000
FXUS63 KGID 091603
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1003 AM CST MON DEC 9 2013

.UPDATE...
ISSUED AT 1001 AM CST MON DEC 9 2013

THE WIND CHILL ADVISORY HAS BEEN ALLOWED TO EXPIRE AS BOTH
TEMPERATURES AND WIND CHILL VALUES HAVE RISEN THIS MORNING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM CST MON DEC 9 2013

WITH ESSENTIALLY ZERO RISK FOR PRECIPITATION DURING THE NEXT 24
HOURS...THE MAIN ISSUES ARE THE ONGOING NEAR-ADVISORY TO ADVISORY
LEVEL WIND CHILLS NEARLY AREA-WIDE THIS MORNING...ALONG WITH A
SOMEWHAT TRICKY TEMP FORECAST REGARDING BOTH THE HIGHS AND
LOWS...AS TODAY WILL START THE PROVERBIAL BATTLE BETWEEN SUN
AND SNOW COVER.

IN THE BIG PICTURE MID/UPPER LEVELS EARLY THIS MORNING...WATER
VAPOR SATELLITE IMAGERY AND SHORT TERM MODEL DATA REVEAL AN
EXPANSIVE...POSITIVELY-TILTED TROUGH DOMINATING MUCH OF THE
CONUS...WITH THE AXIS OF THIS TROUGH EXTENDING FROM MANITOBA
THROUGH WYOMING AND SOUTHWEST TO A SHORTWAVE TROUGH IN THE BASE OF
THE PARENT TROUGH NEAR THE 4-CORNERS. ANOTHER EMBEDDED SHORTWAVE
WAS DROPPING SOUTHEAST ACROSS THE DAKOTAS INTO MN...WHILE ON THE
SOUTHEAST SIDE OF THE PARENT TROUGH...A NARROW BUT INTENSE 150+KT
JET STREAK EVIDENT AT 300MB ALIGNED ALONG A SOUTHWEST-NORTHEAST
AXIS FROM SOUTHWEST KS INTO THE GREAT LAKES. THE SHORTWAVE TROUGH
RESPONSIBLE FOR THE SNOW THAT FINALLY DEPARTED THE CWA SUNDAY
EVENING HAD ALREADY ZIPPED WELL OFF INTO THE WI/MI AREA. IN ITS
WAKE...PRE-DAWN SKIES WERE NEARLY CLOUD-FREE OVER MOST OF THE
CWA...WITH ONLY THE FAR NORTHERN EDGES OF SOME WISPY CIRRUS
BRUSHING MAINLY SOUTHERN ZONES. AT THE SURFACE...09Z OBJECTIVE
ANALYSIS HIGHLIGHTED A 1028MB RIDGE AXIS CENTERED OVER THE
NORTHWEST KS/WESTERN NEB AREA...WITH THE FAIRLY WEAK GRADIENT
BETWEEN THIS HIGH AND A GREAT LAKES LOW HELPING DRIVE SUSTAINED
WEST-NORTHWEST BREEZES ROUGHLY 10 MPH ACROSS MOST OF THE CWA.
DESPITE THESE FAIRLY LIGHT BREEZES...EARLY MORNING WIND CHILLS
HAVE BEEN DRIVEN DOWN INTO AT LEAST THE -15 TO -20 RANGE ACROSS
NEARLY THE ENTIRE CWA...WITH SEVERAL AREAS FLIRTING WITH OR
SLIGHTLY EXCEEDING THE -20 ADVISORY CRITERIA. AS FOR ACTUAL AIR
TEMPERATURES...MOST OF THE CWA HAS ALREADY HIT...OR IS EXPECTED TO
EVENTUALLY REACH LOWS SOMEWHERE BETWEEN ZERO AND -8.

TURNING TO THE FORECAST AND STARTING WITH EARLY THIS
MORNING...BASED ON THE LATEST OBS SHOWING AT LEAST A SCATTERED
COVERAGE OF SUB-20 BELOW ZERO WIND CHILLS NOT ONLY IN NEB ZONES
BUT ALSO DOWN INTO KS ZONES...WILL BE EXPANDING THE PREVIOUSLY-
ISSUED HEADLINE TO THE ENTIRE CWA...BUT KEEPING THE SAME
EXPIRATION TIME OF 10 AM.

