Severe Thunderstorm Warning 99, NWS Pocatello, ID

EASTERN IDAHO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
140 PM MDT THU SEP 11 1997

KSFX 88D INDICATING A LINE OF TSTMS MOVING INTO THE MAGIC VALLEY...
AND FURTHER STORMS STARTING TO POP IN THE SNAKE PLAINS WHERE IT HAS
BEEN RELATIVELY CLEAR THIS MORNING.  THE LATER STORMS HAVE THE BEST
POTENTIAL FOR SEVERE...ALTHOUGH IT REMAINS LIKELY MOST STORMS WILL BE
ONLY HEAVY RAIN PRODUCERS.  WINDS REMAIN FROM THE NORTH AT 10 TO 20
MPH ACROSS MUCH OF THE PLAINS AND THERE IS THE RISK OF A CONVERGENCE
ZONE GENERATING ACROSS THE SOUTHERN SNAKE PLAINS WHEN THESE WINDS
COLLIDE WITH THE WESTERLY WINDS ASSOCIATED WITH THE APPROACHING LINE
AND FRONT.  DYNAMICS LOOK SOLID FOR STRONG TO SEVERE CONVECTIVE TO
CONTINUE INTO THE EARLY EVENING HOURS WITH THE PASSAGE OF THE UPPER
PORTION OF THE FRONT ASSOCIATED WITH THE LINE OF TSTMS...WHILE THE
SURFACE FRONT LAGS BEHIND AND WILL CONTINUE GENERATION OF CONVECTION
INTO THE EVENING. ...PV MAX...H3 JET...DIFLUENCE AND CAA ALOFT.
STRONG STORMS STILL SUPPORTED BY PV MAXIMA...H3 JET...DIFLUENCE ALOFT
ALL IN A HIGH CAPE ENVIRONMENT...RICH H7/H5 THETA-E ADVECTION...AND
MODEST H8-H4 SHEAR.  AFTER MIDNIGHT EXPECT CLEARING AS A DRIER AND
STABLE AIRMASS OVERSPREADS EASTERN IDAHO.  SEASONAL TEMPERATURES WILL
BE ESTABLISHED FOR THE REMAINDER OF THE PERIOD AS ADDITIONAL CAA
REINFORCES THE INITIAL SHOT OF COLD AIR.  COLD AIR ALOFT WILL CREATE
ENOUGH INSTABILITY FRIDAY AFTERNOON FOR SOME CLOUDS AND A CHANCE OF
SHOWERS PARTICULARLY OVER THE EASTERN HIGHLANDS.  FRIDAY NIGHT WILL
SEE COLD TEMPS WITH POSSIBLE FREEZING TEMPS NORTH OF IDA.  GUIDANCE
APPEARS TOO WARM ON THE HIGHS.  TSC
.WSR88D KSFX...VCP21 OPERATIONAL.

IDA BU 045/072 040/075 040 07700
PIH BU 048/075 044/079 044 07700