Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 021108
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
508 AM CST MON MAR 2 2015

.SHORT TERM...(TODAY THROUGH TUESDAY DAYTIME)
ISSUED AT 509 AM CST MON MAR 2 2015

APOLOGIZE FOR THE LATE DISCUSSION...BUT SPENT PLENTY OF TIME
TRYING TO FINE-TUNE THE MANY TRICKY NUANCES OF THESE NEXT 36
HOURS. WHILE CONFIDENCE IS HIGH IN ELEMENTS SUCH AS WIND...WHICH
WILL BECOME BREEZY TODAY/TONIGHT FROM THE SOUTH AND THEN
DOWNRIGHT-WINDY TUESDAY OUT OF THE NORTH...CONFIDENCE IS
CONSIDERABLY LOWER REGARDING WHETHER OR NOT PARTS OF THE CWA COULD
SEE POTENTIALLY IMPACTFUL FREEZING DRIZZLE DEVELOPMENT TONIGHT
INTO TUESDAY MORNING. THERE IS ALSO AT LEAST SOME CHANCE FOR A
BRIEF PERIOD OF SNOW AND/OR SLEET MAINLY WITHIN COUNTIES NORTH OF
I-80 VERY LATE TONIGHT INTO TUESDAY MORNING...BUT THIS CONTINUES
TO LOOK LIKE A VERY MINOR (LESS THAN HALF-INCH) ACCUMULATION
LOCALLY...WITH ANY CHANCE FOR 1+ INCH ACCUMULATION REMAINING AT
LEAST SLIGHTLY NORTH OF THE CWA AND ESPECIALLY ALONG THE NEB/SD
BORDER. SPEAKING OF SNOW...ALTHOUGH EXPECTED TO PRODUCE NOTHING
MORE THAN A DUSTING OR SO...PARTS OF THE CWA COULD SEE A BRIEF
BOUT OF SNOW THIS MORNING AS EVIDENCED BY CURRENT RADAR TRENDS
OVER NORTH CENTRAL KS.

BRIEFLY COVERING THE HERE-AND-NOW...OVERNIGHT TEMPS HAVE REMAINED A
BIT WARMER THAN EXPECTED YESTERDAY THANKS MAINLY TO PLENTIFUL
MID-HIGH CLOUD COVER...WITH LOWS ON TRACK TO BOTTOM OUT NO LOWER
THAN THE MID-20S MOST PLACES...WITH SOME COLDER EXCEPTIONS MAINLY
NORTH. AT THE SURFACE....LIGHT EAST-SOUTHEAST BREEZES ARE
DEVELOPING IN RESPONSE TO HIGH PLAINS PRESSURE FALLS.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA DEPICT
WEST-SOUTHWEST FLOW ALOFT OVER THE CENTRAL PLAINS...WELL-
DOWNSTREAM FROM A LARGE-SCALE TROUGH OVER THE WESTERN CONUS.

NOW BREAKING THINGS DOWN OVER THE NEXT 36 HOURS IN 6-12 HOUR
BLOCKS:

EARLY THIS MORNING THROUGH MID-DAY: THE MOST IMMEDIATE ISSUE IS
THE AFOREMENTIONED BAND OF LIGHT SNOW CURRENTLY MOVING TOWARD THE
STATE LINE OUT OF KS...AND WHETHER OR NOT IT MIGHT HOLD TOGETHER
AND/OR EXPAND IN COVERAGE TO CONTINUE OVERSPREADING THE MAJORITY
OF THE CWA. THOSE MODELS THAT DID CATCH ONTO THIS LIGHT SNOW
POTENTIAL CLEARLY SHOW IT IS TIED TO A MODEST WING OF MID LEVEL
SATURATION/ISENTROPIC LIFT. WOULD BE SURPRISED IF THIS SNOW BAND
LEAVES BEHIND MORE THAN A QUICK TENTH OF AN INCH OR SO...BUT WILL
ADVERTISE AT LEAST SLIGHT CHANCE POPS EXPANDING NORTHWARD ACROSS
THE CWA AS THE MORNING WEARS ON...MUCH AS DEPICTED BY THE LATEST
HRRR. CONFIDENCE IS FAIRLY HIGH THAT ANY OF THIS SNOW SHOULD BE
EXITED OFF TO THE EAST-NORTHEAST OF THE CWA BY NOON.

