Area Forecast Discussion
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FXUS64 KLUB 241752
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1252 PM CDT SUN MAY 24 2015

.AVIATION...
18Z TAFS...STUBBORN MVFR CEILINGS HANGING ON AT KCDS AND ACROSS
THE EASTERN TEXAS PANHANDLE. EXPECT WITH ANOTHER HOUR OR SO OF
HEATING BASES SHOULD RISE TO VFR. ISOLATED THUNDERSTORMS ARE
POSSIBLE THIS AFTERNOON...THOUGH CONFIDENCE IS NOT HIGH ENOUGH TO
INCLUDE IN ANY TERMINAL FORECASTS AT THIS TIME GIVEN THE EXPECTED
NATURE OF COVERAGE. SOUTHERLY WINDS ARE EXPECTED AT AROUND 8 TO
15KTS. LOW CONFIDENCE ON A RETURN TO MVFR OR POSSIBLY IFR
CONDITIONS TO KCDS AND THE EASTERN TEXAS PANHANDLE EARLY MONDAY
MORNING.

&&

.PREV DISCUSSION... /ISSUED 1154 AM CDT SUN MAY 24 2015/

UPDATE...
PRIMARY CONCERN THIS AFTERNOON IS ON CONVECTIVE POTENTIAL...INCLUDING
THE POSSIBILITY OF SEVERE WEATHER SHOULD STORMS DEVELOP. MORNING WATER
VAPOR IMAGERY SHOWS A DEPARTING SHORTWAVE TROUGH WITH WEAK HEIGHT RISES
PROGGED THROUGH THE AFTERNOON AND EARLY EVENING HOURS. AT THE SURFACE...WINDS
WERE VEERED ACROSS THE CENTRAL AND WESTERN ZONES WITH DRIER AIR NOTED
ADVECTING IN. FURTHER EAST...WINDS WERE BACKED OFF THE CAPROCK WITH
DEWPOINTS HOLDING IN THE LOWER TO MIDDLE 60S. THIS PATTERN WILL SUPPORT
A TIGHTENING DRYLINE THROUGH THE AFTERNOON HOURS LIKELY SETTING UP SOMEWHERE
NEAR THE EASTERN EDGE OF THE CAPROCK. A COUPLE HIGH-RES SOLUTIONS EVEN
SUGGEST THE DRYLINE COULD BE AS FAR WEST AS A DIMMITT TO PLAINVIEW TO
POST LINE BY 21Z. REGARDLESS OF EXACTLY WHERE THE DRYLINE IS LOCATED...FORCING
ALONG IT COULD BE ENOUGH TO SUPPORT ISOLATED TO WIDELY SCATTERED CONVECTIVE
DEVELOPMENT BY MID TO LATE AFTERNOON. CONVECTIVE INITIATION IS A
BIT UNCERTAIN THOUGH WITH LARGE SCALE SUPPORT LACKING AND EVEN SOMEWHAT
UNFAVORABLE. HOWEVER...SHOULD STORMS FORM...MODERATE INSTABILITY AND
DEEP LAYER WIND SHEAR WILL SUPPORT A SEVERE THREAT. THE PRIMARY RISK
WOULD BE HAIL TO GOLF BALL SIZE AND WIND GUSTS TO 60 MPH. ADDITIONALLY...0
TO 3 KM HELICITY VALUES INCREASING IN EXCESS OF 200 M2/S2 ALONG WITH
RELATIVELY LOW LCLS AND BACKED FLOW COULD EVEN SUPPORT AN ISOLATED TORNADO
THREAT IN THE ROLLING PLAINS DURING THE EARLY EVENING HOURS. ANY CONVECTION
WILL LIKELY QUICKLY FADE AFTER SUNSET WITH THE LACK OF ANY LARGE SCALE
SUPPORT...THOUGH ADDITIONAL ACTIVITY COULD THREATEN THE SOUTHEAST ZONES
AS EARLY AS TOMORROW MORNING AS A ROBUST SHORTWAVE TROUGH APPROACHES
THAT REGION FROM THE WEST-SOUTHWEST.

