Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 281127
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
527 AM CST SAT FEB 28 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 342 AM CST SAT FEB 28 2015

MAP ANALYSIS INDICATES QUASI-ZONAL UPPER TROPOSPHERIC FLOW
PERSISTING OVER THE CENTRAL CONUS. AN UPPER TROPOSPHERIC SHORT
WAVE IS ALSO NOTED OVER PORTIONS OF SOUTH-CENTRAL CANADA. ENHANCED
UPPER TROPOSPHERIC FLOW EXTENDS FROM THE SOUTHWESTERN CONUS...EAST
INTO THE SOUTHERN PLAINS AND THEN EAST/NORTHEAST INTO THE MID-
ATLANTIC. UPPER TROPOSPHERIC FLOW OVER OUR AREA REMAINS FAIRLY
WEAK...ONLY MAXING OUT AT AROUND 40KTS NEAR 28000FT AGL. AT THE
SURFACE...AN AREA OF HIGH BAROMETRIC PRESSURE IS NOTED OVER THE
MID MISSISSIPPI VALLEY AND AS A RESULT...THE BOUNDARY-LAYER WIND
FIELD ACROSS OUR AREA REMAINS FROM THE SOUTH/SOUTHEAST.

GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST THE
UPPER TROPOSPHERIC SHORT WAVE...CURRENTLY OVER SOUTH-CENTRAL
CANADA...WILL MOVE SOUTHEAST THROUGH THE NEXT 36 HOURS.
MEANWHILE...ANOTHER UPPER TROPOSPHERIC TROUGH AXIS IS EXPECTED TO
STRENGTHEN OVER THE SOUTHWESTERN CONUS. AS A RESULT...UPPER
TROPOSPHERIC FLOW OVER OUR AREA SHOULD REMAIN QUASI-ZONAL THROUGH
THE NEXT 36 HOURS. AT THE SURFACE...THE AREA OF HIGH BAROMETRIC
PRESSURE OVER THE MID MISSISSIPPI VALLEY IS EXPECTED TO MOVE EAST
DURING THE SHORT-TERM FORECAST PERIOD...THUS ALLOWING FOR
CONTINUED SOUTH/SOUTHEASTERLY BOUNDARY-LAYER FLOW TODAY. THE
MOVEMENT OF THE AFOREMENTIONED UPPER TROPOSPHERIC SHORT WAVE
SHOULD HELP PROMOTE AN AREA OF LOW BAROMETRIC PRESSURE OVER
SOUTHERN CANADA AND THE GREAT LAKES REGION BY TONIGHT
HOWEVER...THUS ALLOWING FOR THE PASSAGE OF A SURFACE TROUGH ACROSS
OUR AREA SUNDAY MORNING. NORTHWESTERLY BOUNDARY-LAYER FLOW IS THEN
EXPECTED ACROSS OUR AREA DURING THE DAY SUNDAY.

