000
FXUS63 KGID 180559
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1259 AM CDT SAT MAY 18 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 323 PM CDT FRI MAY 17 2013

MAIN FORECAST CONCERNS WILL BE THUNDERSTORMS FOR SATURDAY
AFTERNOON AND TEMPERATURES.

SATELLITE SHOWS ONLY A FEW CLOUDS AROUND THE AREA AND MOST OF
THEM ARE CIRRUS THAT ARE FAIRLY THIN. SOUTH WINDS HAVE BEEN
INCREASING A LITTLE DURING THE DAY.

AS A SURFACE LOW PRESSURE SYSTEM DEVELOPS IN THE HIGH PLAINS
TONIGHT WINDS WILL CONTINUE FROM THE SOUTH. THIS WILL BRING IN LOW
LEVEL MOISTURE TO THE PLAINS. THE BEST MOISTURE WILL BE IN THE
SOUTHWEST PART OF THE FORECAST AREA. LOOKS LIKE THERE COULD BE
SOME LOW CLOUDS AND AT LEAST SOME PATCHY FOG FOR THE SOUTHWEST
PART OF THE FORECAST AREA. THE SREF HAS THE BEST POSSIBILITY FOR
LOWER VISIBILITIES IN THE FAR SOUTHWEST.

THE NEXT QUESTION WILL BE IF THERE WILL BE SOME PRECIPITATION
LATE TONIGHT INTO SATURDAY MORNING. THERE IS SOME WARM ADVECTION
ALONG WITH THE SIGNIFICANT LOW LEVEL MOISTURE...BUT THERE IS ALSO
STILL RIDGING AT 500MB AND CIN OF AROUND -400 J/KG. NOT CONVINCED
THERE WILL BE CONVECTION...BUT HAVE SOME CONCERN FOR SOME DRIZZLE
WITH THE LOWER CLOUDS. WILL LEAVE IT DRY FOR NOW...BUT WILL NEED
TO WATCH TO SEE IF ANY DRIZZLE DEVELOPS.

BY SATURDAY AFTERNOON AN UPPER LEVEL WAVE STARTS TO MOVE INTO THE
REGION. THERE IS STILL SOME CIN BUT IT STARTS TO DIMINISH ESPECIALLY
IN THE SOUTHWEST PART OF THE FORECAST AREA. EXPECT THUNDERSTORMS TO
DEVELOP TO THE WEST OR SOUTHWEST DURING THE AFTERNOON AND MOVE INTO
THE AREA. TIMING IS STILL A BIT QUESTIONABLE BASED ON WHEN AND WHERE
THE STORMS DEVELOP BUT THEY SHOULD START MOVING INTO THE WEST DURING
THE AFTERNOON. THE STORMS THAT MOVE INTO THE AREA WILL LIKELY BE
SEVERE. EXPECT LARGE HAIL AND DAMAGING WINDS TO BE THE PRIMARY
THREAT.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 PM CDT FRI MAY 17 2013

AN ACTIVE PERIOD OF WEATHER BEGINS RIGHT AWAY WITH SEVERE WEATHER
POSSIBLE SATURDAY NIGHT AND SUNDAY...FOLLOWED BY A WANDERING UPPER
LEVEL LOW PRESSURE INFLUENCING OUR WEATHER THROUGH MID NEXT WEEK.

SATURDAY NIGHT...SPC MODERATE RISK FOR SEVERE WEATHER JUST ISSUED
AND INCLUDES 4 TO 6 COUNTIES IN WESTERN FORECAST AREA...MAINLY
WEST OF A KEARNEY TO PHILLIPSBURG. HONESTLY...WAS A LITTLE SURPRISED
BY THE MODERATE COMING OUT A DAY OR MORE AHEAD OF POTENTIAL
THUNDERSTORM EVENT. AS THE FORECAST GOES HERE...THUNDERSTORMS TO
THE WEST OF THE FORECAST OR VERY NEARBY...WILL TRY TO MOVE EAST
BUT RUN INTO A STRONG CAPPING INVERSION...WHICH WILL INHIBIT
WIDESPREAD STORM DEVELOPMENT ACROSS THE SOUTHEAST PART OF OUR
FORECAST AREA. THAT SAID...SHEAR AND INSTABILITY PROFILES ARE
IMPRESSIVE AND WILL RESULT IN PROBLEMATIC SEVERE STORMS...WHERE
STRONG CAPPING IS OVERCOME. IT WOULD NOT BE SURPRISING IF THE
STORMS FAVORED A MORE NORTHEASTWARD TRACK HAVING TROUBLE EATING
INTO THE FORECAST +12 H7 TEMPERATURES. WEAK PERTURBATION LIFT
WILL SUPPORT STORMS...AND HI-RES MODELS SHOW THAT...BUT THEY
ALSO SHOW THE POTENTIAL FOR A VERY LIMITED COVERAGE TYPE EVENT
FOR THE SOUTHERN/EASTERN FORECAST AREA. HAVE FAVORED THE NORTHERN
AND WESTERN AREAS FOR HIGHER PRECIPITATION CHANCES...AS I AM
REASONABLY CONFIDENT IN THE PRESENCE OF STORMS...SOME OF WHICH WILL
BE SEVERE.

