Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 042155
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
355 PM CST THU FEB 4 2016

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 331 PM CST THU FEB 4 2016

OVERVIEW...THERE ARE A FEW FORECAST CONCERNS OVER THE NEXT 24
HOURS. FOG IS NOT LIKELY...BUT CAN NOT COMPLETELY RULE IT OUT
ACROSS OUR NORTHEASTERN ZONES THIS EVENING INTO TONIGHT. IN
ADDITION...A VERY LIGHT SNOW EVENT IS POSSIBLE FRIDAY MORNING
PRIMARILY BETWEEN 4 AM AND NOON AND FOCUSED ON NEBRASKA ZONES.
HOWEVER...SNOWFALL AMOUNTS WILL BE VERY LOW IF WE EVEN GET
ANYTHING...GENERALLY LESS THAN ONE HALF INCH IN MOST PLACES.

FOG POTENTIAL...THERE HAS BEEN A LOW STRATUS DECK THIS AFTERNOON
OVER PORTIONS OF NORTHWESTERN IOWA. THE HRRR HAS BEEN FORECASTING
FOG FORMATION THIS EVENING OVER THE THICK SNOW COVER AND NEAR THE
EDGE OF THIS STRATUS DECK ACROSS NORTHEASTERN NEBRASKA. THE SREF
FOG POTENTIAL IS ALSO OVER 50 PERCENT IN SOME OF THIS AREA. IN
ADDITION...THE WIND WILL BE LIGHT AND VARIABLE SUPPORTING FOG.
HOWEVER...THE HRRR HAS BEEN BACKING OFF OF THE FOG ACROSS OUR
NORTHEAST AND HAS BEEN PULLING THE FOG FURTHER BACK TO THE
NORTHEAST AWAY FROM OUR AREA AND CLOSER TO THE STRATUS
DECK...WHICH MAKES SENSE. THE SREF MAY BE OVERDOING LOW LEVEL
MOISTURE GIVEN HOW SNOW COVER IS HANDLED IN THE MODELS. IN
ADDITION...MID TO HIGH CLOUDS WILL MOVE IN LATER TONIGHT LIMITING
RADIATIONAL COOLING AND ALSO LIMITING FOG POTENTIAL.
THEREFORE...DO NOT HAVE ENOUGH CONFIDENCE TO INCLUDE FOG IN THE
FORECAST AT THIS POINT IN TIME. IF WE DO SEE FOG...IT WILL LIKELY
BE NORTHEAST OF THE TRI-CITIES.

SNOW POTENTIAL...A WEAK FAST MOVING OPEN SHORTWAVE WILL TRACK
ACROSS THE NORTHERN AND CENTRAL PLAINS DURING THE DAY ON FRIDAY.
MOST FORECAST MODELS GENERATE A HUNDREDTH OR TWO OF MOISTURE IN
ASSOCIATION WITH THIS TROUGH PASSAGE THAT WOULD AMOUNT TO TRACE
AMOUNTS OF SNOW OR LESS THAN ONE HALF INCH. FORECAST SOUNDINGS
PRETTY CLEARLY SHOW THAT THE TEMPERATURE WILL BE COLD ENOUGH
ACROSS OUR CWA THAT THE ONLY PRECIPITATION TYPE WILL BE SNOW.
HOWEVER...OVERALL LIFT IS WEAK AS NOTED BY FRONTOGENESIS AND
ISENTROPIC SURFACES. THE ONLY THING REALLY GOING FOR THIS WEAK
LITTLE SYSTEM IS A FAIRLY DEEP SATURATED ZONE WITHIN THE DENDRITIC
LAYER THAT COULD LEAD TO A LITTLE LIGHT FLUFFY SNOW. GIVEN THE
LACK OF LIFT WILL JUST CALL FOR LESS THAN ONE HALF INCH OF SNOW
AND MOST AREAS MAY SEE A TRACE OR LESS. THE PRESSURE GRADIENT IS
WEAK AND THUS NOT MUCH WIND IS EXPECTED WITH THIS SHORT WAVE.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 331 PM CST THU FEB 4 2016

