Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 292345 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
645 PM CDT WED JUL 29 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 238 PM CDT WED JUL 29 2015

TODAY AND TONIGHT...WEAK HIGH PRESSURE BUILDS TO THE EAST OF THE
FORECAST AREA THIS EVENING AND OVERNIGHT...ALLOWING SOUTHERLY FLOW
TO PREVAIL.  TEMPERATURES AND LOWER TROPOSPHERIC MOISTURE WILL
INCREASE...HOWEVER ANOTHER NIGHT OF BELOW AVERAGE TEMPERATURES ARE
FORECAST AS SKIES WILL REMAIN MOSTLY CLEAR AND THE RETURN FLOW WILL
BE RELATIVELY WEAK INITIALLY.  A GENERAL BLEND OF THE NUMERICAL
GUIDANCE WITH THE PREVIOUS FORECAST SUGGESTS MID 50S ACROSS THE
REGION.  LOWER 50S REMAIN POSSIBLE ACROSS THE HIGHER TERRAIN OF
SHERIDAN AND GARDEN COUNTIES WHERE LAST NIGHT TEMPERATURES FELL WELL
INTO THE 40S.

THETA RICH AIR REMAIN SOUTH OF THE FORECAST AREA THURSDAY...WITH THE
BEST FOCUS FOR STORMS SOUTH ACROSS SE COLORADO...WILL KEEP THE
FORECAST DRY THURSDAY.  H85 TEMPS WILL INCREASE TO THE 26-28C RANGE
ON THURSDAY...THIS WILL PROMOTE HIGHS BACK INTO THE UPPER 80S TO
LOWER 90S ACROSS THE FORECAST AREA...WHICH IS NEAR NORMAL.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 238 PM CDT WED JUL 29 2015

THURSDAY NIGHT THROUGH SATURDAY...THE NAM AND OTHER MODELS CONTINUE
TO SHOW SOME SORT OF CONVECTION DEVELOPING AROUND 21Z FRIDAY AFTN.
THE NAM BACKED OFF A BIT ON THE MLCAPE...STILL NEAR 2000J/KG BUT
AMBIENT PWAT IS NEAR 1.33 INCHES AND K INDICES ARE WELL OVER 40C.
WINDS ALOFT AT THE 300MB LEVEL REMAIN STRONG AT 60 TO 70KT AND
BULK SHEAR OF 30KT IS CALCUATED TO 400 MB. SO SOME SEVERE WEATHER
COULD DEVELOP. POPS ARE LIMITED TO 30 PERCENT FOR THIS EVENT. WE
NOTE THE HODOGRAPH IS HIGHLY LINEAR AND LONG AT THAT SUGGESTING
STORM SPLITTING AND MULTICELLS.

THE MOISTURE IN THE NAM IS NOT SUSPECT BUT APPEARS TO BE FORCED BY
OUR OLD FRIEND 700-500MB FRONTOGENESIS. TEMPS ALOFT ARE COLD WITH
H700MB TEMPERATURES NEAR OR BELOW 10C AND A FREEZING LEVEL LESS THAN
11KFT AGL WHICH COULD SUPPORT JAGGED HAIL. STORM DEVELOPMENT APPEARS
MOST LIKELY ALONG OR NEAR NEBRASKA HIGHWAY 2.

SOMETHING SIMILAR MAY HAPPEN SATURDAY BUT A BIT FARTHER NORTH. ONCE
AGAIN MOISTURE APPEARS TO BE POOLING ALOFT AT THE 700-500MB LEVEL
BUT THIS FEATURE IS UNDERWAY BY 12Z SATURDAY. POPS NEAR 30 PERCENT
ARE IN PLACE FROM 12Z SATURDAY ONWARD. WE NOTE THE NAM SHOWS THE
STORMS DEVELOPING DURING THE PEAK HEATING PERIOD AND MUCH FARTHER
WEST...ACROSS THE BLACK HILLS AND PINE RIDGE.

HIGHS THURSDAY AND FRIDAY RISE TO AROUND 90 AS H850MB TEMPERATURES
RISE INTO THE MID TO UPPER 20S C.

SATURDAY NIGHT THROUGH WEDNESDAY...THE BEST CHANCE OF RAIN IS
TUESDAY AND THE ECM IS LEADING THE WAY. THE GFS IS A WARMER SOLN AND
CAPS THE FORECAST AREA FORCING THE RAIN EAST OF THE FCST AREA. THE
GEF MODEL IS ACTUALLY FASTER THAN THE ECM/GFS BUT SUGGESTS THE SAME
BASIC IDEA AS THE GFS PLACING BEST CHANCE ALONG THE MISSOURI RIVER
AND EAST. THE ECM IS THE FARTHEST WEST. OTHERWISE JUST ISOLATED
POPS ARE EXPECTED SUNDAY AND MONDAY.

HIGHS IN THE 90S ARE EXPECTED SUNDAY AND MONDAY AND A STRONG CAP
WILL BE IN PLACE WITH H700MB TEMPERATURES RISING TOWARD 15C MONDAY.
THE ECM THEN BRINGS A SOLID SHORTWAVE THROUGH THE NRN PLAINS SETTING
OFF THE STORMS. THE TOASTY GFS CONTINUES TO WARM H700MB TEMPERATURES
TOWARD 17C WEDNESDAY WHILE THE ECM PLUGS COOLER AIR BEHIND THE
THUNDERSTORMS.

THE RAIN CHANCES ARE 30 PERCENT FOR TUESDAY. THE ECM SHOWS VERY
MODEST WINDS AT 300MB NEAR 30KT SUGGESTING MORE OF HEAVY RAIN/WIND
SITUATION VERSUS SUPERCELL.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 641 PM CDT WED JUL 29 2015

VISUAL FLIGHT RULES OVER WESTERN NEBRASKA THROUGH THURSDAY WITH
SURFACE HIGH PRESSURE OVER HEAD AND LIGHT AND VARIABLE WINDS
EXPECTED.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...JACOBS
LONG TERM...CDC
AVIATION...POWER


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