Severe Thunderstorm Warning 170, NWS Hastings, NE

SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
240 PM CDT FRI JUL 19 2001

HEAT AND HEAVY RAIN CHANCES...WITH THE THREAT OF SEVERE ONCE AGAIN
THE PRIMARY CONCERN.

PERSISTENCE IS THE NAME OF THE GAME THROUGH FRIDAY...WITH A SLIGHT
SHIFTING OF STORM THREAT TO THE NORTH TODAY...AND A LITTLE FURTHER
NORTH TOMORROW.

VERY WARM AND MOIST NEAR SURFACE AND UPPER LEVELS TODAY...WITH A
SOMEWHAT DRIER INTRUSION AROUND H7...AND TWO LOW PRESSURE
CENTERS...ONE OVER WESTERN NE AND ANOTHER OVER OVER SOUTHEASTERN CO
THAT HAVE NEARLY STATIONARY BOUNDARIES THAT STRETCH TO THE EAST FROM
THEM...WILL HELP FOCUS CONVECTIVE ENERGY TODAY. CONVECTIVE
TEMPERATURES WILL LIKELY BE REACHED NEAR SOUTHERN AND WESTERN
PORTIONS OF OUR CWA BY LATE AFTERNOON. AN UPPER LEVEL SHORTWAVE NEAR
SOUTHEASTERN COLORADO IS DUE TO ARRIVE BETWEEN 4 AND 6 PM...AND WILL
ENHANCE ALREADY VERY UNSTABLE CONDITIONS...LIKELY MAKING IT EASIER
TO BREAK THE CAP. DIRECTIONAL SHEAR PROFILES AND THE PROXIMITY TO
40+ KT UPPER JET SUPPORTS SUPERCELL FORMATION WITH SEVERE
WIND...HAIL...AND A FEW TORNADOES POSSIBLE THROUGH LATE EVENING.
AFTERNOON MID LEVEL CAPES BETWEEN 3500 AND 5000 SEEM REASONABLE
GIVEN SET UP. LIFTED INDICES GREATER THAN -8 WILL ALSO RULE. DEW
POINTS OVER ENTIRE CWA RANGE FROM UPPER 60S TO MID 70S. CURRENT PICS
FROM SPACE SHOW MCS OVER NORTHERN MS BREAKING APART THIS
AFTERNOON...HOWEVER VORT MAX AND MOISTURE KICKED WESTWARD FROM
SYSTEM IS NOW GETTING CAUGHT IN UPPER FLOW AND IS ROTATING TOWARD
OUR CWA. ALSO WEAK SHORTWAVE ENERGY NOW ENTERING NORTHWESTERN KA MAY
AID IN BREAKING CAP FOR FIRST SIGNS OF CONVECTION BY 3 OR 4 PM. ALSO
VIS IS SHOWING SURFACE BOUNDARY BECOMING MORE DEFINED FROM EAST
CENTRAL CO...INTO SOUTH CENTRAL NE. LOOKING ALONG THIS LINE FOR
FIRST INDICATIONS.

OTHER THAN SEVERE POTENTIAL EARLY ON...CONCERNED ABOUT POSSIBLE
FLASH FLOODING OVER OUR WESTERN KA COUNTIES AND EXTREME SOUTHEASTERN
NE COUNTIES. LARGE AMOUNTS OF PRECIP...2-4 INCHES OVER THAT LAST 24
HRS...WITH THE POSSIBILITY OF MORE HEAVY RAIN TONIGHT...ESPECIALLY
AFTER NOCTURNAL LLJ RETURNS LATE THIS EVENING...PROVIDING FOCUS FOR
ANOTHER STORM COMPLEX TO FORM...AND PROPAGATE THE STORMS TO THE EAST
SOUTHEAST...AFTER HAVING STARTED OUT MOVING TO THE NORTHEAST. AT ANY
RATE...HEAVY RAIN WILL LIKELY RULE AFTER MIDNIGHT AND OVER AREAS
ALONG AND SOUTH OF I80. TYPICAL AMOUNTS UNDER THE RAIN CANOPY OF THE
MCS WILL RANGE FROM 1 TO 2 INCHES IN A 2 TO 3 HOUR PERIOD WHILE 4 TO
6 INCH TOTALS OVER SOME AREAS NEAR THE KA/NE BORDER CAN NOT BE RULED
OUT. HEAVY RAINS OVER THE S AND SE PORTION OF THE CWA LAST NIGHT HAS
LEAD TO COORDINATION WITH TOP AND OMA AND WILL PROBABLY FOLLOW WITH
ISSUANCE OF FLASH FLOOD WATCH AROUND 4 PM FOR TONIGHT AND OVERNIGHT
FOR SMITH...OSBORNE...JEWEL...AND MITCHELL COUNTIES IN KANSAS...AND
NUCKOLLS AND THAYER COUNTIES IN NEBRASKA.

IN THE FUTURE...FOR FRIDAY I THINK PERSISTENCE IS ONCE AGAIN THE
NAME OF THE GAME...HOWEVER WILL ONLY KEEP 20 POPS FOR SOUTHERN 3
QUARTERS OF CWA...WITH 30S FOR NORTHERN PORTION...AS WARM FRONT
BOUNDARY MOVES A BIT MORE NORTHWARD. LOOKS TO BE MOSTLY DRY ON SAT
THOUGH...WITH RIDGE AND MOISTURE FURTHER NORTH. FOR THE FUTURE
FUTURE...AM GOING WITH CHANCE OF TSTORMS FROM SUN THRU THURS OVER
MOST OF THE CWA...AS RIDGE GETS BEAT DOWN AND FLATTENED
MORE...ALLOWING DISTURBANCES TO ROTATE THROUGH FURTHER SOUTH.
COOLING TEMPS ALSO BY MID WEEKS BECAUSE OF THIS...PROBABLY AT LEAST
10 DEGREES.

.GID...HEAT ADVISORY TONIGHT AND FRIDAY KSZ005>007-017>019.
.GID...FLASH FLOOD WATCH TONIDGHT KSZ006-007-018-019-NEZ086-087.

JB