193
FXUS64 KAMA 141101
AFDAMA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AMARILLO TX
601 AM CDT FRI MAY 14 2021
AVIATION
FOR THE 12Z TAFS:
VFR CONDITIONS ARE EXPECTED AT THE TERMINALS THROUGHOUT THE VALID
TAF PERIOD. THE MAIN CONCERN TODAY WILL BE THE THUNDERSTORM
POTENTIAL LATE THIS AFTERNOON AND EVENING WHICH MAY END UP
IMPACTING ALL THREE TERMINALS. IF THUNDERSTORMS IMPACT THE
TERMINALS, THERE COULD BE A CHANGE TO MVFR AT THAT POINT WITH ANY
INTENSE RAINFALL IMPACTING VISIBILITIES. OTHERWISE, STORMS SHOULD
RACE THROUGH PRETTY QUICK, SO IF THE TERMINALS ARE IMPACTED, IT
WILL ONLY BE FOR A COUPLE HOURS MORE THAN LIKELY.
GUERRERO
PREV DISCUSSION
/ISSUED 347 AM CDT FRI MAY 14 2021/
SHORT TERM (TODAY THROUGH TOMORROW NIGHT)...
WE BEGIN OUR ACTIVE WEATHER PATTERN ACROSS THE PANHANDLES TODAY.
BOTH TODAY AND TOMORROW WILL HAVE THE POTENTIAL FOR SEVERE
THUNDERSTORMS ACROSS THE AREA. WE HAVE SOME LIMITING FACTORS WHICH
WE WILL DISCUSS, BUT OVERALL CONFIDENCE IS MODERATE (SCALE OF
LOW, MODERATE, AND HIGH) FOR SEVERE WEATHER TO DEVELOP OVER
PORTIONS OF THE FORECAST AREA. THE MAIN THREATS WILL BE WIND AND
HAIL.
AT A GLANCE SEVERE WEATHER TIMING/THREATS:
* TODAY/FRIDAY: 4PM TO MIDNIGHT
- ENTERING THE WESTERN PANHANDLES AND QUICKLY PUSHING EAST
- HAIL: AROUND QUARTER SIZE
- WIND: 60 - 70 MPH
- TORNADO: UNLIKELY
* TOMORROW/SATURDAY: 3PM THROUGH THE OVERNIGHT PERIOD
- ANOTHER WEST TO EAST PROGRESSION
- HAIL: UP TO GOLF BALL SIZE
- WIND: 60 - 75 MPH
- TORNADO: UNLIKELY
FURTHER DETAILS:
LATER TODAY, AN H5 LOW WILL BEGIN TO MAKES IT TREK SOUTHWARD
ACROSS CALIFORNIA, AND IT SHOULD EVENTUALLY BECOME A CLOSED LOW
BY LATE THIS EVENING. DOWNSTREAM, AHEAD OF THE MAIN DISTURBANCE, A
SHORTWAVE WILL KICK OUT OVER THE PANHANDLES LATE THIS
AFTERNOON/EVENING. TO OUR WEST, OVER THE HIGHER TERRAIN,
CONVECTIVE TEMPERATURES MAY ALLOW FOR THUNDERSTORMS TO INITIATE
OVER EASTERN NEW MEXICO BY MID AFTERNOON, AND THESE STORMS SHOULD
GET GOING EASTWARD AS THAT SHORTWAVE MAKES ITS WAY TOWARDS THE
SOUTHERN PLAINS. WE ARE LACKING RETURN FLOW TODAY, AND FORECAST
SOUNDINGS DEPICT AN INVERTED-V PROFILE TODAY WITH SUFFICIENT HIGH
BASED INSTABILITY. LOW/MID LEVEL FLOW IS RATHER WEAK, SO
SHEAR/HELICITY PARAMETERS ARE ALSO WEAK. WE DO HAVE A VEERING WIND
PROFILE IN THE LOW/MID LEVELS, BUT THE SPEED PARAMETER HERE IS
RATHER WEAK. IN OTHER WORDS, THE LOW LEVEL WIND PATTERN IS SO
WEAK, AND THE LCL HEIGHTS ARE GOING TO BE SO HIGH, IT'S GOING TO
BE DIFFICULT TO SUPPORT A THREAT FOR TORNADOES WITHOUT SOME
SERIOUS MESOSCALE MODIFICATIONS TO THE ATMOSPHERE. MLCAPE AROUND
500-1500 J/KG WILL BE PRESENT TODAY ALONG WITH DOWNDRAFT CAPE
AROUND 500-1200 J/KG. THIS COULD VERY WELL LEAD TO DAMAGING WIND
GUSTS AND SEVER HAIL. HODOGRAPHS ARE SMALL AND RESEMBLE A
MULTICELL/SPLIT/PULSE TYPE OF STORM MODE TODAY. THIS COULD LEAD
TO SOME NUISANCE ON THE WARNING DESK FOR THE RADAR OPERATOR AS
STORMS PULSE AND STRUGGLE TO MAINTAIN AN UPDRAFT AND/OR COLLAPSE.