THIS AFTERNOON: ASSUMING THAT ANY MORNING LIGHT SNOW IS GONE BY
NOON...HAVE MAINTAINED A DRY AFTERNOON FORECAST DESPITE GENERALLY
MOSTLY CLOUDY SKIES PERSISTING. THE MAIN STORY THIS AFTERNOON WILL
BE INCREASING SOUTH WIND...WITH A TIGHTENING PRESSURE GRADIENT
PROMOTING SUSTAINED SPEEDS GENERALLY 20-25 MPH WITH GUSTS TO
AROUND 30 MPH. MADE LITTLE CHANGE TO HIGH TEMPS THIS
AFTERNOON...AIMING MOST AREAS INTO THE 37-40 RANGE...BUT IF CLOUDS
END UP BEING A BIT LESS THAN EXPECTED WOULD NOT BE SURPRISED TO
SEE THINGS JUMP A BIT WARMER THAN THIS.

THIS EVENING AND TONIGHT: THE MILLION DOLLAR QUESTION HERE IS
WHETHER IT IS SIMPLY A BREEZY AND UNEVENTFUL NIGHT...OR WHETHER
AREAS OF DRIZZLE/FREEZING DRIZZLE COULD DEVELOP AND CAUSE SOME
ISSUES. ON THE LARGE-SCALE SCENE...A LEAD SHORTWAVE DISTURBANCE
WILL EMERGE INTO THE CENTRAL PLAINS OUT OF THE PARENT WESTERN
TROUGH...SENDING A FAIRLY STRONG SURFACE LOW OF AROUND 1000 MB
EASTWARD GENERALLY ALONG THE NEB/KS BORDER...WHICH SHOULD BE
POSITIONED OVER THE SOUTHERN HEART OF OUR CWA BY 12Z/6AM. AHEAD OF
THIS LOW...BREEZY SOUTH WIND WILL PREVAIL OVERNIGHT...USHERING IN
INCREASING LOW LEVEL MOISTURE AND LIKELY LEADING TO THE
DEVELOPMENT OF WIDEPSREAD LOWER STRATUS. THE BIG UNCERTAINTY IS
DRIZZLE POTENTIAL. WHILE THE LATEST NAM CLEARLY SUPPORTS DRIZZLE
DEVELOPMENT...THIS FORECASTER WONDERS HOW MUCH OF THIS COULD BE
"FALSELY AIDED" BY THE MODEL`S TYPICALLY-OVERDONE SNOW COVER
SCHEME AND BOUNDARY LAYER RELATIVE HUMIDITY. INTERESTINGLY...THE
GFS SEEMS LESS INCLINED TO DEVELOP DRIZZLE. GIVEN THE UNCERTAINTY
THAT STILL REMAINS...OPTED TO "TONE DOWN" THE FORECAST CONFIDENCE
IN DRIZZLE/FREEZING DRIZZLE DEVELOPMENT A BIT BY USING "CHANCE"
WORDING INSTEAD OF "AREAS/WIDESPREAD"...WHICH TENDS TO IMPLY THAT
IT WILL IN FACT HAPPEN. OF COURSE IF IT DOES...AREAS ESPECIALLY
NEAR/NORTH OF INTERSTATE 80 THAT STAND THE BEST CHANCE OF DROPPING
BELOW FREEZING COULD SEE SOME LIGHT ICING. BUT EVEN TEMPERATURES
CARRY LOW-CONFIDENCE...AS ALTHOUGH THE CURRENT FORECAST IS
PROBABLY AIMED TOWARD THE COLDER SIDE OF POSSIBILITIES...WOULD NOT
BE SURPRISED IF THE STEADY SOUTHERLY FLOW ACTUALLY BRINGS A
GREATER-THAN-EXPECTED TEMPERATURE RISE AND EITHER KEEPS MANY AREAS
ABOVE FREEZING...OR RISES THEM ABOVE FREEZING AS THE NIGHT WEARS
ON. OBVIOUSLY THIS WOULD ERADICATE ANY ICING THREAT AND KEEP ANY
DRIZZLE AS PLAIN NON-FREEZING VARIETY. LAST BUT NOT LEAST...VERY
LATE TONIGHT THE EDGES OF THE INVADING STRONG COLD FRONT SHOULD
JUST START TO APPROACH THE NORTHERN/WESTERN FRINGES OF THE
CWA...AND ENOUGH MID LEVEL SATURATION/FORCING COULD EXIST TO START
BRINGING THE SOUTHWARD FRINGES OF AN AREA OF SLEET/SNOW OVER
NORTHERN NEBRASKA INTO OUR FAR NORTHERN COUNTIES MAINLY NORTH OF
HIGHWAY 92. ANY ACCUMULATION LOCALLY SHOULD BE QUITE MINIMAL.

