dhweather wrote:FWD AFD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
342 PM CDT TUE APR 22 2014
.DISCUSSION...
WITH MID- AND UPPER-LEVEL RIDGING ALOFT...IT WAS A PLEASANT
AFTERNOON ACROSS NORTH AND CENTRAL TEXAS...WITH SLIGHTLY ABOVE
NORMAL TEMPERATURES. THESE RIDGE AXES WILL SOON PASS EAST OF THE
AREA AS THE STORM SYSTEM NOW OVER CALIFORNIA SWINGS INTO THE
INTERMOUNTAIN WEST. AS ITS ASSOCIATED MID-LEVEL JET EXITS THE
HIGH TERRAIN AND HEADS INTO THE CENTRAL PLAINS...LEE TROUGHING
WILL BE INDUCED AT THE SURFACE. THIS WILL RAPIDLY CREATE A DRYLINE
THROUGH THE PANHANDLE AND SOUTH PLAINS ON WEDNESDAY...ALONG
WHICH THUNDERSTORMS WILL LIKELY DEVELOP. THESE STORMS WILL HAVE A
TENDENCY TO MOVE EAST AND NORTHEAST AWAY FROM THE BOUNDARY...BUT
THE ACTIVITY WILL LIKELY BE WELL WEST OF NORTH TEXAS BY NIGHTFALL
WEDNESDAY EVENING. THE CONVECTION WILL BE ENTERING AN AREA OF
INCREASING CINH WITH A STABILIZING BOUNDARY LAYER. THE MAIN UPPER
LOW WILL SKIRT THE CANADIAN BORDER...BUT A TRAILING SHORTWAVE MAY
HELP MAINTAIN AT LEAST ELEVATED CONVECTION INTO NORTH TEXAS
WEDNESDAY NIGHT INTO THURSDAY MORNING. THIS IS NOT THE IDEAL TIME
OF DAY FOR SEVERE STORMS...BUT WITH A 30- TO 40-KT LLJ BENEATH
CONSIDERABLE MID-LEVEL LAPSE RATES AND INCREASING FORCING FOR
ASCENT...THERE MAY BE SOME UPDRAFTS CAPABLE OF SUSTAINING LARGE
HAIL. REGARDLESS...3RD-PERIOD POPS ARE LOW AND EMPHASIZE LACK OF
CONFIDENCE THAT THE STORMS WILL BE ABLE TO SURVIVE INTO NORTH
TEXAS. THE GFS/GEM SOLUTIONS HAVE THE TRAILING SHORTWAVE EAST OF
OUR AREA BY THURSDAY AFTERNOON...BUT THE LATEST NAM/ECMWF
SOLUTIONS ARE A BIT SLOWER. AS A RESULT...WILL MAINTAIN SOME LOW-
END POPS IN THE FAR EAST THURSDAY AFTERNOON.
THERE IS STILL SOME UNCERTAINTY ABOUT THE STORM SYSTEM THAT WILL
ENTER THE PLAINS THIS WEEKEND...BUT THERE IS GENERALLY GOOD
AGREEMENT THAT THE COMPACT MID-LEVEL LOW WILL MOVE NORTH AS IT
EMERGES FROM THE HIGHER TERRAIN TO THE WEST. THIS WILL RESULT IN
RAPID INTENSIFICATION AS THE FEATURE BOTH STRETCHES VERTICALLY AND
MOVES POLEWARD. THE GREATER UNCERTAINTY IS RELATED TO HOW MUCH
ENERGY IS AVAILABLE FOR THE SOUTHERN PLAINS. SIMILAR TO
WEDNESDAY...A DRYLINE TO OUR WEST (BUT LIKELY CLOSER) MAY AGAIN
FOCUS AFTERNOON CONVECTION THAT COULD APPROACH SATURDAY EVENING.
WITH A VIGOROUS 40- TO 50-KT LLJ SATURDAY NIGHT...AFTERNOON
CONVECTION FROM AS FAR NORTH AS KANSAS MAY BE ABLE TO CONGEAL INTO
A NOCTURNAL MCS THAT COULD FIND ITS WAY INTO NORTH TEXAS SUNDAY
MORNING. ANOTHER LOBE OF ENERGY ASSOCIATED WITH THIS STORM SYSTEM
COULD IMPACT NORTH TEXAS ON MONDAY.
THE MAIN UPPER LOW WILL THEN MEANDER TOWARD THE OHIO VALLEY NEXT
WEEK...AND EXTENDED GUIDANCE IS SUGGESTING IT COULD BECOME A CUT-
OFF. THE 12Z GFS HAS REDUCED THE AMPLITUDE OF BOTH THE BLOCKING
HIGH IN THE NORTH ATLANTIC AND THE LONGWAVE RIDGE ACROSS THE
WESTERN CONUS (AS COMPARED TO THE 06Z SOLUTION)...BUT THE CUT-OFF
REMAINS. ALTHOUGH THE ECMWF HAS SIGNIFICANT DIFFERENCES...IT TOO
HAS FULL-LATITUDE NORTHERLY FLOW THROUGH THE CENTRAL PLAINS. THIS
IS NOT GOOD NEWS FOR DROUGHT-STRICKEN TEXAS AS THIS WILL SHUT-OFF
THE TYPICAL SPRING STORM MECHANISMS. CPC 6-10DAY AND 8-14DAY
OUTLOOKS (ENCOMPASSING APR 28 - MAY 6) SHOW AN ENHANCED LIKELIHOOD
OF BELOW NORMAL TEMPERATURES AND BELOW PRECIPITATION FOR NORTH AND
CENTRAL TEXAS.
I saw that CPC outlook today. I noticed the below normal temps and below normal precip, which I thought was odd.
What I have been seeing on some forums around the web in the last few hours is that if the latest Euro verified and the storm moves a bit slower, than we could be in very big trouble on Sunday. But if the 18z GFS verified, Saturday would be a very bad day for Kansas and Oklahoma but may or may not be as bad here on Sunday.