HOWEVER, IT SHOULD GET EASIER FOR WARNINGS AS STORMS MAY BECOME
MORE COLD POOL DOMINANT AND LINEAR IN NATURE AS THEY PROGRESS EAST
ACROSS THE PANHANDLES IN THE EVENING HOURS. TODAY, LEANING MORE
ON THE WIND THREAT GIVEN HOW QUICKLY STORMS COULD BECOME LINEAR
AND THE AMOUNT OF DOWNDRAFT CAPE WITH THE INVERTED-V PROFILES.
MOVING AHEAD TO TOMORROW, A VERY SIMILAR SETUP REGARDING THE UPPER
LEVELS AS ANOTHER SHORTWAVE KICKS OUT AHEAD OF THE MAIN H5 LOW
(NOW ENTERING SOCAL). OVERALL, A LOT OF THE PARAMETERS ARE SIMILAR
TO FRIDAY, BUT WE WILL SEE HIGHER MLCAPE VALUES. THEREFORE, THE
THOUGHT IS WE WILL SEE HIGHER THREAT LEVELS OF HAIL, BUT AGAIN THE
SHEAR PARAMETERS ARE NOT THE MOST IDEAL FOR UPDRAFT MAINTENANCE.
MLCAPE AROUND 2000 J/KG WILL BE PRESENT WITH DOWNDRAFT CAPE
SIMILAR TO FRIDAY. THAT AMOUNT OF CAPE MAY BE ENOUGH TO OVERCOME
SOME OF THE FEEBLE SHEAR PARAMETERS, SO HAIL UP TO GOLF BALL SIZE
MAY BECOME EVIDENT. 700MB THETA-E VALUES ARE HIGHER TOMORROW THAN
FRIDAY, SO THUNDERSTORM COVERAGE MAY BE GREATER ACROSS THE
PANHANDLES, BUT AGAIN IT LOOKS LIKE UNORGANIZED
MULTICELL/SPLIT/PULSE TYPE STORM MODE BASED ON HODOGRAPHS. MEAN
FLOW AROUND 500MB IS VERY WEAK, SO STORMS ARE LIKELY GOING TO BE
SLOW MOVERS, AND THIS COULD LEAD TO A HIGHER CHANCE FOR DOWNBURST
AS UPDRAFTS COLLAPSE. WIND THREAT LOOKS TO BE HIGHER TODAY AS
WELL COMPARED TO FRIDAY. WITH THAT SAID, IT MAY BE ANOTHER
DIFFICULT WARNING DAY AS THE PULSE NATURE OF THE STORMS MAY BECOME
A NUISANCE. IN FACT, ITS LIKELY GOING TO BE MORE OF A NUISANCE
THAN FRIDAY.
GUERRERO
LONG TERM...SUNDAY THROUGH THURSDAY...
SYNOPSIS: ACTIVE WEATHER WITH POTENTIAL FOR SEVERE STORMS WILL
CONTINUE THROUGH AT LEAST MONDAY, WITH STORM CHANCES CONTINUING
THROUGH THURSDAY. DETAILS COULD CHANGE IN TERMS OF STORM SEVERITY,
COVERAGE, AND TIMING BASED ON SEVERAL FACTORS (EXPLAINED MORE
BELOW). OTHERWISE, EXPECT TEMPERATURES NEAR AVERAGE ON SUNDAY TO
SLIGHTLY BELOW AVERAGE FOR MOST OF NEXT WEEK DEPENDING ON
PLACEMENT OF A COLD FRONT AND EXTENT OF LOW CLOUDS.
DETAILS: AN UPPER LEVEL CLOSED LOW IS EXPECTED TO TREK ACROSS THE
SOUTHERN TIP OF NV ON SUNDAY, ENDING UP OVER NORTHERN AZ BY MONDAY
AFTERNOON. THE LATEST DETERMINISTIC MODELS AND ENSEMBLES ARE IN
DECENT AGREEMENT WITH THE UPPER SYSTEM THROUGH THIS TIME, BUT
START TO DIVERGE FROM ONE ANOTHER GOING INTO TUESDAY AND
WEDNESDAY. MODELS HAVE TRENDED A BIT SLOWER, WITH THE SYSTEM
BECOMING MORE ELONGATED AND NEGATIVE TILT AS IT MOVES OUT OVER
THE SOUTHERN GREAT PLAINS TUESDAY INTO WEDNESDAY. GIVEN THIS, THE
PANHANDLES LOOK TO REMAIN IN RETURN FLOW WITH AT LEAST SOME FORM
OF DIFFUSE DRYLINE / SFC TROUGH MIXING EAST EACH AFTERNOON UNTIL
THIS SYSTEM FINALLY TRANSLATES ACROSS THE AREA BY MID WEEK. A COLD
FRONT WILL ALSO BE IN PLAY - MORE SO ON MONDAY AND TUESDAY AS A
MORE PRONOUNCED SURFACE LOW ATTEMPTS TO DEVELOP IN EASTERN NM.
