000
FXUS63 KGID 151133
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
633 AM CDT WED MAY 15 2013

.UPDATE...
ISSUED AT 633 AM CDT WED MAY 15 2013

SOME THICKER BATCHES OF MID-HIGH CLOUDS WERE MOVING IN FROM WRN
NEB. FCST HAS THIS IN HAND. WE DID SEE SPRINKLES AT TIF A COUPLE
HRS AGO AND NEW SHWRS ARE DEVELOPING ON RADAR BETWEEN TIF AND BBW.
WILL USE TIMING TOOL AND ADD SOME SPRINKLES TO THE FCST THIS MRNG
N OF I-80. OTHERWISE NO OTHER CHANGES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT WED MAY 15 2013

ALOFT: THE FLOW WAS ZONAL WITH THE POLAR FRONT JET LOCATED ALONG THE
US-CAN BORDER EARLY THIS MRNG. SOME MODEST AMPLIFICATION WILL OCCUR
TODAY-TNGT AS THE SECOND IN A SERIES OF SHRTWV TROF MOVES ONSHORE
INTO THE PAC NW. THIS WILL RESULT IN A SHRTWV RIDGE BUILDING OVER
THE CNTRL PLAINS. MEANWHILE A SMALL CUT-OFF BUT PROGRESSIVE VORT MAX
WAS OVER NV. IT WILL CONTINUE MOVING E AND ARRIVE INTO THE PANHANDLE
BY DAYBREAK THU. THERE IS VERY LITTLE MSTR ASSOCIATED WITH THIS BUT
IT COULD PROVIDE SOME FORCING AND A COLD POCKET ALOFT DURING THE DAY
THU.

SFC: YESTERDAY/S COOL FRONT WAS ROUGHLY ALONG THE NEB-KS BORDER.
THIS FRONT SHOULD SLIP INTO NRN KS AND BECOME QUASI-STATIONARY.
MODELS INDICATE THE FRONT WILL LIFT NWD BACK INTO SRN NEB TNGT. HIGH
PRES WAS OVER THE GULF AND RICH LOW-LVL MSTR WAS ADVANCING N ACROSS
TX. THIS MSTR WILL ARRIVE TO MEET THE FRONT LATE TODAY WITH H8 DWPTS
OF 8-13C. PWAT INCREASES TO 1.25".

EARLY THIS MRNG: VARIABLE CLOUDINESS...ESSENTIALLY CLOUD DEBRIS FROM
OVERNGT SHWRS/TSTMS THAT CONTINUE TO PERCOLATE OVER WRN NEB. TEMPS
ARE MILD.

TODAY: P/SUNNY. POSSIBLY A SHWR OR TSTM FROM NEB HWY 136 S INTO
N-CNTRL KS. MOST PLACES REMAIN DRY. NOT NEARLY AS HOT TODAY BUT
STILL ROUGHLY 12F ABOVE NORMAL. STOCKTON-OSBORNE KS SHOULD STILL
REACH 90-92F.

THUNDER: AM STRUGGLING TO FIND MUCH TO TRIGGER CONVECTIVE ACTIVITY
SAVE FOR THE FRONT ITSELF. WITHOUT ANY DYNAMIC FORCING THE THREAT
FOR SHWRS/TSTMS IS LOW. VERTICAL CROSS SECTIONS SHOW FGEN-ASSOCIATED
LIFT 850-700 MB LAYER...BUT 700-500 SUBSIDENCE IS FCST TO INCREASE
CAPPING S-CNTRL NEB. S OF THE FRONT HOTTER TEMPS WILL BE ENUF TO
ERODE ANY CINH.

MLCAPE IS FCST 1500-2500 J/KG. "IF" TSTMS DEVELOP CAN/T COMPLETELY
RULE OUT SVR WITH THAT MAGNITUDE OF INSTABILITY. 0-5 KM SHEAR OF
15-20 KTS SUGGESTS MULTICELL STORM MODE.

RH: THE AIRMASS ADVECTING IN FROM THE N-NE IS JUST AS BONE DRY AS
YESTERDAY/S HOT AIRMASS. THE 00Z ABR MPX SOUNDINGS ARE BOTHERSOME.
AM CONCERNED MY FCST DWPTS MAY NOT BE LOW ENUF.

TNGT: A FEW SHWRS/TSTMS ARE POSSIBLE AS THE FRONT LIFTS BACK N...BUT
CONFIDENCE IS BELOW AVERAGE. WHILE THERE IS SOME MODEST 10-15 KTS
NORMAL TO THE FRONT BETWEEN 875-800 MB...NOT SURE IF THIS IS ENUF
FOR CONVECTIVE INITIATION. A NARROW LLJ IS FCST TO DEVELOP W OF THE
FCST AREA. WOULD LIKE TO SEE IT FURTHER E TO INCREASE CONFIDENCE
HERE.

