Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 280857
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
357 AM CDT THU AUG 28 2014

.SYNOPSIS...
ISSUED AT 355 AM CDT THU AUG 28 2014

H5 ANALYSIS FROM EARLIER THIS EVENING HAD A NICE CLOSED LOW OVER
SOUTH CENTRAL WYOMING WITH A TROUGH EXTENDING SWD INTO NEW
MEXICO. WV IMAGERY AS OF 07Z TONIGHT HAS THIS FEATURE SOUTHWEST
OF LARAMIE WYOMING. A STRONG SHORTWAVE WAS NOTED OVER SWRN SD AS
WELL. OTHER H5 FEATURES NOTED OVER NOAM...INCLUDED STRONG LOW
PRESSURE OVER THE EASTERN ALEUTIANS OF ALASKA...HIGH PRESSURE OFF
THE SRN CA COAST AS WELL AS A DECENT NRN STREAM EXTENDING ACROSS
SRN CANADA. WV IMAGERY AS OF 07Z HAS A NICE PLUME OF SWRLY
MONSOON MOISTURE EXTENDING FROM SERN NEW MEXICO INTO CENTRAL AND
EASTERN NEBRASKA. FURTHER WEST...DRIER AIR HAS BEGUN TO WORK INTO
EASTERN COLORADO AND AT PRESENT IS APPROACHING FAR SWRN NEBRASKA.
MODERATE TO HEAVY RAIN HAD FALLEN ACROSS PORTIONS OF SOUTHWESTERN
NEBRASKA EARLIER THIS EVENING. RADAR ESTIMATES WERE HEAVIEST OVER
PERKINS...KEITH AND ARTHUR COUNTIES WERE 2 TO 5 INCHES OF RADAR
ESTIMATED RAINFALL OCCURRED. ATTM...THE HEAVIEST RAIN FELL OVER
SWRN ARTHUR AND NORTHWESTERN KEITH COUNTY...AS WELL AS PORTIONS
OF FAR WESTERN AND FAR EASTERN PERKINS COUNTY. A FLOOD ADVISORY
WAS IN EFFECT FOR PERKINS AND KEITH COUNTY AND WAS EXPIRED AT 330
AM CDT. AS OF 3 AM CDT...UNDER CLOUDY SKIES...TEMPERATURES RANGED
FROM 60 AT OGALLALA TO 69 AT BROKEN BOW AND ONEILL.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT THU AUG 28 2014

THE MAIN FORECAST CHALLENGE OVER THE NEXT 24 HOURS IS RAIN
CHANCES AND THE CONTINUED THREAT FOR HEAVY RAIN...ESPECIALLY
TODAY IN THE EASTERN CWA. AS MENTIONED EARLIER...WV IMAGERY ATTM
HAS AN AREA OF MID LEVEL DRYING OVER EASTERN COLORADO. THIS AREA
IS EXPECTED TO PUSH INTO SWRN...THEN WESTERN PORTIONS OF THE
FORECAST AREA THROUGH THIS MORNING. EAST OF THIS
DRYING...ABUNDANT SUB TROPICAL MOISTURE WILL CONTINUE TO PUSH
INTO CENTRAL AND EASTERN NEBRASKA FROM THE SWRN US WITH PWATS OF
GREATER THAN 1.5 INCHES EAST OF HIGHWAY 183. WEST OF THIS
ROUTE...PWATS DROP TO 1 TO 1.5 INCHES DUE TO THE MID LEVEL DRYING
PER WV IMAGERY. THIS WILL DECREASE PCPN CHANCES THIS MORNING IN
THE WESTERN CWA. DID NOT TOTALLY ELIMINATE PCPN HOWEVER AS NO CAP
IS PRESENT ACROSS THE AREA TODAY. ANY BREAKS IN CLOUD COVER WE DO
SEE THIS MORNING WILL QUICKLY FILL WITH CLOUDS AND ISOLATED
INSTABILITY SHRAS BY LATE MORNING. BY THIS AFTERNOON...INCREASED
CHANCES FOR PRECIP WILL BE IN THE EAST WHERE A DEEP PLUME OF
MOISTURE EXISTS...AS WELL AS WEAK ISENTROPIC LIFT. IN ADDITION TO
PCPN CHANCES IN THE EAST...THE THREAT FOR SHRAS WILL INCREASE IN
THE WEST THIS AFTERNOON AS THE MAIN UPPER LEVEL LOW EJECTS INTO
WRN NEBRASKA. THE MODELS CONTINUE TO HINT AT A NICE AREA OF
DEFORMATION PRECIPITATION DEVELOPING IN THE PANHANDLE THIS
AFTERNOON WITH SOME DECENT ISENTROPIC LIFT NOTED ON THE 310K AND
315K THETA SFC. THIS AREA WILL TRANSITION EAST THIS EVENING WITH
DECENT SUBSIDENCE NOTED BEHIND THIS BAND INTO THE OVERNIGHT. BY
12Z FRIDAY...MOST OF THE CWA WILL BE DRY WITH THE EXCEPTION OF
THE FAR EAST AND SOUTHEAST WHERE A SMALL THREAT FOR PCPN
CONTINUES. AS FOR THE HEAVY RAIN THREAT...ATTM...THINKING IS THAT
THE MAIN THREAT WILL BE EAST OF THE FORECAST AREA UNDERNEATH THE
EXITING COLD POOL THIS MORNING AND THIS AFTERNOON WHERE THE SW
CONUS SUBTROPICAL MOISTURE PLUME IS FOCUSED. WITH THIS IN MIND
AND DUE TO A LACK OF PCPN IN MY EASTERN ZONES PER RADAR ESTIMATES
OVER THE PAST COUPLE OF DAYS...IE...CUSTER...MOST OF
FRONTIER...WHEELER AND GARFIELD COUNTIES...WILL FORGO ANY FLOOD
WATCH FOR TODAY. TWO LOCATIONS THAT MAY NEED TO BE MONITORED FOR
POSSIBLE FLOODING ARE EASTERN FRONTIER COUNTY...AS WELL AS PARTS
OF EASTERN HOLT COUNTY WHERE HEAVIER RAIN FALL TUESDAY NIGHT.
ATTM...THINKING HERE IS THAT SHORT TERM RAINFALL INTENSITIES IN
THESE AREAS WILL NOT BE HIGH ENOUGH TO FACILITATE ANY FLASH
FLOODING. HOWEVER WE MAY NEED SOME SORT OF SMALL STREAM ADVISORY
FOR THESE AREAS AS THEY ARE FULL OF HILLY TERRAIN. WILL CONTINUE
TO MONITOR THESE AREAS INTO THE MORNING HRS.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 355 AM CDT THU AUG 28 2014

