Area Forecast Discussion
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FXUS64 KLUB 020437
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1137 PM CDT FRI MAY 1 2015

.AVIATION...
VFR WITH 10-15 KT S-SE WINDS BECMG GUSTY BY LATE SAT MORNING.

&&

.PREV FORECAST DISCUSSION... /ISSUED 339 PM CDT FRI MAY 1 2015/

SHORT TERM...
WEAK UA RIDGING CONTINUED TO DOMINATE ACROSS THE SOUTHERN PLAINS
LATE THIS AFTN...AND WILL REMAIN PRESENT /ALBEIT FLATTENING A BIT/
THROUGH TOMORROW. LOOKING AT THE SFC...A COLD FRONT EARLIER THIS
MORNING WAS NOTED ACROSS NERN NM AND THE NWRN TX PANHANDLE BUT HAS
SINCE RETREATED NWRD COURTESY OF LEE TROUGHING PROMOTING SLIGHTLY
BREEZY S-SE SFC WIND SPEEDS OF 10-20 MPH PER 20Z METARS. TEMPS HAVE
WARMED INTO THE LOWER 80S MAKING FOR A SEASONABLY WARM START TO THE
MONTH OF MAY. WEAK EMBEDDED DISTURBANCES ROUNDING THE TOP OF THE UA
RIDGE COUPLED WITH TOPOGRAPHIC EFFECTS HAVE LED TO THE DEVELOPMENT
OF STORMS FIRING UP ACROSS THE MOUNTAINOUS TERRAIN OF NERN NM AND
SERN CO LATE THIS AFTN. 10-15 KTS OF SWRLY MEAN FLOW WILL MAINTAIN
THE PRECIP TO OUR NORTH THIS EVENING INTO TONIGHT...THOUGH SOME
CLOUD DEBRIS COULD BRUSH ACROSS OUR NRN ZONES. WIND SPEEDS WILL
DECLINE SHORTLY AFTER SUNSET WHILST SFC WINDS VEER TO THE SW
OVERNIGHT...MAKING FOR MILD LOW TEMPS /50S/. SATURDAY...A TIGHTENED
PRESSURE GRADIENT PROVIDED BY SFC LEE TROUGHING WILL BRING ABOUT THE
RETURN OF BREEZY CONDITIONS /15-20 MPH/...BUT THIS TIME FROM THE S-
SW. THIS DOWNSLOPING WIND EFFECT WILL LIKELY RESULT IN HIGH TEMPS A
FEW DEGREES WARMER THAN TODAY /MIDDLE 80S/. ONCE AGAIN...STORMS WILL
FIRE UP ACROSS THE MOUNTAINS TERRAIN OF NM AND CO COURTESY OF WEAK
EMBEDDED DISTURBANCES AND TOPOGRAPHIC EFFECTS...HOWEVER 15-20 KTS OF
W-SW MEAN FLOW COULD PERHAPS ENCOURAGE LINGERING STORMS TO NEAR THE
FAR SWRN TX PANHANDLE/NWRN SOUTH PLAINS BY THE EVENING HOURS. /29

LONG TERM...
NOT TOO MUCH HAS CHANGED WITH THE EVOLUTION OF A MOIST UPPER
TROUGH EXPECTED TO BRING DECENT THUNDER AND RAIN CHANCES TO THE
SOUTHERN PLAINS IN THE LATE SUNDAY THROUGH EARLY WEDNESDAY TIME-
FRAME. UPPER RIDGE AXIS SHIFTING JUST EAST SUNDAY AFTERNOON WILL
ALLOW INCREASING LOW LEVEL SOUTHERLY COMPONENTS WITH PRECIPITABLE
WATER VALUES JUMPING ABOVE NORMAL LEVELS OVER 0.75 INCH SUNDAY
NIGHT...THEN AN INCH TO AN INCH AND A THIRD BY MONDAY NIGHT.
INITIAL IMPULSE LIFTING MAINLY JUST TO THE NORTH SUNDAY EVENING
MAY HAVE ENOUGH FLOW TO PULL CONVECTIVE ACTIVITY FROM NEAR THE
SURFACE TROUGH-DRYLINE LOCATION CLOSE TO THE NEW MEXICO BORDER
INTO THE CENTRAL PANHANDLE AND SOUTH PLAINS. CAPPING SHOULD MOSTLY
ERODE BY LATE SUNDAY SO MAIN QUESTION THEN WILL BE HOW MATURE A
COLD POOL DEVELOPS...IF ANY...ALONG WITH ONLY MODEST MID LEVEL
FLOW OF 25-30 KNOTS...TO PUSH CONVECTION TO THE EAST BEFORE
NIGHTTIME COOLING PUTS KIBOSH ON CHANCES LATER IN THE NIGHT. FEEL
THIS IS GOOD STILL FOR A LOW CHANCE FAVORING MAINLY WESTERN
COUNTIES SUNDAY EVENING AS UNCERTAINTIES REMAIN.

