000
FXUS63 KGID 202316
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
616 PM CDT MON MAY 20 2013

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 349 PM CDT MON MAY 20 2013

MAIN FORECAST CONCERNS WILL BE CHANCES FOR SHOWERS AND
THUNDERSTORMS TONIGHT AND TUESDAY AND TEMPERATURES.

SATELLITE AND OBSERVATIONS SHOW CUMULUS HAVE DEVELOPED ACROSS THE
AREA THIS AFTERNOON. RADAR SHOWS A BAND OF SHOWERS TO THE SOUTHEAST
OF THE FORECAST AREA WHICH SHOULD STAY OUT OF THE AREA. A FEW MORE
SHOWERS OR EVEN SPRINKLES HAVE DEVELOPED TO THE NORTHWEST AND WEST.
WITH THE UPPER LEVEL LOW IN THE NORTHERN PLAINS THESE SHOWERS SHOULD
MOVE INTO THE FORECAST AREA LATER THIS AFTERNOON AND THIS EVENING.

THE UPPER LEVEL LOW IN THE NORTHERN PLAINS WILL BE THE MAIN
WEATHER FEATURE DURING THE PERIOD. WITH THIS UPPER LOW SPINNING IN
THE NORTHERN PLAINS...SMALL LOBES OF ENERGY GET PUSHED INTO THE
FORECAST AREA. WITH THE CUMULUS THAT IS ACROSS THE AREA...AS SOME
OF THAT ENERGY MOVES INTO THE AREA SOME SHOWERS COULD DEVELOP. THE
SMALL BAND OF SHOWERS TO THE NORTHWEST WILL BE THE MAIN AREA THAT
WILL AFFECT THE FORECAST AREA THIS AFTERNOON INTO THIS EVENING.
EXPECT THAT MOST OF THESE WILL BE SHOWERS...BUT IN THE SOUTHEAST
PART OF THE FORECAST AREA LATE THIS AFTERNOON THERE IS SOME MUCAPE
AROUND 1200 J/KG. THIS COULD MAKE FOR A FEW THUNDERSTORMS IF THE
SHOWERS GET TO THE SOUTHEAST. DURING THE EVENING THE MUCAPE DROPS
OFF QUICKLY AND THE CHANCE FOR THUNDERSTORMS DIMINISHES NOT TOO
LONG AFTER SUNSET. DURING THE EVENING THE CHANCE FOR SHOWERS ALSO
DIMINISHES AND IS CONFINED TO THE NORTHWEST PART OF THE AREA
CLOSER TO THE UPPER LOW AND THE LOBES OF ENERGY MOVING THROUGH
NORTHERN NEBRASKA.

THE CHANCES FOR SHOWERS CONTINUES LATE TONIGHT AND DURING THE DAY
ON TUESDAY BUT SHOULD BE SLIGHT CHANCES AND SPOTTY SHOWERS. ALSO
THE SHOWERS WILL BE MAINLY IN THE NORTHERN PART OF THE FORECAST
AREA.

ANOTHER CONSEQUENCE OF THE UPPER LEVEL LOW IS THAT COOLER AIR IS
SPUN INTO THE AREA FROM THE NORTH. LOW TEMPERATURES TONIGHT WILL BE
AROUND 50 DEGREES AND HIGHS TOMORROW WILL BE MOSTLY IN THE 60S TO
AROUND 70.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 349 PM CDT MON MAY 20 2013

GUIDANCE SUGGESTS THE LONG-TERM FORECAST PERIOD SHOULD START OFF
DRY AS THE MID LEVEL LOW...CURRENTLY OVER THE CENTRAL
PLAINS...BEGINS MOVING EAST...OUT OF OUR AREA. THE RESULTANT LACK
IN KINEMATIC FORCING AS A MID TO UPPER LEVEL RIDGE AXIS MOVES
OVERHEAD SUGGESTS LITTLE IN THE WAY OF PRECIPITATION WILL BE
REALIZED ACROSS OUR AREA WEDNESDAY AND THURSDAY. STARTING THURSDAY
NIGHT HOWEVER...IT APPEARS AS THOUGH THE MID TO UPPER LEVEL RIDGE
WILL BREAK DOWN SOMEWHAT AS SEVERAL MID LEVEL PERTURBATIONS BEGIN
EJECTING FROM A WESTERN-CONUS LONG WAVE TROUGH. PERIODS OF
INCREASED DPVA AND MID LEVEL THERMAL ADVECTION MAY BRING PERIODIC
PRECIPITATION TO OUR AREA THURSDAY NIGHT ONWARD. IN
ADDITION...INCREASED LOW LEVEL THERMAL ADVECTION ALONG THE AXIS OF
AN ~850MB JET STREAK MAY ALLOW FOR ENHANCED CHANCES FOR MEASURABLE
PRECIPITATION DURING THE OVERNIGHT HOURS. ALLBLEND RESPONDED BY
PROVIDING POPS TO MOST ALL OF OUR CWA THURSDAY NIGHT ONWARD AND
THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART.

LOW LEVEL RETURN FLOW AND RESULTANT LOW LEVEL MOISTURE FLUX INTO
THE CENTRAL PLAINS SHOULD ALLOW FOR INCREASING POTENTIAL
INSTABILITY ACROSS OUR AREA THURSDAY NIGHT ONWARD. THE OPERATIONAL
GFS AND EC BOTH SUGGEST DEEP LAYER MUCAPE VALUES OF
2000-3000J/KG...ALONG WITH DEEP LAYER BULK SHEAR VALUES OF
20-30KTS...WILL OVERTAKE OUR AREA SATURDAY THROUGH THE END OF THE
FORECAST PERIOD. GIVEN THE APPARENT POTENTIAL FOR STRONG UPDRAFT
PRODUCTION DURING THIS TIME PERIOD...WILL GO AHEAD AND OUTLOOK
SEVERE WEATHER IN THE HWO SATURDAY ONWARD.

LITTLE CHANGE IN THE LOW LEVEL AIRMASS SUGGESTS A SIMILAR HIGH
AND LOW TEMPERATURE WILL BE REALIZED WEDNESDAY THROUGH FRIDAY FOR
MOST LOCATIONS ACROSS OUR CWA. LOW LEVEL RETURN FLOW AND RESULTANT
LOW LEVEL WARM AIR ADVECTION SHOULD THEN ALLOW FOR WARMER WEATHER
TO FINISH OUT THE FORECAST PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 607 PM CDT MON MAY 20 2013

KGRI WILL SEE INTERMITTENT CLOUD COVER THRU THE TAF PERIOD UNDER
THE UNFLUENCE OF AN UPPER LOW PRESSURE SYSTEM CROSSING THE CENTRAL
PLAINS. CLOUDS MAY SCATTER FOR A TIME THIS EVENING...WITH CLOUD
COVER INCREASING AGAIN TONIGHT AND PERSISTING THRU TUESDAY AS THE
UPPER SYSTEM TRANSLATES FARTHER SOUTHEAST. FOR THE MOST
PART...CLOUDS ARE EXPECTED TO BE IN THE VFR CATEGORY BUT MAY DROP
TO MVFR AT TIMES. RAIN SHOWERS OR SPRINKLES WILL BE HIT OR MISS
AND DID NOT MENTION JUST YET.

&&

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

$$

SHORT TERM...JCB
LONG TERM...BRYANT
AVIATION...FAY