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000
FXUS63 KGID 161803
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
103 PM CDT THU MAY 16 2013

.UPDATE...
ISSUED AT 1123 AM CDT THU MAY 16 2013

UPDATED THE FORECAST FOR THIS AFTERNOON AND NIGHT MAINLY FOR
PRECIPITATION CHANCES. USED AN EXTRAPOLATION TOOL FOR THE TIMING
OF THE INSTABILITY AXIS AS IT MOVES EAST. INCREASED CHANCES OF
PRECIPITATION CONSIDERABLY AS IT MOVES EAST AS MODELS ARE NOT
HANDLING GENERAL QPF WELL. QPF WILL REMAIN MAINLY BELOW A TENTH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT THU MAY 16 2013

MAIN FOCUS DURING THE SHORT TERM WILL BE THUNDERSTORM CHANCES
THIS AFTERNOON. ANY STORMS THAT DO DEVELOP WILL BE
ISOLATED...MAINLY ACROSS NEBRASKA. THERE IS A GROWING CHANCE OF PATCHY
FOG THIS MORNING. THE BEST CHANCE FOR FOG THIS MORNING WILL BE
SOUTH OF I-80.

MODELS ARE SUGGESTING CAPE AROUND 1000 TO 1500 J/KG AND A WEAK SHEAR
ENVIRONMENT. FORECAST SOUNDINGS ARE INDICATING AN INVERTED V
THIS AFTERNOON WITH MIXING UP TO AROUND 7000 FEET...WHICH COULD
CAUSE SOME GUSTY WIND AT THE SURFACE. AS A RESULT...MAIN THREAT
WILL BE SEVERE WIND TODAY...BUT HAIL COULD ALSO BE A POSSIBILITY GIVEN
THE MARGINAL INSTABILITY.

AS AN UPPER LEVEL TROUGH CONTINUES TO AMPLIFY OVER THE WEST
COAST...A MID LEVEL VORTICITY MAXIMUM IS FORECAST TO EJECT EASTWARD
OVER THE CENTRAL PLAINS LATER THIS AFTERNOON AROUND PEAK HEATING.
DURING THE DAY...A LEE TROUGH WILL DEVELOP AS A RESULT OF THE VORT
MAX...AND THIS SHOULD HELP ADVECT BOUNDARY LAYER MOISTURE INTO THE
CENTRAL PLAINS. RIGHT NOW WE ARE FORECAST TO HAVE DEWPOINTS IN THE
UPPER 50S AND LOWER 60S...HENCE THE MARGINAL INSTABILITY PROGGED
FOR THE AFTERNOON HOURS. THE FOCUS OF THUNDERSTORM DEVELOPMENT
WILL BE IN THE VICINITY OF A WARM FRONT FORECAST TO PUSH NORTH
ACROSS NEBRASKA. DEPENDING HOW FAR NORTH THE WARM FRONT PUSHES
WILL DETERMINE HOW MUCH OF THE CWA ACTUALLY EXPERIENCES
THUNDERSTORMS. IF THE FRONT GETS TOO FAR NORTH...WE COULD MISS
OUT COMPLETELY ON PRECIPITATION. MODELS HAVE BACKED OFF A LITTLE
ON PRECIPITATION OVER THE CWA...WHICH IS NOTEWORTHY.

TEMPERATURES OVER THE SHORT TERM WILL BE ABOVE NORMAL FOR THIS TIME
OF YEAR. NORMAL TEMPERATURES ACROSS THE TRI-CITIES AREA FOR THIS
TIME OF YEAR ARE AROUND 72 FOR A HIGH AND NEAR 50 FOR A LOW.
HIGHS SHOULD GET UP TO THE LOWER 80S TODAY.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 415 AM CDT THU MAY 16 2013

THE UPPER LEVEL TROUGH OF LOW PRESSURE ACROSS THE WEST COAST WILL
BEGIN TO PUSH INLAND ON FRIDAY...AND SLOWLY CROSS THE INTERMOUNTAIN
WEST OVER THE UPCOMING WEEKEND. THIS TROUGH WILL EVENTUALLY LIFT
INTO THE GREAT LAKES REGION TOWARDS THE MIDDLE OF NEXT WEEK...AS
ANOTHER STRONGER UPPER LEVEL LOW ORGANIZES ACROSS THE PACIFIC
NORTHWEST AND BRIEF RIDGING ALOFT IS OBSERVED LOCALLY. LONG TERMS
MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE GENERALLY PATTERN
EXPECTED ACROSS THE PLAINS THROUGH THE MIDDLE OF NEXT WEEK...WITH
SOME DISCREPANCIES IN THE CHANCES AS TIMING OF PRECIPITATION AS THIS
WILL BE RELATED TO INDIVIDUAL SHORTWAVES MOVING ACROSS THE LOCAL
AREA OUT OF THE LONGWAVE TROUGH TO OUR WEST.

