Hail in Kansas, August 31, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
331 PM CDT TUE AUG 31 2010

.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT.  FOCUS REMAINS ON
CHCS FOR TSTMS.  THE PATTERN ALOFT FEATURED A RIDGE ACROSS THE GULF
COAST STATES...SOUTHWEST FLOW ACROSS THE PLAINS...WITH A TROUGH
ALONG THE NORTHERN/CENTRAL ROCKIES.  WATER VAPOR IMAGERY REVEALS A
SUBTROPICAL MOISTURE PLUME HAS BEGUN TO WORK ITS WAY NORTHWARD INTO
NORTHERN KANSAS AND SOUTHEAST NEBRASKA EARLY THIS AFTN...WHILE AT
THE SURFACE A COLD FRONTAL BOUNDARY WAS LOCATED JUST TO THE SOUTH OF
A LINE FROM YORK TO PHILLIPSBURG. AHEAD OF THE FRONT...TEMPS HAVE
CLIMBED TO THE UPPER 80S/LOW 90S WITH DPS IN THE UPPER 60S TO THE
LOWER 70S. IN CONTRAST...BEHIND THE FRONT...TEMPERATURES HAVE
FALLEN BACK TO THE 70S WITH DPS IN THE 50S THE LOWER 60S. LAPS
DATA SHOWS SURFACE BASED INSTABILITY OF ROUGHLY 2500 J/KG TO 3000
J/KG ACROSS OUR EAST/SOUTHEAST CWA...AND MODELS INDICATE SHEAR
VALUES ALONG/AHEAD OF THE FRONT AROUND 30KTS. HAVE BEEN CONTINUING
TO WATCH THE PROGRESSION OF THE FRONT AS LOCATIONS BEHIND THE
BOUNDARY WILL SEE DWINDLING OPPORTUNITY FOR CONVECTION...WHILE
CHCS FOR STORMS ARE STILL FAIR GAME ALONG AND AHEAD OF THE
BOUNDARY. AS IT STANDS AND IN TIMING OUT THE FRONT...OUR SOUTHEAST
CWA STILL WILL BE THE FAVORED AREA FOR CONVECTION AND THE
POTENTIAL FOR SEVERE WEATHER THIS EVENING BEFORE THE FRONT MOVES
THROUGH. THE PRIMARY HAZARDS FROM THE STORMS WILL BE LARGE
HAIL...DAMAGING WINDS AND LOCALLY HEAVY RAINFALL.

THEN OVERNIGHT...MODELS ARE NOT CONSISTENT ON WHETHER OR NOT
CONVECTION WHICH DEVELOPS ALONG THE LEE OF THE ROCKIES THIS EVENING
WILL HOLD TOGETHER AND ROLL EASTWARD LATE TONIGHT/EARLY WEDNESDAY.
IN ADDITION...AN INCREASING LLVL JET OVER THE MID LEVEL BOUNDARY MAY
ALSO FOCUS CONVECTION...HOWEVER THE ORIENTATION OF THE JET IS TOWARD
THE MISSOURI RIVER AND THIS ACTIVITY SHOULD FOCUS TO OUR EAST.
ELEVATED INSTABILITY PROGS TONIGHT ARE NEAR 1000 J/KG TO 1500 J/KG
AND ON WEDNESDAY MUCAPES ARE ALSO PROGGED NEAR 2000 J/KG WITH DEEP
LAYER SHEAR OF 30 TO 40KTS.  REMNANT CONVECTION FM HIGH PLAINS
DEVELOPMENT MAY REACH OUR CWA EARLY WEDNESDAY...WITH REDEVELOPMENT
POSSIBLE IN ISENTROPIC LIFT ON THE 315K SURFACE AHEAD OF THE MID
LEVEL WAVE...AND INCREASING UPPER DYNAMICS WITH PROGRESSING
WAVE...100KT JET NOSING SOUTH FM THE NORTHERN ROCKIES.  HAVE
MAINTAINED POPS GENERALLY AS THEY WERE AS CONFIDENCE IS NOT HIGH
ENOUGH TO RAISE OR LOWER THEM GIVEN THE DIFFERENCES IN THE MODELS.

.LONG TERM...12Z THURSDAY THROUGH TUESDAY. MAIN FORECAST CONCERN LIES WITH
TEMPERATURES.