MUCAPE 1500-2000 J/KG. 1-5 KM SHEAR 10 KTS OR LESS. IF SOME STORMS
MANAGE TO DEVELOP EXPECT THEY WILL QUICKLY RAIN THEMSELVES OUT.
SLOWER MOVERS WOULD SUPPORT LOCALLY DRENCHING DOWNPOURS.

FOG: MOS AND NAM VSBY GUIDANCE IS SUGGESTIVE OF SOME FOG AND THIS
SEEMS PLAUSIBLE WITH INCREASING LOW-LVL MSTR AND WARM FRONT NEARBY.
MAINTAINED CONTINUITY WITH 4 PM TUE FCST.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 430 AM CDT WED MAY 15 2013

THE BEST CHANCE FOR THUNDERSTORMS APPEARS TO BE THURSDAY AND THEN
AGAIN SATURDAY EVENING THROUGH SUNDAY. THIS CERTAINLY DOES NOT MEAN
THAT IT WILL BE COMPLETELY DRY OUTSIDE OF THESE TWO FAVORED
PERIODS...JUST THAT CONFIDENCE IN SEEING PRECIPITATION IS MUCH LOWER
ON THE OTHER DAYS.

THURSDAY...A 500MB VORT MAX NEAR LAS VEGAS EARLY THIS MORNING WILL
TRACK INTO NEBRASKA/NORTHERN KANSAS BY THURSDAY. THE 12Z AND MOST
RECENT 00Z ECMWF TRACK THE VORT MAX FURTHER NORTH THAN THE 00Z GFS.
THE ECMWF TRACK IS MOST FAVORABLE FOR THUNDERSTORMS NORTH OF
INTERSTATE 80 WHILE THE 00Z GFS FAVORS AREAS ALONG AND SOUTH OF
INTERSTATE 80 INCLUDING NORTH CENTRAL KANSAS. THE 00Z NAM FAVORS OUR
NORTHWEST FOR THUNDERSTORMS. SO AT THIS TIME IT IS HARD TO PINPOINT
WHERE THE BEST CHANCE OF THUNDERSTORMS WILL BE ACROSS OUR CWA ON
THURSDAY...BUT WE CAN DETERMINE THAT THE VORT MAX WILL LIKELY RESULT IN
THUNDERSTORMS ACROSS AT LEAST A FAIRLY SIZABLE PORTION OF OUR
FORECAST AREA. OUR CURRENT FORECAST WILL HAVE THE HIGHEST
THUNDERSTORM CHANCES OVER OUR NEBRASKA ZONES...BUT THIS IS SUBJECT
TO CHANGE DEPENDING ON THE TRACK OF THE VORT MAX. THERE WILL BE
DECENT INSTABILITY WITH SFC BASED CAPE VALUES OF 1500-2000J/KG...BUT
THE 0-6KM DEEP LAYER SHEAR WILL BE WEAK TO MODEST. RECENT MODEL RUNS
HAVE BEEN INCREASING THE 500MB WESTERLY FLOW ASSOCIATED WITH THE
VORT MAX WHICH WHEN COMPARED TO THE SOUTHEASTERLY SFC WINDS COULD
YIELD 0-6KM WIND SHEER VALUES OF 30 TO 40KTS ON THE HIGH END. IF WE
DO SEE THIS INCREASED WIND SHEER THEN ISOLATED SEVERE THUNDERSTORMS
WILL CERTAINLY BE POSSIBLE THURSDAY AFTERNOON AND EVENING. THERE
SHOULD BE A GOOD DEAL OF CLOUD COVER...BUT HIGH TEMPERATURES ARE
STILL EXPECTED TO REACH AROUND 80 FOR MOST LOCATIONS THANKS TO THE
WARM SOUTHERLY FLOW.

FRIDAY...TEMPERATURES WILL WARM AT 700MB WITH A PRETTY STRONG CAP
DEVELOPING THROUGH THE DAY. THEREFORE...WILL BE GOING WITH A DRY
FORECAST THROUGH THE DAYTIME HOURS WHILE CARRYING A SLIGHT CHANCE OF
THUNDERSTORMS OVER WEST/NORTHWEST ZONES FRIDAY EVENING/OVERNIGHT AS
THUNDERSTORMS THAT DEVELOP ALONG THE CO/NE BORDER TRY TO SLIDE EAST
INTO OUR CWA. FORECAST MODELS ARE IN PRETTY GOOD AGREEMENT IN
DEVELOPING THE THE HIGH PLAINS CONVECTION...BUT DIFFER ON WHETHER
THE CONVECTION WILL SURVIVE LONG ENOUGH TO MAKE IT INTO OUR FORECAST
AREA. THE ECMWF HAS BEEN THE MOST AGGRESSIVE WITH BRINGING THIS
CONVECTION INTO OUR CWA FRIDAY EVENING/OVERNIGHT WITH THE FOCUS
BEING WEST OF HIGHWAY 281.