BY FRIDAY MORNING THE UPPER LEVEL TROUGH AXIS WILL HAVE PUSHED
INTO CENTRAL KS. MOST OF THE MODELS ARE DRY FOR THE CWA...WITH
ONLY THE NAM STILL SHOWING LINGERING ACTIVITY ACROSS EASTERN
PORTIONS OF N CENTRAL. GENERAL THOUGH IS FRIDAY WILL BE
DRY...HOWEVER WITH THE SLOW MOVEMENT OF THIS SYSTEM...SOME
LINGERING ACTIVITY CAN NOT BE RULED OUT. BY MIDDAY MOSTLY SUNNY
SKIES WILL AID IN WARMING TEMPS INTO THE 80S.

FRIDAY NIGHT INTO SATURDAY A WEAK DISTURBANCE WILL SLIDE ACROSS
THE NORTHERN PLAINS. AT THIS TIME LOOKS LIKE THE BEST DYNAMICS
REMAIN IN THE DAKOTAS AND WILL KEEP CWA DRY. A SFC COLD FRONT
WILL CROSS THE ROCKIES ON SATURDAY WITH SOME COMPRESSIONAL
WARMING AHEAD OF THE FRONT. GUIDANCE DID WARM THINGS UP CLOSE TO
90...HOWEVER RECENT RAINFALL SHOULD DAMPEN THE QUICK RESPONSE OF
TEMPS...EVEN WITH MOSTLY SUNNY SKIES...THUS KEPT HIGHS IN THE
80S. WARMEST TEMPS ARE EXPECTED IN THE WESTERN ZONES.

BY SATURDAY NIGHT AND INTO SUNDAY THE FRONT WILL CROSS THE CWA
WITH A CHANCE FOR THUNDERSTORMS. SFC LOW TRACKS ACROSS THE
DAKOTAS...ALTHOUGH SHOULD HAVE SOME PACIFIC MONSOON MOISTURE TO
TAP. POST FRONTAL RAIN CHANCES CONTINUE WITH THE HIGHER POPS
ASSOCIATED WITH THE UPPER LEVEL TROUGH AXIS ON SUNDAY NIGHT.

SLIGHT NORTHWEST FLOW EARLY IN THE WEEK...THEN FLOW BECOMES MORE
ZONAL AS A BROAD HIGH PRESSURE RIDGE DEVELOPS ACROSS THE SOUTHERN
CONUS. EARLY ON THE DISTURBANCE TRACK IS ACROSS THE HIGH
PLAINS...THEN SHIFTS NORTHWARD. TIMING OF DISTURBANCES DIFFICULT
THIS FAR OUT AND WILL KEEP POPS LOW. HIGHS GENERALLY SEASONAL IN
THE 80S WHILE MILD LOWS ARE IN THE MID 50S TO MID 60S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1153 PM CDT WED AUG 27 2014

THE LINE OF THUNDERSTORMS OVER SOUTHWEST NEBRASKA AND NORTHEAST
COLORADO IS EXPECTED TO MAKE TO OGA-LBF BETWEEN 06Z AND 08Z.
SINCE THE THUNDERSTORM SYSTEM IS WORKING EAST ONLY SLOWLY...WE
WILL USE A LATER TIME FOR ARRIVAL AT LBF. THERE IS CONSIDERABLE
UNCERTAINTY WITH WHETHER OR NOT STORMS WILL AFFECT VTN TONIGHT.
WITH THE PROBABILITY LOW...WE WILL LEAVE THEM OUT OF THE VTN
FORECAST. AFTER THE STORMS PASS...LOW CEILING AND REDUCE
VISIBILITY CAN BE EXPECTED IN STRATUS AND FOG MOST AREAS. FOR THE
SOUTH...THE PROBABILITY OF CEILING BELOW 1000 FEET AGL AND
VISIBILITY BELOW 3SM IS LOW. HOWEVER...IN NORTHERN
NEBRASKA...THERE IS SOME CONSENSUS THAT LOWER VALUES OF CEILING
AN VISIBILITY ARE LIKELY.

LATER IN THE DAY THURSDAY...THERE IS A POSSIBILITY OF
THUNDERSTORMS AGAIN IN THE AFTERNOON AND EVENING...BUT THE
UNCERTAINTY IS HIGH.

&&

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

&&

$$

SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...MASEK
AVIATION...SPRINGER





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