IN THE BIG PICTURE ALOFT TODAY...THE AFOREMENTIONED LARGE SCALE
POSITIVE-TILT TROUGH AXIS WILL GRADUALLY SINK SOUTHEASTWARD OVER
THE CENTRAL PLAINS...AND BY SUNSET THIS TROUGH AXIS WILL BE
CENTERED FROM ONTARIO...SOUTHWESTWARD ACROSS IA...NORTH
CENTRAL/WESTERN KS...TO THE TX PANHANDLE. MEANWHILE...A SMALLER
SCALE SHORTWAVE WILL ROTATE AROUND THE PARENT LARGE SCALE HUDSON
BAY VORTEX WELL TO THE NORTH...AND DROP SOUTHEAST INTO THE DAKOTAS
BY SUNSET. AS THE LARGER TROUGH AXIS GRADUALLY SINKS SOUTHEAST
ACROSS THE AREA TODAY...THIS WILL ALSO SHUNT THE AFOREMENTIONED
STOUT UPPER JET STREAK SOUTHEASTWARD WITH IT. HOWEVER...WITH THE
ENTRANCE REGION OF THIS JET LURKING VERY NEAR THE CWA THROUGH AT
LEAST THE FIRST HALF OF THE DAY...MODELS SUCH AS THE 06Z NAM
DEPICT THE DEVELOPMENT OF AN EAST-WEST RIBBON OF MID LEVEL CLOUDS
SLIDING EASTWARD ACROSS MAINLY KS ZONES TODAY...RESULTING IN A
PERIOD OF AT LEAST PARTLY CLOUDY IF NOT MOSTLY CLOUDY
SKIES...WHILE FARTHER NORTH...NO WORSE THAN MOSTLY SUNNY SKIES
SHOULD PREVAIL OVER MOST NEB ZONES. HINTS OF THESE MID CLOUDS ARE
ALREADY UNDERWAY ON 11-3.9 MICRON SATELLITE IMAGERY OVER NORTHWEST
KS. HOWEVER...EVEN AREAS THAT DO CLOUD UP FOR A TIME TODAY SHOULD
RETURN TO NO WORSE THAN MOSTLY SUNNY STATUS BY MID-LATE AFTERNOON
AS THESE CLOUD DEPART EASTWARD. AM NOT EXPECTING EVEN SO MUCH AS
FLURRIES UNDER THESE SOUTHERN-ZONE MID CLOUDS TODAY...AS THE
NEAREST WINTRY PRECIP IS EXPECTED TO FALL NO CLOSER THAN THE KS/OK
BORDER AREA. AT THE SURFACE TODAY...THE AFOREMENTIONED WESTERN
KS/NEB RIDGE AXIS WILL GRADUALLY SLIDE SOUTHEAST OF THE CWA TODAY.
THIS PROGRESSION...ALONG WITH LOW PRESSURE DEVELOPING INTO THE
DAKOTAS...WILL RESULT IN THE GRADUAL TRANSITION FROM WEST-
NORTHWEST BREEZES THIS MORNING...TO SOUTHWESTERLY BREEZES THIS
AFTERNOON...WITH SUSTAINED SPEEDS EVEN PICKING UP TO AROUND 15 MPH
WITH SLIGHTLY HIGHER GUSTS WITHIN THE NORTHWEST 1/2 OF THE
CWA...AND SPEEDS MORE SO 5-10 MPH IN THE SOUTHEAST. TEMP-
WISE...ALTHOUGH THIS SOUTHWESTERLY FLOW WILL USHER IN A VERY
SLIGHTLY WARMER AIRMASS EVIDENT OFF THE SURFACE AT 850MB...TODAY
WILL ALSO MARK THE FIRST TEST OF JUST HOW EFFICIENTLY THE FRESH
SNOW PACK FOCUSED ACROSS THE SOUTHEAST 1/2 OF THE CWA WILL WORK
AGAINST WARMING...DESPITE PLENTY OF SUN. FOR HIGHS...ENDING UP
LARGELY GOING WITH A BLEND OF THE RAW 00Z NAM TEMPS AND THE LATEST
HOURLY RAP13 TEMPS...WHICH SEEMS TO ACCOUNT SOMEWHAT FOR THE
DEEPER SNOW IN THE SOUTHEAST AND LESS SNOW IN THE WEST/NORTHWEST.
THE NET RESULT IS MUCH OF THE EASTERN 1/2 OF THE CWA ONLY TOPPING
OUT 14-18...WITH WESTERN AREAS MORE SO 18-22...AND WARMEST IN THE
FURNAS/PHILLIPS/ROOKS AREA.

