Special Weather Statement, NWS Pocatello, ID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
156 PM MDT THU JUL 23 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY.
EXPECT SCATTERED SHOWER AND THUNDERSTORM ACTIVITY THIS AFTERNOON
AND EVENING WITH MOIST AIR MASS STILL IN PLACE AND MOISTURE
PUSHING NORTHEAST ON SOUTHWEST FLOW ALOFT AHEAD OF UPPER LEVEL
TROF. ACTIVITY SHOULD DISSIPATE OVERNIGHT AND EXPECT SIMILAR
SCENARIO FRIDAY WITH MORE ISOLATED TO SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS ONCE AGAIN. MODELS DRY IT OUT
SOMEWHAT SATURDAY AND EXPECT MOST ACTIVITY IN THE UPPER SNAKE
HIGHLANDS WITH DRY CONDITIONS EXPECTED MOST EVERYWHERE. HIGH
TEMPERATURES SHOULD BE NEAR OR SLIGHTLY BELOW SEASONAL NORMALS
FRIDAY AND SATURDAY.
GK

.LONG TERM...SUNDAY THROUGH THURSDAY.
DEEP UPPER LEVEL TROF PUSHES EAST ON SHORE FROM THE PACIFIC ALONG
WITH A STRONG COLD FRONT ON SUNDAY WITH WINDS EXPECTED TO INCREASE
AHEAD OF THE FRONT SUNDAY. EXPECT THE THREAT FOR SHOWERS AND
THUNDERSTORMS SUNDAY NIGHT THROUGH MONDAY MAINLY IN THE CENTRAL
MOUNTAINS AND UPPER SNAKE HIGHLANDS. EXPECT MUCH COLDER CONDITIONS
WITH WELL BELOW NORMAL TEMPERATURES MONDAY THROUGH TUESDAY. SHOULD
SEE SOME BREEZY TO WINDY CONDITIONS AS WELL MONDAY BEHIND THE COLD
FRONTAL PASSAGE. IT SHOULD BE DRY ON TUESDAY. UPPER RIDGE BEGINS
TO BUILD TO WEST BY MID WEEK AND EXPECT MUCH WARMER AND CONTINUED
DRY CONDITIONS WEDNESDAY AND THURSDAY.
GK

&&

.AVIATION...SHOWERS AND THUNDERSTORMS BEGINNING TO DEVELOP ACROSS SE
ID ATTM. EXPECT ACTIVITY TO FIRST APPROACH BYI BY 20Z...PIH...IDA
AND SUN BETWEEN 21-22Z. CARRYING VCTS BUT WILL REFINE TIMING AND ADD
TS AS NECESSARY AS CONFIDENCE INCREASES ON TIMING AND LOCATION OF
CONVECTION. ACTIVITY WILL BEGIN TO DIMINISH TO VCSH BY 03-04Z THIS
EVENING...WITH GREATEST CHANCES FOR OVERNIGHT SHOWER ACTIVITY AT PIH
AND IDA. ANY CONVECTION WILL HAVE THE POTENTIAL TO PRODUCE GUSTS IN
THE 25-35 KT RANGE TODAY...OTHERWISE EXPECT SOME AFTERNOON GUSTINESS
TO DEVELOP FOR SNAKE PLAIN SITES ON THE ORDER OF 20 TO 25
KTS...STRONGEST AT IDA. MORE SHOWER AND THUNDERSTORM ACTIVITY
EXPECTED FOR TOMORROW AFTERNOON. VFR CONDITIONS EXPECTED ALL TAF
SITES THROUGH THE PERIOD...ALTHOUGH TEMPORARY REDUCTIONS IN VIS AND
CIGS POSSIBLE IN HEAVIER CONVECTION. NOTE: KSUN
OBSERVATIONS...ESPECIALLY CIG...VIS...AND PRESENT WEATHER MAY BE
UNRELIABLE BETWEEN 03Z AND 13Z DUE TO EQUIPMENT ISSUES. AD/GK

