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000
FXUS64 KLUB 281908
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
208 PM CDT THU APR 28 2016

.AVIATION...
THUNDERSTORMS ARE EXPECTED TO DEVELOP BY 20Z-21Z INVOF KLBB/KPVW
AND MOVE NE. ADDITIONAL DEVELOPMENT TOWARD KCDS WILL BE POSSIBLE.
CONVECTIVE ACTIVITY IS EXPECTED TO RAPIDLY BECOME SEVERE AND WIDE
BERTH SHOULD BE GIVEN AS STRONG DOWNBURST POTENTIAL IS POSSIBLE.
OUTSIDE OF CONVECTION...VFR IS EXPECTED TO PREVAIL. ANOTHER ROUND
OF THUNDERSTORM ACTIVITY IS EXPECTED OVERNIGHT AND EVOLUTION OF
THIS SYSTEM WILL BE CONTINGENT ON HOW THINGS EVOLVE DURING THE
AFTERNOON THOUGH THE GENERAL EXPECTATION IS THAT COVERAGE WILL BE
MORE WIDESPREAD.

&&

.UPDATE...
MOISTURE RETURN HAS BEEN FAIRLY ROBUST WITH THETA-E AXIS
EXTENDING JUST WEST OF THE US-87 I-27 CORRIDOR THENCE CURVING BACK
A BIT NORTHWEST TOWARD DIMMITT. CUMULUS HAS DEVELOPED ALONG THE
WESTERN EDGE OF THE AXIS AND THIS IS AN AREA WHICH IS HINTED AT
FOR INITIATION BY MANY OF THE HIGHER RESOLUTION NWP SOLUTIONS.
OVER THE PAST SEVERAL HOURS...THE THETA-E RIDGE HAS BECOME A BIT
MORE N/S ORIENTED AND WHILE THE ORIENTATION OF THE MID LEVEL FLOW
IS NOT NEARLY AS NORMAL TO THE SURFACE BOUNDARY...IT SHOULD REMAIN
FAVORABLE FOR DISCRETE CONVECTION. WINDS CONTINUE TO BACK
ESPECIALLY ACROSS THE NORTHEASTERN SOUTH PLAINS AND NORTHERN
ROLLING PLAINS GIVEN PRESSURE FALLS TO OUR WEST IN RESPONSE TO
APPROACHING UPPER LEVEL LOW. THIS WILL HELP TO INCREASE LOW LEVEL
HELICITY AND ENHANCE RISK OF LOW LEVEL ROTATION. 0-1KM SHEAR IS
NOT TERRIBLY IMPRESSIVE THIS AFTERNOON BUT DOES RAMP UP SHARPLY
FOR THE SECOND ROUND OF SEVERE CONVECTION TONIGHT. HAVE INCREASED
POPS FOR THIS AFTERNOON ACROSS THE EASTERN PART OF THE CWFA ALONG
WITH ATTENDANT MENTION OF SEVERE. THREAT OF
BASEBALLS/70MPH/TORNADOES CONTINUES TO LOOK REASONABLE. OVERALL A
GUARDED VIGILANCE OF WEATHER CONDITIONS REMAINS WARRANTED THIS
AFTERNOON AND OVERNIGHT.


&&

.PREV DISCUSSION... /ISSUED 616 AM CDT THU APR 28 2016/

AVIATION...
GUSTY SOUTHEAST TO SOUTH WINDS TO DEVELOP BY LATE MORNING AND
PERSIST THROUGH THE EVENING. POTENTIAL FOR TS AT KCDS AROUND 00Z
WITH EXPECTATION OF ISO TO SCT STORMS INITIATING SW OF KCDS AND
EAST OF KLBB AND KPVW. FAIRLY LOW CONFIDENCE IF STORMS WILL AFFECT
KCDS ATTM SO WILL KEEP MENTION OUT FOR NOW. BETTER CHANCES FOR
KPVW AND KCDS AFTER 06Z WILL SUPPORT A TEMPO MENTION IN BOTH THOSE
TAFS.

