Severe Thunderstorm Warning 149, NWS Hastings, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
336 PM CDT MON AUG 20 2007

.SHORT TERM...STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ARE THE PRIMARY FORECAST CONCERN. A VERY MOIST AND
UNSTABLE AIRMASS IS IN PLACE ACROSS THE REGION WITH SFC BASED CAPE
VALUES OF OVER 7000 J/KG ACROSS PORTIONS OF OUR CWA. DEEP LAYER
SHEAR IS ALSO MORE IMPRESSIVE TODAY WITH 0 TO 6KM SHEAR VALUES OF
OVER 40 KTS THANKS TO A SHORT WAVE THAT IS TRACKING ACROSS THE
STATE. A SFC BOUNDARY IS ALSO FIGURING INTO THE EQUATION AND IS
RUNNING FROM NORTHEAST TO SOUTHWEST RIGHT ACROSS THE CENTER OF OUR
CWA. STRONG TO SEVERE THUNDERSTORMS ARE ALREADY FIRING ALONG THIS
BOUNDARY AND CAN BE EXPECTED TO EXPAND IN COVERAGE AND INTENSITY
THIS EVENING WHILE SLIDING TOWARDS THE SOUTHEAST. THEREFORE...THE
GREATEST THREAT OF SEVERE WEATHER WILL BE FOCUSED ACROSS SOUTHERN
AND EASTERN PORTIONS OF OUR CWA. THERE IS ENOUGH SHEAR AND
INSTABILITY ESPECIALLY ACROSS EASTERN NEBRASKA ZONES TO MAKE
ISOLATED TORNADOES A POSSIBILITY ALONG WITH THE THE USUAL LARGE
HAIL AND HIGH WIND THREATS.

MOST THUNDERSTORMS THIS EVENING SHOULD SLIDE OUT OF OUR CWA BY
MIDNIGHT. THERE COULD STILL BE AN ISOLATED THUNDERSTORM DURING THE
EARLY MORNING HOURS DUE TO THE LOW LEVEL JET. SFC BOUNDARY WILL
REMAIN ACROSS PORTIONS OF OUR CWA TOMORROW AND WILL LIKELY
INTERACT WITH OLD OUTFLOW BOUNDARIES TO GIVE OUR CWA ANOTHER
SHOT OF PRECIPITATION ESPECIALLY TOMORROW AFTERNOON INTO TOMORROW
EVENING.

.LONG TERM...12Z WEDNESDAY THROUGH MONDAY. FORECAST CONCERNS INCLUDE
PRECIPITATION CHANCES THROUGH FRIDAY AND THEN TEMPERATURES IN THE
LATTER HALF OF THE PERIOD.

AN ACTIVE AND FAIRLY WET PERIOD LOOKS TO BE SHAPING UP FOR THE AREA
DURING THE WEDNESDAY THROUGH FRIDAY TIMEFRAME. A SURFACE FRONT
STALLS ACROSS THE REGION WHILE PERIODIC SHORTWAVES EJECT OUT OF A
BROAD LOW-AMPLITUDE UPPER TROUGH ACROSS THE WESTERN CONUS AND RIDE
ACROSS THE CENTRAL PLAINS. THE GULF IS WIDE OPEN DURING THIS
TIME...WITH SOUTHERLY SURFACE WINDS AROUND A SURFACE RIDGE CENTERED
OVER THE SOUTHEAST CONUS ADVECTING MOISTURE RICH AIR NORTHWARD.
DIFFICULT IF NOT IMPOSSIBLE TO NAIL DOWN SHORTWAVE TIMING AND
PRECISE BOUNDARY PLACEMENT GIVEN CONVECTIVE INFLUENCES THIS FAR
OUT...BUT RAIN CHANCES LOOK GOOD FOR THE AREA AS A WHOLE WEDNESDAY
INTO FRIDAY...WITH WEDNESDAY NIGHT AND THURSDAY NIGHT LOOKING LIKE
THE BEST PERIODS FOR WIDESPREAD PRECIPITATION. THE LLJ KICKS UP TO
40 TO 45 KTS BOTH NIGHTS WITH GOOD MOISTURE CONVERGENCE ACROSS THE
CWFA. HEAVY RAINFALL IS POSSIBLE PARTICULARLY WEDNESDAY NIGHT AND
THURSDAY NIGHT...WHICH COULD PRODUCE SOME FLOODING PROBLEMS. THE
ATMOSPHERE ALSO STAYS SUFFICIENTLY UNSTABLE WEDNESDAY AND THURSDAY
TO SUPPORT SOME STRONG OR SEVERE STORMS DURING THE AFTERNOON AND
EVENING HOURS. ALSO ADEQUATE DEEP LAYER SHEAR BOTH DAYS TO SUPPORT
SOME STRONG TO SEVERE CONVECTION.

