Area Forecast Discussion
Issued by NWS North Platte, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KLBF 031138
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
638 AM CDT MON AUG 3 2015

.SYNOPSIS...
ISSUED AT 350 AM CDT MON AUG 3 2015

THE H5 PATTERN REMAINS LARGELY UNCHANGED OVER THE PAST
24 HOURS ACROSS CANADA AND THE NRN TIER OF STATES. A CLOSED LOW WAS
PRESENT OVER NRN ONTARIO WITH A TROUGH OF LOW PRESSURE EXTENDING SWD
INTO THE CAROLINAS. RIDGING WAS PRESENT ACROSS THE NRN ROCKIES AND
CANADIAN ROCKIES WHILE A CLOSED LOW WAS PRESENT ACROSS NWRN BRITISH
COLUMBIA. BROAD WEST NORTHWESTERLY FLOW EXTENDED FROM THE CANADIAN
PRAIRIE PROVINCES ESE INTO THE NRN PLAINS AND OHIO VALLEY. ACROSS
THE INTERMOUNTAIN WEST AND THE SOUTH CENTRAL CONUS...HIGH PRESSURE
REMAINED DOMINANT. HOWEVER...A STRONG SHORTWAVE WAS NOTED OVER
EASTERN UTAH THIS MORNING AND SHOWS UP NICELY ON CURRENT WV
IMAGERY. AT THE SURFACE...A COLD FRONT EXTENDED FROM ROUGHLY
OGALLALA TO EUSTIS NEBRASKA. WINDS NORTH OF THIS FEATURE WERE CALM
OR LIGHT FROM THE NORTH...WHILE SOUTH OF THE FEATURE...WINDS WERE
WESTERLY OR SOUTHERLY. SKIES WERE MOSTLY CLOUDY AS ABUNDANT MID AND
HIGH CLOUDS STREAMED INTO SOUTHWESTERN AND WEST CENTRAL NEBRASKA
FROM THE CENTRAL ROCKIES. TEMPERATURES AS OF 3 AM CDT RANGED FROM
62 AT NORTH PLATTE TO 68 AT IMPERIAL.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON AUG 3 2015

THUNDERSTORM CHANCES TODAY AND
TONIGHT WILL BE THE MAIN FORECASTING CHALLENGE. ELEVATED INSTABILITY
WILL CONTINUE TO BE THE DRIVING FORCE FOR CONVECTIVE DEVELOPMENT
THIS MORNING...AS WELL AS LATER TONIGHT. FOR THIS MORNING...A H700
WARM FRONT WILL PUSH FROM CENTRAL NEBRASKA INTO NORTHERN NEBRASKA
THROUGH SUNRISE. THE LATEST NAM...AS WELL AS THE HI RES WARW AND
WNMM SOLUTIONS...AND TO A LESSER DEGREE THE GFS...INITIATE
CONVECTIVE DEVELOPMENT INVOF THIS H7 WARM FRONT THIS MORNING. HAVE
INTRODUCED POPS ACROSS NORTHERN NEBRASKA FOR THIS MORNING...AS WELL
AS THE PRE FIRST PD FCST TO ACCOUNT FOR THIS INSTABILITY AND THE
THREAT FOR STORMS THIS MORNING. ATTM...THIS ACTIVITY IS EXPECTED TO
BE ANCHORED ALONG AND NORTH OF THE FRONT...OR NORTH OF HIGHWAY 92.
THIS ACTIVITY WILL BEGIN TO DISSIPATE BY MIDDAY AS THE H7 FRONT
STALLS ACROSS NORTH CENTRAL NEBRASKA. FURTHER SOUTH...THE SURFACE
FRONT WILL BEGIN TO LIFT SLOWLY NORTH THIS AFTERNOON. BY 21Z...THIS
FEATURE WILL BE ORIENTED FROM AROUND ANTIOCH TO CALLAWAY. ALONG AND
NORTH OF THIS FEATURE...THERE WILL DECENT THREAT FOR THUNDERSTORM
DEVELOPMENT THIS AFTERNOON AS SURFACE HEATING SUFFICIENTLY WEAKENS
THE CAP. ALONG AND NORTH OF THE FRONT...DEEP LAYER SHEAR WILL BE
SUFFICIENT TO SUPPORT SEVERE STORMS. BY EVENING...DEEP LAYER SHEAR
WILL BEGIN TO WEAKEN AFTER MID EVENING. HOWEVER...ELEVATED
INSTABILITY WILL INCREASE ONCE AGAIN OVER NORTHERN PORTIONS IF THE
FORECAST AREA INVOF THE H700 FRONT. THE LATEST NAM SOLN HAS FCST
CAPE OF 500 TO 1000 J/KG CALCULATED FROM THE H700 LAYER ACROSS
NORTHERN NEBRASKA BY LATE EVENING. THIS ALONG WITH VERY STEEP LAPSE
RATES IN THE H500 TO H700 LAYER WOULD SUPPORT STORMS OVERNIGHT...IF
THEY CAN INITIATE AND THIS IS THE WILDCARD IN THE FORECAST. WITH THE
PRESENCE OF THE H85 FRONT AND A 30 KT LOW LEVEL JET TONIGHT...THE
LEADING EDGE OF THIS BEING FOCUSED ACROSS THE SANDHILLS AND NORTHERN
NEBRASKA...MAY PROVIDE ENOUGH LIFT PUSH ANY LOWER LEVEL CONVECTION
UP TO THE VERY UNSTABLE MID LEVELS TONIGHT. IF THIS CAN BE
ACHIEVED...WE COULD SEE PERSISTENT STORMS OVERNIGHT IN THE NORTH.
THERE IS GOOD SUPPORT FOR THIS PLAYING OUT WITH THE LATEST
NAM...WARW AND WNMM SOLNS FOR TONIGHT...SO FEEL CONFIDENT ENOUGH TO
RAISE POPS ACROSS THE NORTH OVERNIGHT. AS FOR TEMPERATURES
TODAY...SOUTH OF THE FRONT...READINGS WILL REACH THE LOWER TO MIDDLE
90S. ACROSS NORTHERN PORTIONS OF THE FORECAST AREA...TEMPS WILL
STRUGGLE TO TOP THE LOWER TO MIDDLE 80S THANKS TO CLOUD COVER AND
COOLER H85 TEMPS NORTH OF THE FRONT. FOR TONIGHT...LOWS WILL BE IN
THE 60S THANKS TO INCREASING LOW LEVEL MOISTURE OVERNIGHT...AS WELL
AS EXPECTED CLOUD COVER.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON AUG 3 2015

