONDITIONS ON VALENTINES
DAY...ANOTHER POTENTIALLY SIGNIFICANT LAKE EFFECT SNOW EVENT
SATURDAY NIGHT INTO SUNDAY...AND A POSSIBLY MORE WIDESPREAD SNOW
PRODUCER MONDAY AND MONDAY NIGHT.
ARCTIC HIGH PRESSURE WILL BE OVER THE AREA THURSDAY NIGHT...BUT WARM
ADVECTION ALOFT AND INCREASING CLOUD COVER IN ADVANCE OF NEXT
CLIPPER SYSTEM WILL PREVENT TEMPERATURES FROM BOTTOMING OUT. COULD
SEE A FEW SPOTS IN NORTHERN ILLINOIS DIP TO NEAR OR JUST BELOW ZERO.
CLIPPER WILL TRACK WELL NORTH OF CWA ACROSS NORTHERN LAKES ON FRIDAY
AND BEST FORCING WILL ALSO MOVE TO THE NORTH. HOWEVER...BROAD ASCENT
IN WARM ADVECTION WING OF SYSTEM...ALONG WITH SOME HELP FROM AN
UPPER SHORT WAVE SHOULD SPREAD AN AREA OF LIGHT SNOW TOWARD AND
ACROSS CWA. HAVE INCREASED POPS SLIGHTLY...BUT CONFIDENCE IS NOT
HIGH IN ALL AREAS SEEING MEASURABLE SNOW WITH WEAK/BROAD FORCING.
WHERE IT OCCURS...COULD SEE MAYBE UP TO A HALF INCH OF SNOW. FRIDAY
WILL BE THE "WARM" DAY OF THE NEXT SEVERAL...WITH LOCAL 925/850 MB
CLIMO SUPPORTING LOW-MID 20S FOR HIGHS. HAVE SOME CONCERN WITH MODEL
SOUNDINGS SHOWING LOSS OF SATURATION IN DGZ LATER FRIDAY BUT STILL
WEAK ASCENT...WHICH COULD MAKE FREEZING DRIZZLE A POSSIBILITY. HAVE
NOT ADDED IT TO GRIDS YET.
SIMILAR SETUP TO TONIGHT WILL OCCUR FRIDAY NIGHT INTO SATURDAY WITH
VORT MAX EMBEDDED IN AMPLIFIED UPPER TROUGH PIVOTING ACROSS AREA AS
NEARLY 1050 MB ARCTIC HIGH DRIVES A PUSH OF 850 MB TEMP OF COLDER
THAN -25C INTO AREA BY SATURDAY MORNING. FORCING FROM VORT MAX AND
STEEPENING LOW LEVEL LAPSE RATES COULD AGAIN TOUCH OFF SNOW
SHOWERS BEHIND STRONG ARCTIC FRONT. 12Z GFS IS MOST BULLISH ON
THIS SCENARIO COMPARED TO OTHER MODELS...BUT IT IS A REASONABLE
DEPICTION...SO DID BUMP UP POPS TO SLIGHT/LOW END CHANCE. TIMING
OF HEART OF THERMAL TROUGH VARIED ON TODAYS GUIDANCE BUT IT WILL
BE OVERHEAD ON VALENTINES DAY...SO TEMPERATURES ARE LIKELY TO FALL
INTO SINGLE DIGITS AFTER MORNING HEIGHTS. BIGGER STORY WILL BE
WINDS GUSTING TO 30 TO 40 MPH AT TIMES...BRINGING WIND CHILLS OF
10-20 BELOW THROUGH THE AFTERNOON AND EVENING. WILL LIKELY NEED A
WIND CHILL ADVISORY LATE SATURDAY INTO SUNDAY MORNING. THE BLAST
OF COLD AIR WILL ALSO PROVIDE ANOTHER EXCELLENT TO EXTREME LAKE
EFFECT SETUP WITH MODELS SHOWING GOOD AGREEMENT ON THIS THE PAST
SEVERAL DAYS. IF AT LEAST PARTS OF NW IN GET INTO THIS
ACTION...VERY SIGNIFICANT ACCUMULATIONS ARE POSSIBLE. SOME GLOBAL
GUIDANCE/NAMELY CANADIAN...HAS FOR SEVERAL RUNS INSISTED ON BAND
DRIFTING WESTWARD SUNDAY MORNING. HIGH TEMPERATURES SUNDAY SHOULD
ONLY TOP OUT IN THE UPPER SINGLE DIGITS TO LOW/MID TEENS AS
THERMAL TROUGH GRADUALLY SLIDES EAST.
MONDAY THROUGH WEDNESDAY...
ATTENTION THEN TURNS TO MID-LEVEL ENERGY GATHERING IN
SOUTHWEST...ALONG WITH A NORTHERN STREAM WAVE DIVING INTO NORTHERN
PLAINS. MODELS ARE HAVING FITS ON WHAT DEGREE OF PHASING OCCURS
BETWEEN THE SOUTHERN AND NORTHERN STREAM AS THESE PIECES SHIFT INTO
THE CENTER OF THE COUNTRY. HOWEVER...AT LEAST A PERIOD OF WARM
ADVECTION DRIVEN SNOW IS POSSIBLE MONDAY OR MONDAY NIGHT. HAVE
LIKELY POPS IN SOUTHERN THIRD OF CWA FOR NOW ON MONDAY NIGHT. THIS
PERIOD CERTAINLY BEARS WATCHING...AS SOME ENSEMBLE MEMBERS HAVE
OFFERED POTENTIAL FOR A MORE SIGNIFICANT SYSTEM TO IMPACT OUR
REGION. ANOTHER SHOT OF BITTERLY COLD AIR WILL ARRIVE BEHIND
WHATEVER HAPPENS MONDAY/MONDAY NIGHT.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* CHANCE OF SNOW SHOWERS/IFR VIS OVERNIGHT.
* STRONG/GUSTY NORTHWEST WINDS THRU THURSDAY AFTERNOON. CMS
//DISCUSSION...UPDATED 06Z...
A SECONDARY COLD FRONT/TROUGH WILL BE MOVING SOUTH ACROSS THE
TERMINALS OVERNIGHT AND WITH IT THE POTENTIAL FOR SNOW SHOWERS
THAT MAY DROP VISIBILITIES TO IFR. THE STRONGEST OF THESE SNOW
SHOWERS CURRENTLY ARE MOVING ACROSS SOUTHWEST WI AND NORTHEAST IA.
HOW FAR EAST THESE EXTEND...INCLUDING INTO THE CHICAGO AREA TAFS
IS A BIT UNCERTAIN BUT MAINTAINED TEMPO WITH TWEAKED TIMING. MID
CLOUDS CURRENTLY PUSHING ACROSS THE AREA WILL LOWER TO 3-5KFT WITH
MVFR CIGS WITH ANY SNOW SHOWERS. CIGS LIKELY TO REMAIN VFR INTO
THURSDAY MORNING...THOUGH SOME MVFR IS POSSIBLE.
LAKE EFFECT SNOW WILL CONTINUE TO DEVELOP OVERNIGHT AND SLOWLY
MOVE WEST INTO NORTHWEST INDIANA THURSDAY MORNING. MAINTAINED
MENTION AT GYY...BUT ITS POSSIBLE THE LAKE EFFECT SNOW WILL REMAIN
JUST EAST OF GYY. AT THIS POINT...TOO CLOSE TO CALL FOR GYY. THIS
LAKE EFFECT SNOW IS NOT EXPECTED TO MOVE ANY FURTHER WEST THAN
GYY.
NORTHWEST WINDS HAVE DIMINISHED SOME THIS EVENING WITH SOME AREAS
NOT SHOWING GUSTS. EXPECT WINDS TO SLOWLY INCREASE AS LOWER CLOUDS
AND COLDER AIR ARRIVE. STILL APPEARS THE STRONG SPEEDS/GUSTS WILL
OCCUR FROM JUST BEFORE DAYBREAK THROUGH LATE MORNING...THEN SPEEDS
WILL SLOWLY BUT STEADILY DIMINISH THURSDAY AFTERNOON...BECOMING
LIGHT WESTERLY THURSDAY EVENING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW FOR SNOW SHOWERS/IFR VIS OVERNIGHT.
* MEDIUM FOR WINDS THRU THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...PERIOD OF -SHSN WITH IFR VSBY PROBABLE.
SATURDAY...CHANCE OF FLURRIES AND MVFR CIGS. STRONG NW WINDS.
SUNDAY...VFR PROBABLE.
MONDAY...VFR DURING DAY...SNOW AND IFR AT NIGHT.
TUESDAY...MVFR CIGS POSSIBLE.
IZZI
&&
.MARINE...
233 PM CST
A SERIES OF STRONG COLD FRONTS WILL BRING PERIODS OF GALE FORCE
WINDS AND HIGH WAVES TO LAKE MICHIGAN FOR THE UPCOMING DAYS...WITH
CHANGING WINDS AS WELL. THIS WILL OCCUR TONIGHT AS STRONG HIGH
PRESSURE BUILDS ACROSS THE UPPER MIDWEST TONIGHT...WHILE LOW
PRESSURE CONTINUES EASTWARD TO THE ATLANTIC SEABOARD. AFTER A BREAK
THURSDAY NIGHT INTO FRIDAY AS THE HIGH PASSES OVER THE
LAKE...ANOTHER LOW DIVING SOUTHEAST THROUGH ONTARIO WILL PASS OVER
THE NORTHERN TIER OF THE LAKE FRIDAY NIGHT...WITH ITS ASSOCIATED
COLD FRONT CLEARING THE SOUTH END OF THE LAKE BY SATURDAY MORNING.
STRONG HIGH PRESSURE BUILDS IN BEHIND THIS SYSTEM AS WELL...WHICH
WILL LIKELY RESULT IN ANOTHER PERIOD OF NORTHWESTERLY TO NORTHERLY
GALES ON SATURDAY. THE HIGH WILL SHIFT OVER THE LAKE SUNDAY.
AFTERWARDS...ANOTHER LOW WILL MOVE EAST THROUGH HUDSON BAY ON MONDAY
FOR A PERIOD OF SW WINDS...BUT ITS ASSOCIATED COLD FRONT WILL MOVE
OVER THE LAKE ON TUESDAY BRINGING A RETURN TO GUSTY NW WINDS.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...WINTER WEATHER ADVISORY...INZ002 UNTIL 6 PM THURSDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM THURSDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM
THURSDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 3 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL MIDNIGHT
THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1115 PM CST Wed Feb 11 2015
.UPDATE...
ISSUED AT 845 PM CST WED FEB 11 2015
Latest surface map indicating a secondary cold front was tracking
quickly southeast across southern Wisconsin through central Iowa.
North of the buondary, temperatures this evening have fallen into
the single digits above and below zero over southern Minnesota and
expect some of that very cold air to spill into our area during the
early morning hours accompanied by gusty winds and scattered flurries.
Fairly strong 3 hourly pressure rises noted just behind the fast
moving cold front which should translate into increasing northwest
winds again towards morning which will drive wind chills down to
between -10 to -15 north and from zero to -10 across the south by
dawn Thursday. Will adjust the flurry chances further to the
south and west for late tonight, otherwise, no other changes were
needed to the grids. Will have an updated ZFP out by 915 pm.
&&
.SHORT TERM...(Tonight)
ISSUED AT 303 PM CST WED FEB 11 2015
1005 mb low pressure deepening just east of Lake Superior has its
polar cold front extending southward through central IN into western
KY/TN. Overcast stratocumulus cloud deck cover central and southeast
IL with ceilings 1-3k ft. Brisk WNW winds 12-22 mph and gusts of
22-35 mph was slowly cooling temps this afternoon. Mercury readings
range from 28F at Galesburg to 46F at Mount Carmel airport. Wind
chills currently getting as cold as 15F at Galesburg, 16F in Macomb
and 17F in Bloomington. A vigorous northern stream short wave along
the ND/MN/Canadian border will dive se into central IL/IN by sunrise
and across the Ohio river valley by 18z/noon Thu. Latest forecast
models are showing some light qpf over ne counties overnight with
this short wave and bumped up pops to 20-40% in our ne counties
overnight with a dusting of snow (less than a half inch from Peoria
to Bloomington to Paris ne. Flurries possible elsewhere tonight with
mostly cloudy skies with some clearing nw of IL river later tonight
behind short wave. Lows overnight range from near 5F at Galesburg to
mid teens se of I-70. Gusty nw winds continue tonight and wind
chills get down to 10-14F below zero over northern counties later
tonight into Thu morning and still shy of wind chill advisory
criteria.
&&
.LONG TERM...(Thursday through Wednesday)
ISSUED AT 303 PM CST WED FEB 11 2015
Ridging over the Pacific coast keeping much of the Midwest in
modified northwesterly flow and in line for a few rounds of Arctic
air moving into the region through the forecast. Precip in the way
of light snow/flurries making a return over the weekend...but the
next big chance for a system is reserved for the beginning of the
work week. Tomorrow...behind today`s front, temps signif colder with
highs only climbing into the teens at the sfc with -19C to -20C at
850mb. Even with partly cloudy skies early clearing to mostly sunny
by the afternoon...Cold temps remain. Brisk winds out of the north
in the 15 to 25mph range will keep the wind chills in the single
digits above and below zero throughout the day. Brief round of high
pressure dominance Thursday night with light winds under the ridge
axis...shifting to the east for Friday and southerly winds kick in
yet again, resulting in warmer highs for Friday. NAM and GFS in
agreement with the production of some QPF for Saturday as a wave
dives into the broader scale trof over the Great Lakes aloft. Not a
lot of confidence at this point in such a fast moving system without
good separation from the main wave...and keeping the pops very low
at this point for Saturday. Significant cold air on the way behind
it though, and temps dropping Sat night and into Sunday with the
cold snap. Increasing pressure gradient btwn sfc systems resulting
in stronger winds with the cold air and apparent temps drop into
wind chill advisory criteria for Sunday morning, though too far out
to consider the headline just yet.
Monday another system moves in out of the west/southwest and spreads
snowfall across the region. At this point in time, indications that
the forecast soundings are all below freezing and the precip will
likely be all snow. However, a lot of variables with this system,
including the WAA ahead of the low... and the track itself, with the
ECMWF having a far more southerly track leaving much of the northern
tier of the state dry. Too many variables for a strong confidence
across the board on the system to start the work week for snowfall
amounts.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1105 PM CST WED FEB 11 2015
An Arctic cold front will sweep across the area early this morning
accompanied by gusty northwest winds, scattered flurries and cigs
deteriorating to MVFR once again. Leading edge of the clouds pushing
across west central IL with another band over northeast Iowa into
south central Wisconsin. Latest guidance suggests a rapid push to
the southeast with both cloud bands as the colder air rushes in
during the early morning hours. RAP and HRRR forecast soundings
indicate the clouds should begin to push southeast out of our
area in the 16z-20z time frame as large scale subsidence/sinking
air settles in across the area in the wake of the strong upper
wave tracking to our north. We should see VFR conditions during
the afternoon although the gusty northwest winds are expected to
continue with a quick diminishing trend setting in late in the
afternoon as the center of the cold air mass settles in from the
northwest.
Look for northwest winds of 15 to 20 kts overnight with a few
gusts around 30 kts at times. Northwest to north winds are
expected across the TAF sites on Thursday with speeds of 13 to 18
kts with gusts in the 25-30 kt range into early afternoon before
wind gusts diminish as we head towards late afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Smith
SHORT TERM...07
LONG TERM...HJS
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
509 AM CST THU FEB 12 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 111 AM CST THU FEB 12 2015
TODAY:
A FAIRLY BENIGN WEATHER DAY IS EXPECTED TODAY. A BACKDOOR COLD FRONT
WILL APPROACH HALF OF THE FORECAST AREA BY MORNING AND THEN STALL OUT.
THIS BOUNDARY WILL RETURN NORTH AS A WARM FRONT THROUGH THE DAY. THE
WESTERN ZONES - LOCATIONS LIKE SYRACUSE, ELKHART, AND HUGOTON WILL BE
FIRMLY IN THE WARM SECTOR AND SHOULD SEE HIGHS IN THE UPPER 50S. FARTHER
EAST WILL BE INFLUENCED MORE BY THE COLD HIGH PRESSURE CENTER LOCATED
ACROSS THE MIDWEST AND SHOULD SEE HIGHS ONLY TOPPING OUT TO THE LOWER
40S. ELEVATED FIRE WEATHER CONDITIONS ARE NOT EXPECTED - EVEN IN THE
WARMEST LOCATIONS - AS RELATIVE HUMIDITIES WILL NOT DROP LOW ENOUGH.
NO PRECIPITATION IS EXPECTED TODAY.
TONIGHT:
A WEAK FRONT WILL MOVE ACROSS THE REGION THROUGH THE OVERNIGHT WITH
MAIN IMPACT IN THE FORM OF A WIND SHIFT. HAVE GONE WITH SLIGHTLY COOLER
LOWS AS INDICATED BY THE NAM. IN ADDITION, VERIFICATION SHOWS A SLIGHT
WARM BIAS IN THE MODELS FOR LOWS. GIVEN HOW DRY THE ATMOSPHERE IS EXPECTED
TO BE, IT WOULDN`T TAKE MUCH TO RADIATE DOWNWARD. TWO CAVEATS TO THIS
IS IF THE WINDS WILL GO LIGHT AND HOW MUCH HIGH LEVEL CIRRIFORM CLOUDS
WILL IMPACT LOWS - IF AT ALL. POPS WILL CONTINUE AT ZERO PERCENT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 238 AM CST THU FEB 12 2015
A NORTHWEST DOWNSLOPE FLOW WILL IMPROVE FRIDAY WHICH WILL ALLOW
THE COLD AIR THAT INVADED WESTERN KANSAS ON THURSDAY TO QUICKLY
ERODE FROM WEST TO EAST. GIVEN THE WARMUP FORECAST BY THE GFS AND
NAM IN THE 900MB TO 850MB LEVEL THE PREVIOUS FORECAST STILL LOOKS
ON TRACK WITH HIGH REBOUNDING BACK INTO THE UPPER 50S TO LOWER
60S. GIVEN THE EXPECTED SKY COVER WILL TREND TOWARDS THE WARMER
MAV GUIDANCE FOR HIGHS NEAR THE COLORADO BORDER.
FURTHER NORTH ON FRIDAY AN UPPER LEVEL TROUGH WILL MOVE SOUTH
ACROSS MANITOBA AND WESTERN ONTARIO. AS THIS UPPER LEVEL SYSTEM
APPROACHES THE WESTERN GREAT LAKES A COLD FRONT WILL BEGIN TO EXIT
CANADA AND BEGIN TO CROSS THE NORTHERN PLAINS. MODELS APPEAR TO BE
IN GOOD AGREEMENT WITH THE NEXT COLD FRONT CROSSING WESTERN KANSAS
EARLY SATURDAY WHICH WILL BRING AN END TO THE BRIEF WARMING TREND,
ESPECIALLY IN THE NORTH. 850MB 24HOUR TEMPERATURE TRENDS FROM 00Z
SATURDAY TO 00Z SUNDAY INDICATED A 8C TO 13C FALL IN TEMPERATURES
BEHIND THIS FRONT. 00Z 850MB TEMPERATURES AT 00Z SUNDAY ARE
FORECAST TO RANGE FROM 0C TO AROUND -5C FOR ALL BUT EXTREME
SOUTHWEST KANSAS NEAR ELKHART AND LIBERAL WHERE THE FRONTAL
PASSAGE IS EXPECTED TO OCCUR LAST. BASED ON THE COOLING EXPECTED
IN THE LOWER LEVELS ALONG WITH THE POTENTIAL FOR INCREASING STATUS
BEHIND THIS FRONT WILL TREND TOWARDS THE COOLER MET GUIDANCE FOR
HIGHS NORTH OF DODGE CITY. FURTHER SOUTH WHERE TIMING OF THE FRONT
WILL BE LATER AND SOMEWHAT UNCLEAR WILL STAY CLOSE TO THE PREVIOUS
FORECAST WITH HIGHS IN THE LIBERAL AND ELKHART AREA BEING MAINLY
IN THE MID 60S. WINDY CONDITIONS ARE ALSO EXPECTED BEHIND THIS
COLD FRONT GIVEN THE TIGHT SURFACE PRESSURE GRADIENT AND THE 0-1KM
MEAN WINDS.
COLD AIR WILL CONTINUE TO MOVE INTO WESTERN KANSAS ON SUNDAY AS
THE SURFACE RIDGE AXIS CROSSES THE CENTRAL PLAINS. ALSO ON SUNDAY
AN UPPER LEVEL RIDGE AXIS WILL AMPLIFY JUST OFF THE COAST OF
BRITISH COLUMBIA AND AN UPPER LEVEL TROUGH WILL BEGIN TO MOVE
SOUTHEAST OUT OF CANADA INTO THE PACIFIC NORTHWEST. AS THIS NEXT
UPPER LEVEL SYSTEM APPROACHES THE CENTRAL ROCKIES FROM THE WEST
THE CHANCE FOR PRECIPITATION WILL BEGIN TO IMPROVE AS WARM AIR
ADVECTION/ISENTROPIC LIFT BEGINS TO IMPROVE OVER SOUTHWEST KANSAS.
AT THIS TIME PRECIPITATION TYPE ON SUNDAY NIGHT AND EARLY MONDAY
IS STILL SOMEWHAT UNCLEAR SO WILL KEEP PRECIPITATION TYPE
RAIN/FREEZING RAIN OR SNOW. THE MODEL SOUNDINGS DO INDICATED IF
LIQUID OR FREEZING PRECIPITATION DOES DEVELOP ON MONDAY IT SHOULD
CHANGE TO ALL SNOW MONDAY NIGHT.
THERE WILL BE A CHANCE FOR SNOW THROUGH TUESDAY AFTERNOON AS THE
UPPER LEVEL TROUGH CROSSES THE CENTRAL HIGH PLAINS AND A SECONDARY
COLD FRONT CROSSES WESTERN KANSAS. 850MB TEMPERATURE TRENDS
INDICATE ANOTHER 7 TO 12C FALL BETWEEN 00Z TUESDAY AND 00Z
WEDNESDAY. ON TUESDAY NIGHT HIGH PRESSURE AT THE SURFACE WILL
BEGIN TO BUILDS INTO WESTERN KANSAS AND THE UPPER LEVEL TROUGH
MOVES INTO EASTERN KANSAS. GIVEN THE CLEARING CONDITIONS AND
DECREASING WINDS LATE TUESDAY AND TUESDAY NIGHT WILL LOWER THE
LATEST CREXTENDEDFCST_INIT MINS FOR TUESDAY NIGHT BY AT LEAST 5
DEGREES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 508 AM CST THU FEB 12 2015
HRRR APPEARS TO HAVE A DECENT HANDLE WITH THE STATUS THAT WAS
MOVING SOUTH ACROSS NORTH CENTRAL KANSAS EARLIER THIS MORNING.
FOLLOWING THE HRRR TREND AND 06Z NAM BUFR SOUNDINGS THE POTENTIAL
EXIST FOR A PERIOD OF MVFR CEILINGS AT HAYS BETWEEN 12Z AND 15Z.
ELSEWHERE MOISTURE SPREADING ACROSS WESTERN KANSAS LATER THIS
MORNING WILL TO BE AT OR ABOVE THE 800MB LEVEL SO VFR CONDITIONS
CAN BE EXPECTED TODAY. NORTHEASTERLY WINDS AT 10 TO 15 MPH WILL
GRADUALLY VEER TO THE SOUTHEAST BY 18Z, AND THEN INCREASE INTO THE
15 TO 20 KNOT RANGE BY 21Z. AFTER SUNSET THE SOUTHEAST WINDS WILL
FALL BACK INTO THE 10 TO 15 KNOT RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 47 30 60 34 / 0 0 0 0
GCK 54 30 62 33 / 0 0 0 0
EHA 59 33 64 37 / 0 0 0 0
LBL 57 31 63 34 / 0 0 0 0
HYS 39 28 57 34 / 0 0 0 0
P28 40 30 60 33 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
841 AM EST THU FEB 12 2015
.SYNOPSIS...
SNOW SHOWERS AND FRIGID ARCTIC AIR WILL PLAGUE THE UPPER OHIO
VALLEY REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHARP MIDLEVEL SHORTWAVE STARTING TO DIG INTO EASTERN OH/NW PA PER
WV LOOP. MODERATE TO HEAVY SNOW SHOWERS ARE ARRIVING ALONG WITH
IT...WITH VIS DROPPING TO 1/4 MILE IN THE HEAVIEST. HAVE UPPED
POPS TO CATEGORICAL AREAWIDE. KEPT SNOW AMOUNTS INTACT FOR NOW BUT
WILL NEED TO WATCH THESE FOR LOCALIZED HEAVIER AMOUNTS IN BANDS.
TEMPERATURES WILL BE FALLING THIS AFTERNOON IN STRONG COLD
ADVECTION...BLENDED IN LAMP GUIDANCE WITH PREVIOUS NUMBERS FOR
HOURLY DETAILS. CL
PREVIOUS DISCUSSION...
DEEPENING MIXING LEVELS AND COLD UPSLOPING FLOW OUT OF THE GREAT
LAKES WILL RESULT IN MORE SNOW SHOWERS...WITH ACCUMULATION CONCERNS
CONTINUING FOR THE RIDGES WHERE DIRECT...AND STRENGTHENING UPSLOPE
IS FORECAST TO SPAWN STRONG...BUT SHALLOW OMEGA FIELDS INTO A
FALLING DENDRITIC GROWTH ZONE. EARLY AFTERNOON APPEARS THE BEST TIME
FOR RAPID ACCUMULATION IN THOSE AREAS...WITH INCREASING SUBSIDENCE
AND DRY ADVECTION...AS EXHIBITED BY RAPID RAP AND NAM MIXING RATIO
DIMINISHMENT...PROVIDING INHIBITION THEREAFTER. THE WINTER WEATHER
ADVISORY FOR THE RIDGES HAS BEEN MAINTAINED...DESPITE RATHER LIGHT
CONSENSUS GUIDANCE TOTALS.
OTHERWISE...SNOW SQUALLS WILL LIKELY IMPACT AREAS OUTSIDE THE RIDGES
PERIODICALLY UNTIL THE AFOREMENTIONED LIMITATIONS DOMINATE.
LAST...AND DEFINITELY NOT LEAST...THIS FRONT...AS ADVERTISED...WILL
LEAD AN ARCTIC AIRMASS OVER THE REGION...WITH PERIODIC REINFORCEMENT
OCCURRING THROUGH EARLY NEXT WEEK. GIVEN UPSTREAM TEMPERATURE
READINGS AND CONSISTENT GUIDANCE OVER THE PAST FEW DAYS...HAVE
TWEAKED TONIGHTS READINGS USING ADJUSTED NAM GUIDANCE PRIMARILY.
SUFFICIENT SUSTAINED WIND WITH THAT TEMPERATURE FORECAST HAS
SPAWNED THE NECESSITY FOR A WIND CHILL ADVISORY...IN EFFECT FOR
TONIGHT AND FRIDAY MORNING. -10 TO -20 BELOW WIND CHILLS CAN BE
ANTICIPATED REGIONWIDE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
SFC HIGH PRESSURE IS FORECAST TO BRIEFLY ON FRI. TEMPERATURES WILL
RECOVER SOMEWHAT AS ANOTHER STRONG UPSTREAM SHORTWAVE INITIATES WARM
ADVECTION WITH ITS APPROACH...BUT HIGHS WILL REMAIN WELL BELOW THE
AVERAGES. THAT SHORTWAVE WILL SPAWN MORE SNOW SHOWERS ON
SATURDAY...FORECAST FOR WHICH WAS BASED ON GFS PRECIPITATION
PROBABILITIES AND AMOUNTS...AND SEND ANOTHER ARCTIC FRONT ACROSS THE
REGION WITH TEMPERATURES ON SUNDAY MORNING PROJECTED UNDER THE ZERO
MARK. WIND CHILL INDICES WILL BE DANGEROUSLY LOW...SO MORE HEADLINES
SHOULD BE ANTICIPATED. SUNDAY HIGHS WERE FORECAST ABOUT 30 DEGREES
UNDER THE AVERAGES USING WPC GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ECMWF AND GFS WERE IN VERY GOOD AGREEMENT IN DEPICTIONS OF UPPER
FLOW INTO NEXT WEEK. IN GENERAL...SOME BRIEF TEMPERATURE MODERATION
ON ZONAL TO SOUTHWEST FLOW WILL BE BOUGHT WITH LIKELY SNOW...AND
POSSIBLY RAIN SOUTH OF PIT AS AN AMPLIFYING SHORTWAVE DIGS TOWARD
THE COAST ON TUESDAY OR WEDNESDAY. PROLONGED MOISTURE ADVECTION
AND ASCENT MAY CAUSE PROBLEMS...SITUATIONAL MONITORING IS UNDERWAY.
PASSAGE OF THAT SYSTEM IS PROGGED TO USHER IN MORE COLD WITH BOTH
SOLUTIONS INDICATING DEVELOPMENT OF A BROAD...HIGH AMPLITUDE NORTH
AMERICAN TROUGH BY WEEKS END. WPC GUIDANCE WAS IN LINE WITH THESE
TRENDS AND FEW ADJUSTMENTS WERE NEEDED FOR THE LONG TERM FORECAST.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
IMMEDIATELY BEFORE 12Z TAF ISSUANCE...CEILINGS AT MANY AIRPORTS
HAVE RISEN TO VFR...ALTHOUGH THIS IS NOT EXPECTED TO LAST VERY
LONG WITH CONDITIONS THE REST OF THE NIGHT HAVING BEEN MVFR.
ALTHOUGH SNOW SHOWER COVERAGE HAS DIMINISHED ACROSS THE FORECAST
AREA AS OF 11Z...ADDITIONAL SNOW SHOWERS ARE EXPECTED TO MOVE INTO
THE REGION FROM THE NORTHWEST. STILL ANTICIPATE THAT AN AREA OF
MORE MODERATE SNOW SHOWERS WILL DEVELOP LATE MORNING INTO EARLY
AFTERNOON SOMEWHERE ALONG A LINE FROM ZZV/HLG/LBE AND TRACK TO THE
SOUTH INTO MGW. THIS REGION WOULD BE THE MOST LIKELY TO HAVE
IFR/LIFR CONDITIONS IN SNOW SQUALLS. WINDS WILL ALSO BECOME GUSTY
THROUGH MUCH OF THE DAY...AROUND 25 KTS. BOTH SNOW SHOWER COVERAGE
AND GUSTY WINDS SHOULD DIMINISH DURING THE EVENING AND OVERNIGHT
HOURS AS SURFACE RIDGE BUILDS IN FROM THE WEST.
OUTLOOK.../FRIDAY THROUGH MONDAY/...
VFR EXPECTED FRIDAY INTO FRIDAY EVENING. RESTRICTIONS ARE THEN
LIKELY FRIDAY NIGHT THROUGH SUNDAY WITH LOW PRESSURE AFFECTING THE
REGION. VFR THEN EXPECTED SUNDAY NIGHT AND MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR MDZ001.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR MDZ001.
OH...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR OHZ039>041-048>050-057>059-068-069.
PA...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR PAZ007>009-013>016-020>023-029-031-073>076.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR PAZ074-076.
WV...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR WVZ001>004-012-021>023-041.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
641 AM EST THU FEB 12 2015
.SYNOPSIS...
SNOW SHOWERS AND FRIGID ARCTIC AIR WILL PLAGUE THE UPPER OHIO
VALLEY REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE SURFACE COLD FRONT HAS COMPLETED A SWEEP OF THE UPPER OHIO
REGION WITH SNOW SHOWERS EXPECTED TO CONTINUE AS THE AXIS OF THE
DEEPENING UPPER SHORTWAVE TROUGH DIGS EASTWARD. THAT AXIS WAS OVER
LAKE MICHIGAN AS OF 08Z...AND IS PROGGED TO ARRIVE OVER THE UPPER
OHIO BY MIDDAY.
DEEPENING MIXING LEVELS AND COLD UPSLOPING FLOW OUT OF THE GREAT
LAKES WILL RESULT IN MORE SNOW SHOWERS...WITH ACCUMULATION CONCERNS
CONTINUING FOR THE RIDGES WHERE DIRECT...AND STRENGTHENING UPSLOPE
IS FORECAST TO SPAWN STRONG...BUT SHALLOW OMEGA FIELDS INTO A
FALLING DENDRITIC GROWTH ZONE. EARLY AFTERNOON APPEARS THE BEST TIME
FOR RAPID ACCUMULATION IN THOSE AREAS...WITH INCREASING SUBSIDENCE
AND DRY ADVECTION...AS EXHIBITED BY RAPID RAP AND NAM MIXING RATIO
DIMINISHMENT...PROVIDING INHIBITION THEREAFTER. THE WINTER WEATHER
ADVISORY FOR THE RIDGES HAS BEEN MAINTAINED...DESPITE RATHER LIGHT
CONSENSUS GUIDANCE TOTALS.
OTHERWISE...SNOW SQUALLS WILL LIKELY IMPACT AREAS OUTSIDE THE RIDGES
PERIODICALLY UNTIL THE AFOREMENTIONED LIMITATIONS DOMINATE.
LAST...AND DEFINITELY NOT LEAST...THIS FRONT...AS ADVERTISED...WILL
LEAD AN ARCTIC AIRMASS OVER THE REGION...WITH PERIODIC REINFORCEMENT
OCCURRING THROUGH EARLY NEXT WEEK. GIVEN UPSTREAM TEMPERATURE
READINGS AND CONSISTENT GUIDANCE OVER THE PAST FEW DAYS...HAVE
TWEAKED TONIGHTS READINGS USING ADJUSTED NAM GUIDANCE PRIMARILY.
SUFFICIENT SUSTAINED WIND WITH THAT TEMPERATURE FORECAST HAS
SPAWNED THE NECESSITY FOR A WIND CHILL ADVISORY...IN EFFECT FOR
TONIGHT AND FRIDAY MORNING. -10 TO -20 BELOW WIND CHILLS CAN BE
ANTICIPATED REGIONWIDE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
SFC HIGH PRESSURE IS FORECAST TO BRIEFLY ON FRI. TEMPERATURES WILL
RECOVER SOMEWHAT AS ANOTHER STRONG UPSTREAM SHORTWAVE INITIATES WARM
ADVECTION WITH ITS APPROACH...BUT HIGHS WILL REMAIN WELL BELOW THE
AVERAGES. THAT SHORTWAVE WILL SPAWN MORE SNOW SHOWERS ON
SATURDAY...FORECAST FOR WHICH WAS BASED ON GFS PRECIPITATION
PROBABILITIES AND AMOUNTS...AND SEND ANOTHER ARCTIC FRONT ACROSS THE
REGION WITH TEMPERATURES ON SUNDAY MORNING PROJECTED UNDER THE ZERO
MARK. WIND CHILL INDICES WILL BE DANGEROUSLY LOW...SO MORE HEADLINES
SHOULD BE ANTICIPATED. SUNDAY HIGHS WERE FORECAST ABOUT 30 DEGREES
UNDER THE AVERAGES USING WPC GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ECMWF AND GFS WERE IN VERY GOOD AGREEMENT IN DEPICTIONS OF UPPER
FLOW INTO NEXT WEEK. IN GENERAL...SOME BRIEF TEMPERATURE MODERATION
ON ZONAL TO SOUTHWEST FLOW WILL BE BOUGHT WITH LIKELY SNOW...AND
POSSIBLY RAIN SOUTH OF PIT AS AN AMPLIFYING SHORTWAVE DIGS TOWARD
THE COAST ON TUESDAY OR WEDNESDAY. PROLONGED MOISTURE ADVECTION
AND ASCENT MAY CAUSE PROBLEMS...SITUATIONAL MONITORING IS UNDERWAY.
PASSAGE OF THAT SYSTEM IS PROGGED TO USHER IN MORE COLD WITH BOTH
SOLUTIONS INDICATING DEVELOPMENT OF A BROAD...HIGH AMPLITUDE NORTH
AMERICAN TROUGH BY WEEKS END. WPC GUIDANCE WAS IN LINE WITH THESE
TRENDS AND FEW ADJUSTMENTS WERE NEEDED FOR THE LONG TERM FORECAST.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
IMMEDIATELY BEFORE 12Z TAF ISSUANCE...CEILINGS AT MANY AIRPORTS
HAVE RISEN TO VFR...ALTHOUGH THIS IS NOT EXPECTED TO LAST VERY
LONG WITH CONDITIONS THE REST OF THE NIGHT HAVING BEEN MVFR.
ALTHOUGH SNOW SHOWER COVERAGE HAS DIMINISHED ACROSS THE FORECAST
AREA AS OF 11Z...ADDITIONAL SNOW SHOWERS ARE EXPECTED TO MOVE INTO
THE REGION FROM THE NORTHWEST. STILL ANTICIPATE THAT AN AREA OF
MORE MODERATE SNOW SHOWERS WILL DEVELOP LATE MORNING INTO EARLY
AFTERNOON SOMEWHERE ALONG A LINE FROM ZZV/HLG/LBE AND TRACK TO THE
SOUTH INTO MGW. THIS REGION WOULD BE THE MOST LIKELY TO HAVE
IFR/LIFR CONDITIONS IN SNOW SQUALLS. WINDS WILL ALSO BECOME GUSTY
THROUGH MUCH OF THE DAY...AROUND 25 KTS. BOTH SNOW SHOWER COVERAGE
AND GUSTY WINDS SHOULD DIMINISH DURING THE EVENING AND OVERNIGHT
HOURS AS SURFACE RIDGE BUILDS IN FROM THE WEST.
OUTLOOK.../FRIDAY THROUGH MONDAY/...
VFR EXPECTED FRIDAY INTO FRIDAY EVENING. RESTRICTIONS ARE THEN
LIKELY FRIDAY NIGHT THROUGH SUNDAY WITH LOW PRESSURE AFFECTING THE
REGION. VFR THEN EXPECTED SUNDAY NIGHT AND MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR MDZ001.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR MDZ001.
OH...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR OHZ039>041-048>050-057>059-068-069.
PA...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR PAZ007>009-013>016-020>023-029-031-073>076.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR PAZ074-076.
WV...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR WVZ001>004-012-021>023-041.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
322 AM EST THU FEB 12 2015
.SYNOPSIS...
SNOW SHOWERS AND FRIGID ARCTIC AIR WILL PLAGUE THE UPPER OHIO
VALLEY REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE SURFACE COLD FRONT HAS COMPLETED A SWEEP OF THE UPPER OHIO
REGION WITH SNOW SHOWERS EXPECTED TO CONTINUE AS THE AXIS OF THE
DEEPENING UPPER SHORTWAVE TROUGH DIGS EASTWARD. THAT AXIS WAS OVER
LAKE MICHIGAN AS OF 08Z...AND IS PROGGED TO ARRIVE OVER THE UPPER
OHIO BY MIDDAY.
DEEPENING MIXING LEVELS AND COLD UPSLOPING FLOW OUT OF THE GREAT
LAKES WILL RESULT IN MORE SNOW SHOWERS...WITH ACCUMULATION CONCERNS
CONTINUING FOR THE RIDGES WHERE DIRECT...AND STRENGTHENING UPSLOPE
IS FORECAST TO SPAWN STRONG...BUT SHALLOW OMEGA FIELDS INTO A
FALLING DENDRITIC GROWTH ZONE. EARLY AFTERNOON APPEARS THE BEST TIME
FOR RAPID ACCUMULATION IN THOSE AREAS...WITH INCREASING SUBSIDENCE
AND DRY ADVECTION...AS EXHIBITED BY RAPID RAP AND NAM MIXING RATIO
DIMINISHMENT...PROVIDING INHIBITION THEREAFTER. THE WINTER WEATHER
ADVISORY FOR THE RIDGES HAS BEEN MAINTAINED...DESPITE RATHER LIGHT
CONSENSUS GUIDANCE TOTALS.
OTHERWISE...SNOW SQUALLS WILL LIKELY IMPACT AREAS OUTSIDE THE RIDGES
PERIODICALLY UNTIL THE AFOREMENTIONED LIMITATIONS DOMINATE.
LAST...AND DEFINITELY NOT LEAST...THIS FRONT...AS ADVERTISED...WILL
LEAD AN ARCTIC AIRMASS OVER THE REGION...WITH PERIODIC REIFORCEMENT
OCCURRING THROUGH EARLY NEXT WEEK. GIVEN UPSTREAM TEMPERATURE
READINGS AND CONSISTENT GUIDANCE OVER THE PAST FEW DAYS...HAVE
TWEAKED TONIGHTS READINGS USING ADJUSTED NAM GUIDANCE PRIMARILY.
SUFFICIENT SUSTAINED WIND WITH THAT TEMPERATURE FORECAST HAS
SPAWNED THE NECESSITY FOR A WIND CHILL ADVISORY...IN EFFECT FOR
TONIGHT AND FRIDAY MORNING. -10 TO -20 BELOW WIND CHILLS CAN BE
ANTICIPATED REGIONWIDE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
SFC HIGH PRESSURE IS FORECAST TO BRIEFLY BUILD BEHIND THE EXITING ARCTIC
COLD FRONT ON FRI. TEMPERATURES WILL RECOVER SOMEWHAT AS ANOTHER STRONG
UPSTREAM SHORTWAVE INTIATES WARM ADVECTION WITH ITS APPROACH...BUT
HIGHS WILL REMAIN WELL BELOW THE AVERAGES. THAT SHORTWAVE WILL
SPAWN MORE SNOW SHOWERS ON SATURDAY...FORECAST FOR WHICH WAS BASED
ON GFS PRECIPITATION PROBABILITIES AND AMOUNTS...AND SEND ANOTHER
ARCTIC FRONT ACROSS THE REGION WITH TEMPERATURES ON SUNDAY MORNING
PROJECTED UNDER THE ZERO MARK. WIND CHILL INDICES WILL BE DANGEROUSLY
LOW...SO MORE HEADLINES SHOULD BE ANTICIPATED. SUNDAY HIGHS WERE
FORECAST ABOUT 30 DEGREES UNDER THE AVERAGES USING WPC GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ECMWF AND GFS WERE IN VERY GOOD AGREEMENT IN DEPICTIONS OF UPPER
FLOW INTO NEXT WEEK. IN GENERAL...SOME BRIEF TEMPERATURE MODERATION
ON ZONAL TO SOUTHWEST FLOW WILL BE BOUGHT WITH LIKELY SNOW...AND
POSSIBLY RAIN SOUTH OF PIT AS AN AMPLIFYING SHORTWAVE DIGS TOWARD
THE COAST ON TUESDAY OR WEDNESDAY. PROLONGED MOISTURE ADVECTION
AND ASCENT MAY CAUSE PROBLEMS...SITUATIONAL MONITORING IS UNDERWAY.
PASSAGE OF THAT SYSTEM IS PROGGED TO USHER IN MORE COLD WITH BOTH
SOLUTIONS INDICATED DEVELOPMENT OF A BROAD...HIGH AMPLITUDE NORTH
AMERICAN TROUGH BY WEEKS END. WPC GUIDANCE WAS IN LINE WITH THESE
TRENDS AND FEW ADJUSTMENTS TO THAT DATA SET WERE NEEDED FOR THE
LONG TERM FORECAST.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
SCATTERED SNOW SHOWERS WILL CONTINUE THIS MORNING ZZV AND MGW
KEEPING MVFR CEILINGS AND THE REST OF THE TERMINALS GENERALLY
DROPPING TO IFR CEILINGS. A MORE MODERATE AREA OF SNOW SHOWERS IS
EXPECTED TO CROSS THE REGION FROM NEAR SUNRISE AT FKL TO NOON AT
MGW. ALTHOUGH IFR CONDITIONS ARE GENERALLY EXPECTED WITH THE
SNOW...CANNOT RULE OUT BRIEF LIFR CONDITIONS. WINDS WILL ALSO
BECOME GUSTY THROUGH THE REST OF THE DAY...AROUND 25 KTS. SNOW
SHOULD DIMINISH IN COVERAGE LATE AFTERNOON WITH GUSTS ENDING
DURING THE EVENING HOURS AS SURFACE RIDGE MOVES INTO THE REGION.
OUTLOOK.../FRIDAY THROUGH MONDAY/...
VFR EXPECTED FRIDAY INTO FRIDAY EVENING. RESTRICTIONS ARE THEN
LIKELY FRIDAY NIGHT THROUGH SUNDAY WITH LOW PRESSURE AFFECTING THE
REGION. VFR THEN EXPECTED SUNDAY NIGHT AND MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR MDZ001.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 1 AM EST
FRIDAY FOR MDZ001.
OH...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR OHZ039>041-048>050-057>059-068-069.
PA...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR PAZ007>009-013>016-020>023-029-031-073>076.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 1 AM EST
FRIDAY FOR PAZ074-076.
WV...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO NOON EST FRIDAY
FOR WVZ001>004-012-021>023-041.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 1 AM EST
FRIDAY FOR WVZ023-041.
&&
$$
15/33
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1227 AM EST THU FEB 12 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 419 PM EST WED FEB 11 2015
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A DEEPENING UPR
TROF OVER CENTRAL NAMERICA DOWNSTREAM OF A RDG OVER THE W. SEVERAL
SHRTWVS ARE EMBEDDED WITHIN THIS TROF...AND THEIR PRESENCE IS
RESPONSIBLE FOR 00Z-12Z H3 HGT FALLS IN EXCESS OF 200M AT YPL. THE
FIRST DISTURBANCE THAT BROUGHT THE LIGHT SN LAST NGT IS NOW MOVING E
INTO WRN QUEBEC. A SECOND SHRTWV THAT BROUGHT ANOTHER ROUND OF MORE
WDSPRD LIGHT SN THIS MRNG IS NOW MOVING TO THE E OF THE AREA...WITH
SUBSIDENCE IN ITS WAKE...WHICH LOWERED THE INVRN BASE TO H9 AT INL
AT 12Z...NOW RESTRICTING SN SHOWERS MAINLY TO AREAS NEAR LK SUP
IMPACTED BY THE COLD NW FLOW IN ITS WAKE. NW SFC WINDS HAVE BEEN
GUSTING AS HI AS 35 MPH...RESULTING IN SOME BLSN/REDUCED VSBYS.
LOOKING TO THE NW... AN EVEN STRONGER SHRTWV IS DIGGING SEWD THRU
MANITOBA AND TOWARD NW MN. 12Z H85-7 TEMPS WERE AS LO AS -30C/-28C
AT THE PAS MANITOBA WITHIN THE COLD SURGE ACCOMPANYING THIS SHRTWV.
THE 12Z RAOB AT THAT SITE ALSO SHOWED A FAIRLY MOIST LYR UP TO JUST
ABOVE H7.
MAIN FCST CONCERNS THRU THU ARE NUMEROUS AND RELATED TO GOING
HEADLINES/LES COVERAGE/AMOUNTS/WINDS AND BLSN AS WELL AS WIND CHILLS
THAT WL ACCOMPANY THIS INCOMING ARCTIC SURGE ASSOCIATED WITH
MANITOBA SHRTWV.
LATE TODAY/TNGT...SHRTWV NOW DIGGING THRU SRN MANITBOA IS FCST TO
DIVE TO NEAR THE MN ARROWHEAD BY 00Z AND INTO THE LOWER LKS BY 12Z
THU. THE ARRIVAL OF THE STRONGER DYNAMIC FORCING/DEEPER MSTR/CYC NW
VEERING N FLOW THIS EVNG ASSOCIATED WITH THIS DISTURBANCE WL BRING A
PERIOD OF LK ENHANCED SN IN AREAS FAVORED BY THESE WINDS AS THE
ACCOMPANYING CAA CAUSES H85 TEMPS TO BOTTOM OUT AS LO AS -25C TO
-27C BY 12Z THU. MIXING OF THE H925 WINDS AS HI AS 35-40 KTS WITH
THE VIGOROUS CAA WL CAUSE VERY GUSTY WINDS AND BLSN AS WELL...
ESPECIALLY IN OPEN AREAS NEAR LK SUP. STEADILY SHIFTING WINDS AND
THE ARRIVAL OF THE VERY COLD AIR THAT WL NEARLY ELIMINATE THE DGZ
AND GUSTY WINDS THAT WL FRAGMENT THE SN FLAKES AND FURTHER LOWER SN/
WATER RATIOS WL LIMIT LES AMOUNTS. THE HIER RES MODELS INDICATE THE
HEAVIEST SN WL FALL IN WRN ALGER COUNTY...WITH MORE PERSISTENT LLVL
CNVGC THERE ENHANCED BY THE PRESENCE OF A LARGE AMOUNT OF ICE BTWN
THE KEWEENAW AND MARQUETTE THAT WL ENHANCE A BIT OF A WNW LAND
BREEZE COMPONENT OFF THE W HALF OF UPR MI. THE STRONG LLVL WINDS WL
BLOW THESE SN SHOWERS FARTHER INLAND AND INTO DELTA COUNTY. THE ICE
COVER OVER FAR ERN LK SUP AND VEERING FLOW TO THE N THAT LIMITS
OVERWATER TRAJECTORY INTO LUCE COUNTY WL HAMPER SN ACCUMS OVER THE
FAR ERN CWA. THE COMBINATION OF THE STRONG WINDS/LO TEMPS FALLING
BLO ZERO WL CAUSE WIND CHILLS TO DIP AS LO AS -25F TO PERHAPS -30F.
LATE TNGT...VIGOROUS DNVA/DEEP LYR QVECTOR DVGC/STEADILY RISING H5
HGTS...FCST UP TO 100M BTWN 06Z-12Z OVER THE FAR W AT IWD...IN THE
WAKE OF THE DIGGING SHRTWV ARE FCST TO SHARPLY LOWER THE SUBSIDENCE
INVRN BASE TOWARD 2K FT AT IWD WL BRING A DIMINISHING TREND TO THE
LES. WEAKENING PRES GRADIENT/DIMINISHING LLVL WINDS FOLLOWING SHIFT
OF PRES CENTER TO THE E OF UPR MI WL CAUSE THE BLSN TO SUBSIDE A BIT
AS WELL.
THU...STEADILY RISING HGTS UNDER THE DNVA/LARGE SCALE QVECTOR DVGC
IN THE WAKE OF DEPARTING SHRTWV TOWARD THE MID ATLANTIC STATES AND
AHEAD OF SHRTWV RDG AXIS MOVING TOWARD THE UPR LKS THAT CAUSE A
CONTINUED LOWERING OF THE INVRN BASE TOWARD 2-3K FT EVEN OVER THE E
HALF LATE IN THE DAY WL BRING ABOUT A DIMINISHING TREND OF THE
LES...LATER OVER THE E. DIMINISHING/BACKING WINDS TOWARD THE NW WITH
APRCH OF SFC HI PRES RDG UNVER THE SUBSIDENCE WL CAUSE THE HEAVIER
LES OVER WRN ALGER COUNTY TO SHIFT TO THE E.
AS FOR THE HEADLINES...ALTHOUGH A GOOD DEAL OF ICE COVER IN THE LK
SUP NEARSHORE AREAS WL LIMIT SN TOTALS A BIT COMPARED TO WHAT WOULD
HAVE HAPPENED EARLY IN THE SEASON...GUSTY WINDS/BLSN EXACERBATED BY
THE NEARSHORE SN COVERED ICE WL BE SUFFICIENT TO WARRANT CONTINUED
HEADLINES. WILL CONTINUE THE WARNING FOR ALGER COUNTY GIVEN SUPPORT
FM THE HI RES MODELS FOR THE HEAVIEST QPF IN THE WESTERN PART OF
THAT COUNTY. ADDED WIND CHILL ADVYS FOR LUCE AND DICKINSON/IRON
COUNTIES WITH WIND CHILLS FALLING AS LO AS -28F IN THE PRESENCE OF
SUSTAINED N WIND NEAR 10 MPH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 500 PM EST WED FEB 11 2015
THE REGION IS NOW AMIDST AN ACTIVE PATTERN THAT WILL CONTINUE
THROUGH THE PERIOD. THIS PATTERN IS SOMEWHAT REMINISCENT TO LAST
WINTER AS A BROAD TROUGH BUILDS ACROSS EASTERN NORTH AMERICA.
CONCERNS CONTINUE TO GROW FOR POOR CONDITIONS FRIDAY NIGHT AND
SATURDAY WITH THE ARRIVAL OF SOME OF THE COLDEST AIR OF THE SEASON.
STRONG WINDS WILL LEAD TO VERY LOW VISIBILITIES ALONG LAKE
SUPERIOR...WITH BLIZZARD CONDITIONS QUITE POSSIBLE ALONG LAKE
SUPERIOR TO START THE WEEKEND.
THURSDAY NIGHT...A BROAD TROUGH CENTERED NEAR EASTERN HUDSON BAY
WILL SLOWLY SHIFT NORTHEASTWARD AS AN ASSOCIATED SFC TROUGH TRACKS
ACROSS THE LOWER GREAT LAKES. A SUBTLE RIDGE WILL SHIFT ACROSS THE
CWA THURSDAY NIGHT. HOWEVER...WITH COLD AIR LINGERING AROUND AND
INVERSION HEIGHTS REMAINING AROUND 3KFT...SOME LES WILL CONTINUE
ACROSS THE EAST BEFORE WINDS BACK TO THE SW BY DAYBREAK FRIDAY.
FRIDAY THROUGH SATURDAY...A STRENGTHENING UPPER JET COMBINED WITH A
POTENT SHORTWAVE TROUGH DIGGING SE INTO NW ONTARIO WILL INDUCE A SFC
LOW NORTH OF LAKE SUPERIOR FRIDAY MORNING. WEAK ISENTROPIC LIFT
AHEAD OF THIS LOW WILL SPREAD LIGHT SNOW ACROSS MUCH OF THE CWA
DURING THE DAY FRIDAY...WITH ACCUMULATIONS GENERALLY AROUND AN INCH.
BY EARLY-AFTERNOON...THE COLD FRONT ASSOCIATED WITH THE SFC LOW WILL
BE NEARING THE WESTERN CWA. H8 TEMPS FALLING FROM -15 TO -30C OVER
12-18 HOURS WILL ALLOW FOR A RAPID ONSET OF LAKE EFFECT SNOW FOR THE
NW-WIND SNOW BELTS ACROSS THE WEST BY LATE FRIDAY AFTERNOON. THE
WIND WILL QUICKLY BECOME NORTHERLY FOR ALL OF UPPER MI SATURDAY
EVENING AS THE SFC LOW TRACKS INTO NW LAKE HURON/GEORGIAN BAY.
TEMPERATURES WILL FALL QUICKLY...WITH HIGHS FAILING TO RISE ABOVE
ZERO FOR MOST OF THE AREA ON SATURDAY. WITH BLUSTERLY
CONDITIONS...WIND CHILLS WILL BE -20 TO -30F LATE FRIDAY NIGHT
THROUGH SATURDAY NIGHT.
THERE IS LITTLE DOUBT THAT WINDS WILL BE QUITE STRONG /GUSTING OVER
40MPH ALONG LAKE SUPERIOR/ BEHIND THIS FRONT AS AN ARCTIC HIGH OF
APPROX 1050MB BUILDS SE OUT OF SASKATCHEWAN AND THE 1005MB LOW MOVES
TOWARD THE LOWER GREAT LAKES. HOWEVER...THE STRENGTH OF THE PRESSURE
GRADIENT WILL DEPEND HEAVILY ON HOW THE UPPER JET AND MID-LEVEL
TROUGH INTERACT AS THE LOW MOVES AWAY FROM THE AREA. THE BEST
FORCING ON THE LEFT-EXIT OF THE JET LOOKS TO BE SOMEWHAT REMOVED TO
THE SOUTH OF THE MAIN SHORTWAVE ENERGY. IF THESE FEATURES CAN COME
INTO BETTER ALIGNMENT TO PRODUCE A STRONGER LOW...BLIZZARD
CONDITIONS WOULD BE LIKELY ALONG MUCH OF LAKE SUPERIOR FRIDAY NIGHT
THROUGH SATURDAY. THE AFOREMENTIONED ISSUES ALSO PRODUCE A STRONG
ISALLOBARIC WIND COMPONENT THAT IS MORE PERPENDICULAR THAN PARALLEL
TO THE GRADIENT WIND...THUS PROVIDING ONLY MARGINAL ENHANCEMENT TO
THE OVERALL WINDS.
WITH THE VERY COLD...AND RATHER DRY...ARCTIC AIR...SNOWFLAKE
PRODUCTION WILL BE DIFFICULT. THE EXPECTATIONS IS FOR VERY SMALL LOW-
RATIO SNOWFLAKES BY LATE FRIDAY NIGHT. FOR THIS REASON...SNOW
AMOUNTS ARE NOT OF UTMOST CONCERN WITH THIS SYSTEM. THE COMBINATION
OF THE STRONG WINDS AND SMALL SNOWFLAKE SIZE WILL GREATLY REDUCE
VISIBILITY. WHITE-OUT CONDITIONS ARE EXPECTED AT TIMES ALONG LAKE
SUPERIOR...ESPECIALLY SATURDAY MORNING. THE ONE MAJOR WILD CARD WILL
BE THE EVOLUTION OF THE ICE PACK ON LAKE SUPERIOR. ICE MODEL
FORECASTS INDICATE THAT TONIGHTS WINDS WILL GREATLY COMPACT THE ICE
ALONG THE SOUTHERN SHORE OF LAKE SUPERIOR. THIS WOULD PROVIDE MORE
OPEN WATER FOR LES PRODUCTION FOR THE WEEKEND. ADDITIONALLY...THE
ICE SHELF OFF SHORE WILL BE YET ANOTHER SOURCE OF SNOW FOR THE WINDS
TO BLOW AROUND NEAR THE SHORELINES.
WHILE BLIZZARD CONDITIONS ARE APPEARING MORE LIKELY FOR MUCH OF THE
KEWEENAW AND AREAS FROM BIG BAY TO GRAND MARAIS ALONG LAKE SUPERIOR
FRIDAY NIGHT THROUGH SATURDAY...HAVE DECIDED TO HOLD OFF ON ANY
HEADLINES AT THIS TIME FOR TWO REASONS. FIRST...THE MESSAGE
PERTAINING TO ONGOING ADVISORIES AND HEADLINES HIGHLIGHTING TONIGHTS
WEATHER MAY GET MIXED WITH ANY WATCHES FOR FRI NIGHT AND SAT.
SECOND...FORECASTER CONCENSUS IS TO SEE WHAT HAPPENS TONIGHT IN
ORDER TO GET A SAMPLE OF WHAT FRIDAY NIGHT AND SAT MAY HOLD. IF
CONDITIONS TONIGHT BECOME QUITE POOR...CONFIDENCE WILL SIGNIFICANTLY
INCREASE FOR BLIZZARD CONDITIONS EARLY THIS WEEKEND. ANY HEADLINES
MAY NOT BE ISSUED UNTIL THURSDAY...AND COULD SKIP ANY WATCHES AND GO
STRAIGHT TO A WARNING IF NEED BE.
SATURDAY NIGHT AND SUNDAY...LAKE EFFECT SNOW SHOWERS WILL CONTINUE
FOR THE NORTH WIND SNOW BELTS AS A WEAK SECONDARY TROUGH TRACKS
ACROSS THE AREA IN THE EVENING. A MID-LEVEL/SFC RIDGE BUILDING IN
FROM THE NORTHERN PLAINS LATE SATURDAY NIGHT WILL INCREASE
CONVERGENCE ACROSS THE EASTERN LAKE. THIS MAY LEAD TO A CONTINUED
DOMINATE LES BAND BETWEEN MARQUETTE AND MUNISING AS INVERSION
HEIGHTS REMAIN AROUND 5KFT. THIS LES WILL QUICKLY SHIFT OFF SHORE
DURING THE DAY SUNDAY AS THE RIDGE WORKS ACROSS LAKE SUPERIOR.
MONDAY THROUGH WEDNESDAY...A BROAD TROUGH MOVING IN FROM SOUTH-
CENTRAL CANADA WILL BRING SMALL CHANCES OF SNOW FOR MONDAY. THIS
TROUGH WILL AMPLIFY MONDAY NIGHT AND CROSS UPPER MI TUESDAY INTO
TUESDAY NIGHT. THIS WILL BRING ANOTHER ROUND OF BREEZY CONDITIONS
AND INCREASED LES FOR THE NW-WIND SNOW BELTS. HOWEVER...CONDITIONS
ARE NET EXPECTED TO BE AS BAD AS EARLY THIS WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1226 AM EST THU FEB 12 2015
A STRONG DISTURBANCE WITH CONSIDERABLE DYNAMIC FORCING AND DEEP
MOISTURE HAS BROUGHT AN INCREASE IN SNOW SHOWERS ACROSS THE AREA
TONIGHT WITH STRONG NNW WINDS THAT WILL CAUSE CONSIDERABLE
BLSN...IFR TO VLIFR CONDITIONS ARE EXPECTED AT ALL 3 TAF SITES. THE
MOST SEVERE WIND AND BLOWING SNOW IS EXPECTED AT SAW. WITH STRONG
SUBSIDENCE/DIMINISHING WINDS AND BLSN FOLLOWING THE PASSAGE OF THIS
DISTURBANCE...CONDITIONS WILL SLOWLY IMPROVE TO MVFR LATE TONIGHT
THROUGH THU MORNING. BACKING AND DIMINISHING WINDS AS HIGH PRES
BUILDS INTO THE AREA WILL ALLOW CONDITIONS TO IMPROVE TO VFR BY LATE
AFTERNOON OR EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST WED FEB 11 2015
ONGOING GALES/HEAVY FREEZING SPRAY WILL DIMINISH W-E LATE TONIGHT
AND THU WITH THE APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT
AND DIMINISHING WINDS/WAVES. ANOTHER ROUND OF GALES/HEAVY FREEZING
SPRAY ASSOCIATED WITH ANOTHER ARCTIC AIR INVASION WILL DEVELOP FRI
NIGHT AND PERSIST THRU SAT. NOT OUT OF THE QUESTION THERE COULD BE
SOME STORM FORCE GUSTS ON SAT...ESPECIALLY OVER THE E HALF.
LOW PRESSURE NEAR GEORGIAN BAY WILL SLIDE ACROSS NEW ENGLAND THROUGH
THURSDAY AND DEEPEN. HIGH PRESSURE OVER SASKATCHEWAN WILL THEN
SETTLE OVER THE MID MISSISSIPPI RIVER VALLEY BY THURSDAY AFTERNOON
WITH A RIDGE EXTENDING NORTHWARD ACROSS THE UPPER GREAT LAKES.
EXPECT THE RIDGE TO REACH THE LOWER GREAT LAKES ON FRIDAY AS LOW
PRESSURE MOVES FROM NORTHERN ONTARIO TO LAKE SUPERIOR. THE LOW WILL
DEEPEN AS IT REACHES THE LOWER GREAT LAKES ON SATURDAY AND JUST OFF
THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE BUILDING FROM CENTRAL
CANADA INTO THE NORTHERN PLAINS ON SATURDAY WILL CROSS THE GREAT
LAKES THROUGH MONDAY AS A LOW PRESSURE TROUGH REACHES THE NORTHERN
PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ THIS MORNING
FOR MIZ001>004-009-084.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ013-
085.
WIND CHILL ADVISORY UNTIL NOON CST THURSDAY FOR MIZ010-011.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ005.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ006.
WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST
THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
LSZ264-267.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ265-267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ266.
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ266.
GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ264.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST THIS MORNING FOR
LSZ263.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TK
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
947 PM EST FRI FEB 13 2015
.SYNOPSIS...ARCTIC HIGH PRESSURE SETTLES OVERHEAD TONIGHT...IN
ADVANCE OF ANOTHER ARCTIC COLD FRONT THAT WILL MOVE ACROSS OUR
REGION SATURDAY EVENING...ENHANCING AN ALREADY COLD AIRMASS.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 945 PM FRIDAY...
TONIGHT...HIGH CLOUDS HAVE MOVED OFF TO THE EAST AND SKIES HAVE
CLEARED OUT ACROSS THE CWA...AT THE SAME TIME WINDS HAVE
CALMED...SETTING UP OPTIMAL CONDITIONS FOR RADIATIONAL COOLING.
TEMPERATURES ARE CURRENTLY HOLDING IN THE MID TO UPPER 20S. DUAL
SHORTWAVES TO THE WEST...ONE PASSING NORTH OF THE AREA...AND THE
OTHER DIVING SOUTHWEST OF CENTRAL NC HAVE LEFT A VOID IN UPSTREAM
MOISTURE. ALTHOUGH FORECAST SOUNDINGS LOOK FAIRLY GOOD FOR
OROGRAPHIC CIRRUS ENHANCEMENT...THE UPPER LEVEL MOISTURE IS REALLY
LACKING AND IT WILL BE HARD TO GENERATE ANYTHING THE REST OF THE
NIGHT AND THIS MORNING ALTHOUGH THERE IS ONE AREA OF SLIGHTLY
ENHANCED MOISTURE MOVING ACROSS EASTERN KY THAT BEARS WATCHING AS IT
APPROACHES THE APPALACHIANS. AFTER MIDNIGHT...THERE IS SOME
EXPECTATION THAT WINDS WILL INCREASE A LITTLE BIT WITH A VERY
SHALLOW MIXED LAYER. RAP SOUNDINGS SHOW THIS SHOULD BE MOST
PREDOMINANT IN THE TRIAD WITH WINDS UP TO 8 KTS OR SO POSSIBLE AT
TIMES. THE UPSHOT OF THIS COULD BE A FAIRLY SPOTTY MINIMUM
TEMPERATURE MAP AS SOME AREAS MAINTAIN OPTIMAL RADIATIONAL
COOLING...AND OTHERS DO NOT. IN GENERAL EXPECT UPPER TEENS TO LOW
20S FOR LOWS BUT DO NOT BE SURPRISED TO SEE A COUPLE OF LOW TO MID
TEENS READINGS THROUGH IN THERE. -ELLIS
SATURDAY...A LEE SIDE TROUGH WILL SHARPEN IN THE AFTERNOON AS
ANOTHER ARCTIC COLD FRONT APPROACHES FROM THE NW AND THE SFC HIGH
SETS UP OVER THE NORTHERN GULF. THIS SET-UP WILL RESULT IN A
STRENGTHENING SW LOW LEVEL FLOW. IN THESE EVENTS...USUALLY SEE A
LARGER THAN NORMAL DIURNAL TEMP RECOVERY. AFTER MIN TEMPS IN THE
TEENS/LOWER 20S...POTENTIAL FOR TEMPS TO RISE A SOLID 30
DEGREES...POSSIBLY 35. HAVE GONE CONSERVATIVE WITH MAX TEMPS NEAR 50-
LOWER 50S BUT WOULD NOT BE SURPRISED TO SEE SOME MID-UPPER 50S INT EH
FAR SOUTH-SE AND MID 50S AS FAR NORTH AS RDU. EXPECT A STOUT SW WIND
15-20MPH IN THE AFTERNOON WITH GUSTS 28-33 MPH. THESE WIND
PARAMETERS ALONG WITH A DRY AIR MASS WILL RESULT IN CRITICAL FIRE
WEATHER CONDITIONS (SEE FIRE WEATHER SECTION BELOW).
MAY SEE AN INCREASE IN CLOUD COVERAGE LATE IN THE DAY AS THE ARCTIC
BOUNDARY GETS CLOSER. -WSS
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 325 PM FRIDAY...
ARCTIC FRONT...BEING PUSHED
ALONG BY A STRONG S/W CROSSING THE EASTERN LAKES INTO THE NORTHERN
MID ATLANTIC...WILL PLOW SEWD ACROSS CENTRAL NC SATURDAY EVENING.
SIMILAR TO THURSDAY`S EVENT...MAY SEE A FEW RAIN SHOWERS OR
SPRINKLES/FLURRIES ACROSS THE NE PIEDMONT AND NORTHERN COASTAL PLAIN
SATURDAY EVENING BEHIND THE FRONT. FRONTAL PASSAGE WILL BE NOTED BY
SFC WINDS VEERING TO THE NW AND GUSTING AS HIGH AS 40-45 MPH 2-4
HOURS AFTER FROPA THEN "SUBSIDE" 25-35 MPH GUSTS OVERNIGHT. THIS
FLOW WILL ADVECT A VERY COLD DRY AIR MASS INTO CENTRAL NC. APPEARS
TO BE ENOUGH MIXING TO HELP TO KEEP TEMPS UP A BIT FROM EARLIER
THINKING. MIN TEMPS 15 NW TO NEAR 20 SE. RESULTANT WIND CHILLS IN
THE SINGLE DIGITS APPEAR LIKELY...POSSIBLY CLOSE TO WIND CHILL
ADVISORY CRITERIA IN THE NORTHERN PIEDMONT.
BLUSTERY NW WINDS WILL PERSIST INTO SUNDAY MORNING-EARLY AFTERNOON
UNDER SUNNY-MOSTLY SUNNY SKIES. WITH 850MB THERMAL TROUGH OVER THE
REGION...STRONG PROBABILITY THAT MUCH OF THE REGION WILL REMAIN
BELOW FREEZING. NEXT SYSTEM EXPECTED TO APPROACH FROM THE WEST-NW
LATE SUNDAY NIGHT. BASED ON TIMING...THIS MAY INCREASE HIGH LEVEL
CLOUDS ACROSS THE REGION AFTER MIDNIGHT. STILL...WITH AN ARCTIC AIR
MASS IN PLACE AND WINDS LIKELY BECOME CALM AT SUNSET...SHOULD SEE
TEMPS FALL INTO THE 12-17 DEGREE RANGE WITH A FEW 5-10 ABOVE
POSSIBLE IN THE NORMALLY COLDER LOCATIONS OF THE NE PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 335 PM FRIDAY...
...WINTER WEATHER POSSIBLE EARLY TO MID NEXT WEEK...
MONDAY THROUGH TUESDAY NIGHT: UNSETTLE WEATHER IS EXPECTED NEXT WEEK
IN THE EARLY TO MIDWEEK TIME FRAME... AS A SERIES OF S/W
DISTURBANCES ARE EXPECTED TO CROSS THE REGION. THE FIRST LEAD
IMPULSE IS EXPECTED TO MOVE ACROSS THE AREA ON MONDAY.... AS S/W
ENERGY ACROSS THE CENTRAL PLAINS ON SUNDAY NIGHT SHIFTS QUICKLY EAST
AND ACROSS THE MID ATLANTIC REGION BY MONDAY NIGHT. THE LATEST ECMWF
AND NAM GENERATE SOME PRECIP OVER THE AREA ON MONDAY AS THIS SYSTEM
TRACK ACROSS THE REGION. HOWEVER... THE GFS CONTINUES TO TREND DRY.
GIVEN THE DRY AND COLD LOW LEVEL ANTECEDENT AIRMASS... THINK IF WE
DO INDEED GET SOME PRECIP IT SHOULD BE ON THE LIGHT SIDE. HOWEVER...
WITH HIGHS STRUGGLING TO REACH FREEZING ON MONDAY ANY PRECIP THAT
FALLS WILL LIKELY BE IN THE FORM OF SNOW. IN FACT THE LATEST ECMWF
STATISTICAL GUIDANCE GENERALLY KEEPS TEMPS BELOW FREEZING ALL DAY ON
MONDAY... WITH TEMPS STRUGGLING TO REACH 25 IN THE TRIAD. THUS...
*IF* PRECIP DOES DEVELOP WE COULD SEE PROBLEMS DEVELOP WITH EVEN
LIGHT AMOUNTS OF SNOWFALL MONDAY (BEST CHANCE ACROSS THE
WEST/NORTHWEST PIEDMONT). FOR NOW WILL JUST ADD A SLIGHT CHANCE OF
SNOW ACROSS MOST OF THE AREA ON MONDAY... AND LOWER HIGH TEMPS INTO
THE LOWER TO MID 30S.
THE BEST CHANCE FOR PRECIP IS EXPECTED ON MONDAY NIGHT INTO TUESDAY
NIGHT... AS A MUCH DEEPER/STRONGER TROUGH AMPLIFIES ACROSS THE DEEP
SOUTH HELPING TO SPAWN A SURFACE LOW NEAR THE NORTHER GULF COAST...
WITH THE LOW TRANSLATING NORTH AND EASTWARD AND OFF THE ATLANTIC
COAST BY TUESDAY. MEDIUM RANGE MODEL GUIDANCE HAS HAD A HARD TIME
WITH HOW MUCH MOISTURE WILL SPREAD ACROSS CENTRA NC. IT STILL
APPEARS THAT WE SHOULD BE SUFFICIENTLY COLD TO SUPPORT ALL SNOW
INITIALLY FOR THE ENTIRE AREA... (GIVEN PRECIP DOES SPREAD INTO OUR
REGION). OVER THE PAST FEW DAYS GUIDANCE HAS TRENDED TOWARDS A LOW
TRACK OFFSHORE AND NOT OVER CENTRAL NC OR TO THE WEST OF THE
MOUNTAINS. THUS.. FOR NOW WILL STICK CLOSE TO WPC POP FORECAST AND
TREND ANY P-TYPE CORRIDORS TO NARROW TRANSITION ZONES... THANKS TO
THE SINGLE SURFACE LOW OFFSHORE WITH THIS SYSTEM. AS CLASSIC WITH
THESE CASES... AS THE SURFACE HIGH SHIFTS OFFSHORE WE SHOULD SEE THE
RAIN/SNOW LINE PIVOT BACK TO THE NORTHWEST BY TUESDAY AFTERNOON
(HOWEVER BACK TO THE NORTHWEST IS STILL VERY MUCH UNCERTAIN)... WITH
A POSSIBLE PUSH OF ALL SNOW ACROSS THE ENTRIE AREA AS THE LOW BEGINS
TO LIFT OFF TO THE NORTH AND EAST OF THE AREA ON TUESDAY NIGHT.
GIVEN TIMING AND TRACK DIFFERENCES IN THE GUIDANCE IT IS VERY HARD
TO GIVE ANY EXPECTED SNOWFALL AMOUNTS ACROSS CENTRAL NC AT THIS
TIME. HOWEVER... CONFIDENCES IN INCREASING FOR A POTENTIAL WINTER
STORM TO AFFECT PORTIONS IF NOT ALL OF OUR AREA EARLY/MID NEXT
WEEK...WITH SNOWFALL ACCUMULATION POSSIBLE ACROSS (AT LEAST) PARTS
OF THE FORECAST AREA.
WEDNESDAY THROUGH FRIDAY: THE DEEPENING LOW WILL LIFT OFF TO THE
NORTHEAST OF THE AREA ON WEDNESDAY... WITH THE MAIN S/W TROUGH AXIS
CROSSING OUR REGION. THIS SHOULD RESULT IN A RETURN TO DRIER
WEATHER. HOWEVER... WITH A DEEP L/W TROUGH REMAINING ACROSS THE
EASTERN HALF OF THE COUNTRY... AND CENTERED OVER THE EAST COAST...
WE CAN EXPECT WELL BELOW NORMAL TEMPS... WITH THE POSSIBILITY OF
CLIPPER SYSTEMS MOVING ACROSS THE AREA. BOTH THE LATEST GFS AND
ECMWF SHOW ONE SUCH SYSTEM TRACKING ACROSS THE AREA... WITH THE VORT
CENTER TRACKING JUST TO THE SOUTH OF THE AREA LATE WEEK... WHICH
COULD RESULT IN SOME SNOW SHOWERS SOME TIME LATE WEEK. HOWEVER...
WILL KEEP THE FORECAST DRY FOR NOW... AS SUCH SYSTEMS ARE VERY HARD
TO TRACK ONLY A COUPLE DAYS OUT IN THE FORECAST.... LET ALONG DAYS 6
AND 7 OF THE FORECAST. WILL KEEP TEMPS IN THE 30S FOR HIGHS AND LOWS
IN THE TEENS AND 20S.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 630 PM FRIDAY...
A SLOWLY WEAKENING ARCTIC HIGH PRESSURE SYSTEM WILL SETTLE ACROSS
CENTRAL NC OVERNIGHT...THEN DRIFT SEWD ON SATURDAY. ASIDE FROM
PATCHES OF HIGH LEVEL CLOUDINESS...NO OTHER WEATHER CONDITIONS
EXPECTED AS WINDS WILL BECOME LIGHT AND VARIABLE.
SATURDAY...A LEE SIDE TROUGH WILL DEVELOP AND STRENGTHEN AS ANOTHER
ARCTIC FRONT APPROACHES FROM THE WEST-NW LATE IN THE DAY. THE
PRESSURE DIFFERENCE BETWEEN THE TROUGH AND THE HIGH LOCATED OVER THE
NORTHERN GULF WILL RESULT IN A BREEZY SW WIND BY LATE MORNING AND
PERSISTING THROUGH THE AFTERNOON. SUSTAINED WINDS 12-18 MPH WITH
GUSTS 26-32 MPH WILL BE COMMON.
THE STRONG ARCTIC COLD FRONT WILL PLOW THROUGH CENTRAL NC SATURDAY
EVENING. THE FRONTAL PASSAGE WILL BE NOTED BY SFC WINDS VEERING TO
THE NW AND INCREASING TO 20 MPH WITH GUSTS 35-45 MPH HIGHLY
PROBABLE. THESE STRONG WIND GUSTS WILL OCCUR WITHIN THE FIRST 2-4
HOURS AFTER FRONTAL PASSAGE. THESE CONDITIONS MAY CREATE
SIGNIFICANT CROSSWINDS ISSUES FOR RUNWAYS ORIENTATED SW-NE. A DRY
AND MUCH COLDER AIR MASS WILL OVERSPREAD THE REGION. THE BLUSTERY
NLY WINDS WITH GUSTS 20-30 MPH WILL PERSIST THROUGH MUCH OF
SUNDAY...ESPECIALLY IN THE MORNING.
THERE IS A HIGH CHANCE OF VFR CONDITIONS CONTINUING SUNDAY NIGHT
THROUGH MONDAY. A DEVELOPING LOW PRESSURE SYSTEM MAY BRING A CHANCE
OF SUB VFR CONDITIONS LATE MONDAY NIGHT THROUGH EARLY WEDNESDAY. DUE
TO MODEL INCONSISTENCIES...BELOW AVERAGE FORECAST CONFIDENCE IS
ASSIGNED TO THIS PERIOD.
&&
.FIRE WEATHER...
AS OF 330 PM FRIDAY
A STOUT SW SFC WIND WITH SUSTAINED SPEEDS 15-20 MPH
AND GUSTS AROUND 30 MPH ALONG WITH LOW RH VALUES SIGNAL THE
POTENTIAL FOR RED FLAG CONDITIONS...MAINLY ACROSS THE SOUTH HALF OF
CENTRAL NC SATURDAY AFTERNOON. IN COORDINATION WITH THE NC FORESTRY
SERVICE...A FIRE WEATHER WATCH HAS BEEN FOR SATURDAY AFTERNOON FOR
AREAS GENERALLY SOUTH OF A GOLDSBORO-SANFORD-ALBEMARLE LINE. IF
CONDITIONS EARLY SATURDAY APPEAR SIMILAR...THE WATCH WILL BE
UPGRADED TO A RED FLAG WARNING MEANING ANY FIRES THAT OCCUR MAY
QUICKLY BURN OUT OF CONTROL.
OVER THE REMAINDER OF CENTRAL NC...AN INCREASE FIRE DANGER STATEMENT
WILL BE IN EFFECT AS PARAMETERS WILL BE JUST SHY OF RED FLAG
CRITERIA.
ESSENTIALLY...ANY OUTDOOR BURNING SHOULD BE DELAYED UNTIL LESS
VOLATILE CONDITIONS OCCUR.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH SATURDAY AFTERNOON FOR NCZ042-73>078-083>086-088-
089.
&&
$$
SYNOPSIS...RAH
NEAR TERM...ELLIS/WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
FIRE WEATHER...WSS
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
400 PM CST THU FEB 12 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM CST THU FEB 12 2015
SNOW ENDING THIS EVENING SOUTHEAST AND LIGHT SNOW ON FRIDAY
HIGHLIGHT THE SHORT TERM.
LIGHT SNOW FOCUSED ACROSS THE JAMES RIVER VALLEY AS OF 2130 UTC
WILL CONTINUE TO QUICKLY DIMINISH BY EARLY THIS EVENING BASED UPON
RADAR TRENDS AND THE 19 UTC HRRR SIMULATED REFLECTIVITY. THE 12
AND INCOMING 18 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN AGREEMENT
ON A BAND OF LIGHT SNOW DEVELOPING ACROSS NORTHWEST AND CENTRAL
NORTH DAKOTA DURING THE DAY ON FRIDAY IN ASSOCIATION WITH THE
BAROCLINIC ZONE ON THE LEADING EDGE OF THE NEXT ARCTIC HIGH THAT
WILL PROPAGATE INTO THE NORTHERN PLAINS FRIDAY AFTERNOON AND
EVENING. SNOWFALL AMOUNTS OF LESS THAN ONE INCH ARE EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM CST THU FEB 12 2015
A COLD FRONT IS EXPECTED TO SWING THROUGH THE AREA FRIDAY. SOME
LIGHT SNOW IS POSSIBLE ALONG THE FRONT AS SURFACE LOW PRESSURE
DEVELOPS ACROSS EASTERN MONTANA. COLD CANADIAN AIR WILL THEN
FILTER INTO THE REGION FRIDAY NIGHT INTO SATURDAY. WIND CHILL
HEADLINES MAY BE NEEDED EAST OF THE MISSOURI RIVER SATURDAY.
THE LATEST 12 UTC MODELS CONTINUE THE TREND OF PREVIOUS
RUNS...WITH A SHORTWAVE AND INVERTED TROUGH SLIDING THROUGH
WESTERN AND CENTRAL NORTH DAKOTA LATE SATURDAY AFTERNOON THROUGH
SUNDAY. WIDESPREAD SNOW AMOUNTS BETWEEN ONE AND FOUR INCHES APPEAR
LIKELY BY SUNDAY EVENING. NORTHERN NORTH DAKOTA APPEARS TO BE
FAVORED TO RECEIVE THE HIGHEST SNOWFALL TOTALS WITH THIS EVENT.
SCATTERED SNOW COULD LINGER THROUGH MONDAY AS STRONG COLD AIR
ADVECTION TAKES HOLD.
THE ECMWF CONTINUES ITS DRY AND COLD FORECAST MONDAY NIGHT
THROUGH WEDNESDAY. HOWEVER THE LATEST GFS RUN BRINGS A CLIPPER
THROUGH NORTH DAKOTA WEDNESDAY AND PRODUCES SOME LIGHT SNOW. WIND
CHILL HEADLINES MAY BE NEEDED MONDAY NIGHT AND TUESDAY NIGHT FOR
AREAS EAST OF THE MISSOURI RIVER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 400 PM CST THU FEB 12 2015
MVFR STRATUS AND FLURRIES WILL CONTINUE ACROSS MUCH OF WESTERN AND
CENTRAL NORTH DAKOTA THIS AFTERNOON AND THROUGH THE NIGHT. A BAND
OF LIGHT SNOW MAY IMPACT KISN/KMOT/KBIS/KJMS FRIDAY AFTERNOON WITH
MVFR/IFR VISIBILITIES POSSIBLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...AJ
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
102 PM CST THU FEB 12 2015
.UPDATE...