PRECIP CHANCES CONTINUE ON FRIDAY AS THE MAIN UPPER TROUGH AXIS
SLIDES ACROSS...WHICH FINALLY BEGINS TO PUSH THE STALLED SURFACE
FRONT SOUTH. AS IT DOES SO...PRECIP CHANCES END FROM NORTH TO SOUTH
FRIDAY NIGHT. THE FRONT PUSHES SUFFICIENTLY FAR SOUTH BY SATURDAY TO
DRY THINGS OUT WHILE HEIGHTS ALOFT BUILD SLIGHTLY IN BETWEEN
DEPARTING TROUGH AND NEXT SYSTEM MOVING INTO THE PAC NW. SATURDAY
LOOKS LIKE A PLEASANT LATE AUGUST DAY AS BOTH THE GFS AND ECMWF SHOW
H85 TEMPS IN THE MID TO UPPER TEENS BEHIND THE FRONT AND EASTERLY
SURFACE WINDS...WHICH WILL SPELL COOLER CONDITIONS THAN WE/VE SEEN
IN A WHILE. LOWERED TEMPS A FEW DEGREES BUT THEY STILL MAY BE A TAD
HIGH. TEMPS THEN BEGIN TO REBOUND SUNDAY AND MONDAY AS THE SURFACE
HIGH SHIFTS EAST AND RETURN FLOW ENSUES. NEXT SYSTEM LOOKS TO AFFECT
THE AREA LATE MONDAY INTO TUESDAY AS AN UPPER LOW SLIDES EAST ACROSS
SOUTHERN CANADA AND THE NORTHERN TIER STATES...SENDING A FRONT SOUTH
INTO THE PLAINS.

AVIATION...18Z TAF...THE PRIMARY AVIATION CONCERN WILL CENTER AROUND
WIND SHIFTS...WITH SOUTHERLY WINDS EARLY THIS AFTERNOON BECOMING
SOUTHWEST BY MID AFTERNOON AND NORTHERLY BY AROUND 7 TO 8PM. WINDS
OVERNIGHT WILL THEN SHIFT FROM NORTHERLY TO MORE EASTERLY AFTER
MIDNIGHT AND EVENTUALLY BACK OUT OF THE SOUTHEAST TOMORROW
MORNING. THUNDERSTORM CHANCES WILL BE BEST NORTHEAST OF KGRI WITH
JUST THE SLIGHTEST CHANCE OF A THUNDERSTORM AT KGRI. AN ADDITIONAL
CONCERN WILL BY LOW CLOUDS MOVING IN LATER TONIGHT. EXPECT AT
LEAST SCATTERED IF NOT BROKEN LOW CLOUDS AFTER MIDNIGHT TONIGHT
WITH POSSIBLE VISIBILITY REDUCTIONS ESPECIALLY NEAR DAWN.

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

WESELY/KB

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE HASTINGS NE
438 PM CDT MON AUG 20 2007

NEZ040-041-047>049-062>064-074>077-084>087-211200-
GREELEY-NANCE-HOWARD-MERRICK-POLK-HALL-HAMILTON-YORK-KEARNEY-
ADAMS-CLAY-FILLMORE-FRANKLIN-WEBSTER-NUCKOLLS-THAYER-
438 PM CDT MON AUG 20 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL NEBRASKA
PRIMARILY ALONG AND EAST OF HIGHWAY 281.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON INTO TONIGHT ALONG A SURFACE FRONT LOCATED ACROSS SOUTH
CENTRAL NEBRASKA. THESE STORMS WILL BE CAPABLE OF PRODUCING HAIL
TO SIZE OF TENNIS BALLS...WIND GUSTS IN EXCESS OF 60 MPH...AND
ISOLATED TORNADOES. IN ADDITION...LOCALIZED HEAVY RAINFALL MAY
RESULT IN AREAS OF FLASH FLOODING.

INTENSE HEAT CAN ALSO BE EXPECTED THIS AFTERNOON AND EVENING WITH
HEAT INDEX VALUES OF 100 TO 115.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

CURRENT TRENDS INDICATE THE OUTLOOK AREA CAN EXPECT SEVERAL DAYS
OF AT LEAST SCATTERED THUNDERSTORMS...ESPECIALLY DURING THE
EVENING AND NIGHTTIME HOURS. THE THUNDERSTORMS WILL BE MOST LIKELY
FROM TUESDAY THROUGH FRIDAY.

THUNDERSTORMS TUESDAY EVENING INTO TUESDAY NIGHT MAY BE STRONG TO
SEVERE...CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS...AND HEAVY
RAIN. THE RISK FOR LOCALLY HEAVY RAINS WILL CONTINUE THROUGH
THURSDAY...AND MAY RESULT IN FLOODING ISSUES FOR SOME AREAS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED THIS AFTERNOON AND EVENING.