TUESDAY DAYTIME: THE OVERALL-BIGGEST STORY OF THE DAY WILL
PROBABLY BE THE STRONG NORTH WIND...WITH ESPECIALLY THE NORTHEAST
1/2 OF THE CWA ON TRACK TO EXPERIENCE SEVERAL HOURS OF SUSTAINED
SPEEDS AROUND 30 MPH/GUSTS 40-45 MPH AS THE STRONG COLD FRONT
BLASTS THROUGH. WILL CONTINUE TO CARRY THESE STRONG WINDS IN THE
HAZARDOUS WEATHER OUTLOOK (HWOGID)...BUT NEIGHBORING EASTERN
OFFICES THAT STILL ISSUE WIND ADVISORIES MAY VERY WELL NEED ONE.
PRECIP-WISE...THE MORNING HOURS BRING A CONTINUED CHANCE OF
DRIZZLE/FREEZING DRIZZLE TO MUCH OF THE AREA...BUT ONCE AGAIN ITS
COVERAGE/IMPACT IS STILL VERY MUCH IN QUESTION. ONLY COUNTIES
ALONG/NORTH OF INTERSTATE 80 HAVE ANY MENTION OF SNOW/SLEET DURING
THE MORNING...AND EVEN THESE CHANCES ARE STILL LESS THAN 50
PERCENT GIVEN THAT VARIOUS MODELS ARE IN GREAT AGREEMENT KEEPING
THE VAST MAJORITY OF SNOW ACCUMULATION JUST NORTH OF THE CWA.
BARRING MAJOR CHANGES...WOULD BE SURPRISED TO SEE ANYBODY WITHIN
THE CWA PICK UP MORE THAN ONE-HALF INCH. WITH THE MID-LEVELS
DRYING OUT BY MID-DAY...THE AFTERNOON ONLY FEATURES A LINGERING
SLIGHT CHANCE OF FLURRIES...AND EVEN THIS WOULD ONLY OCCUR IF ANY
REMAINING LOW STRATUS SQUEEZES OUT SOME ACTIVITY WITHIN THE
DENDRITIC LAYER. DAYTIME HIGH TEMPS WILL LIKELY BE REACHED WITHIN
THE FIRST FEW HOURS AFTER SUNRISE...WITH AT LEAST SLOWLY- FALLING
TEMPS DEFINING THE MAJORITY OF THE DAY...AND MOST OF THE CWA WELL-
DOWN INTO THE 20S BY LATE AFTERNOON. FOLLOWING THE AFTERNOON LULL
IN MEASURABLE PRECIP...ONE LAST CHANCE FOR LIGHT SNOW MOVES IN
TUESDAY NIGHT AS COVERED IN THE LONG TERM SECTION BELOW...