MODELS IN PRETTY GOOD AGREEMENT AT THE START OF THE LONG TERM
PERIOD...SHOWING THE NORTHERN AND CENTRAL PLAINS REMAINING UNDER THE
INFLUENCE OF A TROUGH ASSOCIATED WITH A LOW PRESSURE SYSTEM CROSSING
SRN CANADA...WHILE RIDGING REMAINS ALONG BOTH COASTS. COUPLE OF
STORIES FOR THURSDAY...ONE BEING WITH THE CONTINUED EASTWARD
PROGRESS OF THIS UPPER LEVEL TROUGH...AND WHILE THE FIRST HALF OF
THE DAY WILL SEE MORE IN THE WAY OF CLOUDS AND POSSIBLY EVEN A FEW
SHOWERS AROUND THE REGION...EXPECTING THAT MAIN AREAS OF PRECIP WILL
BE OUTSIDE OF THE CWA SO KEPT THE FORECAST DRY. BY EVENING...BEST
FORCING ASSOCIATED WITH THE TROUGH WILL BE WELL EAST OF THE
CWA...IMPACTING THE KS/MO/IA/WI/MN AREAS.  THE OTHER ISSUE FOR THE
DAY WILL BE WITH A FRONTAL PASSAGE...AND THE RESULTING WINDS AND
COOLER/DRIER AIR.  AT 12Z THURSDAY...THERE IS GOOD AGREEMENT SHOWING
THE COLD FRONT BASICALLY DRAPED THROUGH IN A SW/NE ORIENTATION
THROUGH THE MIDDLE OF THE CWA.  BY MIDDAY...THIS FRONT IS EXPECTED
TO BE ON THE VERY SERN FRINGE OF THE CWA OR BE OUTSIDE.  MODELS HAVE
COME INTO BETTER AGREEMENT SHOWING GOOD PRESSURE RISES...SO
EXPECTING THAT AT LEAST A PORTION OF THE LATE MORNING/EARLY TO MID
AFTERNOON HOURS WILL SEE SOME PRETTY GUSTY NORTH/NORTHWEST
WINDS...AND DID TREND SPEEDS UP APPROACHING ADV CRITERIA...SO IT
WILL BE SOMETHING TO MONITOR IN SUBSEQUENT SHIFTS. GETTING INTO
THURSDAY NIGHT AND FRIDAY...THE DRY FORECAST CONTINUES...WITH MORE
AMPLIFIED NORTHWESTERLY FLOW DEVELOPING IN THE UPPER LEVELS ACROSS
THE PLAINS AS LOW PRESSURE DEEPENS OVER THE GREAT LAKES REGION AND
RIDGING BUILDS FURTHER NORTH ACROSS THE ROCKIES.  AT THE SFC...HIGH
PRESSURE CONTINUES TO SETTLE INTO THE REGION BEHIND THE COLD
FRONT...BRINGING DIMINISHING WINDS.  MAIN CHANGES MADE TO THURSDAY
NIGHT/FRIDAY WERE TO TAPER BACK FRIDAY HIGHS SOME INTO GENERALLY THE
MID/UPPER 70S...AND TO TREND BACK DEW POINTS MORE INTO THE 40S WITH
MODELS IN GOOD AGREEMENT WITH THIS DRIER AIRMASS.  ACTUALLY WONT BE
TOO SURPRISED IF DEW POINTS /AT LEAST FOR A PERIOD OF TIME/ NEED TO
BE TAPERED BACK EVEN MORE.

THROUGH THE WEEKEND...NO SIGNIFICANT CHANGES EXPECTED...WITH NO
PRECIPITATION FORECAST.  UPPER LEVEL FLOW REMAINS GENERALLY
NORTHWESTERLY BUT BECOMES A BIT MORE ZONAL TOWARD THE END OF THE
WEEKEND AS THE PATTERN DEAMPLIFIES WITH THE LOW PRESSURE SYSTEM
MOVING FURTHER N/NE AND ANOTHER SYSTEM MOVING ONTO THE PAC NW.  SFC
HIGH PRESSURE CONTINUES TO SLIDE TO THE EAST WITH A TROUGH
DEVELOPING ALONG THE HIGH PLAINS...BRINGING MORE SOUTHERLY WINDS TO
THE CWA. TEMPERATURES ALSO BEGIN WARMING...AND BY SUNDAY AM
EXPECTING HIGHS BACK INTO THE MID 80S/LOWER 90S.