THE UNFORTUNATE TRUTH IS THAT THE MODELS ARE GOING TO STRUGGLE
WITH THE PLACEMENT OF SURFACE FEATURES AND RESULTING CONVECTION
SUNDAY AND MONDAY, ESPECIALLY CONSIDERING HOW SLOW THE UPPER
SYSTEM IS ADVANCING EAST. EXCEPT FOR SOME LIMITED DYNAMIC LIFT
ASSOCIATED WITH MINOR LEAD SHORTWAVES SUNDAY AND MONDAY, LARGE
SCALE LIFT WILL MAINLY STAY WEST OF THE PANHANDLES UNTIL AT LEAST
MONDAY NIGHT IF NOT TUESDAY. 500MB HEIGHTS ACTUALLY INCREASE SOME
ON SUNDAY IN PRESENCE OF WEAK RIDGING PRIOR TO THE ARRIVAL OF A
LEAD SHORTWAVE. CONVECTIVE INITIATION IS LIKELY TO OCCUR SUNDAY
AFTERNOON AND MONDAY AFTERNOON ALONG THE DRYLINE AS CONVECTIVE
TEMPERATURES ARE REACHED. A COLD FRONT MAY ALSO HELP TRIGGER
STORMS, BUT MODELS DIFFER ON HOW FAR SOUTH THE FRONT WILL BE
SUNDAY AND ALSO WHERE THE BEST DRYLINE CONVERGENCE WILL BE (OLD
OUTFLOW BOUNDARIES AND RECOVERY ISSUES MAY ALSO PLAY HAVOC WITH
THE FORECAST - AS MODELS DON'T RESOLVE THESE THINGS WELL). ANY
STORMS THAT DO FORM WILL BE IN ENVIRONMENT WITH UPPER 50S TO LOW
60S SFC DEW POINTS, MLCAPE AROUND 1000 TO 2000 J/KG, AND STEEP
LAPSE RATES. EFFECTIVE SHEAR REMAINS PRETTY LOW (20 TO 30 KNOTS)
AS THE BETTER WIND FIELDS STAY WEST OF THE PANHANDLES UNTIL LATE
MONDAY. OVERALL, THE MAIN THREAT WILL BE LARGE HAIL (GOLF BALL OR
EVEN SLIGHTLY LARGER GIVEN COOL TEMPS ALOFT) AND DAMAGING WINDS
GIVEN HIGH BASES AND LARGE DCAPE VALUES. THE TORNADO THREAT WILL
REMAIN LOW GIVEN HIGH LCLS AND LACKING LOW LEVEL SHEAR, BUT CAN'T
COMPLETELY BE RULED OUT GIVEN BOUNDARIES IN PLAY.
RIGHT NOW, DETERMINISTIC MODELS DO SHIFT THE FRONT THROUGH THE
PANHANDLES BY MONDAY AFTERNOON, WHICH SUGGEST LIFT WILL BE MORE
IN THE FORM OF UPSLOPE FLOW OVER THE HIGHER TERRAIN. THIS IS ALSO
WHEN BETTER LARGE SCALE LIFT APPROACHES WITH PVA AND HEIGHT FALLS
OCCURRING LATE MONDAY THROUGH TUESDAY. SO EVEN IF THE PANHANDLES
IS BEHIND THE COLD FRONT MONDAY INTO TUESDAY, SHOWERS AND ELEVATED
STORM CHANCES LOOK REALLY GOOD, AND SEVERE STORMS MAY BE MORE
LIMITED TO HAIL IF ENOUGH ELEVATED INSTABILITY CAN MATERIALIZE IN
A BETTER SHEAR ENVIRONMENT. IF FOR SOME REASON THE COLD FRONT
HANGS UP TO THE NORTH, THEN BETTER ORGANIZED SURFACE BASED STORMS
WOULD BE POSSIBLE GIVEN INCREASED DEEP LAYER SHEAR. EITHER WAY,
ANY STORMS THAT FORM DURING THIS TIME FRAME MAY POSE A FLASH
FLOOD THREAT OVER AREAS THAT RECEIVE HEAVY RAIN ON DAYS PRIOR.
WARD
AMA WATCHES/WARNINGS/ADVISORIES
TX...NONE.
OK...NONE.
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