A POTENT SHORTWAVE ALOFT CURRENTLY IN UTAH...WILL LIFT NORTH INTO
WYOMING TONIGHT AND THEN TURN EAST AND CROSS THE AREA TUESDAY AND
TUESDAY NIGHT. ALTHOUGH THE MODELS VARY SOMEWHAT WITH THE STRENGTH
AND EXACT LOCATION OF THE WAVE AS IT CROSSES THE AREA...THEY ALL
INDICATE AN UPTICK IN TSTM ACTIVITY. A SURFACE FRONT WILL BE NEARLY
STATIONARY FROM NORTHWEST TO SOUTHEAST ACROSS THE IMMEDIATE AREA
TUESDAY INTO TUESDAY NIGHT...AND EXPECT THAT THIS WILL HELP FOCUS
TSTM DEVELOPMENT. SCATTERED TSTMS SHOULD ACTUALLY ALREADY BE ONGOING
EARLY TUESDAY MORNING ACROSS MUCH OF THE AREA IN ZONE OF BROAD
ISENTROPIC LIFT. TSTMS...AT LEAST IN A SCATTERED FASHION...MAY
CONTINUE THROUGH MOST OF THE DAY...AND EXPECT QUITE A BIT IN THE WAY
OF MID AND HIGH LEVEL CLOUDINESS AS A RESULT. THIS COULD CUT DOWN
SOME ON THE SEVERE THREAT AS SURFACE BASED INSTABILITY MAY BE
SOMEWHAT MEAGER. ANOTHER LIMITING FACTOR FOR ORGANIZED SEVERE STORMS
WILL BE RATHER WEAK WINDS ALOFT. THE BIGGER THREAT WILL LIKELY BE
LOCALLY HEAVY RAIN IN SOME PLACES. HAVE MAINTAINED THE 40 TO 50 POPS
FOR THE TUESDAY/TUESDAY NIGHT TIMEFRAME AS THE WAVE CROSSES THE
AREA.

WEDNESDAY INTO THE WEEKEND...THE SURFACE FRONT WILL LINGER IN THE
AREA...WITH SEVERAL WEAK UPPER LEVEL DISTURBANCES CROSSING THE AREA
WITHIN WESTERLY FLOW ALOFT. ECMWF INDICATES A STRONGER WAVE MAY
CROSS THE AREA SATURDAY AND SATURDAY NIGHT...AND WILL CARRY SOMEWHAT
HIGHER CHANCES FOR TSTMS DURING THAT PERIOD. TEMPERATURE WISE...WITH
THE UPPER LEVEL RIDGE REMAINING ACROSS THE SOUTHERN PLAINS...EXPECT
THE HOT TEMPERATURES TO REMAIN IN THAT AREA UNDER THE RIDGE. IN OUR
REGION TEMPERATURES WILL AVERAGE NEAR NORMAL...IN THE MID TO UPPER
80S. NO HEAT WAVES SEEN IN THE IMMEDIATE FUTURE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM CDT MON AUG 3 2015

FOR THE KLBF TERMINAL...OVER THE NEXT 24 HOURS...ABUNDANT HIGH
CLOUDINESS WILL STREAM INTO SOUTHWESTERN NEBRASKA FROM THE CENTRAL
ROCKIES. EXPECT BROKEN TO OVERCAST SKIES RANGING FROM 15000 TO
20000 FT AGL. SOME BROKEN CIGS AROUND 8000 FT AGL ARE EXPECTED
TONIGHT. THERE IS A THREAT FOR THUNDERSTORMS LATE THIS AFTERNOON
AND EVENING...HOWEVER THE THREAT IS TOO SMALL TO MENTION IN THE
12Z KLBF TAF. FOR THE KVTN TERMINAL...EXPECT SCATTERED CIGS AROUND
20000 FT AGL THIS MORNING AND THIS AFTERNOON. CLOUDS WILL INCREASE
AFTER 00Z TUESDAY...WITH A DECENT THREAT FOR THUNDERSTORMS FROM
03Z TO 09Z TUESDAY. CIGS IN ANY THUNDERSTORMS SHOULD BE AROUND
5000 FT AGL WITH VISBYS AS LOW AS 4SM.

&&

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

$$

SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...TAYLOR
AVIATION...CLB



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.