PREV DISCUSSION... /ISSUED 402 AM CDT THU APR 28 2016/

SHORT TERM...
LOW-AMPLITUDE SHORT WAVE RIDGING OVERHEAD BETWEEN AN UPPER LOW OVER
THE CENTRAL PLAINS AND ANOTHER UPPER LOW OVER THE GREAT BASIN TO SRN
CALIFORNIA. THIS RIDGING WILL GIVE WAY PRETTY QUICKLY THIS MORNING
AS THE WESTERN CONUS UPPER LOW MOVES TO THE 4-CORNERS BY THE END OF
THE DAY. AT THE SFC WILL SEE THE DRYLINE SHIFT EWD TO OR JUST EAST
OF THE I-27 CORRIDOR BY ABOUT 21Z. SFC DEW POINTS IN THE LOWER 50S
POISED JUST TO THE EAST AND SOUTHEAST OF THE FCST AREA...BUT RICHER
MOISTURE IS WELL TO THE SOUTHEAST OF THE REGION TO THE SOUTH AND
EAST OF SAN ANTONIO. SOME OF THAT IS PROGGED TO REACH THE ROLLING
PLAINS THIS AFTERNOON TO OFFSET SOME MIXING FROM DIURNAL HEATING.
00Z WRF-NAM THE MOST EXTREME WITH LOW LEVEL MOISTURE EAST OF THE
DRYLINE AND THUS WITH CAPE VALUES /EXCEEDING 2500 J/KG AT 00Z/ WHILE
OTHER MODELS ARE MORE MEASURED AND ON THE ORDER OF 1500 J/KG AT THAT
SAME TIME. ATTM TEND TO PREFER THE LATTER VALUES WHICH STILL
CERTAINLY LEADS TO THE POSSIBILITY OF DISCRETE SUPERCELLS IN THE
ROUND OF CONVECTION THAT IS PROGGED TO INITIATE NEAR THE DRYLINE
AROUND 21Z. FORCING AT THAT TIME OF THE DAY WILL BE RELATIVELY WEAK
SO 20-30 PCT POPS SHOULD HANDLE PERIOD OF INITIATION...SLIGHTLY
HIGHER MOVING INTO EARLY EVENING AS THE CONVECTION MATURES. ALSO
EARLY EVENING WILL SEE THE DRYLINE PUSH QUICKLY WWD WITH LOW LEVEL
MOISTURE POISED TO BE WORKED ON BY GOOD MID TO UPPER LEVEL LIFT IN
ADVANCE OF THE 4-CORNERS UPPER LOW THAT WILL STILL BE HEADED EWD
ACROSS NORTHERN NEW MEXICO. THIS WILL PROMOTE A SECOND ROUND OF
THUNDERSTORMS...LIKELY INITIATING WEST OF I-27 AFTER 06Z. FOCUS
OF LIFT WILL FAVOR THE NORTHERN HALF OF THE FCST AREA...BUT SHOULD
ALSO SEE SOME ATTEMPTS TO BUILD SWD INTO LOW LEVEL JET. THIS
SECOND ROUND ALSO HAS THE POTENTIAL TO BE SEVERE WITH HEALTHY
AMOUNTS OF ELEVATED CAPE PROGGED THROUGH THE NIGHT.

