Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 171812
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1212 PM CST WED DEC 17 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM CST WED DEC 17 2014

ONLY A FEW DAYS AFTER THE LAST TRICKY/HIGHLY VARIABLE SNOW EVENT
PAID A VISIT TO THE LOCAL AREA...ANOTHER LOW-CONFIDENCE EVENT FOR
THIS EVENING INTO THURSDAY MORNING HAS BECOME THE MAIN FOCUS OF
THESE NEXT 24 HOURS. GETTING RIGHT TO THE MAIN POINT: ALTHOUGH
MOST ALL OF THE CWA IS EXPECTED TO RECEIVE AT LEAST A VERY LIGHT
DUSTING...THE OVERALL- HIGHEST POTENTIAL FOR AMOUNTS AROUND 2
INCHES SHOULD FOCUS WITHIN NORTH CENTRAL KS ZONES...AND ALTHOUGH
IT IS BY NO MEANS A "SLAM DUNK" VERSUS LOCAL ADVISORY
CRITERIA...THERE WERE ENOUGH PROS VS. CONS TO JOIN NEIGHBORING
WFO/S TOP/ICT ON A WINTER WEATHER ADVISORY FOR
OSBORNE/MITCHELL/JEWELL COUNTIES AS A STARTING POINT...WITH DAY
SHIFT OBVIOUSLY GETTING ANOTHER LOOK TO SEE IF OTHER COUNTIES
MIGHT BE WARRANTED. FORTUNATELY...BARRING ANY SURPRISES FROM
POTENTIAL MESOSCALE BANDING...THIS IS LOOKING LIKE A FAIRLY "LOW-
END" ADVISORY EVENT ESPECIALLY CONSIDERING WIND IS NOT EXPECTED TO
BE A MAJOR ISSUE WITH SPEEDS GENERALLY AVERAGING 10 MPH OR LESS.
ONE WILD CARD FACTOR THAT IS VERY UNCERTAIN IS WHETHER OR NOT AT
LEAST A BRIEF PERIOD OF LIGHT FREEZING DRIZZLE COULD ALSO OCCUR
ALMOST ANYWHERE WITHIN THE CWA TONIGHT...WHICH OF COURSE COULD
RESULT IN A FEW SLICK SPOTS...BUT WITH CONFIDENCE IN FREEZING
DRIZZLE DEVELOPMENT ON THE LOW SIDE AND SNOW AMOUNTS ACROSS THE
VAST MAJORITY OF THE CWA ONLY FORECAST TO AVERAGE 0.5-1.5
INCHES...HAD NO JUSTIFIABLE REASON TO PUT ANY OTHER COUNTIES IN AN
ADVISORY AT THIS TIME.