&&

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

KSZ005>007-017>019-211200-
PHILLIPS-SMITH-JEWELL-ROOKS-OSBORNE-MITCHELL-
438 PM CDT MON AUG 20 2007

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON INTO TONIGHT ALONG A SURFACE FRONT LOCATED ACROSS NORTH
CENTRAL KANSAS. THE PRIMARY SEVERE WEATHER THREAT WILL BE HAIL TO
THE SIZE OF TENNIS BALLS AND WIND GUSTS IN EXCESS OF 60 MPH.
HOWEVER...THERE IS ALSO THE POSSIBILITY OF AN ISOLATED TORNADO.
IN ADDITION...LOCALIZED HEAVY RAINFALL MAY RESULT IN AREAS OF
FLASH FLOODING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

CURRENT TRENDS INDICATE THE OUTLOOK AREA CAN EXPECT SEVERAL DAYS
OF AT LEAST SCATTERED THUNDERSTORMS...ESPECIALLY DURING THE
EVENING AND NIGHTTIME HOURS. THE THUNDERSTORMS WILL BE MOST LIKELY
FROM TUESDAY THROUGH FRIDAY.

THUNDERSTORMS TUESDAY EVENING INTO TUESDAY NIGHT MAY BE STRONG TO
SEVERE...CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS...AND HEAVY
RAIN. THE RISK FOR LOCALLY HEAVY RAINS WILL CONTINUE THROUGH
THURSDAY...AND MAY RESULT IN FLOODING ISSUES FOR SOME AREAS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED THIS AFTERNOON AND TONIGHT.

&&

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

NEZ039-046-060-061-072-073-082-083-211200-
VALLEY-SHERMAN-DAWSON-BUFFALO-GOSPER-PHELPS-FURNAS-HARLAN-
438 PM CDT MON AUG 20 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL NEBRASKA
PRIMARILY WEST OF HIGHWAY 281.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON AND
TONIGHT. THE PRIMARY THREAT WILL BE HAIL TO THE SIZE OF NICKELS
AND WIND GUSTS TO 50 MPH.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

CURRENT TRENDS INDICATE THE OUTLOOK AREA CAN EXPECT SEVERAL DAYS
OF AT LEAST SCATTERED THUNDERSTORMS...ESPECIALLY DURING THE
EVENING AND NIGHTTIME HOURS. THE THUNDERSTORMS WILL BE MOST LIKELY
FROM TUESDAY THROUGH FRIDAY.

THUNDERSTORMS TUESDAY EVENING INTO TUESDAY NIGHT MAY BE STRONG TO
SEVERE...CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS...AND HEAVY
RAIN. THE RISK FOR LOCALLY HEAVY RAINS WILL CONTINUE THROUGH
THURSDAY...AND MAY RESULT IN FLOODING ISSUES FOR SOME AREAS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION SHOULD NOT BE NEEDED THIS AFTERNOON INTO TONIGHT.

&&

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

WESELY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
411 PM CDT MON AUG 20 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0408 PM     TSTM WND GST     6 NNE KENSINGTON        39.85N 98.99W
08/20/2007  E60 MPH          SMITH              KS   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
427 PM CDT MON AUG 20 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0415 PM     HAIL             1 W GUIDE ROCK          40.07N 98.35W
08/20/2007  E0.88 INCH       WEBSTER            NE   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
439 PM CDT MON AUG 20 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0434 PM     HAIL             NELSON                  40.20N 98.07W
08/20/2007  E1.00 INCH       NUCKOLLS           NE   LAW ENFORCEMENT

&&

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HASTINGS NE
447 PM CDT MON AUG 20 2007

NEZ040-202230-
GREELEY-
447 PM CDT MON AUG 20 2007

...THE NATIONAL WEATHER SERVICE IN HASTINGS HAS ISSUED A SIGNIFICANT
WEATHER ALERT FOR GREELEY COUNTY...

AT 445 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES NORTH OF SPALDING...OR 30 MILES NORTHEAST
OF ORD...AND MOVING SOUTHEAST AT 15 MPH.

* THE THUNDERSTORM WILL BE NEAR...
  SPALDING BY 510 PM CDT

PENNY TO NICKEL SIZE HAIL...AND WINDS AROUND 50 MPH ARE EXPECTED WITH
THIS STORM.

BE PREPARED TO TAKE SHELTER IN THE EVENT THESE STORMS INTENSIFY AND
BECOME SEVERE, OR A WARNING IS ISSUED BY THE NATIONAL WEATHER
SERVICE.

SB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
452 PM CDT MON AUG 20 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     TSTM WND GST     1 E LAWRENCE            40.29N 98.24W
08/20/2007  E60 MPH          NUCKOLLS           NE   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
457 PM CDT MON AUG 20 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0456 PM     HAIL             1 S DEWEESE             40.34N 98.14W
08/20/2007  E1.00 INCH       NUCKOLLS           NE   STORM CHASER

&&