SATURDAY...A DEEP UPPER TROUGH OVER THE ROCKIES WILL BEGIN TO PRESS
INTO THE HIGH PLAINS. THE 00Z GFS AND ECMWF HAVE BOTH SLOWED THIS
SYSTEM DOWN COMPARED TO 24HRS AGO...WITH THE BEST BET OF AFTERNOON
CONVECTION NOW WEST OF OUR CWA EXTENDING FROM NORTHWEST KANSAS INTO
WESTERN NEBRASKA. EXPECT SFC BASED CAPE VALUES ACROSS OUR WESTERN
CWA TO POSSIBLY OVER 2000 J/KG WITH 0-6KM SHEAR OF 30-50KTS. THERE
WILL ALSO BE A FAIRLY STRONG LOW LEVEL JET THAT WILL HELP TO FEED
THE THUNDERSTORMS AND SUPPORT LONGER LIVED STORMS THAT SHOULD TRACK
INTO OUR CWA SATURDAY EVENING AND OVERNIGHT. SEVERE THUNDERSTORMS WILL
CERTAINLY BE POSSIBLE SATURDAY EVENING AND OVERNIGHT IF EVERYTHING
UNFOLDS AS THE 00Z GFS AND ECMWF PROJECT. OUR BEST CHANCE OF
THUNDERSTORMS WILL BE ACROSS OUR WESTERN ZONES AND NORTHERN ZONES
WHERE PRECIPITATION IS LIKELY. WILL HAVE TO WATCH OUT FOR A LOW
STRATUS DECK THAT COULD BE PRESENT ACROSS PORTIONS OF OUR CWA FOR A
GOOD PORTION OF THE DAY. WILL CALL FOR HIGHS IN THE LOWER TO MID
80S...BUT THIS FORECAST MAY BE TOO WARM IF THE CLOUDS LINGER.

SUNDAY...THUNDERSTORMS ARE MORE LIKELY ON SUNDAY NOW WITH THE
FORECAST MODELS INDICATING A SLOW DOWN IN THE UPPER TROUGH.
THEREFORE...HAVE INCREASED THUNDERSTORM CHANCES ON SUNDAY. A FEW
SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS OUR EASTERN ZONES
ALTHOUGH THE BETTER CHANCE FOR SEVERE WEATHER APPEARS TO BE JUST A
LITTLE FURTHER EAST OF OUR CWA UNLESS THIS SYSTEM CONTINUES TO SLOW
DOWN EVEN MORE. SUNDAY WILL BE COOLER WITH SHOWERS AND THUNDERSTORMS
AROUND AND THEN THE COLD FRONT COMING IN DURING THE AFTERNOON.
THEREFORE...WILL BE CALLING FOR HIGHS IN THE UPPER 70S TO AROUND 80.

MONDAY AND TUESDAY...THE UPPER LOW WILL CLOSE OFF AND MOVE VERY
SLOWLY THROUGH THE PLAINS. HIGH TEMPERATURES WILL BE IN THE 70S AND
SHOWER/THUNDERSTORM CHANCES WILL LINGER INTO AT LEAST MONDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 633 AM CDT WED MAY 15 2013

TODAY: MULTI-LAYERED VFR MID-HIGH CIGS. ENE WINDS 10-15 KTS.

TNGT: VFR MID-HIGH CIGS CONTINUE. THERE IS A VERY LOW PROBABILITY
FOR A TSTM BUT NOT INCLUDED IN THE TAF ATTM. NE WINDS DIMINISH TO
AROUND 5 KTS. THE FRONT THAT MOVED THRU YESTERDAY WILL LIFT BACK
N. THIS COULD RESULT IN SOME IFR FOG/STRATUS AFTER 07Z.

CIG CONFIDENCE: HIGH THRU 07Z THU THEN BELOW AVERAGE
VSBY CONFIDENCE: HIGH THRU 07Z THU THEN BELOW AVERAGE
WIND CONFIDENCE: HIGH
WX CONFIDENCE: HIGH THRU 00Z THEN AVERAGE

&&

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

$$

UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...WESELY
AVIATION...HALBLAUB