STARTING OFF THIS MORNING AS OF 1030Z/430 AM...ALL IS QUIET ACROSS
THE CWA...AS ALTHOUGH RADAR HAS INDICATED SOME SUGGESTION OF A FEW
FLURRIES POSSIBLY MAKING IT TO THE GROUND IN NORTHERN
COUNTIES...THERE HAS BEEN NO GROUND-TRUTH THUS FAR TO SUGGEST IT
IS OVERCOMING DRY LOW-MID LEVELS TO REACH THE SURFACE. IN
ADDITION...ALTHOUGH A VERY STUBBORN LOW STRATUS DECK CONTINUES TO
BLANKET MOST ALL OF THE CWA AND HAS EVEN EXPANDED MORE SO INTO
SOUTHERN COUNTIES OF LATE...THERE IS NO EVIDENCE OF LEGITIMATE FOG
FORMATION AND THUS THE PREVIOUS MENTION OF PATCHY FOG IN WESTERN
ZONES FOR THIS MORNING HAS BEEN PULLED WITH THE WIDESPREAD CLOUDS
LIKELY INHIBITING ITS DEVELOPMENT. IN THE MID-UPPER LEVELS...WATER
VAPOR IMAGERY AND SHORT TERM MODEL DATA DEPICT QUASI-ZONAL FLOW
JUST STARTING TO TURN MORE SOUTHWESTERLY IN RESPONSE TO THE
APPROACH OF A COMPLEX/MULTI-FACETED LARGE-SCALE TROUGH WHOSE
FIRST MAIN SHORTWAVE OF INTEREST IS CURRENTLY CENTERED OVER THE
AZ/NM BORDER AREA. CLOSER TO HOME...A VERY WEAK LEAD WAVE AND SOME
UPPER JET ENTRANCE DYNAMICS IS PRODUCING THE NARROW BANDS OF
"WANNABE FLURRIES" OVER NEB AT THIS TIME. AT THE SURFACE...A RIDGE
AXIS CENTERED FROM THE EASTERN DAKOTAS NORTHWARD INTO CANADA HAS
SLID JUST FAR ENOUGH EAST TO ALLOW LOCAL BREEZES TO TRANSITION
FROM NORTHERLY TO EASTERLY...AT SPEEDS GENERALLY WELL UNDER 10
MPH. YET AGAIN...WIDESPREAD CLOUDS HAVE HELPED HOLD TEMPS WELL-
ABOVE THEIR MAX COOLING POTENTIAL...WITH MOST OF THE CWA LOOKING
TO BOTTOM OUT NO COLDER THAN 17-20.

TURNING TO THE FORECAST AND STARTING WITH THE DAYLIGHT HOURS...THE
MAIN POINT TO MAKE IS THAT THE VAST MAJORITY OF THE CWA SHOULD
CONTINUE SEEING MOSTLY CLOUDY TO CLOUDY BUT DRY WEATHER...WITH THE
POSSIBLE EXCEPTION OF SOME WINTRY PRECIP JUST STARTING TO BREAK
OUT IN SOUTHERN KS ZONES LATE IN THE AFTERNOON. IN THE MID-UPPER
LEVELS...THE AFOREMENTIONED SOUTHWESTERN CONUS TROUGH WILL MAKE
ITS WAY EAST-NORTHEAST INTO THE CENTRAL/SOUTHERN PLAINS WITH TIME.
HOWEVER...PART OF THE REASON THIS 24-HOUR PRECIP FORECAST IS LOW-
CONFIDENCE IS THAT THIS TROUGH IS LOOKING TO COME OUT IN SMALLER
PIECES...AND POSSIBLY BE PRONE TO AT LEAST LIMITED MESOSCALE
BANDING AS WELL...WHICH CAN BE ALMOST IMPOSSIBLE TO NAIL DOWN
UNTIL IT ACTUALLY SHOWS ITS HAND. AT THE SURFACE TODAY...HIGH
PRESSURE TO THE NORTHEAST AND WEAK LOW PRESSURE TO THE SOUTHWEST
WILL KEEP EASTERLY BREEZES IN PLACE...AT SUSTAINED SPEEDS NO MORE
THAN 10-15 MPH. CLOUD-WISE TODAY...WHILE THE COVERAGE OF MID-UPPER
CLOUDS MAY WANE FOR A TIME TODAY...THE LATEST RAP/NAM LOW LEVEL
RELATIVE HUMIDITY PROGS SUGGEST THAT LOW STRATUS SHOULD AGAIN HANG
TOUGH ACROSS THE VAST MAJORITY OF THE CWA PROVIDING ANOTHER GLOOMY
DAY. SUPPOSE THERE IS SOME CHANCE THAT EASTERN ZONES COULD SEE
SOME CLEARING PUSH IN FROM THE EAST THIS AFTERNOON...BUT THE
OFFICIAL FORECAST STAYS ON THE PESSIMISTIC SIDE GIVEN RECENT
TRENDS. PRECIP-WISE...UNLESS A ROGUE FLURRY MAKES IT TO THE GROUND
THROUGH EARLY-MID AFTERNOON...IT SHOULD STAY PRECIP-FREE UNTIL AT
LEAST LATE AFTERNOON. HOWEVER...DID START A SLIGHT CHANCE OF
SNOW/FLURRIES MAINLY WITHIN THE SOUTHERN-MOST 3 KS COUNTIES LATE
IN THE AFTERNOON JUST IN CASE A FEW OF THE FASTER-TO-SATURATE
MODELS SUCH AS THE 4KM WRF/NMM HAPPEN TO BE ONTO
SOMETHING...ALTHOUGH DETERMINISTIC NAM/GFS SUGGEST THE ENTIRE CWA
REMAINS PRECIP-FREE THROUGH SUNSET. TEMP-WISE...LIKE YESTERDAY
EXPECTING LITTLE RISE THROUGH THE DAY...AND ALTHOUGH MAY STILL BE
A TOUCH TOO WARM IN SOME SPOTS...LOWERED PREVIOUS FORECAST
GENERALLY 1-2 DEGREES TO YIELD GENERALLY 26-31 ACROSS MOST NEB
ZONES...AND 30-35 IN KS.