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 314 AM CST MON MAR 2 2015

GUIDANCE SUGGESTS AN UPPER TROPOSPHERIC SHORT WAVE WILL EXTEND
FROM SOUTH-CENTRAL CANADA INTO THE NORTHERN PLAINS TO START THE
LONG-TERM FORECAST PERIOD AT 00Z WEDNESDAY. ANOTHER SHORT WAVE IS
ALSO EXPECTED TO EXIST OVER THE SOUTHWESTERN CONUS AT THE START OF
THE LONG-TERM FORECAST PERIOD.

THE SHORT WAVE OVER SOUTH-CENTRAL CANADA AND THE NORTHERN PLAINS
IS CURRENTLY EXPECTED TO MOVE SOUTHEAST INTO PORTIONS OF THE
CENTRAL PLAINS AND MID-MISSISSIPPI VALLEY TUESDAY NIGHT INTO THE
DAY WEDNESDAY...WITH THE TROUGH AXIS EXPECTED TO CLEAR MUCH OF OUR
AREA BY DAYBREAK WEDNESDAY. GUIDANCE FROM THE NAM...OPERATIONAL
GFS AND EC ALL SUGGEST ENOUGH OMEGA WILL ACCOMPANY THIS SHORT WAVE
FOR PRECIPITATION PRODUCTION ACROSS MUCH OF OUR CWA 00-12Z
WEDNESDAY. WENT AHEAD WITH 20-40% POPS ACROSS MUCH OF THE CWA AS A
RESULT. TAKING A BLEND OF THE NAM...OPERATIONAL GFS AND EC
PROVIDES LIQUID PRECIPITATION AMOUNTS OF 0.02-0.05" ACROSS THE
CWA. FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...ALSO FROM
THE NAM...OPERATIONAL GFS AND EC...ALL SUGGEST THE LOWER
TROPOSPHERE WILL REMAIN SUPPORTIVE FOR SNOW...AND SUCH HAS ALSO
BEEN PRESENTED IN THE OFFICIAL FORECAST. TAKING A BLEND OF THE NAM
AND OPERATIONAL GFS SUGGESTS SNOW-WATER RATIOS GENERALLY IN THE
15-20:1 RANGE WILL BE REALIZED. TAKING THESE SNOW-WATER
RATIOS...ALONG WITH THE AFOREMENTIONED LIQUID
PRECIPITATION...GENERALLY PROVIDES BETWEEN A HALF INCH AND ONE
INCH OF FRESH SNOW ACROSS THE CWA TUESDAY NIGHT INTO EARLY
WEDNESDAY MORNING. ALTHOUGH THERE WILL LIKELY BE A STRONG
NORTH/NORTHWEST SURFACE WIND TO START TUESDAY EVENING...GUIDANCE
SUGGESTS THE BOUNDARY-LAYER PRESSURE GRADIENT SHOULD WEAKEN
CONSIDERABLY THROUGH THE OVERNIGHT HOURS AND IN FACT...BY THE TIME
SNOWFALL REALLY KICKS IN ACROSS THE AREA...A SUSTAINED WIND OF
5-15KTS IS ALL THAT IS EXPECTED. GIVEN ALL THIS...ANY SNOWFALL AND
ACCUMULATION TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING IS NOT
CURRENTLY EXPECTED TO BE SIGNIFICANT OR PRESENT A "HIGH-IMPACT"
EVENT.

NORTHWESTERLY TO QUASI-ZONAL UPPER TROPOSPHERIC FLOW IS THEN
EXPECTED TO OVERTAKE THE CENTRAL PLAINS WEDNESDAY THROUGH FRIDAY
NIGHT. GUIDANCE SUGGESTS AN OVERALL LACK IN OMEGA WILL ALSO KEEP
US DRY DURING THIS TIME PERIOD AND SUCH HAS BEEN PRESENTED IN THE
OFFICIAL FORECAST.

