Area Forecast Discussion
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FXUS64 KLUB 221753
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1253 PM CDT FRI MAY 22 2015

.AVIATION...
LESS THAN IDEAL FLYING CONDITIONS WILL CONTINUE TO PREVAIL AT THE
TERMINALS THIS TAF CYCLE. KPVW AND KLBB MAY SEE A RETURN TO MVFR
CIGS FOR A WHILE THIS AFTERNOON AND EVENING...WITH LESS CERTAINTY
OF SUCH IMPROVEMENTS AT KCDS. REGARDLESS...CIGS ARE EXPECTED TO
PLUNGE BACK INTO IFR TO LIFR TERRITORY TONIGHT INTO EARLY
SATURDAY. IN ADDITION...SHOWER AND THUNDERSTORM CHANCES WILL
INCREASE MARKEDLY AT KLBB AND KPVW AFTER MIDNIGHT AND TOWARD
MORNING AT KCDS. THE CONVECTION COULD HELP SCATTER THE LOWEST
CLOUD DECKS...BUT THEY WILL ALSO BRING THE RISK FOR REDUCED
VISIBILITIES IN HEAVY RAIN.

&&

.PREV DISCUSSION... /ISSUED 1157 AM CDT FRI MAY 22 2015/

UPDATE...
MINOR UPDATE TO ADJUST NEAR-TERM TEMPERATURES AND POPS GIVEN
CURRENT OBSERVATIONS AND TRENDS. THE BATCH OF SHOWERS AND EMBEDDED
THUNDERSTORMS THAT MOVED ACROSS THE AREA EARLIER HAS NOW SHIFTED
EAST OF THE CWA...WITH ONLY A FEW LINGERING LIGHT SHOWERS IN ITS
WAKE. RELATIVELY QUIET CONDITIONS ARE EXPECTED MUCH OF THE
REMAINDER OF THE DAY AS WE ARE SITUATED IN THE SUBSIDENT REGION OF
THE DEPARTING UPPER DISTURBANCE AND MID-LEVEL HEIGHTS RISE
SLIGHTLY. IN ADDITION...ASIDE FROM NEAR THE TX/NM LINE...CLOUDY
SKIES SHOULD PERSIST TODAY KEEPING TEMPERATURES COOL AND SURFACE-
BASED INSTABILITY LIMITED. THAT SAID...GIVEN THE MOIST ATMOSPHERE
IN PLACE...AN ISOLATED ELEVATED SHOWER OR STORM CAN NOT BE
COMPLETELY RULED OUT JUST ABOUT ANYWHERE AND WE HAVE MAINTAINED
MINIMAL POPS THROUGH EARLY EVENING.

THINGS WILL BEGIN TO CHANGE TONIGHT AS THE UPPER LOW OVER SOUTHERN
CALIFORNIA PROGRESSES TOWARD THE FOUR CORNERS AND ANOTHER LEAD
WAVE CURRENTLY OFF THE BAJA QUICKLY APPROACHES FROM THE
SOUTHWEST. STRENGTHENING SOUTHEASTERLY LOW-LEVEL WIND FIELDS WILL
HELP LIFT THE WARM FRONT /AND BETTER MOISTURE AND INSTABILITY/
NORTHWARD INTO THE CWA WHILE LARGE SCALE ASCENT INCREASES. SHOWER
AND THUNDERSTORM ACTIVITY SHOULD BLOSSOM LATE THIS EVENING ACROSS
SOUTHEAST NEW MEXICO INTO THE TRANS-PECOS AND PERMIAN BASIN AND
SPREAD NORTHEAST IN THE AREA THROUGH EARLY SATURDAY MORNING.
INITIALLY...INCREASING INSTABILITY AND DEEP LAYER SHEAR WILL
SUPPORT A SEVERE STORM THREAT. LARGE HAIL WILL BE THE PRIMARY
THREAT...THOUGH AN ISOLATED TORNADO IS NOT OUT OF THE QUESTION
ALONG THE LIFTING WARM FRONT. THE ACTIVITY IS EXPECTED TO GROW
UPSCALE INTO AN MCS AS IT MOVES FROM SOUTHWEST TO NORTHEAST OVER
THE AREA. STRONG MOISTURE ADVECTION AND TRAINING STORMS WILL BRING
A RISK OF LOCALLY HEAVY RAINFALL...INITIALLY ACROSS THE WESTERN
ZONES LATE TONIGHT AND THEN SPREADING INTO THE ROLLING PLAINS
EARLY SATURDAY. IT CURRENTLY APPEARS THAT ONE INCH OF RAIN WILL
BE FAIRLY COMMON WITH 2-3+ INCHES POSSIBLE...ESPECIALLY IN THE
ROLLING PLAINS. GIVEN THE EXPECTED HEAVY RAIN RATES AND ALREADY
SATURATED SOIL...WE COULD BE DEALING WITH SOME FLOODING PROBLEMS
AND WE ARE CONSIDERING A FLOOD WATCH FOR MUCH OF THE CWA FROM
LATE TONIGHT INTO SATURDAY. WE HAVE ALSO ADDED A SEVERE STORM AND
HEAVY RAIN MENTION TO THE GRIDS FOR MOST OF THE FA LATE TONIGHT.
THE UPDATED FORECAST PRODUCTS HAVE BEEN SENT.

