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000
FXUS63 KGID 152258
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
558 PM CDT WED MAY 15 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 348 PM CDT WED MAY 15 2013

FORECAST COULD BE PRETTY COMPLICATED CONCERNING CHANCES OF
PRECIPITATION FOR THE SHORT TERM.

FOR STARTERS...A NEARLY STATIONARY BOUNDARY IN OUR FAR SOUTHERN CWA
COULD BE THE FOCUS OF SOME AFTERNOON AND EVENING THUNDERSTORM
ACTIVITY. SHEAR IS EXTREMELY WEAK AND INSTABILITY IS MARGINAL AT
BEST. WE STILL HAVE INVERTED V SOUNDINGS...BUT NOT MIXING NEARLY AS
HIGH AS YESTERDAY...AND AIR NOT NEARLY AS DRY. OUR MAIN CONCERN
WOULD BE TO GET AN ISOLATED STRONG TO SEVERE WIND GUST...BUT THIS
WOULD BE A LONGSHOT. WENT CLOSER WITH RAP FOR DEWPOINTS AND WIND
WITHIN THE FIRST 6 TO 12 HOURS AS THE SOLUTIONS OF THIS MODEL HAVE
BEEN SUPERIOR TO OTHERS. I HAD TO INCREASE THE TOP END OF WIND
SPEEDS A BIT AS WE ARE MIXING A BIT BETTER THAN WHAT IS
FORECAST...BUT AS THE FRONT EDGES NORTH...WIND SPEEDS SHOULD
DECREASE ACROSS MUCH OF THE CWA. WENT TOWARD CONSRAW FOR DEWPOINTS
AS WE GET CLOSER TO THE OVERNIGHT HOURS INTO THURSDAY. THERE IS A
BIT OF A SIGNAL FOR SOME FOG TONIGHT FROM THE SREF SO WILL
CONTINUE WITH MENTIONING OF PATCHY FOG...ESPECIALLY AS THE FRONT
MOVES NORTH.

THE FORECAST GETS A LITTLE MUDDLED TONIGHT FOR PRECIPITATION
CHANCES. MODELS ARE GENERALLY LIFTING THE BOUNDARY TO THE NORTH AS A
WARM FRONT. THERE WILL NOT BE MUCH OF A LOW-LEVEL JET TO SUSTAIN ANY
CONVECTION THAT MIGHT FIRE UP THIS AFTERNOON AND EVENING. WITH
DECREASING WITH SUNSET...MOST CONVECTION SHOULD DIE OUT.
OVERNIGHT...HOWEVER...SOME MODELS ARE INDICATING THE POSSIBILITY OF
MORE CONVECTION MAINLY IN THE NORTHERN CWA. THE NMM INDICATES A
POSSIBLE SMALL-SCALE MCS DEVELOP OVER THE CWA OF LBF AND FOLLOW THE
BOUNDARY TO THE EAST ACROSS THE NORTHERN CWA...WHICH MAY POSSIBLY
LAST INTO THE EARLY MORNING HOURS.

THEN ANOTHER LULL IS LIKELY BY LATE MORNING THURSDAY INTO EARLY
AFTERNOON AS THE BOUNDARY TO THE NORTH EITHER CONTINUES TO LIFT
NORTH OR WASHES OUT...DEPENDING ON WHICH SOLUTION IS REALIZED.
EITHER WAY...A LULL IS LIKELY. A MID-LEVEL PERTURBATION IS STILL
FORECAST TO MOVE EAST ACROSS THE AREA BY THURSDAY AFTERNOON...BUT
AMPLITUDE SHOULD REMAIN QUITE LOW. AS A THETA E RIDGE SHIFTS
EAST...ALONG WITH THE WEAK PERTURBATION...WE SHOULD HAVE A GOOD SHOT
OF SOME SHOWERS AND THUNDERSHOWERS...ESPECIALLY WEST/INTO CENTRAL
PARTS OF THE CWA. MUCAPES WILL BE HIGH ENOUGH TO SUSTAIN
THUNDERSTORMS...BUT SHEAR WILL BE WEAK ONCE AGAIN...SO SEVERE
WEATHER WOULD NOT BE OUT OF THE QUESTION...BUT CERTAINLY NO OUTBREAK
IS ANTICIPATED.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 348 PM CDT WED MAY 15 2013

FOCUS OF THE LONG TERM PERIOD WILL CENTER AROUND CHANCES FOR
THUNDERSTORMS...SOME OF WHICH MIGHT BE POSSIBLY SEVERE AT
TIMES...MAINLY SATURDAY AFTERNOON THROUGH SUNDAY EVENING.