&&

.FIRE WEATHER...A SLOW MOVING LOW PRESSURE SYSTEM WILL CONTINUE TO
ADVANCE EASTWARD ACROSS THE REGION THROUGH TOMORROW...BEFORE
WEAKENING AND LIFTING OUT THROUGH THE COURSE OF THE DAY FRIDAY. THIS
REGION OF LOW PRESSURE WILL COMBINE WITH EXISTING ANOMALOUSLY MOIST
AIR TO PRODUCE WIDESPREAD SHOWERS AND ISOLATED TO SCATTERED
THUNDERSTORMS THIS AFTERNOON AND EVENING...MOST WIDESPREAD OVER
HIGHER TERRAIN. ACTIVITY WILL DIMINISH SOMEWHAT OVERNIGHT WITH A FEW
SHOWERS LINGERING OVER MAINLY SE HIGHLANDS. RENEWED SHOWER AND
THUNDERSTORM ACTIVITY FOR FRIDAY AND SATURDAY AS MOISTURE LINGERS
OVER THE REGION...ALTHOUGH OVERALL COVERAGE BECOMES PROGRESSIVELY
LESS WIDESPREAD EACH DAY...WITH MAINLY ISOLATED SHOWERS AND
THUNDERSTORMS EASTERN HIGHLANDS BY SATURDAY. TEMPERATURES WILL
GRADUALLY WARM AND AFTERNOON HUMIDITY VALUES WILL GRADUALLY DRY ON
SATURDAY AND SUNDAY. BY SUNDAY...A VIGOROUS TROUGH WILL MOVE ONSHORE
OVER THE PACNW AND WILL INCREASE WINDS...WITH GUSTS IN THE 20-30 MPH
POSSIBLE DURING THE AFTERNOON AND EVENING HOURS SUNDAY. THIS
COMBINED WITH MINIMUM RH VALUES APPROACHING THE 15 PERCENT THRESHOLD
IN ZONE 410 MAY NECESSITATE THE NEED FOR A RED FLAG. SHOWER AND
THUNDERSTORM ACTIVITY THEN INCREASES IN COVERAGE FOR SUNDAY NIGHT
THROUGH MONDAY AS A SHARP COLD FRONT SWEEPS EASTWARD THROUGH THE
REGION. GUSTY WINDS EXPECTED TO CONTINUE INTO MONDAY...THOUGH
MOISTURE INCREASES MARKEDLY COMPARED TO SUNDAY. AD/GK

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE POCATELLO ID
1121 PM MDT THU JUL 23 2015

IDZ017-021>023-240615-
EASTERN MAGIC VALLEY ID-SOUTH CENTRAL HIGHLANDS ID-
LOWER SNAKE RIVER PLAIN ID-CARIBOU HIGHLANDS ID-
1121 PM MDT THU JUL 23 2015

...A LINE OF THUNDERSTORMS SOUTH OF MINIDOKA MOVING NORTHEAST
TOWARD AMERICAN FALLS THROUGH 1220 AM MDT...

AT 1117 PM MDT...DOPPLER RADAR WAS TRACKING A LINE OF THUNDERSTORMS
SOUTH OF MINIDOKA...MOVING NORTHEAST AT 30 MPH.

BRIEF MODERATE RAIN...AND GUSTY WINDS TO 35 MPH ARE POSSIBLE WITH
THESE STORMS AS THEY LIFT NORTHEAST TOWARD AMERICAN FALLS THROUGH
1220 PM MDT.

LOCATIONS IMPACTED INCLUDE...
POCATELLO...RUPERT...AMERICAN FALLS...AMERICAN FALLS RESERVOIR...LAKE
WALCOTT...NEELEY...CHUBBUCK...ABERDEEN...INKOM...ROCKLAND...
MINIDOKA...POCATELLO AIRPORT...COLD WATER REST AREA...FORT HALL
BANNOCK PEAK...FORT HALL BANNOCK CREEK LODGE...PORTNEUF GAP...
ACEQUIA...PILAR BUTTE AND MASSACRE ROCKS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THESE STORMS.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4313 11310 4301 11256 4274 11205 4232 11332
      4252 11343 4263 11383
TIME...MOT...LOC 0517Z 232DEG 29KT 4264 11355 4259 11332 4248 11310

HUSTON