Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 141202 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
702 AM CDT MON APR 14 2014

.UPDATE...
12Z AVIATION DISCUSSION UPDATED BELOW. ALSO...BASED ON RADAR AND
OBS...HAVE INCREASED SNOW SHOWER CHANCES INTO THE AFTERNOON.

&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH WEDNESDAY
SEVERAL DETAILS TO KEEP TRACK OF THIS MORNING WITH RESPECT TO
SHORT TERM FCST. MAIN FCST CHALLENGE THOUGH WILL SYSTEM THAT
AFFECTS THE CWA TUESDAY NIGHT THROUGH WEDNESDAY.

FIRST UP...NEED TO DEAL WITH 700HPA WAVE DROPPING SOUTH ACROSS CWA
TODAY. MODELS ARE CONT TO ADVERTISE A WEAK 700HPA THETA-E RIDGE
ASSOC WITH WEAK WAVE...AND OBS UPSTREAM SHOW POCKETS OF LIGHT
SNOW. BUFKIT SOUNDINGS FOR AREAS ALONG AND EAST OF JAMES RIVER
SHOW VERY STEEP LOW LEVEL LAPSE RATES...LEADING TO THOUGHTS OF
SNOW SQUALLS ACROSS THE COTEAU REGION. BASED UPON ND RADAR
RETURNS...HAVE EXPANDED PCPN SHIELD BACK TO THE WEST A BIT...UPPED
POPS AND WENT WITH CATEGORICAL WORDING. HAVE A FEELING THAT ONCE
PCPN MOVES INTO CWA...POPS WILL NEED TO BE RAISED INTO LIKELY/OCNL
TERRITORY. ALSO..BASED UPON FCST SOUNDINGS AND 925MB HPA
TEMPS...WENT WITH FROZEN VERSUS LIQUID PCPN TYPE. ANTICIPATE HIGH
TEMPS TO BE SIMILAR TO SUNDAY HIGHS...IF NOT A DEGREE OR TWO
COLDER.

HIGH PRESSURE THEN SETTLES OVER AREA TONIGHT THROUGH
TUESDAY...WITH STRONG WAA PUSH SEEN DURING THE DAY TUESDAY.
GFS/NAM POINT TOWARD SOME INCREASING 700HPA OMEGA ASSOC WITH WAA
PUSH. HAVE INCREASED CLOUD COVER DUE TO THIS...AND WOULDN`T BE
SURPRISED TO SEE VIRGA DEVELOP...BUT HAVE HELD OFF ON ANY MENTION
OF PCPN AT THIS TIME.

TUE NIGHT AND WEDNESDAY IS A TALE OF TWO MODELS. THE NAM IS VERY
BULLISH ON PCPN ACROSS THE CWA...ESPECIALLY THE HIGHWAY 12
CORRIDOR. LINGERS DEVELOPING SFC AND 700HPA LOW IN THE NRN PLAINS
A BIT LONGER...ALLOWING SNOW TOTALS TO PILE UP. WINTER STORM
WATCH/WARNING CRITERIA IS MET...IF YOU BELIEVE THE NAM. THE GFS
AND EC HOWEVER REMAIN CONSISTENTLY PROGRESSIVE WITH THE 700HPA
SYSTEM...AND ARE STRONGER WITH NORTHWARD PUSH OF WAA/DRY SLOTTING
ASSOCIATED WITH SYSTEM TUESDAY NIGHT. BECAUSE OF
CONSISTENCY...HAVE CONTINUED TO LEAN ON AN EC/GFS SOLN FOR THE
TUESDAY NIGHT/WED TIME FRAME. ONE CONCERN IS THAT EVEN THE GFS
WHEN LOOKING AT 850HPA TEMPS AND 850HPA-700HPA CRITICAL THICKNESS
VALUES...FZRA IS A POSSIBILITY ACROSS THE NRN TIER COUNTIES.
BUFKIT SOUNDINGS ALSO SHOW IP/UP/FZRA FOR KABR THROUGH 12Z
WEDNESDAY. HAVE ADDED MENTION OF FZRA TO THE NRN COUNTIES TUESDAY
NIGHT. WITH CAA MAKING A RETURN BY 12Z WEDNESDAY...ALL PCPN EXCEPT
FOR ACROSS THE SRN/SERN COUNTIES SHOULD HAVE TURNED OVER TO ALL
SNOW.. AGAIN BASED ON LOW LEVEL TEMPS/CRITICAL THICKNESS
VALUES...SRN/SERN CWA SHOULD STAY ALL RAIN. FOR NOW...WILL MAKE A
MENTION OF FZRA IN THE HWO...BUT HOLD OFF ON ANY HEADLINES.


.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
THE MODELS SHOW DECENT AGREEMENT IN THE LONG TERM GOING FROM MUCH
BELOW NORMAL TEMPERATURES EARLY ON TO ABOVE NORMAL TEMPERATURES
LATE IN THE PERIOD. THE PERIOD BEGINS WITH AN UPPER LEVEL LOW
PRESSURE TROUGH AND ITS ACCOMPANYING PRECIPITATION POSSIBLY STILL
AFFECTING OUR FAR EASTERN CWA EARLY WEDNESDAY EVENING. MAY HAVE TO
ADD IN A POP FOR THIS LATER ON BUT LEFT IT DRY FOR NOW. OTHERWISE...THE
MODELS SHOW A LARGE UPPER LEVEL LOW PRESSURE AREA/TROUGH IN
SOUTHERN CANADA DROPPING SLOWLY SOUTHEAST ACROSS OUR REGION
THROUGH FRIDAY NIGHT. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE
WILL DOMINATE OUR WEATHER FROM WEDNESDAY NIGHT INTO FRIDAY NIGHT.
HIGHS WILL BE FROM 10 TO 20 DEGREES BELOW NORMAL FOR THURSDAY AND
FRIDAY IN THE UPPER 30S TO AROUND 50 DEGREES. THE HIGH TEMPERATURES WILL
THEN WARM INTO THE 50S AND 60S BY SATURDAY AND SUNDAY. THERE MAY
BE SOME COLD AIR DAYTIME HEATING SCATTERED RAIN/SNOW SHOWERS ON
THURSDAY AND FRIDAY WITH THE LOW PRESSURE AREA ALOFT...BUT WILL
LEAVE IT DRY FOR NOW. OTHERWISE...THERE ALSO MAY BE A WEAK UPPER
LEVEL SYSTEM AFFECT THE NORTH AND NORTHEAST CWA SATURDAY AS
HEIGHTS BUILD INTO SUNDAY. THUS...HAVE IN SLIGHT CHANCES OF LIGHT
RAIN ON SATURDAY WITH DRY CONDITIONS ON SUNDAY.



&&

.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

A SHORT WAVE TROUGH DROPPING ACROSS THE REGION THROUGH THE
AFTERNOON WILL BRING SOME LOW VFR/HIGH MVFR CLOUDS TO THE TERMINALS.
ALSO...WITH THE LIFT FROM THIS TROUGH ALONG WITH STEEP LAPSE
RATES...SCATTERED SNOW SHOWERS WILL MOVE ACROSS THE REGION THAT
COULD BRING VISIBILITIES TO 3 MILES OR LESS AT TIMES. THE SHORT
WAVE WILL MOVE OUT LATE THIS AFTERNOON AND EVENING TAKING THE
CLOUDS AND SNOW SHOWERS WITH IT.



&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...MOHR
SHORT TERM...HINTZ
LONG TERM...MOHR
AVIATION...MOHR

WEATHER.GOV/ABERDEEN





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