ISSUED AT 103 PM CST THU FEB 12 2015
MAIN CHANGE WITH MID DAY UPDATE IS WIND CHILL HEADLINES. GENERALLY
WIND CHILL VALUES WERE 10 TO 20 BELOW AT 11 AM CST. THEREFORE
ALLOWED WIND CHILL ADVISORY TO EXPIRE.
UPDATE ISSUED AT 422 PM CST THU FEB 12 2015
FORECAST CHALLENGE FOR AM UPDATE IS CURRENT WIND CHILL HEADLINES
AND TIMING/EASTWARD EXTENT OF LIGHT SNOW MAINLY IN THE WEST THIS
EVENING AND TONIGHT. NORTHEAST ZONES HAVE CALM WINDS AND WIND CHILL
VALUES ARE BORDERLINE CRITERIA...AND ELSEWHERE RIGHT AROUND
THRESHOLD VALUE OF 25 BELOW. WILL ALLOW ADVISORY TO EXPIRE AT 12
PM OR CANCEL AFTER 11 AM OBS IF MAJORITY OF SITES ARE ABOVE 25
BELOW. HRRR IS REALLY KEEPING SNOWFALL WEST AND KEEPING MOST OF
NORTHEAST ZONES DRY. WILL AWAIT GFS/ECMWF MODELS BEFORE
CHANGING...BUT FOR NOW HAVE UPDATED THROUGH 00Z POPS AND WILL KEEP
LIKELIES ONLY IN THE WESTERN ZONES BORDERING WFO BIS. NOT SURE HOW
MUCH WILL ARRIVE IN THE RRV ON EAST.
UPDATE ISSUED AT 643 AM CST THU FEB 12 2015
NO CHANGES TO THE FORECAST THIS MORNING...WIND CHILL HEADLINES GO
THROUGH 18Z...TEMPS RANGE FROM EIGHT BELOW IN SE ND TO 27 BELOW AT
FOSSTON AND BROOKS MN. A SLOW RECOVERY WITH MAX TEMPS IN THE LATE
IN THE DAY OR NEAR MIDNIGHT AS SOUTH WINDS AND CLOUDS RAISE TEMPS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 342 AM CST THU FEB 12 2015
CHALLENGE FOR TODAY WILL BE PLACEMENT OF -SN CHANCES AS WEAK TEMP
ADVECTION INITIATES LIFT ACROSS THE NORTHERN PLAINS.
WIND CHILL HEADLINES SET TO EXPIRE AT 18Z WILL BE LEFT IN PLACE
EVEN WITH WINDS DECREASING. EXCELLENT SET UP FOR COLD
TEMPERATURES WITH THE FRESH SNOW LIGHT WINDS AND CLEAR SKIES THIS
MORNING. TEMP RECOVERY WILL BE SLOW WITH WEAK MIXING THRU EARLY
AFTN. INCREASING CLOUDS AND RETURN FLOW FROM WEST TO EAST DEVELOP
THIS AFTN WITH MODELS SLOWER AND WEAKER IN DEVELOPING WAA SNOW
BAND. KEPT THE LIKELY POPS FROM THE DVL INTO THE RRV 21Z-00Z AND
THEN TAPERING OFF CHANCES AS THE BAND MOVES EAST. THE TRENDS FROM
12Z TO 00Z AND NOW 06Z NAM CONTINUE TO BE LESSER CHANCES ACROSS
THE NORTH AND BEST CHANCE FOR SNOW IN SE ND. NOT CONFIDENT ENOUGH
TO LOWER THE LIKELY POPS IN THE NORTH AS A LOW QPF HIGH POP EVENT
POSSIBLE...NONETHELESS SNOW ACCUMULATIONS WILL JUST BE AN INCH AT
MOST.
STEADY TO INCREASING TEMPS EXPECTED TONIGHT WITH CLOUDS AND LIGHT WEST
WINDS. TEMPS EXPECTED TO CLIMB INTO THE TEENS FRIDAY AFTN AHEAD OF
THE NEXT SURGE OF ARCTIC AIR.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 342 AM CST THU FEB 12 2015
FRIDAY NIGHT FRESH ARCTIC AIRMASS SURGES SOUTH ACROSS THE FORECAST
AREA WITH 20 TO 30KTS AT 925MB FUNNELING DOWN THE VALLEY. WITH LAPSE
RATES IN THE 8 TO 10 C/KM RANGE WILL ADD CHC OF -SN AND FLURRIES
TO THE 21Z-06Z TIME FRAME.
CAA CONTINUES INTO THE FIRST HALF OF SATURDAY WITH MINIMAL TEMP
RECOVERY WITH HIGHS IN THE 5 TO 10 BELOW RANGE. SFC HIGH DRIFTS
EAST AND TEMP FALLOFF SHOULD BE QUICK ACROSS THE EAST WITH RETURN
FLOW STEADY TEMPS ACROSS THE WEST...POSSIBLY MAKING STEADY OR RISING
TEMPS OVERNIGHT ALONG AND WEST OF THE RRV.
FOR THE SUNDAY THROUGH THURSDAY PERIOD...AREA REMAINS IN
NORTH-NORTHWEST FLOW ALOFT AS STRONG 500 MB TROUGH REMAINS OVER THE
NORTHEASTERN U.S. THIS WILL KEEP TEMPS BELOW NORMAL NEXT WEEK. A
COUPLE OF WEAK UPPER LEVEL SYSTEMS WILL DROP SOUTHEAST THROUGH THE
AREA...ONE ON SUNDAY...WHICH WILL GIVE A CHANCE FOR SOME LIGHT
SNOW. BUT OVERALL PATTERN IS NOT A STORMY ONE JUST COLD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 103 PM CST THU FEB 12 2015
MOSTLY VFR CIGS THIS AFTN INTO EVENING...WITH A CHANCE FOR LIGHT
SNOW TAKING DVL DOWN TO MVFR VSBYS WITH SNOW. CONFIDENT NOT HIGH
ENOUGH FOR OTHER TAF SITE AREAS TO RECEIVE SNOW...SO WILL LEAVE
VFR WITH VFR CIGS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...JK
LONG TERM...JK/RIDDLE
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1023 AM CST THU FEB 12 2015
.UPDATE...
ISSUED AT 422 PM CST THU FEB 12 2015
FORECAST CHALLENGE FOR AM UPDATE IS CURRENT WIND CHILL HEADLINES
AND TIMING/EASTWARD EXTENT OF LIGHT SNOW MAINLY IN THE WEST THIS
EVENING AND TONIGHT. NORTHEAST ZONES HAVE CALM WINDS AND WIND CHILL
VALUES ARE BORDERLINE CRITERIA...AND ELSEWHERE RIGHT AROUND
THRESHOLD VALUE OF 25 BELOW. WILL ALLOW ADVISORY TO EXPIRE AT 12
PM OR CANCEL AFTER 11 AM OBS IF MAJORITY OF SITES ARE ABOVE 25
BELOW. HRRR IS REALLY KEEPING SNOWFALL WEST AND KEEPING MOST OF
NORTHEAST ZONES DRY. WILL AWAIT GFS/ECMWF MODELS BEFORE
CHANGING...BUT FOR NOW HAVE UPDATED THROUGH 00Z POPS AND WILL KEEP
LIKELIES ONLY IN THE WESTERN ZONES BORDERING WFO BIS. NOT SURE HOW
MUCH WILL ARRIVE IN THE RRV ON EAST.
UPDATE ISSUED AT 643 AM CST THU FEB 12 2015
NO CHANGES TO THE FORECAST THIS MORNING...WIND CHILL HEADLINES GO
THROUGH 18Z...TEMPS RANGE FROM EIGHT BELOW IN SE ND TO 27 BELOW AT
FOSSTON AND BROOKS MN. A SLOW RECOVERY WITH MAX TEMPS IN THE LATE
IN THE DAY OR NEAR MIDNIGHT AS SOUTH WINDS AND CLOUDS RAISE TEMPS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 342 AM CST THU FEB 12 2015
CHALLENGE FOR TODAY WILL BE PLACEMENT OF -SN CHANCES AS WEAK TEMP
ADVECTION INITIATES LIFT ACROSS THE NORTHERN PLAINS.
WIND CHILL HEADLINES SET TO EXPIRE AT 18Z WILL BE LEFT IN PLACE
EVEN WITH WINDS DECREASING. EXCELLENT SET UP FOR COLD
TEMPERATURES WITH THE FRESH SNOW LIGHT WINDS AND CLEAR SKIES THIS
MORNING. TEMP RECOVERY WILL BE SLOW WITH WEAK MIXING THRU EARLY
AFTN. INCREASING CLOUDS AND RETURN FLOW FROM WEST TO EAST DEVELOP
THIS AFTN WITH MODELS SLOWER AND WEAKER IN DEVELOPING WAA SNOW
BAND. KEPT THE LIKELY POPS FROM THE DVL INTO THE RRV 21Z-00Z AND
THEN TAPERING OFF CHANCES AS THE BAND MOVES EAST. THE TRENDS FROM
12Z TO 00Z AND NOW 06Z NAM CONTINUE TO BE LESSER CHANCES ACROSS
THE NORTH AND BEST CHANCE FOR SNOW IN SE ND. NOT CONFIDENT ENOUGH
TO LOWER THE LIKELY POPS IN THE NORTH AS A LOW QPF HIGH POP EVENT
POSSIBLE...NONETHELESS SNOW ACCUMULATIONS WILL JUST BE AN INCH AT
MOST.
STEADY TO INCREASING TEMPS EXPECTED TONIGHT WITH CLOUDS AND LIGHT WEST
WINDS. TEMPS EXPECTED TO CLIMB INTO THE TEENS FRIDAY AFTN AHEAD OF
THE NEXT SURGE OF ARCTIC AIR.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 342 AM CST THU FEB 12 2015
FRIDAY NIGHT FRESH ARCTIC AIRMASS SURGES SOUTH ACROSS THE FORECAST
AREA WITH 20 TO 30KTS AT 925MB FUNNELING DOWN THE VALLEY. WITH LAPSE
RATES IN THE 8 TO 10 C/KM RANGE WILL ADD CHC OF -SN AND FLURRIES
TO THE 21Z-06Z TIME FRAME.
CAA CONTINUES INTO THE FIRST HALF OF SATURDAY WITH MINIMAL TEMP
RECOVERY WITH HIGHS IN THE 5 TO 10 BELOW RANGE. SFC HIGH DRIFTS
EAST AND TEMP FALLOFF SHOULD BE QUICK ACROSS THE EAST WITH RETURN
FLOW STEADY TEMPS ACROSS THE WEST...POSSIBLY MAKING STEADY OR RISING
TEMPS OVERNIGHT ALONG AND WEST OF THE RRV.
FOR THE SUNDAY THROUGH THURSDAY PERIOD...AREA REMAINS IN
NORTH-NORTHWEST FLOW ALOFT AS STRONG 500 MB TROUGH REMAINS OVER THE
NORTHEASTERN U.S. THIS WILL KEEP TEMPS BELOW NORMAL NEXT WEEK. A
COUPLE OF WEAK UPPER LEVEL SYSTEMS WILL DROP SOUTHEAST THROUGH THE
AREA...ONE ON SUNDAY...WHICH WILL GIVE A CHANCE FOR SOME LIGHT
SNOW. BUT OVERALL PATTERN IS NOT A STORMY ONE JUST COLD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 643 AM CST THU FEB 12 2015
VFR WITH VRB WINDS FOR THE FIRST HALF OF THE DAY SOUTHERLY WINDS
DEVELOPING AS RETURN FLOW SETS UP...-SN LATE TODAY WITH MVFR CIGS
POSSIBLE THOUGH NOT CONFIDENT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016-
024-026>030-038-039-049-052>054.
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017-
022>024-027>032-040.
&&
$$
UPDATE...SPEICHER
SHORT TERM...JK
LONG TERM...JK/RIDDLE
AVIATION...JK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
957 AM EST THU FEB 12 2015
.SYNOPSIS...
COLDER WITH WIND BLOWN SNOW SHOWERS TODAY IN THE WAKE OF AN ARCTIC
FRONT CROSSING FIRST THING THIS MORNING. THIS SCENARIO REPEATS
ITSELF SATURDAY AFTERNOON AND NIGHT. LOW PRESSURE TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
945 AM UPDATE...
TRACKING A S/W TROF AND SFC FRONT TO CROSS THIS AFTN. TEMPS AHEAD
OF THIS HAVE GENERALLY BEEN STEADY STATE...EXCEPT FOR SOME RISES
WHERE HOLES IN THE CLOUDS ARE SHOWING UP. REARRANGED POPS USING
LATEST HRRR WHICH HAS A GOOD HANDLE ON THE SITUATION. ELECTED TO
CODE UP SOME ISOLATED THUNDER ALONG AND S OF I64 THIS AFTN. QUITE A
BIT OF INSTABILITY SHOWING UP...EVEN UP TO H7. IN FACT...NEGATIVE
SFC DELTA THETA E COINCIDES QUITE NICELY WITH MAX OMEGA...ALL
WITHIN DENDTRITIC SNOW GROWTH LAYER. GLANCING AT BTV SNOW SQUALL
PARAMETER ALSO STRONGLY SUGGESTS INTENSE SQUALLS THIS AFTERNOON.
TIMING FOR THIS LOOKS BE IN THE 2 TO 5 PM TIME RANGE. SO...EXPECT
SOME INTENSE SNOW SQUALLS WHICH COULD LAY DOWN COATINGS TO ONE
INCHERS ALONG WITH REDUCED VSBY. WILL LEAVE HEADLINES AS
IS...ALTHOUGH LOOKING LESS LIKELY OF MEETING CRITERIA THRESHOLDS
OUTSIDE OF THE MOUNTAINS.
PREVIOUS DISCUSSION BELOW...
SFC TEMPERATURES HAVE FALLEN BELOW FREEZING DESPITE SW FLOW AND
OVERCAST SKY AHEAD OF AN APPROACHING ARCTIC FRONT EARLY THIS
MORNING. THE AIR ALOFT IS PROGGED TO SUPPORT SNOW BUT RAIN HAS
MATERIALIZED OUT AHEAD OF THE COLD FRONT WITH H85 TEMPERATURES
PROGGED AT -6 TO -8C AND TEMPERATURES BELOW FREEZING EVEN JUST
ABOVE THE DECK. THEREFORE HAVE REVISED THE WINTER WEATHER
ADVISORIES FOR A TOUCH OF FREEZING RAIN BEFORE DAWN.
THE COLD FRONT IS ALSO ABOUT THREE HOURS BEHIND SCHEDULE WHICH
HELPED TO LEAVE THE OPENING FOR FREEZING RAIN...NOT CROSSING THE
OHIO RIVER UNTIL 09Z THIS MORNING. PRECIPITATION WITH THE FRONT HAS
BEEN LIGHT AND BRIEF.
EXPECT PRECIPITATION WITH THE FRONT TO BECOME MORE WIDESPREAD ONCE
IT HITS THE MOUNTAINS FIRST THING THIS MORNING...AND THEN UPSLOPE
FLOW IN ITS WAKE SHOULD KEEP THE SNOW SHOWERS GOING THERE.
MEANWHILE...THE STRONG UPPER LEVEL S/W TROUGH DRIVING THE ARCTIC
FRONT THROUGH THE AREA...WHICH SHOULD STILL OCCUR BY DAWN...PIVOTS
THROUGH LATE THIS MORNING AND EARLY THIS AFTERNOON. THIS WILL BRING
THE BEST OPPORTUNITY FOR ACCUMULATING SNOW SHOWERS ACROSS THE
LOWLANDS DURING THIS TIME...IN A BANDED FASHION SHIFTING SWD THROUGH
THE FCST AREA DURING THIS TIME...BEFORE EVEN FURTHER ENHANCING THE
SNOWFALL IN THE MOUNTAINS.
BASED ON THE TIMING OF THE UPPER FEATURE...AND THE MOIST LAYER
PROGGED TO BECOME VERY SHALLOW IN ITS WAKE...HAVE ENDED THE SNOWFALL
EARLIER OUT ACROSS THE LOWLANDS. IF THIS IDEA HOLDS UP...THE WINTER
WEATHER ADVISORY MAY BE ALLOWED TO END EARLY THERE. HAVE A LITTLE
LESS SNOW THIS MORNING COMPARED WITH PREVIOUS FCST GIVEN SLOWER
TRENDS...BUT OVERALL SNOWFALL AMOUNTS ARE STILL VERY CLOSE TO
PREVIOUS FCST AND NESTLED WITHIN ADVISORY VALUES FOR THE RESPECTIVE
AREAS INVOLVED.
HAVE GUSTY WINDS INTO TONIGHT BUT WITH PEAK GUSTS 25 TO 30 KTS
ACROSS THE LOWLANDS AND 35 TO 40 KTS OVER THE HIGHER TERRAIN SO NO
WIND ADVISORY IS NEEDED...BUT WIND CHILL VALUES DO GET DRIVEN DOWN
INTO THE TEENS BELOW ZERO TONIGHT IN OUR HIGHEST MOUNTAINOUS
COUNTIES. HAVE THEREFORE ISSUED WIND CHILL ADVISORIES FOR
POCAHONTAS AND RANDOLPH COUNTIES FOR TONIGHT AND FRI MORNING.
USED THE MET / NAM FOR TEMPERATURES...WHICH FALL SLOWLY THIS MORNING
AND THEN MORE STOUTLY THIS AFTERNOON AND TONIGHT...BUT HIGHS AND
LOWS ARE STILL CLOSE TO PREVIOUS FCST AND CURRENT GUIDANCE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
THURSDAY NIGHT WILL END THE SNOW SHOWERS OVER THE MOUNTAINS...BUT
WILL KEEP FLURRIES GOING WITH THE SIGNIFICANTLY COLDER AIR IN PLACE.
THIS IS ONE OF THOSE SCENARIOS WHERE FLURRIES WILL FALL IF CLOUDS
EXIST AS 850MB TEMPERATURES WILL GET INTO THE -20C RANGE. THE FIRST
ARCTIC HIGH PRESSURE SYSTEM FILTERS IN...TRIES TO CLEAR THE SKY
BRIEFLY...AND WILL BE QUICKLY EVICTED BY AN ENFORCING CLIPPER SYSTEM
RUNNING THROUGH THE GREAT LAKES. FIGURE THIS ENTIRE TRANSITION WILL
OCCUR ON THE QUICKER SIDE...SO HAVE MINIMAL CLEARING OVERALL WITH
MOISTURE FROM THE CLIPPER ARRIVING LATE FRIDAY. SNOW SHOWERS BEGIN
FRIDAY NIGHT...MOST PLENTIFUL ACROSS THE NORTHERN THIRD OF THE
CWA...AND THEN MORE FOR THE MOUNTAINS SATURDAY. EXPECTING MODEST
ACCUMULATIONS INTO SATURDAY.
NO MAJOR CHANGES TO THE TEMPERATURE FORECASTS...WITH WELL ADVERTISED
COLD AND THEN COLDER AIRMASSES SETTLING INTO PLACE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
USED A BLEND OF THE GFS/ECMWF/GEFS ENSEMBLE MEAN/ AND ECMWF ENSEMBLE
MEAN. THIS HAS ARCTIC AIR MOVING INTO THE AREA SATURDAY NIGHT AND
REMAINING ON SUNDAY WITH SOME UPSLOPE SNOW. HIGH PRESSURE THEN MOVES
OVER MONDAY. NEXT SYSTEM IS TUESDAY INTO WEDNESDAY. MODELS HAVE BEEN
WAFFLING ON WHETHER THIS SYSTEM MOVES NORTH OR SOUTH OF THE AREA.
FOR NOW...WILL INCLUDE A WARM WEDGE WITH THE SYSTEM
TUESDAY...ALTHOUGH PRECIPITATION ARRIVING MONDAY NIGHT INTO TUESDAY
MORNING COULD BE INTERESTING.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
ARCTIC FRONT WAS JUST CROSSING THE MOUNTAINS AS 12Z APPROACHED.
THIS HAD LEFT A BRIEF OPPORTUNITY FOR FZRA WHICH SHOULD BE OVER
WITH...AS COLDER AIR BEHIND THE ARCTIC FRONT ARRIVES.
LOW MVFR TO IFR CIGS...ALONG WITH BRIEF MVFR VSBY IN SNOW SHOWERS IN
THE WAKE OF THE FRONT THIS MORNING. THE SNOW SHOWERS WILL BECOME
MORE NUMEROUS DURING THE DAY AS A STRONG UPPER LEVEL SYSTEM
CROSSES. THE ATMOSPHERE WILL BE UNSTABLE THU MAINLY ON ACCOUNT OF
COLD AIR ALOFT...SO CONDITIONS WILL VARY AMONG THE BILLOWING SNOW
CLOUDS...FROM VFR OUTSIDE THE SNOW SHOWERS IN A DEEP MIXING LAYER TO
IFR IN THE HEAVIER SNOW SHOWERS...EVEN SNOW SQUALLS AND GENERALLY
BLUSTERY CONDITIONS.
THE SNOW SHOWERS WILL BEGIN TO DIMINISH MID AFTERNOON IN THE MIDDLE
OHIO VALLEY AS THE UPPER LEVEL SYSTEM MOVES ON BY. THE SNOW SHOWERS
WILL DIMINISH BY LATE AFTERNOON ACROSS THE REMAINDER OF THE WV
LOWLANDS...AND THEN GRADUALLY DIMINISH OVER THE MOUNTAINS
OVERNIGHT. CIGS WILL BE VFR AS THE SNOW SHOWERS END...BUT MAY DROP
BACK TO MVFR TOWARD DAWN FRI.
W SFC FLOW WILL BECOME W TO NW AND GRADUALLY STRENGTHEN AND BECOME
GUSTY THIS AFTERNOON WITH PEAK GUSTS OF 25 TO 30 KTS. THESE STRONG
WINDS WILL ONLY DIMINISH A LITTLE TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: TIMING OF LOWER CIGS THIS MORNING MAY VARY.
CONDITIONS WILL BECOME HIGHLY VARIABLE IN SNOW SHOWERS MIDDAY AND
AFTERNOON.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H H H H L M H M M
HTS CONSISTENCY H H H H H H H L H M H H
BKW CONSISTENCY H H H H H H M H H L L M
EKN CONSISTENCY H H H H M H H M L L M M
PKB CONSISTENCY H H H H H H H M H H H H
CKB CONSISTENCY H H H H H H M H M H H H
AFTER 12Z FRIDAY...
IFR AT TIMES SATURDAY NIGHT INTO SUNDAY IN THE WAKE OF AN ARCTIC
FRONT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR WVZ008>011-
013>020-024>040-046-047.
WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO 11 AM EST
FRIDAY FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR VAZ003-004.
&&
$$
SYNOPSIS...TRM/SL
NEAR TERM...TRM/30
SHORT TERM...SL
LONG TERM...RPY
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
942 AM EST THU FEB 12 2015
.SYNOPSIS...
ARCTIC AIR WILL MOVE INTO THE REGION TODAY...BRINGING SNOW SHOWERS
AND FALLING TEMPERATURES. HIGH PRESSURE WILL SETTLE INTO THE REGION
FOR FRIDAY...BEFORE ANOTHER COLD FRONT MOVES IN ON SATURDAY. THIS
WILL BRING MORE SNOW AND EVEN COLDER TEMPERATURES FOR THE REST OF
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW SHOWERS CONTINUE TO PROGRESS SOUTH SOUTHEAST ACROSS THE
REGION. SNOW SQUALL PARAMETER FROM THE RAP SHOWS A STRONGER SIGNAL
OVER THE NEXT SEVERAL HOURS AS IT PROGRESSES ACROSS THE SOUTHEAST
PART OF THE FORECAST AREAS. RADAR TRENDS SUGGEST THAT THERE IS
SOME ORGANIZATION STARTING TO DEVELOP IN THE STRONGER ECHOES. SO
THIS MIGHT BE THE GENESIS OF SQUALLS WHICH COULD BRING TEMPORARY
WHITEOUT CONDITIONS. IMMEDIATELY BEHIND THIS SNOW SHOWER ACTIVITY
DIMINISHES RATHER QUICKLY. LOOKS LIKE PRECIPITATION WILL COME TO
AN END SHORTLY IN WEST CENTRAL OHIO AND THIS SHOULD PROGRESS
ACROSS THE REGION THROUGH THE DAY WITH THE EXCEPTION OF FAR
WESTERN COUNTIES WHICH COULD HAVE SOME PERSISTENT ACTIVITY FROM A
STREAMER OFF LAKE MICHIGAN. WHERE FLOW IS ORIGINATING OVER THE
LOWER PENINSULA AS OPPOSED TO OFF THE LAKES...CLOUDS SHOULD START
TO DIMINISH LATER TODAY. SLOWLY FALLING TEMPERATURES WILL OCCUR
THROUGH THE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
ON THURSDAY NIGHT...SURFACE HIGH PRESSURE WILL BEGIN TO BUILD IN
FROM THE WEST. WITH COLD ADVECTION CONTINUING THROUGH FRIDAY
MORNING...TEMPERATURES WILL EASILY DROP INTO THE SINGLE
DIGITS...WITH THE POSSIBILITY FOR SOME VALUES NEAR ZERO IN THE
NORTHERN CWA. ALTHOUGH WINDS WILL BE DECREASING AS THE HIGH MOVES
IN...THERE WILL STILL BE ENOUGH WIND TO LEAD TO WIND CHILLS THAT
APPROACH ADVISORY CRITERIA IN THE NORTH AND NORTHEAST CWA. THIS IS
ENOUGH TO CONTINUE A MENTION IN THE HWO...BUT AS VALUES ONLY GET
INTO THE -4 TO -8 DEGREE RANGE FOR AN HOUR OR TWO IN THE FAR
NORTHEAST (SUCH AS THE STRETCH FROM HARDIN TO LICKING
COUNTIES)...THERE DOES NOT APPEAR TO BE ANY NEED FOR A WIND CHILL
ADVISORY.
THOUGH FRIDAY WILL BE COOL AND DRY...WINDS WILL BE SHIFTING BACK
TO THE SOUTHWEST...AS WEAK WARM ADVECTION IS EXPECTED TO BEGIN.
FROM HERE...IT APPEARS THAT THE ENTIRE WEDNESDAY-THURSDAY FORECAST
CYCLE APPEARS LIKELY TO REPEAT ITSELF AGAIN ON FRIDAY-SATURDAY.
HOWEVER...THE STARTING POINT WILL BE COOLER...LEAVING SNOW AS THE
ONLY PRECIPITATION TYPE IN THE FORECAST THROUGH FRIDAY AND
SATURDAY. THE INITIAL SHOT OF THETA-E ADVECTION ALOFT WILL BRING A
SLIGHT CHANCE FOR SOME FLURRIES ON FRIDAY AFTERNOON AND EVENING.
HOWEVER...APPRECIABLE PRECIPITATION WILL REMAIN WELL NORTH OF THE
FORECAST AREA UNTIL SATURDAY MORNING.
A STRENGTHENING SURFACE LOW IS FORECAST TO MOVE SOUTHEAST THROUGH
THE GREAT LAKES...WITH ANOTHER ARCTIC COLD FRONT PUSHING INTO THE
OHIO VALLEY DURING THE LATE MORNING AND AFTERNOON HOURS. THE TREND
WITH THE STRENGTH OF THIS FRONT AND THE POTENTIAL FOR SNOW APPEARS
TO BE SLIGHTLY UPWARD WITH THE 00Z MODEL RUNS. THE SURFACE LOW
WILL BE QUITE A BIT STRONGER THAN THE THURSDAY LOW...AND IN
ADDITION TO ANOTHER POTENTIAL VORTICITY ANOMALY...UPPER JET
SUPPORT WILL BE STRONGER AS WELL (WITH A 500MB NORTHWESTERLY STREAK
OF OVER 120 KNOTS PUSHING THROUGH NORTHERN ILLINOIS AND INTO
KENTUCKY). BUFKIT SOUNDINGS SUGGEST A LITTLE MORE INSTABILITY THAN
THE THURSDAY EVENT...AND SLIGHTLY STRONGER WIND GUSTS AS
WELL...WITH GOOD AGREEMENT ON THESE PARAMETERS ON RECENT RUNS OF
BOTH THE GFS/NAM (THOUGH THE ECMWF IS SLIGHTLY WEAKER ON THESE
FINER DETAILS...THIS COULD ALSO BE A FUNCTION OF ITS LACK OF
RESOLUTION ON AWIPS). THUS...ANOTHER ROUND OF SNOW IS EXPECTED
SATURDAY (WITH ACCUMULATIONS THAT COULD BE AN INCH OR TWO)...WITH
THE POTENTIAL FOR SNOW SQUALLS AND ALL THE USUAL HAZARDS THEY
BRING.
BY SUNDAY MORNING...FRIGID AIR WILL BE IN PLACE ACROSS THE ENTIRE
CWA...LIKELY ALSO AIDED BY A LITTLE BIT OF SNOW ON THE GROUND.
MIN TEMPS ARE EXPECTED TO RANGE FROM AROUND 5 DEGREES (FAR SOUTH)
TO -5 DEGREES (FAR NORTH). COMBINED WITH NORTHERLY FLOW OF AROUND
10 KNOTS...WIND CHILLS WILL RANGE FROM -5 DEGREES (FAR SOUTH) TO
-25 DEGREES (FAR NORTH). HEADLINES WILL LIKELY BE REQUIRED. RECORD
LOWS FOR SUNDAY (FEBRUARY 15) ARE AS FOLLOWS.
CVG...-1...2007
CMH...-4...1978
DAY...-5...2007
AS COLD ADVECTION IS EXPECTED TO CONTINUE THROUGH THE DAY ON
SUNDAY...THE DIURNAL CURVE WILL BE FAIRLY SMALL...AIDED ONLY BY
SOME SUN AS SKIES BECOME MOSTLY CLEAR. THE MAX TEMP FORECAST
RANGES FROM 5 TO 15 DEGREES. HERE ARE THE RECORD LOW MAXIMUM
TEMPERATURES FOR SUNDAY (FEBRUARY 15).
CVG...13...1920
CMH...12...1920
DAY...11...1920
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE HIGH AXIS CROSSES AND WEAKENS SIGNIFICANTLY EARLY MONDAY AND
SHOULD ALLOW FOR SOME SUN AND WEAKER WINDS FROM A SLIGHTLY LESS
COLD AIRMASS TO SEE READINGS REBOUND INTO THE 20S. FLOW WILL TURN
SOUTHWEST AND LIMIT NIGHTTIME FALLS WITH A WARM PUSH MONDAY NIGHT
AND TUESDAY AHEAD OF THE NEXT COLD FRONTAL PASSAGE.
THE NEXT SYSTEM ON TUESDAY IS BEING PROGGED TO COME FROM THE GULF
STATES AND THE TN VALLEY AND BE WELL AHEAD OF THE POSITIVE TILTED
L/W TROUGH OVER THE CENTRAL U.S. THIS LEADS ME TO NOTE THAT THE
PREVIOUS SYSTEMS PROMISING MUCH SNOW IN THE REGION WERE OF SIMILAR
ORIGIN WITH LITTLE UPPER SUPPORT. CONFIDENCE IN THE FORECAST TANKS
FOR THE LAST DAY OR SO IN THE FORECAST BUT HAS THE POTENTIAL FOR A
WINTER EVENT OVER THE REGION.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
A POTENT...BUT FAST MOVING...MID LEVEL TROUGH WILL PUSH THROUGH
THE GREAT LAKES AND OHIO VALLEY TODAY. LARGE SCALE ASCENT AHEAD OF
THIS FEATURE...ALONG WITH INCREASING INSTABILITY...WILL RESULT IN
NUMEROUS SNOW SHOWERS THIS MORNING. IN ADDITION...A FOCUSED LOW
LEVEL BOUNDARY (ARCTIC FRONT) WILL MOVE ACROSS THE TAF SITES. THIS
BOUNDARY WILL MARK AN AREA OF ENHANCED SNOW SHOWERS/SNOW SQUALLS
WITH THE POTENTIAL FOR VISIBILITIES TO DROP BRIEFLY TO A MILE OR
LESS. AVIATORS CAN EXPECT MVFR CEILINGS AND VISIBILITIES IN SNOW
SHOWERS THIS MORNING WITH IFR OR LESS CONDITIONS IN THE HEAVIER
SNOW SHOWERS/SQUALLS. ONCE THE MAIN MID LEVEL TROUGH AXIS MOVES
BY...SNOW SHOWER COVERAGE SHOULD DECREASE MARKEDLY AS LARGE SCALE
SUBSIDENCE TAKES OVER. THIS SHOULD BRING CEILINGS BACK TO VFR BY
THE AFTERNOON HOURS. AN INCREASING PRESSURE GRADIENT A DEEPER
MIXING TODAY WILL BRING GUSTY NORTHWEST WINDS OF 15 TO 20 KNOTS
WITH GUSTS AROUND 30 KNOTS.
FOR TONIGHT...AN AREA OF HIGH PRESSURE WILL MOVE TOWARD THE
REGION. WINDS WILL GRADUALLY DECREASE THIS EVENING. ANY REMAINING
STRATOCUMULUS CLOUDS SHOULD DISSIPATE WITH SOME SCT-BKN HIGH
CLOUDS STREAMING IN FROM THE NORTHWEST.
OUTLOOK...MVFR CEILINGS AND MVFR/IFR VISIBILITIES POSSIBLE SATURDAY
AND SATURDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...
SHORT TERM...HATZOS
LONG TERM...FRANKS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
608 AM EST THU FEB 12 2015
.SYNOPSIS...
ARCTIC AIR WILL MOVE INTO THE REGION TODAY...BRINGING SNOW SHOWERS
AND FALLING TEMPERATURES. HIGH PRESSURE WILL SETTLE INTO THE REGION
FOR FRIDAY...BEFORE ANOTHER COLD FRONT MOVES IN ON SATURDAY. THIS
WILL BRING MORE SNOW AND EVEN COLDER TEMPERATURES FOR THE REST OF
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED ON SURFACE OBSERVATIONS AND RECENT RAP ANALYSES...THE
LEADING EDGE OF A COLD ARCTIC AIR MASS IS NOW MOVING SOUTHWARD
ACROSS SOUTHERN LOWER MICHIGAN. THIS WILL CROSS INTO NORTHERN
OHIO IN THE NEXT FEW HOURS...WITH INCREASING CONVERGENCE LEADING
TO INCREASING SNOW SHOWER COVERAGE AND INTENSITY. EARLIER THIS
MORNING ACROSS THE ILN FORECAST AREA...SHALLOW LOW-LEVEL MOISTURE
PRODUCED DRIZZLE AND FREEZING DRIZZLE. AS CONFIRMED BY SURFACE
OBS...THERE IS NOW ENOUGH MOISTURE PRESENT TO PRODUCE CLOUD
ICE...AND LEAVE SNOW AS THE ONLY PRECIPITATION TYPE. HRRR/RAP RUNS
HAVE BEEN USED TO HELP TIME OUT THE ARCTIC FRONT...AND THUS THE
MOST LIKELY TIMING FOR THE GREATEST COVERAGE OF SNOW SHOWERS. POPS
AND WIND GRIDS HAVE BEEN REFINED IN DETAIL USING THIS INFORMATION.
THE CONCERN FOR POTENTIALLY HEAVY SNOW SHOWERS (SNOW SQUALLS)
REMAINS LEGITIMATE...WITH SEVERAL FACTORS ADDING UP TO SUGGEST
SUCH A THREAT COULD OCCUR. THE ARCTIC FRONT WILL BRING TWO CHANGES
TO THE WEATHER ON ITS OWN. THE FIRST IS A SIGNIFICANT INCREASE IN
WIND SPEED. AS THE WIND DIRECTION SHIFTS FROM WNW TO NW...WINDS
WILL BEGIN TO GUST TO AROUND 30 KNOTS. EVEN AHEAD OF THE
FRONT...SOME GUSTS INTO THE 20-25 KNOT RANGE HAVE BEEN
OBSERVED...WITH THE PRESSURE GRADIENT ALREADY BEGINNING TO
TIGHTEN. THE SECOND FACTOR IS THE RAPID DROP IN TEMPERATURES.
SURFACE THETA-E IMAGES DEPICT A VERY SHARP GRADIENT ALONG THE
FRONT...INDICATING THE STRENGTH OF THE TRANSITION. ON THE BACK
SIDE OF THE FRONT...TEMPERATURES WILL FALL THROUGH THE
DAY...FORCING THE USE OF A VERY-NON-DIURNAL TEMPERATURE TRACE. THE
COLD AND WINDY WEATHER WILL BE A BAD SET OF BACKGROUND CONDITIONS
FOR THE DEVELOPMENT OF CONVECTIVE SNOW SHOWERS...AND BUFKIT
SOUNDINGS CONTINUE TO INDICATE WEAK INSTABILITY THAT IS AT LEAST
PARTIALLY IN THE FAVORABLE DENDRITIC GROWTH ZONE (CENTERED AROUND
-15 CELSIUS)...WITH VERY STEEP LOW-LEVEL LAPSE RATES. ALTHOUGH
THIS IS PLENTY ENOUGH TO BE CONCERNED ABOUT...THERE REMAINS ONE
FINAL PIECE OF THE PUZZLE. THE MIDDLE OHIO VALLEY IS LOCATED IN
THE PATH OF AN INTENSE POTENTIAL VORTICITY ANOMALY (WITH THE 1.5
PV SURFACE GETTING AS LOW AS 800MB). THE CENTER OF THIS ANOMALY
WILL MOVE SOUTHEAST THROUGH INDIANA THIS MORNING...AND INTO
KENTUCKY BY EARLY AFTERNOON. UNDER AND AHEAD OF THIS...STABILITY
WILL BE FURTHER DECREASED...ENHANCING THE ASCENT FOR WHATEVER SNOW
SHOWERS ARE DEVELOPING ALONG THE FRONT. THE JUXTAPOSITION OF THESE
TWO FORCING MECHANISMS APPEARS MOST LIKELY TO BE MAXIMIZED OVER
THE SOUTHERN AND SOUTHEASTERN PORTIONS OF THE ILN FORECAST AREA
BETWEEN 15Z AND 19Z. THUS...WHILE THE POTENTIAL FOR HAZARDOUS SNOW
SQUALLS EXISTS ACROSS THE ENTIRE FORECAST AREA THIS MORNING...IT
IS IN THIS AREA AND TIME PERIOD WHERE THE CONCERN IS HIGHEST.
WITH BOTH FRONTAL AND UPPER FORCING QUICKLY DIMINISHING AFTER
18Z...POPS WERE REDUCED SIGNIFICANTLY IN THE SECOND HALF OF THE
DAY. EVEN IF SOME LIGHT SNOW REMAINS POSSIBLE...IT AT LEAST
APPEARS ALMOST CERTAIN THAT THE THREAT FOR ANY HEAVY SNOW SHOWERS
WILL BE ALL BUT GONE DURING THE AFTERNOON HOURS. THOUGH PUTTING
ACCUMULATION NUMBERS ON A SNOW SHOWER SCENARIO IS
DIFFICULT...ACCUMULATIONS WILL LIKELY BE A FEW TENTHS OUTSIDE OF
THE HEAVIER SHOWERS...WITH UP TO AN INCH (MAYBE A LITTLE MORE IN
ISOLATED CASES) FOR LOCATIONS THAT EXPERIENCE THE HEAVIER SQUALLS.
AFTER COLLABORATION WITH SURROUNDING FORECAST OFFICES...A SPECIAL
WEATHER STATEMENT WILL CONTINUE TO BE USED TO HIGHLIGHT THE SNOW
SQUALL THREAT. CURRENT HIGH-RES DATA SUGGESTS THAT FOR ANY GIVEN
LOCATION...THE THREAT SHOULD BE BRIEF ENOUGH TO LIMIT THE
USEFULNESS OF AN ADVISORY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
ON THURSDAY NIGHT...SURFACE HIGH PRESSURE WILL BEGIN TO BUILD IN
FROM THE WEST. WITH COLD ADVECTION CONTINUING THROUGH FRIDAY
MORNING...TEMPERATURES WILL EASILY DROP INTO THE SINGLE
DIGITS...WITH THE POSSIBILITY FOR SOME VALUES NEAR ZERO IN THE
NORTHERN CWA. ALTHOUGH WINDS WILL BE DECREASING AS THE HIGH MOVES
IN...THERE WILL STILL BE ENOUGH WIND TO LEAD TO WIND CHILLS THAT
APPROACH ADVISORY CRITERIA IN THE NORTH AND NORTHEAST CWA. THIS IS
ENOUGH TO CONTINUE A MENTION IN THE HWO...BUT AS VALUES ONLY GET
INTO THE -4 TO -8 DEGREE RANGE FOR AN HOUR OR TWO IN THE FAR
NORTHEAST (SUCH AS THE STRETCH FROM HARDIN TO LICKING
COUNTIES)...THERE DOES NOT APPEAR TO BE ANY NEED FOR A WIND CHILL
ADVISORY.
THOUGH FRIDAY WILL BE COOL AND DRY...WINDS WILL BE SHIFTING BACK
TO THE SOUTHWEST...AS WEAK WARM ADVECTION IS EXPECTED TO BEGIN.
FROM HERE...IT APPEARS THAT THE ENTIRE WEDNESDAY-THURSDAY FORECAST
CYCLE APPEARS LIKELY TO REPEAT ITSELF AGAIN ON FRIDAY-SATURDAY.
HOWEVER...THE STARTING POINT WILL BE COOLER...LEAVING SNOW AS THE
ONLY PRECIPITATION TYPE IN THE FORECAST THROUGH FRIDAY AND
SATURDAY. THE INITIAL SHOT OF THETA-E ADVECTION ALOFT WILL BRING A
SLIGHT CHANCE FOR SOME FLURRIES ON FRIDAY AFTERNOON AND EVENING.
HOWEVER...APPRECIABLE PRECIPITATION WILL REMAIN WELL NORTH OF THE
FORECAST AREA UNTIL SATURDAY MORNING.
A STRENGTHENING SURFACE LOW IS FORECAST TO MOVE SOUTHEAST THROUGH
THE GREAT LAKES...WITH ANOTHER ARCTIC COLD FRONT PUSHING INTO THE
OHIO VALLEY DURING THE LATE MORNING AND AFTERNOON HOURS. THE TREND
WITH THE STRENGTH OF THIS FRONT AND THE POTENTIAL FOR SNOW APPEARS
TO BE SLIGHTLY UPWARD WITH THE 00Z MODEL RUNS. THE SURFACE LOW
WILL BE QUITE A BIT STRONGER THAN THE THURSDAY LOW...AND IN
ADDITION TO ANOTHER POTENTIAL VORTICITY ANOMALY...UPPER JET
SUPPORT WILL BE STRONGER AS WELL (WITH A 500MB NORTHWESTERLY STREAK
OF OVER 120 KNOTS PUSHING THROUGH NORTHERN ILLINOIS AND INTO
KENTUCKY). BUFKIT SOUNDINGS SUGGEST A LITTLE MORE INSTABILITY THAN
THE THURSDAY EVENT...AND SLIGHTLY STRONGER WIND GUSTS AS
WELL...WITH GOOD AGREEMENT ON THESE PARAMETERS ON RECENT RUNS OF
BOTH THE GFS/NAM (THOUGH THE ECMWF IS SLIGHTLY WEAKER ON THESE
FINER DETAILS...THIS COULD ALSO BE A FUNCTION OF ITS LACK OF
RESOLUTION ON AWIPS). THUS...ANOTHER ROUND OF SNOW IS EXPECTED
SATURDAY (WITH ACCUMULATIONS THAT COULD BE AN INCH OR TWO)...WITH
THE POTENTIAL FOR SNOW SQUALLS AND ALL THE USUAL HAZARDS THEY
BRING.
BY SUNDAY MORNING...FRIGID AIR WILL BE IN PLACE ACROSS THE ENTIRE
CWA...LIKELY ALSO AIDED BY A LITTLE BIT OF SNOW ON THE GROUND.
MIN TEMPS ARE EXPECTED TO RANGE FROM AROUND 5 DEGREES (FAR SOUTH)
TO -5 DEGREES (FAR NORTH). COMBINED WITH NORTHERLY FLOW OF AROUND
10 KNOTS...WIND CHILLS WILL RANGE FROM -5 DEGREES (FAR SOUTH) TO
-25 DEGREES (FAR NORTH). HEADLINES WILL LIKELY BE REQUIRED. RECORD
LOWS FOR SUNDAY (FEBRUARY 15) ARE AS FOLLOWS.
CVG...-1...2007
CMH...-4...1978
DAY...-5...2007
AS COLD ADVECTION IS EXPECTED TO CONTINUE THROUGH THE DAY ON
SUNDAY...THE DIURNAL CURVE WILL BE FAIRLY SMALL...AIDED ONLY BY
SOME SUN AS SKIES BECOME MOSTLY CLEAR. THE MAX TEMP FORECAST
RANGES FROM 5 TO 15 DEGREES. HERE ARE THE RECORD LOW MAXIMUM
TEMPERATURES FOR SUNDAY (FEBRUARY 15).
CVG...13...1920
CMH...12...1920
DAY...11...1920
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE HIGH AXIS CROSSES AND WEAKENS SIGNIFICANTLY EARLY MONDAY AND
SHOULD ALLOW FOR SOME SUN AND WEAKER WINDS FROM A SLIGHTLY LESS
COLD AIRMASS TO SEE READINGS REBOUND INTO THE 20S. FLOW WILL TURN
SOUTHWEST AND LIMIT NIGHTTIME FALLS WITH A WARM PUSH MONDAY NIGHT
AND TUESDAY AHEAD OF THE NEXT COLD FRONTAL PASSAGE.
THE NEXT SYSTEM ON TUESDAY IS BEING PROGGED TO COME FROM THE GULF
STATES AND THE TN VALLEY AND BE WELL AHEAD OF THE POSITIVE TILTED
L/W TROUGH OVER THE CENTRAL U.S. THIS LEADS ME TO NOTE THAT THE
PREVIOUS SYSTEMS PROMISING MUCH SNOW IN THE REGION WERE OF SIMILAR
ORIGIN WITH LITTLE UPPER SUPPORT. CONFIDENCE IN THE FORECAST TANKS
FOR THE LAST DAY OR SO IN THE FORECAST BUT HAS THE POTENTIAL FOR A
WINTER EVENT OVER THE REGION.
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
A POTENT...BUT FAST MOVING...MID LEVEL TROUGH WILL PUSH THROUGH
THE GREAT LAKES AND OHIO VALLEY TODAY. LARGE SCALE ASCENT AHEAD OF
THIS FEATURE...ALONG WITH INCREASING INSTABILITY...WILL RESULT IN
NUMEROUS SNOW SHOWERS THIS MORNING. IN ADDITION...A FOCUSED LOW
LEVEL BOUNDARY (ARCTIC FRONT) WILL MOVE ACROSS THE TAF SITES. THIS
BOUNDARY WILL MARK AN AREA OF ENHANCED SNOW SHOWERS/SNOW SQUALLS
WITH THE POTENTIAL FOR VISIBILITIES TO DROP BRIEFLY TO A MILE OR
LESS. AVIATORS CAN EXPECT MVFR CEILINGS AND VISIBILITIES IN SNOW
SHOWERS THIS MORNING WITH IFR OR LESS CONDITIONS IN THE HEAVIER
SNOW SHOWERS/SQUALLS. ONCE THE MAIN MID LEVEL TROUGH AXIS MOVES
BY...SNOW SHOWER COVERAGE SHOULD DECREASE MARKEDLY AS LARGE SCALE
SUBSIDENCE TAKES OVER. THIS SHOULD BRING CEILINGS BACK TO VFR BY
THE AFTERNOON HOURS. AN INCREASING PRESSURE GRADIENT A DEEPER
MIXING TODAY WILL BRING GUSTY NORTHWEST WINDS OF 15 TO 20 KNOTS
WITH GUSTS AROUND 30 KNOTS.
FOR TONIGHT...AN AREA OF HIGH PRESSURE WILL MOVE TOWARD THE
REGION. WINDS WILL GRADUALLY DECREASE THIS EVENING. ANY REMAINING
STRATOCUMULUS CLOUDS SHOULD DISSIPATE WITH SOME SCT-BKN HIGH
CLOUDS STREAMING IN FROM THE NORTHWEST.
OUTLOOK...MVFR CEILINGS AND MVFR/IFR VISIBILITIES POSSIBLE SATURDAY
AND SATURDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...FRANKS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
406 AM EST THU FEB 12 2015
.SYNOPSIS...
ARCTIC AIR WILL MOVE INTO THE REGION TODAY...BRINGING SNOW SHOWERS
AND FALLING TEMPERATURES. HIGH PRESSURE WILL SETTLE INTO THE REGION
FOR FRIDAY...BEFORE ANOTHER COLD FRONT MOVES IN ON SATURDAY. THIS
WILL BRING MORE SNOW AND EVEN COLDER TEMPERATURES FOR THE REST OF
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED ON SURFACE OBSERVATIONS AND RECENT RAP ANALYSES...THE
LEADING EDGE OF A COLD ARCTIC AIR MASS IS NOW MOVING SOUTHWARD
ACROSS SOUTHERN LOWER MICHIGAN. THIS WILL CROSS INTO NORTHERN
OHIO IN THE NEXT FEW HOURS...WITH INCREASING CONVERGENCE LEADING
TO INCREASING SNOW SHOWER COVERAGE AND INTENSITY. EARLIER THIS
MORNING ACROSS THE ILN FORECAST AREA...SHALLOW LOW-LEVEL MOISTURE
PRODUCED DRIZZLE AND FREEZING DRIZZLE. AS CONFIRMED BY SURFACE
OBS...THERE IS NOW ENOUGH MOISTURE PRESENT TO PRODUCE CLOUD
ICE...AND LEAVE SNOW AS THE ONLY PRECIPITATION TYPE. HRRR/RAP RUNS
HAVE BEEN USED TO HELP TIME OUT THE ARCTIC FRONT...AND THUS THE
MOST LIKELY TIMING FOR THE GREATEST COVERAGE OF SNOW SHOWERS. POPS
AND WIND GRIDS HAVE BEEN REFINED IN DETAIL USING THIS INFORMATION.
THE CONCERN FOR POTENTIALLY HEAVY SNOW SHOWERS (SNOW SQUALLS)
REMAINS LEGITIMATE...WITH SEVERAL FACTORS ADDING UP TO SUGGEST
SUCH A THREAT COULD OCCUR. THE ARCTIC FRONT WILL BRING TWO CHANGES
TO THE WEATHER ON ITS OWN. THE FIRST IS A SIGNIFICANT INCREASE IN
WIND SPEED. AS THE WIND DIRECTION SHIFTS FROM WNW TO NW...WINDS
WILL BEGIN TO GUST TO AROUND 30 KNOTS. EVEN AHEAD OF THE
FRONT...SOME GUSTS INTO THE 20-25 KNOT RANGE HAVE BEEN
OBSERVED...WITH THE PRESSURE GRADIENT ALREADY BEGINNING TO
TIGHTEN. THE SECOND FACTOR IS THE RAPID DROP IN TEMPERATURES.
SURFACE THETA-E IMAGES DEPICT A VERY SHARP GRADIENT ALONG THE
FRONT...INDICATING THE STRENGTH OF THE TRANSITION. ON THE BACK
SIDE OF THE FRONT...TEMPERATURES WILL FALL THROUGH THE
DAY...FORCING THE USE OF A VERY-NON-DIURNAL TEMPERATURE TRACE. THE
COLD AND WINDY WEATHER WILL BE A BAD SET OF BACKGROUND CONDITIONS
FOR THE DEVELOPMENT OF CONVECTIVE SNOW SHOWERS...AND BUFKIT
SOUNDINGS CONTINUE TO INDICATE WEAK INSTABILITY THAT IS AT LEAST
PARTIALLY IN THE FAVORABLE DENDRITIC GROWTH ZONE (CENTERED AROUND
-15 CELSIUS)...WITH VERY STEEP LOW-LEVEL LAPSE RATES. ALTHOUGH
THIS IS PLENTY ENOUGH TO BE CONCERNED ABOUT...THERE REMAINS ONE
FINAL PIECE OF THE PUZZLE. THE MIDDLE OHIO VALLEY IS LOCATED IN
THE PATH OF AN INTENSE POTENTIAL VORTICITY ANOMALY (WITH THE 1.5
PV SURFACE GETTING AS LOW AS 800MB). THE CENTER OF THIS ANOMALY
WILL MOVE SOUTHEAST THROUGH INDIANA THIS MORNING...AND INTO
KENTUCKY BY EARLY AFTERNOON. UNDER AND AHEAD OF THIS...STABILITY
WILL BE FURTHER DECREASED...ENHANCING THE ASCENT FOR WHATEVER SNOW
SHOWERS ARE DEVELOPING ALONG THE FRONT. THE JUXTAPOSITION OF THESE
TWO FORCING MECHANISMS APPEARS MOST LIKELY TO BE MAXIMIZED OVER
THE SOUTHERN AND SOUTHEASTERN PORTIONS OF THE ILN FORECAST AREA
BETWEEN 15Z AND 19Z. THUS...WHILE THE POTENTIAL FOR HAZARDOUS SNOW
SQUALLS EXISTS ACROSS THE ENTIRE FORECAST AREA THIS MORNING...IT
IS IN THIS AREA AND TIME PERIOD WHERE THE CONCERN IS HIGHEST.
WITH BOTH FRONTAL AND UPPER FORCING QUICKLY DIMINISHING AFTER
18Z...POPS WERE REDUCED SIGNIFICANTLY IN THE SECOND HALF OF THE
DAY. EVEN IF SOME LIGHT SNOW REMAINS POSSIBLE...IT AT LEAST
APPEARS ALMOST CERTAIN THAT THE THREAT FOR ANY HEAVY SNOW SHOWERS
WILL BE ALL BUT GONE DURING THE AFTERNOON HOURS. THOUGH PUTTING
ACCUMULATION NUMBERS ON A SNOW SHOWER SCENARIO IS
DIFFICULT...ACCUMULATIONS WILL LIKELY BE A FEW TENTHS OUTSIDE OF
THE HEAVIER SHOWERS...WITH UP TO AN INCH (MAYBE A LITTLE MORE IN
ISOLATED CASES) FOR LOCATIONS THAT EXPERIENCE THE HEAVIER SQUALLS.
AFTER COLLABORATION WITH SURROUNDING FORECAST OFFICES...A SPECIAL
WEATHER STATEMENT WILL CONTINUE TO BE USED TO HIGHLIGHT THE SNOW
SQUALL THREAT. CURRENT HIGH-RES DATA SUGGESTS THAT FOR ANY GIVEN
LOCATION...THE THREAT SHOULD BE BRIEF ENOUGH TO LIMIT THE
USEFULNESS OF AN ADVISORY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
ON THURSDAY NIGHT...SURFACE HIGH PRESSURE WILL BEGIN TO BUILD IN
FROM THE WEST. WITH COLD ADVECTION CONTINUING THROUGH FRIDAY
MORNING...TEMPERATURES WILL EASILY DROP INTO THE SINGLE
DIGITS...WITH THE POSSIBILITY FOR SOME VALUES NEAR ZERO IN THE
NORTHERN CWA. ALTHOUGH WINDS WILL BE DECREASING AS THE HIGH MOVES
IN...THERE WILL STILL BE ENOUGH WIND TO LEAD TO WIND CHILLS THAT
APPROACH ADVISORY CRITERIA IN THE NORTH AND NORTHEAST CWA. THIS IS
ENOUGH TO CONTINUE A MENTION IN THE HWO...BUT AS VALUES ONLY GET
INTO THE -4 TO -8 DEGREE RANGE FOR AN HOUR OR TWO IN THE FAR
NORTHEAST (SUCH AS THE STRETCH FROM HARDIN TO LICKING
COUNTIES)...THERE DOES NOT APPEAR TO BE ANY NEED FOR A WIND CHILL
ADVISORY.
THOUGH FRIDAY WILL BE COOL AND DRY...WINDS WILL BE SHIFTING BACK
TO THE SOUTHWEST...AS WEAK WARM ADVECTION IS EXPECTED TO BEGIN.
FROM HERE...IT APPEARS THAT THE ENTIRE WEDNESDAY-THURSDAY FORECAST
CYCLE APPEARS LIKELY TO REPEAT ITSELF AGAIN ON FRIDAY-SATURDAY.
HOWEVER...THE STARTING POINT WILL BE COOLER...LEAVING SNOW AS THE
ONLY PRECIPITATION TYPE IN THE FORECAST THROUGH FRIDAY AND
SATURDAY. THE INITIAL SHOT OF THETA-E ADVECTION ALOFT WILL BRING A
SLIGHT CHANCE FOR SOME FLURRIES ON FRIDAY AFTERNOON AND EVENING.
HOWEVER...APPRECIABLE PRECIPITATION WILL REMAIN WELL NORTH OF THE
FORECAST AREA UNTIL SATURDAY MORNING.
A STRENGTHENING SURFACE LOW IS FORECAST TO MOVE SOUTHEAST THROUGH
THE GREAT LAKES...WITH ANOTHER ARCTIC COLD FRONT PUSHING INTO THE
OHIO VALLEY DURING THE LATE MORNING AND AFTERNOON HOURS. THE TREND
WITH THE STRENGTH OF THIS FRONT AND THE POTENTIAL FOR SNOW APPEARS
TO BE SLIGHTLY UPWARD WITH THE 00Z MODEL RUNS. THE SURFACE LOW
WILL BE QUITE A BIT STRONGER THAN THE THURSDAY LOW...AND IN
ADDITION TO ANOTHER POTENTIAL VORTICITY ANOMALY...UPPER JET
SUPPORT WILL BE STRONGER AS WELL (WITH A 500MB NORTHWESTERLY STREAK
OF OVER 120 KNOTS PUSHING THROUGH NORTHERN ILLINOIS AND INTO
KENTUCKY). BUFKIT SOUNDINGS SUGGEST A LITTLE MORE INSTABILITY THAN
THE THURSDAY EVENT...AND SLIGHTLY STRONGER WIND GUSTS AS
WELL...WITH GOOD AGREEMENT ON THESE PARAMETERS ON RECENT RUNS OF
BOTH THE GFS/NAM (THOUGH THE ECMWF IS SLIGHTLY WEAKER ON THESE
FINER DETAILS...THIS COULD ALSO BE A FUNCTION OF ITS LACK OF
RESOLUTION ON AWIPS). THUS...ANOTHER ROUND OF SNOW IS EXPECTED
SATURDAY (WITH ACCUMULATIONS THAT COULD BE AN INCH OR TWO)...WITH
THE POTENTIAL FOR SNOW SQUALLS AND ALL THE USUAL HAZARDS THEY
BRING.
BY SUNDAY MORNING...FRIGID AIR WILL BE IN PLACE ACROSS THE ENTIRE
CWA...LIKELY ALSO AIDED BY A LITTLE BIT OF SNOW ON THE GROUND.
MIN TEMPS ARE EXPECTED TO RANGE FROM AROUND 5 DEGREES (FAR SOUTH)
TO -5 DEGREES (FAR NORTH). COMBINED WITH NORTHERLY FLOW OF AROUND
10 KNOTS...WIND CHILLS WILL RANGE FROM -5 DEGREES (FAR SOUTH) TO
-25 DEGREES (FAR NORTH). HEADLINES WILL LIKELY BE REQUIRED. RECORD
LOWS FOR SUNDAY (FEBRUARY 15) ARE AS FOLLOWS.
CVG...-1...2007
CMH...-4...1978
DAY...-5...2007
AS COLD ADVECTION IS EXPECTED TO CONTINUE THROUGH THE DAY ON
SUNDAY...THE DIURNAL CURVE WILL BE FAIRLY SMALL...AIDED ONLY BY
SOME SUN AS SKIES BECOME MOSTLY CLEAR. THE MAX TEMP FORECAST
RANGES FROM 5 TO 15 DEGREES. HERE ARE THE RECORD LOW MAXIMUM
TEMPERATURES FOR SUNDAY (FEBRUARY 15).
CVG...13...1920
CMH...12...1920
DAY...11...1920
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE HIGH AXIS CROSSES AND WEAKENS SIGNIFICANTLY EARLY MONDAY AND
SHOULD ALLOW FOR SOME SUN AND WEAKER WINDS FROM A SLIGHTLY LESS
COLD AIRMASS TO SEE READINGS REBOUND INTO THE 20S. FLOW WILL TURN
SOUTHWEST AND LIMIT NIGHTTIME FALLS WITH A WARM PUSH MONDAY NIGHT
AND TUESDAY AHEAD OF THE NEXT COLD FRONTAL PASSAGE.
THE NEXT SYSTEM ON TUESDAY IS BEING PROGGED TO COME FROM THE GULF
STATES AND THE TN VALLEY AND BE WELL AHEAD OF THE POSITIVE TILTED
L/W TROUGH OVER THE CENTRAL U.S. THIS LEADS ME TO NOTE THAT THE
PREVIOUS SYSTEMS PROMISING MUCH SNOW IN THE REGION WERE OF SIMILAR
ORIGIN WITH LITTLE UPPER SUPPORT. CONFIDENCE IN THE FORECAST TANKS
FOR THE LAST DAY OR SO IN THE FORECAST BUT HAS THE POTENTIAL FOR A
WINTER EVENT OVER THE REGION.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A POTENT...BUT FAST MOVING...MID LEVEL TROUGH WILL PUSH THROUGH
THE GREAT LAKES AND OHIO VALLEY TODAY. LARGE SCALE ASCENT AHEAD OF
THIS FEATURE...ALONG WITH INCREASING INSTABILITY...WILL RESULT IN
NUMEROUS SNOW SHOWERS LATER THIS MORNING. IN ADDITION...A FOCUSED
LOW LEVEL BOUNDARY WILL MOVE ACROSS THE TAF SITES. THIS BOUNDARY
WILL MARK AN AREA OF ENHANCED SNOW SHOWERS/SNOW SQUALLS WITH THE
POTENTIAL FOR VISIBILITIES TO DROP BRIEFLY TO A MILE OR LESS. AVIATORS
CAN EXPECT MVFR CEILINGS AND VISIBILITIES IN SNOW SHOWERS THIS
MORNING WITH IFR OR LESS CONDITIONS IN THE HEAVIER SNOW
SHOWERS/SQUALLS. ONCE THE MAIN MID LEVEL TROUGH AXIS MOVES
BY...SNOW SHOWER COVERAGE SHOULD DECREASE MARKEDLY AS LARGE SCALE
SUBSIDENCE TAKES OVER. THIS WILL BRING CEILINGS BACK TO VFR BY THE
AFTERNOON HOURS. AN INCREASING PRESSURE GRADIENT A DEEPER MIXING
TODAY WILL BRING GUSTY NORTHWEST WINDS OF 15 TO 20 KNOTS WITH
GUSTS AROUND 30 KNOTS.
FOR TONIGHT...AN AREA OF HIGH PRESSURE WILL MOVE TOWARD THE
REGION. WINDS WILL GRADUALLY DECREASE THIS EVENING. THERE SHOULD
BE A MIX OF SCATTERED STRATOCUMULUS CLOUDS AND HIGH CLOUDS WITH
VFR CONDITIONS EXPECTED.
OUTLOOK...MVFR CEILINGS AND MVFR/IFR VISIBILITIES POSSIBLE SATURDAY
AND SATURDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...FRANKS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
640 PM EST FRI FEB 13 2015
.SYNOPSIS...
A STRONG ARCTIC FRONT WILL SLICE ACROSS THE COMMONWEALTH FROM THE
LATE SATURDAY MORNING THROUGH SATURDAY AFTERNOON...PRECEDED BY
AREAS OF LIGHT SNOW AND A LINE OF INTENSE SNOW SQUALLS. WIDESPREAD
LIGHT SNOW ACCUMULATIONS ARE EXPECTED FOR MOST...WHILE A FEW TO
SEVERAL INCHES OF WIND BLOWN SNOW ARE POSSIBLE ACROSS THE HIGHER
ELEVATIONS OF THE NORTHERN AND WESTERN MOUNTAINS...AND IN
PARTICULAR THE LAUREL HIGHLANDS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
MCLEAR SKIES AND LIGHT WINDS TO START THIS EVENING...AS SFC RIDGE
DRIFTS ACROSS CENTRAL PA. HOWEVER...SATL LOOP SHOWS CLOUDS IN
ADVANCE OF APPROACHING CLIPPER ABOUT TO ENTER WESTERN PA AT 22Z.
IDEAL RADIATIONAL COOLING SHOULD RESULT IN MIN TEMPS THIS
EVENING...THEN STEADY OR SLOWLY RISING READINGS AS CLOUDS ARRIVE
BTWN 00Z-05Z FROM WEST TO EAST. CONSALL OUTPUT SUGGEST LOWS WILL
RANGE FROM THE UPPER SINGLE DIGITS TO LTEENS OVER MOST OF THE
AREA. HOWEVER...LATEST RAP OUTPUT SUGGESTS THE COLDER VALLEYS OF
THE NORTH WILL DIP BLW ZERO FOR A TIME THIS EVENING...WITH SOME
SINGLE DIGITS IN THE FROST POCKETS OF THE CENTRAL AND SOUTHERN
COUNTIES.
REGIONAL RADAR LOOP AT 22Z SHOWS LIGHT SNOW ACROSS MICHIGAN IN
REGION OF WAA AHEAD OF CLIPPER. LATEST NR TERM MDL DATA SUGGESTS
THIS LGT SNOW WILL OVERSPREAD THE N MTNS BTWN 03Z-06Z. LACK OF
DEEP MOISTURE WILL LIMIT LGT ACCUMS TO MAINLY THE N MTNS...WHERE
SOUTHERLY FLOW/OROGRAPHIC LIFT WILL PLAY A ROLE. BLEND OF MDL QPF
SUPPORTS SNOW AMTS BY DAWN OF NEAR AN INCH ACROSS THE N MTNS...WITH
LITTLE IF ANY ACCUM SOUTH OF I-80.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
A VIGOROUS UPPER TROUGH AND ASSOCIATED ARCTIC FRONT WILL
DROP SOUTHEAST THROUGH THE REGION DURING THE DAY SATURDAY.
BROAD UPPER DIFFLUENCE AHEAD OF THIS TROUGH AND A BRIEF PERIOD OF
SWRLY FLOW AT THE SURFACE WILL MAINTAIN LIGHT SNOW/SNOW SHOWERS
ACROSS WESTERN AND CENTRAL AREAS THROUGH THE MORNING HOURS.
AN APPROX 75NM WIDE BAND OF STEEP MID-LEVEL LAPSE RATES /OR 7-8C
PER KM/ OCCURS ALONG AND JUST IN ADVANCE OF THE ARCTIC FRONT
SATURDAY. THIS WILL LEAD TO SCATTERED...BLINDING SNOW SQUALLS
GIVEN THE STRONG 40-45 KT WINDS AT 850 MB SURROUNDING THE CFROPA.
BTV SNOW SQUALL PARAMETER AND HI RES MESO MODELS ARE HITTING ON
ALL CYLINDERS WITH THIS SQUALL EVENT...AND IT IS CLEAR THAT THE
ARCTIC AIR WILL HAVE A LOUD ARRIVAL PUNCTUATED BY A LINE OF
INTENSE SNOW SQUALLS WITH HAZARDOUS INTERSTATE TRAVEL CONDITIONS
EXPECTED FROM WEST TO EAST SATURDAY AFTERNOON.
FAVORABLE UPSLOPE LOCATIONS NEAR AND TO THE WEST OF RT 219 SEE A
GENERAL 2-4 INCHES...WITH ANOTHER INCH OR SO POSSIBLE FROM THE
LINE OF SQUALLS LEADING TO A GENERAL 3 TO 5 INCHES AND GARNERING
THE ISSUANCE OF A WINTER WEATHER ADVISORY FOR SOMERSET CAMBRIA AND
CLEARFIELD COUNTIES. FARTHER NORTH...SIMILAR 2-3 INCH AMOUNTS
LIKELY ACROSS THE MTNS NE OF KIPT AS THE CENTER OF THE 700-500 MB
LOW MOVES NEAR OR JUST SOUTH OF THE REGION LATE SAT NIGHT.
WIND CHILL WATCH FOR SAT EVENING THROUGH SUNDAY MORNING FOR THE
ENTIRE CWA REMAINS IN EFFECT. HIGH WIND WATCH FOR THE LOWER SUSQ
RIVER VALLEY ALSO REMAINS IN EFFECT.
HIGHS SATURDAY WILL NOSE INTO THE LOWER 20S LATE IN THE MORNING
ACROSS THE NW MTNS AND LAURELS...AND INTO THE LOWER 30S ACROSS THE
SE ZONES EARLY SATURDAY AFTERNOON - BEFORE THE ARCTIC FRONT SURGES
SE ACROSS THE REGION.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT
LEAST THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES
TO DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
NEXT STORM WILL BE EXITING THE REGION SAT NIGHT /AND WILL BE
DEEPENING RAPIDLY AS IT IMPACTS THE NEW ENGLAND COAST/...WITH
SNOW SHOWERS LINGERING MAINLY IN MY HIGHER TERRAIN INTO SUNDAY.
SOME DEFORMATION SNOWFALL IS POSSIBLE OVER EASTERN PORTIONS OF
MY CWA EARLY SUNDAY...AND HAVE KEPT ELEVATED POPS AND LIGHT
ACCUMULATIONS OF UP TO A FEW INCHES IN FOR THAT LIKELIHOOD.
BIGGER STORM WILL BE SURGE OF BRUTALLY COLD AIR IN ITS
WAKE...BRINGING THE COLDEST AIR OF THE SEASON TO PA. THE COLDEST
TEMPS /AND WIND CHILLS/ ARRIVE SAT NIGHT AND CONTINUE INTO
SUNDAY...WITH COLDEST STRAIGHT- UP TEMP READINGS SUN NIGHT WHEN
GEFS MEAN 850 MB TEMPS DROP TO -24 TO -28C ACROSS CENTRAL PENN.
AFTERNOON HIGHS SUNDAY WILL REMAIN BELOW ZERO ACROSS THE NORTHERN
MOUNTAINS AND LAUREL HIGHLANDS...AND MAINLY IN THE SINGLE DIGITS
ABOVE ZERO ELSEWHERE. TO COMPLICATE MATTERS...STRONG NORTHWEST
WIND GUSTS ANTICIPATED OVER 40 MPH SAT NIGHT AND EARLY SUNDAY
WILL BRING ANOTHER ROUND OF DANGEROUS...AND EVEN COLDER WIND
CHILLS OF 20 TO 30 BELOW ZERO. THOUGH WINDS WILL GRADUALLY RELAX
INTO MON...COMBINATION OF COLD TEMPS AND WIND JUSTIFIES THE WIND
CHILL WATCH CURRENTLY IN EFFECT THROUGH THAT 36HR PERIOD. THIS
WILL LIKELY NEED TO BE UPGRADED TO A WARNING AS EVENT WINDOW
APPROACHES. WILL ALSO NEED TO STRONGLY CONSIDER A WIND ADVISORY
ESP FOR HIGHER TERRAIN AND NW-SE ALIGNED VALLEYS ACROSS SOUTHERN
AREAS SAT NIGHT INTO EARLY SUN WITH PEAK WIND GUSTS IN THE 40-50
MPH RANGE.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS
CONTINUE TO LEND CREEDENCE TOWARD A MORE SUPPRESSED/FLATTER
SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT
LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM
PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EARLY TONIGHT.
MVFR AND IFR CONDITIONS LATE TONIGHT INTO SAT...WITH FAST
MOVING CLIPPER LOW DROPPING SE.
ADDED TEMPO GROUP TO ALL SITES WITH COLD FRONT...HIGHER
CHNANCE FOR A SQUALL ALONG COLD FRONT AND GUSTY WINDS THAN
WITH THE SITUATION YESTERDAY (THU)...GIVEN STRONG DYNAMICS.
STRONG WINDS EXPECTED LATE SAT INTO SUNDAY...AS LOW REFORMS
OFF THE COAST.
FLOW NOT REAL GOOD FOR LAKE EFFECT SNOW SHOWERS...AND ICE COVER
ON THE LAKES IS ON INCREASE...ALONG WITH THE NORTHERLY FLOW WILL
LIMIT SNOW SHOWERS. HOWEVER...TRACK OF THE UPPER LEVEL LOW WILL
KEEP SOME CHANCE OF SNOW SHOWERS ACROSS THE AREA INTO SUNDAY
MORNING...ESPECIALLY ACROSS NE PA.
VERY COLD TEMPS LATE SATURDAY INTO MONDAY.
IMPROVING CONDITIONS FOR MONDAY...AS HIGH PRESSURE BUILDS
INTO THE AREA AND WINDS WEAKEN SOME.
MORE SNOW POSSIBLE LATER TUE INTO WED...AS SYSTEMS MOVE
TO THE NORTH AND SOUTH OF PA. MODELS HOLD OFF PHASING THESE UNTIL
THE NEW LOW IS WELL OFF THE COAST. STILL IT WILL BECOME WINDY AND
COLDER AGAIN.
OUTLOOK...
SAT...BCMG MVFR/IFR IN -SN. STG FROPA. WNW SFC WND GUSTS 25-35KTS.
SUN...MVFR/IFR WEST IN -SHSN. VFR/MVFR CENTRAL AND EAST. WNW SFC
WND GUSTS 25-35KTS.
MON...MVFR -SHSN EARLY WEST...BCMG VFR. VFR ELSEWHERE.
TUE...CHC OF PM SNOW.
WED...CHC OF AM SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR PAZ012-018-019-025>028-034>037-041-042-045-046-
049>053-056>059-063>066.
WINTER WEATHER ADVISORY FROM 7 AM SATURDAY TO MIDNIGHT EST
SUNDAY NIGHT FOR PAZ017-024-033.
WIND CHILL WATCH FROM SATURDAY EVENING THROUGH MONDAY MORNING
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...DEVOIR/LAMBERT
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...DEVOIR/LAMBERT
LONG TERM...RXR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
454 PM EST THU FEB 12 2015
.SYNOPSIS...
AN ARCTIC FRONT WILL BRING SNOW SHOWERS AND A FEW SQUALLS TO
CENTRAL PENNSYLVANIA TODAY FOLLOWED BY FRIGID TEMPERATURES TONIGHT
INTO EARLY FRIDAY. ANOTHER ARCTIC BLAST IS EXPECTED THIS WEEKEND
ALONG WITH ACCUMULATING SNOW FOR MOST OF THE AREA.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE AREA OF CONVECTIVE SNOW HAS ENDED AND THE MAIN ARCTIC COLD
FRONT WILL PUSH NW TO SE THRU CENTRAL PA THROUGH THIS EVE. UPSLOPE
FLOW WILL CONTINUE ACROSS THE LAURELS...HOWEVER LATEST HRRR SHOWS
DECREASED SNOW FALL...WITH ONLY LIGHT ACCUMULATIONS POSSIBLE INTO
FRIDAY MORNING.
THE ADVECTION OF COLD ARCTIC AIR AND INCREASING WNW WINDS WITH
FREQUENT GUSTS BETWEEN 25-40MPH ON THE BACKSIDE OF DEEPENING
OFFSHORE LOW WILL CREATE FRIGID WIND CHILLS ACROSS THE AREA
TONIGHT INTO EARLY FRIDAY. WIND CHILL WARNING FOR THE NORTHERN
TIER REMAINS WITH EXTREMELY DANGEROUS READINGS IN THE -25 TO -35
BELOW ZERO RANGE. EXPANDED THE WIND CHILL ADVISORY TO INCLUDE THE
REST OF THE COUNTIES BASED ON DROPPING MODEL TEMPS AND INCREASE
GRADIENT WHICH SHOULD ALLOW WINDS TO REMAIN SUSTAINED INTO THE
OVERNIGHT PERIOD WITH WIND CHILLS DROPPING TO 15 BELOW ZERO.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE RIDGE WILL BUILD INTO THE REGION FRIDAY...BRINGING
SLOWLY DECREASING NW WINDS AND PARTLY TO MOSTLY SUNNY SKIES ACROSS
THE CENTRAL AND SE ZONES. THE NW MTNS MAY HAVE A TOUGH TIME BREAKING
UP THE SHALLOW STRATO CU AND SCT FLURRIES.
FRIDAY WILL LIKELY BE ONE OF THE COLDEST DAYS OF THE WINTER SEASON
SO FAR WITH ANOMALOUSLY LOW GEFS MEAN 925 MB TEMPS OF ARND
-18C LIKELY SUPPORTING HIGH TEMPS NO BETTER THAN THE SINGLE
DIGITS ACROSS THE NORTHERN MTNS...TO THE UPPER TEENS ACROSS THE
SOUTHERN VALLEYS.
ANOTHER TROUGH IS EXPECTED TO DROP DOWN THROUGH THE REGION EARLY
SATURDAY MORNING. THIS SYSTEM HAS A DEEPER TROUGH WITH WINDS OUT
OF THE SOUTHWEST. WITH A DECENT SHORTWAVE...AND STRONG LLJ THERE
IS A GOOD CHANCE FOR ANOTHER ROUND OF SNOW SQUALLS SATURDAY INTO
SATURDAY NIGHT. EVEN COLDER AIR LOOKS TO ADVECT INTO THE REGION
SATURDAY NIGHT INTO SUNDAY...WITH THE WINDS PERSISTING INTO THE
EVENING HOURS. GOOD CONFIDENCE IN LOW WIND CHILLS SATURDAY
EVENING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
LONG TERM WILL BE PUNCTUATED BY BRUTALLY COLD AIRMASS TO BEGIN THE
PERIOD...WITH FRIGID WIND CHILLS AND MINI MAX RECORDS LIKELY
ACROSS MUCH OF CENTRAL PA ON SUNDAY. STRONG CLIPPER DROPS ACROSS
THE EASTERN GLAKS SAT NIGHT AND DEEPENS RAPIDLY OVER LONG ISLAND
AND ALONG THE SOUTHERN NEW ENGLAND COAST...LIKELY THROWING
ACCUMULATING SNOW OVER THE POCONO PLATEAU THROUGH SUNDAY MORNING.
SOME DEFORMATION SNOWFALL IS POSSIBLE OVER EASTERN PORTIONS OF MY
CWA ON SUNDAY...AND HAVE KEPT ELEVATED POPS AND LIGHTER
ACCUMULATIONS IN FOR THAT LIKELIHOOD.
THE DEEP CHILL WILL PERSIST ON MONDAY AS A SUCCESSION OF NORTHERN
STREAM WAVES DROPS WELL SOUTH OF THE REGION THROUGH THE CENTRAL
AND SOUTHERN PLAINS. SURFACE HIGH WILL PROPOGATE ACROSS CENTRAL PA
MONDAY AND MONDAY NIGHT...MOVING OFFSHORE ON TUESDAY. MODEL
GUIDANCE AND EFS INDICATE PHASING OF NORTHERN AND SOUTHERN STREAM
WAVES OVER THE GULF COAST AND SOUTHEASTERN U.S. BY LATER TUE INTO
WEDNESDAY...BRINGING THE CHANCE OF SNOW TO THE REGION. COLD
NORTHWEST FLOW RESUMES FOR THE REMAINDER OF NEXT WEEK AS A MASSIVE
RIDGE OF HIGH PRESSURE COVERS THE EASTERN HALF OF THE CONUS LATER
WED-FRI.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
21Z TAFS SENT.
GUSTY WINDS INTO TONIGHT.
MOST AREAS VFR BUT MVFR AND EVEN IFR AT TIMES AT JST AND BFD
INTO FRIDAY MORNING.
OUTLOOK...
SAT...BCMG MVFR/IFR WITH -SN. FROPA FOLLOWED BY GUSTY WNW WINDS.
SUN...MVFR/IFR WEST IN -SHSN. STRONG GUSTY WNW WINDS.
MON...MVFR/IFR WITH -SHSN EARLY...THEN VFR.
TUE...MVFR/IFR WITH -SN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR PAZ004>006-037-
042.
WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR PAZ010>012-
017>019-024>028-033>036-041-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR PAZ033.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...FITZGERALD/CERU
SHORT TERM...FITZGERALD/CERU
LONG TERM...DEVOIR/FITZGERALD
AVIATION...DEVOIR/CERU/MARTIN/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
325 PM EST THU FEB 12 2015
.SYNOPSIS...
AN ARCTIC FRONT WILL BRING SNOW SHOWERS AND A FEW SQUALLS TO
CENTRAL PENNSYLVANIA TODAY FOLLOWED BY FRIGID TEMPERATURES TONIGHT
INTO EARLY FRIDAY. ANOTHER ARCTIC BLAST IS EXPECTED THIS WEEKEND
ALONG WITH ACCUMULATING SNOW FOR MOST OF THE AREA.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE AREA OF CONVECTIVE SNOW HAS ENDED AND THE MAIN ARCTIC COLD
FRONT WILL PUSH NW TO SE THRU CENTRAL PA THROUGH THIS EVE. UPSLOPE
FLOW WILL CONTINUE ACROSS THE LAURELS...HOWEVER LATEST HRRR SHOWS
DECREASED SNOW FALL...WITH ONLY LIGHT ACCUMULATIONS POSSIBLE INTO
FRIDAY MORNING.
THE ADVECTION OF COLD ARCTIC AIR AND INCREASING WNW WINDS WITH
FREQUENT GUSTS BETWEEN 25-40MPH ON THE BACKSIDE OF DEEPENING
OFFSHORE LOW WILL CREATE FRIGID WIND CHILLS ACROSS THE AREA
TONIGHT INTO EARLY FRIDAY. WIND CHILL WARNING FOR THE NORTHERN
TIER REMAINS WITH EXTREMELY DANGEROUS READINGS IN THE -25 TO -35
BELOW ZERO RANGE. EXPANDED THE WIND CHILL ADVISORY TO INCLUDE THE
REST OF THE COUNTIES BASED ON DROPPING MODEL TEMPS AND INCREASE
GRADIENT WHICH SHOULD ALLOW WINDS TO REMAIN SUSTAINED INTO THE
OVERNIGHT PERIOD WITH WIND CHILLS DROPPING TO 15 BELOW ZERO.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE RIDGE WILL BUILD INTO THE REGION FRIDAY...BRINGING
SLOWLY DECREASING NW WINDS AND PARTLY TO MOSTLY SUNNY SKIES ACROSS
THE CENTRAL AND SE ZONES. THE NW MTNS MAY HAVE A TOUGH TIME BREAKING
UP THE SHALLOW STRATO CU AND SCT FLURRIES.