SUNDAY...THIS DAY COULD ALSO BE INTRIGUING...BUT THERE ARE MANY
UNCERTAINTIES. THE MAIN WAVE/UPPER LOW WITH SYNOPTIC SCALE LIFT
PUSHES INTO NEBRASKA/KANSAS BY LATE MORNING. MODERATE INSTABILITY
WILL BE IN PLACE AND BY MIDDAY WARM MID LEVEL TEMPERATURES START
TO NUDGE EAST. 0-6KM FORECAST TO RANGE FROM 25-45 KTS...HOWEVER
SURFACE BOUNDARY POSITION IS IN QUESTION. MOST MODELS HAVE THE
BOUNDARY OVER OUR FAR EASTERN FORECAST AREA...ROUGHLY HIGHWAY 81. BY
MIDDAY...CONVECTIVE INHIBITION IS WEAK...INSTABILITY GOOD...LIFT
IS WIDESPREAD AND STRONG...AND THE RESULT SHOULD BE A FAIRLY
WIDESPREAD AND QUICK INCREASE IN THUNDERSTORM COVERAGE...WITH
STORMS POSSIBLY SEVERE. DEPENDING ON THE LOCATION AND TIME OF THE
SURFACE FRONT AND MAIN UPPER WAVE KICKING THROUGH...THERE MAY BE
SOME RISK FOR A MORE WIDESPREAD SEVERE EVENT SUNDAY AFTERNOON OVER
THE EASTERN PART OF THE FORECAST AREA. TOO SOON TO PINPOINT
THINGS...BUT CERTAINLY WORTH WATCHING.

BY MONDAY THIS SYSTEM BECOMES MORE OF A CUT OFF...SLOWLY
MEANDERING LOW PRESSURE TO OUR NORTH AND EAST. IT WILL BE
COOLER...ESPECIALLY MONDAY THROUGH WEDNESDAY. WE WILL SEE PERIODIC
SHOWER AND ISOLATED THUNDERSTORMS IN THE CYCLONIC FLOW AROUND THE
LOW...BUT NONE LOOK TOO SUBSTANTIAL...AND TIMING IS HARD AT THIS
POINT. BY THURSDAY UPPER RIDGE TRIES TO BUILD INTO THE CENTRAL
PLAINS...BUT SOME MODELS SUGGEST SOME PRECIPITATION/MOISTURE
SURGING NORTH BACK UP THE FRONT RANGE...AND POSSIBLE SPILLING
EAST. LOTS OF UNCERTAINTY AND HAVE NOT STRAYED FROM SUGGESTED
GUIDANCE AND CURRENT FORECAST.

&&

.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1255 AM CDT SAT MAY 18 2013

DETERIORATING CONDITIONS ARE EXPECTED AT KGRI AS AN AREA OF LOW
LEVEL STRATUS ADVECTS NORTHWARD FROM KANSAS INTO NEBRASKA DURING
THE EARLY MORNING HOURS. IN ADDITION TO MVFR STRATUS...EXPECT SOME
LIGHT DRIZZLE TO DEVELOP BY EARLY MORNING...WHICH WILL BE SLOW TO
BURN OFF. ONCE THE STRATUS THINS...EXPECT DAYTIME HEATING TO
CONTRIBUTE TO BUILDING INSTABILITY...WITH SHOWERS AND
THUNDERSTORMS EXPECTED TO FORM ACROSS WESTERN NEBRASKA BY LATE
AFTERNOON...PUSHING EASTWARD TOWARDS THE TERMINAL AFT 00Z. WINDS
WILL GENERALLY REMAIN SOUTHEASTERLY THROUGHOUT THE VALID
PERIOD...WITH GUSTS TO 20KTS OR SO POSSIBLE DURING THE AFTERNOON
HOURS.

&&

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

$$

SHORT TERM...JCB
LONG TERM...MORITZ
AVIATION...SAR