Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 102023
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
323 PM CDT THU JUL 10 2014

.SYNOPSIS...
ISSUED AT 323 PM CDT THU JUL 10 2014

AT H5 STRING OF CLOSED LOWS FROM THE GULF OF ALASKA INTO CENTRAL
CANADA AND NORTHEAST CANADA. HIGH OVER SOUTHERN CONUS WITH MAINLY
ZONAL FLOW FROM THE WEST COAST INTO THE GREAT LAKES. AT THE
SURFACE WARM FRONT MOVING EAST INTO THE NEBRASKA PANHANDLE SOUTH TO
AN AREA OF LOW PRESSURE OVER SOUTHEAST COLORADO WITH STATIONARY
BOUNDARY FROM THE OKLAHOMA PANHANDLE TO DC.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM CDT THU JUL 10 2014

CONVECTION CHANCES HIGHLIGHT THE SHORT TERM
DISCUSSION.  LATE THIS AFTERNOON AND EVENING...UPPER RIDGE ATOP THE
CENTRAL AND NORTHERN PLAINS WILL CONTINUE TO BREAK DOWN
/FLATTENED/ BY A DEEP UPPER TROUGH ADVANCING EAST ACROSS THE
CANADIAN PRAIRIES.  WITH QUASI-ZONAL FLOW IN PLACE...WEAK
DISTURBANCE PASSING THROUGH THE FLOW WILL AID IN FOCUSING
THUNDERSTORM DEVELOPMENT ALONG AN INVERTED SURFACE TROUGH SHOWN TO
BISECT THE NEBRASKA PANHANDLE NORTH INTO CENTRAL NEBRASKA THIS
EVENING.  WITH AMPLE INSTABILITY IN PLACE AND 0-6KM SHEAR AS HIGH AS
45 KTS...SEVERE STORMS ARE POSSIBLE.  LARGE HAIL AND GUSTY WIND WILL
ONCE AGAIN BE EXPECTED.  LATEST MESOANALYSIS ACROSS CENTRAL AND
WESTERN NEBRASKA INDICATE CAPE VALUES IN EXCESS OF 2000 J/KG WITH
THE AFOREMENTIONED SHEAR ALREADY IN PLACE...BUT MODERATE CAPPING
REMAINS...STORM INITIATION SHOULD HOLD OFF UNTIL LATE
AFTERNOON/EARLY EVENING.  INTO THE OVERNIGHT...A LOW LEVEL JET IS
SHOWN TO INTENSIFY AND HELP FOCUS FURTHER DEVELOPMENT INTO
CONVECTIVE CLUSTERS.  THE LATEST CONVECTIVE ALLOWING MODELS HAVE
TRENDED A BIT FURTHER SOUTH WITH PROJECTIVE ADDITIONAL DEVELOPMENT
REACHING AS FAR SOUTH AS THE INTERSTATE 80 CORRIDOR.  SUFFICIENT
ELEVATED CAPE WILL KEEP THE THREAT OF SEVERE HAIL GOING INTO THE
EARLY DAWN HOURS.  ATTM...THE GREATEST CHANCES OF OVERNIGHT ELEVATED
STORMS WILL REMAIN ACROSS THE NORTH...BUT AT THAT...CHANCES WILL
REMAIN LESS THAN 40 PERCENT AS SUFFICIENT MODEL SUPPORT/TIMING IS
SOMEWHAT LACKING.

FRIDAY...A FRONTAL BOUNDARY WILL STRETCH NORTHEAST ACROSS
SOUTHERN/CENTRAL NEBRASKA WITHIN A FAVORABLE MOIST AND UNSTABLE
ENVIRONMENT.  AS DIABATIC HEATING FULLY COMMENCES STORMS SHOULD
BEGIN TO DEVELOP AND POTENTIALLY BECOME SEVERE...AIDED BY EFFECTIVE
BULK SHEAR OF GREATER THAN 30 KTS. LARGE HAIL AND DAMAGING WIND WILL
ONCE AGAIN BE EXPECTED. HIGHEST POP CHANCES WILL BE ACROSS THE WEST
DURING THE AFTERNOON...WITH THE GREATER COVERAGE OCCURRING BEYOND
00Z SATURDAY WITH THE INTENSIFICATION OF THE LLJ.  AS IS THE CASE
FOR THIS EVENING...MODEL CONSISTENCY AND AGREEMENT IS SOMEWHAT
LACKING...THUS YIELDING LOWER CONFIDENCE IN THE SHORT TERM
CONVECTIVE FORECAST.