INTO EARLY NEXT WEEK...UPPER LEVEL FLOW GRADUALLY SHIFTS FROM ZONAL
ON MONDAY TO MORE SOUTHWESTERLY INTO TUESDAY AS THE PAC NW
LOW/TROUGH DIGS FURTHER SOUTH ALONG THE WEST COAST AND THE RIDGE
AXIS SLIDES TO THE EAST OF THE CWA.  MODELS ARE HINTING AT ANOTHER
POSSIBLE FRONTAL PASSAGE ON TUESDAY...BUT DECIDED TO KEEP DRY WITH
THERE STILL SOME UNCERTAINTIES BETWEEN MODELS WITH TIMING/LOCATION
AND IT BEING DAY 7.  KEPT HIGH TEMPERATURES GENERALLY IN THE MID 80S
TO LOWER 90S.

&&

.AVIATION...18Z TAF. A COLD FRONTAL BOUNDARY HAS JUST PASSED
KGRI...AND WINDS HAVE SHIFTED TO THE NORTHWEST BEHIND THE
BOUNDARY. A NORTHERLY WIND COMPONENT IS EXPECTED THROUGH
TONIGHT...THEN WINDS MAY BECOME MORE VARIABLE AT TIMES ON
WEDNESDAY WITH THE CHC OF SHRA/TSRA. WITH THE FRONTAL BOUNDARY NOW
THRU KGRI...CHCS FOR TSTMS HAVE DECREASED FOR THIS EVENING/TONIGHT
BUT CARRY INTO WEDNESDAY AS A SHORTWAVE TROUGH MOVES THROUGH.
CLOUD CEILINGS BEHIND THE BOUNDARY RANGE FROM 2-3K FEET AND HAVE
KEPT CLOUD HEIGHTS AROUND 2500FT FOR THE MOST PART...BUT THIS MAY
VARY BY AROUND 1000FT THRU THE DURATION OF THE TAF PERIOD.

&&

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

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE HASTINGS NE
344 PM CDT TUE AUG 31 2010

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-
011200-
PHILLIPS-SMITH-JEWELL-ROOKS-OSBORNE-MITCHELL-VALLEY-GREELEY-NANCE-
SHERMAN-HOWARD-MERRICK-POLK-DAWSON-BUFFALO-HALL-HAMILTON-YORK-
GOSPER-PHELPS-KEARNEY-ADAMS-CLAY-FILLMORE-FURNAS-HARLAN-FRANKLIN-
WEBSTER-NUCKOLLS-THAYER-
344 PM CDT TUE AUG 31 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL NEBRASKA AND
PORTIONS OF NORTH CENTRAL KANSAS.

.DAY ONE...TONIGHT.

THUNDERSTORMS ARE POSSIBLE THIS EVENING SOUTH OF A LINE FROM YORK
TO PHILLIPSBURG...ALONG AN ADVANCING COLD FRONTAL BOUNDARY. SEVERE
STORMS ARE POSSIBLE WHICH MAY PRODUCE HAIL TO THE SIZE OF HALF
DOLLARS AND DAMAGING WINDS IN EXCESS OF 60 MPH. LOCALLY HEAVY
RAINFALL IN EXCESS OF AN INCH MAY ALSO OCCUR.

ADDITIONAL THUNDERSTORMS ARE FORECAST DURING THE OVERNIGHT HOURS
ACROSS THE ENTIRE OUTLOOK AREA. A STRONG TO SEVERE STORM MAY OCCUR
AND PRODUCE DIME TO QUARTER SIZE HAIL...AND 50 TO 60 MPH WINDS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THUNDERSTORM CHANCES CONTINUE ACROSS THE OUTLOOK AREA WEDNESDAY
AND WEDNESDAY NIGHT. CONDITIONS WILL AGAIN BE SUPPORTIVE OF SOME
STRONG TO SEVERE THUNDERSTORMS DURING THE AFTERNOON AND EVENING
HOURS. LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY SEVERE
WEATHER THREATS...AND SOME LOCALLY HEAVY RAIN MAY POSE SOME
ADDITIONAL FLOODING CONCERNS.

STRONG NORTHWEST WINDS OF 25 TO 30 MPH AND GUSTS NEAR 40 MPH ARE
FORECAST THURSDAY...FOLLOWING THE PASSAGE OF ANOTHER COLD FRONTAL
BOUNDARY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING FOR LOCATIONS SOUTH
OF A LINE FROM YORK NEBRASKA TO PHILLIPSBURG KANSAS.

&&

MORE INFORMATION MAY BE OBTAINED AT THE FOLLOWING WEB PAGE:
   HTTP://WWW.WEATHER.GOV/HASTINGS  (ALL LOWERCASE)