PREV DISCUSSION... /ISSUED 647 AM CDT FRI MAY 22 2015/

AVIATION...
BAND OF SHOWERS WITH EMBEDDED THUNDER CONTINUES TO IMPACT KLBB AND
KPVW AND WILL SOON BE TO KCDS. ALTHOUGH PRECIPITATION WILL COME TO
AN END THIS MORNING...IFR CEILINGS WILL LIKELY PERSIST THROUGH
MUCH OF THE DAY FOR ALL SITES AS MOISTURE STREAMS INTO WEST TEXAS
ON SOUTHEAST WINDS. THUNDERSTORMS WILL GENERATE AGAIN THIS EVENING
ACROSS EASTERN NEW MEXICO AND MOVE TOWARD KLBB AND KPVW AFTER
MIDNIGHT. HAVE INSERTED -TSRA MENTION AND LIFR CEILINGS FROM
07-12Z FOR BOTH SITES AS CONFIDENCE IS FAIRLY HIGH IN WIDESPREAD
COVERAGE. KCDS SHOULD REMAIN EAST OF THE BRUNT OF ANY STORMS UNTIL
LIKELY AFTER 12Z SATURDAY.

PREV DISCUSSION... /ISSUED 448 AM CDT FRI MAY 22 2015/

SHORT TERM...
A CLUSTER OF SCATTERED TO NUMEROUS SHOWERS AND EMBEDDED
THUNDERSTORMS CONTINUES THIS MORNING ACROSS THE REGION AHEAD OF A
LEAD IMPULSE DOWNSTREAM OF AN UPPER LOW NEAR SOUTHERN CALIFORNIA.
STRONG MOIST ISENTROPIC ASCENT WAS ALSO PRESENT...HELPING TO PRODUCE
HOURLY RAINFALL RATES OF NEAR A QUARTER OF AN INCH. WILL SEE THE
BRUNT OF THIS ACTIVITY COME TO AN END THIS MORNING FROM WEST TO EAST
AS THE UPPER SUPPORT MOVES INTO THE CENTRAL PLAINS...BUT A STEADY
DOSE OF WARM AIR ADVECTION ATOP A RECOVERING BOUNDARY LAYER WILL
SPELL A LAYER OF LOW STRATUS LIKELY HOLDING STRONG MUCH OF THE DAY
WITH PERHAPS A PEAK OR TWO OF SUNSHINE IN THE SOUTH PLAINS. COULD
SEE AN ELEVATED STORM OR TWO POP THIS AFTERNOON GIVEN THE MOIST
AIRMASS IN PLACE AND PRESENCE OF A NORTHWARD LIFTING WARM
FRONT...BUT HEIGHT RISES ALOFT AND ASSOCIATED POOR MID-LEVEL LAPSE
RATES ABOVE STUBBORN STRATUS SHOULD MUTE ANY WIDESPREAD SIGNIFICANT
CONVECTION. TEMPERATURES SHOULD REBOUND FROM 20-30 DEGREE BELOW
NORMAL READINGS THE PAST TWO DAYS...BUT STILL TOP OUT WELL BELOW
AVERAGE MAINLY IN THE 60S WITH A FEW LOCATIONS IN THE EXTREME
SOUTHERN SOUTH PLAINS AND SOUTHERN ROLLING PLAINS CRACKING 70
DEGREES.