FOR THIS EVENING/TONIGHT...ALREADY COVERED SOME OF THE REASONING
BEHIND HEADLINES AND CONSIDERABLE UNCERTAINTY OF THIS
PRECIPITATION EVENT IN PRECEDING PARAGRAPHS...BUT THE VERY
GENERAL EXPECTATION IS FOR PRECIPITATION TO SPREAD INTO THE CWA
FROM THE SOUTH AND/OR BREAK OUT OVERHEAD AS THE MULTI-FACETED
SHORTWAVE TROUGH SLIDES EAST ACROSS NEB/KS...WITH THE MAJORITY OF
ACCUMULATING SNOW FALLING DURING THE 9PM-3AM WINDOW. HIGHER-RES
MODELS SUCH AS THE 4KM WRF NMM/ARW AND EVEN THE NAM CLEARLY
SUGGEST THERE COULD BE JUST ENOUGH INSTABILITY TO PROMOTE
MESOSCALE BANDING...POTENTIALLY EVEN FARTHER NORTH TOWARD THE
INTERSTATE 80 CORRIDOR. HOWEVER...DESPITE THE CONSIDERABLE
UNCERTAINTY IN EXACTLY HOW THIS PLAYS OUT...MODEL CONSENSUS
DEFINITELY SUGGESTS THE OVERALL HIGHEST QPF/SNOW AMOUNTS SHOULD
FOCUS WITHIN ROUGHLY THE SOUTHERN/SOUTHEAST 1/3 OF THE CWA...WHERE
GENERAL AMOUNTS OF 1-2 INCHES ARE MOST FAVORED...WHILE AREAS
ROUGHLY NORTHWEST OF AN ALMA-HASTINGS-YORK LINE (INCLUDING THE
TRI-CITIES) SHOULD GENERALLY FALL SHORT OF 1 INCH...WITH FAR
NORTHWESTERN COUNTIES SUCH AS DAWSON/VALLEY/GREELEY POTENTIALLY
HARDLY SEEING ANY SNOW AT ALL. FURTHER COMPLICATING THINGS EVEN AT
THIS SHORT TIME RANGE IS THE SUGGESTION THAT DENDRITIC LAYER /MID-
LEVEL SATURATION MAY BE SKETCHY AT TIMES ESPECIALLY OUTSIDE THE
MAIN SNOW AREA...WHICH GIVEN THE LIFT FROM THE PASSING WAVE COULD
PROMOTE AT LEAST LIMITED LIGHT FREEZING DRIZZLE ALMOST ANYWHERE
ACROSS THE AREA...AND THUS THIS HAS EITHER BEEN INTRODUCED OR
MAINTAINED IN THE FORECAST CWA-WIDE FROM LATE THIS EVENING INTO
THURS MORNING. BY AND LARGE THOUGH...IN THEORY THIS SHOULD MAINLY
BE A SNOW EVENT AND NOT A FREEZING DRIZZLE EVENT.
FORTUNATELY...WINDS WILL CONTINUE TO NOT BE A BIG DEAL THROUGH THE
NIGHT...AS EAST-SOUTHEAST SPEEDS CONTINUE TO AVERAGE ONLY 5-10
MPH. LOW TEMPS WERE CHANGED VERY LITTLE IF ANY FROM PREVIOUS
FORECAST...AIMED INTO THE 19-26 RANGE ACROSS MUCH OF THE CWA...OR
GENERALLY 2-4 DEGREES ABOVE A 00Z MET/MAV GUIDANCE BLEND WHICH
AGAIN APPEARS TOO COLD GIVEN THE WIDESPREAD CLOUDS.