MONDAY THE UPPER FLOW WILL BACK AS LOW PRESSURE ALOFT DIGS INTO
THE DESERT SOUTHWEST. A WEAK THOUGH FAIRLY WELL DEFINED UPPER
IMPULSE SHOULD LIFT NORTH-NORTHEAST THROUGH THE HIGH PLAINS LATE
IN THE DAY. THE BACKED FLOW WILL PULL THE DRYLINE FURTHER WEST
PERHAPS TO THE PECOS VALLEY OR EVEN TO THE MOUNTAINS...AND THERE
DOES NOT LOOK RIGHT NOW LIKE VERY MUCH FLOW TO PULL THIS OUT
MONDAY NIGHT. BUT MOISTURE WILL BE DEEP AND ENVIRONMENT STILL
PERHAPS WEAKLY CAPPED SO IF SURFACE HEATING IS SUFFICIENT...THERE
COULD BE DISCREET CELLS DEVELOPING TO THE EAST OF THE DRY LINE
LATE MONDAY AS LIFT SPREADS OVERHEAD. WE INHERITED SOLID CHANCES
AND SUPERBLEND REMAINED HIGH FOR THIS PERIOD...AGAIN FAVORING
WESTERN COUNTIES LATE MONDAY THEN SPREADING EAST AS A COLD POOL
MAY DEVELOP TO ENCOURAGE MORE EASTERN PROPAGATION. BUT IT STILL
REMAINS UNCERTAIN IF ACTIVITY MONDAY NIGHT WILL IN FACT BE ABLE TO
SPREAD THROUGH THE AREA THOUGH THERE APPEARS TO BE A BETTER SHOT
THAN PREVIOUS NIGHT.

THIS UNCERTAINTY LEADS INTO TUESDAY WHEN THE UPPER LOW SHOULD LIFT
AS AN OPEN WAVE JUST TO OUR NORTHWEST. SURFACE PRESSURE PATTERN
SHOULD TIGHTEN AND WE EXPECT THE TROUGH-DRYLINE PULL EAST INTO OUR
AREA AS WELL. ASSUMING AIRMASS NOT TOO WORKED OVER FROM STORMS
MONDAY NIGHT...WE SHOULD THEN SEE SOLID DEVELOPMENT OF CONVECTIVE
SYSTEMS TUESDAY AFTERNOON INTO EVENING ALONG WITH RISK OF SEVERE
AND HEAVY RAIN-LOCAL FLOODING. WHETHER STORMS PREFER MONDAY OR
TUESDAY EITHER WAY SHOULD RESULT IN DECENT WIDESPREAD
PRECIPITATION COVERAGE FOR THE TEXAS SOUTH PLAINS REGION BEFORE
THE LATER WAVE PULLS NORTHEAST EARLY WEDNESDAY. LATEST HPC TOTAL
PRECIPITATION AMOUNTS STILL SHOW A MAXIMUM OF 2 INCHES OR MORE
OVER CENTRAL AND EASTERN SOUTH PLAINS...WITH AN INCH OR MORE
ELSEWHERE DURING THIS PERIOD.

ONE DAY OF MODEST DRYING SEEMS PLAUSIBLE WEDNESDAY...THOUGH AS
NOTED BY EARLIER SHIFT THE UPPER FLOW MAY NOT STEER LOW LEVEL FLOW
INTO TOO MUCH LOW LEVEL DRYING. AND THERE WILL BE A RISK FOR DRY-
LINE RECOVERING BACK INTO CENTRAL AREAS BY LATE WEDNESDAY. BUT
DYNAMICS THAT DAY SHOULD BE LESS AND DEEP MOISTURE ALSO DEPLETED.
LATER IN THE WEEK DETAILS BECOME MORE MUDDLED AS ANOTHER UPPER
TROUGH LOOKS TO DIG INTO THE SOUTHWEST WITH BACKING FLOW UP ACROSS
THE SOUTHERN PLAINS. THIS SHOULD SUPPORT AT LEAST A CHANCE OF
THUNDER MAINLY CENTRAL AND EASTERN AREAS. SOLUTIONS HAVE BACKED
OFF ON EJECTING THIS LOW QUITE SO STRONGLY NEXT FRIDAY OR EARLY
SATURDAY...SO ALSO DO NOT SHOW MUCH CHANCE OF A SURFACE FRONT INTO
THE AREA EITHER. BUT THIS ALSO MEANS WE WILL BE MORE LIKELY TO
RETAIN MOISTURE. ANYWAY...LOTS SAID JUST TO STATE THAT IS APPEARS
LIKE AN ACTIVE PATTERN IS STILL ON TRACK IN THE COMING WEEK.
/05 RMCQUEEN

&&

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

$$

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