STARTING OFF FRIDAY...EXPECT DRY CONDITIONS TO PREVAIL ACROSS THE
LOCAL AREA AS RIDGING ALOFT WILL BE REALIZED...WITH 850 MB TEMPS
ONCE AGAIN CLIMBING INTO THE LOWER 20S ACROSS MUCH OF THE FORECAST
AREA. WITH NO NOTABLE SHORTWAVES AHEAD OF THE MAIN TROUGH ON
FRIDAY...WENT AHEAD AND REMOVED CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS THE LOCAL AREA...AS WELL AS BUMPED UP HIGH
TEMPERATURES A FEW DEGREES...AS THIS LOOKS TO BE THE WARMEST DAY
OF THE PERIOD. BY SATURDAY...EXPECT THE APPROACHING TROUGH TO
BEGIN TO HAVE A LARGER IMPACT ON THE LOCAL WEATHER AS THE FIRST OF
SEVERAL UPPER LEVEL DISTURBANCES CROSSES THE LOCAL AREA. WITH
PLENTY OF INSTABILITY BUILDING ACROSS THE PLAINS...AND AN
INCREASING LOW LEVEL JET FOCUSED ACROSS SOUTH CENTRAL NEBRASKA
SATURDAY NIGHT...EXPECT THE POTENTIAL FOR SOME SEVERE
THUNDERSTORMS SATURDAY AFTERNOON AND NIGHT...AND NOT
SURPRISINGLY...THE DAY 4 OUTLOOK FROM SPC CURRENTLY HIGHLIGHTS THE
POTENTIAL FOR SEVERE WEATHER ACROSS MUCH OF THE LOCAL AREA.

THEREAFTER...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST
ACROSS THE ENTIRE FORECAST AREA THROUGH THE START OF THE NEW
WORKWEEK...UNTIL THE MAIN UPPER LEVEL TROUGH LIFTS NORTHEAST...AND
MORE STABLE AIR BEGINS TO INVADE THE REGION. INITIALLY...THE PRIMARY
FOCUS FOR SHOWERS AND THUNDERSTORMS WILL BE ALONG A COLD FRONT
FORECAST TO CROSS THE LOCAL AREA SUNDAY AFTERNOON AND
EVENING...WHICH SHOULD PROVIDE ENOUGH SHEAR COMBINED WITH
INSTABILITY ACROSS THE REGION...FOR ANOTHER ROUND OF POTENTIALLY
SEVERE THUNDERSTORMS. ADDITIONALLY...THIS FRONT SHOULD DROP
TEMPERATURES TO NEAR OR JUST BELOW CLIMATOLOGY TO START OFF THE NEW
WORK WEEK...WITH UPPER 60S AND LOWER 70S FORECAST FOR BOTH MONDAY
AND TUESDAY. WHILE THERE WILL CONTINUE TO BE PERIODIC CHANCES FOR
BOTH SHOWERS AND THUNDERSTORMS ON MONDAY AND TUESDAY...AS THE UPPER
LEVEL TROUGH LINGERS ACROSS THE REGION...WIDESPREAD PRECIPITATION IS
NOT EXPECTED AT THIS TIME...AND KEPT CHANCES FOR PRECIPITATION IN
THE LOW CHANCE CATEGORY IN MOST SPOTS. TEMPERATURES WILL THEN
REBOUND SOME BY THE MIDDLE OF NEXT WEEK...AS HEIGHTS BEGIN TO RISE
BEHIND THE DEPARTING TROUGH AND INSTABILITY STARTS TO WANE...SO KEPT
FORECAST DRY TUESDAY NIGHT ONWARD.

&&

.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1240 PM CDT THU MAY 16 2013

MAIN ISSUE OF THE TAF IS TIMING OF THE INSTABILITY AXIS
APPROACHING THE TERMINAL. THERE IS AN OUTSIDE CHANCE OF SOME
LIGHTNING...SO INCLUDED CB WITH THE CEILING FOR THE LATE
AFTERNOON/EARLY EVENING. THERE IS ANOTHER SMALL CHANCE OF SHOWERS
AND PERHAPS A THUNDERSHOWER LATE THIS EVENING WITH ANOTHER SMALL
AREA OF CONVECTION FARTHER TO THE WEST...BUT THIS SHOULD MAINLY
AIM SOUTH AND THERE WILL NOT BE MUCH SUPPORT FOR SUSTAINING
CONVECTION. THERE IS SOME INDICATION OF MVFR VISIBILITY LATE
TONIGHT INTO FRIDAY MORNING FROM MODELS/ENSEMBLES.

&&

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

$$

UPDATE...HEINLEIN
SHORT TERM...GUERRERO
LONG TERM...SAR
AVIATION...HEINLEIN