FRIDAY WILL LIKELY BE ONE OF THE COLDEST DAYS OF THE WINTER SEASON
SO FAR WITH ANOMALOUSLY LOW GEFS MEAN 925 MB TEMPS OF ARND
-18C LIKELY SUPPORTING HIGH TEMPS NO BETTER THAN THE SINGLE
DIGITS ACROSS THE NORTHERN MTNS...TO THE UPPER TEENS ACROSS THE
SOUTHERN VALLEYS.
ANOTHER TROUGH IS EXPECTED TO DROP DOWN THROUGH THE REGION EARLY
SATURDAY MORNING. THIS SYSTEM HAS A DEEPER TROUGH WITH WINDS OUT
OF THE SOUTHWEST. WITH A DECENT SHORTWAVE...AND STRONG LLJ THERE
IS A GOOD CHANCE FOR ANOTHER ROUND OF SNOW SQUALLS SATURDAY INTO
SATURDAY NIGHT. EVEN COLDER AIR LOOKS TO ADVECT INTO THE REGION
SATURDAY NIGHT INTO SUNDAY...WITH THE WINDS PERSISTING INTO THE
EVENING HOURS. GOOD CONFIDENCE IN LOW WIND CHILLS SATURDAY
EVENING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
LONG TERM WILL BE PUNCTUATED BY BRUTALLY COLD AIRMASS TO BEGIN THE
PERIOD...WITH FRIGID WIND CHILLS AND MINI MAX RECORDS LIKELY
ACROSS MUCH OF CENTRAL PA ON SUNDAY. STRONG CLIPPER DROPS ACROSS
THE EASTERN GLAKS SAT NIGHT AND DEEPENS RAPIDLY OVER LONG ISLAND
AND ALONG THE SOUTHERN NEW ENGLAND COAST...LIKELY THROWING
ACCUMULATING SNOW OVER THE POCONO PLATEAU THROUGH SUNDAY MORNING.
SOME DEFORMATION SNOWFALL IS POSSIBLE OVER EASTERN PORTIONS OF MY
CWA ON SUNDAY...AND HAVE KEPT ELEVATED POPS AND LIGHTER
ACCUMULATIONS IN FOR THAT LIKELIHOOD.
THE DEEP CHILL WILL PERSIST ON MONDAY AS A SUCCESSION OF NORTHERN
STREAM WAVES DROPS WELL SOUTH OF THE REGION THROUGH THE CENTRAL
AND SOUTHERN PLAINS. SURFACE HIGH WILL PROPOGATE ACROSS CENTRAL PA
MONDAY AND MONDAY NIGHT...MOVING OFFSHORE ON TUESDAY. MODEL
GUIDANCE AND EFS INDICATE PHASING OF NORTHERN AND SOUTHERN STREAM
WAVES OVER THE GULF COAST AND SOUTHEASTERN U.S. BY LATER TUE INTO
WEDNESDAY...BRINGING THE CHANCE OF SNOW TO THE REGION. COLD
NORTHWEST FLOW RESUMES FOR THE REMAINDER OF NEXT WEEK AS A MASSIVE
RIDGE OF HIGH PRESSURE COVERS THE EASTERN HALF OF THE CONUS LATER
WED-FRI.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
INCREASINGLY COLD/BLUSTERY WNW FLOW IN WAKE OF ARCTIC FRONT
THROUGHOUT CENTRAL PA. SFC WINDS 290-320 AND INCREASING INTO
TONIGHT WITH GUSTS 25-35KTS. CONDS SHOULD IMPROVE EAST OF THE MTNS
OVERNIGHT WITH CIG RESTRICTIONS LKLY PERSISTING AT BFD/JST INTO
FRIDAY MORNING.
OUTLOOK...
FRI...MVFR/IFR WITH -SHSN WEST EARLY...THEN GRADUALLY IMPROVING.
SAT...BCMG MVFR/IFR WITH -SN. FROPA FOLLOWED BY GUSTY WNW WINDS.
SUN...MVFR/IFR WEST IN -SHSN. STRONG GUSTY WNW WINDS.
MON...MVFR/IFR WITH -SHSN EARLY...THEN VFR LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM 7 PM THIS EVENING TO NOON EST FRIDAY
FOR PAZ004>006-037-042.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO NOON EST FRIDAY
FOR PAZ010>012-017>019-024>028-033>036-041-045-046-049>053-
056>059-063>066.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR PAZ033.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...FITZGERALD/CERU
SHORT TERM...FITZGERALD/CERU
LONG TERM...DEVOIR/FITZGERALD
AVIATION...DEVOIR/CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
314 PM EST THU FEB 12 2015
.SYNOPSIS...
AN ARCTIC FRONT WILL BRING SNOW SHOWERS AND A FEW SQUALLS TO
CENTRAL PENNSYLVANIA TODAY FOLLOWED BY FRIGID TEMPERATURES TONIGHT
INTO EARLY FRIDAY. ANOTHER ARCTIC BLAST IS EXPECTED THIS WEEKEND
ALONG WITH ACCUMULATING SNOW FOR MOST OF THE AREA.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE AREA OF CONVECTIVE SNOW HAS ENDED AND THE MAIN ARCTIC COLD
FRONT WILL PUSH NW TO SE THRU CENTRAL PA THROUGH THIS EVE. UPSLOPE
FLOW WILL CONTINUE ACROSS THE LAURELS...HOWEVER LATEST HRRR SHOWS
DECREASED SNOW FALL...WITH ONLY LIGHT ACCUMULATIONS POSSIBLE INTO
FRIDAY MORNING.
THE ADVECTION OF COLD ARCTIC AIR AND INCREASING WNW WINDS WITH
FREQUENT GUSTS BETWEEN 25-40MPH ON THE BACKSIDE OF DEEPENING
OFFSHORE LOW WILL CREATE FRIGID WIND CHILLS ACROSS THE AREA
TONIGHT INTO EARLY FRIDAY. WIND CHILL WARNING FOR THE NORTHERN
TIER REMAINS WITH EXTREMELY DANGEROUS READINGS IN THE -25 TO -35
BELOW ZERO RANGE. EXPANDED THE WIND CHILL ADVISORY TO INCLUDE THE
REST OF THE COUNTIES BASED ON DROPPING MODEL TEMPS AND INCREASE
GRADIENT WHICH SHOULD ALLOW WINDS TO REMAIN SUSTAINED INTO THE
OVERNIGHT PERIOD WITH WIND CHILLS DROPPING TO 15 BELOW ZERO.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE RIDGE WILL BUILD INTO THE REGION FRIDAY...BRINGING
SLOWLY DECREASING NW WINDS AND PARTLY TO MOSTLY SUNNY SKIES ACROSS
THE CENTRAL AND SE ZONES. THE NW MTNS MAY HAVE A TOUGH TIME BREAKING
UP THE SHALLOW STRATO CU AND SCT FLURRIES.
FRIDAY WILL LIKELY BE ONE OF THE COLDEST DAYS OF THE WINTER SEASON
SO FAR WITH ANOMALOUSLY LOW GEFS MEAN 925 MB TEMPS OF ARND
-18C LIKELY SUPPORTING HIGH TEMPS NO BETTER THAN THE SINGLE
DIGITS ACROSS THE NORTHERN MTNS...TO THE UPPER TEENS ACROSS THE
SOUTHERN VALLEYS.
ANOTHER TROUGH IS EXPECTED TO DROP DOWN THROUGH THE REGION EARLY
SATURDAY MORNING. THIS SYSTEM HAS A DEEPER TROUGH WITH WINDS OUT
OF THE SOUTHWEST. WITH A DECENT SHORTWAVE...AND STRONG LLJ THERE
IS A GOOD CHANCE FOR ANOTHER ROUND OF SNOW SQUALLS SATURDAY INTO
SATURDAY NIGHT. EVEN COLDER AIR LOOKS TO ADVECT INTO THE REGION
SATURDAY NIGHT INTO SUNDAY...WITH THE WINDS PERSISTING INTO THE
EVENING HOURS. GOOD CONFIDENCE IN LOW WIND CHILLS SATURDAY
EVENING.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
LONG TERM WILL BE PUNCTUATED BY BRUTALLY COLD AIRMASS TO BEGIN THE
PERIOD...WITH FRIGID WIND CHILLS AND MINI MAX RECORDS LIKELY
ACROSS MUCH OF CENTRAL PA ON SUNDAY. STRONG CLIPPER DROPS ACROSS
THE EASTERN GLAKS SAT NIGHT AND DEEPENS RAPIDLY OVER LONG ISLAND
AND ALONG THE SOUTHERN NEW ENGLAND COAST...LIKELY THROWING
ACCUMULATING SNOW OVER THE POCONO PLATEAU THROUGH SUNDAY MORNING.
SOME DEFORMATION SNOWFALL IS POSSIBLE OVER EASTERN PORTIONS OF MY
CWA ON SUNDAY...AND HAVE KEPT ELEVATED POPS AND LIGHTER
ACCUMULATIONS IN FOR THAT LIKELIHOOD.
THE DEEP CHILL WILL PERSIST ON MONDAY AS A SUCCESSION OF NORTHERN
STREAM WAVES DROPS WELL SOUTH OF THE REGION THROUGH THE CENTRAL
AND SOUTHERN PLAINS. SURFACE HIGH WILL PROPOGATE ACROSS CENTRAL PA
MONDAY AND MONDAY NIGHT...MOVING OFFSHORE ON TUESDAY. MODEL
GUIDANCE AND EFS INDICATE PHASING OF NORTHERN AND SOUTHERN STREAM
WAVES OVER THE GULF COAST AND SOUTHEASTERN U.S. BY LATER TUE INTO
WEDNESDAY...BRINGING THE CHANCE OF SNOW TO THE REGION. COLD
NORTHWEST FLOW RESUMES FOR THE REMAINDER OF NEXT WEEK AS A MASSIVE
RIDGE OF HIGH PRESSURE COVERS THE EASTERN HALF OF THE CONUS LATER
WED-FRI.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
INCREASINGLY COLD/BLUSTERY WNW FLOW IN WAKE OF ARCTIC FRONT
THROUGHOUT CENTRAL PA. SFC WINDS 290-320 AND INCREASING INTO
TONIGHT WITH GUSTS 25-35KTS. CONDS SHOULD IMPROVE EAST OF THE MTNS
OVERNIGHT WITH CIG RESTRICTIONS LKLY PERSISTING AT BFD/JST INTO
FRIDAY MORNING.
OUTLOOK...
FRI...MVFR/IFR WITH -SHSN WEST EARLY...THEN GRADUALLY IMPROVING.
SAT...BCMG MVFR/IFR WITH -SN. FROPA FOLLOWED BY GUSTY WNW WINDS.
SUN...MVFR/IFR WEST IN -SHSN. STRONG GUSTY WNW WINDS.
MON...MVFR/IFR WITH -SHSN EARLY...THEN VFR LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM 7 PM THIS EVENING TO NOON EST FRIDAY
FOR PAZ004>006-037-042.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO NOON EST FRIDAY
FOR PAZ010>012-017>019-024>028-033>036-041-045-046-049>053-058.
WINTER WEATHER ADVISORY UNTIL 1 AM EST FRIDAY FOR PAZ033.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...FITZGERALD/CERU
SHORT TERM...FITZGERALD/CERU
LONG TERM...DEVOIR/FITZGERALD
AVIATION...DEVOIR/CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
111 AM EST THU FEB 12 2015
.SYNOPSIS...
ARCTIC AIR WILL PUSH INTO THE COMMONWEALTH OVERNIGHT AND
THURSDAY. SNOW SHOWERS AND SNOW SQUALLS WILL CROSS CENTRAL
PENNSYLVANIA THURSDAY MORNING AND AFTERNOON BEFORE BITTERLY COLD
AIR ARRIVES AND DANGEROUSLY LOW WIND CHILLS OCCUR THURSDAY NIGHT
AND FRIDAY. ANOTHER POTENT UPPER LEVEL SHORTWAVE AND ASSOCIATED
CLIPPER WILL DELIVER AN EVEN COLDER SHOT OF ARCTIC AIR TO THE
REGION ON SUNDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
WATER VAPOR LOOP SHOWS POTENT SHORTWAVE DIVING SE ACROSS
WISCONSIN AT 0530Z. LG SCALE FORCING AHEAD OF THIS FEATURE IS
SUPPORTING SOME LIGHT SNOW FROM WESTERN NY STATE SW INTO OHIO.
ARCTIC COLD FRONT AT 05Z LIES ACROSS S ONTARIO INTO S MICHIGAN. AS
SHORTWAVE PRESSES EAST...EXPECT PERIODS OF LGT SNOW TO FALL OVR
THE ALLEGHENY PLATEAU EARLY THIS MORNING. UPSTREAM REPORTS ACROSS
SE OHIO/SW PA INDICATE SOME FZDZ...WHERE CLOUD TOP TEMPS REMAIN
RELATIVELY WARM. LATEST RAP OUTPUT INDICATES CLOUD TOP TEMPS AOA
-10C COULD SUPPORT A BIT OF FZDZ ACROSS THE LAUREL HIGHLANDS UNTIL
DEEPER/COLDER CLOUD TOPS ARRIVE ARND 08Z-09Z. SOME BRIEFLY HEAVIER
SNOW SHOWERS/SQUALLS COULD AFFECT PARTS OF THE NW MTNS ARND
DAWN...AS ARCTIC COLD FRONT ARRIVES.
LATEST NEAR TERM MDL OUTPUT CONTINUES TO INDICATE ONLY LIGHT
SNOW ACCUMS TONIGHT ACROSS THE ALLEGHENY PLATEAU. BLEND OF EARLIER MDL
QPF AND LATEST HRRR SUGGEST ACCUMS WILL GENERALLY BE LESS THAN AN
INCH ACROSS THE ALLEGHENY PLATEAU...WITH NO MORE THAN A DUSTING
LIKELY ELSEWHERE. CLOUD COVER AND SWRLY FLOW AHEAD OF APPROACHING ARCTIC
COLD FRONT SHOULD RESULT IN A RELATIVELY MILD NIGHT...WITH MIN
TEMPS MOSTLY IN THE 20S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
QPF VERY LIGHT AND UPSLOPE FETCH/FEED NOT ENTIRELY FAVORABLE FOR
SOMERSET COUNTY TO REALLY GET HAMMERED WITH HEAVY SNOW THIS
PERIOD. WILL TAKE THE WATCH AND CONVERT IT TO AN ADVY AND KEEP
MENTIONS OF BLSN...AS WINDS WILL BE PRETTY NASTY. ACCUMS WILL BE
TOUGH TO MEASURE ANYWAY...BUT QPF SO LIGHT - ON THE ORDER OF A
TENTH OF AN INCH - THAT ACCUMS MORE THAN 5 INCHES EVEN ON THE
RIDGES IS UNLIKELY.
WILL KEEP THINKING ABOUT THE WIND CHILL WATCH...IT LOOKS LIKE A
SOLID WARNING IN THE NORTH...BUT AN ADVY WILL BE NECESSARY
ELSEWHERE...BUT HOW FAR SE TO GO WITH IT IS A QUESTION. NO NEED TO
ACT RIGHT AWAY...AND WILL HOLD ONTO THE WIND CHILL WATCH FOR THE
TIME BEING.
PREV...
ARCTIC COLD FRONT WILL SWEEP THRU MOST OF CENTRAL PA BTWN 12Z-18Z
THU BASED ON 12Z GUIDANCE AND BTV SNSQ PARAMETER. SENT I80 EMAIL
NOTIFICATION FOR LINE OF SQUALLS EXPECTED TO CROSS CENTRAL PA THU
MORNING INTO THU AFTERNOON. STEEP LOWER TROPOSPHERIC LAPSE
RATES...COMBINED WITH STRONG LG SCALE FORCING AHEAD OF MID LVL
SHORTWAVE...WILL GENERATE LOCALLY HEAVY SNOW SHOWERS AND SQUALLS
EVEN INTO THE SUSQ VALLEY. ACCUMS THURSDAY SHOULD BE GENERALLY
LESS THAN AN INCH...BUT COULD POTENTIALLY CREATE FLASH FREEZE
CONCERNS OVR THE LOWER SUSQ VALLEY...WHERE ABV FREEZING TEMPS AND
INITIAL MELTING OF SNOW ON ROADS IS POSSIBLE.
OTHER CONCERN IS FOR STRONG UPSLOPE INTO THE LAUREL HIGHLANDS TO
PRODUCE SEVERAL INCHES OF SNOWFALL OVER SOMERSET COUNTY. NW
WINDS INCREASING TO 10-18 KTS WITH GUSTS OCNLY TO 25-30 KTS IN THE
AFTERNOON WILL USHER IN BITTERLY COLD TEMPS AND WIND CHILLS. THE
STRONGEST WINDS WILL LIKELY NOT DEVELOP UNTIL THURSDAY EVENING...AS
PRES GRADIENT TIGHTENS WEST OF RAPIDLY DEVELOPING COASTAL STORM
SOUTH OF CAPE COD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CURRENT ENSEMBLES AND MODEL SOUNDINGS GIVE FURTHER CREDENCE AND
SUPPORT FOR FREQUENT GUSTS TO ARND 35KTS ACROSS MUCH OF CENTRAL
PA BTWN 00Z- 06Z FRIDAY. GUSTY WINDS WILL CONTINUE THROUGH FRIDAY
MORNING. THE STRONG WINDS IN CONJUNCTION W/ARRIVAL OF ARCTIC AIR
MASS WILL LIKELY RESULT WIDESPREAD WIND CHILLS THU NIGHT BTWN
10-20 BLW ZERO. ACROSS THE N MTNS...APPARENT TEMPS IN THE 25-30BLW
RANGE ARE POSSIBLE. CONFIDENCE IN TEMPERATURES AND HAVE THEREFORE
ISSUED A WIND CHILL WATCH UP THERE AND WILL CONTINUE TO MENTION
POSSIBILITY OF DANGEROUS WCHILLS ACROSS THE CENTRAL COUNTIES.
MOSTLY FROZEN LAKES AND DRYNESS OF ARCTIC AIR MASS SHOULD PRECLUDE
ANYTHING MORE THAN SCT -SHSN OVR THE W MTNS THU NIGHT WITH ANY
ADDITIONAL ACCUMS LESS THAN AN INCH.
FRIDAY WILL LIKELY BE ONE OF THE COLDEST DAYS OF THE WINTER
SEASON SO FAR WITH ANOMALOUSLY LOW GEFS MEAN 925 MB TEMPS OF ARND
-18C LIKELY SUPPORTING HIGH TEMPS NO BETTER THAN THE SINGLE
DIGITS ACROSS THE NORTHERN MTNS...TO THE UPPER TEENS ACROSS THE
SOUTHERN VALLEYS.
AN EXTENSIVE RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION FRIDAY
INTO EARLY FRIDAY NIGHT WITH SLOWLY DECREASING NW WINDS AND PARTLY
TO MOSTLY SUNNY SKIES ACROSS THE CENTRAL AND SE ZONES. THE NW MTNS
MAY HAVE A TOUGH TIME BREAKING UP THE SHALLOW STRATO CU WITH A
CHANCE FOR FLURRIES FRIDAY NIGHT INTO SATURDAY.
THE CLIPPER WILL TRACK ACROSS THE CWA LATE FRIDAY NIGHT INTO
SATURDAY...ACCOMPANIED BY NUMEROUS SNOW SHOWERS INTO SATURDAY
DAYTIME...AND PERIODS OF STEADY SNOW INTO SATURDAY EVENING. MODELS
DIFFER ON THE PLACEMENT OF THE UPPER LEVEL LOW...AND AS SUCH THERE
IS SOME VARIANCE ON THE AMOUNT OF QPF AND CORRESPONDING SNOW
AMOUNTS WITH THIS SYSTEM. THE EC MODEL GUIDANCE INDICATES A
CLOSED MID/UPPER LOW CENTER FORMING OVER CENTRAL/ERN PENN BEFORE
SCOOTING QUICKLY EAST OFF THE MID ATLANTIC COAST. AIR BEHIND THIS
SYSTEM WILL BE EVEN A FEW-SVRL DEG F COLDER THAN THE INITIAL LATE
WEEK CLIPPER. TEMPS SHOULD STEADILY FALL /FROM THEIR ALREADY BELOW
NORMAL VALUES/ SATURDAY AFTERNOON/EVENING...WITH A FEW SQUALLS
EMBEDDED IN THE LARGER SCALE AREAS OF LIGHTER SNOW.
AS THE SFC LOW RAPIDLY DEEPENS JUST OFF THE MID ATLANTIC/SRN NEW
ENGLAND COAST SAT NIGHT/SUNDAY...NW WINDS WILL INCREASE TO
SUSTAINED SPEEDS IN THE TEENS-LOW 20 KT RANGE WITH GUSTS UP TO 30
KTS...SIMILAR OR COLDER WIND CHILLS /THAN THURSDAY NIGHT`S ARE
EXPECTED BY VERY EARLY SUNDAY/.
A TRUE TASTE OF THE ARCTIC WILL BE PLATED UP FOR RESIDENTS OF
PENN SUNDAY...WITH MEAN GEFS 850 MB TEMPS BOTTOMING OUT IN THE
LOW-MID -20C RANGE - RESULTING IN SFC MAX TEMPS POSSIBLY STAYING
JUST BELOW ZERO ACROSS THE NRN MTNS...AND ONLY REACHING THE UPPER
SINGLE DIGITS TO MID TEENS AT BEST ACROSS THE CENTRAL AND SRN
PORTIONS OF THE STATE.
GEFS TEMP PLUMES AND ECENS MOS INDICATE THE COLDEST TEMPS OF THIS
OUTBREAK WILL LIKELY OCCUR SUN NIGHT...AS ARCTIC HIGH PRESSURE
SYSTEM BUILDS INTO THE STATE. SHOULD THE WIND DIMINISH AND SKIES
CLEAR OUT QUICK ENOUGH...WIDESPREAD RECORD MINS ARE POSSIBLE.
THE THIRD DIGGING SHORTWAVE /POSSIBLE CABOOSE/ TUESDAY...MAY HELP
TO BRIEFLY CARVE OUT THE MEAN ERN CONUS TROF A LITTLE FURTHER TO
THE WEST /WHILE TEAMING UP WITH SOME SRN STREAM ENERGY/ ALLOWING
FOR SOME GOMEX MOISTURE TO BE PICKED UP BY THE SYSTEM BEFORE IT
HEADS EAST- NORTHEAST TWD THE VA/MID ATLANTIC COAST. FOR NOW...AND
AT THIS TIME RANGE WILL GO WITH ABOVE CLIMO POPS ACROSS THE
CENTRAL AND EAST FOR CHC OF LIGHT SNOW OR SNOW SHOWERS /DEPENDING
ON WHETHER WE SEE A DOMINANT NRN STREAM CLIPPER...OR PHASING NRN
AND SRN STREAM FEATURES/. TEMPS MONDAY AND TUESDAY WILL SLOWLY
REBOUND BUT LIKELY STAY SEVERAL DEG F BELOW NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
ABOVE AVG CONFIDENCE IN PROLONGED IFR AT BFD/JST TERMINALS IN ZOB
SECTOR GIVEN INCREASINGLY COLD/BLUSTERY WNW FLOW IN WAKE OF
ARCTIC FRONT. MVFR CIGS SHOULD PREVAIL ACROSS THE CENTRAL TAFS
WITH LOW VFR 050 CIGS AT MDT/LNS. TIMING OF ARCTIC FRONT AND
ASSOCIATED BURSTS OF +SHSN/SNSQ WILL STILL NEED TO BE REFINED WITH
FAVORED WINDOW 12-15Z WEST...15-18Z CENTRAL AND 18-21Z SOUTHEAST.
SFC WINDS 270-300 BCMG 290-320 AND INCREASING INTO TONIGHT WITH
GUSTS 25-35KTS. CONDS SHOULD IMPROVE EAST OF THE MTNS BY TONIGHT
WITH RESTRICTIONS LKLY PERSISTING AT BFD/JST INTO FRIDAY MORNING.
OUTLOOK...
FRI...MVFR/IFR WITH -SHSN WEST EARLY...THEN GRADUALLY IMPROVING.
SAT...BCMG MVFR/IFR WITH -SN. FROPA FOLLOWED BY GUSTY WNW WINDS.
SUN...MVFR/IFR WEST IN -SHSN. STRONG GUSTY WNW WINDS.
MON...MVFR/IFR WITH -SHSN EARLY...THEN VFR LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WATCH FROM THIS EVENING THROUGH FRIDAY MORNING FOR
PAZ004>006-037-042.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 1 AM EST
FRIDAY FOR PAZ033.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/DEVOIR
LONG TERM...FITZGERALD/CERU
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1244 AM EST THU FEB 12 2015
.SYNOPSIS...
ARCTIC AIR WILL PUSH INTO THE COMMONWEALTH OVERNIGHT AND
THURSDAY. SNOW SHOWERS AND SNOW SQUALLS WILL CROSS CENTRAL
PENNSYLVANIA THURSDAY MORNING AND AFTERNOON BEFORE BITTERLY COLD
AIR ARRIVES AND DANGEROUSLY LOW WIND CHILLS OCCUR THURSDAY NIGHT
AND FRIDAY. ANOTHER POTENT UPPER LEVEL SHORTWAVE AND ASSOCIATED
CLIPPER WILL DELIVER AN EVEN COLDER SHOT OF ARCTIC AIR TO THE
REGION ON SUNDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
WATER VAPOR LOOP SHOWS POTENT SHORTWAVE DIVING SE ACROSS
WISCONSIN AT 0530Z. LG SCALE FORCING AHEAD OF THIS FEATURE IS
SUPPORTING SOME LIGHT SNOW FROM WESTERN NY STATE SW INTO OHIO.
ARCTIC COLD FRONT AT 05Z LIES ACROSS S ONTARIO INTO S MICHIGAN. AS
SHORTWAVE PRESSES EAST...EXPECT PERIODS OF LGT SNOW TO FALL OVR
THE ALLEGHENY PLATEAU EARLY THIS MORNING. UPSTREAM REPORTS ACROSS
SE OHIO/SW PA INDICATE SOME FZDZ...WHERE CLOUD TOP TEMPS REMAIN
RELATIVELY WARM. LATEST RAP OUTPUT INDICATES CLOUD TOP TEMPS AOA
-10C COULD SUPPORT A BIT OF FZDZ ACROSS THE LAUREL HIGHLANDS UNTIL
DEEPER/COLDER CLOUD TOPS ARRIVE ARND 08Z-09Z. SOME BRIEFLY HEAVIER
SNOW SHOWERS/SQUALLS COULD AFFECT PARTS OF THE NW MTNS ARND
DAWN...AS ARCTIC COLD FRONT ARRIVES.
LATEST NEAR TERM MDL OUTPUT CONTINUES TO INDICATE ONLY LIGHT
SNOW ACCUMS TONIGHT ACROSS THE ALLEGHENY PLATEAU. BLEND OF EARLIER MDL
QPF AND LATEST HRRR SUGGEST ACCUMS WILL GENERALLY BE LESS THAN AN
INCH ACROSS THE ALLEGHENY PLATEAU...WITH NO MORE THAN A DUSTING
LIKELY ELSEWHERE. CLOUD COVER AND SWRLY FLOW AHEAD OF APPROACHING ARCTIC
COLD FRONT SHOULD RESULT IN A RELATIVELY MILD NIGHT...WITH MIN
TEMPS MOSTLY IN THE 20S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
QPF VERY LIGHT AND UPSLOPE FETCH/FEED NOT ENTIRELY FAVORABLE FOR
SOMERSET COUNTY TO REALLY GET HAMMERED WITH HEAVY SNOW THIS
PERIOD. WILL TAKE THE WATCH AND CONVERT IT TO AN ADVY AND KEEP
MENTIONS OF BLSN...AS WINDS WILL BE PRETTY NASTY. ACCUMS WILL BE
TOUGH TO MEASURE ANYWAY...BUT QPF SO LIGHT - ON THE ORDER OF A
TENTH OF AN INCH - THAT ACCUMS MORE THAN 5 INCHES EVEN ON THE
RIDGES IS UNLIKELY.
WILL KEEP THINKING ABOUT THE WIND CHILL WATCH...IT LOOKS LIKE A
SOLID WARNING IN THE NORTH...BUT AN ADVY WILL BE NECESSARY
ELSEWHERE...BUT HOW FAR SE TO GO WITH IT IS A QUESTION. NO NEED TO
ACT RIGHT AWAY...AND WILL HOLD ONTO THE WIND CHILL WATCH FOR THE
TIME BEING.
PREV...
ARCTIC COLD FRONT WILL SWEEP THRU MOST OF CENTRAL PA BTWN 12Z-18Z
THU BASED ON 12Z GUIDANCE AND BTV SNSQ PARAMETER. SENT I80 EMAIL
NOTIFICATION FOR LINE OF SQUALLS EXPECTED TO CROSS CENTRAL PA THU
MORNING INTO THU AFTERNOON. STEEP LOWER TROPOSPHERIC LAPSE
RATES...COMBINED WITH STRONG LG SCALE FORCING AHEAD OF MID LVL
SHORTWAVE...WILL GENERATE LOCALLY HEAVY SNOW SHOWERS AND SQUALLS
EVEN INTO THE SUSQ VALLEY. ACCUMS THURSDAY SHOULD BE GENERALLY
LESS THAN AN INCH...BUT COULD POTENTIALLY CREATE FLASH FREEZE
CONCERNS OVR THE LOWER SUSQ VALLEY...WHERE ABV FREEZING TEMPS AND
INITIAL MELTING OF SNOW ON ROADS IS POSSIBLE.
OTHER CONCERN IS FOR STRONG UPSLOPE INTO THE LAUREL HIGHLANDS TO
PRODUCE SEVERAL INCHES OF SNOWFALL OVER SOMERSET COUNTY. IN COLLAB
WITH PBZ AND LWX...ISSUED WINTER STORM WATCH FOR SOMERSET COUNTY
WITH A GENERAL 4 TO 8 INCHES WITH HIGHER AMOUNTS POSSIBLE ON THE
RIDGES FROM ~12Z THU TO 06Z FRI NIGHT.
NW WINDS INCREASING TO 10-18 KTS WITH GUSTS OCNLY TO 25-30 KTS IN
THE AFTERNOON WILL USHER IN BITTERLY COLD TEMPS AND WIND CHILLS.
THE STRONGEST WINDS WILL LIKELY NOT DEVELOP UNTIL THURSDAY
EVENING...AS PRES GRADIENT TIGHTENS WEST OF RAPIDLY DEVELOPING
COASTAL STORM SOUTH OF CAPE COD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CURRENT ENEMBLES AND MODEL SOUNDINGS GIVE FURTHER CREDENCE AND
SUPPORT FOR FREQUENT GUSTS TO ARND 35KTS ACROSS MUCH OF CENTRAL
PA BTWN 00Z- 06Z FRIDAY. GUSTY WINDS WILL CONTINUE THROUGH FRIDAY
MORNING. THE STRONG WINDS IN CONJUNCTION W/ARRIVAL OF ARCTIC AIR
MASS WILL LIKELY RESULT WIDESPREAD WIND CHILLS THU NIGHT BTWN
10-20 BLW ZERO. ACROSS THE N MTNS...APPARENT TEMPS IN THE 25-30BLW
RANGE ARE POSSIBLE. CONFIDENCE IN TEMPERATURES AND HAVE THEREFORE
ISSUED A WIND CHILL WATCH UP THERE AND WILL CONTINUE TO MENTION
POSSIBILITY OF DANGEROUS WCHILLS ACROSS THE CENTRAL COUNTIES.
MOSTLY FROZEN LAKES AND DRYNESS OF ARCTIC AIR MASS SHOULD PRECLUDE
ANYTHING MORE THAN SCT -SHSN OVR THE W MTNS THU NIGHT WITH ANY
ADDITIONAL ACCUMS LESS THAN AN INCH.
FRIDAY WILL LIKELY BE ONE OF THE COLDEST DAYS OF THE WINTER
SEASON SO FAR WITH ANOMALOUSLY LOW GEFS MEAN 925 MB TEMPS OF ARND
-18C LIKELY SUPPORTING HIGH TEMPS NO BETTER THAN THE SINGLE
DIGITS ACROSS THE NORTHERN MTNS...TO THE UPPER TEENS ACROSS THE
SOUTHERN VALLEYS.
AN EXTENSIVE RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION FRIDAY
INTO EARLY FRIDAY NIGHT WITH SLOWLY DECREASING NW WINDS AND PARTLY
TO MOSTLY SUNNY SKIES ACROSS THE CENTRAL AND SE ZONES. THE NW MTNS
MAY HAVE A TOUGH TIME BREAKING UP THE SHALLOW STRATO CU WITH A
CHANCE FOR FLURRIES FRIDAY NIGHT INTO SATURDAY.
THE CLIPPER WILL TRACK ACROSS THE CWA LATE FRIDAY NIGHT INTO
SATURDAY...ACCOMPANIED BY NUMEROUS SNOW SHOWERS INTO SATURDAY
DAYTIME...AND PERIODS OF STEADY SNOW INTO SATURDAY EVENING. MODELS
DIFFER ON THE PLACEMENT OF THE UPPER LEVEL LOW...AND AS SUCH THERE
IS SOME VARIANCE ON THE AMOUNT OF QPF AND CORRESPONDING SNOW
AMOUNTS WITH THIS SYSTEM. THE EC MODEL GUIDANCE INDICATES A
CLOSED MID/UPPER LOW CENTER FORMING OVER CENTRAL/ERN PENN BEFORE
SCOOTING QUICKLY EAST OFF THE MID ATLANTIC COAST. AIR BEHIND THIS
SYSTEM WILL BE EVEN A FEW-SVRL DEG F COLDER THAN THE INITIAL LATE
WEEK CLIPPER. TEMPS SHOULD STEADILY FALL /FROM THEIR ALREADY BELOW
NORMAL VALUES/ SATURDAY AFTERNOON/EVENING...WITH A FEW SQUALLS
EMBEDDED IN THE LARGER SCALE AREAS OF LIGHTER SNOW.
AS THE SFC LOW RAPIDLY DEEPENS JUST OFF THE MID ATLANTIC/SRN NEW
ENGLAND COAST SAT NIGHT/SUNDAY...NW WINDS WILL INCREASE TO
SUSTAINED SPEEDS IN THE TEENS-LOW 20 KT RANGE WITH GUSTS UP TO 30
KTS...SIMILAR OR COLDER WIND CHILLS /THAN THURSDAY NIGHT`S ARE
EXPECTED BY VERY EARLY SUNDAY/.
A TRUE TASTE OF THE ARCTIC WILL BE PLATED UP FOR RESIDENTS OF
PENN SUNDAY...WITH MEAN GEFS 850 MB TEMPS BOTTOMING OUT IN THE
LOW-MID -20C RANGE - RESULTING IN SFC MAX TEMPS POSSIBLY STAYING
JUST BELOW ZERO ACROSS THE NRN MTNS...AND ONLY REACHING THE UPPER
SINGLE DIGITS TO MID TEENS AT BEST ACROSS THE CENTRAL AND SRN
PORTIONS OF THE STATE.
GEFS TEMP PLUMES AND ECENS MOS INDICATE THE COLDEST TEMPS OF THIS
OUTBREAK WILL LIKELY OCCUR SUN NIGHT...AS ARCTIC HIGH PRESSURE
SYSTEM BUILDS INTO THE STATE. SHOULD THE WIND DIMINISH AND SKIES
CLEAR OUT QUICK ENOUGH...WIDESPREAD RECORD MINS ARE POSSIBLE.
THE THIRD DIGGING SHORTWAVE /POSSIBLE CABOOSE/ TUESDAY...MAY HELP
TO BRIEFLY CARVE OUT THE MEAN ERN CONUS TROF A LITTLE FURTHER TO
THE WEST /WHILE TEAMING UP WITH SOME SRN STREAM ENERGY/ ALLOWING
FOR SOME GOMEX MOISTURE TO BE PICKED UP BY THE SYSTEM BEFORE IT
HEADS EAST- NORTHEAST TWD THE VA/MID ATLANTIC COAST. FOR NOW...AND
AT THIS TIME RANGE WILL GO WITH ABOVE CLIMO POPS ACROSS THE
CENTRAL AND EAST FOR CHC OF LIGHT SNOW OR SNOW SHOWERS /DEPENDING
ON WHETHER WE SEE A DOMINANT NRN STREAM CLIPPER...OR PHASING NRN
AND SRN STREAM FEATURES/. TEMPS MONDAY AND TUESDAY WILL SLOWLY
REBOUND BUT LIKELY STAY SEVERAL DEG F BELOW NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
FEW SNOW SHOWERS TO THE EAST.
NOT SEEING MUCH TO THE WEST.
EXPECT CONDITIONS TO LOWER...AS HIGHER DEWPOINTS WORK EASTWARD
FROM OH.
EARLIER DISCUSSION BELOW.
00Z...
MAIN AREA OF HEAVIER RADAR RETURNS NOW OVER NORTH CENTRAL PA.
MADE A FEW ADJUSTMENTS TO THE 00Z TAF PACKAGE.
21Z...
MADE SOME LARGE CHANGES TO TAFS AT 21Z.
FIRST ISSUE IS FAST MOVING BANDS OF SNOW SHOWERS. SNOW MAY COME
DOWN HARD FOR A SHORT TIME. MODELS FAR FASTER WITH THIS THAN
EVEN THE 06Z RUN LAST EVENING BEFORE I LEFT. BANDS OF SNOW WELL
AHEAD OF THE COLD FRONT AND UPPER LEVEL TROUGH.
SECOND ISSUE WAS TO ADD ANOTHER GROUP PRIOR TO 18Z THU...GUSTY
WINDS LIKELY BEFORE THAT TIME. SOME DIRECTIONAL SHEAR...THUS
HARD TO SEE A LOT OF HEAVY SQUALLS WITH THE FRONT OR OFF THE
LAKES.
OUTLOOK...
FRI...MVFR/IFR WITH -SHSN WEST...MAINLY EARLY. VFR LATE.
SAT...MVFR/IFR WITH -SN.
SUN...MVFR/IFR WEST IN -SHSN. VERY COLD TEMPERATURES...AND GUSTY
WINDS ALL AREAS.
MON...MVFR/IFR WITH -SHSN EARLY...THEN VFR LATE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WATCH FROM THIS EVENING THROUGH FRIDAY MORNING FOR
PAZ004>006-037-042.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 1 AM EST
FRIDAY FOR PAZ033.
&&
$$
SYNOPSIS...DANGELO/DEVOIR
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/DEVOIR
LONG TERM...FITZGERALD/CERU
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
116 PM EST THU FEB 12 2015
.SYNOPSIS...
EXPECT THE ROBUST INFLUX OF COLD CANADIAN AIR TO CONTINUE THROUGH
FRIDAY. AN ARCTIC COLD FRONT WILL CROSS THE AREA SATURDAY
EVENING...BRINGING ANOTHER VERY COLD AIRMASS TO THE REGION BY SUNDAY.
MOISTURE IS FORECAST TO SPREAD BACK INTO THE AREA AT THE TAIL END OF
THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
100 PM UPDATE...COLD ADVECTION HAS FINALLY GOTTEN UNDERWAY IN THE
MTNS/FOOTHILLS WITH NW GUSTS REALLY PICKING UP AND TEMPS DROPPING.
THE DELAYED WARMING HAS ALLOWED MUCH OF THE PIEDMONT TO REACH THE
UPPER 50S TO NEAR 60. REVISED TRENDS ALLOW THE PIEDMONT TO RISE A
LITTLE HIGHER BEFORE REACHING MAXES AN HR OR TWO EARLIER THAN CLIMO
BEFORE BEGINNING THE PLUNGE. HOWEVER...PERHAPS DUE TO SLIGHTLY
WINDIER CONDITIONS IN THE LATE NIGHT HRS...VIRTUALLY ALL GUIDANCE
TRENDED A LITTLE WARMER WITH LOWS TONIGHT.
BETTER MOISTURE HAS ALSO NOW REACHED THE MOUNTAINS AS ANTICIPATED
WITH RADAR RETURNS IN THE SMOKIES AND BALD MTNS SUPPORTING FAIRLY
STEADY PRECIP RATES. GUIDANCE DOES NOT REFLECT MUCH IN THE WAY OF
QPF INTO THE AFTN...BUT BASED ON SATELLITE AND RADAR AT LEAST
PERIODIC SNOWFALL IS LIKELY TO CONTINUE THRU MUCH OF THE AFTN. PROG
SOUNDINGS FROM RAP AND NAM STILL HINT AT SOME CONVECTIVE POTENTIAL.
HIT THE SNOW RATIOS A BIT HARDER THRU MID AFTN IN LINE WITH THIS
THINKING. SNOW AMOUNTS STILL JUST SUPPORT AN ADVISORY IN CONJUNCTION
WITH THE WINDS AND ASSOCIATED BLOWING SNOW AND VSBY RESTRICTIONS.
REVISED MINS AND WINDS STILL SUPPORT THE GOING WIND CHILL ADVY AND
WIND ADVY FOR THE MTNS. WILL TAKE A FINAL LOOK AT THESE BEFORE
FINISHING UP THE AFTN PACKAGE HOWEVER.
AS OF 315 AM EST THURSDAY...A POTENT UPPER SHORTWAVE TROUGH WILL DIG
SOUTHEASTWARD TOWARD THE SOUTHEASTERN STATES TODAY. POPS WILL
QUICKLY RAMP UP ALONG THE TN LINE THROUGH THE MORNING AS THE
AFOREMENTIONED LLVL MOISTURE REACHES THE APPALACHIANS WITHIN
INCREASING CAA NW FLOW REGIME. AS THE POTENT UPPER SHORTWAVE TROUGH
SWINGS ACROSS THE REGION AND AN ARCTIC HIGH PRESSURE BUILDS IN FROM
THE NW TODAY...H85 TEMPS OVER THE NC MTNS SHOULD PLUMMET INTO -6C BY
12Z THIS MORNING...AND INTO -13-15C RANGE BY 18Z TODAY. ALSO...LLVL
INSTABILITY WILL BE PRESENT ALONG THE TN LINE WHEN THE TROUGH AXIS
ASSOCIATED WITH BEST UPPER FORCING PASSES OVERHEAD THIS
AFTERNOON...AIDING IN BETTER SNOWFALL RATE IN ITS WAKE.
THEREFORE...POPS WILL PEAK IN THE HIGH LIKELY RANGE OVER THE
NORTHERN NC MTNS BY MIDDAY WITH 1-2 INCHES OF SNOW ACCUMS LIKELY
THRU THIS AFTERNOON. THE SNOW SHOULD TAPER OFF TOWARD LATE THIS
AFTERNOON AS DEEP LAYER DRYING WILL OCCUR BEHIND THE DEPARTING UPPER
TROUGH.
AS FOR THE WINDS...A VERY TIGHT SURFACE PRESSURE GRADIENT WILL SET
UP ACROSS THE CWA TODAY...LEADING TO INCREASING NW WINDS TO AROUND
20-30MPH...GUSTS TO AROUND 45-50MPH OVER THE NC MTNS. WITH THE
COMBINATION OF 1-2" OF ACCUMULATING SNOW AND STRONG NW WINDS...WILL
CONTINUE TO HIGHLIGHT THESE IN THE WINTER WEATHER ADVISORY OVER THE
TN BORDER COUNTIES. ELSEWHERE ACROSS THE HIGHER TERRAIN AND
FOOTHILLS...WILL CONTINUE THE WIND ADVISORY TODAY. AREAS OVER THE
PIEDMONT WILL SEE BELOW WIND ADVISORY CRITERIA OF 15-25 MPH OF NW
WINDS...GUSTING TO AROUND 30-40 MPH RANGE THIS AFTERNOON. THE GUSTY
WINDS SHOULD PERSIST AT LEAST THRU LATE TONIGHT BUT THE CONDITIONS
WILL DRY OUT ACROSS THE TN LINE WHERE THE CURRENT WINTER ADVISORY IS
EFFECTIVE THRU THIS EVENING. THEREFORE...ANOTHER WIND ADVISORY WAS
ISSUED TO COVER PERSISTING GUSTY WINDS ACROSS ENTIRE NC
MTN/FOOTHILLS ZONES FROM 7PM THROUGH MIDNIGHT.
TEMPS THIS AFTERNOON WILL REMAIN NEAR OR BELOW FREEZING ACROSS THE
NC MTNS...AMD MID TO UPPER 40S ELSEWHERE. TEMPS TONIGHT WILL PLUMMET
INTO THE SINGLE DIGITS/LOW 10S OVER THE NC MTNS...AND INTO U10S/L20S
ACROSS THE PIEDMONT. WITH THE HELP OF 7-10 MPH WINDS...WIND CHILL
VALUES WILL STAY 5 BELOW ACROSS THE NC MTNS. THEREFORE...WILL ISSUE
A WIND CHILL ADVISORY TONIGHT INTO FRI MORNING.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 205 AM THU...HIGH PRESSURE BUILDS IN FRIDAY BRINGING AN END TO
THE GUSTY WINDS ACROSS THE AREA AND ANY LOW WIND CHILL VALUES. THERE
WILL BE QUITE A BIT OF MID AND HIGH CLOUDS MOVING ACROSS THE AREA
DURING THE DAY. THE AIR MASS IS STILL QUITE COLD WITH HIGHS AROUND
15 DEGREES BELOW NORMAL.
A HIGH AMPLITUDE TROF WILL REMAIN OVER THE ERN CONUS FRI NITE THRU
SUN NITE AS A DEEP VORTEX MOVES SEWD OUT OF ONTARIO TO REINFORCE
ARCTIC AIR ACROSS THE SE. A MODEST REBOUND IN TEMPERATURES IS
EXPECTED FRI NIGHT AND SAT AHEAD OF AN ARCTIC COLD FRONT MOVING
TOWARD THE AREA. THE FRONT CROSSES THE REGION FROM THE NW LATE SAT
OR SAT NITE. A BRIEF SHOT OF MOISTURE IS EXPECTED WITH AND BEHIND
THE COLD FRONT ON SATURDAY. THEREFORE...EXPECT ANOTHER ROUND OF NW
FLOW SNOW SHOWERS ACROSS THE TN BORDER COUNTIES. LOW LEVEL
INSTABILITY WILL BE RELATIVELY HIGH AND IN THE ICE CRYSTAL GROWTH
REGION...WHICH COULD LEAD TO SNOW SQUALLS AND SNOWFALL AMOUNTS
HIGHER THAN WOULD BE EXPECTED GIVEN THE QUICK SHOT OF PRECIP AND
RELATIVELY LIGHT QPF. THE STRENGTH OF THE COLD AIR WILL BE THE BIGGER
STORY. THE GEFS ENSEMBLE MEAN H85 TEMP ANOMALIES WILL BE UP TO 3
STANDARD DEVIATIONS BELOW NORMAL BY SUNDAY. THE PRES GRADIENT
BETWEEN THE DEPARTING LOW AND 1044 ARCTIC HIGH OVER THE PLAINS WILL
PUSH WIND CHILL VALUES TO NEAR WARNING LEVELS IN THE NC MOUNTAINS
SUN MORNING...WITH ADVISORY CRITERIA OVER MUCH OF THE NC FOOTHILLS
AND PIEDMONT...AND THE MTNS OF THE UPSTATE AND NE GA. STRONG WIND
GUSTS ARE ALSO POSSIBLE...WITH AT LEAST ADVISORY LEVEL GUSTS ACROSS
THE NC MTNS...POSSIBLY REACHING WARNING LEVEL ACROSS THE HIGHER
ELEVATIONS. LOWS SAT NITE WILL BE 15 TO 20 DEGREES BELOW NORMAL
WHILE HIGHS SUNDAY WILL BE 20 TO 25 DEGREES BELOW NORMAL...WITH MOST
OF OUR NC COUNTIES NOT REACHING FREEZING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 AM THURSDAY...CONFIDENCE REMAINS ON THE LOW SIDE FOR THE
MEDIUM RANGE PART OF THE FCST...OWING TO SOME CONTINUED RUN-TO-RUN
CONSISTENCY ISSUES WITH THE MODEL GUIDANCE FOR THE NEXT SYSTEM
TOWARD THE MIDDLE OF NEXT WEEK. ALTHOUGH THERE WILL BE SOME
LINGERING WIND AND WIND CHILL ISSUES SUNDAY MORN...THE REST OF THE
FIRST PART SEEMS QUIET ENOUGH WITH A FLAT UPPER RIDGE MOVING IN AND
ACROSS THE CAROLINAS SUNDAY NIGHT THROUGH MONDAY. THE PROBLEMS BEGIN
IN EARNEST LATE MONDAY AS MOISTURE RETURNS AHEAD OF A DIGGING UPPER
TROF OVER THE PLAINS...AND FORCING SPREADS OVER THE REGION FROM THE
SW IN THE FORM OF ISENTROPIC LIFT AND UPPER DIVERGENCE IN THE RIGHT
ENTRANCE REGION OF A STRENGTHENING UPPER JET TO OUR N. THE CONSENSUS
OF THE OPERATIONAL MODELS IS THAT PRECIP WILL DEVELOP FROM THE SW
ACROSS THE FCST AREA MONDAY NIGHT...MAINLY OVER THE MTNS AND NE
GEORGIA BEFORE SUNRISE...AND THEN THE REST OF THE FCST AREA BY NOON
TUESDAY. AS THESE DEVELOPMENTS HAPPEN...A RELATIVELY COOL BUT
RELATIVELY WEAK HIGH WILL BE MOVING OFF TO THE EAST. THAT WILL
PROVIDE THE OPPORTUNITY FOR AN IN-SITU WEDGE TO DEVELOP WITH LOW
LEVEL THICKNESS LOW ENOUGH TO RESULT IN THE THREAT OF A WINTRY MIX
AT PRECIP ONSET. THE MOST LIKELY SCENARIO FOR NOW...BASED ON THE
GUIDANCE...IS FOR A SHORT PERIOD OF SLEET/SNOW AND THEN A SHORT
PERIOD OF FREEZING RAIN AS THE PRECIP MOVES IN AS A WARM NOSE
DEVELOPS. WILL STAY CONSISTENT WITH THE GUIDANCE AND INCLUDE THE
WINTRY MIX. HOWEVER...UNCERTAINTY IN THE TIMING SMEARS THIS OUT IN
THE FCST PROCESS...SO THE FCST MIGHT LOOK MORE DIRE THAN IT ACTUALLY
WILL BE. FREEZING RAIN EVENTS BECOME MORE RARE AS WE GET INTO
MID/LATE FEBRUARY...SO THE MOST LIKELY TREND WILL BE FOR WARM
ADVECTION TO WIN OUT AND LIMIT THE AMOUNT OF ANY WINTRY MIX. THAT
SAID...THE GFS AND THE ECMWF BOTH TAKE THE PRIMARY LOW UP THE SPINE
OF THE APPALACHIANS...WHICH COULD KEEP THE WINTRY MIX IN LONGER
BEFORE CHANGING ALL PRECIP OVER TO RAIN ON TUESDAY. HAVE KEPT THE
PRECIP PROBABILITY LIMITED TO THE LIKELY CATEGORY. THINGS GET
COMPLICATED AGAIN TUESDAY NIGHT AS THE ECMWF IS MUCH SLOWER MOVING
THE PRIMARY LOW NORTH OF THE AREA AND THE ASSOCIATED COLD FRONT IN
FROM THE WEST. THERE COULD BE A PERIOD OF FREEZING RAIN BEHIND THE
FRONT BEFORE THE DEEPER COLD AIR MOVES IN CHANGING THE PRECIP TO
SNOW. HOWEVER...THE GFS IS FASTER AND ANY FREEZING RAIN WOULD BE
BRIEF. THE GFS ALSO CONTINUES TO SUGGEST SOME DESTABILIZATION IS
POSSIBLE ACROSS THE SRN CWFA AHEAD OF THE FRONT. THAT COULD SPELL
SOME CONCERN FOR SEVERE WEATHER. EVEN THE SLOWER ECMWF HAS THE FRONT
BLASTING THROUGH ON WEDNESDAY...AND THE COLD AIR FOLLOWS ACROSS THE
REST OF THE FCST AREA. ONCE AGAIN...CONFIDENCE IS NOT GREAT...SO DO
NOT PUT TOO MUCH STOCK IN THE WINTER PRECIP POTENTIAL JUST YET.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...VFR WILL PREVAIL AT ALL TERMINALS THRU THE
PERIOD. THE ONLY SITE AT RISK OF A RESTRICTIVE CIG IS KAVL...WHICH
CANNOT BE COMPLETELY RULED OUT AS SEEING AN MVFR CIG AT TIMES THIS
AFTN DUE TO UPSLOPE-DRIVEN CLOUD COVER SPILLING OVER THE SPINE OF
THE APPALACHIANS. -SHSN AND MVFR/IFR VSBYS ARE LIKELY THRU THE AFTN
AT THE HIGHER ELEVATIONS...ESP NEAR THE TENN BORDER...BUT THESE
SHOULD NOT AFFECT KAVL. GUSTY WINDS WILL BE THE PRIMARY CONCERN THRU
THIS EVENING AROUND THE REGION AS COLD HIGH PRESSURE PUSHES
IN...MAINTAINING A DEEP MIXED LAYER AND TIGHT PRS GRADIENT. AT LEAST
A COUPLE GUSTS OF 30-35 KT MAY OCCUR ACRS THE AREA...WITH KAVL
SEEING THE STRONGEST GUSTS. DIRECTIONS WILL BE SOLIDLY NW THRU THE
NIGHT THOUGH THE GRADIENT WILL RELAX ENOUGH TO ALLOW GUSTS TO CEASE
AFTER MIDNIGHT. INCREASING MID-UPPER MOISTURE FROM W TO E WILL BRING
PATCHY 150-200 CIGS FRI MRNG.
OUTLOOK...DRY BUT COLD HIGH PRESSURE WILL REMAIN OVER THE AREA THRU
SAT. HENCE...NO RESTRICTIONS. ANOTHER ARCTIC COLD FRONT WILL CROSS
THE AREA BY SAT NIGHT...WITH WINDY CONDITIONS AND MUCH COLDER
TEMPERATURES ARRIVING. A LOW PRESSURE SYSTEM WILL PASS THROUGH THE
AREA MONDAY NIGHT INTO TUESDAY NIGHT...LIKELY BRINGING PRECIPITATION
AND RESTRICTIONS.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 74% HIGH 100% HIGH 100% HIGH 100%
KHKY MED 77% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
WINDY CONDITIONS WILL DEVELOP ACROSS THE FORECAST AREA TODAY.
ALTHOUGH MIN RH MAY NOT QUITE BOTTOM OUT AT CRITICAL VALUES THIS
AFTN...IT COULD BE CLOSE...AND RAPID DRYING OF FUELS MAY QUICKLY
ENHANCE FIRE DANGER. WILL POST FIRE DANGER STATEMENT FOR ALL BUT THE
NC MTNS WHERE RH WILL REMAIN HIGHER. IN ADDITION...A COMBINATION OF
WINDY CONDITIONS AND DIURNALLY LOW RH WILL CONTINUE AT TIMES FRI
THROUGH SUNDAY. A SERIES OF FIRE DANGER STATEMENTS...OR POSSIBLE RED
FLAG PRODUCTS...COULD BE NEEDED AT SOME POINT.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ053-058-059-
062>065-501-503-505-507-509.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NCZ033-
048>052.
WIND ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST TONIGHT
FOR NCZ033-048>052.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY
FOR NCZ033-048>053-058-059-062-063.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...JOH/WIMBERLEY
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...WIMBERLEY
FIRE WEATHER...JOH
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
917 AM CST THU FEB 12 2015
.UPDATE...
UPDATED FOR ADDING MORNING CLOUD COVER...SNOW FLURRIES AND HIGHER
WIND GUSTS.
&&
.DISCUSSION...
POST FRONTAL ARCTIC AIRMASS IS UNDERWAY ACROSS THE MIDSOUTH WITH
BAND OF STRATOCUMULUS SURGING SOUTH. OCCASIONAL SNOW FLURRIES HAVE
ALSO BEEN REPORTED ACROSS PORTIONS OF WEST TENNESSEE. FINALLY
SEEING HIGHER WIND GUSTS ACROSS NORTHEAST ARKANSAS AND THE
BOOTHEEL OF MISSOURI. HAVE UPDATED THE MORNING FORECAST
ACCORDINGLY.
JAB
&&
.PREV DISCUSSION... /ISSUED 538 AM CST THU FEB 12 2015/
UPDATE...
UPDATED FOR 12Z AVIATION DISCUSSION BELOW.
PREV DISCUSSION... /ISSUED 421 AM CST THU FEB 12 2015/
DISCUSSION...09Z SURFACE ANALYSIS PLACES AN ARCTIC COLD FRONT
FROM THE APPALACHIANS BACK THROUGH GEORGIA AND THE NORTHERN GULF
COAST. BEHIND THIS FRONT...COLD AIR ADVECTION HAS DROPPED
TEMPERATURES INTO THE MIDDLE 20S NORTH OF I-40 AND 3OS SOUTH AS OF
4 AM CST. WINTRY PRECIPITATION POTENTIAL EARLY NEXT WEEK IS THE
PREDOMINANT CONCERN AND FOCUS IN THIS MORNING/S FORECAST ISSUANCE.
SHORT TERM...(TODAY THROUGH SATURDAY)...COLD AIR ADVECTION BEHIND
AN ARCTIC COLD FRONT WILL BRING PRECIPITATION FREE WEATHER TO THE
MID SOUTH TODAY AND TONIGHT. AS A RESULT...TEMPERATURES WILL
ONLY RISE THE 30S AT MOST LOCATIONS WITH LOW TEMPERATURES TONIGHT
FALLING BACK INTO THE TEENS TO AROUND 20 DEGREES.
TEMPERATURES WILL MODERATE INTO FRIDAY NIGHT ACROSS THE MID SOUTH
AS SOUTHERLY WINDS ON THE BACK SIDE OF HIGH PRESSURE RETURN TO THE
LOWER MISSISSIPPI VALLEY. ANOTHER COLD FRONT IS EXPECTED TO PUSH
THROUGH THE REGION ON SATURDAY BUT NO PRECIPITATION IS
ANTICIPATED AT THIS MOMENT WITH ITS PASSAGE AS MODELS SUGGEST BEST
MOISTURE AND FORCING WILL BE TO THE NORTHEAST OF THE FORECAST
AREA.
LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)...COLD AIR
ADVECTION BEHIND ANOTHER ARCTIC COLD FRONT WILL BRING VERY COLD
TEMPERATURES IN THE TEENS AT MOST LOCATIONS BY SUNDAY MORNING.
THESE COLD TEMPERATURES COMBINED WITH GUSTY NORTH-NORTHEAST WINDS
MAY RESULT IN WIND CHILL READINGS APPROACHING ZERO OR FALLING
BELOW ZERO LATE SATURDAY NIGHT TOWARDS SUNDAY MORNING.
HOWEVER...THE PRIMARY CONCERN IN THE LONG TERM FORECAST IS FOR
WASHINGTON/S BIRTHDAY INTO NEXT TUESDAY NIGHT AS THE COLD FRONT
BEGINS TO RETURN BACK NORTH AS A WARM FRONT MONDAY AND A STRONGER
ARCTIC COLD FRONT DIVES SOUTH INTO THE LOWER MISSISSIPPI VALLEY ON
TUESDAY. EVEN THOUGH LONG TERM MODELS HAVE BEEN TRENDING SLIGHTLY
COOLER...UNCERTAINTY STILL REMAINS WITH EXACT PRECIPITATION TYPES.
LAST NIGHT/S 00Z GFS/ECMWF MODEL SOUNDINGS INDICATED A POTENTIAL
FOR RAIN...FREEZING RAIN...SLEET...AND SNOW NORTH OF I-40 AT TIMES
THROUGH THE PERIOD...AND PERHAPS REACHING AS FAR SOUTH AS THE
I-40 CORRIDOR. AS COLDER AIR FILTERS INTO THE REGION LATER
TUESDAY INTO TUESDAY NIGHT...ANY RAIN SHOULD TRANSITION TO SNOW
BEFORE ENDING. IN ADDITION TO THE WINTRY PRECIPITATION
POTENTIAL...ELEVATED INSTABILITY MAY RESULT IN THE FORMATION OF
EMBEDDED THUNDERSTORMS ON TUESDAY MAINLY ALONG AREAS TOWARDS CENTRAL
MISSISSIPPI. WILL MENTION WINTRY PRECIPITATION THREAT IN
HAZARDOUS WEATHER OUTLOOK. EXACT PRECIPITATION TYPES MAY NEED TO
BE ADJUSTED AS NECESSARY AS THIS POTENTIAL EVENT DRAWS CLOSER.
STAY TUNED... TEMPERATURES THROUGH THIS PERIOD OVERALL ARE
EXPECTED TO REMAIN WELL BELOW NORMAL FOR FEBRUARY.
CJC
AVIATION...
12Z TAFS
ARCTIC AIR WILL SPREAD THROUGH THE MIDSOUTH TODAY AND PERSIST
THROUGH THE PERIOD. A CLOUD DECK ABOVE FL025 WAS DROPPING SOUTH
THROUGH MO AT 1130Z. HRRR MODEL GUIDANCE SHOWED THIS DECK
AFFECTING MIDSOUTH TERMINALS PRIOR TO DISSIPATION BY 18Z.
OTHERWISE... VFR WILL PREVAIL THE NEXT 24 HOURS.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
538 AM CST THU FEB 12 2015
.UPDATE...
UPDATED FOR 12Z AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION... /ISSUED 421 AM CST THU FEB 12 2015/
DISCUSSION...09Z SURFACE ANALYSIS PLACES AN ARCTIC COLD FRONT
FROM THE APPALACHIANS BACK THROUGH GEORGIA AND THE NORTHERN GULF
COAST. BEHIND THIS FRONT...COLD AIR ADVECTION HAS DROPPED
TEMPERATURES INTO THE MIDDLE 20S NORTH OF I-40 AND 3OS SOUTH AS OF
4 AM CST. WINTRY PRECIPITATION POTENTIAL EARLY NEXT WEEK IS THE
PREDOMINANT CONCERN AND FOCUS IN THIS MORNING/S FORECAST ISSUANCE.
SHORT TERM...(TODAY THROUGH SATURDAY)...COLD AIR ADVECTION BEHIND
AN ARCTIC COLD FRONT WILL BRING PRECIPITATION FREE WEATHER TO THE
MID SOUTH TODAY AND TONIGHT. AS A RESULT...TEMPERATURES WILL
ONLY RISE THE 30S AT MOST LOCATIONS WITH LOW TEMPERATURES TONIGHT
FALLING BACK INTO THE TEENS TO AROUND 20 DEGREES.
TEMPERATURES WILL MODERATE INTO FRIDAY NIGHT ACROSS THE MID SOUTH
AS SOUTHERLY WINDS ON THE BACK SIDE OF HIGH PRESSURE RETURN TO THE
LOWER MISSISSIPPI VALLEY. ANOTHER COLD FRONT IS EXPECTED TO PUSH
THROUGH THE REGION ON SATURDAY BUT NO PRECIPITATION IS
ANTICIPATED AT THIS MOMENT WITH ITS PASSAGE AS MODELS SUGGEST BEST
MOISTURE AND FORCING WILL BE TO THE NORTHEAST OF THE FORECAST
AREA.
LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)...COLD AIR
ADVECTION BEHIND ANOTHER ARCTIC COLD FRONT WILL BRING VERY COLD
TEMPERATURES IN THE TEENS AT MOST LOCATIONS BY SUNDAY MORNING.
THESE COLD TEMPERATURES COMBINED WITH GUSTY NORTH-NORTHEAST WINDS
MAY RESULT IN WIND CHILL READINGS APPROACHING ZERO OR FALLING
BELOW ZERO LATE SATURDAY NIGHT TOWARDS SUNDAY MORNING.
HOWEVER...THE PRIMARY CONCERN IN THE LONG TERM FORECAST IS FOR
WASHINGTON/S BIRTHDAY INTO NEXT TUESDAY NIGHT AS THE COLD FRONT
BEGINS TO RETURN BACK NORTH AS A WARM FRONT MONDAY AND A STRONGER
ARCTIC COLD FRONT DIVES SOUTH INTO THE LOWER MISSISSIPPI VALLEY ON
TUESDAY. EVEN THOUGH LONG TERM MODELS HAVE BEEN TRENDING SLIGHTLY
COOLER...UNCERTAINTY STILL REMAINS WITH EXACT PRECIPITATION TYPES.
LAST NIGHT/S 00Z GFS/ECMWF MODEL SOUNDINGS INDICATED A POTENTIAL
FOR RAIN...FREEZING RAIN...SLEET...AND SNOW NORTH OF I-40 AT TIMES
THROUGH THE PERIOD...AND PERHAPS REACHING AS FAR SOUTH AS THE
I-40 CORRIDOR. AS COLDER AIR FILTERS INTO THE REGION LATER
TUESDAY INTO TUESDAY NIGHT...ANY RAIN SHOULD TRANSITION TO SNOW
BEFORE ENDING. IN ADDITION TO THE WINTRY PRECIPITATION
POTENTIAL...ELEVATED INSTABILITY MAY RESULT IN THE FORMATION OF
EMBEDDED THUNDERSTORMS ON TUESDAY MAINLY ALONG AREAS TOWARDS CENTRAL
MISSISSIPPI. WILL MENTION WINTRY PRECIPITATION THREAT IN
HAZARDOUS WEATHER OUTLOOK. EXACT PRECIPITATION TYPES MAY NEED TO
BE ADJUSTED AS NECESSARY AS THIS POTENTIAL EVENT DRAWS CLOSER.
STAY TUNED... TEMPERATURES THROUGH THIS PERIOD OVERALL ARE
EXPECTED TO REMAIN WELL BELOW NORMAL FOR FEBRUARY.
CJC
&&
.AVIATION...
12Z TAFS
ARCTIC AIR WILL SPREAD THROUGH THE MIDSOUTH TODAY AND PERSIST
THROUGH THE PERIOD. A CLOUD DECK ABOVE FL025 WAS DROPPING SOUTH
THROUGH MO AT 1130Z. HRRR MODEL GUIDANCE SHOWED THIS DECK
AFFECTING MIDSOUTH TERMINALS PRIOR TO DISSIPATION BY 18Z.
OTHERWISE... VFR WILL PREVAIL THE NEXT 24 HOURS.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
Area Forecast Discussion
National Weather Service Spokane WA
837 AM PST THU FEB 12 2015
.SYNOPSIS...
A weak warm front will cross the area today bringing light rain
or sprinkles to portions of the Inland Northwest. The greatest
threat of measurable rain will impact locations near the Cascades
and Canadian border. Otherwise look for the warm temperatures to
continue with a few record highs possible on Friday and Saturday.
A weak cold front will move through the region on Saturday
bringing a good chance of precipitation for most locations. An
even stronger cold front will push through the area on Sunday
bringing a chance of rain and snow to extreme eastern Washington
and the Idaho Panhandle. Cooler temperatures will then prevail
from late Sunday and into early next week.
&&
.DISCUSSION...
Quick morning update based on recommendations of midnight shift
that a high pop low qpf forecast would be good way to steer the
forecast for this morning/today up north of I-90 for the most
part. Tapered down to sprinkles along the southern edges of it and
pretty much a dry forecast to the south of I-90 with the exception
of the light sprinkles mentioned for the Spokane and Coeur D`
Alene area. Some northern valley fog still lingering per webcams
but expecation is it will erode through the morning. /Pelatti
&&
.AVIATION...
12Z TAFS: Bands of thick mid and high clouds will pour into
the area today with areas of light rain or sprinkles impacting the
GEG-SFF-COE corridor this morning. The rain will not impede
visibilities much...however there is an area of IFR fog/stratus
teasing this area. Not sure how expansive it is...so not sure how
long it will persist. Chances are good that it will ease quicker
than yesterday with the warm front and associated precipitation slowly
moving toward the Canadian Border. However through
18z...confidence in timing the ins and outs of fog will be quite
difficult. Other sites have a much easier forecast with variable
amounts of high and mid level clouds. These clouds should clear
from south to north through tonight. Whether or not this allows
IFR fog/cigs to reform tonight is questionable but some of the MOS
guidance is hinting at it. The clearer the skies are going into
the evening...the better the chances of fog reforming overnight.
fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 52 37 55 39 52 34 / 10 10 0 40 30 10
Coeur d`Alene 51 36 53 39 50 33 / 10 10 0 30 50 10
Pullman 56 41 58 42 52 36 / 10 0 0 10 20 10
Lewiston 60 41 62 45 57 38 / 0 0 0 10 10 0
Colville 49 36 53 38 53 33 / 50 20 0 40 30 10
Sandpoint 46 34 52 35 47 33 / 40 10 0 20 40 10
Kellogg 49 37 52 40 45 34 / 10 10 0 10 50 20
Moses Lake 54 37 54 40 57 36 / 0 0 0 10 10 0
Wenatchee 53 38 51 39 55 36 / 0 0 0 10 10 0
Omak 50 37 50 39 53 34 / 20 10 0 20 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
837 AM PST THU FEB 12 2015
.SYNOPSIS...
A weak warm front will cross the area today bringing light rain
or sprinkles to portions of the Inland Northwest. The greatest
threat of measurable rain will impact locations near the Cascades
and Canadian border. Otherwise look for the warm temperatures to
continue with a few record highs possible on Friday and Saturday.
A weak cold front will move through the region on Saturday
bringing a good chance of precipitation for most locations. An
even stronger cold front will push through the area on Sunday
bringing a chance of rain and snow to extreme eastern Washington
and the Idaho Panhandle. Cooler temperatures will then prevail
from late Sunday and into early next week.
&&
.DISCUSSION...
Quick morning update based on recommendations of midnight shift
that a high pop low qpf forecast would be good way to steer the
forecast for this morning/today up north of I-90 for the most
part. Tapered down to sprinkles along the southern edges of it and
pretty much a dry forecast to the south of I-90 with the exception
of the light sprinkles mentioned for the Spokane and Coeur D`
Alene area. Some northern valley fog still lingering per webcams
but expecation is it will erode through the morning. /Pelatti
&&
.AVIATION...
12Z TAFS: Bands of thick mid and high clouds will pour into
the area today with areas of light rain or sprinkles impacting the
GEG-SFF-COE corridor this morning. The rain will not impede
visibilities much...however there is an area of IFR fog/stratus
teasing this area. Not sure how expansive it is...so not sure how
long it will persist. Chances are good that it will ease quicker
than yesterday with the warm front and associated precipitation slowly
moving toward the Canadian Border. However through
18z...confidence in timing the ins and outs of fog will be quite
difficult. Other sites have a much easier forecast with variable
amounts of high and mid level clouds. These clouds should clear
from south to north through tonight. Whether or not this allows
IFR fog/cigs to reform tonight is questionable but some of the MOS
guidance is hinting at it. The clearer the skies are going into
the evening...the better the chances of fog reforming overnight.
fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 52 37 55 39 52 34 / 10 10 0 40 30 10
Coeur d`Alene 51 36 53 39 50 33 / 10 10 0 30 50 10
Pullman 56 41 58 42 52 36 / 10 0 0 10 20 10
Lewiston 60 41 62 45 57 38 / 0 0 0 10 10 0
Colville 49 36 53 38 53 33 / 50 20 0 40 30 10
Sandpoint 46 34 52 35 47 33 / 40 10 0 20 40 10
Kellogg 49 37 52 40 45 34 / 10 10 0 10 50 20
Moses Lake 54 37 54 40 57 36 / 0 0 0 10 10 0
Wenatchee 53 38 51 39 55 36 / 0 0 0 10 10 0
Omak 50 37 50 39 53 34 / 20 10 0 20 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
433 AM PST THU FEB 12 2015
.SYNOPSIS...
A weak warm front will cross the area today bringing light rain
or sprinkles to portions of the Inland Northwest. The greatest
threat of measurable rain will impact locations near the Cascades
and Canadian border. Otherwise look for the warm temperatures to
continue with a few record highs possible on Friday and Saturday.
A weak cold front will move through the region on Saturday
bringing a good chance of precipitation for most locations. An
even stronger cold front will push through the area on Sunday
bringing a chance of rain and snow to extreme eastern Washington
and the Idaho Panhandle. Cooler temperatures will then prevail
from late Sunday and into early next week.
&&
.DISCUSSION...
Today and Tonight...The strong upper level ridge will continue to
amplify over the Inland Northwest today. Despite its growing
presence there will be some minor weather issues to contend with
namely in response to plume of moisture rounding its western
flank. The latest radar mosaic was showing a plume of light
precipitation extending from the Olympic Peninsula southeast into
the Lewiston area. Thus far precipitation east of the Cascades has
been rather limited however there was a brief sprinkle noted at
Pullman earlier this morning. This feature is likely a weak warm
front and should drift slowly northward through the day. As it
nudges toward the Canadian border we expect the precipitation
chances will increase . This is due to a strengthening of the
isentropic ascent focused over the northern third of the forecast
area combined with growing orographic lift associated with the
south-southwest winds through the 850-700 mb layer. The biggest
question is will the precipitation be measurable. For most of the
Columbia Basin...Spokane/CdA area...and Wenatchee area we suspect
the answer is no. Sprinkles will be possible this morning...but
not much more. Farther north the odds for measurable rain look
much better. Pops have been raised but perhaps may need to be
boosted even more. The HRRR model is downplaying the chances for
precipitation for all locations except along the Canadian
border...but then again its not exactly nailing the current
situation. Nonetheless its a rather minor event with snow levels
remaining above all but the highest mountains and any
precipitation which falls will likely be less than a tenth of an
inch. The abundance of high and mid level clouds associated with
this front should minimize the fog coverage this morning at least
compared to yesterday morning but we still expect to see some
develop later this morning. For tonight the warm front is expected
to lift north of the Canadian border as a weak shortwave,
currently near 44n/132w, rounds the top of the ridge. The only
location which could still see some light precipitation tonight
will be near the Cascades as the shortwave tracks brushes through
that area. Mid and high level clouds will then decrease overnight
leading to a better chance of fog by morning. Temperatures will
continue their string of significantly warmer than normal
readings. Highs today will generally range from the mid 40s to the
50s...or generally around 10 degrees above normal. fx
Friday through Saturday: The upper level ridge remains in place
one more day before big changes are on the way. The 850 mb
temperatures are quite warm, and models are showing a surge of
drier air punching into southern and central WA during the
afternoon. This should provide enough clearing to allow surface
temperatures to warm quite nicely. Temperatures will range from
10 to more than 15 degrees above average for this time of the
year. Record high temperatures are possible across most of the
valleys of eastern WA and north ID. Friday night clouds will
increase ahead of the next weak weather feature. This will keep
temperatures pretty warm. Models have sped up the timing of the
next feature a bit. Have increased chance of precipitation late
Friday night into Saturday morning for most of northern WA...and
as far south as Spokane County. This wave will move through early
in the day and by the afternoon the rain showers should be mostly
confined to north ID. In addition, drier air moves in as well, as
there is slightly better mixing and winds as well temperatures
will once again approach near record highs for portions of central
WA.
Sunday through Thursday: Sunday the ridge begins to amplify off
the west coast and the Pac NW get under a more northwesterly flow.
This will usher in colder temperatures and a chance of mountain
snow across northeast WA and north ID Sunday and Monday. By Sunday
night drier air once again moves in, so colder nights are expected
with Wednesday night expected to be the coldest, but even at that,
it is only a few degrees below average for this time of the year.
By Thursday we start to moderate our temperatures but our forecast
will remain dry. /Nisbet
&&
.AVIATION...
12Z TAFS: Bands of thick mid and high clouds will pour into
the area today with areas of light rain or sprinkles impacting the
GEG-SFF-COE corridor this morning. The rain will not impede
visibilities much...however there is an area of IFR fog/stratus
teasing this area. Not sure how expansive it is...so not sure how
long it will persist. Chances are good that it will ease quicker
than yesterday with the warm front and associated precipitation slowly
moving toward the Canadian Border. However through
18z...confidence in timing the ins and outs of fog will be quite
difficult. Other sites have a much easier forecast with variable
amounts of high and mid level clouds. These clouds should clear
from south to north through tonight. Whether or not this allows
IFR fog/cigs to reform tonight is questionable but some of the MOS
guidance is hinting at it. The clearer the skies are going into
the evening...the better the chances of fog reforming overnight.
fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 52 37 55 39 52 34 / 10 10 0 40 30 10
Coeur d`Alene 51 36 53 39 50 33 / 10 10 0 30 50 10
Pullman 56 41 58 42 52 36 / 0 0 0 10 20 10
Lewiston 60 41 62 45 57 38 / 0 0 0 10 10 0
Colville 49 36 53 38 53 33 / 30 10 0 40 30 10
Sandpoint 46 34 52 35 47 33 / 30 10 0 20 40 10
Kellogg 49 37 52 40 45 34 / 10 10 0 10 50 20
Moses Lake 54 37 54 40 57 36 / 0 0 0 10 10 0
Wenatchee 53 38 51 39 55 36 / 0 0 0 10 10 0
Omak 50 37 50 39 53 34 / 20 10 0 20 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
ISSUED BY NATIONAL WEATHER SERVICE MARQUETTE MI
346 PM CST THU FEB 12 2015
.SYNOPSIS...ISSUED AT 239 PM CST THU FEB 12 2015
WATER VAPOR LOOP AND RUC ANALYSIS REVEALS AMPLIFIED PATTERN
FEATURING WEST COAST RIDGE AND BROAD UPSTREAM TROF ACROSS MUCH OF
NORTH AMERICA. MODELS INDICATE THIS PATTERN WILL STAY IN PLACE OVER
MUCH OF NEXT WEEK ALLOWING FOR PERIODIC SURGES OF ARCTIC AIR INTO
THE REGION RESULTING IN BLO NORMAL TEMPS. MODELS ADVERTISE ONLY
PERIODIC LIGHT PCPN WITH A FEW CLIPPER SHORTWAVES TRAVERSING AREA.
&&
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 239 PM CST THU FEB 12 2015
MINS TEMP FCST TONIGHT COULD BE TRICKY AS WINDS WILL DIE OFF WITH
SFC RDG MOVING ACROSS THE AREA. ALSO WAA MID-HIGH CLOUDS WILL BE
SPREADING INTO THE AREA AHEAD OF SHORTWAVE AND ASSOC SFC LOW DIVING
DOWN FM CENTRAL CANADA. THESE CLOUDS DEPENDING ON HOW THICK THEY ARE
MAY TEMPER RADIATIONAL COOLING UNDER LIGHT WIND REGIME. GIVEN
UNCERTAINTY WITH CLOUD THICKNESS DECIDED TO USED A BLEND OF COLDER
BASE REG GEM/ECMWF TEMPS AND MOS GUIDE TEMPS WHICH WAS CLOSE TO PREV
FCST AND IN MEDIUM RANGE OF TEMP GUIDANCE.
BACKED OFF SLIGHTLY ON POPS FOR FRI AS MODELS INDICATE BEST MOISTURE
AND ISENTROPIC ASCENT STAYING GENERALLY NORTH OF WI CLOSER TO TRACK
OF SHORTWAVE AND ASSOC SFC LOW. HAVE POPS RANGING FROM HIGH CHC
(AROUND 50 PCT) NORTH TO LOWER CHC 30-40 POPS FOR SOUTHERN PORTIONS
OF CWA. WAA WL HELP TEMPS RECOVER TO AROUND 20F...BUT MAX TEMPS
PROBABLY WON/T OCCUR UNTIL LATE IN THE DAY SO ADJUSTED DIURNAL CURVE
ACCORDINGLY.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 233 PM CST THU FEB 12 2015
N-NW WINDS WILL BE ON THE INCREASE LATE FRIDAY NIGHT INTO SATURDAY
THANKS TO THE INCREASING PRESSURE GRADIENT BETWEEN THE EXITING SFC
LOW SHIFTING FROM JUST E OF LAKE SUPERIOR AT 00Z SATURDAY TO THE
LOWER GREAT LAKES SATURDAY AFTERNOON...AND THE COLD ARCTIC HIGH
SINKING ACROSS S CENTRAL CANADA AND INTO THE N PLAINS. WHILE THE
COLDEST AIR WILL REMAIN N-NE OF WI...STILL EXPECT 850MB TEMPS TO
BOTTOM OUT AROUND -27 TO -30C SATURDAY AFTERNOON. AS A
RESULT...STEADY TO FALLING TEMPERATRUES WILL BE COMMON SATURDAY AS
THIS COLDER AIR RUSHES IN. HIGHS SATURDAY MAY ONLY ONLY TOP OUT IN
THE -3 TO 7F RANGE /COLDEST NE/.
KEPT THE POTENTIAL FOR BLOWING SNOW WHERE POPS WERE OVER 14
PERCENT...AND WIND GUSTS WERE OVER 20KTS. THE BEST CHANCE OF SNOW
WILL BE OVER THE N ANE E TIER COUNTIES AS LAKE EFFECT ON STRONG
WINDS BLOW WELL INLAND AND INTO N WI.
UNDER A CLEARING SKY SATURDAY NIGHT...AND WITH WINDS OF 5-10KTS OUT
OF THE N-NNW...WIND CHILL READINGS OF 25 TO 30 BELOW ZERO WILL BE
POSSIBLE. LOOK FOR LATER UPDATES AND FORECASTS ON THIS ARCTIC
AIRMASS AND LOW WIND CHILLS.
GENEARALLY FOLLOWED A MODEL BLEND FOR MUCH OF THIS PERIOD. NO
SIGNIFICANT STORMS ANTICIPATED...BUT WITH COLD WEATHER CONTINUING.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1205 PM CST THU FEB 12 2015
EXPECT VFR CONDITIONS THROUGH TONIGHT FOR ALL TAF SITES UNDER
BUILDING HIGH PRESSURE. WARM ADVECTION/LIFT AHEAD OF THE NEXT LOW
PRES SYSTEM DESCENDING FM ONTARIO WILL THEN BRING IN SOME LIGHT
SNOW LATE FRI MORNING/AFTERNOON AS CONDITIONS LOWER TO MVFR. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......VOSS
SHORT TERM.....VOSS
LONG TERM......KF
AVIATION.......VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1011 AM CST THU FEB 12 2015
.UPDATE...
MOSTLY SUNNY SKIES WILL PREVAIL WITH SOME CIRRUS MOVING OVERHEAD
LATER THIS AFTERNOON. NORTHWEST WINDS WILL WEAKEN AS HIGH PRESSURE
PUSHES INTO THE REGION AND MOVES OVERHEAD TONIGHT. LIGHT SNOW IS
EXPECTED TO MOVE ACROSS SOUTHERN WI FROM LATE MORNING THROUGH THE
AFTERNOON. ACCUMULATIONS LOOK TO BE A FEW TENTHS OF AN INCH.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS EXPECTED THROUGH EARLY FRIDAY. NORTHWEST WINDS WILL
WEAKEN THROUGH THE DAY AND BECOME LIGHT OVERNIGHT AS HIGH PRESSURE
MOVES OVERHEAD. WINDS WILL PICK UP SLIGHTLY AND BECOME SOUTHWESTERLY
FRIDAY. LIGHT SNOW IS EXPECTED TO MOVE ACROSS SOUTHERN WI FROM LATE
MORNING THROUGH THE AFTERNOON. ACCUMULATIONS LOOK TO BE A FEW TENTHS
OF AN INCH.