GUIDANCE CONTINUES TO SUGGEST UPPER TROPOSPHERIC THERMAL
ADVECTION AND RESULTANT OMEGA...ALONG WITH POCKETS OF ENHANCED
UPPER TROPOSPHERIC JET DYNAMICS...WILL PROMOTE PRECIPITATION
PRODUCTION ACROSS PORTIONS OF THE REGION TODAY IN TO THIS EVENING.
THAT SAID...IT CONTINUES TO LOOK MORE LIKELY THAT THE PRIMARY AXIS
OF OMEGA WILL REMAIN TO OUR SOUTH/SOUTHEAST...MORE OVER SOUTHERN
AND EASTERN KANSAS. ALTHOUGH PRECIPITATION PRODUCTION REMAINS
POSSIBLE ACROSS OUR CWA TODAY INTO THIS EVENING...ESPECIALLY
ACROSS OUR SOUTHEAST IN CLOSEST PROXIMITY TO THE PRIMARY AXIS OF
OMEGA...MODEL GUIDANCE CONTINUES TO DOWNPLAY PRECIPITATION RATES
ACROSS MOST ALL OF OUR CWA. STILL...POPS REMAIN INTACT ACROSS
PORTIONS OF THE AREA TODAY THROUGH THIS EVENING FOR THE POTENTIAL
FOR LIGHT PRECIPITATION. GUIDANCE THEN SUGGESTS THE PRIMARY AXIS
OF OMEGA WILL MAKE A SWIFT PUSH TO THE SOUTHEAST THIS
EVENING...THUS PROVIDING A DRY PERIOD ACROSS OUR AREA THIS EVENING
INTO THE EARLY MORNING HOURS SUNDAY. ALTHOUGH THERE ARE NOW NO
REAL INDICATIONS THAT THIS PRIMARY AXIS OF OMEGA WILL MAKE A PUSH
BACK TO THE NORTHWEST ON SUNDAY...AS WAS BEING INDICATED 24 HOURS
AGO...IT DOES NOW APPEAR THAT THE RIGHT-REAR QUADRANT OF AN ~130KT
UPPER TROPOSPHERIC JET STREAK WILL NEAR OUR AREA SUNDAY
MORNING...THUS PROMOTING ANOTHER ROUND OF PRECIPITATION ACROSS
MUCH OF OUR CWA THROUGH ABOUT MIDDAY SUNDAY. GIVEN ALL THIS...WENT
AHEAD AND CONTINUED POPS ACROSS MUCH OF THE CWA 06-18Z SUNDAY.

FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE
NAM...OPERATIONAL GFS AND EC...ALL SUGGEST A PERSISTENTLY COLD AIR
MASS WILL CONTINUE TO PROMOTE SNOW AS THE PRIMARY PRECIPITATION
TYPE THROUGH THE DAY SUNDAY...AND SUCH HAS BEEN PRESENTED IN THE
OFFICIAL FORECAST. IN ADDITION...A BLEND OF THE NAM AND
OPERATIONAL GFS SUGGEST SNOW-WATER RATIOS OF 15-20:1 WILL BE
OBSERVED...A CONSISTENT SIGNAL FROM MODEL GUIDANCE THROUGH PAST
FEW DAYS.

TAKING A BLEND OF THE NAM...OPERATIONAL GFS AND EC PROVIDES
LIQUID PRECIPITATION AMOUNTS OF 0.01-0.03" ACROSS OUR NEBRASKA
COUNTIES MAINLY SOUTH OF I-80...AND 0.03-0.05" ACROSS OUR KANSAS
COUNTIES DURING THE DAY TODAY. THIS SAME BLEND OF MODEL GUIDANCE
THEN PROVIDES ~0.01-0.04" OF ADDITIONAL LIQUID PRECIPITATION
ACROSS THE AREA TONIGHT...WITH THE GREATEST PRECIPITATION RATES
BEING REALIZED ACROSS OUR KANSAS COUNTIES. TAKING THESE LIQUID
PRECIPITATION AMOUNTS...ALONG WITH THE AFOREMENTIONED SNOW-WATER
RATIOS...PROVIDES ~0.5" OF SNOWFALL ACROSS MUCH OF THE CWA
TODAY...WITH LOCATIONS ACROSS OUR SOUTH/SOUTHEAST CLOSER TO AN
INCH. BETWEEN A COUPLE TENTHS AND ~1 INCH THEN APPEARS POSSIBLE
TONIGHT THROUGH THE DAY SUNDAY...THUS PROVIDING TOTAL SNOW
ACCUMULATION THROUGH THE WEEKEND OF NEAR AN INCH ACROSS MUCH OF
THE CWA...WITH CLOSER TO 1.5" ACROSS OUR EXTREME SOUTH/SOUTHEAST.