WARM AIR/MOISTURE ADVECTION WILL INCREASE IN EARNEST THIS
EVENING/TONIGHT AS THE AFOREMENTIONED SOUTHERN CALIFORNIA LOW MOVES
TOWARD THE FOUR CORNERS REGION. PWATS INCREASING TO 1.25-1.5 INCHES
WITH DEWPOINTS SURGING INTO THE 60S WILL HELP TO INCREASE CAPES INTO
THE 1-2 KJ/KG RANGE AS MID LEVEL LAPSE RATES STEEPEN COURTESY OF
COOLING TEMPERATURES ALOFT. A 30-40 KNOT LOW LEVEL JET WILL
CONTRIBUTE TO 30-40 KNOTS OF 0-6 KM BULK SHEAR THUS PROVIDING FOR
UPDRAFT ORGANIZATION ALTHOUGH STILL IN ALL LIKELIHOOD REMAINING
ELEVATED. STORM CHANCES WILL BE BEST TONIGHT FROM THE FAR SOUTHWEST
PANHANDLE INTO THE ADJACENT SOUTH PLAINS NEARER THE BRUNT OF THE
FORCING ALOFT. WHILE ALL SEVERE MODES WILL BE POSSIBLE...LARGE HAIL
WILL BE THE PRIMARY HAZARD AS A NARROW WINDOW WILL EXIST FOR
TORNADOES NEAR THE WARM FRONT AND WIND GUSTS DUE TO THE ELEVATED
NATURE OF THESE STORMS. MAY HAVE TO MORE CLOSELY MONITOR THE THREAT
FOR FLOODING INTO THE DAY ON SATURDAY. HAVE OPTED TO REFRAIN FROM
ISSUANCE OF ANY HEADLINES AT THIS TIME GIVEN THE STRENGTHENING DEEP
LAYER SYNOPTIC WIND FIELDS HELPING TO MOVE STORMS ALONG. FLOODING
WILL BE DRIVEN BY MESOSCALE PROCESSES...OWING TO THE DEVELOPMENT OF
ANY ORGANIZED COMPLEX OR MULTIPLE ROUNDS OF STORMS TRAINING OVER THE
SAME AREA. THE UPPER LOW IS ALSO EXPECTED TO WEAKEN AS IT LIFTS
OUT...PLACING THE SOUTH PLAINS AND ROLLING PLAINS REGION IN A
FAVORABLE POSITION TO BE DRY-SLOTTED. THEREFORE...WOULD LIKE TO SEE
HOW SMALLER SCALE PROCESSES PLAY OUT MOVING FORWARD BEFORE ISSUING A
FLOOD WATCH MORE THAN A DAY OUT. ADDITIONALLY...ANALOGS ARE ALSO
SILENT IN TERMS OF ANY FLOOD EVENTS WITH A PATTERN SIMILAR TO THIS.
NONETHELESS...THE MOISTURE AND LIFT WILL INITIALLY BE IN PLACE SUCH
THAT CLOSE MONITORING WILL BE NEEDED.

LONG TERM...
SATURDAY MORNING WILL SEE AN UPPER LOW CENTERED ACROSS NRN AZ/SRN UT
WITH SOUTHWESTERLY FLOW ENTRENCHED ACROSS WEST TEXAS. THIS LOW
WILL SLOWLY LIFT NEWRD INTO NRN CO BY SUNDAY MORNING BEFORE
FILLING ON MONDAY. AS SUCH A COUPLE OF RIBBONS OF VORTICITY WILL
AFFECT THE REGION AS EMBEDDED SHORTWAVES ROTATE ABOUT THE LOW
CENTER. YET STILL...ADDITIONAL SHORTWAVE DISTURBANCES IN THE SRN
BRANCH OF THE JET WILL CONTINUE TO ENHANCE LIFT PERIODICALLY IN
THE EXTENDED AS ACTIVE PATTERN CONTINUES. SATURDAY APPEARS TO BE
CHARACTERIZED BY A RATHER WET MORNING WITH CONVECTION PUSHING OFF
TO THE EAST BY THE AFTERNOON. THIS WILL LIKELY SERVE TO STABILIZE
THE ATMOSPHERE AND LIMIT THE POTENTIAL OF SEVERE CONVECTION TO
SOME EXTENT. STORM ACTIVITY SHOULD CONTINUE INTO SUNDAY FOCUSING
MORE ON THE ROLLING PLAINS BEFORE CONDITIONS DRY OUT FOR MONDAY.
YET...MONDAY NIGHT LOOKS TO SEE A RETURN OF THE ACTIVITY AS
MOISTURE ATTEMPTS TO GAIN A STRONGHOLD. THE GFS LOOKS TO REALLY
OVER-DO THE MOISTURE ADVECTION AND PREFER THE SOLUTION ADVERTISED
BY THE ECMWF AS THIS IS A KNOWN HISTORICAL BIAS OF THE GFS. ALL
IN ALL THE WET PATTERN CONTINUES IN THE LATTER EXTENDED. WILL NOT
TRY TO GET TOO CUTE WITH POPS AS SO MUCH OF THE RAIN WILL BE
DRIVEN BY MESOSCALE PROCESSES SUCH THAT A BLEND OF MODELS IS ABOUT
THE BEST CHOICE.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        55  75  51  75 /  80  50  20  20
TULIA         57  71  53  73 /  70  60  30  30
PLAINVIEW     59  72  55  75 /  70  70  40  30
LEVELLAND     60  76  55  78 /  70  50  40  30
LUBBOCK       61  74  56  78 /  70  50  40  30
DENVER CITY   60  78  55  79 /  70  40  40  30
BROWNFIELD    60  75  55  79 /  70  50  40  30
CHILDRESS     61  72  59  77 /  60  80  50  50
SPUR          60  73  57  78 /  60  70  50  40
ASPERMONT     63  77  60  82 /  50  70  60  60

&&

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

$$

23/33/23


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