FOR TEMPERATURES...WILL CONTINUE TO EMPLOY A GENERAL BLEND OF
NUMERICAL GUIDANCE WITH THE PREVIOUS FORECAST...THIS BLEND SUGGESTS
HIGHS IN THE MID 80S TO LOWER 90S NORTH TO SOUTH ACROSS THE
CWA...WITH OVERNIGHT LOWS TONIGHT MAINLY IN THE MID 60S.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM CDT THU JUL 10 2014

MID AND LONG TERM MODELS HAVING SOME DIFFERENCES WITH PLACEMENTS
OF SURFACE BOUNDARIES AND TIMING OF WAVES THROUGH FAST ZONAL FLOW.
WILL USE A BLEND FOR THE FORECAST IN MID TERM. MAIN FORECAST
CHALLENGE PRECIPITATION THIS WEEKEND INTO THE FIRST PART OF THE
WEEK AND THEN COOL DOWN. SURFACE LOW AND BOUNDARY OVER NORTHWEST
KANSAS FRIDAY EVENING WITH COOL FRONT OVER SOUTH DAKOTA. BOUNDARY
TO LIFT NORTH THROUGH THE EVENING WITH THUNDERSTORM DEVELOPMENT
ALONG THE BOUNDARY AS THE LOW LEVEL JET KICKS IN. BUFR SOUNDINGS
HAVE UNSTABLE BOUNDARY LAYER AND MUCAPES APPROACHING 250O J/KG.
BULK SHEAR AROUND 30 TO 40KTS WILL AID IN THE DEVELOPMENT OF SUPER
CELLS ALONG THE QUASI STATIONARY BOUNDARY WHICH WILL LIE SOME
WHERE ACROSS THE CWA. SLOW STORM MOVEMENT AND PW`S AROUND AN INCH
COULD BRING SOME MODERATE RAINFALL AMOUNTS. SOME LINGERING TSRA
SATURDAY MORNING ALONG THE BOUNDARY. WITH HEATING OF THE DAY AND
WAVE MOVING THROUGH SATURDAY EVENING STORMS REGENERATE ALONG THE
BOUNDARY OVER SOUTHERN NEBRASKA. BOUNDARY MOVES SOUTH INTO KANSAS
AS HUDSON BAY LOW RETROGRADES AND MOVES SOUTH INTO THE NORTHERN
PLAINS. FEW LINGERING SHOWERS SUNDAY AND SUNDAY NIGHT AS UPPER LOW
OVER CENTRAL CANADA PUSHES WAVES THROUGH IN FAST NORTHWEST FLOW.
MUCH COOLER TEMPERATURES MOVING AS STRONG UPPER LOW DROPS ACROSS
MINNESOTA WITH TEMPERATURES LOWERING INTO THE 70S ACROSS THE CWA.
TEMPERATURES MAY HAVE TO BE LOWERED. TEMPERATURES SLOWLY RISING
INTO THE 80S BY BY THURSDAY AND DRY AS THE UPPER LOW PUSHES A COLD
FRONT ACROSS THE SOUTHERN PLAINS INTO THE GULF WITH COOLER DRIER
AIR MOVING INTO THE NORTHERN PLAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1259 PM CDT THU JUL 10 2014

THUNDERSTORMS TO POSSIBLY IMPACT REGIONAL TERMINALS THIS
EVENING...OVERNIGHT AND AGAIN LATE IN THE TAF PERIOD TOMORROW.
ATTM...THE GREATEST THREAT OF STORMS THIS EVENING WILL BE ACROSS
THE SANDHILLS AND POINTS NORTH...WITH THE LATEST GUIDANCE FROM THE
CONVECTION ALLOWING MODELS INDICATING STORMS AT KVTN AFTER
03Z. AT KLBF...STORMS CHANCES ARE CONDITIONAL...BUT THE MOST
LIKELY INITIATION TIME WOULD BE AFTER 06Z. CONFIDENCE IN
THUNDERSTORMS AT LBF IS LOW...BUT SLIGHTLY HIGHER AT KVTN. IF
STORMS ARE REALIZED...LARGE HAIL AND GUSTY ERRATIC WIND WOULD BE
ANTICIPATED. FOR THE OVERNIGHT AND TOMORROW...ELEVATED INSTABILITY
AND A STRENGTHENING LOW LEVEL JET WILL CONTINUE STORMS CHANCES
THROUGH THE FORECAST PERIOD FOR MUCH OF THE REGION.


&&

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

$$

SYNOPSIS...POWER
SHORT TERM...JACOBS
LONG TERM...POWER
AVIATION...JACOBS





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