PREV DISCUSSION... /ISSUED 731 AM CDT SUN MAY 24 2015/

AVIATION...
LOCALLY DENSE FOG CURRENTLY IMPACTING KCDS WITH MOIST SOUTHEASTERLY
WINDS IN PLACE. SHOULD BEGIN TO SEE THIS MIX OUT IN THE NEXT HOUR
OR TWO...RESTORING AIRPORT OPERATIONS BY 13-14Z. MVFR/IFR CONDITIONS
WILL LIKELY PERSIST AFTER THIS UNTIL AROUND MID-LATE MORNING WHEN
VEERING SOUTHERLY WINDS SHOULD RESTORE VFR CONDITIONS. KLBB AND
KPVW WILL CONTINUE TO SEE IFR CEILINGS FOR A SHORT PERIOD THIS
MORNING BEFORE INCREASING SOUTH/SOUTHWESTERLY WINDS LIFT THESE TO
MVFR AND VFR BY MID MORNING. CHANCE OF THUNDERSTORMS EXISTS AT
KCDS THIS AFTERNOON/EARLY EVENING...BUT COVERAGE EXPECTED TO BE
LOW ENOUGH THAT IMPACT AT TERMINAL REMAINS TOO UNLIKELY FOR
MENTION AT THIS TIME. SOME LOWER CLOUDS/POTENTIAL CEILINGS MAY
TRY TO MOVE BACK TOWARD KCDS OVERNIGHT...BUT DRIER AIR FILTERING
IN FROM THE WEST LOOKS TO KEEP THIS POSSIBILITY LOW FOR THE TIME
BEING.

PREV DISCUSSION... /ISSUED 423 AM CDT SUN MAY 24 2015/

SHORT TERM...
MID-LEVEL IMPULSE PROPAGATING THROUGH THE BIG BEND INTO THE EDWARDS
PLATEAU CONTINUES TO DRIVE A PLETHORA OF CONVECTION ACROSS CENTRAL
INTO NORTHERN TEXAS...WITH A WELL DEFINED MESOSCALE CONVECTIVE
VORTEX IN BETWEEN THE METROPLEX AND SHERMAN. HAVE SEEN SOME TRAILING
SHOWERS/STORMS GET GOING BETWEEN PECOS AND BIG SPRING WHICH COULD
ATTEMPT TO MOVE INTO THE ROLLING PLAINS LATER THIS MORNING...BUT
EXPECTING THESE TO HAVE A TOUGH TIME BLOSSOMING IN THE WAKE OF THE
MUCH STRONGER SHIELD OF ACTIVITY EAST. PLENTY OF MOISTURE WILL
REMAIN IN PLACE EAST OF THE CAPROCK ESCARPMENT AS THE RIGHT ENTRANCE
REGION OF AN UPPER JET REMAINS IN CLOSE PROXIMITY ON THE DOWNSTREAM
SIDE OF THE PARENT UPPER LOW MEANDERING ACROSS THE INTERMOUNTAIN
WEST.

