Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 210528
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1228 AM CDT TUE APR 21 2015

.UPDATE...
ISSUED AT 1228 AM CDT TUE APR 21 2015

AN EXTENSIVE SHIELD OF ALTOCU AROUND 10K FT WAS DROPPING INTO THE
FCST AREA FROM THE N. THIS WILL COMPLICATE HOURLY TEMP CURVES AS
IT MOVES THRU...WITH TEMPS STABILIZING/HOLDING STEADY...THEN
RESUMING THE NOCTURNAL FALL WITH CLEARING.

OTHERWISE...NO SIG ISSUES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 1228 AM CDT TUE APR 21 2015

THIS SERVES AS A FIRST DRAFT OF SOME INITIAL THOUGHTS FOR THIS
SHIFT...

ALOFT: NW FLOW THRU TONIGHT WITH AN ANOMALOUSLY DEEP LOW SLOWLY
LIFTING FROM THE GREAT LAKES INTO ONTARIO...AND A W COAST RIDGE THAT
MAKES SLOW BY STEADY PROGRESS INTO THE INTERMOUNTAIN W. WV IMAGERY
SHOWS A VERY SUBTLE SHORTWAVE TROF DIVING S OUT OF SASKATCHEWAN INTO
THE DAKOTAS. THIS TROF WILL TURN SE AND HEAD INTO THE MIDWEST
TONIGHT.

TODAY: THE PATCH OF ALTOCU SHOULD CLEAR THE AREA...THEN SUNNY AND
BREEZY AGAIN. SCATTERED ALTOCU WILL REDEVELOP AROUND 9K FT AFTER 3
PM.

SUSTAINED WINDS AND GUSTS WERE INCREASED HIGHER THAN MOS IN DEEP
MIXING.

TONIGHT: CLEARING EARLY WITH DIMINISHING WINDS.


.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 359 PM CDT MON APR 20 2015

WE START OUT THE LONG TERM TUESDAY NIGHT WITHIN NORTHWEST FLOW...AS
THE NORTHERN STREAM ROUNDS INTO THE BASE OF A VORTEX CENTERED OVER
SOUTHEASTERN CANADA. ALSO A CLOSED LOW WILL UNDERCUT AN AMPLIFIED
RIDGE TO THE WEST. AT THE SURFACE...HIGH PRESSURE BUILDS IN BEHIND A
COLD FRONT...BUT THIS IS EXPECTED TO BE A DRY PASSAGE AS THE AMBIENT
ENVIRONMENT LOOKS DRY ON MODEL SOUNDINGS. THE SURFACE PRESSURE
GRADIENT IS RATHER STRONG BEHIND THE COLD FRONT AND I HAVE BUMPED UP
WIND SPEEDS MANUALLY DIRECTLY BEHIND THE COLD FRONT PASSAGE TUESDAY
NIGHT...AND ALSO INCREASED WIND GUSTS USING CONSRAW. WIND SHOULD
BECOME RELATIVELY LIGHT TOWARD DAWN FOR MOST AREAS AS THE INCREASED
WIND SPEED WILL BE PRIMARILY JUST BEHIND THE COLD FRONT.

AS THE VORTEX MOVES EAST...WE WILL BE SITUATED WITHIN WEAK FLOW BY
WEDNESDAY NIGHT...BETWEEN THE NORTHERN AND SOUTHERN STREAMS. WE
SHOULD REMAIN GENERALLY DRY...ALTHOUGH THIS MAY NOT BE CERTAIN AS
NORTHWEST FLOW CAN BE A BIT UNPREDICTABLE...BUT AMBIENT ENVIRONMENT
CONTINUES TO LOOK PRETTY DRY.

SPLIT FLOW CONTINUES FOR THURSDAY...WITH NEAR NORMAL TEMPERATURES
AND POTENTIAL FOR A STATIONARY BOUNDARY NEARBY AS THE SURFACE HIGH
SHIFTS EAST. THE INSTABILITY AXIS SHOULD STILL BE OFF TO THE
WEST...AND WILL GENERALLY HOLD OFF MUCH OF THE PRECIPITATION TO THE
SOUTHWEST FOR THURSDAY...AS WE SHOULD BE STABLE WITH NOT MUCH
SUPPORT FOR GENERATING PRECIPITATION...BUT THERE COULD BE JUST
ENOUGH MOISTURE RETURN TO GET A FEW SHOWERS GOING. MUCAPES INCREASE
ENOUGH IN OUR SOUTH TO INCLUDE THUNDER FOR THURSDAY NIGHT IN MOST OF
OUR NORTH CENTRAL KANSAS AREA.

FRIDAY COULD BE SOGGY AS A GOOD AMOUNT OF MOISTURE AND LIFT OCCUR
AHEAD OF THE APPROACHING WAVE MOVING OUT OF THE ROCKIES. NUMERICAL
MODELS ARE IN PRETTY GOOD AGREEMENT WITH TIMING AND
PLACEMENT...PLACING THE TRACK OF THE MID-LEVEL LOW NEAR OR SOUTH OF
OUR CWA...PLACING US IN A FAVORABLE AREA FOR MEASURABLE
PRECIPITATION. I BUMPED UP CHANCES OF RAIN A BIT MORE COMPARED TO
THE PREVIOUS FORECAST FOR FRIDAY. MUCAPES INDICATE A CONTINUED SHOT
AT ISOLATED THUNDER IN OUR NORTH CENTRAL KANSAS COUNTIES...BUT THERE
REALLY IS NOT ENOUGH INSTABILITY ADVERTISED TO SUPPORT THUNDER TO
THE NORTH OF THIS.

THE WEEKEND...HOWEVER...IS LOWER CONFIDENCE. NUMERICAL MODELS
DIVERGE AS THE ECMWF TAKES THE CLOSED LOW EAST OF THE CWA AND THE
GFS OPENS UP THE WAVE AS IT MOVES EAST. DRY CONDITIONS ARE NOT
GUARANTEED FOR THE WEEKEND AS PERTURBATIONS WITHIN NORTH STREAM FLOW
COULD MAKE THEIR WAY INTO OUR AREA...ESPECIALLY BY SUNDAY NIGHT AS
MODELS PRODUCE SPOTTY QPF IN THE REGION DURING THE WEEKEND INTO
MONDAY. THIS IS ADVERTISED AHEAD OF AN APPROACHING RIDGE TO THE
WEST...WHICH IS MUCH MORE AMPLIFIED IN THE LATEST RUN OF THE GFS
COMPARED TO A MORE BROAD SOLUTION BY THE ECMWF. THEREFORE...I LEFT
SMALL CHANCES OF SHOWERS FOR THE WEEKEND INTO MONDAY...BUT LEFT OUT
THUNDER AS INSTABILITY CONTINUES TO BE LACKING.

&&

.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z TUE NIGHT)
ISSUED AT 1228 AM CDT TUE APR 21 2015

OVERNIGHT: VFR ALTOCU CIGS AROUND 10K FT. LIGHT W WINDS.
CONFIDENCE: HIGH

TUE: VFR. CLEARING EARLY THEN DIURNAL ALTOCU FORM AROUND 9K FT IN
THE 20Z-21Z TIME FRAME. NW INCREASE 15Z-16Z AND COULD GUST AS HIGH
AS 30 KTS. CONFIDENCE: HIGH

TUE EVE: VFR CLEARING. WIND DIMINISH TO UNDER 10 KTS AND SHIFT TO
NE. CONFIDENCE: HIGH

&&

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

$$

UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB


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