&&
.MARINE...
PRESSURE GRADIENT GRADUALLY WEAKENING AS HIGH PRESSURE IN
THE NORTHERN PLAINS EDGES CLOSER TO LAKE MICHIGAN. NORTHWEST WIND
GUSTS HAVE NOT BEEN REACHING GALE CRITERIA FOR SEVERAL HOURS AT
LAKESHORE STATIONS AND RUC SOUNDINGS OVER THE NEARSHORE WATERS
INDICATING WIND GUSTS RAPIDLY DIMINISHING TODAY. HENCE DOWNGRADED
GALE WARNING TO SMALL CRAFT ADVISORY BUT LEFT HEAVY FREEZING SPRAY
WARNING RUNNING UNTIL 18Z. KEPT SMALL CRAFT ADVY GOING UNTIL 00Z/13
HOWEVER AS WAVE HEIGHTS IN ICE FREE AREAS WILL BE SLOWER TO DECREASE
BELOW 5 FEET.
MBK
&&
.PREV DISCUSSION... /ISSUED 343 AM CST THU FEB 12 2015/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.
SNOW SHOWERS ARE QUICKLY MOVE SEWD OUT OF SE WI WITH CLEARING SKIES
BEHIND. STRONG SUBSIDENCE VIA COLD ADVECTION AND DAVA IN THE WAKE OF
THE UPPER TROUGH WILL MAINTAIN MO CLEAR TO PTLY CLOUDY SKIES TODAY.
THE BRISK NNWLY WINDS WILL GRADUALLY SUBSIDE THROUGH THE AFTERNOON
AS THE ARCTIC HIGH APPROACHES. TEMPS WILL WARM TO AROUND 10F WITH
THE TEENS BELOW ZERO FOR THE MORNING HOURS. FOR TNT...THE RIDGE AXIS
OF THE ARCTIC HIGH WILL SHIFT EWD ACROSS THE STATE WITH LGT SWLY
WINDS DEVELOPING LATE ALONG WITH AN INCREASE IN MID TO HIGH CLOUDS
VIA WARM ADVECTION. BEFORE THEN...TEMPS WILL LIKELY FALL BELOW ZERO
FOR MOST AREAS.
FRIDAY AND FRIDAY NIGHT - CONFIDENCE...MEDIUM
GRADUAL ISENTROPIC ASCENT COMBINED WITH A SHORTWAVE RIDING IN
FROM THE NORTHWEST WILL RESULT IN A PERIOD OF LIGHT SNOW ACROSS
SOUTHERN WISCONSIN. THE MODELS ARE TRENDING DRIER WITH RESPECT TO
QPF. BUT STILL LOOKING AT UP TO A 1/2 INCH OR SO OF SNOW
ACCUMULATION. THE MODELS SHOOT ANOTHER WEAK WAVE THROUGH THE FLOW
BUT FOR THE MOST PART THIS FEATURE MISSES US TO THE SOUTHWEST AS
ENERGY FROM SIGGY VORTEX CRASHES INTO WI LATER IN THE NIGHT.
STRONG 925/850 COLD ADVECTION NOTED AFTER 6Z. NO LAKE COMPONENT
THOUGH WILL KEEP SOME FLURRIES OR SMALL POPS GOING TO ACCOUNT FOR
INCREASING UPPER DYNAMICS AND THE PASSING WAVE TO THE SOUTHWEST.
BUT MAIN STORY WILL BE THE INCREASING NW WINDS AND RAMP UP OF THE
COLD ADVECTION.
SATURDAY AND SUNDAY - CONFIDENCE...MEDIUM
BRUTALLY COLD WEEKEND SHAPING UP WITH CORE OF ARCTIC AIR
ENTRENCHED ACROSS THE AREA. 925 TEMPS DOWN TO THE -20 TO -24C
RANGE WITH NORTH WINDS A BIG FACTOR RIGHT INTO SATURDAY NIGHT. A
WIND CHILL ADVISORY WILL LIKELY BE NEEDED SATURDAY NIGHT INTO
SUNDAY MORNING...HOWEVER WINDS ARE EXPECTED TO EASE ON SUNDAY AS
CORE OF HIGH PRESSURE SETTLES ACROSS THE STATE RESULTING IN A
SLACKENED PRESSURE GRADIENT. LAKE EFFECT POTENTIAL LOOKS LOW AT
THIS TIME. MODELS ALL KEEPING PRECIP OFFSHORE. TRAJECTORIES DUE
GET BORDERLINE FOR MKE CNTY SOUTHWARD THOUGH SOUNDINGS LOOK RATHER
DRY WITH FAIRLY LOW INVERSION HEIGHTS.
MONDAY THROUGH WEDNESDAY - CONFIDENCE...MEDIUM
WAS TEMPTED TO PULL POPS COMPLETELY AS BOTH GFS AND ECMWF SHOW
SYSTEM STAYING WELL SOUTH OF WI. HOWEVER SOME HINTS OF SOME WAA
PRECIP...ESP ON THE GEM...AND THE GEM IS ALSO A BIT MORE OF A
CLOSE CALL WITH THE NORTHERN FRINGE OF THE PRECIP SHIELD WITH THE
SOUTHERN LOW. SO AT THIS TIME WILL LEAVE THE FAIRLY SMALL
SUPERBLEND POPS IN PLACE. A RENEWED THERMAL RIDGE BRINGS 925 TEMPS
BACK TO AROUND -10C FOR MONDAY NIGHT BEFORE NEXT BLAST OF ARCTIC
AIR ARRIVES IN EARNEST TUESDAY INTO WEDNESDAY.
AVIATION/12Z TAFS/...BRISK NWLY WINDS WILL SUBSIDE DURING THE
AFTERNOON AND BECOME LIGHT TNT AS POLAR HIGH PRESSURE MOVES
OVERHEAD. MO CLEAR TO PTLY CLOUDY SKIES WILL PREVAIL TODAY AND TNT
WITH VFR CONDITIONS.
MARINE...A GALE WARNING AND HEAVY FREEZING SPRAY WARNING CONTINUES
UNTIL NOON TODAY. THE BRISK NNWLY WILL GRADUALLY SUBSIDE FROM LATE
THIS MORNING INTO THE AFTERNOON BUT HIGH WAVES IN ICE FREE AREAS
WILL LINGER INTO THE AFTERNOON. DUE TO THE LINGERING HIGH WAVES...A
SMALL CRAFT ADVISORY MAY BE NEEDED FOR THE AFTERNOON. ANOTHER PERIOD
OF BRISK NWLY WINDS AND HIGH WAVES DUE TO ANOTHER ARCTIC FRONT WILL
BE FROM FRI NT INTO SAT EVENING. A SMALL CRAFT ADVISORY WILL LIKELY
BE NEEDED. WIND GUSTS COULD APPROACH GALE FORCE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...HEAVY FREEZING SPRAY WARNING UNTIL NOON CST TODAY FOR LMZ643>646.
SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...MARQUARDT
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
FRIDAY THROUGH WEDNESDAY...COLLAR
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
325 AM MST THU FEB 12 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM MST THU FEB 12 2015
WEATHER EXPECTED TO BE PRETTY QUIET THIS PERIOD WITH TEMPERATURES
REMAINING MILD ACROSS THE CWA TODAY THROUGH FRIDAY. NWLY FLOW
ALOFT THROUGH FRIDAY WILL BRING VARYING AMOUNTS OF MAINLY HIGH
CLOUDS WITH ONE DECENT SIZED AREA NOW MOVING SSE ACROSS THE
WESTERN DAKOTAS INTO NW NEBRASKA. IN ADDITION SOME LOW CLOUDS NOW
OVER THE PANHANDLE IN A WEAK UPSLOPE FLOW REGIME ON THE WESTERN
PERIPHERY OF A COOL SFC HIGH MOVING SSE OVER THE NORTHERN PLAINS.
THIS HAS HELPED TO KEEP TEMPS UP A BIT AND HOLD OFF ANY FOG
FORMATION THUS HAVE REMOVED THE MENTION OF PATCHY FREEZING DRIZZLE
THERE FOR THIS MORNING. SHOULD SEE A DECREASE IN CLOUDS ACROSS
THE REGION THIS AFTERNOON AND EVENING AS THE LATEST SURGE OF HIGH
LEVEL MOISTURE DROPS FARTHER SE AND OUT OF THE AREA AND THE COOLER
AIR OVER THE PLAINS SHIFTS EASTWARD. LEE TROFFING DEVELOPING OVER
THE HIGH PLAINS TODAY WILL INCREASE THE SFC PRESSURE GRADIENT
ACROSS SE WY AND RESULT IN SOME GUSTY WINDS AROUND THE MTNS BUT
NOT LOOKING TOO STRONG.
NEXT SURGE OF COOLER AIR WILL MOVE SOUTH OUT OF CENTRAL CANADA
FRIDAY NIGHT AND INTO THE NORTHERN AND CENTRAL PLAINS SATURDAY.
SOME OF THIS COOLER AIR WILL BACK WESTWARD ACROSS THE NEBRASKA
PANHANDLE AND POSSIBLY FAR EASTERN WY SAT MORNING INTO THE
AFTERNOON. THIS WILL MAKE MAX TEMPS OVER THAT AREA A BIT TRICKY
SATURDAY DEPENDING ON HOW FAR AND STRONG THE COOLER AIR SURGE
TURNS OUT IN THAT AREA AND HOW MUCH ASSOCIATED CLOUD COVER
ACCOMPANIES IT. REMAINING DRY OTHERWISE
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 AM MST THU FEB 12 2015
THE RECENT UNSEASONABLE WARMTH WILL COME TO AN ABRUPT END EARLY
NEXT WEEK AS A MAJOR PATTERN SHIFT BRINGS A RETURN TO WINTRY
CONDITIONS. BEFORE THEN...RELATIVELY DRY NORTHWEST FLOW WILL
YIELD ONE MORE DAY OF GENERALLY BENIGN CONDITIONS SUNDAY. THE
WARM PREFRONTAL AIR MASS WILL BOOST HIGHS INTO THE MID 40S MOST
LOCATIONS. THE WRITING WILL BE ON THE WALL BY SUNDAY THO...AS
RIDGE AMPLIFICATION OVER THE ERN PACIFIC SENDS A 140KT POLAR JET
PLUNGING INTO WRN NOAM. STRONG SHORTWAVE ENERGY ON THE NOSE OF THE
POLAR JET WILL DIVE SOUTHEAST TOWARDS UTAH/SW WYOMING BY SUNRISE
MONDAY. AT THE SFC...THE REFLECTED PRESSURE FALLS AHEAD OF THE
SYSTEM WILL SEND A STRONG COLD FROPA THRU THE CWA SUNDAY NT. WINDS
WILL TURN NNE IN ITS WAKE AND COMBINE WITH FAVORABLE POSITIONING
OF THE NOSE OF THE POLAR JET TO PRODUCE WIDESPREAD ACCUMULATING
SNOW BEGINNING SUNDAY NT AND CONTINUING THROUGH MONDAY NT. AS CAN
BE EXPECTED...TIMING AND RESIDENCE TIME DIFFERENCES EXIST IN THE
MEDIUM RANGE MODELS WITH THE ECMWF IMPACTING THE REGION THE
EARLIEST AND LINGERING SNOW THE LONGEST EVEN INTO TUESDAY.
REGARDLESS OF THE EVENTUAL MODEL VICTOR CONFIDENCE IS INCREASING
OF THIS WINTRY OUTCOME. HAVE CONTINUED THE TREND OF PUSHING SNOW
CHANCES UP...NOW INTO LIKELY CATEGORY MOST AREAS FOR SUNDAY
NT...MONDAY AND MONDAY NT. GUSTY NORTHEAST WIND WILL ACCOMPANY THE
SNOW AS WELL ESPECIALLY DURING DAYLIGHT HOURS ON MONDAY. GFS PROGS
SUGGEST 30-35 KNOTS AT THE TOP OF THE MIXED LAYER MAY BE ABLE TO
SFC. HAVE ADDED AREAS OF BLOWING SNOW TO THE SE WY PORTION OF THE
AREA MONDAY AFTERNOON. IF CURRENT PROGS HOLD...THE COMBINATION OF
ACCUMULATING SNOW AND GUSTY WINDS COULD HAVE HEFTY IMPACTS ON AREA
TRAVEL SUNDAY NT THRU EARLY TUESDAY. STAY TUNED. THE OTHER STORY
WILL BE THE ACCOMPANYING FRIGID TEMPS. HIGHS MONDAY WILL ONLY
REACH THE 20S...WITH SINGLE DIGITS/LOW TEENS EXPECTED FOR TUESDAY.
MODELS SUGGEST SOME TEMPERATURE MODERATION FOR WED- THU...THOUGH
WITH THE EXPECTED SNOWPACK IN PLACE...IT WILL LIKELY BE SLOWER
THAN CURRENTLY PROGD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 953 PM MST WED FEB 11 2015
LATEST HRRR GUIDANCE USED FOR THE 06Z TAF PACKAGE. SHOWING A BAND
OF LOW CLOUDS MOVING INTO THE PANHANDLE THROUGH THE OVERNIGHT
HOURS. CAN SEE THE LOW CLOUDS ON THE 11-3.9U SATELLITE
IMAGERY...THOUGH IT DOES LOOK LIKE MOST OF THE LOW CLOUDS WILL
STAY EAST. VFR CONDITIONS BY MID MORNING FOR ALL LOCATIONS WITH
GUSTY WEST WINDS.
&&
.FIRE WEATHER...
ISSUED AT 325 AM MST THU FEB 12 2015
NO SIGNIFICANT CONCERNS ANTICIPATED THROUGH THE WEEKEND WITH
WEATHER FACTORS REMAINING MOSTLY NON-CRITICAL. SOME LOCALLY GUSTY
WINDS AROUND THE SE WY MTNS TODAY. COLDER CONDITIONS LOOK TO
ARRIVE BY MONDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RE
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1000 PM MST WED FEB 11 2015
.SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 220 PM MST WED FEB 11 2015
OVERALL A QUIET FORECAST PERIOD. CLOUDS ARE STARTING TO THIN ACROSS
MUCH OF THE AREA AS UPPER RIDGING BUILDS INTO THE REGION. PLENTY OF
LOW TO MID LEVEL MOISTURE IS STILL PRESENT TO OUR NORTH AND EAST AS
EVIDENCED BY WIDESPREAD CLOUDS OVER THE DAKOTAS ON AFTERNOON VISIBLE
SATELLITE IMAGERY. THE LATEST NAM BRINGS CONSIDERABLE BOUNDARY LAYER
MOISTURE SOUTHWESTWARD INTO THE CWA LATE TONIGHT. FORECAST SOUNDINGS
SHOW A 3000 TO 5000 FT DEPTH OF SATURATION OVER EAST CENTRAL WY INTO
THE NORTHERN PANHANDLE AFTER 06Z THU...SO BELIEVE WE COULD SEE SOME
PATCHY FOG EVEN THOUGH WIND DIRECTIONS DO NOT APPEAR TO BE FAVORABLE
FOR VERY LOW CIGS. ALL OF THIS SATURATION SHOULD BE WARMER THAN -10C
GIVEN THERMAL PROFILES...AND WITH SUB- FREEZING SURFACE TEMPERATURES
WE CANNOT ENTIRELY RULE OUT SOME FREEZING DRIZZLE. NOT EXPECTING TO
SEE ANYTHING MEASURABLE...SO POPS REMAIN NIL.
WARMER FOR THU AS LOW-LEVEL DOWNSLOPE FLOW RETURNS TO AREAS EAST OF
THE LARAMIE RANGE. LATEST MOS GUIDANCE HINTS AT HIGHS APPROACHING 60
F OVER THE PANHANDLE...BUT THIS COULD BE TEMPERED BY THICK CIRRUS AS
THE MODELS AGREE ON HIGH H5-H3 RH VALUES WITH A STRONG H25 JET JUST
TO OUR NORTHEAST. GENERALLY STAYED IN THE 50S. WINDS COULD BE A BIT
OF AN ISSUE AROUND 12Z THU. THE H85 CAG-CPR GRADIENT PEAKS AROUND 50
METERS AT THAT TIME AND THE NAM SUGGESTS AROUND 45 KTS AT H75. MAIN
LIMITING FACTOR WILL BE OVERALL WEAK SUBSIDENCE AND THE SHORT LIVED
NATURE OF THE STRONGER GRADIENT...SO KEPT THE FORECAST BELOW WARNING
CRITERIA FOR THE ARLINGTON GAP. BORDEAUX SHOULD SEE AN INCREASE IN
WINDS DURING THE LATE MORNING AND AFTERNOON AS THE STRONGEST SURFACE
PRESSURE FALLS SPREAD ACROSS SOUTH CENTRAL SD AND STRENGTHEN WEST TO
EAST ORIENTED LOW-LEVEL GRADIENTS. MIXING WILL BE STRONGER THEN AS
WELL...BUT FLOW ALOFT WILL BE ON THE DOWNTREND. GUSTS SHOULD PEAK IN
THE 50-55 MPH RANGE...SO DO NOT THINK A WATCH IS NEEDED. DRY NW FLOW
ALOFT CONTINUES INTO FRI ON THE EAST SIDE OF THE RIDGE. TEMPERATURES
WILL BE SIMILAR TO THU WITH H7 TEMPS STAYING BETWEEN -1 AND -4 DEG C
ACROSS THE AREA.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 250 PM MST WED FEB 11 2015
12Z MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT PROGGING THE UPPER RIDGE
PATTERN TO DEAMPLIFY AS TROUGHING TAKES SHAPE OVER THE NORTHERN ROCKIES.
THIS TROUGH WILL MOVE ACROSS THE FORECAST AREA LATE SATURDAY. A LEE
SIDE TROUGH TO TAKE SHAPE OVER THE EASTERN PLAINS OF WY/CO SATURDAY
AND SHIFTS EAST INTO WESTERN NE BY SUNDAY. SATURDAY WILL BE THE LAST
OF A LONG STRETCH OF MILD AND DRY DAYS WITH HIGHS IN THE 40S AND 50S
AS A MAJOR UPPER LEVEL PATTERN SHIFT TAKE PLACE LATE IN THE WEEKEND
AND INTO EARLY NEXT WEEK. SHORTWAVE ENERGY MOVES ONSHORE FROM THE
PACIFIC NORTHWEST AND CAUSES A AMPLIFICATION OF THE TROUGH OVER
THE GREAT BASIN AND ROCKIES MONDAY AND TUESDAY. THIS WILL OPEN THE
DOOR FOR ARCTIC AIR TO PLUNGE SOUTHWARD INTO THE REGION. A SURFACE
LOW DEVELOPS OVER EASTERN UT/WESTERN CO SUNDAY NIGHT AND TRACKS
SOUTHEAST TO THE VICINITY OF THE TX/OK PANHANDLES BY LATE MONDAY.
NORTH TO NORTHEAST FLOW LOW LEVEL FLOW...ABUNDANT MOISTURE AND
LIFT IN LEFT FRONT QUADRANT OF UPPER JET WILL SET THE STAGE FOR
WIDESPREAD WINTRY PRECIPITATION A GOOD BET SUNDAY NIGHT THROUGH
MONDAY NIGHT. TOO EARLY TO PREDICT SNOW ACCUMULATIONS...BUT
CONFIDENCE IS INCREASING THAT MUCH OF THE FORECAST AREA WILL SEE
SOME MEASURABLE SNOWFALL. GUSTY NORTHEASTERLY WINDS WILL RESULT IN
BLOWING/DRIFTING SNOW.
HIGH TEMPERATURES SUNDAY WILL BE ABOUT 10 DEGREES COOLER THAN
SATURDAY WITH 30S AND 40S. THE IMPACT OF THE ARCTIC AIR MASS WILL
BEGIN TO BE REALIZED MONDAY WITH HIGHS IN THE TEENS AND 20S. SINGLE
DIGITS AND TEENS ARE FORECAST FOR HIGH TEMPERATURES TUESDAY. LOWS
WILL DIP INTO THE SINGLE DIGITS MONDAY NIGHT...WITH SOME SINGLE
DIGITS BELOW ZERO POSSIBLE TUESDAY NIGHT. FORTUNATELY...WINDS WILL
BE LIGHTER WITH WIND CHILLS IN THE TEENS BELOW ZERO. UPPER TROUGH
SHIFTS EAST WITH RISING LOW/MID LEVEL HEIGHTS/THICKNESSES
RESULTING IN MODERATING TEMPERATURES WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 953 PM MST WED FEB 11 2015
LATEST HRRR GUIDANCE USED FOR THE 06Z TAF PACKAGE. SHOWING A BAND
OF LOW CLOUDS MOVING INTO THE PANHANDLE THROUGH THE OVERNIGHT
HOURS. CAN SEE THE LOW CLOUDS ON THE 11-3.9U SATELLITE
IMAGERY...THOUGH IT DOES LOOK LIKE MOST OF THE LOW CLOUDS WILL
STAY EAST. VFR CONDITIONS BY MID MORNING FOR ALL LOCATIONS WITH
GUSTY WEST WINDS.
&&
.FIRE WEATHER...
ISSUED AT 220 PM MST WED FEB 11 2015
NEAR CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE OVER THE
SOUTHERN LARAMIE RANGE AND ADJACENT PLAINS/FOOTHILLS THU AFTERNOON.
GUSTY WESTERLY DOWNSLOPE WINDS WILL COMBINE WITH MINIMUM RH VALUES
BETWEEN 10 AND 15 PERCENT. FUELS ARE NOT FAVORABLE FOR LARGE FIRE
GROWTH AT THIS TIME. OTHERWISE MINIMAL FIRE WEATHER CONCERNS ARE
EXPECTED OVER THE DISTRICTS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...GCC
FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
337 AM CST SAT FEB 14 2015
.SHORT TERM...
332 AM CST
THROUGH SUNDAY...
NO CHANGES TO GOING HEADLINES FOR TODAY. HOWEVER...WE HAVE ISSUED A
WIND CHILL ADVISORY FOR THE AREA FOR TONIGHT.
MAIN WEATHER FORECAST CONCERNS CONTINUE TO FOCUS ON THE STRONG
ARCTIC PUSH TODAY...WITH DANGEROUS WIND CHILLS TONIGHT...AND ALSO
THE LAKE EFFECT SNOW SHOWERS...PARTICULARLY ACROSS NORTHWESTERN
INDIANA LATER TODAY AND TONIGHT...THEN OVER NORTHEASTERN ILLINOIS ON
SUNDAY.
WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS THE MAIN UPPER LEVEL PV
ANOMALY RAPIDLY DIGGING SOUTHWARD OVER NORTHERN WISCONSIN.
MEANWHILE...THE ASSOCIATED SURFACE LOW CONTINUES TO DEEPEN TO NEAR
1000 MB OVER THE UPPER GREAT LAKES REGION...WITH THE MAIN SURFACE
COLD FRONT RIGHT ON OUR DOOR STEP ACROSS FAR NORTHERN ILLINOIS.
TEMPERATURES AHEAD OF THIS FRONT AT STILL QUITE MILD IN THE UPPER
20S TO NEAR 30. HOWEVER...THE BOTTOM WILL FALL OUT IN A HURRY HERE
OVER THE NEXT FEW HOURS...AS TEMPERATURES QUICKLY TUMBLE INTO THE
TEENS AFTER DAYBREAK TODAY...AND CONTINUE TO FALL INTO THE SINGLE
DIGITS THIS AFTERNOON.
LOWER LEVEL LAPS RATES WILL STEEP UP FOLLOWING THE FRONTAL
PASSAGE...AND THIS SHOULD ALLOW FOR THE DEVELOPMENT OF SOME ISOLATED
TO SCATTERED SNOW SHOWERS ACROSS THE REGION THIS MORNING.
HOWEVER...IT APPEARS THE BETTER FOCUS FOR SNOW SHOWERS...OUTSIDE OF
LAKE EFFECT...WILL OCCUR ACROSS MY SOUTHERN AREAS THIS MORNING AS THE
LOWER LEVEL BAROCLINIC ZONE CONTINUES TO STRENGTHEN...SETTING UP A
BAND OF STRONG FGEN ACROSS CENTRAL ILLINOIS THIS MORNING. THIS WILL
BE A SHORT LIVED FEATURE...HOWEVER...SO SNOW AMOUNTS AREA-WIDE WILL
LIKELY REMAIN A HALF IN OR LESS.
NORTHERLY WINDS WILL INCREASE QUICKLY THIS MORNING...AND THE
COMBINATION OF VERY STRONG COLD AIR ADVECTION...AND RAPID PRESSURE
RISES...COULD RESULT IN A PERIOD OF NEAR WIND ADVISORY CRITERIA WINDS
(GUSTS TO 45 MPH)...PARTICULARLY ACROSS EASTERN ILLINOIS AND
NORTHWESTERN INDIANA LATER THIS MORNING AND INTO THE AFTERNOON.
MODEL SOUNDINGS ACROSS THESE AREAS INDICATE MEAN MIXING LAYER WINDS
AROUND 36 KT...WITH AROUND 40 TO 42 KT AT THE TOP OF MIXING LAYER.
STRONGLY FORCED COLD AIR ADVECTION REGIMES SUCH AS WHAT IS EXPECTED
THIS MORNING...CAN SET UP SITUATIONS WHEN SOME OF THE HIGHEST WINDS
IN THE MIXING LAYER MIX DOWN TO THE SURFACE AS WIND GUSTS...AT LEAST
FOR SHORT PERIODS OF TIME. IF THIS DOES OCCUR...THERE COULD BE A
SHORT PERIOD WITH WIND GUSTS TOPPING 45 MPH TODAY. OVERALL IT
APPEARS THE STRONGEST WIND POTENTIAL WILL BE NEAR THE LAKE IN
NORTHWESTERN INDIANA...AND THIS AREA IS CURRENTLY COVERED BY EITHER
A WIND ADVISORY OR A WINTER STORM WARNING. WE THOUGHT ABOUT POSSIBLY
EXPANDING THE WIND ADVISORY TO INCLUDE ALL OF NORTHWESTERN INDIANA
AND SOME OF EASTERN ILLINOIS. HOWEVER...AFTER COLLABORATING WITH
NEIGHBORING OFFICES...WE HAVE DECIDED NOT TO EXPAND THE CURRENT WIND
ADVISORY.
THE LAKE EFFECT POTENTIAL IS REALLY UNCHANGED FROM PREVIOUS
FORECASTS. IT STILL APPEARS THAT THE MAIN SETUP TODAY WILL FAVOR
NORTHEASTERN PORTER COUNTY INDIANA AND POINTS EAST...AS STRONG
NORTHWESTERN BOUNDARY LAYER WINDS KEEP THE BETTER LOWER LEVEL
CONVERGENCE MORE BROAD...AND MAINLY TO THE EAST OF MY AREA. THIS
COULD SUPPORT MULTIPLE BANDS OF LAKE EFFECT SNOW SHOWERS. HOWEVER...IT
STILL DOES APPEAR THAT AS A STOUT SURFACE BUILDS EASTWARD ACROSS THE
UPPER MIDWEST BY THIS EVENING...THAT THE BOUNDARY LAYER WINDS OVER
LAKE MICHIGAN WILL BECOME MORE NORTHERLY...AND GRADUALLY EASE IN
MAGNITUDE OVERNIGHT TONIGHT. THIS COULD SET UP MORE OF A SINGLE
CONVERGENT WESTWARD MOVING BAND OF LAKE EFFECT SNOW SHOWERS OVER
SOUTHERN LAKE MICHIGAN TONIGHT...AND BETTER ACCUMULATION POTENTIAL
FOR MY NORTHWESTERN INDIANA COUNTIES NEAR THE LAKE. INVERSION
HEIGHTS SHOULD BE ON A DECLINE DURING THIS TIME. HOWEVER...GIVEN THE
COLD AIRMASS...THE CLOUDS SHOULD BE COLD ENOUGH TO SUPPORT ICE
CRYSTALS. TOTAL SNOWFALL AMOUNTS SHOULD NOT GET TO OUT OF HAND...AS
THE BAND SHOULD BECOME PROGRESSIVE. HOWEVER...AMOUNTS IN EXCESS OF 6
INCHES ARE STILL POSSIBLE ACROSS PORTIONS OF THE WARNING AREA.
ADDITIONALLY...WITH THE STRONG WINDS TODAY AND THIS EVENING...BLOWING
SNOW AND WHITE OUT CONDITIONS WILL BE A CONCERN AT TIMES.
WINDS OVER THE LAKE WILL CONTINUE TO BACK MORE NORTHEASTERLY FOR A
PERIOD ON SUNDAY...SO SOME LIGHT LAKE EFFECT SNOW SHOWERS APPEAR
LIKELY ACROSS THE CHICAGO AREA OF NORTHEASTERN ILLINOIS.
HOWEVER...THE BAND OF SNOW SHOWERS LOOKS TO BECOME A LESS ORGANIZED
BY SUNDAY. THEREFORE...IT STILL APPEARS THAT ACCUMULATIONS ACROSS
THE CHICAGO AREA WILL GENERALLY REMAIN ON THE LIGHT SIDE. THE WINDS
ARE EXPECTED SHIFT OFFSHORE BY EARLY SUNDAY EVENING...SO ANY
LINGERING SHOWERS WILL END BY THIS TIME.
A WIND CHILL ADVISORY WILL GO INTO EFFECT FOR THE REGION THIS
EVENING. THE COMBINATION OF LINGERING BREEZY WINDS AND TEMPERATURES
FALLING INTO NEGATIVE TERRITORY THROUGH THE EVENING WILL SET UP WIND
CHILLS OF 20 BELOW TO 30 BELOW...WITH THE COLDEST EXPECTED ACROSS
NORTH CENTRAL ILLINOIS. THIS ADVISORY WILL BE IN EFFECT UNTIL MID
MORNING ON SUNDAY. TEMPERATURES LOOK TO ONLY TOP OUT NEAR 10 ABOVE IN
MOST AREAS ON SUNDAY...BUT WITH LIGHT WINDS DURING THE DAY...WIND
CHILLS SHOULD NOT BE AN ISSUE.
KJB
&&
.LONG TERM...
332 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
THE WEATHER PATTERN OVER THE COUNTRY WILL CONTINUE TO FAVOR
PERIODS OF COLD ARCTIC OUTBREAKS OVER THE EASTERN HALF OF THE
CONUS NEXT WEEK. STRONG HIGH LATITUDE UPPER RIDGING OVER THE EASTERN
PACIFIC/WESTERN NORTH AMERICA WILL SET THE STAGE FOR A FAIRLY
PROLONGED PERIOD OF MUCH BELOW NORMAL HEIGHTS AND TEMPERATURES
ACROSS MUCH OF EASTERN NORTH AMERICA. OUTSIDE OF LAKE EFFECT
SNOWS...NO BIG SNOW EVENTS ARE EXPECTED THROUGH THE PERIOD.
HOWEVER...SOME MINOR SNOW SYSTEMS COULD IMPACT THE AREA WITHIN THE
CYCLONIC UPPER LEVEL FLOW PATTERN. A REINFORCING SHOT OF COLD
ARCTIC AIR LOOKS TO SET UP OVER THE AREA BY MID WEEK...AND THIS
AIRMASS COULD EVEN BE A BIT COLDER THAN THE SHORT TERM COLD
EXPECTED. THIS COULD RESULT IN HIGH TEMPERATURES ONLY IN THE
SINGLE DIGITS IN MOST AREAS ON WEDNESDAY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MAINLY MVFR CIGS THROUGH EARLY AFTERNOON...WITH SOME BREAKS
POSSIBLE LATE TONIGHT.
* WINDS SHIFT NORTHWEST EARLY THIS MORNING AND INCREASE IN SPEED.
GUSTS TO AROUND 35 KT FROM MID MORNING THROUGH AT LEAST MID
AFTERNOON BEFORE GRADUALLY EASING.
* SCATTERED SNOW SHOWERS AND INTERMITTENT IFR VSBY POSSIBLE FROM
AROUND DAYBREAK THROUGH MID/LATE MORNING.
MDB
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE TO THE EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE
SOUTHEAST THROUGH THE DAY WHILE STRONG HIGH PRESSURE MOVES INTO
THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY. WEST-
SOUTHWEST WINDS CURRENTLY IN PLACE WILL TURN WEST-NORTHWEST THEN
NORTHWEST THROUGH DAYBREAK AS A COLD FRONT CROSSES THE AREA. THE
PRESSURE GRADIENT WILL STRENGTHEN AS THE HIGH BUILDS IN AND
COMBINE WITH A STRONG PUSH OF COLD AIR BRINGING GUSTY WINDS
THROUGH EARLY THIS EVENING. SPEEDS OF 20-25 KT ARE EXPECTED BY MID
MORNING WITH GUSTS INTO THE 30-35 KT RANGE...WITH SOME 35-40 KT
GUSTS POSSIBLE AT TIMES...ESPECIALLY AT GYY GIVEN THEIR PROXIMITY
TO THE LAKE. WINDS WILL EASE THIS EVENING.
CIGS HAVE SLOWLY BEEN LOWERING TO MVFR AND WILL CONTINUE TO LOWER
EARLY TONIGHT. SATELLITE SHOWS A CLEARING WEDGE ACROSS SOUTHEAST
MINNESOTA AND WEST-CENTRAL WISCONSIN WHICH IS WORKING SOUTHEAST
BUT STRATUS ACROSS NORTHERN WISCONSIN IS PUSHING SOUTHWARD AND
WILL LIKELY CLOSE THE GAP. WILL KEEP CIGS IN PLACE OVERNIGHT BUT
SOME SCATTERING IS POSSIBLE TOWARD 10Z OR SO FOR A FEW HOURS.
SNOW SHOWERS ARE EXPECTED TO DEVELOP BY AROUND DAYBREAK AS THE
COLD AIR PUSHES IN. COVERAGE IS SOMEWHAT QUESTIONABLE BUT DO
EXPECT ACTIVITY. WILL CONTINUE WITH A PERIOD OF IFR VSBY IN SHSN
BUT MAY BE ABLE TO ADJUST THIS WITH LATER UPDATES TO SHOW MORE
INTERMITTENT VSBY REDUCTION. CIGS ARE EXPECTED TO SCATTER/CLEAR
LATER THIS AFTERNOON WITH LITTLE IN THE WAY OF CLOUDS THIS
EVENING/TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN MVFR CIGS. MEDIUM CONFIDENCE IN TIME OF
SCATTERING THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS AND SEEING GUSTS AROUND 35 KT.
* MEDIUM-HIGH CONFIDENCE IN SHSN DEVELOPING THIS MORNING BUT LOW-
MEDIUM CONFIDENCE IN COVERAGE AND DURATION OF VSBY REDUCTION.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...LAKE EFFECT SNOW SHOWERS LIKELY WITH POTENTIAL IFR.
NORTHEAST WINDS.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO NORTHWEST
WINDS.
RATZER
&&
.MARINE...
317 AM CST
LOW PRESSURE JUST EAST OF LAKE SUPERIOR OR OVER NORTHERN GEORGIAN
BAY WILL MOVE SOUTHEAST TO THE SOUTHERN NEW ENGLAND COAST INTO
TONIGHT WHILE STRENGTHENING. VERY STRONG HIGH PRESSURE OVER THE
CANADIAN PRAIRIES WILL SETTLE SOUTHWARD INTO THE MID AND UPPER
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES INTO SUNDAY.
WINDS ARE SHIFTING FROM SOUTHWEST TO NORTHWEST AS A STRONG COLD
FRONT PUSHES SOUTHWARD DOWN THE LAKE THIS MORNING. WITH THE LOW
DEEPENING AND THE VERY STRONG HIGH ALLOWING FOR AN INCREASING
PRESSURE GRADIENT AND THEN COMBINING WITH THE STRONG COLD
ADVECTION BEHIND THE FRONT...WINDS WILL QUICKLY RAMP UP EARLY THIS
MORNING. PEAK WINDS ARE EXPECTED FROM MID/LATE MORNING THROUGH THE
AFTERNOON BEFORE SLOWLY EASING. 50 KT GUSTS LOOK LIKELY ACROSS
MUCH OF THE LAKE...ESPECIALLY THE SOUTHERN TWO-THIRDS...FROM LATE
MORNING THROUGH THE AFTERNOON. WITH ROUGHLY 6 HOURS OF GALES
EXPECTED PRIOR TO THE STORM FORCE WINDS...HAVE OPTED TO KEEP A
GALE WARNING IN EFFECT OUT THE GATE UNTIL A STORM WARNING TAKES
OVER AT 15Z FOR THE OPEN WATERS. HAVE THEN KEPT THE EXISTING GALE
WARNING FROM MID EVENING INTO THE OVERNIGHT. WILL KEEP NEARSHORE
AREAS IN A GALE...WITH STORM FORCE WINDS MORE LIKELY TO THE
EAST...BUT WILL MENTION POSSIBLE STORM FORCE GUSTS FOR THE INDIANA
WATERS. BETWEEN THE WINDS AND WAVES HEAVY FREEZING SPRAY WILL
OCCUR AND HAVE MAINTAINED THE HEAVY FREEZING SPRAY WARNING.
THE HIGH MOVES ACROSS THE GREAT LAKES SUNDAY THROUGH MONDAY WHICH
WILL LEAD TO WINDS WHICH WILL TURN EASTERLY SUNDAY AND SUNDAY NIGHT
BEFORE SOUTHWEST WINDS TAKE OVER AHEAD OF THE NEXT SERIES OF LOW
PRESSURE SYSTEMS. THIS WILL MEAN ANOTHER PERIOD OF NORTHERLY WINDS
AS WELL AS VERY COLD TEMPERATURES BY WEDNESDAY. HIGH PRESSURE IS
THEN EXPECTED TO RETURN LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...8 PM SATURDAY TO 9 AM SUNDAY.
IN...WIND ADVISORY...INZ001...9 AM SATURDAY TO 6 PM SATURDAY.
WIND CHILL ADVISORY...INZ001-INZ010-INZ011-INZ019...8 PM
SATURDAY TO 9 AM SUNDAY.
WINTER STORM WARNING...INZ002...9 AM SATURDAY TO 9 AM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM SATURDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM SATURDAY TO 3 AM
SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SUNDAY.
STORM WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 AM SATURDAY TO 9 PM
SATURDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 3
AM SUNDAY.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
331 AM CST Sat Feb 14 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST SAT FEB 14 2015
The Arctic cold front has reached southeastern Iowa and it should
reach near the Illinois river around sunrise, then progress across
the remainder of our counties this morning. The 00z models continue
to show a band of snow showers along and behind the front, with the
higher accumulations concentrating on the southwestern half of our
forecast area this morning. The upstream radar and satellite images
seem to be correlating well with the RAP area of 700-850mb
frontogenetic forcing. The forecast soundings still show limited
deep layer moisture, with disjointed saturated layers during the
morning. Dry air will likely limit the snowfall potential of the
system, but narrow bands of enhanced lift could linger in localized
areas as the mid-level forcing advances across C IL. Isolated bands
of up to 1 inch can not be ruled out in those cases, but most areas
should stay below a half inch, with some areas just seeing trace
amounts. Pinpointing exact locations of the bands is difficult even
this close to the event, and ongoing evaluation of correlating RAP
F-gen with radar and satellite will be needed through the morning to
keep any localized bands of heavier snow covered in the gridded
forecast.
Have advanced a band of likely PoPs this morning across our
southwest areas, but also included an hour or two of likely PoPs as
far north as Lincoln to Paris. Chance PoPs were included for at
least a couple hours in all of our northern counties at some point
this morning when the F-gen and moisture best coincide.
Temps will be steady or falling through the day. High temps for this
calendar day most likely will occur early this morning ahead of the
cold front. Strong pressure rises this afternoon will cause blustery
northwest winds to develop, with sustained speeds of 20-30 mph and a
few gusts around 40 mph. Wind chills by late afternoon will dip
below zero across all of our area, with -10 to -15F north of Peoria
already by 00z/6pm.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 330 AM CST SAT FEB 14 2015
Vigorous short wave to track into the mid Atlantic states this
evening and deepen a very strong surface low off the New England
coast tonight. This to bring yet another blizzard to coastal New
England including Boston tonight into Sunday. But for IL the main
story will be the bitter cold temperatures and wind chills. Will
issue a wind chill advisory tonight starting at 6 pm and go until 9
am Sunday for areas from Canton to Lincoln to Terre Haute northeast
where wind chills get down to 15-20 below zero. Lows overnight range
from zero to 5 below from Lincoln and Champaing north to 0 to 5
above south from I-72 south.
Strong 1046 mb arctic high pressure over nw Manitoba to weaken to
1035 mb as it drifts into the Great Lakes region Sunday afternoon.
Meanwhile a weak northern stream short wave will dive se from the
Pacific Northwest into the MO valley Sunday evening and bring chance
of light snow and flurries to areas sw of Lincoln later Sunday
afternoon into Sunday night. Snow accumulations of a dusting to up
to a half inch sw third of CWA possible with better chances of light
snow accumulations over sw and southern IL. Cold highs Sunday in the
teens. Lows Sunday night around 5F from I-74 ne to around 10F sw
CWA.
Dry conditions prevail Monday and Monday night with surface ridge
over IL with partly to mostly cloudy skies. Highs in mid to upper
20s which is still 10-15 degrees below normal for mid February.
00Z models continue to keep a stronger southern stream wx system
south of central IL Tue with surface low over southern MS river
valley. Have just chance of flurries far sw/southern counties on
Tue. Another surge of arctic air arrives Tue night through Wed night
with wind chills reaching near or a bit colder than 15 below over
northern counties. Dry conditions prevail rest of the week as temps
modify into low to mid 30s Friday afternoon.
The Climate Prediction Center (CPC) Day 8-14 Temperature Outlook for
Feb 21-27th has IL in a greater than 80% chance of below normal
temperatures, and this covers the Great Lakes region including IN/OH.
So winter`s grip looks to continue across the region the rest of the
month as upper level trof generally prevails over eastern North America
east of the Rockies.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1110 PM CST FRI FEB 13 2015
Low VFR cigs have dominated this evening and expect that to
continue until around 09z when a frontal boundary will approach
the area with occasional MVFR cigs with scattered snow showers.
At this point, it appears the better threat for a more organized
band of light snow will be over west central thru southeast IL
in the 11z-16z time frame where cigs and vsbys may drop briefly
to IFR. May see several narrow but intense bands of snow showers
develop towards dawn and track quickly from northwest to southeast.
Just where these narrow bands will setup and which TAF site they
will affect is still not that clear cut at this time. Will add
a tempo group for SPI and DEC for now and see how the band to our
northwest eventually sets up to see if we need to add lower cigs
and vsbys further north late tonight as well. Not looking at much
in the way of any accumulations with around a half inch possible in
a few locations tomorrow morning.
Any snow showers and lower vsbys/cigs will quickly move from
northwest to southeast during the morning and be out of the TAF
area by 18z with some scattered stratocumulus developing in the
strong cold advection pattern Saturday afternoon. Southwest winds
tonight of 10 to 15 kts will shift into the northwest by 11z
in PIA and by 14z in CMI. Look for a rapid increase in wind
speeds tomorrow morning with prevailing speeds of 15 to 25 kts
with gusts as high as 35 kts at times tomorrow morning into the
mid afternoon hours of Saturday before we see the winds gradually
diminish towards sunset Saturday evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 6 PM this evening to 9 AM CST Sunday
FOR ILZ027>031-036>038-041>046-055-057.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1200 AM CST SAT FEB 14 2015
.SHORT TERM...
328 PM CST
THROUGH SUNDAY...
HEADLINES: HAVE ISSUED A WINTER STORM WARNING FOR PORTER COUNTY
AND A WIND ADVISORY FOR LAKE COUNTY INDIANA...IN EFFECT STARTING
MID SATURDAY MORNING.
MAIN CONCERNS IN THE SHORT TERM:
*SCATTERED SNOW SHOWERS WITH ARCTIC FRONT LATE TONIGHT INTO
EARLY/MID SATURDAY MORNING.
ARCTIC FRONT TRAILING FROM LOW PRESSURE CURRENTLY OVER LAKE
SUPERIOR WILL SWEEP ACROSS THE AREA LATE TONIGHT. CORE OF -26 TO
-28C AIRMASS AT 850 MB WILL RUSH INTO THE AREA...RESULTING IN
QUICKLY STEEPENING LOW LEVEL LAPSE RATES. THIS AND NOSE OF 130+KT
UPPER JET ALONG WITH STRONG PVA FROM SHORTWAVE NOTED ON W/V
IMAGERY THIS AFTERNOON OVER WESTERN ONTARIO DIVING SOUTHWARD WILL
ENHANCE LIFT...RESULTING IN SCATTERED SNOW SHOWERS BREAKING OUT.
NOT ALL AREAS WILL SEE ANYTHING MORE THAN A DUSTING...BUT SOME
LOCATIONS ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80 COULD SEE
ROUGHLY BETWEEN A HALF INCH AND INCH OF ACCUMULATION.
CONFIDENCE IN MEDIUM-HIGH IN SNOW SHOWERS DEVELOPING AREA
WIDE...BUT HAVE MAINTAINED MID-HIGH CHANCE POPS AS EXPECTATION IS
FOR COVERAGE OF MEASURABLE SNOW TO BE SCATTERED IN NATURE.
*PLUMMETING TEMPERATURES AND VERY STRONG WINDS RESULTING IN
BITTERLY COLD WIND CHILLS LATE VALENTINES DAY INTO SATURDAY NIGHT
AND EARLY SUNDAY.
AFOREMENTIONED HIGHLY ANOMALOUS THERMAL TROUGH WILL SURGE INTO
AREA ON SATURDAY MORNING BEHIND ARCTIC FRONT. THUS HIGHS FOR THE
DAY WILL OCCUR EARLY...FOLLOWED BY QUICKLY FALLING TEMPERATURES
INTO THE SINGLE DIGITS AREA WIDE BY MID-LATE AFTERNOON. MAKING
MATTERS WORSE WILL BE RAPID NEARLY 6MB PER 3 HOUR PRESSURE RISES
LATE MORNING INTO THE EARLY AFTERNOON AS NEARLY 1050 MB ARCTIC
HIGH SPREADS SOUTH AND CLIPPER LOW DEEPENS TO SUB 1000 MB OVER
EASTERN LAKES. THIS WILL RESULT IN NORTH-NORTHWEST GUSTS TAPPING
MID TO EVEN HIGH 30S KT SPEEDS ALOFT...TRANSLATING INTO 35 TO 45
MPH WIND GUSTS AT THE SURFACE. ON THE INDIANA LAKEFRONT...WINDS
FROM FRICTIONLESS LAKE ARE LIKELY TO GUST TO 45 TO 50 MPH FROM THE
LATE MORNING THROUGH MID AFTERNOON. THUS HAVE ISSUED A WIND
ADVISORY FOR LAKE COUNTY FROM 15Z TO 00Z ON SATURDAY. THERE COULD
BE MINOR BLOWING SNOW/VSBY REDUCTION ISSUES FOR PORTIONS OF LAKE
COUNTY THAT OBSERVE FALLING SNOW THROUGH THE DAY. WILL TIE IN WIND
CONCERNS IN PORTER COUNTY INTO WINTER STORM WARNING.
WINDS WILL ONLY SLOWLY DIMINISH VALENTINES DAY EVENING AND
NIGHT...SO WIND CHILL VALUES WILL FALL TO 10 TO 20 BELOW BY EARLY
EVENING...AND THEN 15 TO 30 BELOW BY LATE SATURDAY NIGHT/EARLY
SUNDAY. WILL LIKELY NEED A WIND CHILL ADVISORY FOR MUCH OF
NORTHERN IL ALONG/NORTH OF I-80...BUT WOULD LIKE TO LET NEXT SHIFT
ASSESS POTENTIAL FOR WINDS TO DIMINISH A BIT SOONER AND RESULT IN
SLIGHTLY LESS COLD WIND CHILLS BY EARLY SUNDAY BEFORE DECIDING ON
WHAT COUNTIES TO INCLUDE IN THE ADVISORY. EXPECTING LOW
TEMPERATURES IN THE SINGLE DIGITS TO AROUND 10 BELOW ZERO AWAY
FROM LAKE EFFECT CLOUDS AND CHICAGO LAKEFRONT.
WILL ISSUE AN SPS FOR WIND/BITTER COLD/SNOW SHOWERS FOR COUNTIES
NOT YET IN HEADLINES.
*PERIODS OF MODERATE TO OCCASIONALLY HEAVY LAKE EFFECT SNOW IN
PORTER COUNTY ON SATURDAY...ALONG WITH BLOWING AND DRIFTING SNOW
AND SIGNIFICANTLY REDUCED VISIBILITY. THE LAKE EFFECT SNOW WILL
SHIFT WESTWARD LATE SATURDAY NIGHT INTO SUNDAY MORNING...BRINGING
MINOR ACCUMULATIONS TO AREAS NEAR LAKE IN NORTHEAST ILLINOIS
BEFORE ACTIVITY DIMINISHES SUNDAY AFTERNOON.
NOT MUCH HAS CHANGED REGARDING THE LAKE EFFECT SETUP SATURDAY INTO
SATURDAY NIGHT. FORECAST SOUNDINGS CONTINUE TO SHOW EXTREME LAKE
INDUCED INSTABILITY AND EQUILIBRIUM LEVELS NEAR OR OVER 10KFT...THOUGH
INVERSION HEIGHTS OF 5 TO 7KFT AS BEST CONVERGENCE MOVES INTO
PORTER COUNTY MAY PRECLUDE EXCESSIVE ACCUMULATIONS. AS BOUNDARY
LAYER FLOW SHIFTS FROM NNW TO NORTHERLY SATURDAY NIGHT...STRONG
CONVERGENCE AND HIGH INSTABILITY THROUGH DGZ COULD RESULT IN
MODERATE TO HEAVY RATES...AND LOCALIZED TOTAL ACCUMULATIONS OF
OVER 6 INCHES IN NORTHEASTERN PORTER COUNTY BY SUNDAY MORNING.
MESOLOW DEVELOPMENT AND BOUNDARY FLOW THEN BECOMING NORTHEAST THEN
EAST ON SUNDAY WILL TAKE LAKE BAND THROUGH LAKE COUNTY IN AND INTO
NORTHEAST IL BEFORE DIMINISHING. AT LEAST MINOR ACCUMULATIONS ARE
LIKELY FOR MUCH OF LAKE IN...COOK SHORE AND EVEN LAKE IL...BUT
CONFIDENCE IS LOW IN WHETHER A HEADLINE WILL BE NEEDED FOR ANY OF
THOSE COUNTIES.
DESPITE CONVERGENT AXIS REMAINING TO EAST OF PORTER ON SATURDAY
MORNING AND AFTERNOON...EXTREMELY COLD AIR MASS AND NNW FLOW WILL
LIKELY RESULT IN STEADY LIGHTER TO OCCASIONALLY MODERATE SNOW
SHOWERS INTO PORTER AND POSSIBLY EVEN EASTERN LAKE COUNTY INDIANA.
COMBINATION OF: STRONG WINDS...NEW SNOW FROM THURSDAY AND FALLING
SNOW THROUGH THE DAY ON SATURDAY BLOWING AND DRIFTING AND REDUCING
VISIBILITY...IS WHY I OPTED TO START THE WSW FOR PORTER COUNTY
SATURDAY MORNING.
RC
&&
.LONG TERM...
348 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
BELOW TO MUCH BELOW NORMAL TEMPERATURES...AND GENERALLY DRY
CONDITIONS THAT HAVE BEEN TYPICAL MUCH OF JANUARY AND FEBRUARY
WITH THE EXCEPTION OF THE SUPERBOWL SNOWSTORM LOOK TO BE IN PLACE
NEXT WORK WEEK. THIS WILL BE DUE TO CONTINUED HIGH AMPLITUDE
RIDGING FROM THE NORTHEASTERN PACIFIC INTO WESTERN NORTH
AMERICA...WITH TROUGHING OVER THE EASTERN HALF OF THE CONUS
KEEPING US IN DRY NORTH-NORTHWEST FLOW ALOFT. THE NEXT SHOT OF
BITTERLY COLD ARCTIC AIR WILL ARRIVE BY WEDNESDAY BEHIND A CLIPPER
SYSTEM THAT COULD BRING SOME LIGHT SNOW LATER MONDAY INTO EARLY
TUESDAY. THE LAKE EFFECT MACHINE WILL LIKELY FIRE UP AGAIN ON LAKE
MICHIGAN...BUT FROM THIS VANTAGE POINT...BOUNDARY LAYER FLOW COULD
KEEP THE BRUNT OF THE ACTIVITY EAST OF OUR NORTHWEST INDIANA
ACTIVITIES IN THE MID TO LATE WEEK PERIOD.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS THROUGH EARLY AFTERNOON...WITH SOME BREAKS POSSIBLE
LATE TONIGHT.
* WINDS SHIFT NORTHWEST OVERNIGHT AND INCREASE IN SPEED. GUSTS TO
AROUND 35 KT FROM MID MORNING THROUGH AT LEAST MID AFTERNOON
BEFORE GRADUALLY EASING.
* SCATTERED SNOW SHOWERS AND INTERMITTENT IFR VSBY POSSIBLE FROM
AROUND DAYBREAK THROUGH MID/LATE MORNING.
MDB
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE TO THE EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE
SOUTHEAST THROUGH THE DAY WHILE STRONG HIGH PRESSURE MOVES INTO
THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY. WEST-
SOUTHWEST WINDS CURRENTLY IN PLACE WILL TURN WEST-NORTHWEST THEN
NORTHWEST THROUGH DAYBREAK AS A COLD FRONT CROSSES THE AREA. THE
PRESSURE GRADIENT WILL STRENGTHEN AS THE HIGH BUILDS IN AND
COMBINE WITH A STRONG PUSH OF COLD AIR BRINGING GUSTY WINDS
THROUGH EARLY THIS EVENING. SPEEDS OF 20-25 KT ARE EXPECTED BY MID
MORNING WITH GUSTS INTO THE 30-35 KT RANGE...WITH SOME 35-40 KT
GUSTS POSSIBLE AT TIMES...ESPECIALLY AT GYY GIVEN THEIR PROXIMITY
TO THE LAKE. WINDS WILL EASE THIS EVENING.
CIGS HAVE SLOWLY BEEN LOWERING TO MVFR AND WILL CONTINUE TO LOWER
EARLY TONIGHT. SATELLITE SHOWS A CLEARING WEDGE ACROSS SOUTHEAST
MINNESOTA AND WEST-CENTRAL WISCONSIN WHICH IS WORKING SOUTHEAST
BUT STRATUS ACROSS NORTHERN WISCONSIN IS PUSHING SOUTHWARD AND
WILL LIKELY CLOSE THE GAP. WILL KEEP CIGS IN PLACE OVERNIGHT BUT
SOME SCATTERING IS POSSIBLE TOWARD 10Z OR SO FOR A FEW HOURS.
SNOW SHOWERS ARE EXPECTED TO DEVELOP BY AROUND DAYBREAK AS THE
COLD AIR PUSHES IN. COVERAGE IS SOMEWHAT QUESTIONABLE BUT DO
EXPECT ACTIVITY. WILL CONTINUE WITH A PERIOD OF IFR VSBY IN SHSN
BUT MAY BE ABLE TO ADJUST THIS WITH LATER UPDATES TO SHOW MORE
INTERMITTENT VSBY REDUCTION. CIGS ARE EXPECTED TO SCATTER/CLEAR
LATER THIS AFTERNOON WITH LITTLE IN THE WAY OF CLOUDS THIS
EVENING/TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN MVFR CIGS. MEDIUM CONFIDENCE IN TIME OF
SCATTERING THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS AND SEEING GUSTS AROUND 35 KT.
* MEDIUM-HIGH CONFIDENCE IN SHSN DEVELOPING THIS MORNING BUT LOW-
MEDIUM CONFIDENCE IN COVERAGE AND DURATION OF VSBY REDUCTION.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...LAKE EFFECT SNOW SHOWERS LIKELY WITH POTENTIAL IFR.
NORTHEAST WINDS.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO NORTHWEST
WINDS.
RATZER
&&
.MARINE...
221 PM CST
FOR HEADLINES...THE FREEZING SPRAY AND GALE WARNING STILL LOOK VERY
ACCURATE IN TIMING. GUIDANCE DOES NOT SUPPORT SUSTAINED STORM FORCE
GUSTS SO WILL CONTINUE TO HAVE OCNL STORM FORCE GUSTS IN THE
GLF...NO STORM FORCE HEADLINE IS EXPECTED AT THIS TIME.
HIGH PRESSURE HAS SHIFTED SE AND A WEAK LOW IS OVER SOUTH CENTRAL
ONTARIO. WINDS HAVE GRADUALLY INCREASED TO 30 KT OVER THE LAKE AND
EXPECTING THEM TO INCREASE FURTHER AS THE LOW SHIFTS OVER THE
EASTERN LAKES. THE PRESSURE GRADIENT WILL INCREASE OVERHEAD LEADING
TO GALES ACROSS THE LAKE BY EARLY SATURDAY MORNING. COULD SEE OCNL
STORM FORCE GUSTS TO 50 KT OVER THE LAKE LATE SATURDAY MORNING AND
EARLY IN THE AFTERNOON...BUT SUSTAINED STORM FORCE WINDS ARE NOT
EXPECTED AT THIS TIME. NORTH WINDS DIMINISH SATURDAY EVENING AS THE
GRADIENT WEAKENS AND THE HIGH SPREADS OVERHEAD. WINDS BECOME
NORTHEAST TO EAST SUNDAY EVENING AND CONTINUE TO VEER TO SOUTH OR
SOUTHEAST BY MONDAY MORNING. A COLD FRONT SWINGS OVER THE LAKE LATE
MONDAY NIGHT INTO EARLY TUESDAY MORNING WITH WINDS BECOMING WEST AND
THEN NORTHWEST BEHIND THE FRONT. NORTHWEST WINDS INCREASE TO 30 KT
TUESDAY NIGHT AND THEN WEAKEN AND BACK TO WEST AS A HIGH PRESSURE
SYSTEM PASSES SOUTHWEST OF LAKE THURSDAY. THE PATTERN LOOKS BUSY
GOING INTO LATE NEXT WEEK WITH ANOTHER LOW PRESSURE SYSTEM IMPACTING
THE LAKE NEXT WEEKEND.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...WINTER STORM WARNING...INZ002...9 AM SATURDAY TO 9 AM SUNDAY.
WIND ADVISORY...INZ001...9 AM SATURDAY TO 6 PM SATURDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-
LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878...3 AM SATURDAY TO 3 AM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 AM SATURDAY
TO 3 AM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1119 PM CST Fri Feb 13 2015
.UPDATE...
ISSUED AT 825 PM CST FRI FEB 13 2015
Latest surface analysis indicating the next Arctic cold front was
located over central Wisconsin southwest through north central
Iowa and is expected to sweep through our area between 6 and 9 AM
Saturday morning accompanied by scattered snow showers and a strong
northwest wind, gusting as high as 40 mph at times. Already starting
to see strong 3 hourly pressure rises across North Dakota indicating
the front should accelerate southeastward tonight with the latest
short term models continuing to suggest the boundary will be south
of most of our area by early afternoon.
Weak shortwave noted on the water vapor loop over western North
Dakota has a small area of light snow associated with it as it
tracks southeast. HRRR and Rapid Refresh models indicate the better
threat for snow showers with this weak wave would be over west
central thru southeast IL tomorrow morning. HRRR indicating around
0.05 inches of QPF associated with this band of light snow which
would be just under an inch of snow. However, this situation is
very similar to a couple of days ago in which we saw some very
narrow but intense bands of snow showers just behind the Artic
boundary, which lasted less than an hour in most locations with
most areas seeing less than a half inch. The main concern with
this particular front will be with the strong pressure rises
immediately behind the boundary tomorrow morning suggesting about
a 2 to 4 hour period of strong winds with gusts around 40 mph out
of the northwest tomorrow morning into the mid afternoon hours.
Whatever we see with respect to light snow should be well south of
our area by mid afternoon as the Arctic air mass settles across
the Midwest for the remainder of the weekend.
Have made some minor tweaks to the early evening temperatures
and POPs, especially across west central IL just before dawn
Saturday. The rest of the forecast is right on track this evening.
Updated ZFP out by 900 PM.
&&
.SHORT TERM...(Tonight)
ISSUED AT 257 PM CST FRI FEB 13 2015
Arctic cold front currently across the Upper Midwest will drop
southward into north-central Illinois tonight, reaching the I-74
corridor by dawn Saturday. Models continue to depict a band of
snow-showers accompanying the front as it quickly passes late
tonight into Saturday morning. 18z NAM time-height cross-sections
show strong lift within the 850-700mb layer along/ahead of the
boundary, but do not indicate full saturation within the profile.
Despite lack of deep moisture, think low-level convergence/lift will
be sufficient to trigger scattered snow-showers across the northern
KILX CWA late tonight. Have therefore included chance PoPs
along/north of I-74 after 3am. Further south, dry conditions will
prevail through the night. Winds will initially be W/SW this
evening, but will veer to the N/NW and increase markedly once the
front passes. Will likely see wind gusts in the 30-35mph range
across the far north by dawn. Overnight low temperatures will
mainly be in the lower to middle 20s, but will drop into the teens
north of a Canton to Bloomington-Normal line.
&&
.LONG TERM...(Saturday through Friday)
ISSUED AT 257 PM CST FRI FEB 13 2015
A vigorous clipper system, currently diving across the Canadian
Prairies, will impact central and southeast Illinois on Saturday.
While the center of the surface low and better moisture will pass
well north/east of the forecast area, the gusty winds associated
with the system and cold temperatures in its wake will be featured
prominently across the area. The trailing cold front will dive
across the area early Saturday, with temperatures falling through
most of the day. There will be minimal moisture for the front to
work with as it dives through the area, but it should still be able
to squeeze out a few snow showers or flurries as forecast soundings
suggest ice crystals will be present. Still looking like a a Wind
Chill Advisory will be needed later Saturday night into Sunday
morning across the far northern portion of the forecast area,
especially along/north of the I-74 corridor. Even in areas where
advisory criteria will not be specifically met, it will be bitterly
cold Saturday night into Sunday.
Another wave will dive toward the area by late Sunday into early
Monday, but this one is progged to come ashore along the Pacific
Northwest. As such, the best forcing/snow chances with this system
should stay just to our south. That being said, at least the
southern fringe of the forecast area is in line to be impacted by
some jet/frontogenetical forcing associated with this wave. Still
expect most of the forecast area to be missed by this wave, but snow
accumulations as high an inch or two could be seen south of I-70.
The additional energy that follows the lead Pacific wave is now
expected to stay well south of the forecast area Monday/Tuesday as
the North American trof broadens to encompass much more of the
continent. No additional disturbances of consequence are currently
expected for the remainder of the forecast period. Temperatures will
remain below to well below normal.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1110 PM CST FRI FEB 13 2015
Low VFR cigs have dominated this evening and expect that to
continue until around 09z when a frontal boundary will approach
the area with occasional MVFR cigs with scattered snow showers.
At this point, it appears the better threat for a more organized
band of light snow will be over west central thru southeast IL
in the 11z-16z time frame where cigs and vsbys may drop briefly
to IFR. May see several narrow but intense bands of snow showers
develop towards dawn and track quickly from northwest to southeast.
Just where these narrow bands will setup and which TAF site they
will affect is still not that clear cut at this time. Will add
a tempo group for SPI and DEC for now and see how the band to our
northwest eventually sets up to see if we need to add lower cigs
and vsbys further north late tonight as well. Not looking at much
in the way of any accumulations with around a half inch possible in
a few locations tomorrow morning.
Any snow showers and lower vsbys/cigs will quickly move from
northwest to southeast during the morning and be out of the TAF
area by 18z with some scattered stratocumulus developing in the
strong cold advection pattern Saturday afternoon. Southwest winds
tonight of 10 to 15 kts will shift into the northwest by 11z
in PIA and by 14z in CMI. Look for a rapid increase in wind
speeds tomorrow morning with prevailing speeds of 15 to 25 kts
with gusts as high as 35 kts at times tomorrow morning into the
mid afternoon hours of Saturday before we see the winds gradually
diminish towards sunset Saturday evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Smith
SHORT TERM...Barnes
LONG TERM...Bak
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
222 AM CST SAT FEB 14 2015
...UPDATE TO LONG TERM...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 147 AM CST SAT FEB 14 2015
MODELS THIS MORNING WERE IN GOOD AGREEMENT WITH A COLD FRONT
CROSSING SOUTHWEST KANSAS BETWEEN 15Z AND 12Z AS AN UPPER LEVEL
TROUGH CROSSES THE GREAT LAKES REGION. NAM, GFS, RAP, AND HRRR
WERE ALSO IN GOOD AGREEMENT WITH THE COLDER AIR IN THE LOWER
LEVELS INVADING WESTERN KANSAS BEHIND THIS COLD FRONT DURING THE
LATE MORNING AND AFTERNOON. SOME LOW CLOUDS WILL ALSO BE SPREADING
SOUTHWEST INTO PORTIONS OF WESTERN KANSAS DURING THE AFTERNOON AND
EVENING HOURS BASED THE 900MB TO 875MB LEVEL RH FIELD AND 00Z NAM
BUFR SOUNDINGS. GIVEN THIS INCREASING CLOUDS, ESPECIALLY IN THE
NORTH, AND COOLING TEMPERATURES FORECAST IN THE LOWER LEVELS BY
ALL THE MODELS WILL STAY CLOSE TO THE PREVIOUS FORECAST WITH AN
EARLY HIGH IN THE UPPER 30S ACROSS NORTH CENTRAL KANSAS. 18Z AND
21Z SATURDAY NAM BUFR SOUNDINGS SUPPORT THE POTENTIAL FOR HIGHS
APPROACHING 70 DEGREES IN EXTREME SOUTHWEST KANSAS. HIGH
TEMPERATURES TODAY BETWEEN THESE TWO EXTREMES ARE MORE UNCERTAIN
GIVEN THE TIMING ON THE FRONTAL PASSAGE AND HOW QUICKLY THE COLD
AIR ADVECTION DEVELOPS IS BEHIND THIS COLD FRONT. GUSTY WINDS OF
20 TO 25 MPH WILL ALSO BE LIKELY THIS AFTERNOON BEHIND THIS COLD
FRONT BASED ON MEAN MIXED LAYER WINDS FROM THE NAM AND GFS BETWEEN
18Z SATURDAY AND 00Z SUNDAY.
TONIGHT THE 900 TO 875MB MOISTURE WILL SHIFT EAST TO THE COLORADO
BORDER AND AN EASTERLY UPSLOPE FLOW WILL IMPROVE ACROSS WESTERN
KANSAS. AT THIS TIME BASED ON VARIOUS MODEL SOUNDINGS IN WEST
CENTRAL KANSAS THE DEPTH OF THIS MOIST LAYER WILL NOT BE DEEP
ENOUGH TO SUPPORT ANY LIGHT PRECIPITATION DURING THE OVERNIGHT
HOURS. AFTER MIDNIGHT MID AND HIGH LEVEL MOISTURE WILL BEGIN TO
INCREASE ACROSS ALL OF WESTERN KANSAS AS AN UPPER LEVEL TROUGH
APPROACHES THE CENTRAL ROCKIES FROM THE NORTHWEST. THIS INCREASING
CLOUD MAY LIMIT HOW COLD TEMPERATURES WILL BY 12Z SUNDAY. AS A
RESULT WILL TREND OVERNIGHT LOWS TOWARD THE WARMER MET GUIDANCE
FOR OVERNIGHT LOWS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 222 AM CST SAT FEB 14 2015
SUNDAY LOOKS TO BE A RATHER COLD DAY. THERE ARE SOME DIFFERENCES BETWEEN
THE ECMWF AND AND THE GFS. JUST FROM A PATTERN RECOGNITION STANDPOINT,
SUNDAY LOOKS TO BE AN UPSLOPE/STRATUS DAY. THE ECE GUIDANCE IS CONSIDERABLY
COLDER THAN THE MEX (30 VERSUS 41 FOR DDC FOR EXAMPLE). HAVE UNDERCUT
THE INHERITED MAXIMUM TEMPERATURE GRID BY SEVERAL DEGREES TO SIDE MORE
WITH THE ECMWF. TO ADD TO THE UNCERTAINTY, ENSEMBLE SPREAD ISN`T THAT
HELPFUL EITHER WITH A HIGH OF 41 TO A LOW OF 29. STILL, FORECAST SOUNDINGS
SHOW LOW LEVEL SATURATION AND THINK THAT THE GFS IS TRYING TO CLEAR
SKIES OUT QUICKER THAN WHAT NORMALLY OCCURS. THERE COULD BE SOME FLURRIES
SUNDAY EVENING ACROSS THE REGION AS AN 110 KT 250-HPA RIGHT ENTRANCE
REGION JET STREAK MOVES ACROSS. OTHER THAN THIS, DYNAMICS IS NOT PARTICULARLY
THAT IMPRESSIVE WITH A POSITIVELY TILTED SYNOPTIC SYSTEM. A BETTER CHANCE
OF SNOW FOR FAR SOUTHWEST KANSAS IS POSSIBLE MONDAY WITH BETTER UPSLOPE
FLOW AND A SUBTLE VORTMAX MOVING THROUGH AT THE BASE OF THE TROUGH.
WILL CONTINUE WITH CHANCE POPS FOR FAR SOUTHWEST KANSAS. THERE COULD
BE LIGHT SNOW ACCUMULATION BY THE TIME IT`S ALL SAID AND DONE WITH ACROSS
FAR SW KANSAS. HAVE JUST OVER AN INCH ACROSS MORTON COUNTY, BUT THIS
MIGHT BE PUSHING IT ON THE HIGH SIDE. THE GFS IS SLIGHTLY MORE EAST
WITH THE FRONTOGENETIC ZONE AND RESULTANT QPF THAN COMPARED TO THE ECMWF,
SO THERE IS STILL SOME UNCERTAINTY. MONDAYS HIGHS SHOULD TO BE A LITTLE
WARMER WITH DOWNSLOPE NORTHWESTERLY WINDS. BEYOND THAT, TEMPERATURES
WILL MODERATE SOMEWHAT, BUT STILL BE A LITTLE BELOW NORMAL. COULD SEE
RATHER PLEASANT TEMPERATURES BY THE END OF THE UPCOMING BUSINESS WEEK,
BUT CONFIDENCE IS PRETTY LOW. DOESN`T LOOK LIKE ANY SIGNIFICANT PRECIPITATION
ANYTIME SOON IN THE FORM OF RAIN AND/OR SNOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI FEB 13 2015
NAM, RAP, AND HRRR WERE ALL IN DECENT AGREEMENT THIS MORNING WILL
MOVING A COLD FRONT ACROSS SOUTHWEST KANSAS BETWEEN 15Z AND 21Z
SATURDAY. AS THIS FRONT PASSES A SOUTHWEST/WESTERLY WIND AT 10
KNOTS OR LESS WILL SHIFT TO THE NORTHEAST AND THEN INCREASE TO
AROUND 20 KNOTS. AT THIS TIME FRONTAL PASSAGE IS EXPECTED AT HAYS
AROUND 15Z AND THEN AT DODGE CITY AND GARDEN CITY AROUND 18Z.
GUSTY WINDS BEHIND THIS FRONT WILL GRADUALLY VEER MORE EASTERLY BY
00Z SUNDAY AND AFTER 03Z SUNDAY DECREASE INTO THE 10 TO 15 KNOT
RANGE. NAM BUFR SOUNDINGS DOES INDICATED SOME INCREASING MOISTURE
IN THE 2000 TO 3000FT AGL LEVEL BEHIND THIS FRONT AFTER 18Z IN
MAINLY THE HAYS AREA SO A PERIOD OF MVFR CEILINGS IS ANTICIPATED
LATER TODAY IN NORTH CENTRAL KANSAS. ELSEWHERE VFR CONDITIONS ARE
EXPECTED THROUGH THE EARLY EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 58 15 29 20 / 0 0 10 10
GCK 58 16 32 21 / 0 0 10 20
EHA 69 21 41 25 / 0 0 10 20
LBL 66 18 34 22 / 0 10 10 20
HYS 39 12 28 19 / 0 0 10 10
P28 59 16 28 17 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
148 AM CST SAT FEB 14 2015
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 147 AM CST SAT FEB 14 2015
MODELS THIS MORNING WERE IN GOOD AGREEMENT WITH A COLD FRONT
CROSSING SOUTHWEST KANSAS BETWEEN 15Z AND 12Z AS AN UPPER LEVEL
TROUGH CROSSES THE GREAT LAKES REGION. NAM, GFS, RAP, AND HRRR
WERE ALSO IN GOOD AGREEMENT WITH THE COLDER AIR IN THE LOWER
LEVELS INVADING WESTERN KANSAS BEHIND THIS COLD FRONT DURING THE
LATE MORNING AND AFTERNOON. SOME LOW CLOUDS WILL ALSO BE SPREADING
SOUTHWEST INTO PORTIONS OF WESTERN KANSAS DURING THE AFTERNOON AND
EVENING HOURS BASED THE 900MB TO 875MB LEVEL RH FIELD AND 00Z NAM
BUFR SOUNDINGS. GIVEN THIS INCREASING CLOUDS, ESPECIALLY IN THE
NORTH, AND COOLING TEMPERATURES FORECAST IN THE LOWER LEVELS BY
ALL THE MODELS WILL STAY CLOSE TO THE PREVIOUS FORECAST WITH AN
EARLY HIGH IN THE UPPER 30S ACROSS NORTH CENTRAL KANSAS. 18Z AND
21Z SATURDAY NAM BUFR SOUNDINGS SUPPORT THE POTENTIAL FOR HIGHS
APPROACHING 70 DEGREES IN EXTREME SOUTHWEST KANSAS. HIGH
TEMPERATURES TODAY BETWEEN THESE TWO EXTREMES ARE MORE UNCERTAIN
GIVEN THE TIMING ON THE FRONTAL PASSAGE AND HOW QUICKLY THE COLD
AIR ADVECTION DEVELOPS IS BEHIND THIS COLD FRONT. GUSTY WINDS OF
20 TO 25 MPH WILL ALSO BE LIKELY THIS AFTERNOON BEHIND THIS COLD
FRONT BASED ON MEAN MIXED LAYER WINDS FROM THE NAM AND GFS BETWEEN
18Z SATURDAY AND 00Z SUNDAY.
TONIGHT THE 900 TO 875MB MOISTURE WILL SHIFT EAST TO THE COLORADO
BORDER AND AN EASTERLY UPSLOPE FLOW WILL IMPROVE ACROSS WESTERN
KANSAS. AT THIS TIME BASED ON VARIOUS MODEL SOUNDINGS IN WEST
CENTRAL KANSAS THE DEPTH OF THIS MOIST LAYER WILL NOT BE DEEP
ENOUGH TO SUPPORT ANY LIGHT PRECIPITATION DURING THE OVERNIGHT
HOURS. AFTER MIDNIGHT MID AND HIGH LEVEL MOISTURE WILL BEGIN TO
INCREASE ACROSS ALL OF WESTERN KANSAS AS AN UPPER LEVEL TROUGH
APPROACHES THE CENTRAL ROCKIES FROM THE NORTHWEST. THIS INCREASING
CLOUD MAY LIMIT HOW COLD TEMPERATURES WILL BY 12Z SUNDAY. AS A
RESULT WILL TREND OVERNIGHT LOWS TOWARD THE WARMER MET GUIDANCE
FOR OVERNIGHT LOWS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 223 PM CST FRI FEB 13 2015
RETROGRESSION OF THE UPPER LEVEL LONG WAVE PATTERN IS IN PROGRESS,
AND CONSIDERABLY COOLER WEATHER WILL RETURN TO THE CENTRAL PLAINS
AND PERSIST FOR THE REST OF FEBRUARY. WHEREAS THE FIRST PART OF THE
MONTH WAS CHARACTERIZED BY A RIDGE CENTERED 110-120W AND A PLUME OF
DOWNSLOPE-WARMED AIR IN THE PLAINS, THE REST OF THE MONTH IS LIKELY
TO BE CHARACTERIZED BY A LONG WAVE RIDGE CENTERED 120-130W AND ONLY
BRIEF PERIODS OF WARMING BETWEEN SURGES OF COLD AIR.
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT ON EVOLUTION OF THE LARGE
SCALE FLOW, ALTHOUGH DIFFERENCES IN SYNOPTIC SCALE DETAILS BECOME
MORE EVIDENT BY LATE NEXT WEEK. THE ECMWF HAS TRENDED TOWARD THE
DRIER GFS SOLUTION FOR THE MINOR PRECIPITATION EVENT MONDAY AND
SEEMS REASONABLE. THE ECMWF IS SLOWER TO ERODE THE MODIFIED ARCTIC
AIR THAN THE GFS ON WEDNESDAY, AND THE GFS APPEARS TO GENERATE
EXCESSIVE LEE TROUGHING WITH STRONGLY MERIDIONAL FLOW. THE
DETERMINISTIC ECMWF SEEMS MORE REASONABLE BY THE MIDDLE OF NEXT
WEEK. THE ECMWF HAS MORE AMPLITUDE WITH THE UPPER LEVEL TROUGH THAT
REACHES THE WEST COAST THURSDAY THAN THE GFS AND BRINGS A MUCH
STRONGER TROUGH INTO THE SOUTHERN PLAINS FRIDAY NIGHT THAN DOES THE
GFS. MOST OF THE GFS ENSEMBLES MAINTAIN A SPLIT FLOW WITH A PORTION
OF THE TROUGH HANGING BACK IN THE SOUTHWESTERN UNITED STATES, AND
THE WEAKER GFS SOLUTION IS PREFERRED FOR NEXT WEEKEND.
THE COLD AIR MASS THAT WILL INVADE KANSAS SATURDAY AND SATURDAY
NIGHT WILL REMAIN ENTRENCHED IN THE CENTRAL PART OF THE COUNTRY
THROUGH WEDNESDAY. A MINOR UPPER LEVEL TROUGH NEAR 45N/145W THIS
AFTERNOON WILL PROGRESS THROUGH THE EASTERN PACIFIC RIDGE AND REACH
KANSAS ON SUNDAY. LOW LEVEL MOISTURE IN SOUTHWEST TEXAS WILL FLOW
NORTH OVER THE ARCTIC AIR AND SHOULD RESULT IN FORMATION OF
WIDESPREAD STRATUS SATURDAY NIGHT AND SUNDAY AS WINDS BECOME SOUTH
ABOVE THE ARCTIC AIR. MODEL SOUNDINGS SUGGEST THAT THE MOISTURE
LAYER WILL BE SHALLOW AND THAT HIGH DEWPOINT DEPRESSIONS WILL EXIST
BELOW THE MOIST LAYER. AS SUCH, THE POTENTIAL FOR FREEZING DRIZZLE
WITH THE LOW LEVEL ISENTROPIC LIFTING SEEMS MINIMAL IN WESTERN
KANSAS. THE STRATUS WILL BE SLOW TO DISSIPATE ON SUNDAY BUT LIKELY
WILL ERODE FROM WEST TO EAST AS LOW LEVEL WINDS BECOME MORE NORTH
FOLLOWING PASSAGE OF THE UPPER LEVEL TROUGH. THERE IS A CHANCE THAT
THERE COULD BE A FEW SNOW FLURRIES SUNDAY AFTERNOON WITH THE TROUGH,
BUT MODEL SOUNDINGS HAVE QUITE A BIT OF DRY AIR IN THE MID LEVELS TO
EVAPORATE MOST OF ANY PRECIPITATION THAT DEVELOPS.
TEMPERATURES SATURDAY NIGHT ARE SOMEWHAT PROBLEMATIC GIVEN THE COLD
AIR ADVECTION AND THE CLOUD COVER. THE REALLY COLD ARCTIC AIR WILL
REMAIN WELL EAST OF KANSAS, AND TEMPERATURES PROBABLY WILL NOT BE
ALL THAT FRIGID IN SOUTHWESTERN KANSAS. VALUES WERE ADJUSTED UP
SLIGHTLY. SUNDAY WILL BE COOL WITH CONSIDERABLE CLOUD COVER,
ESPECIALLY IN CENTRAL AND SOUTH CENTRAL KANSAS. THERE SHOULD BE
ENOUGH SUN TO ALLOW HIGHS IN THE LOW TO MID 40S IN FAR SOUTHWEST
KANSAS.
THE POTENTIAL FOR MEASURABLE PRECIPITATION WITH THE UPPER LEVEL
TROUGH THAT APPROACHES THE FOUR CORNERS AREA MONDAY EVENING IS NOT
THAT GREAT IN WESTERN KANSAS. UPWARD VERTICAL MOTION APPEARS TO BE
QUITE WEAK EAST OF THE COLORADO BORDER WITH WEAK MID LEVEL
FRONTOGENESIS AND MARGINAL DIFFERENTIAL POSITIVE VORTICITY ADVECTION
WITH THE DIGGING UPPER LEVEL TROUGH. SNOWFALL TOTALS WILL BE QUITE
LIGHT, AND ANYTHING MORE THAN AN INCH PROBABLY WILL BE RESTRICTED
TO MORTON COUNTY.
A STRONG JET STREAK IN THE NORTHWEST FLOW WILL MOVE INTO WESTERN
KANSAS TUESDAY, AND DIVERGENCE IN THE EXIT REGION OF THE JET STREAK
MAY PRODUCE ENOUGH VERTICAL MOTION FOR A FEW SNOW FLURRIES TUESDAY
AFTERNOON. SOME EROSION OF THE ARCTIC AIR WILL OCCUR IN FAR WESTERN
KANSAS WEDNESDAY, BUT THE GFS APPEARS TOO QUICK TO ERODE THE COLD
AIR. THE COLD AIR WILL SLOSH BACK WEST WEDNESDAY NIGHT AS YET
ANOTHER UPPER LEVEL TROUGH DROPS INTO THE UPPER MIDWEST. THE UPPER
LEVEL FLOW WILL BECOME LESS MERIDIONAL THURSDAY AND FRIDAY AS A
TROUGH MOVES THROUGH THE LONG WAVE RIDGE INTO THE WESTERN UNITED
STATES, AND DOWNSLOPE FLOW SHOULD SCOUR OUT THE REMNANTS OF THE
ARCTIC AIR THURSDAY AFTERNOON AND NIGHT. COOLER AIR WILL RETURN NEXT
WEEKEND, BUT THE DETAILS ARE UNCERTAIN. IF THE UPPER LEVEL TROUGH
COMES OUT IN ONE PIECE LIKE THE ECMWF ADVERTISES, THERE WILL BE A
CHANCE FOR LIGHT PRECIPITATION IN WESTERN KANSAS; HOWEVER, THE
WEAKER GFS SOLUTION SEEMS MORE REASONABLE.