TURNING TO THIS EVENING/TONIGHT...TEMPS REMAIN THE MAIN ISSUE.
IN THE MID/UPPER LEVELS...THE FAIRLY COMPACT BUT VIGOROUS
SHORTWAVE TROUGH THAT STARTS THE EVENING CENTERED OVER ND WILL
TRACK SOUTHEAST TO THE MN/WI BORDER BY NIGHTS END...DRIVEN ALONG
IN THE EXIT REGION OF AN ASSOCIATED 115+KT NORTHWESTERLY UPPER JET
STREAK TRANSLATING EAST OUT OF THE NORTHERN ROCKIES INTO THE
PLAINS. AT THE SURFACE...THE ASSOCIATED LOW PRESSURE CENTER OF
AROUND 1012MB WILL SLIDE ALONG A SIMILAR PATH FROM ND TO WI AS THE
NIGHT WEARS ON. AS ITS SOUTHWESTWARD-TRAILING SURFACE TROUGH AXIS
SLIDES THROUGH THE LOCAL AREA...BREEZES WILL TRANSITION FROM
SOUTHWESTERLY IN THE EVENING TO NEARLY DUE-WESTERLY LATE IN THE
NIGHT. AS THIS OCCURS...A BRIEFLY-ENHANCED PRESSURE GRADIENT WILL
COMBINE WITH LIMITED MIXING UNDER A PASSING WEST-NORTHWESTERLY LOW
LEVEL WIND MAX EVIDENT AT 850MB...TO PROMOTE A PERIOD OF SOMEWHAT
BREEZY CONDITIONS ACROSS MUCH OF THE CWA ESPECIALLY BETWEEN
8PM AND 2AM...WITH SUSTAINED SPEEDS INCREASING TO AROUND 15 MPH
WITH GUSTS TO AROUND 20 MPH. AS FOR CLOUDS...WHILE MOST OF THE
NIGHT SHOULD AVERAGE NO WORSE THAN MOSTLY CLEAR...THE PASSING
SHORTWAVE TROUGH AXIS WILL LIKELY RESULT IN A QUICKLY-PASSING
BATCH OF MID CLOUDS CENTERED A FEW HOURS EITHER SIDE OF MIDNIGHT.
NOT EXPECTING EVEN ANY FLURRIES FROM THESE CLOUDS...AS VARIOUS
MODELS INCLUDING SIMULATED REFLECTIVITY KEEP ANY FLURRIES/LIGHT
SNOW NO CLOSER THAN A SD-NORTHERN IA TRACK. AS FOR
TEMPS...OBVIOUSLY THE ENHANCED BREEZES DURING THE EARLY-MID PART
OF THE NIGHT SHOULD KEEP READINGS FAIRLY STEADY...BUT THEN AS
BREEZES START TO DIMINISH A BIT LATE EXPECT TO SEE A FALL...WHICH
OF COURSE COULD BE ENHANCED OVER AREAS OF GREATER SNOW COVER.
ALTHOUGH CONFIDENCE IS A BIT LOWER THAN USUAL...BLENDED VARIOUS
MODELS/GUIDANCE TO YIELD LOWS SLIGHTLY COLDER THAN PREVIOUS
FORECAST...BUT STILL SEVERAL DEGREES WARMER THAN THOSE THIS
MORNING...WITH MOST OF THE AREA FORECAST TO BOTTOM OUT BETWEEN 4-8
ABOVE ZERO. FORTUNATELY...EVEN WITH THE PERIOD OF STRONGER
BREEZES...OVERNIGHT WIND CHILL VALUES ARE PROGGED TO GO NO LOWER
THAN THE -5 TO -12 RANGE...AND GIVEN THAT THIS IS 5+ DEGREES
WARMER THAN ADVISORY CRITERIA IT DOES NOT WARRANT A MENTION IN THE
HAZARDOUS WEATHER OUTLOOK.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 450 AM CST MON DEC 9 2013