SATURDAY INTO SATURDAY NIGHT...THERE ARE INDICATIONS FROM THE
OPERATIONAL GFS AND EC OF AN UPPER TROPOSPHERIC SHORT WAVE
CLEARING PORTIONS OF THE CENTRAL PLAINS. THAT SAID...THE EC IS
~300 MILES FARTHER SOUTHWEST WITH ITS PLACEMENT OF THE SHORT WAVE
TROUGH AXIS WHEN COMPARED THE OPERATIONAL GFS...AND BOTH MODELS
SUGGEST OMEGA WILL REMAIN FAIRLY WEAK WITH THIS SYSTEM. SUPERBLEND
OPTED TO KEEP US DRY SATURDAY INTO SATURDAY NIGHT AND AT THIS
TIME...AM NOT CONFIDENT ENOUGH TO INTRODUCE ANY POPS FOR THE
WEEKEND...BUT THIS IS STILL SOMETHING TO KEEP AN EYE ON THROUGH
THE NEXT FEW DAYS. NORTHWESTERLY UPPER TROPOSPHERIC FLOW SHOULD
THEN OVERTAKE THE REGION TO FINISH THE FORECAST PERIOD
SUNDAY...WITH DRY CONDITIONS ALSO FORECAST.

A COOLER BOUNDARY-LAYER AIR MASS SHOULD PERSIST ACROSS THE REGION
THROUGH WEDNESDAY...WITH HIGHS IN THE 20S AND LOWS IN THE SINGLE
DIGITS AND TEENS CURRENTLY FORECAST. GUIDANCE THEN SUGGESTS A
SOUTH/SOUTHEASTERLY BOUNDARY-LAYER WIND FIELD AND RESULTANT
THERMAL ADVECTION WILL PROVIDE A SUBSTANTIAL WARMING TREND TO
FINISH THE FORECAST PERIOD...WITH HIGHS IN THE 40S AND 50S AND
LOWS IN THE 20S TO NEAR 30 BETWEEN LATE THIS WEEK AND EARLY NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1208 AM CST MON MAR 2 2015

CONFIDENCE IS REASONABLY HIGH THAT PREVAILING VFR CONDITIONS WILL
PERSIST THROUGH THE MAJORITY OF THE PERIOD BEFORE DETERIORATING TO
MVFR/POSSIBLY IFR CEILING LATE IN THE PERIOD ON MONDAY EVENING. IN
SHORT...THE FIRST 18 HOURS OR SO OF THE PERIOD CARRIES A FAIRLY
HIGH CONFIDENCE OF VFR...ALTHOUGH WILL HAVE TO WATCH A BRIEF
WINDOW OF OPPORTUNITY GENERALLY BETWEEN 11Z-15Z DURING WHICH A
BAND OF LIGHT SNOW COULD PASS THROUGH THE AREA. ALTHOUGH MVFR
VISIBILITY/CEILING CANNOT BE RULED OUT WITH THIS POTENTIAL LIGHT
SNOW BAND...KEPT BOTH CATEGORIES IN LOW-END VFR FOR NOW. THEN
LATER IN THE EVENING...EXPECT LOW STRATUS TO OVERSPREAD THE AREA.
ALTHOUGH SOME LIGHT DRIZZLE OR EVEN FREEZING DRIZZLE IS NOT OUT OF
THE QUESTION LATE IN THE PERIOD...HAVE OMITTED ANY OF THIS PRECIP
MENTION FOR NOW. AS FOR WIND...GENERALLY LIGHT/VARIABLE BREEZES
EARLY THIS MORNING WILL STEADILY PICK UP OUT OF THE SOUTH AS THE
DAY WEARS ON...WITH SEVERAL HOURS OF SUSTAINED SPEEDS AROUND
20KT/GUSTS TO AROUND 30KT EXPECTED ESPECIALLY DURING THE
AFTERNOON...BEFORE SUBSIDING ONLY SLIGHTLY DURING THE EVENING.

&&

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

$$

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



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