ADDITIONAL SURGES OF COLD AIR ARE LIKELY EVERY FEW DAYS UNTIL A MORE
ZONAL FLOW REGIME RETURNS IN EARLY MARCH. THERE IS LITTLE INDICATION
THAT SIGNIFICANT PRECIPITATION IS LIKELY IN THE NEAR FUTURE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI FEB 13 2015
NAM, RAP, AND HRRR WERE ALL IN DECENT AGREEMENT THIS MORNING WILL
MOVING A COLD FRONT ACROSS SOUTHWEST KANSAS BETWEEN 15Z AND 21Z
SATURDAY. AS THIS FRONT PASSES A SOUTHWEST/WESTERLY WIND AT 10
KNOTS OR LESS WILL SHIFT TO THE NORTHEAST AND THEN INCREASE TO
AROUND 20 KNOTS. AT THIS TIME FRONTAL PASSAGE IS EXPECTED AT HAYS
AROUND 15Z AND THEN AT DODGE CITY AND GARDEN CITY AROUND 18Z.
GUSTY WINDS BEHIND THIS FRONT WILL GRADUALLY VEER MORE EASTERLY BY
00Z SUNDAY AND AFTER 03Z SUNDAY DECREASE INTO THE 10 TO 15 KNOT
RANGE. NAM BUFR SOUNDINGS DOES INDICATED SOME INCREASING MOISTURE
IN THE 2000 TO 3000FT AGL LEVEL BEHIND THIS FRONT AFTER 18Z IN
MAINLY THE HAYS AREA SO A PERIOD OF MVFR CEILINGS IS ANTICIPATED
LATER TODAY IN NORTH CENTRAL KANSAS. ELSEWHERE VFR CONDITIONS ARE
EXPECTED THROUGH THE EARLY EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 58 15 36 19 / 0 0 0 10
GCK 58 16 40 20 / 0 0 0 10
EHA 69 21 45 24 / 0 0 0 20
LBL 66 18 41 22 / 0 10 0 10
HYS 39 12 31 18 / 0 0 10 10
P28 59 16 31 18 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...RUTHI
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1121 PM CST FRI FEB 13 2015
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1119 PM CST FRI FEB 13 2015
AT 00Z SATURDAY AN UPPER LEVEL RIDGE AXIS EXTENDED FROM THE
WESTERN UNITED STATES INTO WESTERN ALBERTA. A +120KT 250MB JET
STREAK WAS LOCATED JUST WEST OF THIS UPPER LEVEL RIDGE AXIS AND
STRETCHED FROM EAST CENTRAL ALBERTA TO NORTHWEST NORTH DAKOTA. A
500MB TROUGH WAS LOCATED NEAR THE LEFT EXIT REGION OF THIS UPPER
LEVEL JET. AN AREA OF HIGHER MID LEVEL MOISTURE WAS PRESENT ACROSS
NORTH AND SOUTH DAKOTA AT 00Z SATURDAY WHICH WAS NEAR THE NOSE OF
THE 250MB JET AND JUST EAST OF A 700MB -2C TO -6C TEMPERATURE
GRADIENT. A 850MB COLD FRONT EXTENDED FROM WISCONSIN INTO EASTERN
NORTH DAKOTAS WITH -15C TO -20C TEMPERATURES OBSERVED NORTH OF
THIS FRONT OVER MINNESOTA AND NORTHERN WISCONSIN. THE SURFACE COLD
FRONT STRETCHED FROM SOUTHERN WISCONSIN TO NORTHEAST NEBRASKA TO
SOUTHEAST MONTANA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 200 PM CST FRI FEB 13 2015
NORTHWEST FLOW ALOFT WILL CONTINUE OVER WESTERN KANSAS THROUGH THE
PERIOD. SOME RESIDUAL MID LEVEL MOISTURE, LIKELY BEING FORCED BY
SOME WEAK MID LEVEL WARM ADVECTION, WAS RESULTING IN AN AREA OF
CLOUDS OVER SOUTHWEST NEBRASKA AND NORTHWEST KANSAS THIS MORNING AND
EARLY AFTERNOON. SATELLITE TRENDS SHOW THIS AREA OF CLOUDS GRADUALLY
THINNING OUT WITH TIME SO WILL CONTINUE THE TREND FOR MOSTLY CLEAR
SKIES THROUGH THE EVENING AND OVERNIGHT HOURS. A WEAK SURFACE
PRESSURE PATTERN WILL ALSO CONTINUE TONIGHT ACROSS WESTERN KANSAS.
THE SURFACE WINDS ARE EXPECTED TO SETTLE INTO A WESTERLY DIRECTION
OVERNIGHT WHICH COULD HELP KEEP TEMPERATURES UP SOMEWHAT BUT GIVEN
THE CLEAR SKIES AND LOWER DEWPOINTS, WE SHOULD SEE TEMPERATURES
FALLING INTO THE LOWER TO MIDDLE 30S.
ON SATURDAY, A STRONG COLD FRONT WILL BACKDOOR INTO CENTRAL AND
SOUTHWEST KANSAS FROM THE NORTH/NORTHEAST, IN RESPONSE TO A CLOSED
UPPER LOW THAT WILL BE DROPPING RAPIDLY OUT OF CANADA AND THROUGH
THE GREAT LAKES REGION ON SATURDAY. THE NAM SEEMS TO BE A LITTLE
SLOWER WITH THIS FRONT COMPARED TO OTHER MODELS WHICH IS SOMEWHAT
CURIOUS AS IT SEEMS THESE FRONTS ARE USUALLY A LITTLE MORE
PROGRESSIVE THAN WHAT THE MODELS SHOW. AT ANY RATE, THERE WILL
LIKELY BE A NON DIURNAL TEMPERATURE PROFILE DURING THE DAY ACROSS
PROBABLY ALL BUT THE FAR SOUTHWEST COUNTIES AND THIS WILL BE
REFLECTED IN THE HOURLY TEMPERATURE FORECASTS. HAYS WILL BE THE
COOLEST DURING THE DAY AND MAY RISE A FEW DEGREES IN THE MORNING BUT
WILL SEE TEMPERATURES FALLING OFF THROUGH THE LATE MORNING AND
AFTERNOON. EXPECT HIGH TEMPERATURES THERE TO ONLY RISE INTO THE LOW
40S BEFORE FALLING BACK. FARTHER SOUTHWEST, HIGHS COULD REACH THE
MID AND UPPER 50S FROM GARDEN CITY AND DODGE CITY THROUGH MEDICINE
LODGE WITH UPPER 60S TO NEAR 70 DEGREES POSSIBLE AT ELKHART AND
HUGOTON. MODEL SOUNDINGS ALSO SUGGEST THAT LOW STRATUS WILL BE
DEVELOPING IN THE STRONG COLD ADVECTION ZONE BEHIND THE FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 223 PM CST FRI FEB 13 2015
RETROGRESSION OF THE UPPER LEVEL LONG WAVE PATTERN IS IN PROGRESS,
AND CONSIDERABLY COOLER WEATHER WILL RETURN TO THE CENTRAL PLAINS
AND PERSIST FOR THE REST OF FEBRUARY. WHEREAS THE FIRST PART OF THE
MONTH WAS CHARACTERIZED BY A RIDGE CENTERED 110-120W AND A PLUME OF
DOWNSLOPE-WARMED AIR IN THE PLAINS, THE REST OF THE MONTH IS LIKELY
TO BE CHARACTERIZED BY A LONG WAVE RIDGE CENTERED 120-130W AND ONLY
BRIEF PERIODS OF WARMING BETWEEN SURGES OF COLD AIR.
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT ON EVOLUTION OF THE LARGE
SCALE FLOW, ALTHOUGH DIFFERENCES IN SYNOPTIC SCALE DETAILS BECOME
MORE EVIDENT BY LATE NEXT WEEK. THE ECMWF HAS TRENDED TOWARD THE
DRIER GFS SOLUTION FOR THE MINOR PRECIPITATION EVENT MONDAY AND
SEEMS REASONABLE. THE ECMWF IS SLOWER TO ERODE THE MODIFIED ARCTIC
AIR THAN THE GFS ON WEDNESDAY, AND THE GFS APPEARS TO GENERATE
EXCESSIVE LEE TROUGHING WITH STRONGLY MERIDIONAL FLOW. THE
DETERMINISTIC ECMWF SEEMS MORE REASONABLE BY THE MIDDLE OF NEXT
WEEK. THE ECMWF HAS MORE AMPLITUDE WITH THE UPPER LEVEL TROUGH THAT
REACHES THE WEST COAST THURSDAY THAN THE GFS AND BRINGS A MUCH
STRONGER TROUGH INTO THE SOUTHERN PLAINS FRIDAY NIGHT THAN DOES THE
GFS. MOST OF THE GFS ENSEMBLES MAINTAIN A SPLIT FLOW WITH A PORTION
OF THE TROUGH HANGING BACK IN THE SOUTHWESTERN UNITED STATES, AND
THE WEAKER GFS SOLUTION IS PREFERRED FOR NEXT WEEKEND.
THE COLD AIR MASS THAT WILL INVADE KANSAS SATURDAY AND SATURDAY
NIGHT WILL REMAIN ENTRENCHED IN THE CENTRAL PART OF THE COUNTRY
THROUGH WEDNESDAY. A MINOR UPPER LEVEL TROUGH NEAR 45N/145W THIS
AFTERNOON WILL PROGRESS THROUGH THE EASTERN PACIFIC RIDGE AND REACH
KANSAS ON SUNDAY. LOW LEVEL MOISTURE IN SOUTHWEST TEXAS WILL FLOW
NORTH OVER THE ARCTIC AIR AND SHOULD RESULT IN FORMATION OF
WIDESPREAD STRATUS SATURDAY NIGHT AND SUNDAY AS WINDS BECOME SOUTH
ABOVE THE ARCTIC AIR. MODEL SOUNDINGS SUGGEST THAT THE MOISTURE
LAYER WILL BE SHALLOW AND THAT HIGH DEWPOINT DEPRESSIONS WILL EXIST
BELOW THE MOIST LAYER. AS SUCH, THE POTENTIAL FOR FREEZING DRIZZLE
WITH THE LOW LEVEL ISENTROPIC LIFTING SEEMS MINIMAL IN WESTERN
KANSAS. THE STRATUS WILL BE SLOW TO DISSIPATE ON SUNDAY BUT LIKELY
WILL ERODE FROM WEST TO EAST AS LOW LEVEL WINDS BECOME MORE NORTH
FOLLOWING PASSAGE OF THE UPPER LEVEL TROUGH. THERE IS A CHANCE THAT
THERE COULD BE A FEW SNOW FLURRIES SUNDAY AFTERNOON WITH THE TROUGH,
BUT MODEL SOUNDINGS HAVE QUITE A BIT OF DRY AIR IN THE MID LEVELS TO
EVAPORATE MOST OF ANY PRECIPITATION THAT DEVELOPS.
TEMPERATURES SATURDAY NIGHT ARE SOMEWHAT PROBLEMATIC GIVEN THE COLD
AIR ADVECTION AND THE CLOUD COVER. THE REALLY COLD ARCTIC AIR WILL
REMAIN WELL EAST OF KANSAS, AND TEMPERATURES PROBABLY WILL NOT BE
ALL THAT FRIGID IN SOUTHWESTERN KANSAS. VALUES WERE ADJUSTED UP
SLIGHTLY. SUNDAY WILL BE COOL WITH CONSIDERABLE CLOUD COVER,
ESPECIALLY IN CENTRAL AND SOUTH CENTRAL KANSAS. THERE SHOULD BE
ENOUGH SUN TO ALLOW HIGHS IN THE LOW TO MID 40S IN FAR SOUTHWEST
KANSAS.
THE POTENTIAL FOR MEASURABLE PRECIPITATION WITH THE UPPER LEVEL
TROUGH THAT APPROACHES THE FOUR CORNERS AREA MONDAY EVENING IS NOT
THAT GREAT IN WESTERN KANSAS. UPWARD VERTICAL MOTION APPEARS TO BE
QUITE WEAK EAST OF THE COLORADO BORDER WITH WEAK MID LEVEL
FRONTOGENESIS AND MARGINAL DIFFERENTIAL POSITIVE VORTICITY ADVECTION
WITH THE DIGGING UPPER LEVEL TROUGH. SNOWFALL TOTALS WILL BE QUITE
LIGHT, AND ANYTHING MORE THAN AN INCH PROBABLY WILL BE RESTRICTED
TO MORTON COUNTY.
A STRONG JET STREAK IN THE NORTHWEST FLOW WILL MOVE INTO WESTERN
KANSAS TUESDAY, AND DIVERGENCE IN THE EXIT REGION OF THE JET STREAK
MAY PRODUCE ENOUGH VERTICAL MOTION FOR A FEW SNOW FLURRIES TUESDAY
AFTERNOON. SOME EROSION OF THE ARCTIC AIR WILL OCCUR IN FAR WESTERN
KANSAS WEDNESDAY, BUT THE GFS APPEARS TOO QUICK TO ERODE THE COLD
AIR. THE COLD AIR WILL SLOSH BACK WEST WEDNESDAY NIGHT AS YET
ANOTHER UPPER LEVEL TROUGH DROPS INTO THE UPPER MIDWEST. THE UPPER
LEVEL FLOW WILL BECOME LESS MERIDIONAL THURSDAY AND FRIDAY AS A
TROUGH MOVES THROUGH THE LONG WAVE RIDGE INTO THE WESTERN UNITED
STATES, AND DOWNSLOPE FLOW SHOULD SCOUR OUT THE REMNANTS OF THE
ARCTIC AIR THURSDAY AFTERNOON AND NIGHT. COOLER AIR WILL RETURN NEXT
WEEKEND, BUT THE DETAILS ARE UNCERTAIN. IF THE UPPER LEVEL TROUGH
COMES OUT IN ONE PIECE LIKE THE ECMWF ADVERTISES, THERE WILL BE A
CHANCE FOR LIGHT PRECIPITATION IN WESTERN KANSAS; HOWEVER, THE
WEAKER GFS SOLUTION SEEMS MORE REASONABLE.
ADDITIONAL SURGES OF COLD AIR ARE LIKELY EVERY FEW DAYS UNTIL A MORE
ZONAL FLOW REGIME RETURNS IN EARLY MARCH. THERE IS LITTLE INDICATION
THAT SIGNIFICANT PRECIPITATION IS LIKELY IN THE NEAR FUTURE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI FEB 13 2015
NAM, RAP, AND HRRR WERE ALL IN DECENT AGREEMENT THIS MORNING WILL
MOVING A COLD FRONT ACROSS SOUTHWEST KANSAS BETWEEN 15Z AND 21Z
SATURDAY. AS THIS FRONT PASSES A SOUTHWEST/WESTERLY WIND AT 10
KNOTS OR LESS WILL SHIFT TO THE NORTHEAST AND THEN INCREASE TO
AROUND 20 KNOTS. AT THIS TIME FRONTAL PASSAGE IS EXPECTED AT HAYS
AROUND 15Z AND THEN AT DODGE CITY AND GARDEN CITY AROUND 18Z.
GUSTY WINDS BEHIND THIS FRONT WILL GRADUALLY VEER MORE EASTERLY BY
00Z SUNDAY AND AFTER 03Z SUNDAY DECREASE INTO THE 10 TO 15 KNOT
RANGE. NAM BUFR SOUNDINGS DOES INDICATED SOME INCREASING MOISTURE
IN THE 2000 TO 3000FT AGL LEVEL BEHIND THIS FRONT AFTER 18Z IN
MAINLY THE HAYS AREA SO A PERIOD OF MVFR CEILINGS IS ANTICIPATED
LATER TODAY IN NORTH CENTRAL KANSAS. ELSEWHERE VFR CONDITIONS ARE
EXPECTED THROUGH THE EARLY EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 37 58 15 36 / 0 0 0 0
GCK 32 59 17 40 / 0 0 0 0
EHA 37 69 24 45 / 0 0 0 0
LBL 35 65 20 41 / 0 0 10 0
HYS 33 37 12 31 / 0 0 0 10
P28 34 59 17 31 / 0 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...GERARD
LONG TERM...RUTHI
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
409 AM EST SAT FEB 14 2015
.SYNOPSIS...
HIGH PRESSURE IS POSITIONED OFFSHORE. A STRONG COLD FRONT WILL CROSS
THE AREA THIS AFTERNOON AND EVENING...BRINGING AN ARCTIC BLAST
THROUGH EARLY WEEK. HIGH PRESSURE CROSSES THE AREA MONDAY. LOW
PRESSURE IS EXPTECTED TO TRACK NORTHEAST ACROSS THE DEEP SOUTH
MONDAY NIGHT...MOVING OFF THE NORTH CAROLINA COAST TUESDAY NIGHT
BEFORE TRACKING INTO THE GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 08Z...UPR LOW PRESSURE HEADED HERE THIS AFTERNOON/EVENING IS
CURRENTLY OVER NRN ONTARIO WITH 1001MB SFC LOW NORTH OF LAKE HURON.
THIS SYSTEM WILL SHIFT SE TO PHILLY BY THIS EVENING WITH A POWERFUL
COLD FRONT MOVING SE ACROSS THE CWA THIS AFTERNOON AND EVENING.
AHEAD OF THIS COLD FRONT...ISENTROPIC LIFT LOOKS TO CAUSE SNOW IN
THE NERN MD. CURRENT RETURNS OVER PA THE PRECURSOR. WITH 00Z NAM
CONTINUING 15-18Z LIGHT SNOW FOR GREATER BALTIMORE...DECIDED TO
RAISE A WINTER WEATHER ADVISORY THAT EXTENDS UNTIL MIDNIGHT TO
ACCOUNT FOR SNOW WITH THE COLD FRONT LATE THIS AFTERNOON AND
LINGERING SHOWERS THIS EVENING. PERHAPS HALF INCH THIS
MORNING...THEN AN ADDITIONAL 1-2IN FROM THE SQUALL/SHOWERS.
ELSEWHERE...SWLY FLOW THAT INCREASES TO 20 TO 25 MPH RAISES
TEMPERATURES BRIEFLY ABOVE FREEZING...PERHAPS 40F FOR KCHO.
HIGH RES GUIDANCE SUCH AS HRRR AND NAM NEST FEATURES SQUALL LIKE
SNOW SWATH WITH THE COLD FRONT. BURST OF SNOW AND WIND WILL COME ON
QUICKLY AND POTENTIALLY BE HAZARDOUS AS TEMPERATURES CRASH. ABOVE
FREEZING TEMPERATURES PRIOR TO THE SNOW WILL LIMIT THE IMMEDIATE
IMPACT AND IS WHY THE WINTER WEATHER ADVISORY IS NOT LARGER.
STATEMENT REGARDING THE SNOW AS IT COMES IN SEEMS SUFFICIENT TO
HIGHLIGHT THREATS OF UP TO 1 INCH OF SNOW AND SUBSEQUENT FREEZE UP.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
COLDEST AIR OF THE SEASON FOLLOWS COLD FRONT WITH VERY WINDY
CONDITIONS. HIGH WIND WARNING AND WIND CHILL WARNING FOR MANY
AREA...ADVISORIES ELSEWHERE. TIMING OF WARNINGS WERE BASED ON
ADVISORY CRITERIA. PLEASE SEE NPWLWX AND WSWLWX FOR SPECIFICS WITH
THOSE. HEADLINE DECISIONS BASED ON GFS BASED MOSGUIDE WINDS AND
TEMPERATURES FROM MET/SREF BLEND. CRITERIA FOR WIND CHILL IS -25F
FOR NRN MD AND WEST FROM BLUE RIDGE...-20F EAST. HIGH WIND CRITERIA
IS 58 MPH (50 KNOTS). WIND CHILL HEADLINES GO UNTIL NOON WHEN AN
ADVISORY EXTENSION IS LIKELY INTO SUNDAY NIGHT FOR MUCH OF THE AREA.
WIND HEADLINES DROP NOON OR 2PM SUNDAY...SHOULD COVER THE TIMEFRAME
OF WIND ADVISORY GUSTS.
OTHERWISE SATURDAY EVENING...SNOW TAPERS TO ISOLATED SHOWERS BEHIND
THE COLD FRONT FROM WEST TO EAST. CURRENT THOUGHT IS PRECIP END TIME
OF AROUND 7PM FOR INTERSTATE 95...9PM OR SO FOR THE WRN SHORE OF THE
BAY/SRN MD.
UPSLOPE SNOW BEGINS THIS MORNING AND IS HEAVIEST THIS AFTERNOON...
ADVISORY OUT THERE 10AM TO MIDNIGHT WITH TOTAL ACCUM 3-5 INCHES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SUNDAY NGT WL BE ESPECIALLY COLD AND DRY. I DON`T NRMLY ADDRESS
DWPTS IN THE DSCN....BUT WE ARE LOOKING AT DWPTS OF BTWN -5 AND
-15. I DID A QUICK CHECK OF LAST JAN/FEB DWPTS: AS WE ALL KNOW
LAST JAN/FEB HAD A LOT OF COLD AIR. IN 2014 DC AREA HAD LOWEST
DWPT READING OF -14 IN JAN...AND -11 IN FEB...BUT VALUES THIS LOW
HERE ARE FAIRLY RARE. STATIC ELECTRICITY WL BE HIGH.
AFTR THE XTRMLY STRONG WIND OF SUN THESE WL BE SLOW TO DIMINISH
SUN NGT. THIS WL LKLY LEAD TO MORE WIND CHILL ADVSORIES BEING
NEEDED. THERE IS A PTNL FOR RECORD LOW TEMPS TO BE REACHED - SEE
CLIMATE SXN BLO FOR NUMBERS.
HIGH PRES OVR THE AREA MON. HIGHS SHOULD CLIMB BACK INTO L20S W/
LGTR WINDS.
THE EURO HAS BEEN PERFORMING WELL AS OF LATE - IT HAD TMRW`S STRONG
NEW ENGLAND CSTL LOW PEGGED LAST MON. THERE IS CONCERN ABT THE
FATE OF AN AREA OF LOW PRES COMING FM THE GULF STATES MON NGT. THE
GFS HAS IT OVR GA TUE AFTN...TURNING NE NEAR ORF AND INTENSIFYING
TUE NGT AS IT TRACKS OVR CAPE COD. THE EURO KEEPS IT FURTHER S -
NEAR HAT AT 06Z WED...THEN TAKING A MORE EWD TRACK AND IMPACTING
ATLC CANADA. THE GFS SOLN WOULD BE MORE PROBLEMATIC FOR MID ALTC.
WE ARE CURRENTLY FCSTG A CHC OF SN TUE/TUE NGT...LKLY SE OF DC.
DEPENDING UPON EVENTUAL TRACK THESE MAY BE CHGD.
TEMPS RMNG WELL BLO NRML THRU THE END OF THE WK. HIGHS SHOULD BE
IN THE M40S/LOWS M20S IN MID FEB.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE OFFSHORE WITH RETURN FLOW TODAY...MOISTENING LATE THIS
MORNING WITH BRIEF SNOW/MVFR FOR BALTIMORE AREA ROUGHLY 15-18Z. VERY
STRONG COLD FRONT CROSSES THE TERMINALS EARLY SATURDAY EVENING WITH
SNOW SQUALLS IN THE AFTERNOON/EARLY EVENING FOR DC METROS. NORTHWEST
WINDS OF 30 KT AND GUSTS 45 TO 50 KT. SNOW THREAT ENDS DURING THE
EVENING FOR THE TERMINALS...LINGERING LONGEST FOR BALTIMORE. WINDS
STRENGTHEN OVERNIGHT...AND ONLY SLOW DIMINISH SUNDAY...PERHAPS 35 TO
40 KT GUSTS FOR THE AFTERNOON SUNDAY.
GUSTY WINDS CONT SUN NGT. HIGH PRES OVR THE AREA MON. CLDS MAY
INCRS MON NGT/TUE AS LOW PRES DVLPS OVR THE GULF STATES. DEPENDING
UPON THE STORM TRACK WL DETERMINE IF MID ATLC WL SEE LOWER
CLDS/SNOW TUE AND TUE NGT OR JUST HIGHER CLDS.
&&
.MARINE...
HIGH PRESSURE DRIFTS EAST FROM THE COAST THIS MORNING WITH RETURN
FLOW CHANNELING 20 KT UP THE BAY. SCA NOW FOR SRN MD WATERS...
EXPANDING TO ALL WATERS THIS MORNING AS WIND BECOMES SWLY AND
INCREASES AHEAD OF A VERY STRONG COLD FRONT THAT CROSSES THE WATERS
EARLY THIS EVENING. BRIEF SNOW...BUT MAIN STORY IS 40 TO 50 KT WIND
GUSTS THIS EVENING THROUGH SUNDAY MORNING AND 35 TO 40 KT GUSTS
SUNDAY AFTERNOON. STORM WARNING BEGINS AT 6PM SHARP AND CONTINUES
THROUGH SUNDAY. LIKELY DROPPED FOR A GALE WARNING SUNDAY AFTERNOON
WHICH MAY LINGER INTO THE EVENING...SCA THEN INTO MONDAY.
WINDS MAY BE GALE SUN NGT...OR HIGH END SCA. THESE WL DIMINISH
DURG THE DAY MON...BUT HV THE PTNL TO INCRS AGN TUE THRU WED
DEPENDING ON THE TRACK OF A GULF STATE CSTL LOW. SCA`S MAY BE
NEEDED TUE-WED.
&&
.FIRE WEATHER...
HIGH PRESSURE BUILDING INTO THE REGION SUNDAY WILL BRING AN ENHANCED
FIRE THREAT. NW WINDS WILL GUST BETWEEN 45 AND 55 MPH SUNDAY
MORNING...ONLY DECREASING TO 30 AND 40 MPH SUNDAY AFTN/EVENING.
THE HIGH WILL BRING A VERY COLD AND DRY AIRMASS...RESULTING IN RH
VALUES DROPPING INTO THE 20S ACROSS CENTRAL VA...30S IN
EASTERN/CENTRAL MD...AND 50S WEST OF THE BLUE RIDGE. THE LAST
COMPONENT OF CONCERN IS THE 10 HR FUEL MOISTURE...WHICH CURRENTLY
ARE FORECASTED TO BE JUST BELOW 10 PERCENT. WE`LL MONITOR THE
TREND AND COLLABORATE WITH STATE FIRE SUPERVISORS TO DETERMINE THE
NEED OF A STATEMENT OR WARNING FOR SUNDAY.
&&
.CLIMATE...
VERY COLD AIR WILL MOVE INTO THE REGION SATURDAY NIGHT. HERE ARE
RECORD LOW TEMPERATURES FOR SUNDAY AND MONDAY FOR OUR THREE MAIN
CLIMATE SITES:
RECORD LOW MIN...FEB 15:
BWI...6 (1899/1943)
DCA...-6 (1899)
IAD...7 (1965)
RECORD LOW MAX...FEB 15:
BWI...18 (1943)
DCA...18 (1943)
IAD...22 (1979)
RECORD LOW MIN...FEB 16:
BWI...5 (1905)
DCA...5 (1905)
IAD...11 (1963/1987)
RECORD LOW MAX...FEB 16:
BWI...18 (1904)
DCA...18 (1904)
IAD...22 (2003)
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR DCZ001.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR DCZ001.
MD...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT
EST TONIGHT FOR MDZ006-011-014-501-506>508.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 6 PM EST SUNDAY
FOR MDZ501.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR MDZ003>006-502-503-505-507.
HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR MDZ003>006-011-013-014-016>018-503>508.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR MDZ011-013-014-016>018-504-506-508.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY FOR
MDZ501-502.
VA...HIGH WIND WARNING FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY
FOR VAZ025>027-029-503-504-507-508.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT
EST TONIGHT FOR VAZ503.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 6 PM EST SUNDAY
FOR VAZ503.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR VAZ028-031-504-505-507-508.
HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR VAZ028-030-031-040-051>055-057-501-502-505-506.
WIND ADVISORY FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY FOR
VAZ036>039-050-056.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR VAZ025>027-029-030-036>040-050>057-501-502-506.
WV...HIGH WIND WARNING FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY
FOR WVZ055-505-506.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT
EST TONIGHT FOR WVZ501-503-505.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 6 PM EST SUNDAY
FOR WVZ501-503-505.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY
FOR WVZ050>053-055-502-504-506.
HIGH WIND WARNING FROM 6 PM THIS EVENING TO 2 PM EST SUNDAY
FOR WVZ051>053.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO NOON EST SUNDAY FOR
WVZ050-501>504.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR
ANZ532>534-537-540>543.
STORM WARNING FROM 6 PM THIS EVENING TO 6 PM EST SUNDAY FOR
ANZ530>543.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST THIS
EVENING FOR ANZ530-531-535-536-538-539.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
359 AM EST SAT FEB 14 2015
.SYNOPSIS...
HIGH PRESSURE IS POSITIONED OFFSHORE. A STRONG COLD FRONT WILL CROSS
THE AREA THIS AFTERNOON AND EVENING...BRINGING AN ARCTIC BLAST
THROUGH EARLY WEEK. HIGH PRESSURE CROSSES THE AREA MONDAY. LOW
PRESSURE IS EXPTECTED TO TRACK NORTHEAST ACROSS THE DEEP SOUTH
MONDAY NIGHT...MOVING OFF THE NORTH CAROLINA COAST TUESDAY NIGHT
BEFORE TRACKING INTO THE GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 08Z...UPR LOW PRESSURE HEADED HERE THIS AFTERNOON/EVENING IS
CURRENTLY OVER NRN ONTARIO WITH 1001MB SFC LOW NORTH OF LAKE HURON.
THIS SYSTEM WILL SHIFT SE TO PHILLY BY THIS EVENING WITH A POWERFUL
COLD FRONT MOVING SE ACROSS THE CWA THIS AFTERNOON AND EVENING.
AHEAD OF THIS COLD FRONT...ISENTROPIC LIFT LOOKS TO CAUSE SNOW IN
THE NERN MD. CURRENT RETURNS OVER PA THE PRECURSOR. WITH 00Z NAM
CONTINUING 15-18Z LIGHT SNOW FOR GREATER BALTIMORE...DECIDED TO
RAISE A WINTER WEATHER ADVISORY THAT EXTENDS UNTIL MIDNIGHT TO
ACCOUNT FOR SNOW WITH THE COLD FRONT LATE THIS AFTERNOON AND
LINGERING SHOWERS THIS EVENING. PERHAPS HALF INCH THIS
MORNING...THEN AN ADDITIONAL 1-2IN FROM THE SQUALL/SHOWERS.
ELSEWHERE...SWLY FLOW THAT INCREASES TO 20 TO 25 MPH RAISES
TEMPERATURES BRIEFLY ABOVE FREEZING...PERHAPS 40F FOR KCHO.
HIGH RES GUIDANCE SUCH AS HRRR AND NAM NEST FEATURES SQUALL LIKE
SNOW SWATH WITH THE COLD FRONT. BURST OF SNOW AND WIND WILL COME ON
QUICKLY AND POTENTIALLY BE HAZARDOUS AS TEMPERATURES CRASH. ABOVE
FREEZING TEMPERATURES PRIOR TO THE SNOW WILL LIMIT THE IMMEDIATE
IMPACT AND IS WHY THE WINTER WEATHER ADVISORY IS NOT LARGER.
STATEMENT REGARDING THE SNOW AS IT COMES IN SEEMS SUFFICIENT TO
HIGHLIGHT THREATS OF UP TO 1 INCH OF SNOW AND SUBSEQUENT FREEZE UP.
COLDEST AIR OF THE SEASON FOLLOWS COLD FRONT WITH VERY WINDY
CONDITIONS. HIGH WIND WARNING AND WIND CHILL WARNING FOR MANY
AREA...ADVISORIES ELSEWHERE. TIMING OF WARNINGS WERE BASED ON
ADVISORY CRITERIA. PLEASE SEE NPWLWX AND WSWLWX FOR SPECIFICS WITH
THOSE. HEADLINE DECISIONS BASED ON GFS BASED MOSGUIDE WINDS AND
TEMPERATURES FROM MET/SREF BLEND. CRITERIA FOR WIND CHILL IS -25F
FOR NRN MD AND WEST FROM BLUE RIDGE...-20F EAST. HIGH WIND CRITERIA
IS 58 MPH (50 KNOTS). WIND CHILL HEADLINES GO UNTIL NOON WHEN AN
ADVISORY EXTENSION IS LIKELY INTO SUNDAY NIGHT FOR MUCH OF THE AREA.
WIND HEADLINES DROP NOON OR 2PM SUNDAY...SHOULD COVER THE TIMEFRAME
OF WIND ADVISORY GUSTS.
OTHERWISE SATURDAY EVENING...SNOW TAPERS TO ISOLATED SHOWERS BEHIND
THE COLD FRONT FROM WEST TO EAST. CURRENT THOUGHT IS PRECIP END TIME
OF AROUND 7PM FOR INTERSTATE 95...9PM OR SO FOR THE WRN SHORE OF THE
BAY/SRN MD.
UPSLOPE SNOW BEGINS THIS MORNING AND IS HEAVIEST THIS AFTERNOON...
ADVISORY OUT THERE 10AM TO MIDNIGHT WITH TOTAL ACCUM 3-5 INCHES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SUNDAY NGT WL BE ESPECIALLY COLD AND DRY. I DON`T NRMLY ADDRESS
DWPTS IN THE DSCN....BUT WE ARE LOOKING AT DWPTS OF BTWN -5 AND
-15. I DID A QUICK CHECK OF LAST JAN/FEB DWPTS: AS WE ALL KNOW
LAST JAN/FEB HAD A LOT OF COLD AIR. IN 2014 DC AREA HAD LOWEST
DWPT READING OF -14 IN JAN...AND -11 IN FEB...BUT VALUES THIS LOW
HERE ARE FAIRLY RARE. STATIC ELECTRICITY WL BE HIGH.
AFTR THE XTRMLY STRONG WIND OF SUN THESE WL BE SLOW TO DIMINISH
SUN NGT. THIS WL LKLY LEAD TO MORE WIND CHILL ADVSORIES BEING
NEEDED. THERE IS A PTNL FOR RECORD LOW TEMPS TO BE REACHED - SEE
CLIMATE SXN BLO FOR NUMBERS.
HIGH PRES OVR THE AREA MON. HIGHS SHOULD CLIMB BACK INTO L20S W/
LGTR WINDS.
THE EURO HAS BEEN PERFORMING WELL AS OF LATE - IT HAD TMRW`S STRONG
NEW ENGLAND CSTL LOW PEGGED LAST MON. THERE IS CONCERN ABT THE
FATE OF AN AREA OF LOW PRES COMING FM THE GULF STATES MON NGT. THE
GFS HAS IT OVR GA TUE AFTN...TURNING NE NEAR ORF AND INTENSIFYING
TUE NGT AS IT TRACKS OVR CAPE COD. THE EURO KEEPS IT FURTHER S -
NEAR HAT AT 06Z WED...THEN TAKING A MORE EWD TRACK AND IMPACTING
ATLC CANADA. THE GFS SOLN WOULD BE MORE PROBLEMATIC FOR MID ALTC.
WE ARE CURRENTLY FCSTG A CHC OF SN TUE/TUE NGT...LKLY SE OF DC.
DEPENDING UPON EVENTUAL TRACK THESE MAY BE CHGD.
TEMPS RMNG WELL BLO NRML THRU THE END OF THE WK. HIGHS SHOULD BE
IN THE M40S/LOWS M20S IN MID FEB.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
GUSTY WINDS CONT SUN NGT. HIGH PRES OVR THE AREA MON. CLDS MAY
INCRS MON NGT/TUE AS LOW PRES DVLPS OVR THE GULF STATES. DEPENDING
UPON THE STORM TRACK WL DETERMINE IF MID ATLC WL SEE LOWER
CLDS/SNOW TUE AND TUE NGT OR JUST HIGHER CLDS.
&&
.MARINE...
WINDS MAY BE GALE SUN NGT...OR HIGH END SCA. THESE WL DIMINISH
DURG THE DAY MON...BUT HV THE PTNL TO INCRS AGN TUE THRU WED
DEPENDING ON THE TRACK OF A GULF STATE CSTL LOW. SCA`S MAY BE
NEEDED TUE-WED.
&&
.FIRE WEATHER...
HIGH PRESSURE BUILDING INTO THE REGION SUNDAY WILL BRING AN ENHANCED
FIRE THREAT. NW WINDS WILL GUST BETWEEN 45 AND 55 MPH SUNDAY
MORNING...ONLY DECREASING TO 30 AND 40 MPH SUNDAY AFTN/EVENING.
THE HIGH WILL BRING A VERY COLD AND DRY AIRMASS...RESULTING IN RH
VALUES DROPPING INTO THE 20S ACROSS CENTRAL VA...30S IN
EASTERN/CENTRAL MD...AND 50S WEST OF THE BLUE RIDGE. THE LAST
COMPONENT OF CONCERN IS THE 10 HR FUEL MOISTURE...WHICH CURRENTLY
ARE FORECASTED TO BE JUST BELOW 10 PERCENT. WE`LL MONITOR THE
TREND AND COLLABORATE WITH STATE FIRE SUPERVISORS TO DETERMINE THE
NEED OF A STATEMENT OR WARNING FOR SUNDAY.
&&
.CLIMATE...
VERY COLD AIR WILL MOVE INTO THE REGION SATURDAY NIGHT. HERE ARE
RECORD LOW TEMPERATURES FOR SUNDAY AND MONDAY FOR OUR THREE MAIN
CLIMATE SITES:
RECORD LOW MIN...FEB 15:
BWI...6 (1899/1943)
DCA...-6 (1899)
IAD...7 (1965)
RECORD LOW MAX...FEB 15:
BWI...18 (1943)
DCA...18 (1943)
IAD...22 (1979)
RECORD LOW MIN...FEB 16:
BWI...5 (1905)
DCA...5 (1905)
IAD...11 (1963/1987)
RECORD LOW MAX...FEB 16:
BWI...18 (1904)
DCA...18 (1904)
IAD...22 (2003)
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
DCZ001.
MD...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR MDZ501.
HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
MDZ003>006-011-013-014-016>018-501>508.
WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
MDZ003>006-501>503-505-507.
VA...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR VAZ503.
HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
VAZ025>031-036>040-050>057-501>508.
WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
VAZ025>031-503>505-507-508.
WV...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT EST
TONIGHT FOR WVZ501-503-505.
HIGH WIND WATCH FROM THIS EVENING THROUGH SUNDAY MORNING FOR
WVZ050>053-055-501>506.
WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
WVZ050>053-055-501>506.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR
ANZ532>534-537-540>543.
STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR
ANZ530>543.
SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST THIS
EVENING FOR ANZ530-531-535-536-538-539.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
912 PM MST FRI FEB 13 2015
.UPDATE...
JUST SOME MINOR FORECAST ADJUSTMENTS FOR THE UPDATE THIS EVENING.
DEWPOINT GRADIENT AND ONSET OF LOW CLOUDS PLACED THE BACKDOOR COLD
FRONT OVER W ND/FAR NE MT AT 04Z. RADAR SHOWED PRECIPITATION WAS
BACK OVER CENTRAL ND. OBSERVATIONS SHOWED MID CLOUDS WILL ARRIVE
OVER THE EASTERN ZONES BEFORE LOW CLOUDS MOVE IN...SO DESPITE SOME
EXPECTED HIGHER HUMIDITIES IN THE E...WILL LEAVE OUT MENTION OF
FOG. WILL KEEP AREA DRY OVERNIGHT AS WELL. RAISED TEMPERATURES
FROM KBIL W AS 850 MB TEMPERATURES WILL BE SIMILAR TO THIS
MORNING/S READINGS BY 12Z SAT...AND CIRRUS WILL ALSO HOLD
TEMPERATURES UP. IN ADDITION...CURRENT READINGS WERE IN THE 40S
AND 50S. MADE SLIGHT ADJUSTMENTS TO WINDS AND SKY COVER BASED ON
LATEST OBSERVED AND MODEL TRENDS.
SAT CONTINUED TO LOOK MAINLY DRY AND WARM AS BACKDOOR FRONT
PUSHES BACK TO THE E. SHORTWAVES IN NW FLOW WILL BRING INCREASING
CHANCES FOR PRECIPITATION TO THE AREA SAT NIGHT THROUGH SUN NIGHT
AS WELL AS A COOLER AIRMASS. ARTHUR
&&
.SHORT TERM...VALID FOR SAT AND SUN...
...AFTER A VERY PLEASANT AND WARM DAY TODAY...THE WEATHER WILL GET
MORE INTERESTING BY THE END OF THE HOLIDAY WEEKEND...
DAYTIME HIGH TEMPERATURES THIS AFTERNOON ARE APPROACHING NEAR
RECORD VALUES DUE TO STRONG MIXING IN THE LOWER PORTIONS OF THE
ATMOSPHERE. 1 PM TEMPERATURES ACROSS THE REGION WERE GENERALLY IN THE
UPPER 50S AND LOWER 60S AND ON THE RISE DUE TO FAIRLY PERSISTENT
SURFACE WINDS.
BY TONIGHT...MODELS ARE IN GOOD AGREEMENT IN BRINGING A BACK DOOR
COLD FRONT WITH THE AIR BEHIND IT ORIGINATING FROM SOUTHERN
SASKATCHEWAN AND MANITOBA. THERE IS NOT ANY DOUBT IT WILL GET
COOLER IN THE OUR FAR EASTERN ZONES...BUT THERE IS UNCERTAINTY IN HOW
FAR WEST THE COLD AIR WILL ACTUALLY GET. THERE IS A CHANCE SOME
LOCATIONS OUT EAST...BAKER...EKALAKA...COULD SEE HIGHS HOVERING
AROUND 30 DEGREES TOMORROW...WHILE OTHER LOCATIONS SUCH AS
BILLINGS SEE HIGHS WELL INTO THE 50S. WINDS WILL SHIFT EASTERLY
WITH THE ONSET OF THIS BAROCLINIC ZONE...AND BRING SOME CLOUD
COVER WITH IT. HRRR BUFKIT SOUNDING ANALYSIS SUGGESTS THE EASTERLY
FLOW WILL BRING DIMINISHED VISIBILITIES TO KMLS AND KBHK BY
SATURDAY MORNING. HOWEVER...THE COLDEST AIR WILL REMAIN WELL TO
THE NORTH AND EAST OF THE BILLINGS CWA.
FOR SATURDAY NIGHT INTO SUNDAY...THINGS GET A LITTLE MORE
INTERESTING AS THE AFOREMENTIONED LINGERING FRONT INTERACTS WITH
AN UPPER LEVEL SHORTWAVE MOVING IN FROM THE NORTHWEST. THE MAIN
IMPACT WILL NOW TURN TO SNOW ACCUMULATIONS IN THE BEARTOOTH
FOOTHILLS. BUFKIT SOUNDING ANALYSIS HINTS AT A BRIEF PERIOD OF
UPSLOPE FLOW ACCOMPANIED WITH A FAIRLY UNSTABLE AIR MASS BY
TOMORROW AFTERNOON...WHICH COULD GENERATE SEVERAL INCHES OF SNOW
FOR AREAS NEAR NYE AND RED LODGE. TAKING A LOOK AT THE CIPS
ANALOGS FOR SIMILAR CASES...IT FURTHER BACKS THE THEORY THAT THE
FOOTHILL LOCATIONS ARE THE PREFERRED AREA FOR POTENTIAL
ACCUMULATING SNOW. EITHER WAY...DECIDED TO HOLD OFF ON ISSUANCE
OF A WINTER WEATHER ADVISORY AT THIS FORECAST PACKAGE...AS AMOUNTS
ARE STILL NOT SOLIDIFIED AT THIS TIME. WOULD GUESS ANYWHERE FROM
3-6 INCHES IS POSSIBLE WHEN ALL IS SAID AND DONE. SINGER
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
EXTENDED PERIOD BEGINS ON MONDAY WITH THE NOSE OF A STRONG UPPER
LEVEL JET DIVING INTO NORTHERN IDAHO. DURING THE DAYS TO
FOLLOW...THIS JET STREAK WILL SLIDE TO THE EAST AND ASSIST THE
PROGRESSION OF A SERIES OF SHORTWAVES THROUGH THE REGION. THERE
REMAINS THE POTENTIAL FOR SOME ACCUMULATING SNOW IN BOTH THE BIG
HORN AND BEARTOOTH RANGES...AS THE ORIENTATION OF THE MAIN UPPER
LEVEL FORCING FAVORS THOSE PARTICULAR AREAS THE MOST.
AFTER A BRIEF COOLDOWN EARLY IN THE WEEK...TEMPERATURES WILL
AGAIN BECOME SOMEWHAT MILD AFTER MONDAY. THE FORECAST REMAINS
UNCERTAIN AFTER THAT...SO LEFT THE REMAINING FORECAST AS IS UNTIL
MODELS COME INTO BETTER AGREEMENT. SINGER
&&
.AVIATION...
MVFR TO IFR CONDITIONS DUE TO LOW CEILINGS WILL MOVE INTO AREAS
FROM KMLS E AND SE OVERNIGHT AND CONTINUE THROUGH EARLY SAT
MORNING. PATCHY FOG IS ALSO POSSIBLE IN THESE AREAS. OTHERWISE...VFR
WILL PREVAIL ACROSS THE AREA THROUGH SAT EVENING. MOUNTAIN
OBSCURATIONS WILL INCREASE SAT EVENING. ARTHUR
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 038/059 034/042 027/036 018/037 024/043 028/049 031/046
01/E 25/W 54/J 32/J 11/B 11/B 22/J
LVM 045/051 034/039 026/036 018/040 023/048 029/049 032/048
01/N 34/W 53/J 21/B 11/N 11/N 22/J
HDN 033/053 029/043 024/035 013/034 018/041 023/049 026/045
01/E 24/W 44/J 32/J 22/W 11/B 22/W
MLS 028/038 024/042 021/030 009/026 015/036 019/042 024/040
12/W 21/E 33/J 21/B 22/J 11/B 22/J
4BQ 029/043 027/040 023/033 013/028 017/039 020/047 026/043
12/W 21/E 34/J 31/B 22/W 11/B 22/J
BHK 016/024 017/036 020/027 005/021 010/032 017/038 021/037
12/J 21/N 34/J 21/B 22/J 11/E 12/J
SHR 029/054 029/040 023/032 013/031 016/040 020/047 025/043
01/B 33/W 55/J 42/J 22/W 21/B 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
443 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND WIND CHILLS IS A LIFE
THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED FROM THE
SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM MOVES ACROSS THE REGION...WHICH WILL BE FOLLOWED BY
STRONG WINDS AND ARCTIC AIR. THIS SYSTEM SHOULD ENTER FAR WESTERN
NEW YORK LATE THIS MORNING. UNTIL THEN...EXPECT A GENERAL LIGHT
SNOWFALL WHICH WILL INCREASE IN INTENSITY A BIT TOWARD LAKE MORNING
AS MOISTURE AND SURFACE CONVERGENCE INCREASE AHEAD OF THIS LOW.
THROUGH NOON TODAY...EXPECT 1 TO 3 INCHES OF SNOW IN THE BUFFALO
AREA AND LOCATIONS WEST WITH AN INCH OR LESS ROCHESTER EASTWARD.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING RAPIDLY
AS IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL INCREASE
RAPIDLY WITH THE PASSAGE OF THIS LOW...AND WITH THIS EXPECT A QUICK
BURST OF SNOW. NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW. A HRRR WEIGHTED CONSENSUS OF MESOSCALE GUIDANCE BRINGS
THIS INTO BUF-JHW AROUND NOON AND ROC-ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE SURFACE WIND SHIFT...THERE WILL BE A
SMALL AREA OF UPPER LEVEL DIFFLUENCE WITH THE 500 MB LOW WHICH TRAILS
THE SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
THE FORECAST USING A CONSENSUS WHICH BRINGS ENHANCED SNOWFALL TO THE
FINGER LAKES REGION INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO LOCALLY ENHANCED SNOWFALL RATES AND
PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE WITH GUSTY
SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...A
REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS. THIS SHOULD
ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE ONTARIO...WITH AMPLE
MOISTURE BENEATH THE BACK OF THE UPPER LOW LIKELY TO OFFSET THE
STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND CHILLS WILL
COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST DANGEROUS
CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25 TO 35 BELOW
LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS AND MOST
SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE ONTARIO WHERE
NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
ONE OF THE COLDEST DAYS IN DECADES WILL START THIS TIME PERIOD AS A
LOBE OF -25C TO -27C AIR AT 850 HPA REMAINS ACROSS THE REGION...WITH A
BITING NORTHWEST WIND. TO ADD TO THE EXTREME BITTERNESS...SNOW
SHOWERS WILL BE FALLING THROUGH THE DAY SOUTH OF LAKE ONTARIO.
FOR THE EXTREME TEMPERATURES...
SUNDAY NORTHWEST WINDS WILL CONTINUE TO BRING A FRESH COLD AIRMASS
ACROSS OUR REGION...WITH -25C TO -27C 850 HPA TEMPERATURES AND CAA
ADVECTION THROUGH THE DAY BRINGING -25C AIR AS LOW AS JUST A FEW
HUNDRED FEET ABOVE THE SURFACE. NAEFS MEAN TEMPERATURE AND RETURN
INTERVALS GIVE THIS 850 HPA TEMPERATURES AT LEAST A ONCE IN 10 YEAR
OCCURRENCE. GIVEN THAT TEMPERATURES OF -26C OR LOWER HAVE BEEN
MEASURED ONLY 12 TIMES IN THE MONTH OF FEBRUARY VIA BUFFALO BALLOON
SOUNDINGS (TAKEN TWICE A DAY) SINCE 1948...WE ALSO VERIFY THAT THIS
AIRMASS OCCURS ABOUT ONCE EVERY DECADE OR SO. IN FACT THE COLDEST
850 HPA TEMPERATURE MEASURED VIA BUFFALO BALLOON SOUNDING (TAKEN AT
12Z AND 00Z) IN THE MONTH OF FEBRUARY IS -27.8C BACK ON 12Z FEBRUARY
1, 1971.
THE ARCTIC AIRMASS WILL CONTINUE THE SUBFREEZING TEMPERATURES
THROUGH THE DAY ON SUNDAY...WITH DAYLIGHT HIGHS 0F TO -5F ACROSS THE LAKE
PLAINS AND DOWN TO THE NEGATIVE TEENS IN THE SOUTHERN TIER AND UPON
THE TUG HILL REGION. THESE SUBFREEZING TEMPERATURES WILL ONLY DIP
FARTHER DOWN SUNDAY NIGHT AS HIGH PRESSURE FROM THE CENTRAL GREAT
LAKES BUILDS TOWARDS THE REGION. AS SKIES CLEAR AWAY FROM THE
SOUTHERN LAKE ONTARIO SHORELINE...AND WINDS BECOME LIGHT AND
VARIABLE...SURFACE AIR TEMPERATURES OVER A FRESH AND DEEP SNOWPACK
WILL PLUMMET TO NEAR 10 BELOW ACROSS THE LAKE PLAINS...WITH
WIDESPREAD -20S IN THE SOUTHERN TIER AND PERHAPS AS LOW AS -30F
BELOW IN THE NORTH COUNTRY...INCLUDING THE WATERTOWN AIRPORT. THESE
AIR TEMPERATURES LATE SUNDAY NIGHT AND EARLY MONDAY MORNING WILL
DROP TO NEAR RECORD LEVELS FOR THE DATE OF FEBRUARY 16TH. PLEASE SEE
CLIMATE SECTION BELOW FOR VALUES.
FOR THESE SUNDAY NIGHT TEMPERATURES TO COME TO FRUITION...OUR WINDS
MUST BE LIGHT...AND A LIGHT WIND WILL ONLY NUDGE WIND CHILLS LOWER.
WIND CHILLS SUNDAY NIGHT WILL RANGE FROM -25 TO -35 BELOW...AND
ADDITIONAL HEADLINES WILL LIKELY BE NEEDED SUNDAY NIGHT FOR THESE
VERY LOW WIND CHILLS. IF WINDS WERE TO REMAIN STEADY AROUND 10
MPH...OVERNIGHT LOWS WILL LIKELY NOT BE AS LOW...THOUGH WITH THE
STRONGER WINDS WIND CHILLS VALUES WILL STILL BE IN THE -25 TO -35
BELOW RANGE.
MONDAY HIGH PRESSURE WILL ADVANCE ACROSS THE EASTERN GREAT LAKES
REGION. WARMING ALOFT WITH 850 HPA TEMPERATURES RISING TO THE
NEGATIVE TEENS WILL ALLOW FOR MANY AREAS TO RISE ABOVE 0F FOR A FEW
HOURS. THE LIGHT WINDS AND VERY LOW MIXING HEIGHTS WILL PROBABLY
KEEP MOST AREAS BELOW 5F THOUGH.
AS THIS HIGH PRESSURE SCOOTS EASTWARD MONDAY NIGHT A LIGHT SOUTHERLY
FLOW WILL DEVELOP...FIRST ACROSS WESTERN NEW YORK AND LATER ACROSS
THE NORTH COUNTRY. MOST AREAS ACROSS WNY WILL DROP BACK TO NEAR
0F...WHICH IS NOT MUCH OF A DROP CONSIDERING DAYTIME HIGHS WILL ONLY
BE IN THE LOW SINGLE DIGITS DURING THE DAYTIME. TO THE EAST WHERE
THE SOUTHERLY FLOW WILL DEVELOP LATER OVERNIGHT TEMPERATURES WILL
LIKELY DROP 5 TO PERHAPS 10 DEGREES BELOW ZERO. MID AND HIGH LEVEL
CLOUDS WILL BEGIN TO REACH THE REGION LATE OVERNIGHT...WHICH WILL
ALSO AID IN MAINTAINING LOWS NOT AS HARSH AS THE PRIOR NIGHT.
FOR THE SNOWFALL...
SUNDAY SNOW WILL CONTINUE TO FALL ACROSS THE REGION. ALOFT WEAK
ISENTROPIC UPGLIDE WILL BE PRESENTING ENOUGH LIFT TO GENERATE SNOW
SHOWERS...ACROSS THE TUG HILL EAST OF LAKE ONTARIO...AS WELL AS
AREAS SOUTH OF LAKE ONTARIO. THIS UPGLIDE...SEEN AT THE VERY LOW
255K SURFACE...WILL CONTINUE LIGHT SYNOPTIC SNOW SHOWERS INTO SUNDAY
NIGHT BEFORE THE ISENTROPIC SURFACE FLATTENS WITH THE APPROACHING
AREA OF HIGH PRESSURE.
WITHIN THIS SYNOPTIC SNOW WILL BE BANDS OF HEAVIER SNOWFALL ALONG
THE SOUTHERN LAKE ONTARIO SHORELINE. THIS CURRENT COLD AIRMASS HAS
LIKELY SHRUNK THE OPEN WATERS ON LAKE ONTARIO TO WELL LESS THAN 50
PERCENT...BUT THERE SHOULD STILL BE ENOUGH OPEN WATERS AND THERMAL
HEAT FLUX THROUGH THE THIN ICE TO CREATE LOW LEVEL INSTABILITY AND
ALLOW FOR LAKE EFFECT SNOW SHOWERS TO FALL. A LACKING SNOW CRYSTAL
GROWTH ZONE WILL LIKELY KEEP SNOWFLAKES TO THE SMALL SCALE...WITH 1
TO 2 INCHES OF ADDITIONAL SNOW SUNDAY...DROPPING TO AROUND AN INCH
OVERNIGHT AS LAKE EFFECT SNOWS BECOME THE DOMINATE CHARACTERISTIC OF
THE SNOW...AND EVEN THIS ACTIVITY WILL BE WANING THROUGH THE NIGHT
AS HIGH PRESSURE AND DRIER AIR ADVANCES TOWARDS THE REGION. BACKING
WINDS WILL BRING THESE NOW WEAKEN BANDS OF SNOW TOWARDS SOUTHEAST
AND THEN EAST OF LAKE ONTARIO MONDAY NIGHT WITH ACTIVITY LIKELY
ENDED BY THE END OF MONDAY NIGHT.
BLOWING SNOW WILL STILL BE A MAJOR CONCERN SUNDAY AS NORTHWEST WINDS
CONTINUE THE BLOWING AND DRIFTING OF SNOW ACROSS ROADWAYS. OPEN
AREAS SOUTH OF LAKE ONTARIO WILL EXPERIENCE VERY LOW VISIBILITIES AT
TIMES AS WINDS GUST 30 TO 35 MPH. THESE GUSTS WILL BE LOWER TOWARDS
THE STATE LINE...AND THE MORE FORESTED SOUTHERN TIER WILL LOWER
THE BLOWING AND DRIFTING OF SNOW.
FOR THE NORTH COUNTRY THE BEST CHANCES FOR SNOW WILL COME SUNDAY
WITH THE ISENTROPIC UPGLIDE FLOW. AFTER THIS...THE REGION WILL
LIKELY REMAIN DRY THROUGH THIS TIME PERIOD...WITH MAINLY CLEAR
SKIES.
A CLIMATE NOTE...OUR THREE MAIN CLIMATE SITES (BUFFALO, ROCHESTER,
WATERTOWN) ALL CONSIDER A CLIMATE DAY FROM MIDNIGHT TO MIDNIGHT.
THUS IF AIR TEMPERATURES ARE STILL ABOVE ZERO AT MIDNIGHT LEADING
INTO SUNDAY THESE ABOVE ZERO AIR TEMPERATURES WILL BE CONSIDERED THE
HIGH FOR THE DAY...EVEN IF THE DAYLIGHT HOURS SUNDAY REMAIN WELL
BELOW ZERO. FOR SUNDAY...IT APPEARS MUCH OF THE REGION MAY REMAIN
ABOVE ZERO AT MIDNIGHT...AND THUS THESE VALUES WILL BE THE OFFICIAL
HIGH TEMPERATURES FOR SUNDAY.
ADDITIONAL TEMPERATURE STATS WILL BE FOUND BELOW IN THE CLIMATE
SECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO NEW ENGLAND
THROUGH WEDNESDAY. THE 00Z GFS CONTINUES TO REMAIN FARTHER WESTWARD
WITH THIS SYSTEM AND ITS TRACK THAN THE 00Z ECMWF. FOR NOW WILL
CONTINUE WITH CHANCES POPS. REGARDLESS OF THE TRACK ANOTHER ROUND OF
COLD AIR WILL FOLLOW BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH
FRIDAY...WITH THE POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT
OFF OF LAKE ONTARIO. WHILE THE NEXT ROUND OF COLD DOES NOT APPEAR AS
POTENT AS THE CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP
TEMPERATURES WELL BELOW NORMAL.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
WARM ADVECTION AND MOISTURE WILL INCREASE THIS MORNING AHEAD OF AN
APPROACHING ARCTIC FRONT...AND CONSEQUENTLY LIGHT SNOW SHOWERS WILL
ALSO DEVELOP FROM WEST TO EAST. EXPECT VARIABLE CONDITIONS THROUGH
15Z IN AND OUT OF STEADIER SNOW SHOWERS.
LATER THIS MORNING AND INTO THIS AFTERNOON LOW LEVEL CONVERGENCE AND
LIFT WILL DRAMATICALLY INCREASE WITH THE APPROACH AND PASSAGE OF THE
ARCTIC COLD FRONT...AND WILL ALSO COINCIDE WITH A PERIOD OF
IMPRESSIVE INSTABILITY. THIS WILL LIKELY LEAD TO A BRIEF BURST OF
INTENSE SNOW THAT WILL SWEEP ACROSS THE REGION...WHICH WILL BE
FURTHER COMPLICATED BY INCREASING WINDS WHICH SHOULD PRODUCE
CONSIDERABLE BLOWING AND DRIFTING SNOW. ALL OF THIS SHOULD LEAD TO A
SHORT PERIOD OF VLIFR/LIFR CONDITIONS ACCOMPANYING THE FRONTAL
PASSAGE...WITH CONDITIONS THEN IMPROVING BACK TO IFR/MVFR IN ITS
WAKE.
TONIGHT...EXPECT FAIRLY WIDESPREAD SNOW/SNOW SHOWERS TO PERSIST...
ALONG WITH IFR/LOW-END MVFR CONDITIONS.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.CLIMATE...
A FEW TEMPERATURE CLIMATE STATS BELOW...
DAILY RECORDS:
SUNDAY, FEBRUARY 15TH
MINIMUM LOW MAXIMUM
BUFFALO -16F (1943) 4F (1943)
ROCHESTER -14F (1943) 4F (1943)
WATERTOWN -30F (1987) 1F (1987)
MONDAY, FEBRUARY 16TH
MINIMUM LOW MAXIMUM
BUFFALO -8F (1904) 0F (1904)
ROCHESTER -7F (2004) -1F (1904)
WATERTOWN -24F (1963) 2F (2003)
ONE WAY TO VIEW THIS UPCOMING COLD OUTBREAK IS TO LOOK AT AVERAGE
TEMPERATURES FOR A DAY (AVERAGE OF MAXIMUM AND MINIMUM TEMPERATURE
FOR THE DAY).
LAST TIME A CLIMATE SITE HAD AN AVERAGE TEMPERATURE BELOW ZERO...
BUFFALO JANUARY 19, 1994 HIGH: -1 LOW: -10 AVERAGE: -5.5F
ROCHESTER JANUARY 14, 2004 HIGH: 4 LOW: -6 AVERAGE: -1.0F
RECENT TIMES A CLIMATE SITE HAD A MINIMUM TEMPERATURE MINUS TEN
OR LOWER...
BUFFALO JANUARY 6, 1996 LOW: -10F
JANUARY 19, 1994 LOW: -10F
JANUARY 21, 1985 LOW: -10F
JANUARY 16, 1984 LOW: -10F
JANUARY 17, 1982 LOW: -16F
ROCHESTER JANUARY 21, 2005 LOW: -10F
JANUARY 10, 2004 LOW: -12F
JANUARY 31, 1994 LOW: -10F
JANUARY 19, 1994 LOW: -11F
JANUARY 16, 1994 LOW: -17F
THOUGH THE POSSIBILITY OF A HIGH TEMPERATURE REMAINING BELOW ZERO
FOR A 24-HR DAY PERIOD IS NOW LESS LIKELY HERE ARE THE LAST TIME
CLIMATE SITES DID ACHIEVE THIS FEAT.
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL/JJR
MARINE...APFFEL
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
433 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND WIND CHILLS IS A LIFE
THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED FROM THE
SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM MOVES ACROSS THE REGION...WHICH WILL BE FOLLOWED BY
STRONG WINDS AND ARCTIC AIR. THIS SYSTEM SHOULD ENTER FAR WESTERN
NEW YORK LATE THIS MORNING. UNTIL THEN...EXPECT A GENERAL LIGHT
SNOWFALL WHICH WILL INCREASE IN INTENSITY A BIT TOWARD LAKE MORNING
AS MOISTURE AND SURFACE CONVERGENCE INCREASE AHEAD OF THIS LOW.
THROUGH NOON TODAY...EXPECT 1 TO 3 INCHES OF SNOW IN THE BUFFALO
AREA AND LOCATIONS WEST WITH AN INCH OR LESS ROCHESTER EASTWARD.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING RAPIDLY
AS IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL INCREASE
RAPIDLY WITH THE PASSAGE OF THIS LOW...AND WITH THIS EXPECT A QUICK
BURST OF SNOW. NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW. A HRRR WEIGHTED CONSENSUS OF MESOSCALE GUIDANCE BRINGS
THIS INTO BUF-JHW AROUND NOON AND ROC-ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE SURFACE WIND SHIFT...THERE WILL BE A
SMALL AREA OF UPPER LEVEL DIFFLUENCE WITH THE 500 MB LOW WHICH TRAILS
THE SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
THE FORECAST USING A CONSENSUS WHICH BRINGS ENHANCED SNOWFALL TO THE
FINGER LAKES REGION INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO LOCALLY ENHANCED SNOWFALL RATES AND
PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE WITH GUSTY
SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...A
REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS. THIS SHOULD
ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE ONTARIO...WITH AMPLE
MOISTURE BENEATH THE BACK OF THE UPPER LOW LIKELY TO OFFSET THE
STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND CHILLS WILL
COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST DANGEROUS
CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25 TO 35 BELOW
LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS AND MOST
SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE ONTARIO WHERE
NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
UPDATE COMING SOON FOR SUNDAY AND SUNDAY NIGHT COMING SOON.
BY MONDAY/MONDAY NIGHT...LAKE EFFECT SNOWS WILL LINGER SOUTHEAST OF
LAKE ONTARIO...WITH HIGH TEMPERATURES GETTING INTO THE SINGLE DIGITS
ON MONDAY AND THEN BACK TO +/- ZERO BY MONDAY NIGHT.
A FEW CLIMATE STATS BELOW...
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
ADDITIONALLY...
NUMBER OF DAYS THAT REMAIN BELOW ZERO IN HISTORY
BUFFALO...12 DAYS (145 YEARS OF RECORD)
ROCHESTER...10 DAYS (145 YEARS OF RECORD)
WATERTOWN...38 DAYS (66 YEARS OF RECORD)
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
MONDAY NIGHT AND TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO
NEW ENGLAND THROUGH WEDNESDAY. ANOTHER ROUND OF COLD AIR WILL FOLLOW
BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH FRIDAY...WITH THE
POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT OFF OF LAKE
ONTARIO. WHILE THE NEXT ROUND OF COLD DOESNT APPEAR AS POTENT AS THE
CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP TEMPERATURES WELL
BELOW NORMAL.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
WARM ADVECTION AND MOISTURE WILL INCREASE THIS MORNING AHEAD OF AN
APPROACHING ARCTIC FRONT...AND CONSEQUENTLY LIGHT SNOW SHOWERS WILL
ALSO DEVELOP FROM WEST TO EAST. EXPECT VARIABLE CONDITIONS THROUGH
15Z IN AND OUT OF STEADIER SNOW SHOWERS.
LATER THIS MORNING AND INTO THIS AFTERNOON LOW LEVEL CONVERGENCE AND
LIFT WILL DRAMATICALLY INCREASE WITH THE APPROACH AND PASSAGE OF THE
ARCTIC COLD FRONT...AND WILL ALSO COINCIDE WITH A PERIOD OF
IMPRESSIVE INSTABILITY. THIS WILL LIKELY LEAD TO A BRIEF BURST OF
INTENSE SNOW THAT WILL SWEEP ACROSS THE REGION...WHICH WILL BE
FURTHER COMPLICATED BY INCREASING WINDS WHICH SHOULD PRODUCE
CONSIDERABLE BLOWING AND DRIFTING SNOW. ALL OF THIS SHOULD LEAD TO A
SHORT PERIOD OF VLIFR/LIFR CONDITIONS ACCOMPANYING THE FRONTAL
PASSAGE...WITH CONDITIONS THEN IMPROVING BACK TO IFR/MVFR IN ITS
WAKE.
TONIGHT...EXPECT FAIRLY WIDESPREAD SNOW/SNOW SHOWERS TO PERSIST...
ALONG WITH IFR/LOW-END MVFR CONDITIONS.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...CHURCH
LONG TERM...CHURCH
AVIATION...APFFEL/JJR
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
350 AM EST SAT FEB 14 2015
.SYNOPSIS...ARCTIC HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST
WILL MOVE OFFSHORE TODAY...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MON.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 945 PM FRIDAY...
TONIGHT...HIGH CLOUDS HAVE MOVED OFF TO THE EAST AND SKIES HAVE
CLEARED OUT ACROSS THE CWA...AT THE SAME TIME WINDS HAVE
CALMED...SETTING UP OPTIMAL CONDITIONS FOR RADIATIONAL COOLING.
TEMPERATURES ARE CURRENTLY HOLDING IN THE MID TO UPPER 20S. DUAL
SHORTWAVES TO THE WEST...ONE PASSING NORTH OF THE AREA...AND THE
OTHER DIVING SOUTHWEST OF CENTRAL NC HAVE LEFT A VOID IN UPSTREAM
MOISTURE. ALTHOUGH FORECAST SOUNDINGS LOOK FAIRLY GOOD FOR
OROGRAPHIC CIRRUS ENHANCEMENT...THE UPPER LEVEL MOISTURE IS REALLY
LACKING AND IT WILL BE HARD TO GENERATE ANYTHING THE REST OF THE
NIGHT AND THIS MORNING ALTHOUGH THERE IS ONE AREA OF SLIGHTLY
ENHANCED MOISTURE MOVING ACROSS EASTERN KY THAT BEARS WATCHING AS IT
APPROACHES THE APPALACHIANS. AFTER MIDNIGHT...THERE IS SOME
EXPECTATION THAT WINDS WILL INCREASE A LITTLE BIT WITH A VERY
SHALLOW MIXED LAYER. RAP SOUNDINGS SHOW THIS SHOULD BE MOST
PREDOMINANT IN THE TRIAD WITH WINDS UP TO 8 KTS OR SO POSSIBLE AT
TIMES. THE UPSHOT OF THIS COULD BE A FAIRLY SPOTTY MINIMUM
TEMPERATURE MAP AS SOME AREAS MAINTAIN OPTIMAL RADIATIONAL
COOLING...AND OTHERS DO NOT. IN GENERAL EXPECT UPPER TEENS TO LOW
20S FOR LOWS BUT DO NOT BE SURPRISED TO SEE A COUPLE OF LOW TO MID
TEENS READINGS THROUGH IN THERE. -ELLIS
SATURDAY...A LEE SIDE TROUGH WILL SHARPEN IN THE AFTERNOON AS
ANOTHER ARCTIC COLD FRONT APPROACHES FROM THE NW AND THE SFC HIGH
SETS UP OVER THE NORTHERN GULF. THIS SET-UP WILL RESULT IN A
STRENGTHENING SW LOW LEVEL FLOW. IN THESE EVENTS...USUALLY SEE A
LARGER THAN NORMAL DIURNAL TEMP RECOVERY. AFTER MIN TEMPS IN THE
TEENS/LOWER 20S...POTENTIAL FOR TEMPS TO RISE A SOLID 30
DEGREES...POSSIBLY 35. HAVE GONE CONSERVATIVE WITH MAX TEMPS NEAR 50-
LOWER 50S BUT WOULD NOT BE SURPRISED TO SEE SOME MID-UPPER 50S INT EH
FAR SOUTH-SE AND MID 50S AS FAR NORTH AS RDU. EXPECT A STOUT SW WIND
15-20MPH IN THE AFTERNOON WITH GUSTS 28-33 MPH. THESE WIND
PARAMETERS ALONG WITH A DRY AIR MASS WILL RESULT IN CRITICAL FIRE
WEATHER CONDITIONS (SEE FIRE WEATHER SECTION BELOW).
MAY SEE AN INCREASE IN CLOUD COVERAGE LATE IN THE DAY AS THE ARCTIC
BOUNDARY GETS CLOSER. -WSS
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 325 PM FRIDAY...
ARCTIC FRONT...BEING PUSHED
ALONG BY A STRONG S/W CROSSING THE EASTERN LAKES INTO THE NORTHERN
MID ATLANTIC...WILL PLOW SEWD ACROSS CENTRAL NC SATURDAY EVENING.
SIMILAR TO THURSDAY`S EVENT...MAY SEE A FEW RAIN SHOWERS OR
SPRINKLES/FLURRIES ACROSS THE NE PIEDMONT AND NORTHERN COASTAL PLAIN
SATURDAY EVENING BEHIND THE FRONT. FRONTAL PASSAGE WILL BE NOTED BY
SFC WINDS VEERING TO THE NW AND GUSTING AS HIGH AS 40-45 MPH 2-4
HOURS AFTER FROPA THEN "SUBSIDE" 25-35 MPH GUSTS OVERNIGHT. THIS
FLOW WILL ADVECT A VERY COLD DRY AIR MASS INTO CENTRAL NC. APPEARS
TO BE ENOUGH MIXING TO HELP TO KEEP TEMPS UP A BIT FROM EARLIER
THINKING. MIN TEMPS 15 NW TO NEAR 20 SE. RESULTANT WIND CHILLS IN
THE SINGLE DIGITS APPEAR LIKELY...POSSIBLY CLOSE TO WIND CHILL
ADVISORY CRITERIA IN THE NORTHERN PIEDMONT.
BLUSTERY NW WINDS WILL PERSIST INTO SUNDAY MORNING-EARLY AFTERNOON
UNDER SUNNY-MOSTLY SUNNY SKIES. WITH 850MB THERMAL TROUGH OVER THE
REGION...STRONG PROBABILITY THAT MUCH OF THE REGION WILL REMAIN
BELOW FREEZING. NEXT SYSTEM EXPECTED TO APPROACH FROM THE WEST-NW
LATE SUNDAY NIGHT. BASED ON TIMING...THIS MAY INCREASE HIGH LEVEL
CLOUDS ACROSS THE REGION AFTER MIDNIGHT. STILL...WITH AN ARCTIC AIR
MASS IN PLACE AND WINDS LIKELY BECOME CALM AT SUNSET...SHOULD SEE
TEMPS FALL INTO THE 12-17 DEGREE RANGE WITH A FEW 5-10 ABOVE
POSSIBLE IN THE NORMALLY COLDER LOCATIONS OF THE NE PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
...WINTER WEATHER POSSIBLE EARLY NEXT WEEK..
CONFIDENCE REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND
TUESDAY OF NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY
CONVERGENCE TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 130 AM SATURDAY...
CALM TO OCCASIONALLY LIGHT SOUTHERLY WINDS THIS MORNING WILL BECOME
SW TO SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW
BETWEEN MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 330 PM FRIDAY
A STOUT SW SFC WIND WITH SUSTAINED SPEEDS 15-20 MPH
AND GUSTS AROUND 30 MPH ALONG WITH LOW RH VALUES SIGNAL THE
POTENTIAL FOR RED FLAG CONDITIONS...MAINLY ACROSS THE SOUTH HALF OF
CENTRAL NC SATURDAY AFTERNOON. IN COORDINATION WITH THE NC FORESTRY
SERVICE...A FIRE WEATHER WATCH HAS BEEN FOR SATURDAY AFTERNOON FOR
AREAS GENERALLY SOUTH OF A GOLDSBORO-SANFORD-ALBEMARLE LINE. IF
CONDITIONS EARLY SATURDAY APPEAR SIMILAR...THE WATCH WILL BE
UPGRADED TO A RED FLAG WARNING MEANING ANY FIRES THAT OCCUR MAY
QUICKLY BURN OUT OF CONTROL.
OVER THE REMAINDER OF CENTRAL NC...AN INCREASE FIRE DANGER STATEMENT
WILL BE IN EFFECT AS PARAMETERS WILL BE JUST SHY OF RED FLAG
CRITERIA.
ESSENTIALLY...ANY OUTDOOR BURNING SHOULD BE DELAYED UNTIL LESS
VOLATILE CONDITIONS OCCUR.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH SATURDAY AFTERNOON FOR NCZ042-73>078-083>086-088-
089.
&&
$$
SYNOPSIS...RAH
NEAR TERM...ELLIS/WSS
SHORT TERM...WSS
LONG TERM...BLS
AVIATION...RAH
FIRE WEATHER...WSS
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
135 AM EST SAT FEB 14 2015
.SYNOPSIS...ARCTIC HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST
WILL MOVE OFFSHORE TODAY...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MON.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 945 PM FRIDAY...
TONIGHT...HIGH CLOUDS HAVE MOVED OFF TO THE EAST AND SKIES HAVE
CLEARED OUT ACROSS THE CWA...AT THE SAME TIME WINDS HAVE
CALMED...SETTING UP OPTIMAL CONDITIONS FOR RADIATIONAL COOLING.
TEMPERATURES ARE CURRENTLY HOLDING IN THE MID TO UPPER 20S. DUAL
SHORTWAVES TO THE WEST...ONE PASSING NORTH OF THE AREA...AND THE
OTHER DIVING SOUTHWEST OF CENTRAL NC HAVE LEFT A VOID IN UPSTREAM
MOISTURE. ALTHOUGH FORECAST SOUNDINGS LOOK FAIRLY GOOD FOR
OROGRAPHIC CIRRUS ENHANCEMENT...THE UPPER LEVEL MOISTURE IS REALLY
LACKING AND IT WILL BE HARD TO GENERATE ANYTHING THE REST OF THE
NIGHT AND THIS MORNING ALTHOUGH THERE IS ONE AREA OF SLIGHTLY
ENHANCED MOISTURE MOVING ACROSS EASTERN KY THAT BEARS WATCHING AS IT
APPROACHES THE APPALACHIANS. AFTER MIDNIGHT...THERE IS SOME
EXPECTATION THAT WINDS WILL INCREASE A LITTLE BIT WITH A VERY
SHALLOW MIXED LAYER. RAP SOUNDINGS SHOW THIS SHOULD BE MOST
PREDOMINANT IN THE TRIAD WITH WINDS UP TO 8 KTS OR SO POSSIBLE AT
TIMES. THE UPSHOT OF THIS COULD BE A FAIRLY SPOTTY MINIMUM
TEMPERATURE MAP AS SOME AREAS MAINTAIN OPTIMAL RADIATIONAL
COOLING...AND OTHERS DO NOT. IN GENERAL EXPECT UPPER TEENS TO LOW
20S FOR LOWS BUT DO NOT BE SURPRISED TO SEE A COUPLE OF LOW TO MID
TEENS READINGS THROUGH IN THERE. -ELLIS
SATURDAY...A LEE SIDE TROUGH WILL SHARPEN IN THE AFTERNOON AS
ANOTHER ARCTIC COLD FRONT APPROACHES FROM THE NW AND THE SFC HIGH
SETS UP OVER THE NORTHERN GULF. THIS SET-UP WILL RESULT IN A
STRENGTHENING SW LOW LEVEL FLOW. IN THESE EVENTS...USUALLY SEE A
LARGER THAN NORMAL DIURNAL TEMP RECOVERY. AFTER MIN TEMPS IN THE
TEENS/LOWER 20S...POTENTIAL FOR TEMPS TO RISE A SOLID 30
DEGREES...POSSIBLY 35. HAVE GONE CONSERVATIVE WITH MAX TEMPS NEAR 50-
LOWER 50S BUT WOULD NOT BE SURPRISED TO SEE SOME MID-UPPER 50S INT EH
FAR SOUTH-SE AND MID 50S AS FAR NORTH AS RDU. EXPECT A STOUT SW WIND
15-20MPH IN THE AFTERNOON WITH GUSTS 28-33 MPH. THESE WIND
PARAMETERS ALONG WITH A DRY AIR MASS WILL RESULT IN CRITICAL FIRE
WEATHER CONDITIONS (SEE FIRE WEATHER SECTION BELOW).
MAY SEE AN INCREASE IN CLOUD COVERAGE LATE IN THE DAY AS THE ARCTIC
BOUNDARY GETS CLOSER. -WSS
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 325 PM FRIDAY...
ARCTIC FRONT...BEING PUSHED
ALONG BY A STRONG S/W CROSSING THE EASTERN LAKES INTO THE NORTHERN
MID ATLANTIC...WILL PLOW SEWD ACROSS CENTRAL NC SATURDAY EVENING.
SIMILAR TO THURSDAY`S EVENT...MAY SEE A FEW RAIN SHOWERS OR
SPRINKLES/FLURRIES ACROSS THE NE PIEDMONT AND NORTHERN COASTAL PLAIN
SATURDAY EVENING BEHIND THE FRONT. FRONTAL PASSAGE WILL BE NOTED BY
SFC WINDS VEERING TO THE NW AND GUSTING AS HIGH AS 40-45 MPH 2-4
HOURS AFTER FROPA THEN "SUBSIDE" 25-35 MPH GUSTS OVERNIGHT. THIS
FLOW WILL ADVECT A VERY COLD DRY AIR MASS INTO CENTRAL NC. APPEARS
TO BE ENOUGH MIXING TO HELP TO KEEP TEMPS UP A BIT FROM EARLIER
THINKING. MIN TEMPS 15 NW TO NEAR 20 SE. RESULTANT WIND CHILLS IN
THE SINGLE DIGITS APPEAR LIKELY...POSSIBLY CLOSE TO WIND CHILL
ADVISORY CRITERIA IN THE NORTHERN PIEDMONT.
BLUSTERY NW WINDS WILL PERSIST INTO SUNDAY MORNING-EARLY AFTERNOON
UNDER SUNNY-MOSTLY SUNNY SKIES. WITH 850MB THERMAL TROUGH OVER THE
REGION...STRONG PROBABILITY THAT MUCH OF THE REGION WILL REMAIN
BELOW FREEZING. NEXT SYSTEM EXPECTED TO APPROACH FROM THE WEST-NW
LATE SUNDAY NIGHT. BASED ON TIMING...THIS MAY INCREASE HIGH LEVEL
CLOUDS ACROSS THE REGION AFTER MIDNIGHT. STILL...WITH AN ARCTIC AIR
MASS IN PLACE AND WINDS LIKELY BECOME CALM AT SUNSET...SHOULD SEE
TEMPS FALL INTO THE 12-17 DEGREE RANGE WITH A FEW 5-10 ABOVE
POSSIBLE IN THE NORMALLY COLDER LOCATIONS OF THE NE PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 335 PM FRIDAY...
...WINTER WEATHER POSSIBLE EARLY TO MID NEXT WEEK...
MONDAY THROUGH TUESDAY NIGHT: UNSETTLE WEATHER IS EXPECTED NEXT WEEK
IN THE EARLY TO MIDWEEK TIME FRAME... AS A SERIES OF S/W
DISTURBANCES ARE EXPECTED TO CROSS THE REGION. THE FIRST LEAD
IMPULSE IS EXPECTED TO MOVE ACROSS THE AREA ON MONDAY.... AS S/W
ENERGY ACROSS THE CENTRAL PLAINS ON SUNDAY NIGHT SHIFTS QUICKLY EAST
AND ACROSS THE MID ATLANTIC REGION BY MONDAY NIGHT. THE LATEST ECMWF
AND NAM GENERATE SOME PRECIP OVER THE AREA ON MONDAY AS THIS SYSTEM
TRACK ACROSS THE REGION. HOWEVER... THE GFS CONTINUES TO TREND DRY.
GIVEN THE DRY AND COLD LOW LEVEL ANTECEDENT AIRMASS... THINK IF WE
DO INDEED GET SOME PRECIP IT SHOULD BE ON THE LIGHT SIDE. HOWEVER...
WITH HIGHS STRUGGLING TO REACH FREEZING ON MONDAY ANY PRECIP THAT
FALLS WILL LIKELY BE IN THE FORM OF SNOW. IN FACT THE LATEST ECMWF
STATISTICAL GUIDANCE GENERALLY KEEPS TEMPS BELOW FREEZING ALL DAY ON
MONDAY... WITH TEMPS STRUGGLING TO REACH 25 IN THE TRIAD. THUS...