THIS FORECAST PRESENTS YET ANOTHER DECREASE IN SNOW AMOUNTS FROM
THE PREVIOUS SHIFT...A TREND WHICH HAS BEEN COMMON THROUGH THE
PAST FEW DAYS. SO ALTHOUGH IT REMAINS HIGHLY LIKELY PORTIONS OF
OUR CWA...ESPECIALLY OUR SOUTHEAST...WILL OBSERVE ACCUMULATING
SNOWFALL TODAY THROUGH SUNDAY...THIS DOES NOT APPEAR TO BE A
SIGNIFICANT STORM AND THE THREAT FOR "HIGH-IMPACT" WEATHER APPEARS
VERY LOW. ESPECIALLY WHEN ONE CONSIDERS THE FACT THAT THE
BOUNDARY-LAYER WIND FIELD SHOULD REMAIN FAIRLY WEAK
TODAY...~10KTS...AND SHOULD ACTUALLY BECOME LIGHT AND VARIABLE
TONIGHT THUS ELIMINATING ANY CHANCE FOR VISIBILITY RESTRICTION IN
BLOWING SNOW. GIVEN ALL THIS...FINDING IT EXTREMELY HARD TO
JUSTIFY THE CURRENT WINTER WEATHER ADVISORY FOR OSBORNE AND
MITCHELL COUNTIES IN KANSAS. GIVEN THIS...WILL GO AHEAD AND
TERMINATE THE ADVISORY...BUT CONTINUE TO MENTION ACCUMULATING
SNOWFALL IN THE HWO.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 424 AM CST SAT FEB 28 2015

WHILE THE SHORT TERM SECTION ABOVE FOCUSES ON ESSENTIALLY "ROUND
1" OF PRECIP POTENTIAL THIS WEEKEND...THIS SECTION FOCUSES ON
WHAT WE WILL CALL "ROUND 2" NEXT WEEK...WHICH ACTUALLY CONSISTS
OF VARIOUS...STILL FAIRLY-LOW CONFIDENCE CHANCES OF PRECIP DURING
THE LATE SUNDAY NIGHT THROUGH TUESDAY NIGHT TIME FRAME. ALTHOUGH
THERE IS OBVIOUSLY STILL PLENTY OF TIME FOR THINGS TO CHANGE FOR
THE WORSE OR BETTER...AT THIS POINT THIS TIME FRAME IS NOT LOOKING
LIKE A "MAJOR SYSTEM"...BUT INSTEAD MORE OF A NUISANCE LIGHT
PRECIP SITUATION FOR THE MOST PART. IN FACT...NONE OF THESE
PERIODS CURRENTLY FEATURE POPS HIGHER THAN 40-50 PERCENT...AND
MOST PERIODS ONLY 20-30 PERCENT. GIVEN THAT POPS/SNOW AMOUNTS ARE
NOT ANY HIGHER THAN THEY ARE...STILL CANNOT JUSTIFY MENTIONING
THESE PRECIP CHANCES IN THE HAZARDOUS WEATHER OUTLOOK (HWOGID)
PRODUCT YET. ALL THIS BEING SAID...AND NOT WANTING TO DOWNPLAY
THINGS TOO MUCH HERE...THERE ARE AT LEAST TWO ASPECTS OF THIS TIME
FRAME BEAR WATCHING FOR POSSIBLE ISSUES/NEW FORECAST TWISTS:

1) ALTHOUGH HAVE KEPT PRECIP TYPE DURING THIS TIME FRAME AS EITHER
SNOW OR RAIN/SNOW FOR NOW GIVEN IT IS STILL A FEW DAYS OUT
(KEEPING IT SIMPLE)...THERE ARE INCREASING HINTS THAT PRECIP
ESPECIALLY AROUND THE MONDAY NIGHT TIME FRAME MAY SIMPLY BE IN THE
FORM OF DRIZZLE GIVEN A LACK OF SATURATION ALOFT. IF FUTURE
FORECASTS DO HEAD DOWN THIS "DRIZZLE ROAD"...THEN BASED ON LOW
TEMPERATURES CURRENTLY AIMED A FEW DEGREES EITHER SIDE OF
FREEZING...SOME PLACES ESPECIALLY WITHIN THE NORTHERN 1/2 OF THE
CWA COULD RUN THE RISK OF FREEZING DRIZZLE/LIGHT ICING. STAY TUNED
HERE...