THE CUTOFF LOW ACROSS THE DESERT SOUTHWEST WILL FINALLY BEGIN TO
INGEST BACK INTO THE MEAN FLOW THROUGHOUT THE SHORT TERM...FINALLY
SHIFTING OFF TO THE SOUTHEAST ACROSS MISSOURI AND ARKANSAS BY
THURSDAY NIGHT. THROUGH THE OVERNIGHT PERIODS...A WEAK UPPER LEVEL
DISTURBANCE WILL BEGIN TO SHIFT ACROSS THE PLAINS...ON THE BACKSIDE
OF THE UPPER LEVEL LOW. MODELS DISAGREE ON THE DEPTH OF THE
WAVE...WITH THE ECMWF...UKMET AND NAM SOLUTIONS A BIT MORE SHALLOW
THAN THE DEEPER PROGRESSIVE GFS. AT THE SURFACE...MODELS INDICATE A
A DEVELOPING TROUGH ALONG THE FRONT RANGE OF THE ROCKIES...WITH SOME
SORT OF FRONT...WASHED OUT BOUNDARY SHIFTING NORTH OF THE OUTLOOK
AREA. COMBINED WITH THE WAVE AND WARM AIR ADVECTION...MODELS
CONTINUE TO HINT AT AT LEAST A CHANCE FOR PRECIPITATION...WITH THE
GFS HEDGING FURTHER SOUTH INTO KANSAS. AT THIS POINT...REALLY NOT
BUYING INTO THE SOUTHERN SOLUTION AND TRENDING MORE TOWARDS A
NEBRASKA RAIN EVENT.

AFTER THE PASSAGE OF THE UPPER LEVEL WAVE...SUBSIDENCE TAKES
HOLD...AND CURRENT THINKING IS THAT MUCH OF FRIDAY DURING THE DAY
WILL BE DRY. HOWEVER...BY FRIDAY AFTERNOON AND EVENING...ANOTHER
UPPER LEVEL TROUGH WILL BEGIN TO SHIFT INTO THE AREA. WITH THE
EASTWARD PROGRESSION OF THE TROUGH...HEIGHT FALLS...AND A SURFACE
LEESIDE TROUGH...ITS POSSIBLE WESTERN PORTIONS OF NEBRASKA COULD SEE
SOME CONVECTION FRIDAY AFTERNOON. A FAIRLY DECENT LLJ IS EXPECTED TO
DEVELOP ACROSS WESTERN AREAS AND SHIFT EASTWARD OVERNIGHT. THIS
COMBINED WITH A DECENT THETA E RIDGE OVER THE OUTLOOK AREA...WENT
AHEAD AND CONTINUED AT LEAST SLIGHT POPS OVERNIGHT. SHOULD STORMS
DEVELOP...THERE IS PLENTY OF INSTABILITY TO WORK WITH...ABOUT
2000-3000 J/KG. HOWEVER...A STRONG CAP EXISTS WITH 700 MB
TEMPERATURES NEAR 10 TO 11 DEGREES...AND BULK SHEAR IS LIMITED
AROUND 20 TO 30 KTS.

SATURDAY LOOKS TO BE THE MAIN FOCUS OF THE MID TERM PERIOD...AS THE
UPPER LEVEL LOW SHIFTS EASTWARD. BY SATURDAY AFTERNOON...THE SURFACE
TROUGH BECOMES ELONGATED ALONG THE FRONT RANGE. BOTH THE GFS AND
ECMWF SOLUTIONS HAVE BEGUN TO TREND A BIT SLOWER IN PREVIOUS
RUNS...BRINGING IN CHANCES FOR PRECIPITATION ACROSS THE
WEST...MAINLY DURING LATE AFTERNOON AND EVENING. INSTABILITY IS
QUITE HIGH DURING THE SATURDAY AFTERNOON PERIOD THROUGH
OVERNIGHT...WITH 4000 TO 5000 J/KG POSSIBLE. AGAIN...AS HAS BEEN THE
CASE MOST OF THIS WEEK...700 MB TEMPERATURES ARE ON THE ORDER OF 10
TO 12 AND EVEN 13 DEGREES AT TIMES. 0 TO 6 KM BULK SHEAR IS ALSO AT
ITS HIGHEST SATURDAY EVENING...CLIMBING TO NEAR 30 TO 40 KTS...WITH
50 KTS EXPECTED FURTHER WEST.