IN CLOSING...ALTHOUGH POINT/COUNTY-SPECIFIC SNOWFALL FORECASTS
SHOULD NEVER BE TAKEN "LITERALLY"...SETUPS SUCH AS THIS ARE EVEN
MORE SO THE CASE...AS ALTHOUGH NOBODY IS CURRENTLY EXPECTED TO
EXCEED 1 OR 2 INCHES...THERE WILL UNDOUBTEDLY BE THOSE PLACES
THAT HARDLY SEE A SNOWFLAKE...WHILE IN CONTRAST ITS POSSIBLE THAT
CONCENTRATED BANDING COULD PUSH A FEW SOUTHEASTERN LOCATIONS
CLOSER TO 3 INCHES.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 441 AM CST WED DEC 17 2014

THE BIGGEST CHALLENGE WILL BE DETERMINING PRECIPITATION TYPE AND
CHANCE OF PRECIPITATION THURSDAY AND THURSDAY NIGHT.

THURSDAY MORNING WILL BE A BIT DIFFICULT AS THE LAST REMAINING
PRECIPITATION HEADS OUT OF THE CWA WITH THE THE TROUGH AXIS
CONTINUING TO HEAD TO THE EAST. THE PROBLEM IS THAT WE BEGIN LOSING
THE SATURATED DENDRITIC GROWTH ZONE BEFORE LIFT ENDS. THIS WILL GIVE
US A SHOT AT SOME FREEZING DRIZZLE THURSDAY MORNING. THERE SHOULD BE
ENOUGH SUBSIDENCE THURSDAY AFTERNOON AND EARLY EVENING TO KEEP
PRECIPITATION OUT OF THE FORECAST...SO I TOOK FLURRIES OUT OF THE
AFTERNOON...BUT THE NEXT QUANDARY WILL BE THURSDAY NIGHT.

ANOTHER PIECE OF LOW-AMPLITUDE WAVE APPROACHES THURSDAY NIGHT...AND
THE PROBLEM IS THAT THERE IS DECENT AGREEMENT AMONG NUMERICAL MODELS
THAT THERE WILL BE A LACK OF MOISTURE IN WHAT WOULD BE THE DENDRITIC
GROWTH ZONE. THE LOWER LEVELS WILL BE SATURATED NEAR THE
SURFACE...AND THIS LOOKS DEEP ENOUGH THAT THIS COULD BE TROUBLE. THE
VEERING WIND PROFILES SUPPORTS THE PRODUCTION OF SOME FREEZING
DRIZZLE...AND THE NAM ADVERTISES WIDELY SCATTERED SPOTS OF LOW QPF.
LOOKS LIKE A SHORT-LIVED EVENT AS THE TROUGH AXIS MOVES QUICKLY
ALONG. IF ANY FREEZING DRIZZLE OCCURS...IT WILL PROBABLY BE ONLY A
FEW HOURS.