LONG TERM...
WHAT LINGERING STORMS REMAIN BY 12Z FRIDAY SHOULD MAKE AMPLE
STRIDES NEWD AND OUT OF THE CWA BY LATE MORNING AHEAD OF A MID-
LEVEL JET STREAK AND PRONOUNCED DRYING/SUBSIDENCE. AS THE UPPER
LOW PIVOTS NORTHWARD ACROSS COLORADO...THE AXIS OF A 70+ KNOT 500
MB JET CORE WILL OVERSPREAD THE REGION AND SERVE TO ACCELERATE
THE DRYLINE EASTWARD. CLOUD DEBRIS FROM A.M. PRECIP SHOULD EASILY
BE SCOURED OUT UNDER DRY SLOTTING AND ALLOW FOR SOME AFTERNOON
DESTABILIZATION ALONG THE DRYLINE WHICH LOOKS TO RESIDE IN OUR
NERN COUNTIES BY MIDDAY. THE WINDOW FOR ADDITIONAL STORMS DOES
LOOK RATHER SMALL IN THIS AREA PARTICULARLY WITH THE DRYLINE
SPEEDING NORTHEAST THROUGH THE AFTERNOON...BUT THIS WINDOW IS
STILL ENOUGH TO WARRANT LOW POPS BEFORE THE DRYLINE DEPARTS FOR
GOOD BEFORE 00Z. ATTM...THE SEVERE STORM THREAT IN THE SERN
PANHANDLE AND NRN ROLLING PLAINS IS PRETTY NARROW IN TIME AND
SPACE GIVEN UTTERLY BONKERS BUNKERS STORM MOTIONS OF 50 KNOTS AND
A SPEEDY DRYLINE. THIS MOTION WOULD DISPLACE MOST STORM EMBRYOS
OUT OF OUR CWA IN RAPID FASHION BEFORE CELLS CAN FULLY MATURE
FARTHER DOWNSTREAM. ON A RELATED NOTE...MOS AND SUPERBLEND WIND
SPEEDS LOOK TOO CONSERVATIVE FOR THIS POST-DRYLINE PATTERN UNDER A
STRONG JET MAXIMUM...SO HAVE NUDGED THESE VALUES UP INTO THE 25-30
MPH TERRITORY FOR MOST OF THE SOUTH PLAINS.

ASIDE FROM SOME RESIDUAL COLD POCKET AND DIURNALLY-DRIVEN SHOWERS
IN NERN NM AND THE WRN PANHANDLE...A LARGELY DRY COLD FRONT WILL
ARRIVE FRI NIGHT FROM THE NW ALL THE WHILE THE UPPER LOW BECOMES
STACKED AND NEARLY STATIONARY NEAR GOODLAND KANSAS. THIS FRONT
SHOULD SLOW ON SATURDAY BEFORE STALLING WELL TO OUR S-W ALL IN
ADVANCE OF ANOTHER UPPER LOW DIGGING INTO THE DESERT SW BY SUNDAY.
THIS BROAD POST-FRONTAL UPSLOPE PATTERN UNDER SLOW RE-MOISTENING
ALOFT IN SW FLOW TENDS TO FAVOR PRECIP MOSTLY IN NM THIS WEEKEND...
BUT WE HAVE RETAINED SOME LOW CHANCE MENTION IN OUR NWRN COUNTIES
FOR ANY ERRANT HIGH PLAINS DRIFTERS. MOIST ISENTROPIC LIFT IS
PROGGED TO PEAK SUN NIGHT AND EARLY MONDAY AS THE NEW UPPER LOW
MIGRATES EAST...ALTHOUGH THE CHARACTER OF THIS LOW IS ONE OF A
WEAKENING THEME BY THIS POINT WHICH RAISES SOME CONCERN OVER THE
QUALITY OF SATURATED DEPTHS AND PWAT VALUES. AT THE VERY LEAST...
ANOTHER COLD FRONT BY SAT NIGHT AND INCREASING CLOUD COVER
THEREAFTER COULD MAKE FOR AN UNSEASONABLY COOL START TO MAY
WITH MONDAY SHOWING THE MOST PROMISE PROVIDED SHOWERS PAN OUT AS
ADVERTISED. A PERIOD OF MOSTLY DRY NW FLOW THEN UNFOLDS THROUGH
MID-WEEK AHEAD OF A LONG WAVE RIDGE SPANNING THE FULL EXTENT OF
THE CANADIAN AND U.S. ROCKIES. PATTERN WISE...THESE HIGH AMPLITUDE
RIDGES TEND TO BE A BIT MORE RESILIENT THAN MODELS INDICATE WHICH
COULD PROLONG TUESDAY/S DRYING ALL THE WAY INTO FRIDAY BEFORE A
REGIONAL SEVERE WX PATTERN LOOKS TO UNFOLD.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

26/99/26


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