*IF* PRECIP DOES DEVELOP WE COULD SEE PROBLEMS DEVELOP WITH EVEN
LIGHT AMOUNTS OF SNOWFALL MONDAY (BEST CHANCE ACROSS THE
WEST/NORTHWEST PIEDMONT). FOR NOW WILL JUST ADD A SLIGHT CHANCE OF
SNOW ACROSS MOST OF THE AREA ON MONDAY... AND LOWER HIGH TEMPS INTO
THE LOWER TO MID 30S.
THE BEST CHANCE FOR PRECIP IS EXPECTED ON MONDAY NIGHT INTO TUESDAY
NIGHT... AS A MUCH DEEPER/STRONGER TROUGH AMPLIFIES ACROSS THE DEEP
SOUTH HELPING TO SPAWN A SURFACE LOW NEAR THE NORTHER GULF COAST...
WITH THE LOW TRANSLATING NORTH AND EASTWARD AND OFF THE ATLANTIC
COAST BY TUESDAY. MEDIUM RANGE MODEL GUIDANCE HAS HAD A HARD TIME
WITH HOW MUCH MOISTURE WILL SPREAD ACROSS CENTRA NC. IT STILL
APPEARS THAT WE SHOULD BE SUFFICIENTLY COLD TO SUPPORT ALL SNOW
INITIALLY FOR THE ENTIRE AREA... (GIVEN PRECIP DOES SPREAD INTO OUR
REGION). OVER THE PAST FEW DAYS GUIDANCE HAS TRENDED TOWARDS A LOW
TRACK OFFSHORE AND NOT OVER CENTRAL NC OR TO THE WEST OF THE
MOUNTAINS. THUS.. FOR NOW WILL STICK CLOSE TO WPC POP FORECAST AND
TREND ANY P-TYPE CORRIDORS TO NARROW TRANSITION ZONES... THANKS TO
THE SINGLE SURFACE LOW OFFSHORE WITH THIS SYSTEM. AS CLASSIC WITH
THESE CASES... AS THE SURFACE HIGH SHIFTS OFFSHORE WE SHOULD SEE THE
RAIN/SNOW LINE PIVOT BACK TO THE NORTHWEST BY TUESDAY AFTERNOON
(HOWEVER BACK TO THE NORTHWEST IS STILL VERY MUCH UNCERTAIN)... WITH
A POSSIBLE PUSH OF ALL SNOW ACROSS THE ENTRIE AREA AS THE LOW BEGINS
TO LIFT OFF TO THE NORTH AND EAST OF THE AREA ON TUESDAY NIGHT.
GIVEN TIMING AND TRACK DIFFERENCES IN THE GUIDANCE IT IS VERY HARD
TO GIVE ANY EXPECTED SNOWFALL AMOUNTS ACROSS CENTRAL NC AT THIS
TIME. HOWEVER... CONFIDENCES IN INCREASING FOR A POTENTIAL WINTER
STORM TO AFFECT PORTIONS IF NOT ALL OF OUR AREA EARLY/MID NEXT
WEEK...WITH SNOWFALL ACCUMULATION POSSIBLE ACROSS (AT LEAST) PARTS
OF THE FORECAST AREA.
WEDNESDAY THROUGH FRIDAY: THE DEEPENING LOW WILL LIFT OFF TO THE
NORTHEAST OF THE AREA ON WEDNESDAY... WITH THE MAIN S/W TROUGH AXIS
CROSSING OUR REGION. THIS SHOULD RESULT IN A RETURN TO DRIER
WEATHER. HOWEVER... WITH A DEEP L/W TROUGH REMAINING ACROSS THE
EASTERN HALF OF THE COUNTRY... AND CENTERED OVER THE EAST COAST...
WE CAN EXPECT WELL BELOW NORMAL TEMPS... WITH THE POSSIBILITY OF
CLIPPER SYSTEMS MOVING ACROSS THE AREA. BOTH THE LATEST GFS AND
ECMWF SHOW ONE SUCH SYSTEM TRACKING ACROSS THE AREA... WITH THE VORT
CENTER TRACKING JUST TO THE SOUTH OF THE AREA LATE WEEK... WHICH
COULD RESULT IN SOME SNOW SHOWERS SOME TIME LATE WEEK. HOWEVER...
WILL KEEP THE FORECAST DRY FOR NOW... AS SUCH SYSTEMS ARE VERY HARD
TO TRACK ONLY A COUPLE DAYS OUT IN THE FORECAST.... LET ALONG DAYS 6
AND 7 OF THE FORECAST. WILL KEEP TEMPS IN THE 30S FOR HIGHS AND LOWS
IN THE TEENS AND 20S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 130 AM SATURDAY...
CALM TO OCCASIONALLY LIGHT SOUTHERLY WINDS THIS MORNING WILL BECOME
SW TO SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW
BETWEEN MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 330 PM FRIDAY
A STOUT SW SFC WIND WITH SUSTAINED SPEEDS 15-20 MPH
AND GUSTS AROUND 30 MPH ALONG WITH LOW RH VALUES SIGNAL THE
POTENTIAL FOR RED FLAG CONDITIONS...MAINLY ACROSS THE SOUTH HALF OF
CENTRAL NC SATURDAY AFTERNOON. IN COORDINATION WITH THE NC FORESTRY
SERVICE...A FIRE WEATHER WATCH HAS BEEN FOR SATURDAY AFTERNOON FOR
AREAS GENERALLY SOUTH OF A GOLDSBORO-SANFORD-ALBEMARLE LINE. IF
CONDITIONS EARLY SATURDAY APPEAR SIMILAR...THE WATCH WILL BE
UPGRADED TO A RED FLAG WARNING MEANING ANY FIRES THAT OCCUR MAY
QUICKLY BURN OUT OF CONTROL.
OVER THE REMAINDER OF CENTRAL NC...AN INCREASE FIRE DANGER STATEMENT
WILL BE IN EFFECT AS PARAMETERS WILL BE JUST SHY OF RED FLAG
CRITERIA.
ESSENTIALLY...ANY OUTDOOR BURNING SHOULD BE DELAYED UNTIL LESS
VOLATILE CONDITIONS OCCUR.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH SATURDAY AFTERNOON FOR NCZ042-73>078-083>086-088-
089.
&&
$$
SYNOPSIS...RAH
NEAR TERM...ELLIS/WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...RAH
FIRE WEATHER...WSS
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS ALBANY NY
640 AM EST SAT FEB 14 2015
.SYNOPSIS...
A POWERFUL CLIPPER SYSTEM WILL IMPACT THE REGION TODAY WITH SNOW
ACROSS THE ENTIRE REGION. THIS STORM WILL RAPIDLY INTENSIFY OFF
THE NEW ENGLAND COAST TONIGHT. INCREASING WINDS AND DANGEROUS
WIND CHILLS ON THE BACK SIDE OF THIS INTENSE STORM WILL BE FELT
SUNDAY INTO SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
..WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW..
AS OF 630 AM EST...LIGHT SNOW WAS MAKING PROGRESS INTO EASTERN NY
WITH REPORTS OF VIRGA TO THE WEST OF ALBANY. LATEST 06Z GUIDANCE
AND HRRR CONTINUE TO SUGGEST THE SNOW TODAY WILL BE RATHER LIGHT.
MINOR UPDATES TO THE HOURLY GRIDS BASED ON OBSERVATIONS.
AS OF 300 AM EST...THIS MORNINGS H2O VAPOR LOOP DEPICTS A
POWERFUL SHORT WAVE CURRENTLY DIGGING/AMPLIFYING ACROSS THE STATE
OF WISCONSIN. AHEAD OF THIS FEATURE...A BROAD ISENTROPIC LIFT WARM
ADVECTION REGIME ALOFT COMBINING WITH UPPER LEVEL EXIT REGION
DYNAMICS WILL RESULT IN LIGHT SNOW OVERSPREAD THE ENTIRE CWFA
THIS MORNING. INITIALLY...DUE TO THE DRY COLUMN...THE INITIAL
BURST OF SNOW WILL LIKELY BE VIRGA. HOWEVER...THE COLUMN WILL
EVENTUALLY SATURATE FOR SNOW TO BEGIN LATER THIS MORNING FROM WEST
TO EAST. ISENTROPIC ANALYSIS ON THE 280K SURFACE REVEALS THE
CONTINUOUS LIFT ON THE SURFACE WITH SPECIFIC HUMIDITIES ON THE
SURFACE AVERAGING AROUND 1 G/KG. THIS WOULD SUGGEST THE SNOW WILL
GENERALLY BE LIGHT THROUGH THE DAY WITH THE UPSLOPE FAVORED
TERRAIN AREAS LIKELY SEEING A LITTLE ADDITIONAL BOOST. THE FLUFF
FACTOR FOR THE SNOW /SNOW RATIO/ WILL BE HIGHER THAN CLIMATOLOGY
WITH VALUES AROUND 15:1. THE FORECAST QPF FROM COORDINATION FROM
WPC YIELDS AROUND 0.10 SO GENERALLY 1-2 INCHES DURING THE DAYLIGHT
HOURS. AS FOR HIGH TEMPERATURES...TEENS TO LOWER 20S ARE EXPECTED.
TONIGHT...AS THE POTENT UPPER WAVE MOVES OFF THE MID-ATLANTIC/NEW
ENGLAND COAST THIS EVENING...EXPLOSIVE CYCLOGENESIS WILL
COMMENCE. THE CHALLENGE FOR OUR REGION IS IF/WHERE THE INVERTED
TROUGH AXIS DEVELOPS AND EVOLVING TROWAL/DEFORMATION. THE 00Z/06Z
NAM12 REMAINS CONSISTENT WITH THE INVERTED TROUGH AXIS SETTING UP
MAINLY TO THE SOUTH OF I90. 00Z GFS IS FURTHER NORTH WHICH WOULD
IMPACT THE I90 CORRIDOR AND THE 00Z ECMWF IS INBETWEEN. THE OTHER
COMPLICATED FACTOR TO THIS IS CROSS SECTIONS REVEAL A TROPOPAUSE
FOLD OCCURRING ACROSS EASTERN NY WHICH COULD CUT DOWN OUR SNOW
ACCUMULATIONS AS WELL. GIVEN THE UNCERTAINTY WHERE AND JUST HOW
INTENSE THIS INVERTED TROUGH AXIS WILL BE...WE WILL CONTINUE WITH
THE SNOW AND BLOWING SNOW ADVISORY THROUGH TONIGHT.
FURTHERMORE...BUFKIT PROFILES ACROSS THE REGION SUGGEST WITHIN
THIS BAND OF SNOW...THE MAX LIFT WILL OCCUR WITHIN THE FAVORED
DENDRITIC GROWTH ZONE WHERE SNOW RATES COULD BE MAXIMIZED. PER
COORDINATION WPC QPF VALUES...ANOTHER 1-4 INCHES ARE EXPECTED.
GIVEN THE TIME FRAME OF THIS SNOW EVENT...WE FELT WE WOULD NOT
EXCEED OUR 7 INCHES IN 12 HOURS NOR THE 9 INCHES IN 24 HOURS FOR
ANYTHING HIGHER THAN AN ADVISORY. THANKS FOR THE EXTENSIVE
COLLABORATION TO NEIGHBORING FORECAST OFFICES THIS MORNING.
WINDS WILL INCREASE OVERNIGHT AND WHERE SNOW HAS FALLEN ALONG WITH
PREVIOUS SNOW ON THE GROUND...CONSIDERABLE BLOWING SNOW IS
EXPECTED. POTENTIAL MIXING LAYER HEIGHTS SUGGEST WIND GUSTS WILL
BE WITHIN THE 20KT RANGE /FUNNELING DOWN THE HUDSON COULD INCREASE
THOSE MAGNITUDES FURTHER CLOSER TO 30 KTS/.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
..WIND CHILL WARNINGS POSTED FOR THE ENTIRE REGION..
AS THE METEOROLOGICAL BOMB DEEPENS FURTHER IN THE GULF OF
MAINE...DEFORMATION AXIS IS FORECAST TO LINE UP ALONG OR JUST EAST
OF THE HUDSON RIVER SUNDAY MORNING. WE WILL HOLD ONTO THE ADVISORY
THROUGH THE MID MORNING HOURS WITH THE BEST POTENTIAL FOR
ADDITIONAL ACCUMULATING SNOW ALONG AND EAST OF I87. THE MAIN
HAZARD WILL BE THE INCREASE WINDS AND FALLING TEMPERATURES. MIXING
LAYER HEIGHTS SUGGEST WE TAP INTO THE 30KT RANGE ALONG WITH
FUNNELING INTO THE VALLEY LOCATIONS WILL RESULT IN ADDITIONAL
BLOWING SNOW. BUT THE FALLING TEMPERATURES COMBINING WITH THESE
WINDS WILL RESULT IN BITTERLY COLD...DANGEROUS...LIFE THREATING
WIND CHILLS! AFTER EXTENSIVE COORDINATION...WIND CHILL WARNINGS
WILL BE ISSUED FOR THE ENTIRE CWFA. TEMPERATURES SUNDAY NIGHT WILL
FALL WELL BELOW ZERO WITH WIND CHILLS APPROACHING 50 BELOW ZERO
INTO THE ADIRONDACK REGION WITH 25 TO 40 BELOW ZERO ELSEWHERE.
SKIES WILL LIKELY QUICKLY CLEAR SUNDAY EVENING AS WELL FURTHER
INCREASING THE POTENTIAL FOR THESE LOW TEMPERATURES.
SUBSIDENCE INCREASES QUICKLY OVERNIGHT INTO MONDAY MORNING AS
SURFACE HIGH OVER THE OHIO VALLEY AND LOWER GREAT LAKES BUILDS
INTO THE REGION. A GREAT DEAL OF SUNSHINE IS FORECAST MONDAY ALONG
WITH DIMINISHING WINDS AS THE WIND CHILL WARNING HEADLINE IS SET
TO EXPIRE AROUND NOON /MAY TRANSITION TO AN ADVISORY BUT WE WILL
MONITOR TRENDS AND ADJUST ACCORDINGLY/.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
TO START THE EXTENDED PERIOD...ANOTHER VERY COLD NIGHT IS EXPECTED
FOR MONDAY NIGHT. LUCKILY...WINDS WILL BECOMING LIGHT DURING THE
OVERNIGHT HOURS THANKS TO HIGH PRESSURE MOVING OVER THE AREA...SO
WIND CHILL WON/T BE A BIG FACTOR. STILL...OVERNIGHT LOWS ARE
EXPECTED TO BE BRUTAL OVER THE REGION...WITH MIN TEMPS BELOW ZERO
EVERYWHERE...WITH -10 TO -20 OVER THE HIGH TERRAIN.
THE HIGH PRESSURE AREA WILL SLIDE EASTWARD FOR TUESDAY MORNING
...BUT WILL REMAIN CLOSE ENOUGH TO THE AREA TO ALLOW FOR CONTINUED
DRY WEATHER THROUGH THE MORNING. TEMPS WILL CONTINUE TO BE BELOW
NORMAL...WITH HIGHS ONLY IN THE MID TEENS TO MID 20S. CLOUDS WILL
START TO INCREASE FOR TUESDAY AFTERNOON AND SOME LIGHT SNOWFALL MAY
BEGIN IN FAR SOUTHWESTERN AREAS BY THE LATE AFTN OR EARLY EVENING
HOURS. THIS WILL ULTIMATELY DEPEND ON THE TRACK OF A SOUTHERN STREAM
SFC LOW PRESSURE AREA MOVING UP THE EASTERN SEABOARD. WHILE SOME
RECENT MODEL GUIDANCE...INCLUDING THE 00Z ECMWF...SHOW THIS SYSTEM
REMAINING FAR ENOUGH SOUTH AND EAST TO HAVE LITTLE IMPACT ON THE
AREA...THERE STILL REMAINS SOME UNCERTAINTY. THE 00Z GFS AND MANY OF
THE 00Z GEFS MEMBERS CONTINUE TO SHOW AN IMPACT OF AT LEAST LIGHT TO
MODERATE SNOW BY LATE TUESDAY INTO TUESDAY NIGHT...AND ENDING
WEDNESDAY MORNING. WITH THIS UNCERTAINTY IN MIND...WILL CONTINUE
TO GO WITH CHC POPS FOR SNOW DURING THIS TIME PERIOD. TEMPS WILL
CONTINUE TO BE VERY COLD...WITH SINGLE DIGITS FOR TUESDAY
NIGHT...AND MID TEENS TO MID 20S ON WEDNESDAY.
BEHIND THIS STORM SYSTEM...ANOTHER BLAST OF FRIGID ARCTIC AIR LOOKS
TO MOVE TOWARDS THE REGION FOR THE LAKE WEEK PERIOD. SOME LAKE
EFFECT SNOW MAY IMPACT FAR NORTHWESTERN AREAS AS WELL...WITH SOME
FLURRIES POSSIBLE ELSEWHERE THANKS TO A DEEP AND COLD UPPER LEVEL
TROUGH OVER THE REGION. TEMPS ON WED/THURS NIGHTS WILL BE BELOW
ZERO FOR MOST LOCATIONS...WITH TEMPS CLOSING IN ON -20 ACROSS THE
ADIRONDACKS. HIGHS ON THURS/FRI ONLY LOOK TO REACH THE SINGLE
DIGITS TO LOW TEENS.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... DURING THE MORNING
TODAY...BKN-OVC CIGS WILL CONTINUE TO LOWER AND THICKEN. WINDS WILL
BE LIGHT FROM A SOUTHERLY DIRECTION. MUCH OF THE MORNING WILL BE
DRY...ALTHOUGH A FEW VERY LIGHT FLURRIES OR AREAS OF LIGHT SNOW MAY
START TO MOVE TOWARDS THE TAF SITES TOWARDS THE LATE MORNING HOURS.
BASED ON THE LATEST HIRES NAM/HRRR GUIDANCE...LIGHT SNOWFALL LOOKS
TO EXPAND FROM WEST TO EAST ACROSS THE REGION DURING THE AFTERNOON
HOURS. ALTHOUGH SNOWFALL WILL BE LIGHT...EXPECT THIS STEADY SNOW TO
BEGIN AND DROP VSBYS TO IFR BY ABOUT 18-19Z FOR ALL TAF SITES. LIGHT
SNOW WILL CONTINUE THROUGH THE REMAINDER OF THE DAY...AND MAY BECOME
SOMEWHAT HEAVIER TOWARDS EVENING...SO WILL CONTINUE TO ALLOW FOR
LOWER VSBYS/CIGS TOWARDS EVENING AND INTO THE OVERNIGHT HOURS.
SOUTH WINDS WILL BE IN PLACE AT 5-10 KTS DURING THE DAY TODAY. WINDS
WILL ABRUPTLY SWITCH TO A N-NW DIRECTION LATE THIS EVENING...AS AN
ARCTIC COLD FRONT PASSES THROUGH THE REGION. WINDS WILL START TO
BECOME STRONGER AND GUSTIER BY LATE TONIGHT...WITH A FEW GUSTS TO
NEAR 25 KTS AT KALB LATE TONIGHT. SNOWFALL WILL CONTINUE THROUGH
MUCH OF SAT NIGHT...ESP AT KPSF...BUT WILL START TO LIGHTEN UP BY
LATE IN THE NIGHT...ALTHOUGH BLOWING SNOW IS EXPECTED FOR ALL SITES.
FLYING CONDITIONS MAY RETURN TO MVFR FOR MOST SITES BY THE LATE
NIGHT HOURS...ALTHOUGH THIS IS RATHER LOW CONFIDENCE FOR WHEN
EXACTLY THIS WILL OCCUR.
OUTLOOK...
SUN: MODERATE OPERATIONAL IMPACT. CHC SHSN...BLSN.
SUN NIGHT-MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WEATHER.
TUE-WED: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
MUCH BELOW NORMAL TEMPERATURES WILL BE THE GENERAL RULE WHICH
WILL ALLOW ICE TO CONTINUE TO THICKEN ON RIVERS...STREAMS
CREEKS...LAKES AND OTHER BODIES OF WATER. SOME GAGES WILL
EXPERIENCE MORE ICE AFFECTS THROUGH THE WEEKEND.
A ROUND OF LIGHT TO MODERATE SNOWFALL TODAY INTO TONIGHT.
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.
&&
.CLIMATE...
GIVEN THE BITTERLY COLD TEMPERATURES ALOFT...WE LOOKED AT
CLIMATOLOGY FOR THE 850MB LEVEL. THE COLDEST EVER OBSERVED ON OUR
UPPER AIR SOUNDINGS WAS -30C. PER NCEP MODEL SUITE...THE LOWEST
VALUES AT UPPER AIR RELEASE TIMES /00Z/12Z/ ARE FORECAST TO BE
INTO THE NEGATIVE MID 20S C ON 00Z MON.
SURFACE TEMPERATURES...
RECORD LOW TEMPERATURES FOR MONDAY FEBRUARY 16TH:
LOCATIONTEMPYEAR
ALBANY-20F1943
GLENS FALLS-24F2004
POUGHKEEPSIE-3 F1963
BENNINGTON -13F2004
PITTSFIELD-26F1943
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR CTZ001-013.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
CTZ001-013.
NY...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR NYZ032-033-038>043-047>054-058>061-063>066-
082>084.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
NYZ032-033-038>043-047>054-058>061-063>066-082>084.
MA...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR MAZ001-025.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
MAZ001-025.
VT...WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
SUNDAY FOR VTZ013>015.
WIND CHILL WARNING FROM 10 AM SUNDAY TO NOON EST MONDAY FOR
VTZ013>015.
&&
$$
SYNOPSIS...GJM/BGM
NEAR TERM...BGM
SHORT TERM...GJM/BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...BGM
CLIMATE...BGM
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
752 AM CST SAT FEB 14 2015
.SHORT TERM...
332 AM CST
THROUGH SUNDAY...
NO CHANGES TO GOING HEADLINES FOR TODAY. HOWEVER...WE HAVE ISSUED A
WIND CHILL ADVISORY FOR THE AREA FOR TONIGHT.
MAIN WEATHER FORECAST CONCERNS CONTINUE TO FOCUS ON THE STRONG
ARCTIC PUSH TODAY...WITH DANGEROUS WIND CHILLS TONIGHT...AND ALSO
THE LAKE EFFECT SNOW SHOWERS...PARTICULARLY ACROSS NORTHWESTERN
INDIANA LATER TODAY AND TONIGHT...THEN OVER NORTHEASTERN ILLINOIS ON
SUNDAY.
WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS THE MAIN UPPER LEVEL PV
ANOMALY RAPIDLY DIGGING SOUTHWARD OVER NORTHERN WISCONSIN.
MEANWHILE...THE ASSOCIATED SURFACE LOW CONTINUES TO DEEPEN TO NEAR
1000 MB OVER THE UPPER GREAT LAKES REGION...WITH THE MAIN SURFACE
COLD FRONT RIGHT ON OUR DOOR STEP ACROSS FAR NORTHERN ILLINOIS.
TEMPERATURES AHEAD OF THIS FRONT AT STILL QUITE MILD IN THE UPPER
20S TO NEAR 30. HOWEVER...THE BOTTOM WILL FALL OUT IN A HURRY HERE
OVER THE NEXT FEW HOURS...AS TEMPERATURES QUICKLY TUMBLE INTO THE
TEENS AFTER DAYBREAK TODAY...AND CONTINUE TO FALL INTO THE SINGLE
DIGITS THIS AFTERNOON.
LOWER LEVEL LAPS RATES WILL STEEP UP FOLLOWING THE FRONTAL
PASSAGE...AND THIS SHOULD ALLOW FOR THE DEVELOPMENT OF SOME ISOLATED
TO SCATTERED SNOW SHOWERS ACROSS THE REGION THIS MORNING.
HOWEVER...IT APPEARS THE BETTER FOCUS FOR SNOW SHOWERS...OUTSIDE OF
LAKE EFFECT...WILL OCCUR ACROSS MY SOUTHERN AREAS THIS MORNING AS THE
LOWER LEVEL BAROCLINIC ZONE CONTINUES TO STRENGTHEN...SETTING UP A
BAND OF STRONG FGEN ACROSS CENTRAL ILLINOIS THIS MORNING. THIS WILL
BE A SHORT LIVED FEATURE...HOWEVER...SO SNOW AMOUNTS AREA-WIDE WILL
LIKELY REMAIN A HALF IN OR LESS.
NORTHERLY WINDS WILL INCREASE QUICKLY THIS MORNING...AND THE
COMBINATION OF VERY STRONG COLD AIR ADVECTION...AND RAPID PRESSURE
RISES...COULD RESULT IN A PERIOD OF NEAR WIND ADVISORY CRITERIA WINDS
(GUSTS TO 45 MPH)...PARTICULARLY ACROSS EASTERN ILLINOIS AND
NORTHWESTERN INDIANA LATER THIS MORNING AND INTO THE AFTERNOON.
MODEL SOUNDINGS ACROSS THESE AREAS INDICATE MEAN MIXING LAYER WINDS
AROUND 36 KT...WITH AROUND 40 TO 42 KT AT THE TOP OF MIXING LAYER.
STRONGLY FORCED COLD AIR ADVECTION REGIMES SUCH AS WHAT IS EXPECTED
THIS MORNING...CAN SET UP SITUATIONS WHEN SOME OF THE HIGHEST WINDS
IN THE MIXING LAYER MIX DOWN TO THE SURFACE AS WIND GUSTS...AT LEAST
FOR SHORT PERIODS OF TIME. IF THIS DOES OCCUR...THERE COULD BE A
SHORT PERIOD WITH WIND GUSTS TOPPING 45 MPH TODAY. OVERALL IT
APPEARS THE STRONGEST WIND POTENTIAL WILL BE NEAR THE LAKE IN
NORTHWESTERN INDIANA...AND THIS AREA IS CURRENTLY COVERED BY EITHER
A WIND ADVISORY OR A WINTER STORM WARNING. WE THOUGHT ABOUT POSSIBLY
EXPANDING THE WIND ADVISORY TO INCLUDE ALL OF NORTHWESTERN INDIANA
AND SOME OF EASTERN ILLINOIS. HOWEVER...AFTER COLLABORATING WITH
NEIGHBORING OFFICES...WE HAVE DECIDED NOT TO EXPAND THE CURRENT WIND
ADVISORY.
THE LAKE EFFECT POTENTIAL IS REALLY UNCHANGED FROM PREVIOUS
FORECASTS. IT STILL APPEARS THAT THE MAIN SETUP TODAY WILL FAVOR
NORTHEASTERN PORTER COUNTY INDIANA AND POINTS EAST...AS STRONG
NORTHWESTERN BOUNDARY LAYER WINDS KEEP THE BETTER LOWER LEVEL
CONVERGENCE MORE BROAD...AND MAINLY TO THE EAST OF MY AREA. THIS
COULD SUPPORT MULTIPLE BANDS OF LAKE EFFECT SNOW SHOWERS. HOWEVER...IT
STILL DOES APPEAR THAT AS A STOUT SURFACE BUILDS EASTWARD ACROSS THE
UPPER MIDWEST BY THIS EVENING...THAT THE BOUNDARY LAYER WINDS OVER
LAKE MICHIGAN WILL BECOME MORE NORTHERLY...AND GRADUALLY EASE IN
MAGNITUDE OVERNIGHT TONIGHT. THIS COULD SET UP MORE OF A SINGLE
CONVERGENT WESTWARD MOVING BAND OF LAKE EFFECT SNOW SHOWERS OVER
SOUTHERN LAKE MICHIGAN TONIGHT...AND BETTER ACCUMULATION POTENTIAL
FOR MY NORTHWESTERN INDIANA COUNTIES NEAR THE LAKE. INVERSION
HEIGHTS SHOULD BE ON A DECLINE DURING THIS TIME. HOWEVER...GIVEN THE
COLD AIRMASS...THE CLOUDS SHOULD BE COLD ENOUGH TO SUPPORT ICE
CRYSTALS. TOTAL SNOWFALL AMOUNTS SHOULD NOT GET TO OUT OF HAND...AS
THE BAND SHOULD BECOME PROGRESSIVE. HOWEVER...AMOUNTS IN EXCESS OF 6
INCHES ARE STILL POSSIBLE ACROSS PORTIONS OF THE WARNING AREA.
ADDITIONALLY...WITH THE STRONG WINDS TODAY AND THIS EVENING...BLOWING
SNOW AND WHITE OUT CONDITIONS WILL BE A CONCERN AT TIMES.
WINDS OVER THE LAKE WILL CONTINUE TO BACK MORE NORTHEASTERLY FOR A
PERIOD ON SUNDAY...SO SOME LIGHT LAKE EFFECT SNOW SHOWERS APPEAR
LIKELY ACROSS THE CHICAGO AREA OF NORTHEASTERN ILLINOIS.
HOWEVER...THE BAND OF SNOW SHOWERS LOOKS TO BECOME A LESS ORGANIZED
BY SUNDAY. THEREFORE...IT STILL APPEARS THAT ACCUMULATIONS ACROSS
THE CHICAGO AREA WILL GENERALLY REMAIN ON THE LIGHT SIDE. THE WINDS
ARE EXPECTED SHIFT OFFSHORE BY EARLY SUNDAY EVENING...SO ANY
LINGERING SHOWERS WILL END BY THIS TIME.
A WIND CHILL ADVISORY WILL GO INTO EFFECT FOR THE REGION THIS
EVENING. THE COMBINATION OF LINGERING BREEZY WINDS AND TEMPERATURES
FALLING INTO NEGATIVE TERRITORY THROUGH THE EVENING WILL SET UP WIND
CHILLS OF 20 BELOW TO 30 BELOW...WITH THE COLDEST EXPECTED ACROSS
NORTH CENTRAL ILLINOIS. THIS ADVISORY WILL BE IN EFFECT UNTIL MID
MORNING ON SUNDAY. TEMPERATURES LOOK TO ONLY TOP OUT NEAR 10 ABOVE IN
MOST AREAS ON SUNDAY...BUT WITH LIGHT WINDS DURING THE DAY...WIND
CHILLS SHOULD NOT BE AN ISSUE.
KJB
&&
.LONG TERM...
332 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
THE WEATHER PATTERN OVER THE COUNTRY WILL CONTINUE TO FAVOR
PERIODS OF COLD ARCTIC OUTBREAKS OVER THE EASTERN HALF OF THE
CONUS NEXT WEEK. STRONG HIGH LATITUDE UPPER RIDGING OVER THE EASTERN
PACIFIC/WESTERN NORTH AMERICA WILL SET THE STAGE FOR A FAIRLY
PROLONGED PERIOD OF MUCH BELOW NORMAL HEIGHTS AND TEMPERATURES
ACROSS MUCH OF EASTERN NORTH AMERICA. OUTSIDE OF LAKE EFFECT
SNOWS...NO BIG SNOW EVENTS ARE EXPECTED THROUGH THE PERIOD.
HOWEVER...SOME MINOR SNOW SYSTEMS COULD IMPACT THE AREA WITHIN THE
CYCLONIC UPPER LEVEL FLOW PATTERN. A REINFORCING SHOT OF COLD
ARCTIC AIR LOOKS TO SET UP OVER THE AREA BY MID WEEK...AND THIS
AIRMASS COULD EVEN BE A BIT COLDER THAN THE SHORT TERM COLD
EXPECTED. THIS COULD RESULT IN HIGH TEMPERATURES ONLY IN THE
SINGLE DIGITS IN MOST AREAS ON WEDNESDAY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHWEST TO NORTH-NORTHWEST WINDS GUSTING TO AROUND 35 KT
LATE MORNING THROUGH AFTERNOON.
* SCATTERED SNOW BANDS BRINGING INTERMITTENT PRIODS OF IFR VSBY.
POSSIBLE BRIEF PERIODS OF 1/2SM OR LESS...BUT TOO BRIEF TO CARRY
IN THE TEMPO GROUP.
* VARIABLE MVFR CIGS SCATTERING THIS AFTERNOON.
* SNOW CHANCES ONCE AGAIN SUNDAY WITH MVFR CIGS AND IFR VSBY
POSSIBLE.
KREIN
//DISCUSSION...UPDATED 12Z...
A COLD FRONTAL BOUNDARY IS CROSSING THE TERMINALS EARLY THIS
MORNING AND BRINGING A SHIFT TO NORTHWEST WINDS. STRONG HIGH
PRESSURE WILL MOVE IN FROM THE NORTH AS LOW PRESSURE MOVES FROM
SOUTHERN ONTARIO TO SOUTHERN NEW ENGLAND. THE INCREASING PRESSURE
GRADIENT BETWEEN THESE SYSTEMS AND AN INFLUX OF COLD AIR WILL
RESULT IN INTENSIFYING WINDS THROUGH THE MORNING. EXPECT THAT
GUSTS TO AROUND 30 KT WILL QUICKLY DEVELOP THIS MORNING WITH 35 KT
GUSTS POSSIBLE BY MIDDAY. GYY MAY SEE GUSTS AROUND 40 KT
CONSIDERING THEIR PROXIMITY TO THE LAKE. CIGS ARE MAINLY MVFR BUT
AM SEEING QUITE A BIT OF VARIABILITY IN BASE HEIGHT WITH SOME
AREAS OF VFR MIXED IN.
A PASSING UPPER TROUGH IS AIDING IN SNOW SHOWER DEVELOPMENT TO THE
NORTHWEST WHICH IS SPREADING INTO THE LOCAL TERMINALS. COVERAGE
WILL REMAIN LOW BUT THE MORE INTENSE SNOW SHOWERS WILL LIKELY
PRODUCE BRIEF PERIODS OF IFR VSBY AND LEAD TO SOME MINOR
ACCUMULATION. THE BULK OF THIS ACTIVITY WILL EXIT BY MIDDAY. LAKE
EFFECT SNOW WILL TAKE OVER INTO NORTHWEST INDIANA INTO THE
AFTERNOON AND PERSIST OVERNIGHT. AT THIS POINT THE BULK OF THE
ACTIVITY SHOULD REMAIN EAST OF GYY BUT WILL EVENTUALLY PIVOT
WESTWARD SUNDAY MORNING SO A PERIOD OF SNOW SHOWERS MAY OCCUR
THERE AT THAT TIME. THE BAND LOOKS TO PIVOT FURTHER WEST THROUGH
MIDDAY SUNDAY LEADING TO SNOW/IFR VSBY POTENTIAL AT ORD/MDW/DPA
THROUGH THE AFTERNOON.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM-HIGH CONFIDENCE IN SEEING
GUSTS AROUND 35 KT.
* HIGH CONFIDENCE IN SCATTERED SNOW SHOWERS OCCURRING THIS
MORNING...OCNLLY REDUCING VIS TO IFR OR LIFR. LOWEST VIS WILL
LIKELY BE BRIEF. LOW CONFIDENCE DURATION OF VIS RESTRICTION TO
IFR OR LIFR.
* HIGH CONFIDENCE IN GENERAL CIG TREND AND SCATTERING THIS
AFTERNOON. INTERMITTENT LOWER END MVFR CIGS IN HEAVIER
SHSN...OCNL LOWER END VFR CIGS MAY OCCUR THROUGH THE MORNING AS
WELL.
* CONFIDENCE IN SNOW FORECAST FOR SUNDAY.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO
NORTHWEST WINDS.
FRIDAY...VFR. SOUTHWEST WINDS.
MDB
&&
.MARINE...
317 AM CST
LOW PRESSURE JUST EAST OF LAKE SUPERIOR OR OVER NORTHERN GEORGIAN
BAY WILL MOVE SOUTHEAST TO THE SOUTHERN NEW ENGLAND COAST INTO
TONIGHT WHILE STRENGTHENING. VERY STRONG HIGH PRESSURE OVER THE
CANADIAN PRAIRIES WILL SETTLE SOUTHWARD INTO THE MID AND UPPER
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES INTO SUNDAY.
WINDS ARE SHIFTING FROM SOUTHWEST TO NORTHWEST AS A STRONG COLD
FRONT PUSHES SOUTHWARD DOWN THE LAKE THIS MORNING. WITH THE LOW
DEEPENING AND THE VERY STRONG HIGH ALLOWING FOR AN INCREASING
PRESSURE GRADIENT AND THEN COMBINING WITH THE STRONG COLD
ADVECTION BEHIND THE FRONT...WINDS WILL QUICKLY RAMP UP EARLY THIS
MORNING. PEAK WINDS ARE EXPECTED FROM MID/LATE MORNING THROUGH THE
AFTERNOON BEFORE SLOWLY EASING. 50 KT GUSTS LOOK LIKELY ACROSS
MUCH OF THE LAKE...ESPECIALLY THE SOUTHERN TWO-THIRDS...FROM LATE
MORNING THROUGH THE AFTERNOON. WITH ROUGHLY 6 HOURS OF GALES
EXPECTED PRIOR TO THE STORM FORCE WINDS...HAVE OPTED TO KEEP A
GALE WARNING IN EFFECT OUT THE GATE UNTIL A STORM WARNING TAKES
OVER AT 15Z FOR THE OPEN WATERS. HAVE THEN KEPT THE EXISTING GALE
WARNING FROM MID EVENING INTO THE OVERNIGHT. WILL KEEP NEARSHORE
AREAS IN A GALE...WITH STORM FORCE WINDS MORE LIKELY TO THE
EAST...BUT WILL MENTION POSSIBLE STORM FORCE GUSTS FOR THE INDIANA
WATERS. BETWEEN THE WINDS AND WAVES HEAVY FREEZING SPRAY WILL
OCCUR AND HAVE MAINTAINED THE HEAVY FREEZING SPRAY WARNING.
THE HIGH MOVES ACROSS THE GREAT LAKES SUNDAY THROUGH MONDAY WHICH
WILL LEAD TO WINDS WHICH WILL TURN EASTERLY SUNDAY AND SUNDAY NIGHT
BEFORE SOUTHWEST WINDS TAKE OVER AHEAD OF THE NEXT SERIES OF LOW
PRESSURE SYSTEMS. THIS WILL MEAN ANOTHER PERIOD OF NORTHERLY WINDS
AS WELL AS VERY COLD TEMPERATURES BY WEDNESDAY. HIGH PRESSURE IS
THEN EXPECTED TO RETURN LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...8 PM SATURDAY TO 9 AM SUNDAY.
IN...WIND ADVISORY...INZ001 UNTIL 6 PM SATURDAY.
WIND CHILL ADVISORY...INZ001-INZ010-INZ011-INZ019...8 PM
SATURDAY TO 9 AM SUNDAY.
WINTER STORM WARNING...INZ002 UNTIL 9 AM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM SATURDAY.
GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM SATURDAY TO 3 AM
SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SUNDAY.
STORM WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 3
AM SUNDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
552 AM CST Sat Feb 14 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST SAT FEB 14 2015
The Arctic cold front has reached southeastern Iowa and it should
reach near the Illinois river around sunrise, then progress across
the remainder of our counties this morning. The 00z models continue
to show a band of snow showers along and behind the front, with the
higher accumulations concentrating on the southwestern half of our
forecast area this morning. The upstream radar and satellite images
seem to be correlating well with the RAP area of 700-850mb
frontogenetic forcing. The forecast soundings still show limited
deep layer moisture, with disjointed saturated layers during the
morning. Dry air will likely limit the snowfall potential of the
system, but narrow bands of enhanced lift could linger in localized
areas as the mid-level forcing advances across C IL. Isolated bands
of up to 1 inch can not be ruled out in those cases, but most areas
should stay below a half inch, with some areas just seeing trace
amounts. Pinpointing exact locations of the bands is difficult even
this close to the event, and ongoing evaluation of correlating RAP
F-gen with radar and satellite will be needed through the morning to
keep any localized bands of heavier snow covered in the gridded
forecast.
Have advanced a band of likely PoPs this morning across our
southwest areas, but also included an hour or two of likely PoPs as
far north as Lincoln to Paris. Chance PoPs were included for at
least a couple hours in all of our northern counties at some point
this morning when the F-gen and moisture best coincide.
Temps will be steady or falling through the day. High temps for this
calendar day most likely will occur early this morning ahead of the
cold front. Strong pressure rises this afternoon will cause blustery
northwest winds to develop, with sustained speeds of 20-30 mph and a
few gusts around 40 mph. Wind chills by late afternoon will dip
below zero across all of our area, with -10 to -15F north of Peoria
already by 00z/6pm.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 330 AM CST SAT FEB 14 2015
Vigorous short wave to track into the mid Atlantic states this
evening and deepen a very strong surface low off the New England
coast tonight. This to bring yet another blizzard to coastal New
England including Boston tonight into Sunday. But for IL the main
story will be the bitter cold temperatures and wind chills. Will
issue a wind chill advisory tonight starting at 6 pm and go until 9
am Sunday for areas from Canton to Lincoln to Terre Haute northeast
where wind chills get down to 15-20 below zero. Lows overnight range
from zero to 5 below from Lincoln and Champaign north to 0 to 5
above south from I-72 south.
Strong 1046 mb arctic high pressure over nw Manitoba to weaken to
1035 mb as it drifts into the Great Lakes region Sunday afternoon.
Meanwhile a weak northern stream short wave will dive se from the
Pacific Northwest into the MO valley Sunday evening and bring chance
of light snow and flurries to areas sw of Lincoln later Sunday
afternoon into Sunday night. Snow accumulations of a dusting to up
to a half inch sw third of CWA possible with better chances of light
snow accumulations over sw and southern IL. Cold highs Sunday in the
teens. Lows Sunday night around 5F from I-74 ne to around 10F sw
CWA.
Dry conditions prevail Monday and Monday night with surface ridge
over IL with partly to mostly cloudy skies. Highs in mid to upper
20s which is still 10-15 degrees below normal for mid February.
00Z models continue to keep a stronger southern stream wx system
south of central IL Tue with surface low over southern MS river
valley. Have just chance of flurries far sw/southern counties on
Tue. Another surge of arctic air arrives Tue night through Wed night
with wind chills reaching near or a bit colder than 15 below over
northern counties. Dry conditions prevail rest of the week as temps
modify into low to mid 30s Friday afternoon.
The Climate Prediction Center (CPC) Day 8-14 Temperature Outlook for
Feb 21-27th has IL in a greater than 80% chance of below normal
temperatures, and this covers the Great Lakes region including IN/OH.
So winter`s grip looks to continue across the region the rest of the
month as upper level trof generally prevails over eastern North America
east of the Rockies.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 551 AM CST SAT FEB 14 2015
Low VFR cigs will start off the morning, with light snow showers
developing under a band of 700-850mb frontogenesis. The better
chances for steadier snows and light snow accums should be in our
southern counties, including SPI and possibly DEC. Have put MVFR
cigs in those locations this morning during snow showers and
reduced vis to 2SM at times. Isolated bands of heavier snows could
develop, where visibility dips to less than a mile as fluffy snow
falls, but chances are to low to pin-point them occurring at any
TAF site. Snow showers will diminish by 18z, with a few flurries
possibly lingering early this afternoon in eastern areas, possibly
including DEC and CMI. Low VFR cloud cover may become SCT-BKN this
afternoon as dry air begins to mix down into the boundary layer,
creating cloud streets of strato-cu.
Winds will start out WNW in the 10-15kt range, but will increase
to 20-25kt and gusting to 35 kt later this morning and this
afternoon behind the cold front. Strong wind gusts could continue
this evening, but should diminish by 06z. However, sustained
12-15kt is expected through the end of the TAF period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 6 PM this evening to 9 AM CST Sunday
FOR ILZ027>031-036>038-041>046-055-057.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS BUFFALO NY
959 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND COLD TEMPERATURES WILL
BE A LIFE THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED
FROM THE SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM AND AN ASSOCIATED ARCTIC FRONT MOVES ACROSS THE
REGION. STRONG WINDS AND BITTERLY COLD ARCTIC AIR WILL POUR INTO THE
REGION BEHIND THIS SYSTEM.
AT 1000 AM...BUFFALO RADAR SHOWING A CONVERGENCE BOUNDARY ACROSS
NORTHERN ERIE COUNTY WHICH IS PRODUCING A BAND OF VERY HEAVY
SNOW...WITH SNOWFALL RATES UP TO 3 INCHES PER HOUR. UNTIL THE FRONT
REACHES THE AREA TOWARD NOON THIS BAND WILL REMAIN NEARLY STATIONARY.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING
RAPIDLY ONCE IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL
INCREASE RAPIDLY WITH THE PASSAGE OF THIS LOW AND AN ASSOCIATED
FRONTAL BOUNDARY...WITH A QUICK BURST OF SNOW EXPECTED ALONG THIS.
MEANWHILE...NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW JUST BEHIND THE WIND SHIFT. A HRRR WEIGHTED
CONSENSUS OF MESOSCALE GUIDANCE BRINGS THIS INTO BUF-JHW AROUND NOON
AND ROC-ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE FRONT...THERE WILL BE A SMALL AREA
OF UPPER LEVEL DIFFLUENCE HEAD OF THE 500 MB LOW WHICH TRAILS THE
SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
A CONSENSUS FORECAST BRINGING ENHANCED SNOWFALL TO THE FINGER LAKES
REGION AND INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO BRING SNOWFALL RATES OF 1 TO 2 INCHES
AN HOUR AND PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE
WITH GUSTY SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...THERE
WILL BE A REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS.
THIS SHOULD ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE
ONTARIO...WITH AMPLE MOISTURE BENEATH THE BACK OF THE UPPER LOW
TO OFFSET THE STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND
CHILLS WILL COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST
DANGEROUS CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25
TO 35 BELOW LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS
AND MOST SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE
ONTARIO WHERE NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST. HAVE
ALSO TWEAKED UP SNOWFALL AMOUNTS FOR BUFFALO TO ACCOUNT FOR THE
LOCALIZED CONVERGENCE BOUNDARY WHICH SETTLED ACROSS THE CITY EARLY
THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
ONE OF THE COLDEST DAYS IN DECADES WILL START THIS TIME PERIOD AS A
LOBE OF -25C TO -27C AIR AT 850 HPA REMAINS ACROSS THE REGION...WITH A
BITING NORTHWEST WIND. TO ADD TO THE EXTREME BITTERNESS...SNOW
SHOWERS WILL BE FALLING THROUGH THE DAY SOUTH OF LAKE ONTARIO.
FOR THE EXTREME TEMPERATURES...
SUNDAY NORTHWEST WINDS WILL CONTINUE TO BRING A FRESH COLD AIRMASS
ACROSS OUR REGION...WITH -25C TO -27C 850 HPA TEMPERATURES AND CAA
ADVECTION THROUGH THE DAY BRINGING -25C AIR AS LOW AS JUST A FEW
HUNDRED FEET ABOVE THE SURFACE. NAEFS MEAN TEMPERATURE AND RETURN
INTERVALS GIVE THIS 850 HPA TEMPERATURES AT LEAST A ONCE IN 10 YEAR
OCCURRENCE. GIVEN THAT TEMPERATURES OF -26C OR LOWER HAVE BEEN
MEASURED ONLY 12 TIMES IN THE MONTH OF FEBRUARY VIA BUFFALO BALLOON
SOUNDINGS (TAKEN TWICE A DAY) SINCE 1948...WE ALSO VERIFY THAT THIS
AIRMASS OCCURS ABOUT ONCE EVERY DECADE OR SO. IN FACT THE COLDEST
850 HPA TEMPERATURE MEASURED VIA BUFFALO BALLOON SOUNDING (TAKEN AT
12Z AND 00Z) IN THE MONTH OF FEBRUARY IS -27.8C BACK ON 12Z FEBRUARY
1, 1971.
THE ARCTIC AIRMASS WILL CONTINUE THE SUBFREEZING TEMPERATURES
THROUGH THE DAY ON SUNDAY...WITH DAYLIGHT HIGHS 0F TO -5F ACROSS THE LAKE
PLAINS AND DOWN TO THE NEGATIVE TEENS IN THE SOUTHERN TIER AND UPON
THE TUG HILL REGION. THESE SUBFREEZING TEMPERATURES WILL ONLY DIP
FARTHER DOWN SUNDAY NIGHT AS HIGH PRESSURE FROM THE CENTRAL GREAT
LAKES BUILDS TOWARDS THE REGION. AS SKIES CLEAR AWAY FROM THE
SOUTHERN LAKE ONTARIO SHORELINE...AND WINDS BECOME LIGHT AND
VARIABLE...SURFACE AIR TEMPERATURES OVER A FRESH AND DEEP SNOWPACK
WILL PLUMMET TO NEAR 10 BELOW ACROSS THE LAKE PLAINS...WITH
WIDESPREAD -20S IN THE SOUTHERN TIER AND PERHAPS AS LOW AS -30F
BELOW IN THE NORTH COUNTRY...INCLUDING THE WATERTOWN AIRPORT. THESE
AIR TEMPERATURES LATE SUNDAY NIGHT AND EARLY MONDAY MORNING WILL
DROP TO NEAR RECORD LEVELS FOR THE DATE OF FEBRUARY 16TH. PLEASE SEE
CLIMATE SECTION BELOW FOR VALUES.
FOR THESE SUNDAY NIGHT TEMPERATURES TO COME TO FRUITION...OUR WINDS
MUST BE LIGHT...AND A LIGHT WIND WILL ONLY NUDGE WIND CHILLS LOWER.
WIND CHILLS SUNDAY NIGHT WILL RANGE FROM -25 TO -35 BELOW...AND
ADDITIONAL HEADLINES WILL LIKELY BE NEEDED SUNDAY NIGHT FOR THESE
VERY LOW WIND CHILLS. IF WINDS WERE TO REMAIN STEADY AROUND 10
MPH...OVERNIGHT LOWS WILL LIKELY NOT BE AS LOW...THOUGH WITH THE
STRONGER WINDS WIND CHILLS VALUES WILL STILL BE IN THE -25 TO -35
BELOW RANGE.
MONDAY HIGH PRESSURE WILL ADVANCE ACROSS THE EASTERN GREAT LAKES
REGION. WARMING ALOFT WITH 850 HPA TEMPERATURES RISING TO THE
NEGATIVE TEENS WILL ALLOW FOR MANY AREAS TO RISE ABOVE 0F FOR A FEW
HOURS. THE LIGHT WINDS AND VERY LOW MIXING HEIGHTS WILL PROBABLY
KEEP MOST AREAS BELOW 5F THOUGH.
AS THIS HIGH PRESSURE SCOOTS EASTWARD MONDAY NIGHT A LIGHT SOUTHERLY
FLOW WILL DEVELOP...FIRST ACROSS WESTERN NEW YORK AND LATER ACROSS
THE NORTH COUNTRY. MOST AREAS ACROSS WNY WILL DROP BACK TO NEAR
0F...WHICH IS NOT MUCH OF A DROP CONSIDERING DAYTIME HIGHS WILL ONLY
BE IN THE LOW SINGLE DIGITS DURING THE DAYTIME. TO THE EAST WHERE
THE SOUTHERLY FLOW WILL DEVELOP LATER OVERNIGHT TEMPERATURES WILL
LIKELY DROP 5 TO PERHAPS 10 DEGREES BELOW ZERO. MID AND HIGH LEVEL
CLOUDS WILL BEGIN TO REACH THE REGION LATE OVERNIGHT...WHICH WILL
ALSO AID IN MAINTAINING LOWS NOT AS HARSH AS THE PRIOR NIGHT.
FOR THE SNOWFALL...
SUNDAY SNOW WILL CONTINUE TO FALL ACROSS THE REGION. ALOFT WEAK
ISENTROPIC UPGLIDE WILL BE PRESENTING ENOUGH LIFT TO GENERATE SNOW
SHOWERS...ACROSS THE TUG HILL EAST OF LAKE ONTARIO...AS WELL AS
AREAS SOUTH OF LAKE ONTARIO. THIS UPGLIDE...SEEN AT THE VERY LOW
255K SURFACE...WILL CONTINUE LIGHT SYNOPTIC SNOW SHOWERS INTO SUNDAY
NIGHT BEFORE THE ISENTROPIC SURFACE FLATTENS WITH THE APPROACHING
AREA OF HIGH PRESSURE.
WITHIN THIS SYNOPTIC SNOW WILL BE BANDS OF HEAVIER SNOWFALL ALONG
THE SOUTHERN LAKE ONTARIO SHORELINE. THIS CURRENT COLD AIRMASS HAS
LIKELY SHRUNK THE OPEN WATERS ON LAKE ONTARIO TO WELL LESS THAN 50
PERCENT...BUT THERE SHOULD STILL BE ENOUGH OPEN WATERS AND THERMAL
HEAT FLUX THROUGH THE THIN ICE TO CREATE LOW LEVEL INSTABILITY AND
ALLOW FOR LAKE EFFECT SNOW SHOWERS TO FALL. A LACKING SNOW CRYSTAL
GROWTH ZONE WILL LIKELY KEEP SNOWFLAKES TO THE SMALL SCALE...WITH 1
TO 2 INCHES OF ADDITIONAL SNOW SUNDAY...DROPPING TO AROUND AN INCH
OVERNIGHT AS LAKE EFFECT SNOWS BECOME THE DOMINATE CHARACTERISTIC OF
THE SNOW...AND EVEN THIS ACTIVITY WILL BE WANING THROUGH THE NIGHT
AS HIGH PRESSURE AND DRIER AIR ADVANCES TOWARDS THE REGION. BACKING
WINDS WILL BRING THESE NOW WEAKEN BANDS OF SNOW TOWARDS SOUTHEAST
AND THEN EAST OF LAKE ONTARIO MONDAY NIGHT WITH ACTIVITY LIKELY
ENDED BY THE END OF MONDAY NIGHT.
BLOWING SNOW WILL STILL BE A MAJOR CONCERN SUNDAY AS NORTHWEST WINDS
CONTINUE THE BLOWING AND DRIFTING OF SNOW ACROSS ROADWAYS. OPEN
AREAS SOUTH OF LAKE ONTARIO WILL EXPERIENCE VERY LOW VISIBILITIES AT
TIMES AS WINDS GUST 30 TO 35 MPH. THESE GUSTS WILL BE LOWER TOWARDS
THE STATE LINE...AND THE MORE FORESTED SOUTHERN TIER WILL LOWER
THE BLOWING AND DRIFTING OF SNOW.
FOR THE NORTH COUNTRY THE BEST CHANCES FOR SNOW WILL COME SUNDAY
WITH THE ISENTROPIC UPGLIDE FLOW. AFTER THIS...THE REGION WILL
LIKELY REMAIN DRY THROUGH THIS TIME PERIOD...WITH MAINLY CLEAR
SKIES.
A CLIMATE NOTE...OUR THREE MAIN CLIMATE SITES (BUFFALO, ROCHESTER,
WATERTOWN) ALL CONSIDER A CLIMATE DAY FROM MIDNIGHT TO MIDNIGHT.
THUS IF AIR TEMPERATURES ARE STILL ABOVE ZERO AT MIDNIGHT LEADING
INTO SUNDAY THESE ABOVE ZERO AIR TEMPERATURES WILL BE CONSIDERED THE
HIGH FOR THE DAY...EVEN IF THE DAYLIGHT HOURS SUNDAY REMAIN WELL
BELOW ZERO. FOR SUNDAY...IT APPEARS MUCH OF THE REGION MAY REMAIN
ABOVE ZERO AT MIDNIGHT...AND THUS THESE VALUES WILL BE THE OFFICIAL
HIGH TEMPERATURES FOR SUNDAY.
ADDITIONAL TEMPERATURE STATS WILL BE FOUND BELOW IN THE CLIMATE
SECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO NEW ENGLAND
THROUGH WEDNESDAY. THE 00Z GFS CONTINUES TO REMAIN FARTHER WESTWARD
WITH THIS SYSTEM AND ITS TRACK THAN THE 00Z ECMWF. FOR NOW WILL
CONTINUE WITH CHANCES POPS. REGARDLESS OF THE TRACK ANOTHER ROUND OF
COLD AIR WILL FOLLOW BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH
FRIDAY...WITH THE POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT
OFF OF LAKE ONTARIO. WHILE THE NEXT ROUND OF COLD DOES NOT APPEAR AS
POTENT AS THE CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP
TEMPERATURES WELL BELOW NORMAL.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
CONDITIONS WILL GENERALLY DETERIORATE FROM W-E THIS MORNING AS LOW
PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY DIVE ACROSS THE
REGION. EXPECT WIDESPREAD IFR CONDITIONS...WITH LOCALLY LOWER
CONDITIONS WITH THE WIND SHIFT. GUSTY WINDS WILL MOVE IN BEHIND THE
FRONT WITH BLOWING SNOW ALSO LOWERING VSBY.
AFTER THIS...THERE MAY BE A BRIEF IMPROVEMENT LATE AFTERNOON AND
EARLY EVENING AS SOMEWHAT DRIER AIR MOVES IN. ANY IMPROVEMENT
SHOULD BE SHORT LIVED...WITH ANOTHER BLAST OF EVEN COLDER AIR
FORECAST TO DROP SOUTH OF LAKE ONTARIO BETWEEN 03Z AND 06Z. THIS
WILL ENHANCE LAKE EFFECT SNOW SOUTH OF THE LAKE. THIS COMBINED
WITH BLOWING SNOW WILL LOWER VSBY TO 1SM OR LESS AT BUF/ROC/IAG.
CONDITIONS WILL GRADUALLY IMPROVE LATE TONIGHT AS DRIER AIR
GRADUALLY WORKS IN. DUE TO THE VERY COLD CONDITIONS...EVEN LIGHT
SNOW SHOULD FALL AS VERY SMALL CRYSTALS WHICH WILL LOWER VSBY SIGNIFICANTLY.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.CLIMATE...
A FEW TEMPERATURE CLIMATE STATS BELOW...
DAILY RECORDS:
SUNDAY, FEBRUARY 15TH
MINIMUM LOW MAXIMUM
BUFFALO -16F (1943) 4F (1943)
ROCHESTER -14F (1943) 4F (1943)
WATERTOWN -30F (1987) 1F (1987)
MONDAY, FEBRUARY 16TH
MINIMUM LOW MAXIMUM
BUFFALO -8F (1904) 0F (1904)
ROCHESTER -7F (2004) -1F (1904)
WATERTOWN -24F (1963) 2F (2003)
ONE WAY TO VIEW THIS UPCOMING COLD OUTBREAK IS TO LOOK AT AVERAGE
TEMPERATURES FOR A DAY (AVERAGE OF MAXIMUM AND MINIMUM TEMPERATURE
FOR THE DAY).
LAST TIME A CLIMATE SITE HAD AN AVERAGE TEMPERATURE BELOW ZERO...
BUFFALO JANUARY 19, 1994 HIGH: -1 LOW: -10 AVERAGE: -5.5F
ROCHESTER JANUARY 14, 2004 HIGH: 4 LOW: -6 AVERAGE: -1.0F
RECENT TIMES A CLIMATE SITE HAD A MINIMUM TEMPERATURE MINUS TEN
OR LOWER...
BUFFALO JANUARY 6, 1996 LOW: -10F
JANUARY 19, 1994 LOW: -10F
JANUARY 21, 1985 LOW: -10F
JANUARY 16, 1984 LOW: -10F
JANUARY 17, 1982 LOW: -16F
ROCHESTER JANUARY 21, 2005 LOW: -10F
JANUARY 10, 2004 LOW: -12F
JANUARY 31, 1994 LOW: -10F
JANUARY 19, 1994 LOW: -11F
JANUARY 16, 1994 LOW: -17F
THOUGH THE POSSIBILITY OF A HIGH TEMPERATURE REMAINING BELOW ZERO
FOR A 24-HR DAY PERIOD IS NOW LESS LIKELY HERE ARE THE LAST TIME
CLIMATE SITES DID ACHIEVE THIS FEAT.
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/TMA
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL
MARINE...APFFEL
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
715 AM EST SAT FEB 14 2015
.SYNOPSIS...
A STRENGTHENING LOW WILL BRING SNOW AND BLOWING SNOW TODAY AND
TONIGHT BEFORE THE COLDEST AIR OF THE SEASON SURGES INTO THE AREA
FOR SUNDAY AND MONDAY. DAYTIME HIGHS ON SUNDAY MAY NOT EVEN GET
ABOVE ZERO...WITH DANGEROUSLY COLD WIND CHILLS. THE COLD WEATHER
WILL CONTINUE INTO NEXT WEEK WITH MORE BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEXT ROUND OF WINTRY WEATHER MAY NOT BE THE HEAVIEST SNOW OF THE
SEASON...BUT THE SNOW...BLOWING SNOW...AND COLD TEMPERATURES WILL
BE A LIFE THREATENING COMBINATION. IF A VEHICLE BECOMES DISABLED
FROM THE SNOWY CONDITIONS...PASSENGERS WILL HAVE TO CONTEND WITH
DANGEROUSLY COLD WIND CHILLS.
THE EXTREME CONDITIONS WILL NOT START UNTIL A STRENGTHENING LOW
PRESSURE SYSTEM AND AN ASSOCIATED ARCTIC FRONT MOVES ACROSS THE
REGION. STRONG WINDS AND BITTERLY COLD ARCTIC AIR WILL POUR INTO
THE REGION BEHIND THIS SYSTEM. UNTIL THEN...EXPECT MAINLY LIGHT
SNOWFALL WHICH WILL INCREASE IN INTENSITY A BIT THROUGH THE
MORNING HOURS AS MOISTURE AND SURFACE CONVERGENCE INCREASE AHEAD
OF THE LOW. AT 700 AM...RADAR SHOWS A CONVERGENCE BOUNDARY
DEVELOPING ACROSS AND JUST NORTH OF BUFFALO WHICH WILL PRODUCE A
NARROW BAND OF MODERATE TO HEAVY SNOW UNTIL THE FRONT REACHES THE
AREA LATER THIS MORNING. THROUGH NOON TODAY...EXPECT 1 TO 3
INCHES OF SNOW WEST OF ROCHESTER...WITH THE GREATEST AMOUNTS
ACROSS THE BUFFALO METRO AREA. THROUGH NOON...SNOW SHOULD BE LIGHT
EAST OF ROCHESTER...GENERALLY AN INCH OR LESS.
A VIGOROUS UPPER LOW AND WEAKER SURFACE REFLECTION WILL DIVE ACROSS
THE REGION TODAY...WITH THE SURFACE LOW EVENTUALLY DEEPENING
RAPIDLY ONCE IT REACHES THE NEW ENGLAND COAST TONIGHT. WINDS WILL
INCREASE RAPIDLY WITH THE PASSAGE OF THIS LOW AND AN ASSOCIATED
FRONTAL BOUNDARY...WITH A QUICK BURST OF SNOW EXPECTED ALONG THIS.
MEANWHILE...NORTHWEST WINDS GUSTING TO 40 MPH WILL RESULT IN
BLOWING SNOW JUST BEHIND THE WIND SHIFT. A HRRR WEIGHTED
CONSENSUS OF MESOSCALE GUIDANCE BRINGS THIS INTO BUF-JHW AROUND
NOON AND ROC- ELZ AROUND 2 PM.
IN ADDITION TO LIFT WITH THE FRONT...THERE WILL BE A SMALL AREA
OF UPPER LEVEL DIFFLUENCE HEAD OF THE 500 MB LOW WHICH TRAILS THE
SURFACE LOW. GUIDANCE DIFFERS A BIT ON WHERE THIS WILL BE...WITH
A CONSENSUS FORECAST BRINGING ENHANCED SNOWFALL TO THE FINGER LAKES
REGION AND INTO OSWEGO COUNTY LATE THIS AFTERNOON AND EARLY
EVENING. THIS IS LIKELY TO BRING SNOWFALL RATES OF 1 TO 2 INCHES
AN HOUR AND PRODUCE NEAR WHITEOUT CONDITIONS SINCE IT WILL COINCIDE
WITH GUSTY SURFACE WINDS.
OUTSIDE OF THIS AREA...EXPECT A BRIEF LULL IN SNOW INTENSITY LATE
AFTERNOON AND EARLY EVENING WITH WESTERN NEW YORK UNDERNEATH THIS
CLOSED UPPER LOW. ONCE THIS UPPER LOW MOVES TO OUR EAST...THERE
WILL BE A REINFORCING SHOT OF COLD AIR AND AN UPTICK IN WINDS.
THIS SHOULD ENERGIZE LAKE EFFECT SNOWS SOUTH OF LAKE
ONTARIO...WITH AMPLE MOISTURE BENEATH THE BACK OF THE UPPER LOW
TO OFFSET THE STRONG WIND SPEEDS. THIS IS WHEN BITTERLY COLD WIND
CHILLS WILL COMBINE WITH SNOW AND BLOWING SNOW TO CREATE THE MOST
DANGEROUS CONDITIONS IN MOST AREAS. WIND CHILLS WILL PLUMMET TO 25
TO 35 BELOW LATE TONIGHT INTO SUNDAY MORNING. THE STRONGEST WINDS
AND MOST SIGNIFICANT BLOWING SNOW WILL BE JUST SOUTH OF LAKE
ONTARIO WHERE NEAR WHITEOUT CONDITIONS ARE POSSIBLE.
OVERALL...THE LATEST FORECAST HAS ONLY MADE MINOR ADJUSTMENTS TO
STORM TOTAL SNOWFALL. WITH THE STRONG WINDS AND DEEP
MOISTURE...EXPECT UPSLOPING WELL SOUTH OF THE LAKE ONTARIO SHORELINE
TO ENHANCE SNOW TOTALS A BIT. THE GREATEST AMOUNTS SHOULD BE FROM
ROCHESTER TOWARD SYRACUSE...WHERE 8 TO 14 INCHES IS FORECAST. HAVE
ALSO TWEAKED UP SNOWFALL AMOUNTS FOR BUFFALO TO ACCOUNT FOR THE
LOCALIZED CONVERGENCE BOUNDARY WHICH SETTLED ACROSS THE CITY EARLY
THIS MORNING.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
ONE OF THE COLDEST DAYS IN DECADES WILL START THIS TIME PERIOD AS A
LOBE OF -25C TO -27C AIR AT 850 HPA REMAINS ACROSS THE REGION...WITH A
BITING NORTHWEST WIND. TO ADD TO THE EXTREME BITTERNESS...SNOW
SHOWERS WILL BE FALLING THROUGH THE DAY SOUTH OF LAKE ONTARIO.
FOR THE EXTREME TEMPERATURES...
SUNDAY NORTHWEST WINDS WILL CONTINUE TO BRING A FRESH COLD AIRMASS
ACROSS OUR REGION...WITH -25C TO -27C 850 HPA TEMPERATURES AND CAA
ADVECTION THROUGH THE DAY BRINGING -25C AIR AS LOW AS JUST A FEW
HUNDRED FEET ABOVE THE SURFACE. NAEFS MEAN TEMPERATURE AND RETURN
INTERVALS GIVE THIS 850 HPA TEMPERATURES AT LEAST A ONCE IN 10 YEAR
OCCURRENCE. GIVEN THAT TEMPERATURES OF -26C OR LOWER HAVE BEEN
MEASURED ONLY 12 TIMES IN THE MONTH OF FEBRUARY VIA BUFFALO BALLOON
SOUNDINGS (TAKEN TWICE A DAY) SINCE 1948...WE ALSO VERIFY THAT THIS
AIRMASS OCCURS ABOUT ONCE EVERY DECADE OR SO. IN FACT THE COLDEST
850 HPA TEMPERATURE MEASURED VIA BUFFALO BALLOON SOUNDING (TAKEN AT
12Z AND 00Z) IN THE MONTH OF FEBRUARY IS -27.8C BACK ON 12Z FEBRUARY
1, 1971.
THE ARCTIC AIRMASS WILL CONTINUE THE SUBFREEZING TEMPERATURES
THROUGH THE DAY ON SUNDAY...WITH DAYLIGHT HIGHS 0F TO -5F ACROSS THE LAKE
PLAINS AND DOWN TO THE NEGATIVE TEENS IN THE SOUTHERN TIER AND UPON
THE TUG HILL REGION. THESE SUBFREEZING TEMPERATURES WILL ONLY DIP
FARTHER DOWN SUNDAY NIGHT AS HIGH PRESSURE FROM THE CENTRAL GREAT
LAKES BUILDS TOWARDS THE REGION. AS SKIES CLEAR AWAY FROM THE
SOUTHERN LAKE ONTARIO SHORELINE...AND WINDS BECOME LIGHT AND
VARIABLE...SURFACE AIR TEMPERATURES OVER A FRESH AND DEEP SNOWPACK
WILL PLUMMET TO NEAR 10 BELOW ACROSS THE LAKE PLAINS...WITH
WIDESPREAD -20S IN THE SOUTHERN TIER AND PERHAPS AS LOW AS -30F
BELOW IN THE NORTH COUNTRY...INCLUDING THE WATERTOWN AIRPORT. THESE
AIR TEMPERATURES LATE SUNDAY NIGHT AND EARLY MONDAY MORNING WILL
DROP TO NEAR RECORD LEVELS FOR THE DATE OF FEBRUARY 16TH. PLEASE SEE
CLIMATE SECTION BELOW FOR VALUES.
FOR THESE SUNDAY NIGHT TEMPERATURES TO COME TO FRUITION...OUR WINDS
MUST BE LIGHT...AND A LIGHT WIND WILL ONLY NUDGE WIND CHILLS LOWER.
WIND CHILLS SUNDAY NIGHT WILL RANGE FROM -25 TO -35 BELOW...AND
ADDITIONAL HEADLINES WILL LIKELY BE NEEDED SUNDAY NIGHT FOR THESE
VERY LOW WIND CHILLS. IF WINDS WERE TO REMAIN STEADY AROUND 10
MPH...OVERNIGHT LOWS WILL LIKELY NOT BE AS LOW...THOUGH WITH THE
STRONGER WINDS WIND CHILLS VALUES WILL STILL BE IN THE -25 TO -35
BELOW RANGE.
MONDAY HIGH PRESSURE WILL ADVANCE ACROSS THE EASTERN GREAT LAKES
REGION. WARMING ALOFT WITH 850 HPA TEMPERATURES RISING TO THE
NEGATIVE TEENS WILL ALLOW FOR MANY AREAS TO RISE ABOVE 0F FOR A FEW
HOURS. THE LIGHT WINDS AND VERY LOW MIXING HEIGHTS WILL PROBABLY
KEEP MOST AREAS BELOW 5F THOUGH.
AS THIS HIGH PRESSURE SCOOTS EASTWARD MONDAY NIGHT A LIGHT SOUTHERLY
FLOW WILL DEVELOP...FIRST ACROSS WESTERN NEW YORK AND LATER ACROSS
THE NORTH COUNTRY. MOST AREAS ACROSS WNY WILL DROP BACK TO NEAR
0F...WHICH IS NOT MUCH OF A DROP CONSIDERING DAYTIME HIGHS WILL ONLY
BE IN THE LOW SINGLE DIGITS DURING THE DAYTIME. TO THE EAST WHERE
THE SOUTHERLY FLOW WILL DEVELOP LATER OVERNIGHT TEMPERATURES WILL
LIKELY DROP 5 TO PERHAPS 10 DEGREES BELOW ZERO. MID AND HIGH LEVEL
CLOUDS WILL BEGIN TO REACH THE REGION LATE OVERNIGHT...WHICH WILL
ALSO AID IN MAINTAINING LOWS NOT AS HARSH AS THE PRIOR NIGHT.
FOR THE SNOWFALL...
SUNDAY SNOW WILL CONTINUE TO FALL ACROSS THE REGION. ALOFT WEAK
ISENTROPIC UPGLIDE WILL BE PRESENTING ENOUGH LIFT TO GENERATE SNOW
SHOWERS...ACROSS THE TUG HILL EAST OF LAKE ONTARIO...AS WELL AS
AREAS SOUTH OF LAKE ONTARIO. THIS UPGLIDE...SEEN AT THE VERY LOW
255K SURFACE...WILL CONTINUE LIGHT SYNOPTIC SNOW SHOWERS INTO SUNDAY
NIGHT BEFORE THE ISENTROPIC SURFACE FLATTENS WITH THE APPROACHING
AREA OF HIGH PRESSURE.
WITHIN THIS SYNOPTIC SNOW WILL BE BANDS OF HEAVIER SNOWFALL ALONG
THE SOUTHERN LAKE ONTARIO SHORELINE. THIS CURRENT COLD AIRMASS HAS
LIKELY SHRUNK THE OPEN WATERS ON LAKE ONTARIO TO WELL LESS THAN 50
PERCENT...BUT THERE SHOULD STILL BE ENOUGH OPEN WATERS AND THERMAL
HEAT FLUX THROUGH THE THIN ICE TO CREATE LOW LEVEL INSTABILITY AND
ALLOW FOR LAKE EFFECT SNOW SHOWERS TO FALL. A LACKING SNOW CRYSTAL
GROWTH ZONE WILL LIKELY KEEP SNOWFLAKES TO THE SMALL SCALE...WITH 1
TO 2 INCHES OF ADDITIONAL SNOW SUNDAY...DROPPING TO AROUND AN INCH
OVERNIGHT AS LAKE EFFECT SNOWS BECOME THE DOMINATE CHARACTERISTIC OF
THE SNOW...AND EVEN THIS ACTIVITY WILL BE WANING THROUGH THE NIGHT
AS HIGH PRESSURE AND DRIER AIR ADVANCES TOWARDS THE REGION. BACKING
WINDS WILL BRING THESE NOW WEAKEN BANDS OF SNOW TOWARDS SOUTHEAST
AND THEN EAST OF LAKE ONTARIO MONDAY NIGHT WITH ACTIVITY LIKELY
ENDED BY THE END OF MONDAY NIGHT.
BLOWING SNOW WILL STILL BE A MAJOR CONCERN SUNDAY AS NORTHWEST WINDS
CONTINUE THE BLOWING AND DRIFTING OF SNOW ACROSS ROADWAYS. OPEN
AREAS SOUTH OF LAKE ONTARIO WILL EXPERIENCE VERY LOW VISIBILITIES AT
TIMES AS WINDS GUST 30 TO 35 MPH. THESE GUSTS WILL BE LOWER TOWARDS
THE STATE LINE...AND THE MORE FORESTED SOUTHERN TIER WILL LOWER
THE BLOWING AND DRIFTING OF SNOW.
FOR THE NORTH COUNTRY THE BEST CHANCES FOR SNOW WILL COME SUNDAY
WITH THE ISENTROPIC UPGLIDE FLOW. AFTER THIS...THE REGION WILL
LIKELY REMAIN DRY THROUGH THIS TIME PERIOD...WITH MAINLY CLEAR
SKIES.
A CLIMATE NOTE...OUR THREE MAIN CLIMATE SITES (BUFFALO, ROCHESTER,
WATERTOWN) ALL CONSIDER A CLIMATE DAY FROM MIDNIGHT TO MIDNIGHT.
THUS IF AIR TEMPERATURES ARE STILL ABOVE ZERO AT MIDNIGHT LEADING
INTO SUNDAY THESE ABOVE ZERO AIR TEMPERATURES WILL BE CONSIDERED THE
HIGH FOR THE DAY...EVEN IF THE DAYLIGHT HOURS SUNDAY REMAIN WELL
BELOW ZERO. FOR SUNDAY...IT APPEARS MUCH OF THE REGION MAY REMAIN
ABOVE ZERO AT MIDNIGHT...AND THUS THESE VALUES WILL BE THE OFFICIAL
HIGH TEMPERATURES FOR SUNDAY.
ADDITIONAL TEMPERATURE STATS WILL BE FOUND BELOW IN THE CLIMATE
SECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST MEDIUM RANGE MODELS CONTINUING TO POINT TO A POTENTIAL
SOUTHERN STREAM STORM SYSTEM LIFTING OUT OF THE SOUTHERN PLAINS
TUESDAY...THEN PUSHING UP THE EASTERN SEABOARD INTO NEW ENGLAND
THROUGH WEDNESDAY. THE 00Z GFS CONTINUES TO REMAIN FARTHER WESTWARD
WITH THIS SYSTEM AND ITS TRACK THAN THE 00Z ECMWF. FOR NOW WILL
CONTINUE WITH CHANCES POPS. REGARDLESS OF THE TRACK ANOTHER ROUND OF
COLD AIR WILL FOLLOW BEHIND THE STORM SYSTEM FOR WEDNESDAY THROUGH
FRIDAY...WITH THE POTENTIAL FOR A PROLONGED LAKE EFFECT SNOW EVENT
OFF OF LAKE ONTARIO. WHILE THE NEXT ROUND OF COLD DOES NOT APPEAR AS
POTENT AS THE CURRENT ROUND FOR SUNDAY...IT WILL STILL KEEP
TEMPERATURES WELL BELOW NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
CONDITIONS WILL GENERALLY DETERIORATE FROM W-E THIS MORNING AS LOW
PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY DIVE ACROSS THE
REGION. EXPECT WIDESPREAD IFR CONDITIONS...WITH LOCALLY LOWER
CONDITIONS WITH THE WIND SHIFT. GUSTY WINDS WILL MOVE IN BEHIND THE
FRONT WITH BLOWING SNOW ALSO LOWERING VSBY.
AFTER THIS...THERE MAY BE A BRIEF IMPROVEMENT LATE AFTERNOON AND
EARLY EVENING AS SOMEWHAT DRIER AIR MOVES IN. ANY IMPROVEMENT
SHOULD BE SHORT LIVED...WITH ANOTHER BLAST OF EVEN COLDER AIR
FORECAST TO DROP SOUTH OF LAKE ONTARIO BETWEEN 03Z AND 06Z. THIS
WILL ENHANCE LAKE EFFECT SNOW SOUTH OF THE LAKE. THIS COMBINED
WITH BLOWING SNOW WILL LOWER VSBY TO 1SM OR LESS AT BUF/ROC/IAG.
CONDITIONS WILL GRADUALLY IMPROVE LATE TONIGHT AS DRIER AIR
GRADUALLY WORKS IN. DUE TO THE VERY COLD CONDITIONS...EVEN LIGHT
SNOW SHOULD FALL AS VERY SMALL CRYSTALS WHICH WILL LOWER VSBY SIGNIFICANTLY.
OUTLOOK...
SUNDAY...IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE
ONTARIO...MVFR ELSEWHERE.
MONDAY...A SLIGHT CHANCE OF MVFR/IFR IN SNOW SHOWERS SOUTHEAST OF
THE LAKES...OTHERWISE VFR.
TUESDAY...CHANCE OF MVFR/IFR IN SNOW SHOWERS.
&&
.MARINE...
WINDS WILL RAPIDLY INCREASE BEHIND A STRONG CLIPPER LOW THIS
AFTERNOON. ARCTIC AIR WILL BUILD ACROSS THE REGION BEHIND THIS AND A
30 KT NW FLOW SHOULD PRODUCE AMPLE WAVE ACTION FOR ANOTHER ROUND OF
HEAVY FREEZING SPRAY ON THE REMAINING OPEN WATERS OF LAKE ONTARIO.
HAVE KEPT WINDS IN THE STRONG SCA RANGE FOR NOW...BUT A FEW GUSTS TO
GALE ARE POSSIBLE WITH THE WIND SHIFT.
FOLLOWING COORDINATION...HAVE ISSUED GALE WARNINGS FOR LAKE
ERIE...WITH A FEW HOURS OF 35 KT WINDS EXPECTED BEHIND THE LOW LATE
THIS AFTERNOON AND EARLY EVENING. WINDS WILL BE STRONGEST ACROSS
CENTRAL AND WESTERN PORTIONS OF LAKE ERIE.
WINDS WILL DIMINISH SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS
TOWARD THE LOWER LAKES.
&&
.CLIMATE...
A FEW TEMPERATURE CLIMATE STATS BELOW...
DAILY RECORDS:
SUNDAY, FEBRUARY 15TH
MINIMUM LOW MAXIMUM
BUFFALO -16F (1943) 4F (1943)
ROCHESTER -14F (1943) 4F (1943)
WATERTOWN -30F (1987) 1F (1987)
MONDAY, FEBRUARY 16TH
MINIMUM LOW MAXIMUM
BUFFALO -8F (1904) 0F (1904)
ROCHESTER -7F (2004) -1F (1904)
WATERTOWN -24F (1963) 2F (2003)
ONE WAY TO VIEW THIS UPCOMING COLD OUTBREAK IS TO LOOK AT AVERAGE
TEMPERATURES FOR A DAY (AVERAGE OF MAXIMUM AND MINIMUM TEMPERATURE
FOR THE DAY).
LAST TIME A CLIMATE SITE HAD AN AVERAGE TEMPERATURE BELOW ZERO...
BUFFALO JANUARY 19, 1994 HIGH: -1 LOW: -10 AVERAGE: -5.5F
ROCHESTER JANUARY 14, 2004 HIGH: 4 LOW: -6 AVERAGE: -1.0F
RECENT TIMES A CLIMATE SITE HAD A MINIMUM TEMPERATURE MINUS TEN
OR LOWER...
BUFFALO JANUARY 6, 1996 LOW: -10F
JANUARY 19, 1994 LOW: -10F
JANUARY 21, 1985 LOW: -10F
JANUARY 16, 1984 LOW: -10F
JANUARY 17, 1982 LOW: -16F
ROCHESTER JANUARY 21, 2005 LOW: -10F
JANUARY 10, 2004 LOW: -12F
JANUARY 31, 1994 LOW: -10F
JANUARY 19, 1994 LOW: -11F
JANUARY 16, 1994 LOW: -17F
THOUGH THE POSSIBILITY OF A HIGH TEMPERATURE REMAINING BELOW ZERO
FOR A 24-HR DAY PERIOD IS NOW LESS LIKELY HERE ARE THE LAST TIME
CLIMATE SITES DID ACHIEVE THIS FEAT.
BUFFALO...
COLDEST HIGH TEMPERATURE ON RECORD...
-3 ON FEBRUARY 10, 1899 AND FEBRUARY 11, 1885
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 19, 1994
ROCHESTER...
COLDEST HIGH TEMPERATURE ON RECORD...
-4 ON JANUARY 17, 1982
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-4 ON JANUARY 17, 1982
WATERTOWN...
COLDEST HIGH TEMPERATURE ON RECORD...
-12 ON JANUARY 3, 1981
LAST TIME HIGH TEMPERATURE WAS BELOW ZERO...
-1 ON JANUARY 22, 2014
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 6 PM EST SUNDAY FOR NYZ001>006-
010>014-019-020-085.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
SUNDAY FOR NYZ007-008.
WIND CHILL WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ007-008.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR NYZ021.
WIND CHILL WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
MONDAY FOR NYZ021.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR LEZ040-041.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING
TO 6 AM EST MONDAY FOR LOZ042>044-062>064.
SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 1 AM EST MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL
MARINE...APFFEL
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EST SAT FEB 14 2015
.SYNOPSIS...HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST MOVES
OFFSHORE THIS AFTERNOON...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING OUT
OF MICHIGAN AND ILLINOIS AND TOWARD THE OHIO VALLEY...WITH A BROAD
CYCLONIC FLOW AND GRADUAL PRESSURE FALLS AHEAD OF THE FRONT. ON
WATER VAPOR IMAGERY...A LEADING MID-LEVEL SHORTWAVE WAS MOVING
THROUGH CENTRAL NORTH CAROLINA WITH NUMEROUS HIGH STRATOCU OVER
PARTS OF THE AREA ALONG AND NORTH OF ABOUT U.S. 64. BEHIND THE
SHORTWAVE THERE WAS EVIDENCE OF DECREASING MOISTURE IN THE MID-
LEVELS AHEAD OF THE MORE POTENT MID-LEVEL TROUGH MOVING SOUTH OUT OF
THE GREAT LAKES. THE LATEST HRRR WRF SEEMS TO DEPICT THE TREND OF
THE CLOUD COVER FAIRLY WELL...SOME INCREASE ESPECIALLY IN THE
NORTHERN PART OF CENTRAL NORTH CAROLINA THIS MORNING WITH CLEARING
BEHIND IT...AND SOME OF THAT WAS ALREADY OCCURRING ON VISIBLE IMAGES
JUST OF THE TRIAD AS OF THIS WRITING.
NAM AND GFS BUFR SOUNDINGS...ALONG WITH RAP SOUNDINGS...INDICATE
INCREASING MIXING TAKING PLACE DURING THE AFTERNOON AS 925MB WINDS
INCREASE TO SOLIDLY 30KT BETWEEN 18Z AND 21Z. MUCH OF THE
GUIDANCE... HOWEVER...IS ALSO CONSISTENT IN A SURFACE DEW POINT
RECOVERY IN THE SOUTHWEST FLOW TODAY. RAP 1000-850MB THICKNESSES AT
12Z THIS MORNING WERE VIRTUALLY IDENTICAL TO THE SAME THICKNESS AT
KGSO...AND WITH ENOUGH SUN IN A SOUTHWEST FLOW THOSE THICKNESSES
SUPPORT HIGHS AT LEAST IN THE LOWER TO MID 50S. IT IS INTERESTING
HOW SOME OF THE MOS GUIDANCE IS SO COLD AT KRDU COMPARED TO OTHER
SITES IN CENTRAL NORTH CAROLINA...AND RUNS OF THE LAMP MOS GUIDANCE
EVEN TO 13Z FOR THERE WERE SHOWING HIGHS ONLY IN THE LOWER
40S...WITH SUBSTANTIALLY HIGHER VALUES ELSEWHERE. ANTICIPATING
ENOUGH SUN TO WARM TEMPERATURES AND CONSIDERING THE RISE IN
TEMPERATURES POSSIBLY OUTPACING THE LOW-LEVEL DEW POINT RISE...
MINIMUM RELATIVE HUMIDITIES SHOULD BE AROUND OR JUST BELOW 25
PERCENT.
MIXING HEIGHTS RISE THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT
TRANSPORT OF SOME OF THE INCREASING WINDS ALOFT TO THE SURFACE.
CURRENTLY ANTICIPATING WIND GUSTS AT LEAST AROUND 30 MPH...THE
COMBINED FORECAST OF LOW RELATIVE HUMIDITIES AND THE WIND RESULTS IN
FIRE WEATHER CONDITIONS FROM THE TRIANGLE NORTH AND WEST SIMILAR TO
THOSE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN. AS A RESULT...
OPTED TO EXPAND THE RED FLAG WARNING TO INCLUDE MUCH OF CENTRAL
NORTH CAROLINA EXCEPT FOR THE NORTHEAST PIEDMONT...WHERE MINIMUM
RELATIVE HUMIDITIES ARE FORECAST TO BE JUST A LITTLE HIGHER COMPARED
TO THE REST OF THE AREA.
AS THE FRONT APPROACHES LATE IN THE DAY...MID-LEVEL MOISTURE
INCREASES AND LANDS IN THE -10C OR SO ZONE ON BUFR AND RAP SOUNDINGS
SUCH THAT AT LEAST ISOLATED SHOWERS ARE POSSIBLE IN THE TRIAD VERY
LATE IN THE DAY...PROBABLY AFTER 5 PM. FOLLOWING THIS...SPOTTY LIGHT
SHOWERS OR SPRINKLES MAY OVERCOME AN OTHERWISE RELATIVELY DEEP ~6
THOUSAND FT SUB-CLOUD LAYER. SIMILAR TO THURSDAY...FLURRIES OR LIGHT
SNOW MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS
DURING THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY REMAINS FOR ALL BUT THE FAR SOUTHWEST PIEDMONT...THOUGH
THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN THE ADVISORY GIVEN
THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH WINDS IMMEDIATELY
BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
WINTER WEATHER IS POSSIBLE EARLY NEXT WEEK...THOUGH CONFIDENCE
REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND TUESDAY OF
NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY CONVERGENCE
TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 700 AM SATURDAY...
LIGHT SOUTH TO SOUTHWESTERLY WINDS THIS MORNING WILL BECOME SW TO
SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW BETWEEN
MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 1055 AM SATURDAY...
AS NOTED IN THE NEAR-TERM DISCUSSION ABOVE...MIXING HEIGHTS RISE
THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT TRANSPORT OF SOME
INCREASING WINDS ALOFT TO THE SURFACE. CURRENTLY ANTICIPATING WIND
GUSTS AT LEAST AROUND 30 MPH...THE COMBINED FORECAST OF LOW RELATIVE
HUMIDITIES AND THE WIND RESULTS IN FIRE WEATHER CONDITIONS FROM THE
TRIANGLE NORTH AND WEST SIMILAR TO THOSE OVER THE SANDHILLS AND
SOUTHERN COASTAL PLAIN. AS A RESULT...OPTED TO EXPAND THE RED FLAG
WARNING TO INCLUDE MUCH OF CENTRAL NORTH CAROLINA EXCEPT FOR THE
NORTHEAST PIEDMONT...WHERE MINIMUM RELATIVE HUMIDITIES ARE FORECAST
TO BE JUST A LITTLE HIGHER COMPARED TO THE REST OF THE AREA.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE
LATER TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...SMITH
AVIATION...RAH
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
724 AM EST SAT FEB 14 2015
.SYNOPSIS...
ARCTIC HIGH PRESSURE ALONG THE SOUTH ATLANTIC COAST
WILL MOVE OFFSHORE TODAY...IN ADVANCE OF AN ARCTIC COLD FRONT THAT
WILL BLAST ACROSS OUR REGION THIS EVENING. ARCTIC HIGH PRESSURE WILL
FOLLOW AND BUILD ACROSS THE MIDDLE ATLANTIC STATES TONIGHT THROUGH
MON.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 720 AM SATURDAY...
YET ANOTHER POTENT PV ANOMALY...DRIVEN BY A 130 KT MID LEVEL JET
STREAK IN NW FLOW...WILL AMPLIFY SHARPLY FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC COAST THROUGH TONIGHT. AN ACCOMPANYING SFC LOW WILL
UNDERGO DEEPENING AND ULTIMATELY BOMB AS IT TRACKS FROM THE EASTERN
GREAT LAKES TO THE MIDDLE ATLANTIC AND NEW ENGLAND COASTS...WITH A
TRAILING ARCTIC COLD FRONT POISED TO SURGE SSE ACROSS CENTRAL NC
THIS EVENING.
AHEAD OF THE FRONT...A BREEZY AND RELATIVELY MILD SW WIND WILL GUST
BETWEEN 20 AND 30 MPH...WITH PARTLY TO MOSTLY SUNNY SKIES FOR THE
MAJORITY OF THE DAY. TEMPERATURES OFTEN PROVE WARMER THAN FORECAST
IN CASES OF STRONG SW FLOW...LIKE TODAY. WITH THAT IN MIND...AND
BASED ON RECENT RUNS OF THE HRRR AND RAP...AND WITH SUPPORT FROM THE
MAV MOS...HIGH TEMPERATURES HAVE BEEN ADJUSTED MILDER YET - INTO THE
LOWER TO MIDDLE 50S...WITH SOME UPPER 50S POSSIBLE OVER THE SOUTHERN
PIEDMONT AND SANDHILLS. SIMILAR TO WHAT OCCURRED ON THU...A
SHIELD/BAND OF BKN TO OVC STRATOCUMULUS AND PRECIPITATION WILL
SPREAD/DEVELOP EASTWARD ACROSS CENTRAL NC DURING THE LATE AFTERNOON
AND EVENING. SPOTTY LIGHT SHOWERS OR SPRINKLES MAY OVERCOME AN
OTHERWISE RELATIVELY DEEP ~6 THOUSAND FT SUB-CLOUD LAYER...MAINLY
FROM THE TRIANGLE AND POINTS NORTHEAST...IN CLOSEST PROXIMITY TO A
240 M/12 HR PRESSURE FALL CENTER FOCUSED OVER THE CHESAPEAKE BAY AND
DELMARVA AT 06Z/15TH. ALSO SIMILAR TO THU...FLURRIES OR LIGHT SNOW
MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS DURING
THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY HAS CONSEQUENTLY BEEN ISSUED FOR ALL BUT THE SOUTHERN
PIEDMONT...THOUGH THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN
THE ADVISORY GIVEN THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH
WINDS IMMEDIATELY BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
WINTER WEATHER POSSIBLE EARLY NEXT WEEK..
CONFIDENCE REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND
TUESDAY OF NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY
CONVERGENCE TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 130 AM SATURDAY...
CALM TO OCCASIONALLY LIGHT SOUTHERLY WINDS THIS MORNING WILL BECOME
SW TO SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW
BETWEEN MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 700 AM SATURDAY...
LIGHT SOUTH TO SOUTHWESTERLY WINDS THIS MORNING WILL BECOME SW TO
SSW AND STEADILY INCREASE AFTER 14Z...IN STRENGTHENING FLOW BETWEEN
MODIFIED ARCTIC HIGH PRESSURE ALONG AND OFFSHORE THE SE US
COAST...AND A POWERFUL ARCTIC COLD FRONT APPROACHING FROM THE
NORTHWEST. AN AREA OF ALTOCUMULUS WILL SWEEP EAST AND GRAZE MAINLY
THE NORTHERN HALF OF THE FORECAST AREA AROUND MIDDAY...AMIDST AN
OTHERWISE MOSTLY CLEAR SKY.
THE APPROACHING ARCTIC COLD FRONT WILL THEN BRING A FRIGID AND WINDY
BLAST OF AIR THROUGH CENTRAL NC THIS EVENING...AT WHICH TIME
NORTHWESTERLY WIND GUSTS OF 35 TO 45 MPH WILL BE COMMON...THE
STRONGEST OF WHICH WILL OCCUR WITHIN THE FIRST FEW HOURS OF FRONTAL
PASSAGE. A TEMPO GROUP HAS BEEN ADDED TO HIGHLIGHT THIS OCCURRENCE
AND TIMING AT THE RESPECTIVE TAF SITES. A FEW SHOWERS OR SPRINKLES
WILL ALSO ACCOMPANY THE FRONT...MOST LIKELY AT KRDU AND KRWI...THE
LATTER OF WHICH MAY EXPERIENCE A FEW WET SNOW FLAKES OR FLURRIES AS
WELL. WHILE THERE IS A SLIGHT CHANCE OF A BRIEF MVFR CEILING AND/OR
VISIBILITY RESTRICTION IN ASSOCIATION WITH ANY LOCALLY HEAVIER
PRECIPITATION...ODDS ARE THAT CONDITIONS WILL REMAIN VFR EVEN WHERE
PRECIPITATION BRIEFLY OCCURS.
OUTLOOK: WIDESPREAD SUB-VFR CONDITIONS AND PRECIPITATION...
INCLUDING SOME WINTRY...WILL BE POSSIBLE IN ASSOCIATION WITH A
COASTAL LOW MON NIGHT THROUGH TUE NIGHT...THOUGH FORECAST CONFIDENCE
REMAINS LOWER THAN AVERAGE.
&&
.FIRE WEATHER...
AS OF 700 AM SATURDAY
A BREEZY AND RELATIVELY MILD (TEMPS IN THE 50S) SOUTHWESTERLY WIND
WILL INCREASE INTO THE 15-20 KT RANGE...WITH GUSTS BETWEEN 25 AND 30
KTS - STRONGEST OVER THE SANDHILLS AND COASTAL PLAIN. IN
ADDITION...MINIMUM RELATIVE HUMIDITY VALUES WILL FALL TO AROUND 25
PERCENT...AS TEMPERATURES RISE INTO THE 50S...AND DRYNESS IN
ASSOCIATION WITH A LINGERING MODIFIED ARCTIC SURFACE RIDGE REMAINS.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THIE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE AGAIN
TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ028-042-043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...SMITH
AVIATION...RAH
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1007 AM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO AS LOW PRESSURE DEEPENS RAPIDLY JUST EAST
OF THE NEW ENGLAND COAST. THE NEXT CHANCE FOR ACCUMULATING SNOW
WILL ARRIVE TUESDAY AFTERNOON INTO WEDNESDAY AS AN AREA OF LOW
PRESSURE MOVES NORTHEAST FROM THE GULF COAST STATES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MESO ANAL INDICATES THE ARCTIC COLD FRONT IS DROPPING INTO NRN
OHIO AS OF MID MORNING. LOCALLY WE HAVE A WIDESPREAD AREA OF
FAIRLY LIGHT SNOW BEING FORCED BY STRONG WARM ADVECTION AHEAD OF
THE APPROACHING FRONT.
THE LACK OF DEEP MOISTURE WILL LIMIT THE LIGHT SNOW ACCUMS TO
MAINLY THE NORTHERN MOUNTAINS...WHERE OROGRAPHIC LIFT WILL PLAY A
ROLE.
HIGH RES MODELS INDICATE A LINE OF SNOW SQUALLS ENTERING THE NW
PORTIONS OF THE REGION AROUND MID DAY...PROGRESSING OFF TO THE
EAST THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT APPROACHING THE RT 219 CORRIDOR
IN WESTERN PA AROUND 19-20Z...RT 220/INTERSTATE 99 AROUND
21Z...AND THE MIDDLE AND LOWER SUSQ VALLEY 22-23Z TODAY.
WOULD NOT RULE OUT THUNDER SNOW AS THE DYNAMICS LOOK ESPECIALLY
ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
A WINT WX ADVISORY COVERS MUCH OF CENTRAL PA FROM THE MID MORNING
HOURS TODAY...THROUGH 12Z SUNDAY AS MDL BLENDED QPF COMBINED WITH
SLR/S OF CLOSE TO 20/1 SUPPORT A GENERAL 2-4 INCH SNOWFALL TODAY
AND TONIGHT FROM THE ONE-TWO PUNCH OF THE ARCTIC FRONT...THEN
PERIODS OF SNOW/SNOW SHOWERS ASSOCIATED WITH THE PASSAGE OF THE SE
DIGGING CLOSED UPPER LOW. THE HIGHER SNOWFALL AMOUNTS WILL BE
CONFINED TO MAINLY THE NW MTNS...WRN POCONOS AND ENDLESS MTNS OF
NEPA...AND THE LAUREL HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
AFTER EXTENSIVE COLLABORATION WITH SURROUNDING WFOS /WITH KLWX
HAVING SLIGHTLY LOWER CRITERIA FOR THRESHOLD VALUES FOR BOTH WIND
CHILLS AND SNOWFALL TO OUR SOUTH/...WE DECIDED TO NOT SPLIT HAIRS
WITH THE EXTREME COLD AND ISSUE A WIND CHILL WARNING FOR THE
ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY. HIGH
TEMPERATURES SUNDAY WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
ALTHOUGH WINDS WILL GRADUALLY RELAX INTO MON...COMBINATION OF
COLD TEMPS AND WIND JUSTIFIES THE WIND CHILL WATCH CURRENTLY IN
EFFECT THROUGH THAT 36HR PERIOD. THIS WILL LIKELY NEED TO BE
UPGRADED TO A WARNING AS EVENT WINDOW APPROACHES. WILL ALSO NEED
TO STRONGLY CONSIDER A WIND ADVISORY ESP FOR HIGHER TERRAIN AND
NW-SE ALIGNED VALLEYS ACROSS SOUTHERN AREAS SAT NIGHT INTO EARLY
SUN WITH PEAK WIND GUSTS IN THE 40-50 MPH RANGE.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS
CONTINUE TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER
SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT
LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM
PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
A SFC LOW LOCATED OVER SRN ONTARIO AT 12Z WILL TRACK ESE ACROSS
THE NRN MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY
INTENSIFYING JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY
SUNDAY.
AN ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE THE
FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WINDS
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH PEAK
GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR IN
OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON...VFR/NO SIG WX.
TUE...CHC OF IFR/SNOW SOUTHERN/EASTERN AIRSPACE.
WED...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ012-018-
019-025>028-037-041-042-045-046-049>053-058.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010-011-017-024-033.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/RXR
AVIATION...STEINBUGL/LA CORTE
Area Forecast Discussion
National Weather Service Spokane WA
535 AM PST SAT FEB 14 2015
.SYNOPSIS...
Warm temperatures will continue today while a weak cold front
passes through the region. The front could produce some light rain
most of which will fall over the southern portions of the Idaho
Panhandle. Dry conditions will move into the area behind the front
and seasonal temperatures will prevail Sunday and into early next
week.
&&
.DISCUSSION...
...updated todays forecast to issue dense fog for the Columbia
Basin and western portions of the Spokane area. Cold front
continues to exit the region with little if any echoes or
precipitation noted by radar. So not only has the cold front
failed to deliver precipitation it also did nothing to perturb the
stable and moist boundary layer. The latest satellite fog product
was showing widespread stratus across most of the Columbia
Basin...Palouse...northern valleys of Washington...and into the
north Idaho. While this wasn`t all fog...webcams were showing
fairly widespread dense fog across the Columbia Basin and into
western Spokane. Not confident this will burn off quickly and if
the HRRR is correct it could persist at least through midday. This
could potentially wreak havoc with this afternoons high
temperature forecast.
Today and Tonight...Main focus for todays weather will be the
passage of a weak cold front which is currently trudging through
the longwave upper level ridge. Satellite suggests the front is
shearing apart with time as the upper level moisture and
associated shortwave trough has shifted far ahead of the lower
level moisture. IR satellite was showing the upper and mid level
moisture has moved into SE Washington and the Idaho
Panhandle...while the lower-level portions of the frontal moisture
is being held at the Cascade Crest. This suggests the front could
have a tough time producing much precipitation today. Isentropic
analysis from the 06z NAM is showing this quite well and suggests
precipitation will be a non- factor today except for a chance of
very light rain over the Idaho Panhandle later this morning into
early afternoon as the low-level moisture receives a little
orograpic lift from westerly flow. Any precipitation which falls
will be well under a tenth of an inch.
Aside from the threat of precipitation, the big question is will
this front be able to rid the region of the stratus. Hopefully the
answer is yes as 850 mb temps cool anywhere from 4-7C vs yesterday
which should weaken low-level inversions markedly. However there
won`t be a big increase in boundary layer mixing potential with
fairly weak pressure gradients. That suggests the front could be
somewhat ineffective in getting rid of the fog and low clouds
which are currently covering much of the Columbia Basin...north
Idaho Panhandle...and likely beginning to extend into the Spokane
area. How quickly the low clouds and fog clear will have a direct
impact on afternoon high temperatures. Currently we are
forecasting high temps in the mid 40s over north Idaho...where the
fog may be most persistent to the mid to upper 50s near Wenatchee
where plenty of sunshine is expected. All locations will see the
trend of above normal temperatures with a few record highs
possible mainly over the western part of the forecast area.
For tonight...skies should generally clear over most the region
with much cooler overnight lows than we have seen for the past
week or so. Fog chances should be considerably less than we have
seen due to low level cold and dry advection. If we see fog the
best chances will be over the northern valleys where the inversion
forecast is strongest. fx
Sunday through Saturday: The amplified ridge off the west coast
will remain in place through Monday. Then Tuesday the ridge shifts
east over the Pac NW. Models start to diverge by Wednesday as to
whether a wave will move over the ridge. Each model run seems to
have a different solution as to what to do with the ridge.
Experience tells me that the ridge is so strong that the models
are breaking the ridge down too easily. So, for now have lowered
our chance of precipitation across southeast WA and north ID
through the extended period. Have kept our chance of precipitation
along the crest of the Cascades Thursday night onward. The ridge
axis will be far enough east to allow sufficient moisture to move
in for some showers right along the crest. Temperatures do lower
as compared to what we saw earlier this week, but daytime
temperatures still look to be 5-10 degrees above average for this
time of the year. Min temperatures will be a bit more tricky with
mostly clear skies and opportunities for locations to radiate out
after sunset. Even so, with no decent arctic air moving in from
the north and the flow switching to southwesterly by Tuesday lows
will be at or slightly above average for this time of the year.
/Nisbet
&&
.AVIATION...
12Z TAFS: Widespread stratus has developed across much of of
eastern Washington and the Idaho Panhandle north of Pullman. This
blanket of low clouds will likely persist through 18-20z or so and
LIFR conditions expected from dense fog. This will impact
PUW...GEG...and MWH. SFF and COE will also see stratus with slowly
lowering cigs...but these will likely remain IFR. Hopefully the
fog will burn off by 20z...but this is a very expansive blanket of
clouds and the passing cold front did little to break it up. Its
quite possible the low clouds could persist into the late
afternoon hours for GEG SFF PUW and COE. MWH has a better chance
of breaking up since its on the western edge of the cloud blanket.
If fog does break up today...there is a small chance of it
reforming late in the forecast period...after 06z or so. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 51 32 48 28 48 30 / 10 0 0 0 0 0
Coeur d`Alene 50 30 47 27 47 28 / 20 0 10 0 0 0
Pullman 52 35 49 31 49 31 / 10 0 0 0 0 0
Lewiston 58 38 55 33 53 33 / 10 0 0 0 0 0
Colville 51 31 47 27 47 29 / 10 0 0 0 0 0
Sandpoint 45 31 42 25 42 25 / 30 0 10 10 0 0
Kellogg 46 33 43 27 43 27 / 30 10 10 10 0 0
Moses Lake 57 33 53 33 52 32 / 0 0 0 0 0 0
Wenatchee 57 35 51 33 50 33 / 0 0 0 0 0 0
Omak 53 30 49 30 49 31 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Dense fog advisory until 12 PM PST WAZ034-035-036
&&
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1202 PM CST SAT FEB 14 2015
.SHORT TERM...
332 AM CST
THROUGH SUNDAY...
NO CHANGES TO GOING HEADLINES FOR TODAY. HOWEVER...WE HAVE ISSUED A
WIND CHILL ADVISORY FOR THE AREA FOR TONIGHT.
MAIN WEATHER FORECAST CONCERNS CONTINUE TO FOCUS ON THE STRONG
ARCTIC PUSH TODAY...WITH DANGEROUS WIND CHILLS TONIGHT...AND ALSO
THE LAKE EFFECT SNOW SHOWERS...PARTICULARLY ACROSS NORTHWESTERN
INDIANA LATER TODAY AND TONIGHT...THEN OVER NORTHEASTERN ILLINOIS ON
SUNDAY.
WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS THE MAIN UPPER LEVEL PV
ANOMALY RAPIDLY DIGGING SOUTHWARD OVER NORTHERN WISCONSIN.
MEANWHILE...THE ASSOCIATED SURFACE LOW CONTINUES TO DEEPEN TO NEAR
1000 MB OVER THE UPPER GREAT LAKES REGION...WITH THE MAIN SURFACE
COLD FRONT RIGHT ON OUR DOOR STEP ACROSS FAR NORTHERN ILLINOIS.
TEMPERATURES AHEAD OF THIS FRONT AT STILL QUITE MILD IN THE UPPER
20S TO NEAR 30. HOWEVER...THE BOTTOM WILL FALL OUT IN A HURRY HERE
OVER THE NEXT FEW HOURS...AS TEMPERATURES QUICKLY TUMBLE INTO THE
TEENS AFTER DAYBREAK TODAY...AND CONTINUE TO FALL INTO THE SINGLE
DIGITS THIS AFTERNOON.
LOWER LEVEL LAPS RATES WILL STEEP UP FOLLOWING THE FRONTAL
PASSAGE...AND THIS SHOULD ALLOW FOR THE DEVELOPMENT OF SOME ISOLATED
TO SCATTERED SNOW SHOWERS ACROSS THE REGION THIS MORNING.
HOWEVER...IT APPEARS THE BETTER FOCUS FOR SNOW SHOWERS...OUTSIDE OF
LAKE EFFECT...WILL OCCUR ACROSS MY SOUTHERN AREAS THIS MORNING AS THE
LOWER LEVEL BAROCLINIC ZONE CONTINUES TO STRENGTHEN...SETTING UP A
BAND OF STRONG FGEN ACROSS CENTRAL ILLINOIS THIS MORNING. THIS WILL
BE A SHORT LIVED FEATURE...HOWEVER...SO SNOW AMOUNTS AREA-WIDE WILL
LIKELY REMAIN A HALF IN OR LESS.
NORTHERLY WINDS WILL INCREASE QUICKLY THIS MORNING...AND THE
COMBINATION OF VERY STRONG COLD AIR ADVECTION...AND RAPID PRESSURE
RISES...COULD RESULT IN A PERIOD OF NEAR WIND ADVISORY CRITERIA WINDS
(GUSTS TO 45 MPH)...PARTICULARLY ACROSS EASTERN ILLINOIS AND
NORTHWESTERN INDIANA LATER THIS MORNING AND INTO THE AFTERNOON.
MODEL SOUNDINGS ACROSS THESE AREAS INDICATE MEAN MIXING LAYER WINDS
AROUND 36 KT...WITH AROUND 40 TO 42 KT AT THE TOP OF MIXING LAYER.
STRONGLY FORCED COLD AIR ADVECTION REGIMES SUCH AS WHAT IS EXPECTED
THIS MORNING...CAN SET UP SITUATIONS WHEN SOME OF THE HIGHEST WINDS
IN THE MIXING LAYER MIX DOWN TO THE SURFACE AS WIND GUSTS...AT LEAST
FOR SHORT PERIODS OF TIME. IF THIS DOES OCCUR...THERE COULD BE A
SHORT PERIOD WITH WIND GUSTS TOPPING 45 MPH TODAY. OVERALL IT
APPEARS THE STRONGEST WIND POTENTIAL WILL BE NEAR THE LAKE IN
NORTHWESTERN INDIANA...AND THIS AREA IS CURRENTLY COVERED BY EITHER
A WIND ADVISORY OR A WINTER STORM WARNING. WE THOUGHT ABOUT POSSIBLY
EXPANDING THE WIND ADVISORY TO INCLUDE ALL OF NORTHWESTERN INDIANA
AND SOME OF EASTERN ILLINOIS. HOWEVER...AFTER COLLABORATING WITH
NEIGHBORING OFFICES...WE HAVE DECIDED NOT TO EXPAND THE CURRENT WIND
ADVISORY.
THE LAKE EFFECT POTENTIAL IS REALLY UNCHANGED FROM PREVIOUS
FORECASTS. IT STILL APPEARS THAT THE MAIN SETUP TODAY WILL FAVOR
NORTHEASTERN PORTER COUNTY INDIANA AND POINTS EAST...AS STRONG
NORTHWESTERN BOUNDARY LAYER WINDS KEEP THE BETTER LOWER LEVEL
CONVERGENCE MORE BROAD...AND MAINLY TO THE EAST OF MY AREA. THIS
COULD SUPPORT MULTIPLE BANDS OF LAKE EFFECT SNOW SHOWERS. HOWEVER...IT
STILL DOES APPEAR THAT AS A STOUT SURFACE BUILDS EASTWARD ACROSS THE
UPPER MIDWEST BY THIS EVENING...THAT THE BOUNDARY LAYER WINDS OVER
LAKE MICHIGAN WILL BECOME MORE NORTHERLY...AND GRADUALLY EASE IN
MAGNITUDE OVERNIGHT TONIGHT. THIS COULD SET UP MORE OF A SINGLE
CONVERGENT WESTWARD MOVING BAND OF LAKE EFFECT SNOW SHOWERS OVER
SOUTHERN LAKE MICHIGAN TONIGHT...AND BETTER ACCUMULATION POTENTIAL
FOR MY NORTHWESTERN INDIANA COUNTIES NEAR THE LAKE. INVERSION
HEIGHTS SHOULD BE ON A DECLINE DURING THIS TIME. HOWEVER...GIVEN THE
COLD AIRMASS...THE CLOUDS SHOULD BE COLD ENOUGH TO SUPPORT ICE
CRYSTALS. TOTAL SNOWFALL AMOUNTS SHOULD NOT GET TO OUT OF HAND...AS
THE BAND SHOULD BECOME PROGRESSIVE. HOWEVER...AMOUNTS IN EXCESS OF 6
INCHES ARE STILL POSSIBLE ACROSS PORTIONS OF THE WARNING AREA.
ADDITIONALLY...WITH THE STRONG WINDS TODAY AND THIS EVENING...BLOWING
SNOW AND WHITE OUT CONDITIONS WILL BE A CONCERN AT TIMES.
WINDS OVER THE LAKE WILL CONTINUE TO BACK MORE NORTHEASTERLY FOR A
PERIOD ON SUNDAY...SO SOME LIGHT LAKE EFFECT SNOW SHOWERS APPEAR
LIKELY ACROSS THE CHICAGO AREA OF NORTHEASTERN ILLINOIS.
HOWEVER...THE BAND OF SNOW SHOWERS LOOKS TO BECOME A LESS ORGANIZED
BY SUNDAY. THEREFORE...IT STILL APPEARS THAT ACCUMULATIONS ACROSS
THE CHICAGO AREA WILL GENERALLY REMAIN ON THE LIGHT SIDE. THE WINDS
ARE EXPECTED SHIFT OFFSHORE BY EARLY SUNDAY EVENING...SO ANY
LINGERING SHOWERS WILL END BY THIS TIME.
A WIND CHILL ADVISORY WILL GO INTO EFFECT FOR THE REGION THIS
EVENING. THE COMBINATION OF LINGERING BREEZY WINDS AND TEMPERATURES
FALLING INTO NEGATIVE TERRITORY THROUGH THE EVENING WILL SET UP WIND
CHILLS OF 20 BELOW TO 30 BELOW...WITH THE COLDEST EXPECTED ACROSS
NORTH CENTRAL ILLINOIS. THIS ADVISORY WILL BE IN EFFECT UNTIL MID
MORNING ON SUNDAY. TEMPERATURES LOOK TO ONLY TOP OUT NEAR 10 ABOVE IN
MOST AREAS ON SUNDAY...BUT WITH LIGHT WINDS DURING THE DAY...WIND
CHILLS SHOULD NOT BE AN ISSUE.
KJB
&&
.LONG TERM...
332 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
THE WEATHER PATTERN OVER THE COUNTRY WILL CONTINUE TO FAVOR
PERIODS OF COLD ARCTIC OUTBREAKS OVER THE EASTERN HALF OF THE
CONUS NEXT WEEK. STRONG HIGH LATITUDE UPPER RIDGING OVER THE EASTERN
PACIFIC/WESTERN NORTH AMERICA WILL SET THE STAGE FOR A FAIRLY
PROLONGED PERIOD OF MUCH BELOW NORMAL HEIGHTS AND TEMPERATURES
ACROSS MUCH OF EASTERN NORTH AMERICA. OUTSIDE OF LAKE EFFECT
SNOWS...NO BIG SNOW EVENTS ARE EXPECTED THROUGH THE PERIOD.
HOWEVER...SOME MINOR SNOW SYSTEMS COULD IMPACT THE AREA WITHIN THE
CYCLONIC UPPER LEVEL FLOW PATTERN. A REINFORCING SHOT OF COLD
ARCTIC AIR LOOKS TO SET UP OVER THE AREA BY MID WEEK...AND THIS
AIRMASS COULD EVEN BE A BIT COLDER THAN THE SHORT TERM COLD
EXPECTED. THIS COULD RESULT IN HIGH TEMPERATURES ONLY IN THE
SINGLE DIGITS IN MOST AREAS ON WEDNESDAY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NORTHWEST TO NORTH-NORTHWEST WINDS GUSTING TO AROUND 35 KT
THROUGH EARLY AFTERNOON...DIMINISHING THROUGH THE EVENING AND
OVERNIGHT.
* SCATTERED SNOW SHOWERS THROUGH EARLY AFTERNOON...OCNL MVFR
CIG/VIS POSSIBLE.
* VARIABLE MVFR TO VFR CIGS...IMPROVING TO PREVAILING VFR THIS
AFTERNOON.
* SNOW CHANCES ONCE AGAIN SUNDAY WITH MVFR CIGS AND IFR VSBY
POSSIBLE.
KREIN
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT HAS PUSHED SOUTH INTO THE OHIO VALLEY WITH
STRONG HIGH PRESSURE BUILDING OVER THE NRN PLAINS AND UPPER
MISSISSIPPI VALLEY. ALSO LOW PRESSURE ASSOCIATED WITH THE COLD
FRONT IS MOVING THROUGH THE EASTERN GREAT LAKES. THE HIGH IS
ASSOCIATED WITH A VERY COLD AIRMASS AND WITH THE CENTER OF THE
HIGH STILL OVER MANITOBA...A STRONG NORTHWESTERLY PRESSURE
GRADIENT HAS SET UP ACROSS THE REGION. THE COMBINATION OF THE
STRONG GRADIENT AND STRONG COLD ADVECTION HAS BROUGHT STRONG WIND
GUSTS OF 35-40KT ACROSS NRN IL/IN. A STRONG UPPER LEVEL IMPULSE
AND A JET STREAK CROSSING CENTRAL IL/IN HAVE HELP FOCUS THE
DEVELOPMENT OF BANDS OF SNOW SHOWERS ACROSS THE REGION...WITH
OCCASIONAL BURSTS OF IFR VIS AND LOWER END MVFR CIGS. THROUGH THE
AFTERNOON...EXPECT A DOWNWARD TRENDS IN WINDS SPEEDS AND GUSTS
WHILE DIRECTION REMAINS GENERALLY NNWLY. THE COVERAGE OF SNOW
SHOWERS SHOULD ALSO DIMINISH WITH TIME THROUGH THE AFTERNOON AS
DRIER AIR FILTERS ACROSS THE REGION...BUT RESIDUAL STRONG WINDS
SHOULD CONTINUE TO GENERATE AREAS OF BLOWING SNOW WHICH MAY REDUCE
VIS TO 3-5SM. AS THE CENTER OF THE HIGH BUILDS ACROSS THE UPPER
GREAT LAKES TONIGHT...WITH A RIDGE AXIS EXTENDING SOUTH AND
TRACKING MISSISSIPPI VALLEY...WINDS SHOULD DIMINISH TO LESS THAN
10KT BY EARLY TOMORROW MORNING. AS THE RIDGE AXIS ACROSS LAKE
MICHIGAN TOMORROW MORNING...EXPECT A PLUME OF LAKE EFFECT SNOW TO
DEVELOP OVER SOUTHERN LAKE MICHIGAN...WHICH THE HIGH RES MODEL
GUIDANCE CONSISTENTLY SUGGESTING SHOULD MOVE WEST INTO NERN
IL...POSSIBLY AFFECTING GYY/ORD/MDW. SHOULD THE LAKE EFFECT PLUME
MOVE INLAND FAR ENOUGH...IFR CONDITIONS WILL BE LIKELY AT THESE
TERMINALS. AT THIS POINT...DO NOT EXPECT THE LAKE EFFECT SNOW TO
MOVE FAR ENOUGH WEST TO IMPACT DPA AND RFD SHOULD BE WELL REMOVED
FROM ANY LAKE INFLUENCE AND CONDITIONS SHOULD BE VFR WITH LIGHT
WINDS THROUGH THE DAY. OTHER THAN THE CHANCES FOR LAKE EFFECT SNOW
SHOWERS TOMORROW MORNING...CONDITIONS SHOULD BE QUIET AT THE
EASTERN TERMINALS BY TOMORROW AFTERNOON WITH LIGHT SELY WINDS AND
UNRESTRICTED CIG/VIS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TRENDS.
* HIGH CONFIDENCE IN SCATTERED SNOW SHOWERS THROUGH EARLY THIS
AFTERNOON. LOW CONFIDENCE IN ANY IMPACTS AT THE TERMINALS AS
ACTIVITY IS ON A DIMINISHING TREND.
* HIGH CONFIDENCE IN GENERAL CIG/VIS TREND...LOWER CONFIDENCE IN
THE DURATION OF ANY REDUCED CIG/VIS EARLY THIS AFTERNOON AND
TOMORROW MORNING DUE TO RESIDUAL SNOW SHOWERS THIS AFTERNOON AND
LAKE EFFECT SNOW SHOWERS TOMORROW MORNING.
* HIGH CONFIDENCE IN SNOW FORECAST FOR SUNDAY...BUT ONLY MEDIUM
CONFIDENCE IN TIMING AND DURATION.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY...MVFR. SLIGHT CHANCE OF SNOW. SOUTHWEST WINDS.
TUESDAY THROUGH THURSDAY...PERIODS OF MVFR POSSIBLE. WEST TO
NORTHWEST WINDS.
FRIDAY...VFR. SOUTHWEST WINDS.
MDB
&&
.MARINE...
317 AM CST
LOW PRESSURE JUST EAST OF LAKE SUPERIOR OR OVER NORTHERN GEORGIAN
BAY WILL MOVE SOUTHEAST TO THE SOUTHERN NEW ENGLAND COAST INTO
TONIGHT WHILE STRENGTHENING. VERY STRONG HIGH PRESSURE OVER THE
CANADIAN PRAIRIES WILL SETTLE SOUTHWARD INTO THE MID AND UPPER
MISSISSIPPI RIVER VALLEY AND WESTERN GREAT LAKES INTO SUNDAY.
WINDS ARE SHIFTING FROM SOUTHWEST TO NORTHWEST AS A STRONG COLD
FRONT PUSHES SOUTHWARD DOWN THE LAKE THIS MORNING. WITH THE LOW
DEEPENING AND THE VERY STRONG HIGH ALLOWING FOR AN INCREASING
PRESSURE GRADIENT AND THEN COMBINING WITH THE STRONG COLD
ADVECTION BEHIND THE FRONT...WINDS WILL QUICKLY RAMP UP EARLY THIS
MORNING. PEAK WINDS ARE EXPECTED FROM MID/LATE MORNING THROUGH THE
AFTERNOON BEFORE SLOWLY EASING. 50 KT GUSTS LOOK LIKELY ACROSS
MUCH OF THE LAKE...ESPECIALLY THE SOUTHERN TWO-THIRDS...FROM LATE
MORNING THROUGH THE AFTERNOON. WITH ROUGHLY 6 HOURS OF GALES
EXPECTED PRIOR TO THE STORM FORCE WINDS...HAVE OPTED TO KEEP A
GALE WARNING IN EFFECT OUT THE GATE UNTIL A STORM WARNING TAKES
OVER AT 15Z FOR THE OPEN WATERS. HAVE THEN KEPT THE EXISTING GALE
WARNING FROM MID EVENING INTO THE OVERNIGHT. WILL KEEP NEARSHORE
AREAS IN A GALE...WITH STORM FORCE WINDS MORE LIKELY TO THE
EAST...BUT WILL MENTION POSSIBLE STORM FORCE GUSTS FOR THE INDIANA
WATERS. BETWEEN THE WINDS AND WAVES HEAVY FREEZING SPRAY WILL
OCCUR AND HAVE MAINTAINED THE HEAVY FREEZING SPRAY WARNING.
THE HIGH MOVES ACROSS THE GREAT LAKES SUNDAY THROUGH MONDAY WHICH
WILL LEAD TO WINDS WHICH WILL TURN EASTERLY SUNDAY AND SUNDAY NIGHT
BEFORE SOUTHWEST WINDS TAKE OVER AHEAD OF THE NEXT SERIES OF LOW
PRESSURE SYSTEMS. THIS WILL MEAN ANOTHER PERIOD OF NORTHERLY WINDS
AS WELL AS VERY COLD TEMPERATURES BY WEDNESDAY. HIGH PRESSURE IS
THEN EXPECTED TO RETURN LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...8 PM SATURDAY TO 9 AM SUNDAY.
IN...WIND ADVISORY...INZ001 UNTIL 6 PM SATURDAY.
WIND CHILL ADVISORY...INZ001-INZ010-INZ011-INZ019...8 PM
SATURDAY TO 9 AM SUNDAY.
WINTER STORM WARNING...INZ002 UNTIL 9 AM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM SATURDAY TO 3 AM
SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SUNDAY.
STORM WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SATURDAY.
GALE WARNING...NEARSHORE WATERS UNTIL 3
AM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1200 PM CST Sat Feb 14 2015
.UPDATE...
ISSUED AT 1049 AM CST SAT FEB 14 2015
Cold front has quickly dropped southward into the Ohio River
Valley this morning, taking much of the snow with it. 16z/10am
radar mosaic shows light snow lingering across the SE KILX CWA,
mainly along/south of an Effingham to Robinson line. The snow will
persist for another 1 to 2 hours, then will exit the area by
midday, leaving behind accumulations between one half and one inch.
Further north, clearing line is already working its way into
north-central Illinois and will rapidly sweep southward this
afternoon. Meanwhile, quite a bit of diurnal Cu has developed
across the Great Lakes into northern Illinois and will brush the
N/NE CWA through mid-afternoon before gradually dissipating later
in the day. May even see a few flurries, especially along/northeast
of a Lacon to Paris line. Big story today will be the windy and
sharply colder conditions. Latest obs show winds gusting to
between 35 and 40mph across the board. Greatest 3-hr pressure
rises of around 10mb are currently analyzed across Iowa into
Wisconsin and these are progged to slide southeastward into the
area early this afternoon. May see a few gusts of 40-45mph at
times, but will generally stay near or just below Wind Advisory
criteria. Temps have already reached daily maxes and are on their
way down, with readings expected to range from the single digits
north to around 20 degrees far south by late afternoon.
&&
.SHORT TERM...(Today)
ISSUED AT 330 AM CST SAT FEB 14 2015
The Arctic cold front has reached southeastern Iowa and it should
reach near the Illinois river around sunrise, then progress across
the remainder of our counties this morning. The 00z models continue
to show a band of snow showers along and behind the front, with the
higher accumulations concentrating on the southwestern half of our
forecast area this morning. The upstream radar and satellite images
seem to be correlating well with the RAP area of 700-850mb
frontogenetic forcing. The forecast soundings still show limited
deep layer moisture, with disjointed saturated layers during the
morning. Dry air will likely limit the snowfall potential of the
system, but narrow bands of enhanced lift could linger in localized
areas as the mid-level forcing advances across C IL. Isolated bands
of up to 1 inch can not be ruled out in those cases, but most areas
should stay below a half inch, with some areas just seeing trace
amounts. Pinpointing exact locations of the bands is difficult even
this close to the event, and ongoing evaluation of correlating RAP
F-gen with radar and satellite will be needed through the morning to
keep any localized bands of heavier snow covered in the gridded
forecast.
Have advanced a band of likely PoPs this morning across our
southwest areas, but also included an hour or two of likely PoPs as
far north as Lincoln to Paris. Chance PoPs were included for at
least a couple hours in all of our northern counties at some point
this morning when the F-gen and moisture best coincide.
Temps will be steady or falling through the day. High temps for this
calendar day most likely will occur early this morning ahead of the
cold front. Strong pressure rises this afternoon will cause blustery
northwest winds to develop, with sustained speeds of 20-30 mph and a
few gusts around 40 mph. Wind chills by late afternoon will dip
below zero across all of our area, with -10 to -15F north of Peoria
already by 00z/6pm.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 330 AM CST SAT FEB 14 2015
Vigorous short wave to track into the mid Atlantic states this
evening and deepen a very strong surface low off the New England
coast tonight. This to bring yet another blizzard to coastal New
England including Boston tonight into Sunday. But for IL the main
story will be the bitter cold temperatures and wind chills. Will
issue a wind chill advisory tonight starting at 6 pm and go until 9
am Sunday for areas from Canton to Lincoln to Terre Haute northeast
where wind chills get down to 15-20 below zero. Lows overnight range
from zero to 5 below from Lincoln and Champaign north to 0 to 5
above south from I-72 south.
Strong 1046 mb arctic high pressure over nw Manitoba to weaken to
1035 mb as it drifts into the Great Lakes region Sunday afternoon.
Meanwhile a weak northern stream short wave will dive se from the
Pacific Northwest into the MO valley Sunday evening and bring chance
of light snow and flurries to areas sw of Lincoln later Sunday
afternoon into Sunday night. Snow accumulations of a dusting to up
to a half inch sw third of CWA possible with better chances of light
snow accumulations over sw and southern IL. Cold highs Sunday in the
teens. Lows Sunday night around 5F from I-74 ne to around 10F sw
CWA.
Dry conditions prevail Monday and Monday night with surface ridge
over IL with partly to mostly cloudy skies. Highs in mid to upper
20s which is still 10-15 degrees below normal for mid February.
00Z models continue to keep a stronger southern stream wx system
south of central IL Tue with surface low over southern MS river
valley. Have just chance of flurries far sw/southern counties on
Tue. Another surge of arctic air arrives Tue night through Wed night
with wind chills reaching near or a bit colder than 15 below over
northern counties. Dry conditions prevail rest of the week as temps
modify into low to mid 30s Friday afternoon.
The Climate Prediction Center (CPC) Day 8-14 Temperature Outlook for
Feb 21-27th has IL in a greater than 80% chance of below normal
temperatures, and this covers the Great Lakes region including IN/OH.
So winter`s grip looks to continue across the region the rest of the
month as upper level trof generally prevails over eastern North America
east of the Rockies.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1200 PM CST SAT FEB 14 2015
Strong northwesterly winds gusting to between 25 and 35kt will
persist through mid-afternoon before slowly beginning to diminish
by this evening. Pressure gradient will remain tight enough to
support continued gusts to around 20kt at the eastern terminals
through around 04-05z, before winds subside to 12kt or less
overnight. Diurnal cloud cover associated with a vigorous
upper-level disturbance over the Great Lakes will skirt across the
N/NE KILX CWA this afternoon. VFR ceilings of around 3500ft can be
expected at times for the I-74 TAF sites, with mostly clear skies
further southwest at both KSPI and KDEC. Once these clouds
dissipate later this afternoon, mostly clear conditions will
prevail until mid-level clouds begin to increase from the west
after 09z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 6 PM this evening to 9 AM CST Sunday
FOR ILZ027>031-036>038-041>046-055-057.
&&
$$
UPDATE...Barnes
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS GOODLAND KS
400 PM MST SAT FEB 14 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 153 PM MST SAT FEB 14 2015
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 499 DM UPPER LOW
CENTERED OVER THE EASTERN GREAT LAKES REGION. NW FLOW IS IN PLACE
ACROSS THE PLAINS, WITH A SHORTWAVE TROUGH MOVING INTO THE
NORTHERN PLAINS FROM CANADA. AT THE SURFACE A COLD FRONT IS IN THE
PROCESS OF MOVING ACROSS OUR CWA...AND IS CURRENTLY WEST OF KGLD
NEAR THE COLORADO BORDER...EXTENDING SOUTH JUST EAST OF KDDC.
THIS FRONT WILL CONTINUE TO TRANSITION WESTWARD THROUGH THE LATE
AFTERNOON AND EVENING...BEFORE STALLING IN EASTERN COLORADO (WEST
OF OUR CWA). CAA WILL CONTINUE THROUGH THE OVERNIGHT PERIOD WITH
MUCH COLDER TEMPS CONTINUING THROUGH THE DAY SUNDAY. THERE MAY BE
A PERIOD OF RETURN FLOW AND CLEARING IN SKY COVER FROM THE
SOUTHWEST...WHERE HIGHS SUNDAY MAY WARM INTO THE 40S. LOW-MID
CLOUDS MAY HOLD ON ACROSS THE EAST WHERE TEMPS MAY STRUGGLE TO
WARM ABOVE FREEZING SUNDAY AFTERNOON. NAM/SREF/RAP/HRRR CONTINUE
TO SHOW BL MOISTURE POOLING ALONG FRONTAL ZONE IN EASTERN COLORADO
WHICH COULD SUPPORT ADDITIONAL STRATUS OR FOG DEVELOPMENT. WE MAY
BE WELL MIXED ENOUGH THAT SIGNIFICANT VIS RESTRICTIONS WOULD NOT
BE AN ISSUE...AND GUIDANCE CURRENTLY KEEPS VIS ABOVE 3SM. I LEFT
PATCHY FREEZING FOG MENTION IN THE WEST...BUT NOT A LOT OF
CONFIDENCE.
SHORTWAVE TROUGH MOVES OVER THE REGION WITH SECOND ROUND OF CAA
ARRIVING BY LATE AFTERNOON. MAIN AREA OF FORCING WILL BE ASSOCIATE
WITH LOBE OF VORTICITY/ELEVATED BAROCLINIC ZONE WHICH CURRENT
TIMING FAVORS LATE AFTERNOON IN THE NORTH. MADE ADJUSTMENTS TO
BLEND WITH EVENING PERIOD AND SHOW THIS TRANSITION. ANY PRECIP IN
THE AFTERNOON WILL LIKELY BE MORE OF A RAIN/SNOW MIX BASED ON TEMP
PROFILES/WBZ HEIGHTS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 159 PM MST SAT FEB 14 2015
FOR THE EXTENDED PERIOD...THE H5 RIDGE WHICH HAD BEEN OVER THE
WESTERN HALF OF THE COUNTRY OVER THE PAST SEVERAL DAYS...WILL NOW
SHIFT FURTHER WEST FOR THE UPCOMING WEEK...MAINLY SETTING UP ALONG
THE WEST COAST. THIS IN TURN WILL ALLOW A BROAD...DEEP H5 LOW TO
ENCOMPASS ALMOST 2/3RDS OF THE COUNTRY. DURING THE COURSE OF THE
UPCOMING WEEK...THE TRI STATE REGION WILL SEE A COUPLE OF SHORTWAVES
MOVING ALONG THE BASE OF THE UPPER LOW...GIVING THE CWA A CHANCE FOR
SOME NEEDED PRECIPITATION.
FIRST SYSTEM WILL MOVE SOUTH THRU THE ROCKIES LATE SUNDAY NIGHT INTO
MONDAY NIGHT...FOLLOWED BY A WEAKER SECONDARY SYSTEM ON TUESDAY. A
STRONG SURFACE RIDGE WILL ACCOMPANY THE FIRST SHORTWAVE...EDGING
DOWN THE EAST SIDE OF THE ROCKIES IN TANDEM WITH THE SHORTWAVE. THIS
IS GOING TO PUT AN EASTERLY FETCH ACROSS THE AREA...WITH SOME
UPSLOPE POTENTIAL FOR WESTERN ZONES AS SYSTEM SLIDES THRU THE AREA.
WILL BE CONTINUING AS A RESULT THE SNOWFALL GRADIENT FROM PREVIOUS
FORECAST...WITH HIGHEST POTENTIAL OVER WESTERN ZONES...ESPECIALLY
FOR EASTERN COLORADO. MODEL DIFFERENCE IN AMT OF QPF POTENTIAL FOR
THIS SYSTEM. THINKING UPSLOPE/OROGRAPHIC EFFECTS WILL HAVE BEST
CHANCE FOR SNOW ACCUM IN AFOREMENTIONED AREAS AT 1-2" WITH 0.5-1"
FOR EASTERN ZONES. SECOND SHORTWAVE PASSES THRU CENTRAL KANSAS ON
TUESDAY WITH EASTERN ZONES IN CWA GETTING CLIPPED AS IT SWINGS THRU.
WILL GO WITH A SLIGHT CHANCE FOR -RW/-SW...WITH LITTLE TO NO ACCUM
EXPECTED.
DRY CONDITIONS EXPECTED TUESDAY NIGHT THRU THURSDAY NIGHT WITH HIGH
PRESSURE MAIN WEATHER FEATURE OVER THE CENTRAL PLAINS...AND LEE-SIDE
TROUGH FORMATION OVER THE EASTERN SIDE OF THE ROCKIES. GOING INTO
FRIDAY AND NEXT SATURDAY...GFS/ECMWF DO DIFFER ON TIMING(AS MUCH AS
12 HRS) OF NEXT SHORTWAVE TO DIG SOUTH THRU THE ROCKIES AND ACROSS
THE CENTRAL PLAINS. CONSENSUS IS TO KEEP SLIGHT CHANCE POPS IN FOR
NOW. TEMPS ARE WARM ENOUGH DURING THE DAYTIME HOURS TO SUPPORT RW
MIXING IN WITH -SW...BUT -SW AT NIGHT.
TEMPERATURES IN THE EXTENDED WILL NEAR NORMAL NUMBERS EARLY IN THE
FORECAST WITH THE ARRIVAL OF CAA WITH MONDAY SHORTWAVE...THEN
INCREASING TO ABOVE NORMAL AS RIDGE SETS UP TO EAST THRU
MIDWEEK...THEN BACK DOWN TO NEAR NORMAL BY END OF WEEK WITH ARRIVAL
OF NEXT SHORTWAVE. OVERALL HIGHS WILL MAINLY IN THE 40S WITH 50S
POSSIBLE FRIDAY...AND OVERNIGHT LOWS WILL MAINLY RANGE IN THE TEENS
WITH SOME L20S BY END OF WEEK TIMEFRAME. SOME WIND GUSTS COULD REACH
INTO THE 15-25MPH RANGE WITH GRADIENT BEHIND EACH SUBSEQUENT
SHORTWAVE PASSAGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 400 PM MST SAT FEB 14 2015
KGLD...STRATUS AND MVFR CIGS PER SATELLITE IMAGERY AND RUC
950-925MB RH IS FORECAST TO BE JUST EAST OF THE TERMINAL AT TAF
ISSUANCE THEN MOVING WEST ACROSS THE TERMINAL IN THE 00Z-04Z
TIMEFRAME BRINGING MVFR CIGS WITH WINDS FROM THE EAST-SOUTHEAST
GUSTING 20-25KTS. IN THE 05Z- 06Z PERIOD BEST MOISTURE IN THIS
LAYER OVER FAR EASTERN COLORADO AND VFR CONDITIONS SHOULD RETURN
WITH SOUTHEAST WINDS JUST UNDER 12KTS. THESE WINDS ARE EXPECTED TO
CONTINUE THROUGH 15Z WITH PERHAPS SOME SCATTERED CLOUDS IN THE
MVFR CATEGORY BUT MOSTLY IN THE MID CLOUD CATEGORY. AROUND 16Z
WINDS SHIFT TO THE NORTH UNDER 10KTS INCREASING A BIT TOWARD 12KTS
FROM THE NORTHEAST IN THE 20Z-22Z TIMEFRAME BEFORE FALLING BELOW
10KTS BY 23Z. STILL CANT RULE OUT MVFR CIGS PER MODEL RH CROSS-
SECTIONS BUT FOR NOW WILL KEEP THOSE CLOUDS VFR WITH CIGS LOWERING
TOWARD 5K FT AT THE END OF THE PERIOD. NO PRECIPITATION CURRENTLY
EXPECTED. WILL HAVE TO MONITOR FOR FOG THREAT IN THE 06Z-15Z
TIMEFRAME AS WELL.
KMCK...STRATUS AND MVFR CIGS PER SATELLITE IMAGERY CURRENTLY OVER
THE TERMINAL AND RUC 950-850MB RH IS FORECAST TO SLOWLY MOVE WEST
AND AWAY FROM THE TERMINAL WITHIN THE NEXT HOUR OR TWO WITH WINDS
FROM THE EAST AROUND 13KTS. AROUND 06Z WINDS FALL BELOW 12KTS FROM
THE SOUTHEAST WITH SCATTERED CLOUDS IN MVFR CATEGORY AND A DECK
AROUND 15K FT. WINDS VEER TO THE SOUTH AND DECREASE TOWARD 5KTS
AROUND 15Z WITH CIGS LOWERING BUT REMAINING VFR. WIND SHIFT MOVES
THROUGH AROUND 21Z WITH NORTHWEST WINDS UNDER 10KTS THEN NORTHEAST
AT SIMILAR SPEEDS AROUND 23Z. NO PRECIPITATION CURRENTLY EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JN
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
159 PM MST SAT FEB 14 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 153 PM MST SAT FEB 14 2015
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 499 DM UPPER LOW
CENTERED OVER THE EASTERN GREAT LAKES REGION. NW FLOW IS IN PLACE
ACROSS THE PLAINS, WITH A SHORTWAVE TROUGH MOVING INTO THE
NORTHERN PLAINS FROM CANADA. AT THE SURFACE A COLD FRONT IS IN THE
PROCESS OF MOVING ACROSS OUR CWA...AND IS CURRENTLY WEST OF KGLD
NEAR THE COLORADO BORDER...EXTENDING SOUTH JUST EAST OF KDDC.
THIS FRONT WILL CONTINUE TO TRANSITION WESTWARD THROUGH THE LATE
AFTERNOON AND EVENING...BEFORE STALLING IN EASTERN COLORADO (WEST
OF OUR CWA). CAA WILL CONTINUE THROUGH THE OVERNIGHT PERIOD WITH
MUCH COLDER TEMPS CONTINUING THROUGH THE DAY SUNDAY. THERE MAY BE
A PERIOD OF RETURN FLOW AND CLEARING IN SKY COVER FROM THE
SOUTHWEST...WHERE HIGHS SUNDAY MAY WARM INTO THE 40S. LOW-MID
CLOUDS MAY HOLD ON ACROSS THE EAST WHERE TEMPS MAY STRUGGLE TO
WARM ABOVE FREEZING SUNDAY AFTERNOON. NAM/SREF/RAP/HRRR CONTINUE
TO SHOW BL MOISTURE POOLING ALONG FRONTAL ZONE IN EASTERN COLORADO
WHICH COULD SUPPORT ADDITIONAL STRATUS OR FOG DEVELOPMENT. WE MAY
BE WELL MIXED ENOUGH THAT SIGNIFICANT VIS RESTRICTIONS WOULD NOT
BE AN ISSUE...AND GUIDANCE CURRENTLY KEEPS VIS ABOVE 3SM. I LEFT
PATCHY FREEZING FOG MENTION IN THE WEST...BUT NOT A LOT OF
CONFIDENCE.
SHORTWAVE TROUGH MOVES OVER THE REGION WITH SECOND ROUND OF CAA
ARRIVING BY LATE AFTERNOON. MAIN AREA OF FORCING WILL BE ASSOCIATE
WITH LOBE OF VORTICITY/ELEVATED BAROCLINIC ZONE WHICH CURRENT
TIMING FAVORS LATE AFTERNOON IN THE NORTH. MADE ADJUSTMENTS TO
BLEND WITH EVENING PERIOD AND SHOW THIS TRANSITION. ANY PRECIP IN
THE AFTERNOON WILL LIKELY BE MORE OF A RAIN/SNOW MIX BASED ON TEMP
PROFILES/WBZ HEIGHTS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 159 PM MST SAT FEB 14 2015
FOR THE EXTENDED PERIOD...THE H5 RIDGE WHICH HAD BEEN OVER THE
WESTERN HALF OF THE COUNTRY OVER THE PAST SEVERAL DAYS...WILL NOW
SHIFT FURTHER WEST FOR THE UPCOMING WEEK...MAINLY SETTING UP ALONG
THE WEST COAST. THIS IN TURN WILL ALLOW A BROAD...DEEP H5 LOW TO
ENCOMPASS ALMOST 2/3RDS OF THE COUNTRY. DURING THE COURSE OF THE
UPCOMING WEEK...THE TRI STATE REGION WILL SEE A COUPLE OF SHORTWAVES
MOVING ALONG THE BASE OF THE UPPER LOW...GIVING THE CWA A CHANCE FOR
SOME NEEDED PRECIPITATION.
FIRST SYSTEM WILL MOVE SOUTH THRU THE ROCKIES LATE SUNDAY NIGHT INTO
MONDAY NIGHT...FOLLOWED BY A WEAKER SECONDARY SYSTEM ON TUESDAY. A
STRONG SURFACE RIDGE WILL ACCOMPANY THE FIRST SHORTWAVE...EDGING
DOWN THE EAST SIDE OF THE ROCKIES IN TANDEM WITH THE SHORTWAVE. THIS
IS GOING TO PUT AN EASTERLY FETCH ACROSS THE AREA...WITH SOME
UPSLOPE POTENTIAL FOR WESTERN ZONES AS SYSTEM SLIDES THRU THE AREA.
WILL BE CONTINUING AS A RESULT THE SNOWFALL GRADIENT FROM PREVIOUS
FORECAST...WITH HIGHEST POTENTIAL OVER WESTERN ZONES...ESPECIALLY
FOR EASTERN COLORADO. MODEL DIFFERENCE IN AMT OF QPF POTENTIAL FOR
THIS SYSTEM. THINKING UPSLOPE/OROGRAPHIC EFFECTS WILL HAVE BEST
CHANCE FOR SNOW ACCUM IN AFOREMENTIONED AREAS AT 1-2" WITH 0.5-1"
FOR EASTERN ZONES. SECOND SHORTWAVE PASSES THRU CENTRAL KANSAS ON
TUESDAY WITH EASTERN ZONES IN CWA GETTING CLIPPED AS IT SWINGS THRU.
WILL GO WITH A SLIGHT CHANCE FOR -RW/-SW...WITH LITTLE TO NO ACCUM
EXPECTED.
DRY CONDITIONS EXPECTED TUESDAY NIGHT THRU THURSDAY NIGHT WITH HIGH
PRESSURE MAIN WEATHER FEATURE OVER THE CENTRAL PLAINS...AND LEE-SIDE
TROUGH FORMATION OVER THE EASTERN SIDE OF THE ROCKIES. GOING INTO
FRIDAY AND NEXT SATURDAY...GFS/ECMWF DO DIFFER ON TIMING(AS MUCH AS
12 HRS) OF NEXT SHORTWAVE TO DIG SOUTH THRU THE ROCKIES AND ACROSS
THE CENTRAL PLAINS. CONSENSUS IS TO KEEP SLIGHT CHANCE POPS IN FOR
NOW. TEMPS ARE WARM ENOUGH DURING THE DAYTIME HOURS TO SUPPORT RW
MIXING IN WITH -SW...BUT -SW AT NIGHT.
TEMPERATURES IN THE EXTENDED WILL NEAR NORMAL NUMBERS EARLY IN THE
FORECAST WITH THE ARRIVAL OF CAA WITH MONDAY SHORTWAVE...THEN
INCREASING TO ABOVE NORMAL AS RIDGE SETS UP TO EAST THRU
MIDWEEK...THEN BACK DOWN TO NEAR NORMAL BY END OF WEEK WITH ARRIVAL
OF NEXT SHORTWAVE. OVERALL HIGHS WILL MAINLY IN THE 40S WITH 50S
POSSIBLE FRIDAY...AND OVERNIGHT LOWS WILL MAINLY RANGE IN THE TEENS
WITH SOME L20S BY END OF WEEK TIMEFRAME. SOME WIND GUSTS COULD REACH
INTO THE 15-25MPH RANGE WITH GRADIENT BEHIND EACH SUBSEQUENT
SHORTWAVE PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1025 AM MST SAT FEB 14 2015
ACTIVELY MONITORING COLD FRONT JUST WEST OF KMCK...AND IFR STRATUS
JUST NORTHEAST OF THE KMCK TERMINAL. EXPECT PREVAILING MVFR AND
AT LEAST TEMPO IFR TO DEVELOP AT KMCK BY VALID TAF TIME (06Z)
BASED ON OBS/TIMING OF VIS SATELLITE. DIFFUSE BACK AND SOUTHERN
EDGE OF STRATUS MATCHES WITH GENERAL TRENDS FROM SHORT RANGE
GUIDANCE...WHICH SHOULD ALLOW FOR VFR CONDITIONS TO PREVAIL AT
KGLD THIS AFTERNOON THOUGH I COULDNT RULE OUT A BRIEF PERIOD OF
IFR CIGS AT SOME POINT. CONFIDENCE JUST TOO LOW TO ADD AT THIS
TIME. FRONT WILL STALL ACROSS EASTERN COLORADO BY THIS
EVENING...WITH BL MOISTURE POOLING JUST EAST OF THIS. THIS SHOULD
SUPPORT LIGHT FOG DEVELOPMENT AND LOWERING CIGS LATER THIS EVENING
THROUGH SUNDAY MORNING AT KGLD. CURRENTLY EXPECT LOWER CIGS/VIS TO
REMAIN IN EASTERN COLORADO...SO HAVE KEPT MVFR IN KGLD AFTER 03Z.
GUSTY EAST-NORTHEAST WINDS WILL DEVELOP THIS AFTERNOON AT BOTH
TERMINALS BEHIND COLD FRONT...DIMINISHING THIS EVENING/OVERNIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JN
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
155 PM MST SAT FEB 14 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 153 PM MST SAT FEB 14 2015
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 499 DM UPPER LOW
CENTERED OVER THE EASTERN GREAT LAKES REGION. NW FLOW IS IN PLACE
ACROSS THE PLAINS, WITH A SHORTWAVE TROUGH MOVING INTO THE
NORTHERN PLAINS FROM CANADA. AT THE SURFACE A COLD FRONT IS IN THE
PROCESS OF MOVING ACROSS OUR CWA...AND IS CURRENTLY WEST OF KGLD
NEAR THE COLORADO BORDER...EXTENDING SOUTH JUST EAST OF KDDC.
THIS FRONT WILL CONTINUE TO TRANSITION WESTWARD THROUGH THE LATE
AFTERNOON AND EVENING...BEFORE STALLING IN EASTERN COLORADO (WEST
OF OUR CWA). CAA WILL CONTINUE THROUGH THE OVERNIGHT PERIOD WITH
MUCH COLDER TEMPS CONTINUING THROUGH THE DAY SUNDAY. THERE MAY BE
A PERIOD OF RETURN FLOW AND CLEARING IN SKY COVER FROM THE
SOUTHWEST...WHERE HIGHS SUNDAY MAY WARM INTO THE 40S. LOW-MID
CLOUDS MAY HOLD ON ACROSS THE EAST WHERE TEMPS MAY STRUGGLE TO
WARM ABOVE FREEZING SUNDAY AFTERNOON. NAM/SREF/RAP/HRRR CONTINUE
TO SHOW BL MOISTURE POOLING ALONG FRONTAL ZONE IN EASTERN COLORADO
WHICH COULD SUPPORT ADDITIONAL STRATUS OR FOG DEVELOPMENT. WE MAY
BE WELL MIXED ENOUGH THAT SIGNIFICANT VIS RESTRICTIONS WOULD NOT
BE AN ISSUE...AND GUIDANCE CURRENTLY KEEPS VIS ABOVE 3SM. I LEFT
PATCHY FREEZING FOG MENTION IN THE WEST...BUT NOT A LOT OF
CONFIDENCE.
SHORTWAVE TROUGH MOVES OVER THE REGION WITH SECOND ROUND OF CAA
ARRIVING BY LATE AFTERNOON. MAIN AREA OF FORCING WILL BE ASSOCIATE
WITH LOBE OF VORTICITY/ELEVATED BAROCLINIC ZONE WHICH CURRENT
TIMING FAVORS LATE AFTERNOON IN THE NORTH. MADE ADJUSTMENTS TO
BLEND WITH EVENING PERIOD AND SHOW THIS TRANSITION. ANY PRECIP IN
THE AFTERNOON WILL LIKELY BE MORE OF A RAIN/SNOW MIX BASED ON TEMP
PROFILES/WBZ HEIGHTS.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 214 AM MST SAT FEB 14 2015
OVERALL...MOSTLY DRY FORECAST ISSUED FOR THIS EXTENDED CYCLE WITH A
GRADUAL WARMING TREND POSSIBLE BY MIDDLE OF NEXT WEEK. MOST ACTIVE
WEATHER DAY...IN TERMS OF GUSTY NORTHWEST WINDS AND POSSIBLE
CONVECTIVE RAIN/SNOW SHOWERS...FALLS ON TUESDAY WITH QUIET WEATHER
WEDNESDAY ON. MODEL DISAGREEMENT BECOMES A PROBLEM BY END OF NEXT
WEEK AS THE GFS BRINGS ANOTHER ARCTIC AIRMASS SOUTH FRIDAY/SATURDAY.
MEANWHILE...ECMWF HOLDS ARCTIC AIR BACK UNTIL SATURDAY/SUNDAY. THERE
COULD BE ANOTHER PRECIPITATION CHANCE FRIDAY NIGHT-SATURDAY NIGHT
BUT MODEL DISAGREEMENT DOESN`T INSTILL MUCH CONFIDENCE. REST OF THIS
DISCUSSION FOCUSES ON TUESDAY/WEDNESDAY FORECAST.
TUESDAY...MOST ACTIVE WEATHER DAY OF THE EXTENDED FORECAST IS
ANTICIPATED. A FEW THINGS WORKING FOR US HERE...STRONG REGIME OF
NORTHWEST FLOW WINDS ALOFT AND A SHORTWAVE TROUGH PASSING OVER THE
HIGH PLAINS. 700 MB JET OF WINDS SLIDES INTO THE AREA TUESDAY WITH
STRENGTHENING LIKELY THROUGH TUESDAY NIGHT. FAVORABLE LAPSE RATES
AND SOUNDING PROFILES INDICATE A MIXED LAYER UP TO AROUND 700 MB SO
WE SHOULD BE ABLE TO MIX STRONGER GUSTS DOWN TUESDAY. PRESENT
EXPECTATIONS ARE FOR A WINDY DAY BUT WILL NEED TO WATCH 700 MB JET
STRENGTH. GFS/ECMWF/CANADIAN ARE ALL IN AGREEMENT ON 700 MB WINDS
WHICH COULD MIX DOWN GUSTS 35-45 KTS. WILL HOLD OFF ON ADVERTISING
WINDS THAT STRONG FOR NOW. WILL NEED TO WATCH TUESDAY CLOSELY AS
THIS PATTERN TYPICALLY FAVORS HIGH WIND EVENTS OVER THE HIGH PLAINS.
IN ADDITION TO WINDS...THE SHORTWAVE COMING THROUGH SHOULD ALLOW FOR
CONVECTIVE SHOWER DEVELOPMENT. SOUNDINGS...850-500MB LAPSE RATES AND
SOME SLIGHT MUCAPE INDICATE AN UNSTABLE ATMOSPHERE. INCREASED AREA
OF SLIGHT CHANCE POPS GIVEN FROM THE EXTENDED FORECAST TO ACCOUNT
FOR THIS THINKING. THIS PATTERN IS FAIRLY COMMON FOR CONVECTIVE COOL-
SEASON SHOWERS. CURRENT FORECAST ATMOSPHERIC PROFILE SUGGESTS THAT
SNOW SHOULD BE THE PREDOMINANT PRECIPITATION TYPE. FURTHER SOUTH
WHERE WARMER TEMPERATURES ARE FORECAST...MENTIONED A RAIN/SNOW MIX.
WEDNESDAY...STRONG 700 MB JET REMAINS OVERHEAD. GRADUAL WEAKENING OF
THE JET IS ANTICIPATED. ONE CONCERN WITH THIS DAY IS THERE SHOULD BE
50-60 KTS OF WIND AT 700 MB WHICH RAISES A RED FLAG FOR POTENTIAL
HIGH WIND EVENT. HOWEVER...SOUNDINGS AND LAPSE RATES DO NOT SUPPORT
THESE GUSTS REACHING THE GROUND. IN FACT...INDICATIONS ARE FAIRLY
LIGHT WINDS...LESS THAN 25 MPH...ARE MORE LIKELY. THEREFORE...DO NOT
THINK WEDNESDAYS WINDS ARE ANYTHING TO WORRY ABOUT AT THE PRESENT
TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1025 AM MST SAT FEB 14 2015
ACTIVELY MONITORING COLD FRONT JUST WEST OF KMCK...AND IFR STRATUS
JUST NORTHEAST OF THE KMCK TERMINAL. EXPECT PREVAILING MVFR AND
AT LEAST TEMPO IFR TO DEVELOP AT KMCK BY VALID TAF TIME (06Z)
BASED ON OBS/TIMING OF VIS SATELLITE. DIFFUSE BACK AND SOUTHERN
EDGE OF STRATUS MATCHES WITH GENERAL TRENDS FROM SHORT RANGE
GUIDANCE...WHICH SHOULD ALLOW FOR VFR CONDITIONS TO PREVAIL AT
KGLD THIS AFTERNOON THOUGH I COULDNT RULE OUT A BRIEF PERIOD OF
IFR CIGS AT SOME POINT. CONFIDENCE JUST TOO LOW TO ADD AT THIS
TIME. FRONT WILL STALL ACROSS EASTERN COLORADO BY THIS
EVENING...WITH BL MOISTURE POOLING JUST EAST OF THIS. THIS SHOULD
SUPPORT LIGHT FOG DEVELOPMENT AND LOWERING CIGS LATER THIS EVENING
THROUGH SUNDAY MORNING AT KGLD. CURRENTLY EXPECT LOWER CIGS/VIS TO
REMAIN IN EASTERN COLORADO...SO HAVE KEPT MVFR IN KGLD AFTER 03Z.
GUSTY EAST-NORTHEAST WINDS WILL DEVELOP THIS AFTERNOON AT BOTH
TERMINALS BEHIND COLD FRONT...DIMINISHING THIS EVENING/OVERNIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 PM EST SAT FEB 14 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM
.SYNOPSIS...
ISSUED AT 330 PM EST SAT FEB 14 2015
DANGEROUS COLD IS IN STORE TONIGHT AND SUNDAY MORNING. WIND CHILLS
OF 20 TO 35 BELOW WILL RESULT IN FROSTBITE TIMES OF 15 MINUTES OR
LESS.
STRONG WINDS AND BLOWING SNOW WILL SUBSIDE THIS EVENING. HEAVY SNOW
SHOWERS NEAR LAKE MICHIGAN WILL END BY MIDNIGHT. WIND CHILLS WILL
RECOVER SUNDAY AFTERNOON WITH LIGHT WINDS AND BRIGHT SUNSHINE BUT
HIGH TEMPERATURES WILL BE ONLY IN THE SINGLE DIGITS.
TEMPERATURES WILL CONTINUE TO AVERAGE WELL BELOW FOR THE NEXT WEEK
OR MORE. ADDITIONAL PERIODS OF SNOW ARE LIKELY... HEAVY AT TIMES
NEAR LAKE MICHIGAN.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 330 PM EST SAT FEB 14 2015
ATTENTION SHIFTS FROM SNOW/BLOWING SNOW AND HIGH WINDS TO EXTREME
COLD TONIGHT. THE ONGOING HEADLINES WILL REMAIN IN EFFECT FOR A FEW
MORE HOURS TO COVER THE PERIODIC WHITEOUT/GROUND BLIZZARD SITUATION
THEN BECOME WIND CHILL HEADLINES.
WIND GUSTS ARE PEAKING NOW THROUGH ABOUT 5 PM BUT ARE EXPECTED TO
SHUT DOWN PRETTY QUICK THIS EVENING AS THE BOUNDARY LAYER DECOUPLES
SHORTLY AFTER 7 PM. HOWEVER SUSTAINED WINDS DO STAY UP MUCH OF THE
NIGHT WITH SPEEDS OF 10 TO 20 MPH. GUIDANCE HAS BEEN CONSISTENT
SHOWING AIR TEMPS FALLING TO 5 TO 15 BELOW WHICH SUPPORTS MIN WIND
CHILLS REACHING 25 BELOW OR LOWER OVER MUCH OF THE AREA.
INLAND CLEARING/LAND BREEZE FORMATION THIS EVENING WILL ASSIST IN
SENDING LAKESHORE SNOWS OFFSHORE. LATEST HRRR HAS THE LAKE EFFECT
SNOW BANDS SHIFTING OFFSHORE OF MKG AROUND 7 PM...HOLLAND AROUND 8
PM... SOUTH HAVEN AROUND 10 PM... AND LUDINGTON AROUND MIDNIGHT.
SURFACE RIDGING BUILDS IN QUICKLY ON SUNDAY CAUSING WINDS TO LIGHTEN
UP CONSIDERABLY. THUS WIND CHILLS RECOVER SUBSTANTIALLY IN THE
AFTERNOON UNDER BRIGHT SKIES IN FRIGID ARCTIC AIR MASS.
HI RES MODELS BEYOND 24 HOURS INDICATE MESOLOW CIRCULATION WILL
DEVELOP OVER SRN OR CNTRL LAKE MICHIGAN WITHIN MID LAKE CONVERGENCE
BAND. THIS SEEMS REASONABLE GIVEN VERY COLD/CLEAR SYNOPTIC PATTERN
AND STRONG LAND BREEZE CIRCULATIONS ON ALL SIDES OF LK MI. THIS
FEATURE SHOULD EVENTUALLY COME ONSHORE NORTH OF HOLLAND LATE SUNDAY
NIGHT OR MONDAY MORNING AS SYNOPTIC FLOW TURNS SOUTHWESTERLY.
MID LAKE MESO FEATURES CAN PRODUCE EXCESSIVE SNOW RATES... SO THIS
WILL NEED TO BE CLOSELY WATCHED. ALSO DEEPER MOISTURE ARRIVES ABOUT
THE SAME THIS FEATURE COMES ONSHORE AND THE DGZ RETURNS BACK INTO
THE CLOUD LAYER DUE TO WARMING. ADVISORY/WARNING MAY BE NEEDED
MON/MON NGT FOR WEST CENTRAL LWR MI INCLUDING MKG/LDM AREAS.
POSSIBLY BIV/GRR AS WELL DEPENDING ON MEAN LOW LEVEL WIND DIRECTION.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 330 PM EST SAT FEB 14 2015
THE LONG RANGE FORECAST PERIOD CONTINUES TO LOOK VERY COLD AND
SNOWY. ANOTHER SURGE OF ARCTIC AIR WILL BEGIN TO ARRIVE LATE TUESDAY
THROUGH TUESDAY NIGHT BEHIND THE ARCTIC COLD FRONT. MAX TEMPS
WEDNESDAY THROUGH FRIDAY WILL STRUGGLE TO REACH THE UPPER SINGLE
DIGITS TO LOWER TEENS.
THE ARCTIC FRONT WILL BRING POTENTIAL FOR A ROUND OF SNOW SHOWERS
TUESDAY WITH LAKE EFFECT SNOW SHOWERS ANTICIPATED MID TO LATE WEEK.
SIGNIFICANT HEAVY LAKE EFFECT SNOW EVENTS ARE NOT ANTICIPATED BUT
SEVERAL INCHES OF VERY DRY FLUFFY SNOW ARE POSSIBLE THROUGH MID TO
LATE WEEK.
WIND CHILL VALUES WILL BE QUITE COLD AS WELL MID TO LATE WEEK. WIND
CHILL READINGS WEDNESDAY THROUGH FRIDAY MORNING COULD BE COLDER THAN
15 DEGREES BELOW ZERO... ESPECIALLY OVER THE INTERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1210 PM EST SAT FEB 14 2015
IFR/MVFR CONDITIONS WILL CONTINUE THIS AFTERNOON DUE TO SNOW SHOWERS
AND BLOWING SNOW WITH VERY WINDY CONDITIONS. NNW WINDS WILL CONTINUE
TO GUST TO 30 TO 40 KTS THROUGH THE AFTERNOON AND EARLY EVENING
BEFORE SUBSIDING VERY QUICKLY MID TO LATE EVENING.
CONDITIONS WILL IMPROVE TO VFR THIS EVENING AND OVERNIGHT AS SKIES
CLEAR. THE ONLY EXCEPTION TO THIS IS AT KMKG WHERE SOME LOW CLOUDS
WILL LIKELY STILL LINGER THIS EVENING RESULTING IN MVFR CONDITIONS
THERE. VFR CONDITIONS WITH LIGHT NE WINDS ARE ANTICIPATED AT ALL THE
TERMINALS SUNDAY.
&&
.HYDROLOGY...
ISSUED AT 1115 AM EST SAT FEB 14 2015
THE CORE OF THE WINTER SEASONS COLDEST AIR WILL CONTINUE TO MOVE IN
THROUGH THE DAY TODAY INTO SUNDAY. TEMPERATURES WILL CONTINUE TO
TUMBLE.
THEREFORE...ICE HAS NOT BUDGED AND CONDITIONS ARE STABLE. THERE IS
IS LOW RISK THAT ANY MOVEMENT WILL OCCUR THROUGH NEXT WEEK AS THE
WARMEST HIGH TEMPERATURES IN THE NEXT SEVERAL DAYS ONLY REACH INTO
THE 20S. DAILY AVERAGE TEMPERATURES IN THE SINGLE DIGITS AND TEENS
WILL AID IN ADDITIONAL ICE FORMATION OR EXPANSION.
LIQUID CONTRIBUTION WILL REMAIN RATHER LOW DAY TO DAY. ADDITIONAL
ROUNDS OF SNOW ARE POSSIBLE THIS WEEK...ESPECIALLY ALONG THE LAKE
SHORE...BUT NOT MUCH MELTING WILL BE TAKING PLACE THROUGH THE PERIOD.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
MIZ037-038-
043-044-050-056-057-064-071.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR MIZ039-
040-045-046-051-052-058-059-065>067-072>074.
LM...NONE.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...JAM
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
919 AM MST SAT FEB 14 2015
.UPDATE...
MADE A FEW TWEAKS TO THE POPS...MAINLY TO LOWER THEM THIS
AFTERNOON OVER THE MOUNTAINS. CURRENT HIRES MODELS AND RAP DO NOT
SUPPORT MUCH UNTIL AFTER 00Z. EXTENDED THE PATCHY FOG UNTIL 18Z.
WEBCAMS ACROSS THE EASTERN PART OF THE AREA STILL SHOW SOME FOG
REMAINING. REIMER
&&
.SHORT TERM...VALID FOR TDY AND SUN...
AN UNSETTLED WEATHER PATTERN WILL BEGIN DEVELOPING TONIGHT...BUT
IN THE MEANTIME SOME AREAS WILL HAVE ONE MORE VERY WARM DAY TODAY.
TODAY...A SHALLOW COLD FRONT HAS BEEN MAKING A SLOW WESTWARD PUSH
OVERNIGHT AND LOW CLOUDS /STRATUS/ AND LIGHT FOG IN ITS WAKE HAVE
MADE IT TO MILES CITY AS OF 10 UTC. THE FRONTAL ZONE SHOULD STILL
MAKE IT TO NEAR HYSHAM AND COLSTRIP BY DAYBREAK PER RECENT MODEL
GUIDANCE...AND WE WILL CARRY PATCHY FOG IN THE FORECAST THROUGH 15
UTC ALONG AND EAST OF IT BASED ON VISIBILITY REDUCTIONS AS LOW AS
2SM OBSERVED OVERNIGHT. THE 00 UTC GUIDANCE AND MORE CONTEMPORARY
HRRR SIMULATIONS ALL SHOW THE FRONT RETREATING BACK EASTWARD TODAY
WITH 850-MB TEMPERATURES BACK UP AROUND +10 C IN SOUTH CENTRAL MT
THIS AFTERNOON...YIELDING HIGHS OVER 60 F AGAIN IN MANY AREAS WITH
MIXING TO ALMOST 750-MB ONCE MORE ON FORECAST SOUNDINGS. THE DAILY
RECORD HIGHS AT BILLINGS AND LIVINGSTON ARE BOTH 59 F AND BOTH ARE
LIKELY TO BE BROKEN. HOWEVER...WE DIDN/T GO ALL-IN WITH THE FULL
AMOUNT OF WARMING SHOWN BY THE 00 UTC BIAS-CORRECTED ECMWF /WHICH
VERIFIED VERY WELL THE LAST TWO DAYS/ SINCE MORE CLOUD COVER WILL
LIKELY EXIST TODAY. A STRONG THERMAL GRADIENT WILL EXIST IN SOUTH-
EASTERN MT WHERE THE FRONT IS NOT EXPECTED TO REACH MILES CITY AND
BROADUS UNTIL LATE DAY...AND IT WILL LIKELY NEVER GET TO BAKER...