ALOFT: NW FLOW WAS DEVELOPING AND WILL DOMINATE THESE PERIODS.
EXCITATION OF THE LONGWAVES UPSTREAM WILL RESULT IN TEMPORARY
AMPLIFICATION OVER N AMERICA...WITH A +2.5 STANDARD DEVIATION RIDGE
OVER THE W AND A -2.5 SD TROF OVER THE ERN USA. THE WAVELENGTH WILL
BROADEN AND THE MAGNITUDE WILL DEAMPLIFY SOMEWHAT MID-NEXT WEEK...
WITH SIGNIFICANT DEAMPLIFICATION PROBABLE LATE NEXT WEEK.

SURFACE: A POTENT CLIPPER WILL BE RACING SE ACROSS THE CAN PRAIRIES
SAT INTO SAT NIGHT. THE ASSOCIATED POLAR COLD FRONT WILL SURGE S AND
CROSS THE FCST AREA SAT NIGHT. IT THEN LOOKS LIKE THE ARCTIC FRONT
SLIDES THRU MON. HIGH PRES ARRIVES TUE AND THEN IT WRN EDGE OF THE
COLDER AIR BEGINS TO EDGE E INTO WED...WITH A WARM FRONT SHARPENING
AND APPROACHING.

NW FLOW IS A DRY PATTERN. SO ANY PRECIP THREATS WILL BE
LIGHT/MINOR.THE CORE OF THE ARCTIC COLD WILL SURGE INTO THE ERN
USA...MISSING USJUST TO THE E. BUT THE WRN FRINGE OF THESE AIR
MASSES WILL KEEPTEMPS GENERALLY AT OR BELOW NORMAL. THE FCST AREA
WILL BE IN THEWARM SECTOR OF A CLIPPER SAT. THAT COULD BE A DAY OF
TEMPORARY ABOVENORMAL TEMPS.


A FEW DAILY DETAILS...

FRI NIGHT: DECREASING CLOUDS.

SAT: TEMPS ARE HIGHLY UNCERTAIN DUE TO THE COMPLICATION OF SNOW
COVER. WOULD NOT BE SURPRISED TO SEE TEMPS WELL INTO THE 40S...EVEN
WITH THE SNOW COVER. IT`S LOOKING VERY WARM IN THE LOW-LVLS...BUT
NOT SURE HOW DEEPLY THE BL MIXES INTO THIS TO BRING IT DOWN.

SUN: COLD SECTOR. WINDY IN CAA...BUT ACTUALY AIR TEMPS NOT THAT
COLD.

COULD SEE A FEW FLURRIES N OF I-80 SAT NIGHT INTO SUN MORNING. JET
FORCING IS STRONG ALOFT...BUT MOISTURE IS LACKING.

MON: TEMPS DROP BACK TO NORMAL...POSSIBLY BELOW. WE MAY NOT BE HIGH
ENOUGH WITH THE WARP-AROUND CLOUD COVER ON THE BACK EDGE OF THE
THERMAL TROF. CAN`T RULE OUT SOME FLURRIES FROM THE TRI-CITIES N AND
E...BUT IT`S NOT IN THE FCST YET.

TUE-WED: QUIET AND DRY.

&&

.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1138 AM CST THU FEB 4 2016

WILL CONTINUE TO CALL FOR VFR CONDITIONS THROUGHOUT THE FORECAST
VALID PERIOD. HOWEVER...THERE IS AT LEAST SOME CHANCE OF FOG THIS
EVENING INTO TONIGHT AS THE WIND DIES DOWN...BUT CONFIDENCE WAS
NOT HIGH ENOUGH TO INCLUDE IN THE TAF AT THIS POINT IN TIME. THERE
IS ALSO A SLIGHT CHANCE OF A FEW LIGHT SNOW SHOWERS OR FLURRIES
FRIDAY MORNING...BUT THE CHANCE IS ALSO TOO LOW FOR PUTTING IN
THE TAF AND WE ARE NOT EXPECTING ANY IMPACT FROM THIS POSSIBLE
LIGHT SNOW.

&&

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

$$

SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY


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