THE BIG STORY IS THAT WE SHOULD SEE A RETURN OF AT LEAST SOME WARMER
DAYS...ALTHOUGH WE WILL ALSO SEE A ROLLER COASTER OF TEMPERATURES
INCLUDING SOME CONTINUED COLD DAYS. THE PRIMARY FORECAST CHALLENGE
WILL BE CENTERED ON THE TEMPERATURE FORECAST AND HOW TO HANDLE THE
SNOW COVER IMPACTS ON TEMPERATURES. AT THIS TIME WE ARE NOT
EXPECTING ANY ADDITIONAL ACCUMULATING SNOWFALL EVENTS THROUGH THE
PERIOD.

TUESDAY AND TUESDAY NIGHT...A SFC LOW WILL BE LOCATED OVER THE
NORTHERN PLAINS WITH A SFC HIGH OVER THE SOUTHERN PLAINS. THIS WILL
RESULT IN WESTERLY TO WEST SOUTHWESTERLY DOWNSLOPING WINDS...WHICH
SHOULD RESULT IN A NICE WARM UP. THE CONCERNS ARE THAT WE WILL START
OUT PRETTY COLD TUESDAY MORNING IN THE SINGLE DIGITS AND IT IS
DIFFICULT TO WARM UP VERY FAST WITH FRESH SNOW COVER. THERE SHOULD
BE A GOOD DEAL OF SUN THROUGH MOST OF THE DAY...BUT WILL ALSO HAVE
TO WATCH OUT FOR INCREASING CLOUDS FROM THE NORTH LATE IN THE DAY.
THE FORECAST HIGHS REFLECT THE EXPECTED COOLING EFFECT OF THE DEEPER
SNOW COVER LOCATED IN A ZONE SOUTH OF HIGHWAY 30 IN NEBRASKA AND
NORTH OF HIGHWAY 36 IN KANSAS. THIS AREA GENERALLY SAW 4 TO 7 INCHES
OF SNOW AND SHOULD BE COLDER ON TUESDAY THAN THE AREAS THAT SAW
NOTICEABLY LESS. THERE COULD BE A FEW FLURRIES TUESDAY NIGHT ACROSS
OUR NORTHERN ZONES AS AN UPPER SHORT WAVE TRACK THROUGH NORTHEAST
NEBRASKA. A SFC COLD FRONT WILL SWEEP SOUTH TUESDAY NIGHT THROUGH
THE ENTIRE FORECAST AREA MAKING FOR A COLDER WEDNESDAY.

WEDNESDAY...THE COLD FRONT TUESDAY NIGHT WILL SUPPLY A REINFORCING
SHOT OF COLD AIR AND MAKE FOR A NOTICEABLY COLDER WEDNESDAY. HAVE
ALSO KNOCKED OFF A FEW DEGREES OVER THE DEEPER SNOW COVERED AREAS.

THURSDAY...SFC WINDS WILL TURN BACK TO SOUTHERLY AS SFC HIGH SLIDES
EAST AND AN UPPER RIDGE WILL BUILD ACROSS THE WESTERN CONUS SENDING
WARMER AIR ALOFT INTO THE HIGH PLAINS. CONSEQUENTLY...EXPECT A QUICK
WARMUP WITH HIGHS FOR MOST AREAS POSSIBLY BACK ABOVE THE FREEZING
MARK. HOWEVER...THE DEEPER SNOW COVERED AREAS WILL LIKELY BE AT
LEAST 5 IF NOT 10 DEGREES COLDER THAN SNOW FREE AREAS.
THEREFORE...HAVE LOWERED HIGHS BELOW ALLBLEND OVER OUR DEEPER SNOW
PACK AREAS...BUT MAY STILL BE TO WARM IN THESE DEEPER SNOW AREAS.