BY SUNDAY AFTERNOON...THE SURFACE TROUGH AND FRONTAL BOUNDARY WILL
FINALLY MIGRATE EASTWARD ACROSS THE CWA. THIS WILL GIVE US YET
ANOTHER CHANCE FOR PRECIPITATION...POSSIBLY SEVERE AS THE CWA
REMAINS SITUATED JUST ON THE EASTERN FRINGE OF THE UPPER LEVEL
TROUGH. THE ECMWF SOLUTIONS TENDS TO BE A BIT MORE PROGRESSIVE THAN
THE GFS SOLUTION WITH A CLOSED LOW ACROSS NORTHERN NEBRASKA BY 0Z
MONDAY...WHILE THE GFS REMAINS CLOSED OVER THE PANHANDLE. SEVERE IS
BEGINNING TO LOOK POSSIBLE ALSO ON SUNDAY. INSTABILITY DOES NOT LOOK
QUITE AS STRONG AS SATURDAY BUT STILL IS NEAR 2000 J/KG OF MOST
UNSTABLE CAPE. HOWEVER...THE CAP IS ALSO NOT QUITE AS STRONG WITH
700 MB TEMPERATURES ON THE ORDER OF 6 TO 7 DEGREES CELSIUS.
THEREFORE...SEVERE STORMS DO NOT LOOK OUT OF THE QUESTION FOR SUNDAY
AFTERNOON.

THROUGH THE REST OF THE LONG TERM...THE UPPER LEVEL LOW SPINS ACROSS
THE PLAINS GENERATING CHANCES FOR PRECIPITATION THROUGH MONDAY.
HOWEVER...AN UPPER LEVEL RIDGE LOOKS TO SLOWLY BEGIN TO BUILD ACROSS
THE DESERT SOUTHWEST TOWARDS THE BEGINNING OF NEXT WEEK. AS
SUCH...THE UPPER LEVEL LOW EJECTS NORTHWARD...WITH PRECIPITATION
QUICKLY EXITING THE REGION. DECIDED TO PULL OUT ANY SLIGHT MENTION
OF PRECIPITATION ALONG THE FRINGES OF THE CWA AS THE CWA SEEMS TO
BECOME DRY SLOTTED BY MONDAY NIGHT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 558 PM CDT WED MAY 15 2013

VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS...WITH
CONVECTIVE ACTIVITY ALSO POSSIBLE.

INCREASING HIGH LEVEL CLOUDS...WITH BASES NEAR 20000FT AGL...WILL
BE OBSERVED DURING THE TAF PERIOD. A SCATTERED CUMULUS
FIELD...WITH BASES NEAR 6000FT AGL...WILL ALSO LIKELY BE OBSERVED
IN THE AREA THURSDAY AFTERNOON. ISOLATED TO SCATTERED CONVECTION
WILL BE POSSIBLE NEAR THE TERMINAL TONIGHT...PRIMARILY AFTER
06Z...BUT THE PROBABILITY OF MEASURABLE PRECIPITATION BEING
REALIZED AT KGRI IS TOO LOW FOR INSERTION INTO THE TAF AT THIS
TIME. A BETTER CHANCE FOR SCATTERED CONVECTION IS FORECAST AT AND
NEAR KGRI THURSDAY AFTERNOON...WHICH MAY IN TURN PROVIDE
MEASURABLE PRECIPITATION TO THE TERMINAL. THAT BEING
SAID...CONFIDENCE IS ONLY HIGH ENOUGH TO PROVIDE VCTS STARTING 21Z
THURSDAY...FOR THE TIME BEING. THERE IS AN OUTSIDE CHANCE OF
PATCHY FOG DEVELOPMENT AROUND SUNRISE THURSDAY...BUT THE
PROBABILITY OF VISIBILITY RESTRICTION BEING REALIZED AT THE
TERMINAL IS TOO LOW FOR INSERTION INTO THE TAF AT THIS TIME. THE
SURFACE WIND WILL REMAIN FROM THE EAST...SUSTAINED AT AROUND
12KTS...TO START THE TAF PERIOD...BECOMING LIGHT AND VARIABLE
TONIGHT AND THEN BECOMING ESTABLISHED FROM THE SOUTHEAST AT AROUND
12KTS DURING THE DAY THURSDAY.

&&

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

$$

SHORT TERM...HEINLEIN
LONG TERM...SALTZMAN
AVIATION...BRYANT