263
FXUS64 KLZK 182303 AAA
AFDLZK
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LITTLE ROCK AR
603 PM CDT MON MAR 18 2019
DISCUSSION
UPDATED TO INCLUDE THE 00Z AVIATION DISCUSSION BELOW...
AVIATION
EXPECT THE VFR CONDITIONS TO PERSIST THROUGH THE PERIOD. HIGH
PRESSURE WILL SHIFT TO THE EAST OVERNIGHT INTO TUE...WITH WINDS
BECOMING MORE SRLY.
PREV DISCUSSION
(ISSUED 257 PM CDT MON MAR 18 2019)
SHORT TERM...TONIGHT THRU WEDNESDAY...
NORTHWESTERLY FLOW ALOFT WILL CONTINUE TONIGHT, AS AN OMEGA PATTERN
STARTS TO TAKE SHAPE ACROSS THE WESTERN US. AN ENERGETIC BUT COMPACT
LOW WILL BE DROPPING DOWN OUT OF CANADA, ACROSS THE PLAINS, AND WILL
SPIN DOWN INTO ARKANSAS AT THE END OF THE SHORT TERM.
ORDINARILY I WOULD BE A BIT MORE CONCERNED ABOUT A SYSTEM LIKE
THIS IN MARCH, BUT THERE ARE GOING TO BE SOME SIGNIFICANT
LIMITATIONS TO LOW LEVEL MOISTURE AND INSTABILITY...WHICH HAS BEEN
A RECURRING THEME WITH MANY OF THE PAST SYSTEMS.
THE SURFACE PATTERN REMAINS FIRMLY UNDER HIGH PRESSURE AT THE
MOMENT, AND THE HIGH WILL SLIDE TO THE EAST AND ALLOW A SOUTHERLY
FLOW TO DEVELOP BY TOMORROW AFTERNOON. HOWEVER, THE SOUTHERLY FLOW
DOES NOT EXTEND VERY FAR TO THE SOUTH OF ARKANSAS, AND THERE WILL
NOT BE ANY SUBSTANTIAL CONNECTION TO GULF MOISTURE. AS THE SYSTEM
APPROACHES WEDNESDAY, A COLD FRONT WILL BE PUSHING INTO THE AREA.
WHILE THERE WILL BE QUITE A BIT OF LIFT AVAILABLE WITH THIS
SYSTEM, THE THERMODYNAMICS AND MOISTURE LEVELS ARE NOT VERY
IMPRESSIVE. FOR THE TIME BEING I AM LEAVING THE EXISTING MENTION
OF SHOWERS...SANS THUNDER - IN THE FORECAST GRIDS FOR NOW.
LONG TERM...WEDNESDAY NIGHT THRU SUNDAY NIGHT...
TO BEGIN THE PERIOD, H500 OMEGA HIGH WILL BE SITUATED OVER THE
NRN PLAINS. ON THE ERN PERIPHERY OF THE HIGH, AN EMBEDDED IMPULSE
WILL BE MOVING THROUGH THE FLOW TRAVERSING NE AR. AT THE SURFACE,
A WEAK FRONTAL BOUNDARY WILL BE SWEEPING THROUGH THE STATE
PROVIDING WEAK LIFT TO PROMOTE THE DEVELOPMENT OF LIGHT
PRECIPITATION. BEST POP CHANCES WILL RESIDE ACROSS NERN PORTIONS
OF THE STATE WHERE AMOUNTS OF QUARTER OF AN INCH OR LESS ARE
EXPECTED. HEADING INTO THURSDAY THE OMEGA HIGH AXIS SHIFTS FURTHER
E TOWARDS AR. SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION
FROM THE PLAINS HOWEVER, THE AIR MASS BEHIND THE BOUNDARY WILL
REMAIN FAIRLY MILD BUT WILL PROVIDE A RE-ENFORCING SHOT DRIER AIR
VIA LOWER DEW POINTS.
ON FRIDAY, THE UPPER LEVEL RIDGE AXIS BEGINS SHIFTING E OF AR, AT
THE SURFACE, HIGH PRESSURE BEGINS TO MOVE AWAY FROM THE REGION AS
SERLY WINDS RETURN. OUT W, A CLOSED UPPER LOW BEGINS TO EJECT
TOWARDS THE ROCKIES. BEYOND FRIDAY EVENING, MODEL GUIDANCE BECOMES
MORE UNCERTAIN TO HOW THE UPPER LOW OVER THE DESERT SW EVOLVES ON
ITS EWRD TREK. BY LATE SATURDAY, A SHEARED AXIS SETS UP BETWEEN
UPPER RIDGING OVER THE TN VALLEY AND TROUGHING OVER THE PLAINS.
SWERLY FLOW INCREASES ACROSS THE REGION WITH BROAD ASCENT
OVERSPREADING FROM SW TO NE. MOISTURE ADVECTION WILL INCREASE ACROSS
WRN PORTIONS OF THE CWA INITIALLY BEFORE SPREADING EWRD AS MOISTURE
IS PULLED NWRD INTO THE SURFACE LOW OVER THE PLAINS. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE WEEKEND WITH THE HELP
OF COMPACT IMPULSES PIVOTING AROUND THE BASE OF THE TROUGH AND
THROUGH THE MEAN SW TO NE ORIENTED FLOW. TEMPERATURES WILL REMAIN IN
THE 60S AND 70S FOR HIGHS AND LOWS RANGING FROM THE MID 30S TO MID
50S.
LZK WATCHES/WARNINGS/ADVISORIES
NONE.
AVIATION...62
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