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FXUS64 KLUB 272017
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
317 PM CDT WED MAY 27 2015

.SHORT TERM...
2 PM SURFACE ANALYSIS SHOWS A SURFACE TROUGH-DRYLINE FROM THE
WESTERN TX PANHANDLE SW INTO ERN NEW MEXICO. A DIFFUSE OUTFLOW
BOUNDARY/GRAVITY WAVE IS MOVING WWD ACROSS THE SE TX PANHANDLE AND
ROLLING PLAINS...THERE IS A SLIGHTLY MORE EASTERLY COMPONENT TO THE
WINDS TO THE EAST OF THIS BOUNDARY. A THETA-E RIDGE RUNS NORTH TO
SOUTH FROM THE ERN TX PANHANDLE TO THE CONCHO VALLEY. MLCAPES WITHIN
THIS RIDGE ARE ESTIMATED TO BE IN THE 3000-4000 J/KG RANGE.
HOWEVER...UPPER-AIR ANALYSIS SHOWS WEAK MID-LVL RIDGING OVER WEST
TEXAS...DOWNSTREAM OF ANOTHER SHARP SHORTWAVE TROUGH CENTERED OVER
SRN AZ AND MOVING EASTWARD. DESPITE GUIDANCE INDICATIONS THAT CINH
HAS BEEN ELIMINATED...WEAK SUBSIDENCE WILL LIKELY CONTINUE ACROSS
THE AREA THROUGH EARLY EVENING...AND THIS MAY KEEP T-STORM ACTIVITY
ISOLATED. EVEN SO...ANY STORMS THAT DEVELOP WILL BE IN AN
ENVIRONMENT FAVORABLE FOR RAPID INTENSIFICATION AND SEVERE WEATHER.
AN ISOLATED TORNADO THREAT WILL LIKELY BE CONFINED TO THE FAR SE TX
PANHANDLE. TONIGHT...LARGE-SCALE ASCENT WILL BE ON THE INCREASE AS A
LEAD WAVE FROM THE UPPER TROUGH APPROACHES. THIS WILL SUPPORT
ONGOING T-STORM CHANCES OVERNIGHT...ALTHOUGH THE COVERAGE AND
FAVORED MODE OF CONVECTION REMAINS UNCLEAR AT THIS TIME...WITH WIDE
VARIANCE SHOWN IN MODEL GUIDANCE. THERE MAY VERY WELL BE ONE OR TWO
STORM COMPLEXES MOVING ACROSS WESTERN TEXAS. AND A HEAVY RAIN THREAT
MAY ACCOMPANY THESE COMPLEXES IF THEY DEVELOP. UNFORTUNATELY...THIS
UNCERTAINTY CARRIES ON INTO THE FORECAST FOR THURSDAY...WHICH WILL
BE DEPEND GREATLY ON THE AMOUNT OF ONGOING CONVECTIVE ACTIVITY
THURSDAY MORNING. WITH UPPER-TROUGHING STILL PRESENT AND S-SE LOW
LEVEL FLOW MAINTAINING A RICH MOISTURE INFLUX...WE WOULD EXPECT
DIURNAL HEATING TO BRING ANOTHER SOLID CHANCE OF AFTERNOON AND
EVENING STORMS. HOWEVER...CONVECTIVE DEBRIS AND OUTFLOW ARE LIKELY
TO COMPLICATE THE FORECAST. GUIDANCE TEMPS DO SHOW SLIGHTLY COOLER
TEMPS...MAINLY UPPER 70S AND LOWER 80S...REFLECTING GREATER CLOUD
COVER. FOR NOW WE WILL MAINTAIN A HIGH CHANCE POP MENTION AREA-WIDE.

.LONG TERM...
FORECAST CHANGES IN THE LONG TERM WERE LARGELY COSMETIC AS THE
PATTERN IS STILL ON TRACK TO TRANSITION FROM AN UNSETTLED CYCLONIC
FLOW REGIME TOWARD INCREASINGLY ANTICYCLONIC FLOW BY LATE
SUNDAY THROUGH EARLY NEXT WEEK.

THURSDAY NIGHT THROUGH FRIDAY MORNING WILL FEATURE A DEPARTING S/W
TROUGH IN SW FLOW ALONG WITH A STEADY DECREASE OF POPS FROM W-E.
IGNORING THE RATHER NOISY NAM-WRF AND ITS SUBSEQUENT COLD POOL
MESOHIGHS LATE THURSDAY...REMAINING MODELS ARE CONSISTENT IN
PROGGING GOOD CONVECTIVE CHANCES MAINLY IN OUR EASTERN ZONES
AHEAD OF THE TROUGH...SO LIKELY POPS WERE LEFT INTACT THERE.

FRIDAY AFTERNOON SHOULD SEE A TEMPORARY LULL IN PRECIP CHANCES IN
BETWEEN THE DEPARTED TROUGH AND ANOTHER WAVE UPSTREAM IN COLORADO.
MID-LEVEL WIND FIELDS INDICATE ANTICYCLONIC FLOW DURING THE DAY
WHICH MAY VERY WELL SUPPRESS THE DRYLINE FROM CONVECTING...BUT
SUFFICIENT INSTABILITY AND WEAK CAPPING COULD EASILY TIP THE SCALES
IN FAVOR OF SOME STORMS. BY FAR...A BETTER COVERAGE OF STORMS SEEMS
LIKELY FRI NIGHT AS THE AFOREMENTIONED TROUGH APPROACHES COMPLETE
WITH A CANADIAN FRONT. VEERING OF UPPER WINDS TO A NWLY COMPONENT
SHOULD PROVE FAVORABLE FOR STEERING CONVECTION TOWARD OUR CWA AND
DIRECTLY INTO A THETA-E RIDGE. WITH THE DRYLINE LIKELY BACKING TO
THE NM STATE LINE OR EVEN FARTHER...POPS WERE BOOSTED AREA WIDE ON
THE CAPROCK. POSITION OF THE THETA-E MAX...PWATS AOA 1.5 INCHES AND
SLOW STORM MOTIONS OF 15 KNOTS OR LESS ALL POINT TO A HEAVY RAIN AND
POTENTIAL FLOOD THREAT. INSERTED LOCALLY +RA IN GRIDS FOR THE TIME
BEING.

COLD FRONT IS EXPECTED TO CLEAR THE CWA BEFORE NOON SAT FOLLOWED BY
MUCH LOWER MIXING RATIOS. DID DRY OUT POPS MORE AGGRESSIVELY FROM N-
S THIS DAY AS SURFACE RIDGING APPEARS QUITE STOUT AND UNSUPPORTIVE
OF ADDITIONAL PRECIP. EXCEPTION TO THIS COULD UNFOLD IN THE POST-
FRONTAL UPSLOPE REGIME OF ERN NM WITH STORMS THREATENING OUR WRN
ZONES THROUGH THE EVENING...BUT WITH UPPER RIDGING NOSING INTO THE
REGION AND AN ASSOCIATED WEAKENING OF WINDS ALOFT...THE POTENTIAL
FOR THESE STORMS TO SURVIVE THEIR JOURNEY E-SE INTO OUR LOCALES DOES
NOT APPEAR VERY LIKELY. THEREAFTER...POPS REMAIN DRY AS THE UPPER
RIDGE AXIS AMPLIFIES OVER ALL OF THE SOUTHERN GREAT PLAINS. NUDGED
MAX TEMPS UP TO NEAR OR ABOVE 90 DEG BY TUE-WED AS THICKNESSES SOAR
PARTICULARLY WEST OF THE DRYLINE.

&&

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

$$

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