000
FXUS64 KLZK 202349
AFDLZK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
649 PM CDT MON MAY 20 2013

.DISCUSSION...

UPDATED FOR THE 00Z AVIATION DISCUSSION BELOW.

&&

.AVIATION...

TOUGH FORECAST THIS EVENING. LINE OF CONVECTION APPROACHING FROM
OKLAHOMA LOOKS TO BE HOLDING TOGETHER PRETTY GOOD AS OF 2345Z
THIS EVENING. HAVE INCLUDED SOME TEMPO TSRA AT NORTHERN SITES AS
IT LOOKS THAT IT WILL AFFECT KHRO AND KBPK. IT WAS ORIGINALLY
THOUGHT THE LINE WOULD WEAKEN AND SLOW IT/S EASTWARD
PROGRESSION...AND THAT INDIVIDUAL STORMS/SHOWERS WOULD THEN MOVE
NORTHEAST WITH THE MEAN STEERING FLOW. HAVE TRENDED THE TAFS
OVERALL IN THIS DIRECTION...BUT DID GO AHEAD AND MENTION VCSH AT
KHOT AND KADF THIS EVENING IN CASE THE LINE PROGRESSES FURTHER
INTO ARKANSAS THAN THOUGHT. WILL AMEND IF/WHEN NECESSARY IN THAT
CASE. MVFR CONDITIONS ARE EXPECTED MOST PLACES TONIGHT AND SHOULD
SEE VCSH SITUATIONS AT NORTHERN AND WESTERN SITES THROUGH THE
OVERNIGHT HOURS. MORE WIDESPREAD SHOWERS AND STRONG THUNDERSTORMS
WILL ERUPT ACROSS ARKANSAS TOMORROW. WENT WITH VCTS FOR ALL SITES
TO ACCOUNT FOR THIS AS TIMING AND PLACEMENT NOT CERTAIN ENOUGH TO
INCLUDE PREVAILING THUNDER AND MVFR/IFR CONDITIONS DURING LAST 6-8
HOURS OF THE TAF PERIOD. BUT REST ASSURED...THEY WILL BE AFFECTING
MOST ALL TERMINALS TOMORROW.

&&

.PREV DISCUSSION... /ISSUED 230 PM CDT MON MAY 20 2013/

..SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT...
A VIGOROUS UPPER LOW WAS POSITIONED ACROSS THE NORTHERN PLAINS THIS
AFTERNOON WITH A SFC FRONT EXTENDING FROM MN SOUTHWARD INTO CENTRAL
OK. THIS FRONT WILL SLOWLY ADVANCE INTO THE STATE BY TOMORROW
MORNING.

CONCERN ATTM IS FOR THE POTENTIAL FOR SEVERE WEATHER ACROSS PORTIONS
OF THE AREA THIS AFTERNOON THROUGH TOMORROW NIGHT. THE ATMOSPHERE
ACROSS THE CWA IS QUITE UNSTABLE THIS AFTERNOON...WITH SFC BASED
CAPE VALUES ARE AROUND 3400 J/KG. 18Z KLZK SOUNDING APPEARS TO HAVE
SOME DATA ERRORS BUT THE CAP APPEARS TO HAVE ERODED SIGNIFICANTLY.
STORMS ARE JUST STARTING TO FIRE UP IN OK AHEAD OF THE FRONT AND
SUPERCELLS ARE A CONCERN. I AM CONCERNED THAT SUPERCELLS MAY FORM OR
TRACK INTO THE WRN AND NWRN PORTIONS OF THE CWA TONIGHT. WITH THE
ATMOSPHERE SO UNSTABLE I AM ALSO CONCERNED ABOUT THE EFFECT OF
OUTFLOW BOUNDARIES.

LOOKING AT THE 18Z HODOGRAPH...LOW LEVEL WINDS ARE MORE SWLY AND THE
HODOGRAPH IS NOT QUITE AS OMINOUS...BUT I AM STILL CONCERNED ABOUT
THE POSSIBILITY OF TORNADOES TONIGHT...MAINLY IN THE NWRN ZONES. AS
STORMS ADVANCE EASTWARD THEY MAY TRANSITION INTO MORE OF A SQUALL
LINE TYPE EVENT.

QPF VALUES HAVE BEEN TOUGH TO NAIL DOWN BUT HEAVY RAIN FROM SLOW
MOVING STORMS AND TRAINING EFFECTS WILL BE A CONCERN...PRIMARILY IN
THE NWRN ZONES TONIGHT. I HAVE BEEN ON THE FENCE REGARDING THE
ISSUANCE OF A FLASH FLOOD WATCH FOR THOSE AREAS TONIGHT. AFTER MUCH
DEBATE...I WILL GO AHEAD AND ISSUE FOR THOSE AREAS TONIGHT THROUGH
TOMORROW NIGHT. ANOTHER WATCH MAY BE NEEDED FARTHER SOUTH TOMORROW.

AS THINGS PROGRESS EASTWARD STORMS WILL CONTINUE ACROSS THE CWA
THROUGH TOMORROW NIGHT. THERE ARE STILL A LOT OF UNCERTAINTIES ABOUT
THE SEVERITY OF THE EVENT AND THE TIMING OF THUNDERSTORMS. IN
SHORT...THERE LOOKS TO BE A GOOD POSSIBILITY OF SEVERE WEATHER
ACROSS MUCH OF THE CWA TOMORROW AS WELL...ALTHOUGH THE TORNADO
THREAT LOOKS TO BE LOWER...WITH THE PRIMARY THREAT BEING STRAIGHT
LINE WINDS AND HAIL. 53

LONG TERM...FRIDAY THROUGH MONDAY...
ABOVE AVERAGE FORECAST CONFIDENCE WITH REGARD TO MEDIUM RANGE MODEL
SOLUTIONS EXISTS FOR THIS PERIOD.  SURFACE HIGH PRESSURE WILL BE
BUILDING THROUGH MOST OF THE MISSISSIPPI VALLEY EARLY IN THIS
PERIOD...AND WILL PROMOTE DRY CONDITIONS. INCREASING MID LEVEL
HEIGHTS FROM THE SOUTHERN PLAINS...THROUGH THE MID SOUTH WILL
PROMOTE CONTINUED DRY CONDITIONS...AS WELL AS AS WARMING TREND
TOWARDS THE END OF THE PERIOD. 55

&&

.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR     85  70  78  62 /  10  50  90  60
CAMDEN AR         89  72  84  69 /  10  10  60  60
HARRISON AR       82  66  72  57 /  10  80  80  40
HOT SPRINGS AR    88  71  80  67 /  10  20  70  60
LITTLE ROCK   AR  88  72  84  68 /  10  20  60  60
MONTICELLO AR     90  72  87  69 /  10  10  60  60
MOUNT IDA AR      87  71  79  63 /  10  40  80  60
MOUNTAIN HOME AR  83  67  74  59 /  10  80  90  60
NEWPORT AR        87  71  81  63 /  10  30  80  70
PINE BLUFF AR     89  72  87  68 /  10  10  60  50
RUSSELLVILLE AR   85  70  79  61 /  10  60  80  60
SEARCY AR         87  72  81  64 /  10  30  70  60
STUTTGART AR      89  72  84  67 /  10  10  60  60
&&

.LZK WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR BAXTER-BOONE-
JOHNSON-LOGAN-MARION-NEWTON-POLK-POPE-SCOTT-SEARCY-YELL.

&&

$$


AVIATION...64