2) IF SNOW TRULY DOES BECOME "IMPACTFUL" AT SOME
POINT...PRELIMINARY INDICATIONS ARE THAT THIS WOULD MOST LIKELY
OCCUR DURING THE VERY LATE MONDAY NIGHT INTO TUESDAY DAYTIME
PERIOD...AND PRIMARILY NORTH OF INTERSTATE 80. THIS IS WHERE THERE
SEEMS TO LIE THE BEST POTENTIAL FOR A QUICK 1+ INCH OF SNOW IN THE
PRESENCE OF STRONG NORTH-NORTHWEST WINDS OF AT LEAST 25-30 MPH
WITH HIGHER GUSTS. AGAIN...STAY TUNED AS THIS IS 3+ DAYS AWAY AND
SUBJECT TO PLENTY OF CHANGE.

BEFORE MOVING ON TO OTHER THINGS...IT REMAINS THE CASE THAT THE
ENTIRE WEDNESDAY-FRIDAY TIME FRAME IS VOID OF PRECIP CHANCES...AS
A PATTERN CHANGE TO QUIETER/LESS-COMPLEX AND EVENTUALLY WARMER
WEATHER GETS UNDERWAY.

AS FOR NON-PRECIPITATION ELEMENTS THAT COULD EVENTUALLY WARRANT
INCLUSION IN THE HWO PRODUCT...THERE ARE SEEMINGLY 2 POSSIBLE
CANDIDATES AT THIS TIME:

1) STRONG WIND TUES: ALREADY HINTED AT THIS ABOVE...BUT THERE IS
CERTAINLY SOME POTENTIAL THAT SUSTAINED NORTH WINDS COULD TOP 30
MPH (OUR OLD WIND ADVISORY CRITERIA) ON TUESDAY. THE CURRENT
FORECAST FALLS JUST SHORT OF OFFICIALLY CALLING FOR SPEEDS THIS
STRONG...SO THUS NO HWO MENTION YET.

2) WIND CHILLS TUES NIGHT/WED: LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING...THE CURRENT FORECAST CALLS FOR WIND CHILLS TO DROP TO
-15 OR SLIGHTLY COLDER MAINLY NORTH OF NEB HIGHWAY 92...WHILE MOST
OF THE CWA DROPS INTO THE -5 TO -15 RANGE. WHILE ALL AREAS STILL
REMAIN A FEW DEGREES SHY OF ADVISORY CRITERIA (-20)...THE NEAR-
ADVISORY VALUES MAY NEED HWO INCLUSION AS THIS TIME FRAME DRAWS
CLOSER.

MOVING ON TO A BRIEF TEMPERATURE OVERVIEW...THERE IS DEFINITELY
SOME "LIGHT AT THE END OF THE COLD TUNNEL" FOR MILDER-WEATHER
LOVERS. WHILE HIGHS IN MOST OF THE CWA ARE ONLY FORECAST TO REACH
THE 20S/30S FROM MONDAY-THURSDAY (WITH WEDNESDAY PRETTY CLEARLY
THE COLDEST DAY WITH ONLY LOW-MID 20S AT THIS POINT)...NEXT FRIDAY
IS PRELIMINARILY AIMED INTO THE UPPER-40S/MID-50S RANGE...AND THIS
MAY NOT EVEN BE QUITE WARM ENOUGH ESPECIALLY PER THE LATEST ECMWF
SOLUTION.

LAST BUT NOT LEAST...WILL FINISH AS USUAL BY DIVING INTO GREATER
DETAIL IN 12-48 HOUR BLOCKS:

SUNDAY EVENING/NIGHT: HAVE LEFT THE PRE-MIDNIGHT HOURS VOID OF
PRECIP CHANCES CWA-WIDE...WHILE BRINGING ONLY LOW-END 20-30 POPS
FOR LIGHT SNOW INTO MAINLY THE SOUTHWEST 1/3 OF THE CWA AFTER
MIDNIGHT AS INCREASING SOUTHWESTERLY ISENTROPIC LIFT INCREASES
INTO THE CWA FROM THE SOUTHWEST. THE MAJORITY OF THE CWA HOWEVER
(ESPECIALLY EAST OF HIGHWAY 281) IS EXPECTED TO REMAIN SNOW-FREE
THROUGH THE ENTIRE NIGHT. EVEN IN SOUTHWEST ZONES...AM CURRENTLY
ONLY CALLING FOR UP TO A FEW TENTHS OF AN INCH OF ACCUMULATION. IN
THE LARGE-SCALE ALOFT...THE LOCAL AREA REMAINS IN A MULTI-DAY
STRETCH OF FAIRLY ACTIVE WEST-SOUTHWEST FLOW ALOFT...DOWNSTREAM
FROM A PARENT LARGE-SCALE TROUGH IN THE WESTERN CONUS. AT THE
SURFACE...BREEZES SUNDAY NIGHT WILL AVERAGE NO MORE THAN 5-10
MPH...TURNING FROM NORTHERLY TO SOUTHEASTERLY. MADE HARDLY ANY
CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 16-20.

MONDAY DAYTIME/NIGHT: NEEDLESS TO SAY...CONFIDENCE IN THE DETAILS
AT THIS TIME RANGE IS STILL FAIRLY SHAKY. DESPITE STILL
ADVERTISING MODEST 20-30 POPS CWA-WIDE DURING THESE 24 HOURS...ITS
STARTING TO LOOK MORE LIKE THE VAST MAJORITY OF THE TIME MAY
REMAIN PRECIP-FREE (ESPECIALLY PER THE ECMWF SOLUTION). BEST GUESS
AT THIS POINT IS THAT A BAND OF LIGHT SNOW LIFTS NORTHWARD ACROSS
MAINLY NEB ZONES ON MONDAY MORNING...WITH ONLY A FEW TENTHS OF AN
INCH OF ACCUMULATION. THEN FOLLOWING A POSSIBLE (IF NOT LIKELY)
LULL DURING THE AFTERNOON...THE NIGHT HOURS COULD FEATURE A
COMBINATION OF RAIN AND OR/DRIZZLE...AND MAYBE SOME LIGHT SNOW
ACCUMULATION MAINLY NORTH. GIVEN STEADY SOUTHERLY BREEZES AND
LOW-LEVEL WARM AIR ADVECTION...RAISED HIGHS GENERALLY 2 DEGREES
AND MONDAY NIGHT LOWS MORE-SO 3-4 DEGREES FROM PREVIOUS
FORECAST...AND MAYBE NOT ENOUGH. HIGHS GENERALLY MID-30S AND LOWS
GENERALLY LOW-30S. AT LEAST SLIGHT OVERNIGHT TEMP RISES ARE
CERTAINLY POSSIBLE AS WELL. AS COVERED EARLIER...WILL HAVE TO KEEP
A CLOSE EYE ON FREEZING DRIZZLE POTENTIAL MONDAY NIGHT ESPECIALLY
NORTHERN ZONES...WHILE ANY PRECIP IN SOUTHERN ZONES WOULD LIKELY
JUST BE PLAIN LIQUID NON- FREEZING RAIN/DRIZZLE.