WHERE FORECAST HIGHS ARE ONLY IN THE 20S F.
WE DID GO AHEAD AND REMOVE PRECIPITATION CHANCES IN MOST AREAS FOR
TODAY WITH WEAKER QG-FORCING ALOFT IN THE 00 UTC GUIDANCE THAN WE
SAW AT THIS TIME YESTERDAY...ALONG WITH RELATIVELY DRY MID-LEVELS.
TONIGHT...A SHORTWAVE TROUGH IN NORTHWEST FLOW WILL CROSS THE AREA
AND SUPPORT SOME CHANCE OF RAIN AND SNOW SHOWERS. THE 00 UTC MODEL
SUITE SUGGESTED A BURST OF NOTABLE QG-FORCING CENTERED ACROSS THE
FOOTHILLS OVERNIGHT...AND WE HAVE ACCORDINGLY INCREASED POPS WITH
AN INCH OF SNOW NOW ADVERTISED TONIGHT IN PLACES LIKE RED LODGE.
SUNDAY INTO SUNDAY NIGHT....A COOLER AIR MASS WILL BE IN PLACE IN
THE WAKE OF TONIGHT/S SHORTWAVE TROUGH...AND BY THE AFTERNOON AND
EVENING ANOTHER SHORTWAVE TROUGH WILL AFFECT THE AREA. THE 00 UTC
ECMWF DID BACK OFF ON THE STRENGTH OF THIS FEATURE...BUT WE CHOSE
TO CAUTIOUSLY SET THAT IDEA ASIDE SINCE IT/S AN OUTLIER SOLUTION.
THUS...WE ARE STILL EXPECTING RAIN AND MORESO SNOW SHOWERS ACROSS
AT LEAST SOUTH CENTRAL MT AND NORTH CENTRAL WY BY SUNDAY NIGHT. A
STEEP-LAPSE-RATE-ENVIRONMENT COULD YIELD CONVECTIVE ENHANCEMENT OF
SNOW SHOWERS...ESPECIALLY ALONG THE FOOTHILLS LIKE AT RED LODGE.
THE FOOTHILLS ARE FAVORED FOR HIGHER SNOW TOTALS IN A PATTERN LIKE
THIS AND WE ARE ADVERTISING 3 TO 6 INCHES IN THE FORECAST...WHICH
WILL LIKELY REQUIRE WINTER WEATHER HEADLINES AT SOME POINT. POPS
WERE ALSO INCREASED INTO THE LIKELY CATEGORY IN BILLINGS BY SUNDAY
NIGHT...BUT WE ARE CARRYING AN INCH OR LESS OF SNOW IN THE CITY AT
THIS POINT BASED ON THE 00 UTC MULTI-MODEL CONSENSUS. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
AN ACTIVE NORTHWEST FLOW WILL PREVAIL THROUGH THE EXTENDED PERIOD
WITH A STRONG RIDGE ALOFT BECOMING A FIXTURE ALONG THE PACIFIC
COAST. SHORTWAVE WITH 140KT H3 JET WILL BRING A GOOD CHANCE OF
SNOW SHOWERS TO OUR CENTRAL AND EAST PARTS MONDAY AND MONDAY
NIGHT. INSTABILITY WILL BE SHALLOWER THAN SUNDAY BUT INTERSECT
THE DENDRITIC LAYER...AND FOCUS OF SNOW SHOWER ACTIVITY SHOULD BE
ALONG INVERTED SFC-TROF AND IN NW FLOW UPSLOPE AREAS. CURRENT
INDICATIONS ARE FOR A 1 TO 3 INCH SNOWFALL FOR THE HIGHER TERRAIN
SOUTHEAST OF BILLINGS INCLUDING THE LIKES OF THE WOLF
MOUNTAINS...LAME DEER DIVIDE AND ABERDEEN HILL. HAVE RAISED POPS
AND SNOW AMTS IN THESE AREAS.
PCPN SHOULD TAPER OFF IN SOUTHEAST MT ON TUESDAY. THERE IS
POTENTIAL FOR ANOTHER PERIOD OF MOSTLY LIGHT SNOW EAST OF BILLINGS
WITH ISENTROPIC ASCENT TUESDAY NIGHT INTO WEDNESDAY...AS DOWNSLOPE
WARMING BECOMES DOMINANT IN OUR WEST AT THE SAME TIME. WILL
SUSTAIN LOW POPS TO COVER THIS POTENTIAL.
AFTER WHAT SHOULD BE A DRY AND WARMER PERIOD WEDNESDAY NIGHT TO
THURSDAY AS RIDGE AXIS SHIFTS EAST...SOME MODEL DISAGREEMENT
EXISTS HERE...IT APPEARS WE WILL SEE MORE SHORTWAVE ENERGY FROM
THE NW AND ANOTHER SURGE OF COLD ADVECTION BY THE END OF THE WEEK.
WILL KEEP CLIMO POPS FOR DAYS 7/8 TO COVER THIS FOR NOW.
AS FOR TEMPERATURES...LOOKS LIKE A COUPLE DAYS OF BELOW NORMAL
CONDITIONS FOR MOST OF OUR AREA MONDAY AND TUESDAY...WITH OUR
EAST REMAINING COLDEST PER PROXIMITY TO VERY COLD AIR SURGING INTO
THE NORTHERN PLAINS. 850MB TEMPS COOL TO THE MID TEENS BELOW ZERO
IN OUR FAR EAST BY TUESDAY...ALONG WITH A GUSTY NW WIND...SO WILL
BE QUITE CHILLY FOR PLACES SUCH AS BAKER AND EKALAKA WITH BELOW
ZERO WIND CHILLS. WARMUP WILL BEGIN ON WEDNESDAY...ESPECIALLY IN
OUR WEST AS DOWNSLOPE FLOW INCREASES...BUT SHOULD POINT OUT THAT
THE GFS HAS TRENDED TOWARD HOLDING THE SFC RIDGE IN A BIT LONGER
THAN PREVIOUS RUNS...AND INDEED THE ENSEMBLE GUIDANCE SHOWS A
PRETTY GOOD SPREAD IN TEMPS ON WEDNESDAY. WARMING TREND SHOULD
CONTINUE THURSDAY IF NOT INTO FRIDAY AS WELL...BUT AS ALREADY
MENTIONED WOULD EXPECT COOLING BY THE END OF THE WEEK.
JKL
&&
.AVIATION...
MVFR WILL PREVAIL IN EASTERN MT INTO KMLS AND KBHK WITH SOME LOW
CLOUDS AND FOG...MAINLY THIS MORNING. VFR WILL PREVAIL OTHERWISE
TODAY WITH SCT/BKN MID AND HIGH LEVEL CLOUDINESS. A COLD FRONT
WILL DROP SOUTH ACROSS THE REGION TONIGHT BRING INCREASED SHOWER
ACTIVITY AND LOCAL MVFR CONDITIONS...ESPECIALLY NEAR THE
FOOTHILLS...ALONG WITH FREQUENT MOUNTAIN OBSCURATIONS. FRIEDERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 063 033/046 027/037 020/035 022/043 028/049 031/046
1/N 25/W 64/J 32/J 11/B 11/B 22/W
LVM 062 033/044 023/036 018/041 023/050 034/049 032/048
1/N 55/W 63/J 21/B 11/B 11/B 22/W
HDN 063 029/047 026/035 016/034 018/041 026/049 026/046
1/E 24/W 45/J 42/J 22/J 11/B 22/W
MLS 044 025/043 024/032 009/026 014/034 020/042 023/040
1/E 21/B 35/J 42/J 22/J 11/E 22/J
4BQ 050 027/044 024/032 015/026 014/034 022/047 025/042
1/E 21/E 35/J 53/J 22/J 11/B 22/W
BHK 027 016/038 021/027 006/019 007/025 014/038 020/036
2/J 21/B 35/J 21/B 22/J 11/E 22/J
SHR 057 031/042 023/033 018/031 015/040 023/047 025/044
1/E 53/W 75/J 53/J 22/J 11/B 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EST SAT FEB 14 2015
.SYNOPSIS...A STRONG COLD FRONT SWEEPS ACROSS NORTH CAROLINA THROUGH
THIS EVENING. ARCTIC HIGH PRESSURE THEN BUILDS SOUTHEAST OVER THE
REGION SUNDAY INTO MONDAY. A STORM SYSTEM MOVES INTO THE SOUTHEAST
UNITED STATES BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 PM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING
TOWARD THE OHIO RIVER...WITH DECENT PRESSURE FALLS ONGOING AROUND
THE DEEPENING SURFACE LOW OVER WESTERN PENNSYLVANIA AND WIND GUSTS
BEHIND THE FRONT PEAKING AT SOME LOWER 40S KNOTS IN PARTS OF CENTRAL
INDIANA AND OHIO. THERE WERE SOME GUSTS AROUND 30KT STARTING TO GET
INTO THE MOUNTAINS OF NORTH CAROLINA AND SOUTHWEST VIRGINIA. TIMING
OF THE SURFACE FRONT AND THE ONSET OF THE GUSTY WINDS MAY RESULT IN
WINDS APPROACHING WIND ADVISORY CRITERIA A LITTLE LATER...AND THE
CURRENT PLAN IS TO START THE WIND ADVISORY IN THE NORTHWEST PIEDMONT
AT 6 PM...KEEPING THE TIMING AS IS FOR THE REST OF CENTRAL NORTH
CAROLINA AND ADDING THE COUNTIES IN THE FAR SOUTHWEST PIEDMONT AS
BUFR SOUNDINGS AND HRRR WRF 10M WIND GUSTS REALLY DO NOT
DISCRIMINATE MUCH IN THE POTENTIAL WIND FOR CENTRAL NORTH CAROLINA.
THE GFS BUFR SOUNDINGS ARE CONCERNING IN TERMS OF WIND POTENTIAL
WITH SOME MIXING SUGGESTING VALUES THAT COULD APPROACH WARNING
CRITERIA REGARDING GUSTS...IN THE MID TO UPPER 40S KNOTS AT THE TOP
OF THE MIXED LAYER. THE HRRR WRF 10M WINDS ARE SIMILAR...BUT THE NAM
BUFR SOUNDINGS SHOW WINDS SOLIDLY REMAINING IN ADVISORY CRITERIA
WHICH IS SIMILAR TO THE RAP. AS NOTED IN PREVIOUS DISCUSSIONS...THE
GREATEST WIND SHOULD BE WITH AND JUST BEHIND THE FRONT THROUGH THE
EVENING AND INTO THE EARLY OVERNIGHT WITH THE STRONG PRESSURE RISES
AND THICKNESS PACKING. BY SUNRISE SUNDAY...WINDS SHOULD STILL REMAIN
GUSTY...BUT THE 925MB WINDS ARE FORECAST BY THE GFS TO FALL FROM
AROUND 50KT THIS EVENING TO 30 TO 40KT BY 12Z SUNDAY...SO THE TIMING
OF THE WIND ADVISORY TO 6 AM SEEMS REASONABLE.
THE OVERNIGHT TEMPERATURE FORECAST IS STILL CHALLENGING...WITH THE
MAV MOS TAKING KGSO NOW ALL THE WAY DOWN TO 7F FOR A LOW...WITH THE
MET MOS AT 17F AND MOST OF THE GUIDANCE NEAR 20F FOR THE REST OF
CENTRAL NORTH CAROLINA. THE BIAS-CORRECTED MOS GUIDANCE MAY HAVE THE
BEST HANDLE ON THE SITUATION...A GOOD COMPROMISE BETWEEN WHAT COULD
BE EXPECTED BASED SOLELY ON 1000-850MB THICKNESSES WHICH WOULD
STRONGLY SUGGEST SINGLE DIGITS...AND THE MAJORITY OF THE GUIDANCE
WHICH IS SEVERAL CATEGORIES HIGHER. PLANNING ON MINIMUM TEMPERATURES
IN THE LOWER TEENS NORTHWEST TO NEAR 20 FAR SOUTH.
GIVEN THE WIND AND THE FORECAST LOWS...WIND CHILL ADVISORY CRITERIA
WILL BE CLOSE IN MANY AREAS NORTH OF U.S. 64. THE ANTICIPATED
FORECAST VALUES OF WIND AND TEMPERATURE WOULD RESULT IN MINIMUM
APPARENT TEMPERATURES LATE TONIGHT JUST BELOW ZERO FROM THE
IMMEDIATE TRIAD TO NEAR HENDERSON...AND ON THE ZERO LINE FROM ABOUT
LEXINGTON TO NEAR OR JUST NORTH OF ROCKY MOUNT. IN COORDINATION WITH
ADJACENT OFFICES AND GIVEN THE GRIDDED FORECAST VALUES OF WIND CHILL
LATE WILL ISSUE A WIND CHILL ADVISORY LATE TONIGHT AND EARLY SUNDAY
MORNING FOR MUCH OF CENTRAL NORTH CAROLINA NORTH OF A LINE FROM
ABOUT KEXX TO KRWI. THIS WILL INCLUDE RANDOLPH...CHATHAM...AND WAKE
COUNTIES TO NASH AND HALIFAX NORTH. THE FORMER THREE COUNTIES COULD
LIKELY BE ON THE MARGINS OF AN ADVISORY BUT SHOULD BE CLOSE ENOUGH
IN SOME PARTS OF THEM TO INCLUDE AT THIS POINT.
EXPECT ENOUGH FORCING AS THE LEFT ENTRANCE REGION OF 140KT 300MB AND
500MB JETS...WITH THE FRONT AND STRONG MID-LEVEL VORTICITY
ADVECTION...TO HAVE ISOLATED TO SCATTERED SHOWERS ALONG THE FRONT
DESPITE PRECIPITABLE WATER VALUES ONLY RISING TO ABOUT NORMAL...OR
JUST BELOW 0.5 INCH. THE HRRR WRF DEPICTS A NARROW BAND OF ISOLATED
TO SCATTERED SHOWERS...WITH THE RELATIVELY GREATER CHANCE IN THE
INTERSTATE 85 CORRIDOR TOWARD KRWI AND KIXA CLOSER TO THE STRONGER
FORCING ALOFT AND LIFT. BUFR SOUNDINGS TOWARD KFAY AND ESPECIALLY
TOWARD KRWI SHOW THE COINCIDENCE OF LOW LEVELS COOLING AND MOISTURE
IN THE -10C OR SLIGHTLY COLDER ZONE THAT SOME OF WHATEVER
PRECIPITATION OCCURS COULD BE MIXED RAIN AND FLURRIES. ANY NON-
LIQUID SHOULD BE QUITE FLEETING WITH THE DRY AIR SURGE MOVING INTO
THE AREA AND THE PACE OF THE FRONTAL PASSAGE.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 310 PM SATURDAY...
THE SURFACE HIGH WILL BUILD IN RAPIDLY WITH THE GRADIENT SLOWLY
RELAXING. 925MB WINDS DIMINISH ALONG WITH 850MB WINDS DIMINISHING TO
20 TO 30KT DURING THE DAY TO 00Z MONDAY. PRECIPITABLE WATER VALUES
AT OR BELOW 0.1 INCH FROM LATE TONIGHT THROUGH SUNDAY WILL RESULT IN
A DRY AIR MASS ALTHOUGH TEMPERATURES SHOULD BE CHILLY. HIGHS SHOULD
ONLY BE FROM THE UPPER 20S FAR NORTH TO POSSIBLY THE MID 30S IN THE
FAR SOUTHWEST PIEDMONT...RESULTING IN MUCH IF NOT ALL OF THE DAY
ACROSS CENTRAL NORTH CAROLINA BELOW FREEZING. SURFACE DEW POINTS
FALL TO CLOSE TO -5F TO -10F...MAKING MINIMUM RELATIVE HUMIDITIES
FROM 15 TO 20 PERCENT. IN COORDINATION WITH THE FOREST SERVICE...
WHILE THESE MINIMUM RELATIVE HUMIDITIES ARE PRETTY LOW...THE COLD
TEMPERATURES TO START...AND THE EXPECTATION THAT AS THE TEMPERATURES
WARM SLOWLY THE WINDS GRADUALLY DIMINISH...RESULT IN MORE OF AN
INCREASED FIRE DANGER CONCERN AS OPPOSED TO RED FLAG. SHOULD THE
TEMPERATURES RISE FASTER THAN EXPECTED AND THE WIND REMAIN GUSTIER
LONGER THAN ANTICIPATED WELL INTO THE 20S KNOTS...A RED FLAG WARNING
COULD BE REQUIRED.
SUNDAY NIGHT...AS THE FLOW ALOFT BACKS...CHANNELED VORTICITY ALOFT
IS FORECAST TO MOVE INTO CENTRAL NORTH CAROLINA ALONG WITH AN
INCREASE IN UPPER-LEVEL MOISTURE. BOTH THE NAM AND GFS BUFR
SOUNDINGS PROVIDE FOR GOOD MOISTURE BY THE LATE NIGHT HOURS OVER
MUCH OF CENTRAL NORTH CAROLINA AT AND ABOVE ABOUT 700MB. THE SUB-
CLOUD LAYER IS VERY DRY AT AND AROUND 850MB...SO WHILE THERE COULD
BE VIRGA WITH EVEN SOME LIMITED LIFT...THE DRY SUB-CLOUD LAYER
SHOULD PRECLUDE ANY EVEN TRACE PRECIPITATION FROM REACHING THE
GROUND. TEMPERATURES SHOULD FALL QUICKLY SUNDAY EVENING BEFORE MORE
CLOUDS START TO MOVE IN UNDER A LIGHT WIND...LOWS IN THE TEENS TO
NEAR 20.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...
...INCREASING CONFIDENCE FOR WINTER STORM CONDITIONS LATE MONDAY
THROUGH TUESDAY...
DAYTIME MONDAY WILL SEE INCREASING CLOUDINESS AHEAD OF A LEAD SHORT
WAVE THAT`S PROGGED TO ZIP ACROSS THE STATE BETWEEN 15Z MON AND 03Z
TUE. THEN THE MAIN SYSTEM...IN THE FORM OF A SOUTHERN STREAM DRIVEN
SFC LOW WILL LIFT FROM THE DEEP SOUTH MONDAY EVENING TO SOMEWHERE
ALONG OR JUST OFF THE CAROLINA COAST DURING THE DAY TUESDAY...THEN
LIFT NE AND AWAY TUESDAY NIGHT.
IMPACTS ON MONDAY: MONDAY WILL REMAIN COLD (HIGHS ONLY IN THE LOW-
MID 30S)...AND THAT WILL SET THE STAGE FOR SNOW AS THE P-TYPE...AND
EFFICIENT ACCUMULATION POTENTIAL...WITH ANY PRECIP THAT FALLS LATE
MONDAY INTO THE EARLY MORNING HOURS TUESDAY. A BAND OF LIGHT PRECIP
IS EXPECTED TO MOVE ACROSS CENTRAL NC DURING THE LATE AFTERNOON
MONDAY THROUGH LATE MONDAY EVENING...RESULTING IN PERHAPS AN INCH OR
TWO OF SNOW ACCUMULATION MAINLY ACROSS THE WESTERN PIEDMONT AND
ALONG AND SOUTH OF HWY 64...WITH PERHAPS LIGHTER AMOUNTS ACROS OUR
NE ZONES.
THEN FOR THE MAIN SYSTEM EARLY TUESDAY MORNING THROUGH WEDNESDAY
MORNING...WE STILL HAVE FAIRLY LOW CONFIDENCE GIVEN THE ON-GOING
MODEL DIFFERENCES...ESPECIALLY NOW THAT THE 12Z ECMWF IS EVEN FASTER
AND FARTHER EAST WITH THE SFC LOW...AND MORE IMPORTANTLY MUCH
FARTHER EAST WITH THE DEEPEST MOISTURE. IF THE 12Z ECWMF WERE TO
VERIFY...WE`D BE LOOKING AT A WARNING-CRITERIA SNOW EVENT (3 OR MORE
INCHES) ACROSS MUCH OF OUR CWA...MOSTLY FALLING MONDAY NIGHT INTO
TUESDAY MORNING...WITH PERHAPS SOME FREEZING RAIN MIXING IN ACROSS
OUR SE ZONES...ALL OF WHICH ENDS BY TUESDAY AFTERNOON AS THE LOW
EXITS. THE 12Z GFS...WHICH HAS BEEN BOUNCING AROUND A LOT...HAS
SHIFTED BACK EAST A BIT WITH THE LOW POSITION AND ITS SWATH OF
HEAVIEST QPF VALUES. THE 12Z GFS SUGGESTS THE FOLLOWING:
-THE COLUMN WILL REMAIN COLDEST...THUS ALLOWING FOR AN ALL-SNOW
EVENT...ACROSS OUR TRIAD ZONES...BUT THAT`S WHERE THE LEAST QPF
IS...THUS SUGGESTING SNOW AMOUNTS BARELY REACH WARNING CRITERIA.
-A SWATH OF WARNING-CRITERIA SNOW ALONG THE HWY 64 CORRIDOR...WHICH
MAY MIX WITH OR CHANGE TO FREEZING RAIN...POTENTIALLY ADDING A LAYER
OF ICE ON TOP OF ANY SNOW THAT FALLS...DURING THE DAYLIGHT HOURS
TUESDAY...BEFORE CHANGING BACK TO SNOW TUESDAY NIGHT WITH ANOTHER
LIGHT ACCUMULATION OF SNOW BEFORE ENDING EARLY WED MORNING.
-ACROSS OUR SOUTHERN AND SOUTHEAST-MOST ZONES...A BRIEF PERIOD OF
SNOW (PERHAPS AN INCH OR SO) IN THE PREDAWN HOURS TUESDAY...THEN
CHANGING TO A PERIOD OF FREEZING RAIN DURING THE DAYTIME TUESDAY.
GFS WOULD SUGGEST THAT WARNING CRITERIA ICE ACCUMULATION (A 1/4 INCH
OR MORE) IS POSSIBLE IN THIS AREA...BUT TEMPS BY TUESDAY AFTERNOON
WILL BE CLOSE TO FREEZING..AND GIVEN THE DAYTIME FACTOR...ALL OF
WHICH COULD LIMIT ICE ACCUMS. ALSO...ACROSS THE FAR SOUTHERN PORTION
OF THIS AREA (NEAR THE SC BORDER)...TEMPS MAY WARM ENOUGH TO GO TO
ALL RAIN...WHICH WOULD GREATLY LIMIT THE ICE ACCUMS.
ONE OF THE GREATEST CHALLENGES WITH THIS FORECAST WILL BE PREDICTING
THE JUXTAPOSITION OF THE COLD-ENOUGH-FOR-SNOW AIR WITH THE HEAVY
QPF...THAT COULD RESULT IN A HEAVY SNOW SWEET SPOT SOMEWHERE IN OUR
CWA. RIGHT NOW...IT`S JUST TOO SOON TO SAY IF AND WHERE THAT WILL
HAPPEN. MORE IMPORTANTLY...WE NEED TO PAY CLOSE ATTENTION TO THE
FREEZING RAIN POTENTIAL...AS SOME OF THE GUIDANCE (SUCH AS THE
NAM...WHICH APPEARS TO BE AN OUTLIER AS IT OFTEN IS) SUGGESTS ICE
ACCUMULATION MAY BE THE BIGGER STORY HERE. STAY TUNED!
AFTER THAT STORM EXITS...LOOK FOR QUIET WEATHER FROM WEDNESDAY
THROUGH FRIDAY...ALBEIT REMAINING BITTER COLD WITH TEMPS REMAINING
BELOW FREEZING FOR A PROLONGED PERIOD DURING THE LATTER HALF OF THE
WEEK..AND POSSIBILITY FOR LOW-TEENS OR UPPER-SINGLE-DIGIT LOWS
THURSDAY AND FRIDAY MORNING. THEN THE NEXT PRECIP-MAKER APPEARS TO
ARRIVE ON SATURDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1240 PM SATURDAY...
FOR THE 18Z VALID TAF PERIOD...PRIMARY AVIATION CONCERN WILL BE THE
WIND. AN ARCTIC FRONT WILL SWEEP THROUGH CENTRAL NORTH CAROLINA VERY
LATE THIS AFTERNOON THROUGH THE EVENING...BRINGING WITH IT A
POSSIBLE PERIOD OF LOW VFR CEILINGS AND A SHOWER OR TWO. AHEAD OF
THE FRONT SOUTHWEST WINDS GUST TO 30KT...THEN BEHIND THE FRONT...
WINDS TURN SHARPLY NORTHWEST AND INCREASE TO GUSTS AT LEAST INTO THE
UPPER 30S KNOTS...WITH A FEW HIGHER GUSTS LIKELY IN SPOTS. WIND
SPEEDS GRADUALLY DIMINISH SUNDAY.
BEYOND THE 18Z VALID TAF PERIOD...WINDS WILL CONTINUE TO DIMINISH
SUNDAY NIGHT AND BECOME LIGHT...AS HIGHER CLOUDS SPREAD INTO CENTRAL
NORTH CAROLINA AND GRADUALLY THICKEN AND LOWER OVER MOST OF THE AREA
BY MONDAY MORNING. A LOW PRESSURE SYSTEM MOVES INTO THE SOUTHEAST
STATES BY TUESDAY...AND THE EVENTUAL TRACK OF THE SYSTEM WILL HAVE
OBVIOUS IMPLICATIONS ON THE CENTRAL NORTH CAROLINA WEATHER. AVIATION
INTERESTS SHOULD MONITOR THE LATEST FORECASTS AND CONSIDER THE
EFFECTS OF WINTRY PRECIPITATION ALONG WITH SUB-VFR CONDITIONS...WITH
AT LEAST LIGHT WINTRY PRECIPITATION POSSIBLE AS EARLY AS THE DAYTIME
ON MONDAY AS THE AIR MASS MOISTENS FROM ABOVE. VFR CONDITIONS RETURN
BY WEDNESDAY AND CONTINUE THROUGH THURSDAY.
&&
.FIRE WEATHER...
AS OF 310 PM SUNDAY...
AS NOTED IN THE SHORT-TERM DISCUSSION ABOVE...FOLLOWING THE FIRE
WEATHER CONCERNS OF TODAY...SURFACE DEW POINTS FALL TO CLOSE TO -5F
TO -10F SUNDAY...MAKING MINIMUM RELATIVE HUMIDITIES FROM 15 TO 20
PERCENT. IN COORDINATION WITH THE FOREST SERVICE...WHILE THESE
MINIMUM RELATIVE HUMIDITIES ARE PRETTY LOW...THE COLD TEMPERATURES
TO START...AND THE EXPECTATION THAT AS THE TEMPERATURES WARM SLOWLY
THE WINDS GRADUALLY DIMINISH...RESULT IN MORE OF AN INCREASED FIRE
DANGER CONCERN AS OPPOSED TO RED FLAG. SHOULD THE TEMPERATURES RISE
FASTER THAN EXPECTED AND THE WIND REMAIN GUSTIER LONGER THAN
ANTICIPATED WELL INTO THE 20S KNOTS...A RED FLAG WARNING COULD BE
REQUIRED.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-073>078-083>086-088-089.
WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
WIND CHILL ADVISORY FROM 4 AM TO 9 AM EST SUNDAY FOR
NCZ007>011-021>027-038>041.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...RAH
AVIATION...DJF
FIRE WEATHER...DJF
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
215 PM EST SAT FEB 14 2015
.SYNOPSIS...A STRONG COLD FRONT SWEEPS ACROSS NORTH CAROLINA THROUGH
THIS EVENING. ARCTIC HIGH PRESSURE THEN BUILDS SOUTHEAST OVER THE
REGION SUNDAY INTO MONDAY. A STORM SYSTEM MOVES INTO THE SOUTHEAST
UNITED STATES BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING OUT
OF MICHIGAN AND ILLINOIS AND TOWARD THE OHIO VALLEY...WITH A BROAD
CYCLONIC FLOW AND GRADUAL PRESSURE FALLS AHEAD OF THE FRONT. ON
WATER VAPOR IMAGERY...A LEADING MID-LEVEL SHORTWAVE WAS MOVING
THROUGH CENTRAL NORTH CAROLINA WITH NUMEROUS HIGH STRATOCU OVER
PARTS OF THE AREA ALONG AND NORTH OF ABOUT U.S. 64. BEHIND THE
SHORTWAVE THERE WAS EVIDENCE OF DECREASING MOISTURE IN THE MID-
LEVELS AHEAD OF THE MORE POTENT MID-LEVEL TROUGH MOVING SOUTH OUT OF
THE GREAT LAKES. THE LATEST HRRR WRF SEEMS TO DEPICT THE TREND OF
THE CLOUD COVER FAIRLY WELL...SOME INCREASE ESPECIALLY IN THE
NORTHERN PART OF CENTRAL NORTH CAROLINA THIS MORNING WITH CLEARING
BEHIND IT...AND SOME OF THAT WAS ALREADY OCCURRING ON VISIBLE IMAGES
JUST OF THE TRIAD AS OF THIS WRITING.
NAM AND GFS BUFR SOUNDINGS...ALONG WITH RAP SOUNDINGS...INDICATE
INCREASING MIXING TAKING PLACE DURING THE AFTERNOON AS 925MB WINDS
INCREASE TO SOLIDLY 30KT BETWEEN 18Z AND 21Z. MUCH OF THE
GUIDANCE... HOWEVER...IS ALSO CONSISTENT IN A SURFACE DEW POINT
RECOVERY IN THE SOUTHWEST FLOW TODAY. RAP 1000-850MB THICKNESSES AT
12Z THIS MORNING WERE VIRTUALLY IDENTICAL TO THE SAME THICKNESS AT
KGSO...AND WITH ENOUGH SUN IN A SOUTHWEST FLOW THOSE THICKNESSES
SUPPORT HIGHS AT LEAST IN THE LOWER TO MID 50S. IT IS INTERESTING
HOW SOME OF THE MOS GUIDANCE IS SO COLD AT KRDU COMPARED TO OTHER
SITES IN CENTRAL NORTH CAROLINA...AND RUNS OF THE LAMP MOS GUIDANCE
EVEN TO 13Z FOR THERE WERE SHOWING HIGHS ONLY IN THE LOWER
40S...WITH SUBSTANTIALLY HIGHER VALUES ELSEWHERE. ANTICIPATING
ENOUGH SUN TO WARM TEMPERATURES AND CONSIDERING THE RISE IN
TEMPERATURES POSSIBLY OUTPACING THE LOW-LEVEL DEW POINT RISE...
MINIMUM RELATIVE HUMIDITIES SHOULD BE AROUND OR JUST BELOW 25
PERCENT.
MIXING HEIGHTS RISE THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT
TRANSPORT OF SOME OF THE INCREASING WINDS ALOFT TO THE SURFACE.
CURRENTLY ANTICIPATING WIND GUSTS AT LEAST AROUND 30 MPH...THE
COMBINED FORECAST OF LOW RELATIVE HUMIDITIES AND THE WIND RESULTS IN
FIRE WEATHER CONDITIONS FROM THE TRIANGLE NORTH AND WEST SIMILAR TO
THOSE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN. AS A RESULT...
OPTED TO EXPAND THE RED FLAG WARNING TO INCLUDE MUCH OF CENTRAL
NORTH CAROLINA EXCEPT FOR THE NORTHEAST PIEDMONT...WHERE MINIMUM
RELATIVE HUMIDITIES ARE FORECAST TO BE JUST A LITTLE HIGHER COMPARED
TO THE REST OF THE AREA.
AS THE FRONT APPROACHES LATE IN THE DAY...MID-LEVEL MOISTURE
INCREASES AND LANDS IN THE -10C OR SO ZONE ON BUFR AND RAP SOUNDINGS
SUCH THAT AT LEAST ISOLATED SHOWERS ARE POSSIBLE IN THE TRIAD VERY
LATE IN THE DAY...PROBABLY AFTER 5 PM. FOLLOWING THIS...SPOTTY LIGHT
SHOWERS OR SPRINKLES MAY OVERCOME AN OTHERWISE RELATIVELY DEEP ~6
THOUSAND FT SUB-CLOUD LAYER. SIMILAR TO THURSDAY...FLURRIES OR LIGHT
SNOW MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS
DURING THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY REMAINS FOR ALL BUT THE FAR SOUTHWEST PIEDMONT...THOUGH
THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN THE ADVISORY GIVEN
THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH WINDS IMMEDIATELY
BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...
...INCREASING CONFIDENCE FOR WINTER STORM CONDITIONS LATE MONDAY
THROUGH TUESDAY...
DAYTIME MONDAY WILL SEE INCREASING CLOUDINESS AHEAD OF A LEAD SHORT
WAVE THAT`S PROGGED TO ZIP ACROSS THE STATE BETWEEN 15Z MON AND 03Z
TUE. THEN THE MAIN SYSTEM...IN THE FORM OF A SOUTHERN STREAM DRIVEN
SFC LOW WILL LIFT FROM THE DEEP SOUTH MONDAY EVENING TO SOMEWHERE
ALONG OR JUST OFF THE CAROLINA COAST DURING THE DAY TUESDAY...THEN
LIFT NE AND AWAY TUESDAY NIGHT.
IMPACTS ON MONDAY: MONDAY WILL REMAIN COLD (HIGHS ONLY IN THE LOW-
MID 30S)...AND THAT WILL SET THE STAGE FOR SNOW AS THE P-TYPE...AND
EFFICIENT ACCUMULATION POTENTIAL...WITH ANY PRECIP THAT FALLS LATE
MONDAY INTO THE EARLY MORNING HOURS TUESDAY. A BAND OF LIGHT PRECIP
IS EXPECTED TO MOVE ACROSS CENTRAL NC DURING THE LATE AFTERNOON
MONDAY THROUGH LATE MONDAY EVENING...RESULTING IN PERHAPS AN INCH OR
TWO OF SNOW ACCUMULATION MAINLY ACROSS THE WESTERN PIEDMONT AND
ALONG AND SOUTH OF HWY 64...WITH PERHAPS LIGHTER AMOUNTS ACROS OUR
NE ZONES.
THEN FOR THE MAIN SYSTEM EARLY TUESDAY MORNING THROUGH WEDNESDAY
MORNING...WE STILL HAVE FAIRLY LOW CONFIDENCE GIVEN THE ON-GOING
MODEL DIFFERENCES...ESPECIALLY NOW THAT THE 12Z ECMWF IS EVEN FASTER
AND FARTHER EAST WITH THE SFC LOW...AND MORE IMPORTANTLY MUCH
FARTHER EAST WITH THE DEEPEST MOISTURE. IF THE 12Z ECWMF WERE TO
VERIFY...WE`D BE LOOKING AT A WARNING-CRITERIA SNOW EVENT (3 OR MORE
INCHES) ACROSS MUCH OF OUR CWA...MOSTLY FALLING MONDAY NIGHT INTO
TUESDAY MORNING...WITH PERHAPS SOME FREEZING RAIN MIXING IN ACROSS
OUR SE ZONES...ALL OF WHICH ENDS BY TUESDAY AFTERNOON AS THE LOW
EXITS. THE 12Z GFS...WHICH HAS BEEN BOUNCING AROUND A LOT...HAS
SHIFTED BACK EAST A BIT WITH THE LOW POSITION AND ITS SWATH OF
HEAVIEST QPF VALUES. THE 12Z GFS SUGGESTS THE FOLLOWING:
-THE COLUMN WILL REMAIN COLDEST...THUS ALLOWING FOR AN ALL-SNOW
EVENT...ACROSS OUR TRIAD ZONES...BUT THAT`S WHERE THE LEAST QPF
IS...THUS SUGGESTING SNOW AMOUNTS BARELY REACH WARNING CRITERIA.
-A SWATH OF WARNING-CRITERIA SNOW ALONG THE HWY 64 CORRIDOR...WHICH
MAY MIX WITH OR CHANGE TO FREEZING RAIN...POTENTIALLY ADDING A LAYER
OF ICE ON TOP OF ANY SNOW THAT FALLS...DURING THE DAYLIGHT HOURS
TUESDAY...BEFORE CHANGING BACK TO SNOW TUESDAY NIGHT WITH ANOTHER
LIGHT ACCUMULATION OF SNOW BEFORE ENDING EARLY WED MORNING.
-ACROSS OUR SOUTHERN AND SOUTHEAST-MOST ZONES...A BRIEF PERIOD OF
SNOW (PERHAPS AN INCH OR SO) IN THE PREDAWN HOURS TUESDAY...THEN
CHANGING TO A PERIOD OF FREEZING RAIN DURING THE DAYTIME TUESDAY.
GFS WOULD SUGGEST THAT WARNING CRITERIA ICE ACCUMULATION (A 1/4 INCH
OR MORE) IS POSSIBLE IN THIS AREA...BUT TEMPS BY TUESDAY AFTERNOON
WILL BE CLOSE TO FREEZING..AND GIVEN THE DAYTIME FACTOR...ALL OF
WHICH COULD LIMIT ICE ACCUMS. ALSO...ACROSS THE FAR SOUTHERN PORTION
OF THIS AREA (NEAR THE SC BORDER)...TEMPS MAY WARM ENOUGH TO GO TO
ALL RAIN...WHICH WOULD GREATLY LIMIT THE ICE ACCUMS.
ONE OF THE GREATEST CHALLENGES WITH THIS FORECAST WILL BE PREDICTING
THE JUXTAPOSITION OF THE COLD-ENOUGH-FOR-SNOW AIR WITH THE HEAVY
QPF...THAT COULD RESULT IN A HEAVY SNOW SWEET SPOT SOMEWHERE IN OUR
CWA. RIGHT NOW...IT`S JUST TOO SOON TO SAY IF AND WHERE THAT WILL
HAPPEN. MORE IMPORTANTLY...WE NEED TO PAY CLOSE ATTENTION TO THE
FREEZING RAIN POTENTIAL...AS SOME OF THE GUIDANCE (SUCH AS THE
NAM...WHICH APPEARS TO BE AN OUTLIER AS IT OFTEN IS) SUGGESTS ICE
ACCUMULATION MAY BE THE BIGGER STORY HERE. STAY TUNED!
AFTER THAT STORM EXITS...LOOK FOR QUIET WEATHER FROM WEDNESDAY
THROUGH FRIDAY...ALBEIT REMAINING BITTER COLD WITH TEMPS REMAINING
BELOW FREEZING FOR A PROLONGED PERIOD DURING THE LATTER HALF OF THE
WEEK..AND POSSIBILITY FOR LOW-TEENS OR UPPER-SINGLE-DIGIT LOWS
THURSDAY AND FRIDAY MORNING. THEN THE NEXT PRECIP-MAKER APPEARS TO
ARRIVE ON SATURDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1240 PM SATURDAY...
FOR THE 18Z VALID TAF PERIOD...PRIMARY AVIATION CONCERN WILL BE THE
WIND. AN ARCTIC FRONT WILL SWEEP THROUGH CENTRAL NORTH CAROLINA VERY
LATE THIS AFTERNOON THROUGH THE EVENING...BRINGING WITH IT A
POSSIBLE PERIOD OF LOW VFR CEILINGS AND A SHOWER OR TWO. AHEAD OF
THE FRONT SOUTHWEST WINDS GUST TO 30KT...THEN BEHIND THE FRONT...
WINDS TURN SHARPLY NORTHWEST AND INCREASE TO GUSTS AT LEAST INTO THE
UPPER 30S KNOTS...WITH A FEW HIGHER GUSTS LIKELY IN SPOTS. WIND
SPEEDS GRADUALLY DIMINISH SUNDAY.
BEYOND THE 18Z VALID TAF PERIOD...WINDS WILL CONTINUE TO DIMINISH
SUNDAY NIGHT AND BECOME LIGHT...AS HIGHER CLOUDS SPREAD INTO CENTRAL
NORTH CAROLINA AND GRADUALLY THICKEN AND LOWER OVER MOST OF THE AREA
BY MONDAY MORNING. A LOW PRESSURE SYSTEM MOVES INTO THE SOUTHEAST
STATES BY TUESDAY...AND THE EVENTUAL TRACK OF THE SYSTEM WILL HAVE
OBVIOUS IMPLICATIONS ON THE CENTRAL NORTH CAROLINA WEATHER. AVIATION
INTERESTS SHOULD MONITOR THE LATEST FORECASTS AND CONSIDER THE
EFFECTS OF WINTRY PRECIPITATION ALONG WITH SUB-VFR CONDITIONS...WITH
AT LEAST LIGHT WINTRY PRECIPITATION POSSIBLE AS EARLY AS THE DAYTIME
ON MONDAY AS THE AIR MASS MOISTENS FROM ABOVE. VFR CONDITIONS RETURN
BY WEDNESDAY AND CONTINUE THROUGH THURSDAY.
&&
.FIRE WEATHER...
AS OF 1055 AM SATURDAY...
AS NOTED IN THE NEAR-TERM DISCUSSION ABOVE...MIXING HEIGHTS RISE
THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT TRANSPORT OF SOME
INCREASING WINDS ALOFT TO THE SURFACE. CURRENTLY ANTICIPATING WIND
GUSTS AT LEAST AROUND 30 MPH...THE COMBINED FORECAST OF LOW RELATIVE
HUMIDITIES AND THE WIND RESULTS IN FIRE WEATHER CONDITIONS FROM THE
TRIANGLE NORTH AND WEST SIMILAR TO THOSE OVER THE SANDHILLS AND
SOUTHERN COASTAL PLAIN. AS A RESULT...OPTED TO EXPAND THE RED FLAG
WARNING TO INCLUDE MUCH OF CENTRAL NORTH CAROLINA EXCEPT FOR THE
NORTHEAST PIEDMONT...WHERE MINIMUM RELATIVE HUMIDITIES ARE FORECAST
TO BE JUST A LITTLE HIGHER COMPARED TO THE REST OF THE AREA.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE
LATER TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...DJF
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...RAH
AVIATION...DJF
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1241 PM EST SAT FEB 14 2015
.SYNOPSIS...A STRONG COLD FRONT SWEEPS ACROSS NORTH CAROLINA THROUGH
THIS EVENING. ARCTIC HIGH PRESSURE THEN BUILDS SOUTHEAST OVER THE
REGION SUNDAY INTO MONDAY. A STORM SYSTEM MOVES INTO THE SOUTHEAST
UNITED STATES BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE ARCTIC COLD FRONT MOVING OUT
OF MICHIGAN AND ILLINOIS AND TOWARD THE OHIO VALLEY...WITH A BROAD
CYCLONIC FLOW AND GRADUAL PRESSURE FALLS AHEAD OF THE FRONT. ON
WATER VAPOR IMAGERY...A LEADING MID-LEVEL SHORTWAVE WAS MOVING
THROUGH CENTRAL NORTH CAROLINA WITH NUMEROUS HIGH STRATOCU OVER
PARTS OF THE AREA ALONG AND NORTH OF ABOUT U.S. 64. BEHIND THE
SHORTWAVE THERE WAS EVIDENCE OF DECREASING MOISTURE IN THE MID-
LEVELS AHEAD OF THE MORE POTENT MID-LEVEL TROUGH MOVING SOUTH OUT OF
THE GREAT LAKES. THE LATEST HRRR WRF SEEMS TO DEPICT THE TREND OF
THE CLOUD COVER FAIRLY WELL...SOME INCREASE ESPECIALLY IN THE
NORTHERN PART OF CENTRAL NORTH CAROLINA THIS MORNING WITH CLEARING
BEHIND IT...AND SOME OF THAT WAS ALREADY OCCURRING ON VISIBLE IMAGES
JUST OF THE TRIAD AS OF THIS WRITING.
NAM AND GFS BUFR SOUNDINGS...ALONG WITH RAP SOUNDINGS...INDICATE
INCREASING MIXING TAKING PLACE DURING THE AFTERNOON AS 925MB WINDS
INCREASE TO SOLIDLY 30KT BETWEEN 18Z AND 21Z. MUCH OF THE
GUIDANCE... HOWEVER...IS ALSO CONSISTENT IN A SURFACE DEW POINT
RECOVERY IN THE SOUTHWEST FLOW TODAY. RAP 1000-850MB THICKNESSES AT
12Z THIS MORNING WERE VIRTUALLY IDENTICAL TO THE SAME THICKNESS AT
KGSO...AND WITH ENOUGH SUN IN A SOUTHWEST FLOW THOSE THICKNESSES
SUPPORT HIGHS AT LEAST IN THE LOWER TO MID 50S. IT IS INTERESTING
HOW SOME OF THE MOS GUIDANCE IS SO COLD AT KRDU COMPARED TO OTHER
SITES IN CENTRAL NORTH CAROLINA...AND RUNS OF THE LAMP MOS GUIDANCE
EVEN TO 13Z FOR THERE WERE SHOWING HIGHS ONLY IN THE LOWER
40S...WITH SUBSTANTIALLY HIGHER VALUES ELSEWHERE. ANTICIPATING
ENOUGH SUN TO WARM TEMPERATURES AND CONSIDERING THE RISE IN
TEMPERATURES POSSIBLY OUTPACING THE LOW-LEVEL DEW POINT RISE...
MINIMUM RELATIVE HUMIDITIES SHOULD BE AROUND OR JUST BELOW 25
PERCENT.
MIXING HEIGHTS RISE THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT
TRANSPORT OF SOME OF THE INCREASING WINDS ALOFT TO THE SURFACE.
CURRENTLY ANTICIPATING WIND GUSTS AT LEAST AROUND 30 MPH...THE
COMBINED FORECAST OF LOW RELATIVE HUMIDITIES AND THE WIND RESULTS IN
FIRE WEATHER CONDITIONS FROM THE TRIANGLE NORTH AND WEST SIMILAR TO
THOSE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN. AS A RESULT...
OPTED TO EXPAND THE RED FLAG WARNING TO INCLUDE MUCH OF CENTRAL
NORTH CAROLINA EXCEPT FOR THE NORTHEAST PIEDMONT...WHERE MINIMUM
RELATIVE HUMIDITIES ARE FORECAST TO BE JUST A LITTLE HIGHER COMPARED
TO THE REST OF THE AREA.
AS THE FRONT APPROACHES LATE IN THE DAY...MID-LEVEL MOISTURE
INCREASES AND LANDS IN THE -10C OR SO ZONE ON BUFR AND RAP SOUNDINGS
SUCH THAT AT LEAST ISOLATED SHOWERS ARE POSSIBLE IN THE TRIAD VERY
LATE IN THE DAY...PROBABLY AFTER 5 PM. FOLLOWING THIS...SPOTTY LIGHT
SHOWERS OR SPRINKLES MAY OVERCOME AN OTHERWISE RELATIVELY DEEP ~6
THOUSAND FT SUB-CLOUD LAYER. SIMILAR TO THURSDAY...FLURRIES OR LIGHT
SNOW MAY MIX WITH THE OTHERWISE LIQUID PRECIPITATION AS IT DEPARTS
DURING THE MID-LATE EVENING.
THE BIGGER STORY WILL BE THE WIND...COLD...AND COMBINATION OF THE
TWO IN THE FORM OF LOW WIND CHILLS...WHICH WILL FOLLOW THE FRONT.
THOUGH THE SFC LAYER MAY BRIEFLY DECOUPLE AND RESULT IN A RELATIVE
MINIMUM IN WIND AROUND SUNSET...BRUTAL CAA DRIVEN BY 3-HOURLY 7-10
MB MSL PRESSURE RISES (STRONGEST OVER WESTERN AND WEST-CENTRAL VA)
WILL CAUSE THE BOUNDARY LAYER TO MIX STRONGLY AND SUPPORT...PER BUFR
FORECAST SOUNDINGS...A FEW HOUR PERIOD OF WIND GUSTS BETWEEN 35 AND
45 MPH - SLIGHTLY WEAKER OVER THE SOUTHERN PIEDMONT AND WITH A FEW
GUSTS BETWEEN 45 AND 50 MPH POSSIBLE FROM THE NORTHERN PIEDMONT TO
THE NORTHERN AND CENTRAL COASTAL PLAIN. WHILE EXTREME FOR CENTRAL NC
STANDARDS...THIS SYSTEM LOOKS EVEN MORE POTENT THAN THE ONE FROM
THU...WHICH PRODUCED MULTIPLE WIND GUSTS BETWEEN 40 AND 45 MPH OVER
THE NW PIEDMONT...SANDHILLS...AND CENTRAL COASTAL PLAIN. A WIND
ADVISORY REMAINS FOR ALL BUT THE FAR SOUTHWEST PIEDMONT...THOUGH
THOSE COUNTIES TOO MAY ULTIMATELY BE INCLUDED IN THE ADVISORY GIVEN
THE POTENTIAL FOR A BRIEF BURST OF AROUND 40 MPH WINDS IMMEDIATELY
BEHIND THE FRONT...EVEN THERE.
THE COMBINATION OF WIND...LESSENING LATE WHEN LOW TEMPERATURES IN
THE LOW-MID TEENS TO AROUND 20 DEGREES OR SO ARE EXPECTED TO BE
ACHIEVED...WILL SUPPORT LOW MINIMUM WIND CHILL VALUES MOSTLY BETWEEN
ZERO AND TEN ABOVE. HOWEVER...CONFIDENCE IN LOW TEMPERATURES TONIGHT
IS LOWER THAN WHAT WOULD BE EXPECTED FOR A SECOND PERIOD
FORECAST...SINCE MOS GUIDANCE IS A SOLID 5-10 DEGREES HIGHER THAN 2
METER TEMPERATURE OUTPUT FROM JUST ABOUT ALL AVAILABLE MODEL
GUIDANCE. SUSPECT MOS MAY BE STRUGGLING WITH THE UNUSUALLY DEEP
MIXED LAYER IN STRONG CAA OVERNIGHT...BUT WILL DEFER TO THE DAY
SHIFT FOR WHETHER OR NOT LOWS NEED TO BE ADJUSTED DOWNWARD...WHICH
WOULD THEN SUPPORT SOME WIND CHILLS IN THE FIVE BELOW ZERO TO ZERO
RANGE GENERALLY NORTH OF HWY 64...AND WHICH WOULD NECESSITATE THE
ISSUANCE OF A WIND CHILL ADVISORY FOR THOSE AREAS.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 350 AM SATURDAY...
ARCTIC SFC HIGH PRESSURE WILL MODIFY/WEAKEN AS IT BUILDS FROM THE
UPPER MIDWEST TOWARD THE CENTRAL APPALACHIANS THROUGH MON MORNING.
SKIES WILL BE CLEAR SUNDAY IN STRONGLY SUBSIDENT CONDITIONS BEHIND
THE POTENT UPPER TROUGH FORECAST TO CROSS OUR REGION DURING THE NEAR
TERM...FOLLOWED BY INCREASING HIGH CLOUDS SUN EVE AND ESPECIALLY
OVERNIGHT...DOWNSTREAM OF THE COMPLEX AMALGAMATION OF SHORTWAVE
TROUGHS FORECAST TO AFFECT CENTRAL NC EARLY NEXT WEEK. AFTER
CONTINUED BLUSTERY CONDITIONS EARLY SUN...NW WINDS WILL LESSEN AND
CERTAINLY BECOME LESS GUSTY BY MID-LATE AFTERNOON. WITH THE LOW
LEVEL THERMAL TROUGH OVERHEAD...ONLY UPPER 20S TO LOWER 30S ARE
ANTICIPATED FOR HIGHS. SIMILARLY VERY COLD LOWS IN THE TEENS...WITH
SOME SINGLE DIGITS PROBABLE IN THE TYPICALLY COLDER AREAS OF THE
PIEDMONT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 345 AM SATURDAY...
WINTER WEATHER IS POSSIBLE EARLY NEXT WEEK...THOUGH CONFIDENCE
REMAINS LOW REGARDING POSSIBLE WINTRY PRECIP MONDAY AND TUESDAY OF
NEXT WEEK...AND THE 00Z MODEL QUITE DID NOT OFFER ANY CONVERGENCE
TOWARD A SIMILAR SOLUTION.
THE GENERAL SETUP WILL BE FOR A PAIR OF SHORTWAVES CURRENTLY OVER
OFF THE NORTHERN PACIFIC...WHICH IS A MESS ON WATER VAPOR WITH
NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE...TO DIVE SOUTHEAST
ACROSS THE ROCKIES AND THEN EAST. THE FIRST WAVE IS FORECAST TO
RACE EAST ACROSS THE OHIO VALLEY ON MONDAY...FOLLOWED BY A MORE
AMPLIFIED WAVE...WHICH ABSORBS A WEAK DISTURBANCE CURRENTLY OFF THE
CALIFORNIA BAJA...THAT CROSSES THE DEEP SOUTH ON TUESDAY. THE MAIN
QUESTIONS IN THE FORECAST ARE HOW QUICKLY PRECIP SPREADS EAST ACROSS
THE TENNESSEE VALLEY AND WHERE THE SURFACE LOW (OR MULTIPLE SURFACE
WAVES TRACK). MODELS SEEM TO BE STRUGGLING THE MOST WITH THE LEAD
WAVE...WITH THE ECMWF OUTPACING THE GFS BY 6 TO 12 HORUS RIGHT OFF
THE BAT BY BRINGING MEASURABLE PRECIP ACROSS ALL OF CENTRAL NC BY
MONDAY AFTERNOON/EVENING. DRIVEN MAINLY BY RIGHT JET ENTRANCE UPPER
DIVERGENCE...THE ECMWF LOOKS TOO WET/FAST/NORTH AND IS NOT SUPPORTED
BY THE NAM OR GFS FOR MONDAY. WILL MAINTAIN A SLIGHT CHANCE OF SNOW
ACROSS THE WESTERN/SOUTHERN PIEDMONT MONDAY AFTERNOON AND EARLY
EVENING TO ACCOUNT FOR THIS POSSIBILITY. EXPECT HIGHS MONDAY TO BE
LOWER THAN GUIDANCE GIVEN THAT THERE SHOULD BE WIDESPREAD MID/HIGH
CLOUDS....EVEN WITHOUT PRECIP...AFTER A VERY COLD START AND GUIDANCE
IS CLOSE TO FULL SUN THICKNESS VALUES. HIGHS 30-35.
THE MORE IMPACTFUL WEATHER POTENTIAL COMES MONDAY NIGHT AND TUESDAY
AS STRONGER HEIGHT FALLS SPREAD ACROSS THE SOUTHEAST AHEAD OF THE
SECOND AND MORE AMPLIFIED SHORTWAVE. A SURFACE LOW IS EXPECTED
DEVELOP FROM THE GULF COAST TOWARD THE CAROLINA COAST DURING THE DAY
TUESDAY...THOUGH THE LOW TRACK IS STILL VERY MUCH IN QUESTION. THE
GFS IS SEVERAL MB LOWER AND FURTHER WEST THAN THE WEAKER/OFFSHORE
ECMWF. AS USUAL...THIS WILL PLAY A MAJOR ROLE IN EXACTLY WHERE A
TRANSITION ZONE (LIKELY SHARP) BETWEEN MORE FROZEN AND MORE LIQUID
PRECIP WOULD END UP. BASED ON THE PRECEDING AIRMASS MONDAY/MONDAY
NIGHT AND PTYPE NOMOGRAMS...CURRENTLY FEEL THAT PRECIP WILL STAND A
GOOD CHANCE OF BEING ALL SNOW AT ONSET MONDAY NIGHT/EARLY TUESDAY
AND THAT A LARGER-THAN-TYPICAL AREA COULD SEE SEVERAL HOURS OF A
LEAST A WINTRY MIX TUESDAY. SURFACE TEMPS WOULD ALSO BE FAVORABLE
FOR ACCUMULATION. THUS...WHILE CONFIDENCE IN THE DETAILS OF THE
FORECAST IS LOW...CONFIDENCE IS MEDIUM AND SLOWLY GROWING THAT THIS
SHOULD BE AT LEAST AN ADVISORY EVENT.
GIVEN THAT MODELS STILL AREN`T INITIALIZING WITH MUCH INFORMATION ON
THE MAIN PLAYERS IN THIS SYSTEM AND ARE STILL VERY DIFFERENT...THE
BEST COURSE OF ACTION WITH THIS FORECAST PACKAGE MAY BE TO JUST
CONTINUE THE ADVERTISED PTYPES.
THE SURFACE LOW WILL LIFT OFF TO THE NORTHEAST WEDNESDAY...WITH
PRECIP ENDING (POSSIBLY AS SNOW) BY WEDNESDAY AFTERNOON. ANOTHER
BLAST OF ARCTIC AIR IS EXPECTED ON ITS HEELS FOR LATE WEEK AS THE
TRAIN OF SHORTWAVES INTO THE EAST COAST TROUGH CONTINUES. MODELS
ARE TRENDING COLDER FOR THURS THROUGH SATURDAY...WITH ANOTHER ROUND
OF LOWS IN THE TEENS OR SINGLE DIGITS AND HIGHS IN THE 30S POSSIBLE.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1240 PM SATURDAY...
FOR THE 18Z VALID TAF PERIOD...PRIMARY AVIATION CONCERN WILL BE THE
WIND. AN ARCTIC FRONT WILL SWEEP THROUGH CENTRAL NORTH CAROLINA VERY
LATE THIS AFTERNOON THROUGH THE EVENING...BRINGING WITH IT A
POSSIBLE PERIOD OF LOW VFR CEILINGS AND A SHOWER OR TWO. AHEAD OF
THE FRONT SOUTHWEST WINDS GUST TO 30KT...THEN BEHIND THE FRONT...
WINDS TURN SHARPLY NORTHWEST AND INCREASE TO GUSTS AT LEAST INTO THE
UPPER 30S KNOTS...WITH A FEW HIGHER GUSTS LIKELY IN SPOTS. WIND
SPEEDS GRADUALLY DIMINISH SUNDAY.
BEYOND THE 18Z VALID TAF PERIOD...WINDS WILL CONTINUE TO DIMINISH
SUNDAY NIGHT AND BECOME LIGHT...AS HIGHER CLOUDS SPREAD INTO CENTRAL
NORTH CAROLINA AND GRADUALLY THICKEN AND LOWER OVER MOST OF THE AREA
BY MONDAY MORNING. A LOW PRESSURE SYSTEM MOVES INTO THE SOUTHEAST
STATES BY TUESDAY...AND THE EVENTUAL TRACK OF THE SYSTEM WILL HAVE
OBVIOUS IMPLICATIONS ON THE CENTRAL NORTH CAROLINA WEATHER. AVIATION
INTERESTS SHOULD MONITOR THE LATEST FORECASTS AND CONSIDER THE
EFFECTS OF WINTRY PRECIPITATION ALONG WITH SUB-VFR CONDITIONS...WITH
AT LEAST LIGHT WINTRY PRECIPITATION POSSIBLE AS EARLY AS THE DAYTIME
ON MONDAY AS THE AIR MASS MOISTENS FROM ABOVE. VFR CONDITIONS RETURN
BY WEDNESDAY AND CONTINUE THROUGH THURSDAY.
&&
.FIRE WEATHER...
AS OF 1055 AM SATURDAY...
AS NOTED IN THE NEAR-TERM DISCUSSION ABOVE...MIXING HEIGHTS RISE
THIS AFTERNOON WHICH SHOULD ALLOW FOR EFFICIENT TRANSPORT OF SOME
INCREASING WINDS ALOFT TO THE SURFACE. CURRENTLY ANTICIPATING WIND
GUSTS AT LEAST AROUND 30 MPH...THE COMBINED FORECAST OF LOW RELATIVE
HUMIDITIES AND THE WIND RESULTS IN FIRE WEATHER CONDITIONS FROM THE
TRIANGLE NORTH AND WEST SIMILAR TO THOSE OVER THE SANDHILLS AND
SOUTHERN COASTAL PLAIN. AS A RESULT...OPTED TO EXPAND THE RED FLAG
WARNING TO INCLUDE MUCH OF CENTRAL NORTH CAROLINA EXCEPT FOR THE
NORTHEAST PIEDMONT...WHERE MINIMUM RELATIVE HUMIDITIES ARE FORECAST
TO BE JUST A LITTLE HIGHER COMPARED TO THE REST OF THE AREA.
LINGERING BLUSTERY CONDITIONS ON SUNDAY...IN CONJUNCTION WITH LOW
RELATIVE HUMIDITY VALUES AROUND 20 PERCENT...MAY RESULT IN YET
ANOTHER DAY OF ELEVATED FIRE RISK...PARTICULARLY OVER THE EASTERN
HALF OF CENTRAL NC WHERE WINDS WILL BE STRONGEST (GUSTS 25 TO 30
MPH) RELATIVELY LONGEST (THROUGH EARLY-MID AFTERNOON). COLD
TEMPERATURES ONLY IN THE 20S TO LOWER 30S MAY MITIGATE THE OVERALL
THREAT...HOWEVER. WE WILL COORDINATE WITH THE NC FOREST SERVICE
LATER TODAY REGARDING FIRE RISK FOR SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE TEMPERATURE RECORDS FOR FEBRUARY 15 AND 16:
RECORD LOWS
GSO RDU FAY
FEBRUARY 15: 6 IN 1943 6 IN 1899 12 IN 1943
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 15: 28 IN 1943 29 IN 1943 36 IN 1965
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM EST THIS EVENING FOR
NCZ007-021>025-028-038>043-073>078-083>086-088-089.
WIND ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST SUNDAY FOR
NCZ008>011-024>028-040>043-074>078-085-086-088-089.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST SUNDAY FOR
NCZ007-021>023-038-039.
&&
$$
SYNOPSIS...DJF
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...SMITH
AVIATION...DJF
FIRE WEATHER...RAH
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
447 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SENT A QUICK UPDATE TO COVER INCLUDING THE SOUTHERN ZONES IN A
WINTER WEATHER ADVISORY.
MESO ANAL INDICATES THE ARCTIC COLD FRONT AT MID DAY IS ENTERING
FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE OF SNOW SHOWERS AND
SQUALLS ALONG THE SHARP CONVERGENCE ZONE. LOCALLY WE HAVE A
WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING FORCED BY STRONG WARM
ADVECTION AHEAD OF THE APPROACHING FRONT. HIGHER ELEVATIONS TO OUR
WEST HAVE EXPERIENCED SMALL ACCUMS OF AN INCH OR 2...WHILE JUST
EAST OF THE HIGHER TERRAIN AMOUNTS HAVE BEEN OF THE NUISANCE OR
DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...AGAIN TODAY MODEL TRENDS OVER CONTINUE
TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER SOUTHERN STREAM
SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT LAKES REGION AND
NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM PRECIP STAYING
CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
CURRENT FCST LOOKS GOOD. MINOR ADJUSTMENTS MADE TO THE 21Z TAFS.
EVEN SOME THUNDER WITH THE SNOW SQUALLS.
EARLIER DISCUSSION BELOW.
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066.
WIND ADVISORY UNTIL NOON EST SUNDAY FOR PAZ012-017>019-024>028-
033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING UNTIL 10 AM EST MONDAY FOR PAZ004>006-010-
011-017-024-033.
HIGH WIND WARNING UNTIL NOON EST SUNDAY FOR PAZ036-056>059-
063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
400 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SENT A QUICK UPDATE TO COVER INCLUDING THE SOUTHERN ZONES IN A
WINTER WEATHER ADVISORY.
MESO ANAL INDICATES THE ARCTIC COLD FRONT
AT MID DAY IS ENTERING FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE
OF SNOW SHOWERS AND SQUALLS ALONG THE SHARP CONVERGENCE ZONE.
LOCALLY WE HAVE A WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING
FORCED BY STRONG WARM ADVECTION AHEAD OF THE APPROACHING FRONT.
HIGHER ELEVATIONS TO OUR WEST HAVE EXPERIENCED SMALL ACCUMS OF AN
INCH OR 2...WHILE JUST EAST OF THE HIGHER TERRAIN AMOUNTS HAVE
BEEN OF THE NUISANCE OR DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...AGAIN TODAY MODEL TRENDS OVER CONTINUE
TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER SOUTHERN STREAM
SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT LAKES REGION AND
NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM PRECIP STAYING
CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
226 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /THROUGH TONIGHT/...
SENT A QUICK UPDATE TO COVER INCLUDING THE SOUTHERN ZONES IN A
WINTER WEATHER ADVISORY.
MESO ANAL INDICATES THE ARCTIC COLD FRONT
AT MID DAY IS ENTERING FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE
OF SNOW SHOWERS AND SQUALLS ALONG THE SHARP CONVERGENCE ZONE.
LOCALLY WE HAVE A WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING
FORCED BY STRONG WARM ADVECTION AHEAD OF THE APPROACHING FRONT.
HIGHER ELEVATIONS TO OUR WEST HAVE EXPERIENCED SMALL ACCUMS OF AN
INCH OR 2...WHILE JUST EAST OF THE HIGHER TERRAIN AMOUNTS HAVE
BEEN OF THE NUISANCE OR DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
ALTHOUGH WINDS WILL GRADUALLY RELAX INTO MON...COMBINATION OF
COLD TEMPS AND WIND JUSTIFIES THE WIND CHILL WATCH CURRENTLY IN
EFFECT THROUGH THAT 36HR PERIOD. THIS WILL LIKELY NEED TO BE
UPGRADED TO A WARNING AS EVENT WINDOW APPROACHES. WILL ALSO NEED
TO STRONGLY CONSIDER A WIND ADVISORY ESP FOR HIGHER TERRAIN AND
NW-SE ALIGNED VALLEYS ACROSS SOUTHERN AREAS SAT NIGHT INTO EARLY
SUN WITH PEAK WIND GUSTS IN THE 40-50 MPH RANGE.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS
CONTINUE TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER
SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT
LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM
PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/RXR
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
110 PM EST SAT FEB 14 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE COMMONWEALTH THIS
AFTERNOON AND EVENING. THE COLDEST AIR OF THE SEASON WILL BE WITH
US SUNDAY INTO EARLY MONDAY ALONG WITH DANGEROUSLY LOW WIND CHILLS
OF 20 TO 35 BELOW ZERO. THE NEXT CHANCE FOR SNOW WILL BE AROUND
MID WEEK AS AN AREA OF LOW PRESSURE MOVES NORTHEAST FROM THE GULF
COAST STATES.
&&
.NEAR TERM /THROUGH TONIGHT/...
MESO ANAL INDICATES THE ARCTIC COLD FRONT AT MID DAY IS ENTERING
FAR NWRN PA. RADAR SHOWS A DEVELOPING LINE OF SNOW SHOWERS AND
SQUALLS ALONG THE SHARP CONVERGENCE ZONE. LOCALLY WE HAVE A
WIDESPREAD AREA OF FAIRLY LIGHT SNOW BEING FORCED BY STRONG WARM
ADVECTION AHEAD OF THE APPROACHING FRONT. HIGHER ELEVATIONS TO OUR
WEST HAVE EXPERIENCED SMALL ACCUMS OF AN INCH OR 2...WHILE JUST
EAST OF THE HIGHER TERRAIN AMOUNTS HAVE BEEN OF THE NUISANCE OR
DUSTING VARIETY.
HIGH RES MODELS CONTINUE TO INDICATE A LINE OF SNOW SQUALLS NOW
ENTERING NW PORTIONS OF THE REGION...PROGRESSING OFF TO THE EAST
THEREAFTER. RAP DEVELOPS SOME IMPRESSIVE INSTABILITY FOR MID
FEBRUARY...WITH STEEPENING LOW-MID LEVEL LAPSE RATES AND EVEN
COOKING UP A COUPLE OF HUNDRED JOULES OF CAPE IN RESPONSE TO
RAPIDLY FALLING HEIGHTS AND TEMPS ALOFT.
CURRENT TIMING HAS THE COLD FRONT/SQUALL LINE MOVING THROUGH
BRADFORD AROUND 20Z/3PM...MOVING EAST TO A LINE FROM JOHNSTOWN
THROUGH CLEARFIELD UP INTO COUDERSPORT AROUND 21Z/4PM...AND INTO
RENOVO-STATE COLLEGE-ALTOONA BY 22Z/5PM. EAST OF THE CENTRAL
MOUNTAINS THE HRRR TRIES TO MAKE THE SQUALL LINE MORE
DISORGANIZED SO TIMING MAY BE MORE NEBULOUS.
I WOULD NOT RULE OUT A LITTLE THUNDER SNOW AS THE FORCING LOOKS
ESPECIALLY ROBUST FOR THE TIME OF YEAR.
TEMPS IN THE 20S TO LOWER 30S AHEAD OF THE FRONT AND THE
POTENTIAL FOR WET/PRE-TREATED ROADS FROM ANY LIGHT SNOW AHEAD OF
THE FRONT...WILL LEAD TO A DANGEROUS...FLASH FREEZE SETUP AS THE
ARCTIC FRONT PLOWS EAST ACROSS THE STATE ACCOMPANIED BY ONE OR TWO
DISTINCT NORTH/SOUTH BANDS OF BLINDING SNOW SQUALLS...SHARPLY
FALLING TEMPS...AND WIND GUSTS OF 35-45 MPH. HAZARDOUS INTERSTATE
TRAVEL CONDITIONS ARE EXPECTED TO DEVELOP FROM WEST TO EAST THIS
AFTERNOON.
A WINTER WX ADVISORY COVERS MUCH OF CENTRAL PA THROUGH 12Z SUNDAY
AS MODEL BLENDED QPF COMBINED WITH SLR/S OF CLOSE TO 20/1 SUPPORT
A GENERAL 2-4 INCH SNOWFALL TODAY AND TONIGHT FROM THE ONE-TWO
PUNCH OF THE ARCTIC FRONT...THEN PERIODS OF SNOW/SNOW SHOWERS
ASSOCIATED WITH THE PASSAGE OF THE SE DIGGING CLOSED UPPER LOW.
THE HIGHER SNOWFALL AMOUNTS WILL BE CONFINED TO MAINLY THE NW
MTNS...WRN POCONOS AND ENDLESS MTNS OF NEPA...AND THE LAUREL
HIGHLANDS IN THE SOUTHWEST.
EVEN THOSE LOCATIONS THAT FALL SHORT OF ADVISORY CRITERIA SNOW
WILL HAVE TO CONTEND WITH AREAS OF BLOWING/DRIFTING SNOW BEHIND
THE COLD FRONT LATE TODAY AND TONIGHT. BUFKIT SOUNDINGS SUPPORT
FREQUENT GUSTS IN THE 35-40KT RANGE IN WAKE OF FRONT ACROSS MUCH
OF THE CENTRAL RIDGE AND VALLEY REGION...LASTING THRU TONIGHT.
EVEN HIGHER GUSTS...OCNLY UP TO BETWEEN 45-50 KTS APPEAR LIKELY
ACROSS THE REGION NEAR AND TO THE SE OF I-81...SO THE HIGH WIND
WATCH TRANSITIONED TO A HIGH WIND WARNING THERE. THE HIGH WIND
WARNING AND WIND ADVISORY RUNS THROUGH NOON SUNDAY.
THE LOW SHOULD BE QUICKLY RE-DEVELOPING OVER EASTERN PA OR OVER
THE COASTAL WATERS BY EVENING...WITH THE LOCAL AREA TRANSITIONING
INTO A POST COLD FRONTAL FLOW PATTERN. WITH THE LOW EXPECTED TO
BE DEEPENING RAPIDLY...STRONG GUSTY WINDS WILL DEVELOP AND
CONTINUE INTO THE OVERNIGHT CAUSING WIND CHILLS TO DIP TO
DANGEROUSLY LOW LEVELS OVER THE ENTIRE FCST AREA. AFTER
COLLABORATION WITH SURROUNDING WFOS WE DECIDED TO ISSUE A WIND
CHILL WARNING FOR THE ENTIRE CWA TONIGHT THROUGH MONDAY MORNING.
ACTUAL AIR TEMPERATURES WILL PLUMMET TONIGHT TO BETWEEN 5 AND 15
DEGREES BELOW ZERO ACROSS THE NORTHWEST MOUNTAINS AND LAUREL
HIGHLANDS...AND SETTLE BETWEEN ZERO AND 5 ABOVE THROUGHOUT THE
LARGER METRO AREAS OF THE LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /SUNDAY/...
SHALLOW STRATO CU CLOUDS CLOUDS SHOULD BREAK ALONG AND TO THE SE
OF THE I-99/I-80/RT 220 CORRIDOR SUNDAY AS HIGH PRESSURE BUILDS
EAST FROM THE OHIO VALLEY LATE IN THE DAY. SCATTERED FLURRIES WILL
OCCUR SUNDAY AFTERNOON ACROSS THE CENTRAL ZONES...WHILE THE NW
MTNS AND LAURELS COULD SEE LOCALLY UP TO ANOTHER ADDITIONAL
COATING TO ONE INCH FROM SCATTERED SNOW SHOWERS.
HIGH TEMPERATURES WILL STRUGGLE TO REACH 5 BELOW ZERO ACROSS THE
NORTHWEST MOUNTAINS...AND WILL ONLY MAKE IT TO 10 TO 12 DEGREES
ABOVE ZERO ACROSS THE LOWER SUSQUEHANNA VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE NEXT WEEK AS STRONG RIDGE OVER WESTERN U.S. CONTINUES TO
DIRECT POLAR AIR INTO THE EASTERN U.S. VIA PERSISTENT TROUGH.
ALTHOUGH WINDS WILL GRADUALLY RELAX INTO MON...COMBINATION OF
COLD TEMPS AND WIND JUSTIFIES THE WIND CHILL WATCH CURRENTLY IN
EFFECT THROUGH THAT 36HR PERIOD. THIS WILL LIKELY NEED TO BE
UPGRADED TO A WARNING AS EVENT WINDOW APPROACHES. WILL ALSO NEED
TO STRONGLY CONSIDER A WIND ADVISORY ESP FOR HIGHER TERRAIN AND
NW-SE ALIGNED VALLEYS ACROSS SOUTHERN AREAS SAT NIGHT INTO EARLY
SUN WITH PEAK WIND GUSTS IN THE 40-50 MPH RANGE.
RECORD LOWS FOR THE DATE EARLY MONDAY APPEAR LIKELY. LOWS EARLY
MONDAY MORNING UNDER CLEAR TO PARTLY CLOUDY SKIES WITH DIMINISHING
WIND WILL EASILY AVERAGE 10-15 BELOW ZERO ACROSS THE NRN AND
WESTERN MTNS...AND 5-10 BELOW ZERO THROUGHOUT MUCH OF THE CENTRAL
RIDGE AND VALLEY REGION. SOME PROTECTED VALLEYS ACROSS THE NORTH
COULD DIP TO NEAR 25 BELOW BETWEEN 09-12Z MONDAY. SURFACE HIGH
WILL PROPAGATE ACROSS CENTRAL PA MONDAY AND MONDAY NIGHT...MOVING
OFFSHORE ON TUESDAY.
STILL AT LEAST SOME POTENTIAL INDICATED FOR SOME PHASING OF
NORTHERN AND SOUTHERN STREAM WAVES OVER THE GULF COAST AND
SOUTHEASTERN U.S. BY LATER TUE INTO WED...BRINGING THE CHANCE OF
SNOW TO THE REGION. HOWEVER...MODEL TRENDS OVER PREVIOUS FEW DAYS
CONTINUE TO LEND CREDENCE TOWARD A MORE SUPPRESSED/FLATTER
SOUTHERN STREAM SYSTEM WITH THE ARCTIC AIR DOMINATING THE GREAT
LAKES REGION AND NE U.S. AND THE BULK OF ANY STEADIER/STRATIFORM
PRECIP STAYING CONFINED TO THE SE U.S. AND MAYBE THE VIRGINIAS.
YET ANOTHER SURGE OF EXTREMELY COLD AIR RIDES IN ON PERSISTENT
NORTHWEST LATE NEXT WEEK...AS A MASSIVE RIDGE OF SURFACE HIGH
PRESSURE COVERS THE EASTERN HALF OF THE CONUS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE ARCTIC COLD FRONT IS ENTERING NWRN PA AS OF MID DAY....
A SFC LOW ASSOCIATED WITH THE COLD FRONT TRACK ESE ACROSS THE NRN
MID ATLANTIC STATES THIS AFTERNOON BEFORE RAPIDLY INTENSIFYING
JUST OFFSHORE SRN NEW ENGLAND TONIGHT INTO EARLY SUNDAY.
THE ARCTIC COLD FRONT WILL MOVE THROUGH THE FLYING AREA AND BE
THE FOCUS FOR LOCALLY HEAVY SNOW SQUALLS THIS AFTERNOON AND
EVENING...WITH AN AREA OF PRE-FRONTAL LIGHT SNOW AND MVFR/IFR
CONDITIONS ALREADY IMPACTING THE WRN 1/3 TO 1/2 OF THE AIRSPACE.
OVERALL EXPECT PREVAILING IFR ACROSS THE HIGHER ELEVATION SITES
FROM JST UP THROUGH BFD. CENTRAL TERMINALS WILL SEE PERIODS OF
IFR BUT MVFR WILL MORE LIKELY BE THE PREVAILING FLIGHT CAT.
PREVAILING VFR WITH PERIODS OF MVFR CAN BE EXPECTED AT THE SERN
SITES. USED 1HR TEMPO TO SHOW BEST TIME WINDOW FOR HEAVY SNOW AND
REDUCED CONDITIONS ASSOCIATED WITH EXPECTED SNOW SQUALL
ACTIVITY...WITH A SHARP DROP IN VIS TO 1/2 MILE OR LESS. WIND WILL
BECOME THE MAIN CONCERN LATER TONIGHT INTO EARLY SUNDAY WITH
PEAK GUSTS IN THE 35-45KT RANGE FROM AROUND 300 DEGREES. MVFR/IFR
IN OCNL SHSN WILL LINGER OVER THE WRN TERMINALS INTO SUNDAY WITH
GRADUAL IMPROVEMENT EXPECTED DURING THE DAY. ELSEWHERE LOOK FOR A
RETURN TO LOW VFR WITH CIGS BTWN 3000-5000`.
OUTLOOK...
MON-TUE...VFR/NO SIG WX.
WED-THU...MVFR/IFR SHSN WEST. VFR/MVFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-017>019-024>028-033-037-041-042-045-046-049>053-058.
WIND ADVISORY FROM 7 PM THIS EVENING TO NOON EST SUNDAY FOR
PAZ012-017>019-024>028-033>035-037-041-042-045-046-049>053.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST MONDAY
FOR PAZ012-018-019-025>028-034>037-041-042-045-046-049>053-
056>059-063>066.
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 10 AM EST MONDAY
FOR PAZ004>006-010-011-017-024-033.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON EST SUNDAY
FOR PAZ036-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/RXR
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
319 PM CST SAT FEB 14 2015
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
WATCHING AN AREA OF RADAR RETURNS ACROSS THE CENTRAL
DAKOTAS...WITH OBS SHOWING SNOW ACROSS ND BUT YET TO SEE ANYTHING
OF SIGNIFICANCE ACROSS SD. WEB CAM AT LEMMON DOES APPEAR TO SHOW
LIGHT SNOW HAS BEGUN. STILL A DECENT AMOUNT OF DRY AIR TO OVERCOME
BASED ON RAP SOUNDINGS BUT IMAGINE MBG WILL BEGIN REPORTING -SN
BEFORE TOO LONG. HAVE SCALED BACK SNOW AMOUNTS JUST A BIT ACROSS
THE EASTERN CWA GIVEN THE MOISTENING OF THE ATMOSPHERE THAT WILL
HAVE TO TAKE PLACE FIRST. SHOULD STILL BE ABLE TO SEE AROUND IN
INCH FOR MOST PLACES ALONG AND EAST OF THE JAMES VALLEY. SYSTEM
LOOKS TO BE OUT OF HERE BY SUNDAY AFTERNOON WITH WARMER
TEMPERATURES MOVING BACK IN. ANOTHER COLD FRONT IN ON TRACK TO
SWEEP SOUTH ACROSS THE AREA MONDAY AFTERNOON...BRINGING ANOTHER
SHOT OF GUSTY NORTH WINDS AND COLD AIR TO THE REGION.
.LONG TERM...TUESDAY THROUGH SATURDAY
VERY GOOD AGREEMENT WITH THE MODELS IN THE LONG TERM WITH THE UPPER
LEVEL LONG WAVE PATTERN ALONG WITH THE SURFACE FEATURES. THE LONG
TERM LOOKS TO HAVE MAINLY BELOW TO MUCH BELOW NORMAL TEMPERATURES
THROUGH AT THE LEAST TUESDAY...WEDNESDAY AND THURSDAY. A LARGE UPPER
LEVEL LOW PRESSURE TROUGH ACROSS EASTERN CANADA AND THE EASTERN US
THROUGH MOST OF THE PERIOD WILL BRING PREVAILING FLOW FROM CANADA
AND THE ARCTIC. AT THE SURFACE...A COUPLE HIGH PRESSURE AREAS WILL
MOVE ACROSS THE REGION FROM THE NORTH. THERE WILL ALSO BE A FEW
WEAK UPPER LEVEL SHORT WAVE TROUGHS AND SURFACE COLD FRONTS MOVING
THROUGH BRINGING SOME CHANCES OF LIGHT SNOW/FLURRIES WITH THEM.
LEFT IT MAINLY DRY THROUGH THE LONG TERM AT THIS TIME. TEMPERATURES
MAY RISE CLOSER TO NORMAL TO SLIGHTLY ABOVE NORMAL OUT WEST BY
FRIDAY AND SATURDAY.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN UPPER LEVEL LOW PRESSURE TROUGH ALONG WITH WAA WILL SPREAD LIGHT
SNOW AND LOWERING CEILINGS ACROSS THE REGION THROUGH THE AFTERNOON
AND EARLY TONIGHT. EXPECT IFR/MVFR CEILINGS AND VISIBILITIES AT
MBG...ABR AND ATY FOR A TIME AS THIS SYSTEM MOVES THROUGH. PIR MAY
HAVE A BRIEF PERIOD OF LIGHT SNOW THIS AFTERNOON BUT OVERALL
EXPECT THEM TO BE DRY. ALSO...EXPECT A PERIOD OF MVFR CEILINGS AT
PIR AS LOW CLOUDS RETURN BACK TO THE NORTH AND EAST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...TMT
LONG TERM...MOHR
AVIATION...MOHR
WEATHER.GOV/ABERDEEN