00Z RUNS OF NUMERICAL MODELS PLACE THE TROUGH AXIS EAST OF THE CWA
BY FRIDAY...BUT TRENDS IN 06Z MODELS SEEM TO BE SLOWER...WHICH MIGHT
MAKE FRIDAY MORNING QUESTIONABLE. HOWEVER...THE ALREADY LOW QPF IS
TRENDING LESS...SO NOT MUCH AT ALL MAY HAPPEN. CONFIDENCE IS LOW AS
FORECASTING IS DIFFICULT IN SITUATIONS OF PROGRESSIVE FLOW AND LOW-
AMPLITUDE WAVES/PERTURBATIONS.

KEPT A MOSTLY DRY FORECAST BEYOND THURSDAY NIGHT THROUGH THE WEEKEND
AND INTO THE EARLY WORK WEEK...WITH SOME LOW CHANCES OF
PRECIPITATION ON THE FRINGES OF THE CWA SUNDAY NIGHT INTO MONDAY
NIGHT. MODELS ARE STARTING TO CONVERGE ON SOME TROUGHY LOOK TO THE
UPPER PATTERN OVER THE PLAINS BY EARLY NEXT WORK WEEK...SO WE COULD
BE IN FOR AN INCREASE IN CHANCES OF PRECIPITATION EARLY NEXT WORK
WEEK...DEPENDING ON TRENDS OF NUMERICAL MODELS. TEMPERATURES SLOWLY
MODERATE INTO THE WEEKEND WITH HIGHS IN THE 40S THROUGHOUT THE CWA
BY SUNDAY. WE COULD BE IN FOR A LITTLE RAIN OR SNOW EARLY NEXT WORK
WEEK...WITH PRECIPITATION TYPE DEPENDING ON TEMPERATURES. HOW GREAT
THE CHANCES OF PRECIPITATION ARE DEPENDS ON THE TROUGH STAYING
AROUND LONG ENOUGH AND ESSENTIALLY FAR ENOUGH WEST TO GIVE US
ANOTHER DECENT CHANCE OF PRECIPITATION. MORE AGREEMENT AMONG
NUMERICAL MODELS WILL BE NEEDED TO INCREASE CHANCES OF PRECIPITATION.

&&

.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1206 PM CST WED DEC 17 2014

GENERALLY POOR CONDITIONS WILL PERSIST AT BOTH TERMINALS FOR THE
NEXT 24 HOURS AS AMPLE LOW LEVEL STRATUS...SOME BR...AND POSSIBLY
EVEN A FEW HOURS OF LIGHT SNOW...WILL BE POSSIBLE DURING THE VALID
PERIOD. THIS AFTERNOON...EXPECT LOW LEVEL STRATUS AND SOME BR TO
CONTINUE TO PERSIST AT THE TERMINALS FOR THE NEXT FEW
HOURS...WITH SOME SLIGHT IMPROVEMENT POSSIBLE AFT ABOUT 17/22Z.
THEREAFTER...EXPECT AN APPROACHING DISTURBANCE EMERGING INTO THE
PLAINS TO SPREAD SOME VERY LIGHT SNOW AND LOWER CIGS ACROSS THE
REGION DURING THE OVERNIGHT HOURS...WITH THE BEST CHANCE FOR ANY
LIGHT SNOW COMING BETWEEN ABOUT MIDNIGHT AND 6 AM AT BOTH SITES.
THEREAFTER...CIGS MAY ACTUALLY LOWER AND VISIBILITIES DROP
FURTHER...AS THERE ARE SOME INDICATIONS THAT BR WILL PERSIST
THROUGH AT LEAST THE EARLY AFTERNOON HOURS THURSDAY. WHILE
GENERALLY IFR TO LIFR CONDITIONS ARE FORECAST THROUGH THE
PERIOD...THE GOOD NEWS IS THAT THE WINDS WILL BE FAIRLY
LIGHT...MAINLY SOUTHEASTERLY AT LESS THAN 10 KTS THROUGH THE
PERIOD.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST
     THURSDAY FOR KSZ007-018-019.

&&

$$

SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...ROSSI



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