TUESDAY DAYTIME/NIGHT: THESE 24 HOURS FEATURE THE PASSAGE OF WHAT
WILL LIKELY BE A RATHER STOUT SURFACE COLD FRONT...FORCED BY THE
PASSAGE OF THE LARGER-SCALE MID-UPPER LEVEL TROUGH INTO THE
CENTRAL CONUS. AS EARLIER-MENTIONED...MAY HAVE TO WATCH THE
DAYTIME HOURS FOR A BLAST OF WIND-BLOWN ACCUMULATING SNOW
DEPENDING ON HOW ORGANIZED PRECIP IS ABLE TO BE (GFS CURRENTLY
LOOKS MORE OMINOUS THAN THE USUALLY-PREFERRED ECMWF). OF GREATER
CONFIDENCE IS THAT IT WILL BE WINDY FROM THE NORTH BEHIND THE
FRONT...WITH FALLING AFTERNOON TEMPS. PRIOR TO THE FALL
THOUGH...COULD SEE QUITE A GRADIENT IN HIGH TEMPS...CURRENTLY
AIMED FROM ONLY UPPER 20S FAR NORTHWEST...TO 40S SOUTHEAST...WHICH
COULD VERY WELL KEEP ANY EARLY-DAY PRECIP AS LIQUID RAIN IN
SOUTHEAST AREAS. POPS FOR THE DAYTIME ARE AS HIGH AS 50 PERCENT AT
THIS TIME IN NORTHERN/EASTERN ZONES...WITH ONLY A LINGERING 30 POP
FOR LIGHT SNOW TUESDAY NIGHT. AS EARLIER MENTIONED...WIND CHILLS
COULD APPROACH ADVISORY CRITERIA LATE IN THE NIGHT AS ACTUAL LOW
TEMPS FALL INTO THE SINGLE DIGITS ABOVE ZERO MOST AREAS.

WEDNESDAY DAYTIME-THURSDAY NIGHT: CONFIDENCE REMAINS FAIRLY HIGH
AT THIS TIME RANGE IN THESE 48 HOURS REMAINING PRECIP-FREE...AS
THE LARGE-SCALE PATTERN FEATURES THE PASSAGE OF THE PESKY TROUGH
INTO THE EASTERN CONUS...WHICH BRINGS BACK FAIRLY UNEVENTFUL
NORTHWEST FLOW TO THE CENTRAL PLAINS. TEMP-WISE...WEDNESDAY IS
ALMOST ASSUREDLY THE COLDEST DAY OF THE WORK-WEEK WITH HIGHS ONLY
AIMED INTO THE LOW-MID 20S...BEFORE A RETURN TO SOUTHERLY LOW
LEVEL FLOW RESULTS IN A DECENT REBOUND INTO THE MID-30S TO LOW-40S
RANGE FOR THURS.

FRIDAY DAYTIME: ALTHOUGH NEARLY A WEEK OUT...THIS CURRENTLY LOOKS
LIKE A VERY-WELCOMED WARMER DAY AS BOTH THE ECMWF/GFS DEPICT
DOWNSLOPE WESTERLY SURFACE BREEZES. ALTHOUGH HIGHS WERE NUDGED UP
A FEW DEGREES MAINLY INTO THE 47-53 RANGE...WOULD NOT BE SURPRISED
IF THINGS END UP AT LEAST SLIGHTLY WARMER YET.

&&

.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 527 AM CST SAT FEB 28 2015

VFR CONDITIONS TO START AT KGRI...WITH MVFR CONDITIONS EXPECTED
BY 15Z. MVFR CONDITIONS ARE ALREADY BEING OBSERVED AT KEAR...AND
THIS IS EXPECTED TO CONTINUE THROUGH MUCH OF THE TAF PERIOD.

A LOW CEILING NEAR 2000FT AGL IS INFILTRATING THE REGION
NOW...AND WILL LIKELY IMPACT BOTH TAF SITES THROUGH THE NEXT 24
HOURS. THE SURFACE WIND WILL START FROM THE SOUTH/SOUTHEAST AT
10-12KTS TODAY...BUT BECOME LIGHT AND VARIABLE TONIGHT. SNOWFALL
IS STILL EXPECTED TO OVERTAKE PORTIONS OF THE REGION TODAY AND
TONIGHT...BUT AT THIS TIME IT STILL APPEARS THE MAJORITY OF THIS
SNOWFALL WILL STAY SOUTHEAST OF BOTH TAF SITES. AS A
RESULT...CONFIDENCE IS NOT YET HIGH ENOUGH TO INCLUDE PREVAILING
SNOWFALL IN EITHER TAF. VISIBILITY RESTRICTION IS NOT CURRENTLY
EXPECTED AT EITHER TAF SITE THROUGH THE NEXT 24 HOURS.

&&

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

$$

SHORT TERM...BRYANT
LONG TERM...PFANNKUCH
AVIATION...BRYANT


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