WEAK SUBSIDENCE THIS AFTERNOON...BEHIND THE AFOREMENTIONED
DISTURBANCE AS IT PUSHES INTO CENTRAL OKLAHOMA/KANSAS...WILL LIKELY
KEEP MOST AREAS DRY AS A SURFACE LOW ALSO NUDGES EASTWARD FROM THE
FRONT RANGE TOWARD THE HIGH PLAINS THUS MIXING THE DRYLINE NEAR OR
EAST OF THE CAPROCK ESCARPMENT. WET SOILS AND FALLING PRESSURES IN
EASTERN NEW MEXICO MAY ATTEMPT TO KEEP THIS FEATURE ACROSS THE
EASTERN SOUTH PLAINS FOR A TIME THIS AFTERNOON...BUT SYNOPTIC
FORCING SHOULD ULTIMATELY WIN OUT BY MID AFTERNOON AND PEAK HEATING.
BEST CHANCES FOR ANY AFTERNOON/EVENING CONVECTIVE DEVELOPMENT WILL
BE ALONG THE DRYLINE WHERE SURFACE CONVERGENCE IS MAXIMIZED. LOCALES
IN THE FAR SOUTHEASTERN PANHANDLE/NORTHERN ROLLING PLAINS MAY BE
HELPED BY ANY MINOR SHORTWAVE PERTURBATIONS NEARER THE CORE OF THE
UPPER LOW...BUT WIDESPREAD HEIGHT RISES LOOK TO BE THE OVERALL RULE
FOR WEST TEXAS. NONETHELESS...ANY STORM THAT CAN DEVELOP WILL HAVE
PLENTY OF INSTABILITY AND NO CAP TO FIGHT AGAINST AS STEEP LAPSE
RATES WILL DEVELOP OWING TO QUITE COOL MID-LEVEL TEMPERATURES AND
SURFACE TEMPERATURES CLIMBING INTO THE UPPER 70S-MID 80S.
THEREFORE...LARGE HAIL WILL CERTAINLY BE A THREAT GIVEN 30-40 KNOTS
OF DEEP LAYER SHEAR IS SUFFICE FOR UPDRAFT ORGANIZATION.

A QUIET OVERNIGHT PERIOD SHOULD THEN ENSUE AS VEERING SURFACE WINDS
LIKELY KEEP LOW STRATUS/FOG EAST OF THE ROLLING PLAINS AND FAR
SOUTHEASTERN PANHANDLE. ANOTHER UPPER DISTURBANCE WILL APPROACH THE
TRANS-PECOS...BUT ANY IMPACT IN TERMS OF THUNDERSTORM DEVELOPMENT
WOULD BE DELAYED UNTIL AFTER DAYBREAK MEMORIAL DAY PENDING MOISTURE
RETURN.

LONG TERM...
SHORTWAVE TROUGH WILL BE JUST WEST OF THE AREA BY 12Z MONDAY
LEAVING US ON THE SUBSIDENT SIDE OF THE FEATURE BY THE TIME THE
AFTERNOON ROLLS AROUND. AFTER PASSAGE...THOUGH NEAR ZONAL IS
EXPECTED TO PERSIST INTO MONDAY...EMBEDDED DISTURBANCES ARE
EXPECTED THUS KEEPING THINGS FROM MAKING THE FCST TOO SIMPLE. INTO
THURSDAY...TROUGHING RETURNS TO THE DESERT SOUTHWEST WITH A RETURN
OF SWRLY FLOW ALOFT WHICH CONTINUES TO BE A HARBINGER OF ACTIVE
WEATHER THURSDAY AND FRIDAY. THE SYNOPTIC PATTERN REMAINS A BIT
MUDDIED UNTIL RIDGING OUT WEST FINALLY LOOKS TO START INTO THE
PICTURE NEXT WEEKEND. AS AN ASIDE...BOTH THE GFS AND ECMWF SPIN UP
A TROPICAL SYSTEM IN THE PACIFIC AROUND 1 JUNE.

DETERMINISTIC GUIDANCE PAINTS A DRY PICTURE FOR MONDAY MORNING WITH
THE DRYLINE LIGHTING UP ACROSS OUR SOUTHEASTERN ZONES ON MONDAY
AFTERNOON AND PUSHING EAST DURING THE EVENING. TUESDAY APPEARS TO
BE A DOWN DAY FOR CONVECTION THOUGH NWP INDICATES DETERMINISTIC
PRECIPITATION NOISE THOUGH NO CLEAR SIGNAL EXIST. THUS...WILL KEEP
THINGS DRY FOR THE MOST PART. THEREAFTER...ACTIVE WEATHER RETURNS
WEDNESDAY INTO THE WEEKEND WITH AN ATTENDANT THREAT OF SEVERE
WEATHER.

&&

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

$$

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