Damaging Wind in Nebraska, July 13, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
230 PM CDT FRI JUL 13 2001

...AS ALWAYS...TSRA CHANCES AND THEN LOW CLOUDS THE FCST
CHALLENGES...

LATEST WATER VAPOR IMAGERY INDICATES WEAK SHORT WAVE TROFS ROUNDING
THE UPPER RIDGE THAT HAS BEEN IN PLACE FOR THE LAST FEW WEEKS. MORE
SIGNIFICANT FEATURE IN THE DAKOTAS. VISIBLE IMAGERY/KLNX 88D SHOWS
WEAK CONVECTION IN SOUTHERN DAWES COUNTY...BUT HAVING A HARD TIME
SUSTAINING. AT THE SFC...WEAK TROF EVIDENT BY CALM WINDS IN THE
NWRN PANHANDLE...AND OUTFLOW FROM KS MCS WAS SEEN EARLIER HEADING N
INTO THAT SAME VICINITY. MSAS SHOWS BEST PERSISTENT LOW LEVEL
MOISTURE CONVERGENCE BETWEEN THE SRN BLACK HILLS AND VTN...AND
FURTHER W INTO WY/CO.

12Z ETA HAS DONE A PRETTY GOOD JOB LATELY IN DEFINING SMALLER AREAS
OF CONVECTION...WITH THE 18Z RUN NOT SO MUCH. IN THE LARGE SCALE...
MODELS IN PRETTY GOOD AGREEMENT WITH MOST OF THE FEATURES. FWC
GUIDANCE LOOKS MUCH CLOSER TO REALITY THAN THE TOO COOL MAV.

WOULD EXPECT CONVECTION IN WRN/NRN PANHANDLE TO BECOME A LITTLE
BETTER ORGANIZED THRU 02Z OR SO...BUT THEN SHOULD DIE OFF
AFTER/NEAR SUNSET. WITH LOW LEVEL FLOW WEAK...BEST LOW
LEVEL CIRCULATIONS WERE LIKELY AIDED BY DIFFERENTIAL HEATING
BOUNDARY SETUP BY MORNING CLOUDS. THEREFORE...AS THE ATMOSPHERE
BECOMES A LITTLE MORE HOMOGENEOUS TWD SUNSET...STORMS SHOULD GO
AWAY WITH LITTLE IN THE WAY OF UPPER FORCING AND NO LOW LEVEL JET TO
SUSTAIN THEM. SOME CONCERN ABOUT CONVECTION IN THE HIGH COUNTRY
MOVING INTO THE WRN CWA...BUT BELIEVE THEYLL FADE BEFORE THEY GET
HERE BECAUSE OF THE SAME REASONS. SO INCLUDED LOW POPS IN THE W.
DRIER/COOLER LOW-MID LEVEL AIR HAS WORKED INTO CWA SO NO POPS
INCLUDED THERE.

FOR SATURDAY...ETA LOW LEVEL RH PROGS NOT AS BULLISH WITH MOISTURE
AS IN PREVIOUS DAYS AND WITH 850 MB WINDS A LITTLE MORE SWRLY...
THINK FOG/LOW CLOUDS WONT BE AS WIDESPREAD...AND INCLUDED ONLY IN
AND NEAR THE PLATTE RIVER VALLEY. SO THAT SHOULD LEAVE BETTER
SUNSHINE POSSIBILITIES FOR THE CWA BY AFTERNOON. A MORE SUBSTANTIAL
SHORT WAVE TROF TOPS THE RIDGE BY EVENING AND SHOULD GENERATE MORE
WIDESPREAD STORMS WHICH...BECAUSE OF COOL AIR ALOFT AND HENCE
STEEPER LAPSE RATES...SHOULD SUSTAIN THEMSELVES (SIMILAR TO MODEL
SOLUTIONS) AND MAKE IT INTO THE WRN HALF OF THE CWA DURING THE
EVENING/OVERNIGHT. LEFT ERN MOST CWA DRY...SINCE CONVECTIVE COMPLEX
LIKELY WONT MAKE IT THAT FAR EAST. CONVECTIVE REMNANTS WILL LAST
INTO SUNDAY IN THE ERN CWA...SO BACKED OFF MAXES A LITTLE THERE DUE
TO CLOUD COVER. ETA HAS ANOTHER CONVECTIVE COMPLEX DEVELOPING IN THE
PANHANDLE LATE IN THE DAY SUNDAY...AND IF SUNSHINE DEVELOPS...
AIRMASS COULD RECOVER IN TIME. HOWEVER...TIMING OF CONVECTION
ALWAYS A TRICK SO I DIDNT GO OVERBOARD ON POPS JUST YET.

IN THE EXTENDED...SAME OL PATTERN THRU DAY 7 BASED ON A GLANCE AT
MEDIUM RANGE MODELS AND NCEP EMSEMBLES. RIDGE DOES TAKE A BIT OF A
MORE NEG TILT (NOT REALLY NEG...JUST LESS POSITIVE) THROUGH THE
WEEK AND THINK FOR THE MOST PART...WE SHOULD SEE THE BETTER
CONVECTIVE ACTIVITY DEVELOPING N OF CWA...HOWEVER WRN FRINGES COULD
GET IN ON THE ACTION. HATE TO FLIP-FLOP ON PRECIP TIMING WITH
CONVECTION SO LEFT WORDING PRETTY MUCH AS IT WAS.

.LBF...NONE.

JWS