FRIDAY...A WEAK SHORT WAVE WILL TRACK ACROSS THE SOUTHERN PLAINS AND
SHOULD BE SOUTH OF OUR FORECAST AREA. DECIDED TO CARRY THE ALLBLEND
SLIGHT POP FOR OUR FAR SOUTHEASTERN ZONES OF BELOIT TO HEBRON JUST
IN CASE THE SYSTEM WERE TO MOVE A LITTLE FURTHER NORTH. THE COLD AIR
WILL BE LOCKED UP OVER CANADA AGAIN WITH THE MORE PROGRESSIVE FLOW
PATTERN ALLOWING FOR MODERATE PACIFIC AIR FLOW ACROSS MUCH OF THE
COUNTRY. WILL CONTINUE TO PAINT A COOLER STRIPE OF TEMPERATURES OVER
THE DEEPER SNOW COVERED AREAS UNTIL THIS SNOW MELTS. MAY ALSO BE TOO
WARM WITH THE FORECAST OVER THESE DEEPER SNOW COVERED AREAS.

SATURDAY AND SUNDAY...UNCERTAINTY IN TEMPERATURE FORECAST IS HIGH.
BOTH THE 00Z GFS AND 00Z ECMWF BRING IN COLDER AIR ON SATURDAY WITH
SOME NORTH WINDS. HOWEVER...THE 00Z GFS IS MUCH QUICKER TO MODERATE
THIS AIRMASS ON SUNDAY AS IT INDICATES MORE OF A GLANCING BLOW OF
COLD AIR. THE ECMWF IS MUCH COLDER ON SUNDAY. THE CURRENT ALLBLEND
FORECAST DOES NOT YET REFLECT THIS NEWER COLDER VERSION OF THE
ECMWF. THEREFORE...OUR HIGHS ON SUNDAY SHOW A NICE WARM UP...BUT
THESE SUNDAY TEMPERATURES COULD EASILY BE SLASHED BY 20 TO 25
DEGREES IF THE NEW ECMWF WERE TO VERIFY. EITHER WAY IT LOOKS LIKE
CONTINUED DRY CONDITIONS.

&&

.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z TUESDAY MORNING)
ISSUED AT 553 AM CST MON DEC 9 2013

THE NEXT 24 HOURS FEATURES A HIGH CONFIDENCE IN VFR
CEILING/VISIBILITY...AND IN FACT THERE WILL BE VERY LIMITED CLOUD
COVER AT ALL...AND ANY OF THE MID-HIGH VARIETY. AS FOR SURFACE
WINDS...SPEEDS THROUGH THE DAY WILL ONLY AVERAGE AROUND 10KT AS
DIRECTION TRANSITIONS FROM WESTERLY TO SOUTHWESTERLY. THEN THIS
EVENING...SOUTHWEST BREEZES WILL PICK UP A BIT WITH GUSTS
INCREASING TO AROUND 20KT IN RESPONSE TO LOW PRESSURE PASSING BY
TO THE NORTH. AFTER MIDNIGHT...THESE SPEEDS WILL SLOWLY DECREASE
AS DIRECTION AGAIN TRANSITIONS TO MORE TRUE-WESTERLY. AS FOR WINDS
JUST OFF THE SURFACE...MODELS STILL SUGGEST THE POSSIBILITY OF
SOME MARGINAL LOW LEVEL WIND SHEAR MAINLY BETWEEN 03Z-09Z AS WINDS
WITHIN THE LOWEST 1500 FT AGL INCREASE TO 40-45KT OUT OF THE WEST-
NORTHWEST...BUT GIVEN THIS DOES NOT APPEAR TO BE A HIGHER-END
SHEAR EVENT...AND THAT IT IS STILL 12+ HOURS AWAY...WILL HOLD OFF
ON A FORMAL TAF MENTION AND DEFER TO NEXT FEW FORECASTERS TO
MONITOR LATEST TRENDS.


&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.

&&

$$

UPDATE...FAY
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...PFANNKUCH