Scientific Forecaster Discussion
fxus64 klch 282349
Area forecast discussion
National Weather Service Lake Charles la
649 PM CDT Tue Mar 28 2017
pressure gradient remains tight across the region as the new
developing surface low and frontal system becomes established
along the east slopes of The Rockies this eve. This system will
move eastward with the sfc low projected to lift to the NE.
Looking for the winds to remain up over night W/ clds returning
twrds midnight and slowly falling. No problems to vsby W/ storm
actvty by the late aftn/eve timeframe. Thru midnight the problem
of the day will be winds...aftr midnight low ceilings W/ winds
continuing to be a flight issue. VFR becmg IFR aftr midnight.
Previous discussion... /issued 414 PM CDT Tue Mar 28 2017/
the afternoon has been spent monitoring 30 second visible
satellite images of the very strong storms developing over central
Texas at this hour. The same system will be the one that brings
the potential for severe weather to our area tomorrow afternoon
and evening. Guidance is still indicating quite favorable
conditions for the development of severe storms Wednesday evening
with forecast cape values in the 2000 to 2500 j/kg range and 0-1
km shear 25-30 knots. There will be a bit of a cap to overcome
Wednesday, but the NAM and GFS have it washing out by late
afternoon. It's been some time since we've seen conditions look
this favorable and consistent in the forecast guidance.
Between then and now, winds will remain on the breezy side
courtesy of the tightening pressure gradient between the low over
Texas and high pressure off the East Coast of Florida.
The front will push through the area Thursday morning bringing the
threat for severe weather to an end from west to east and ushering
in some drier, if not much cooler, air. Upper level ridging
building in behind the front will yield mostly clear skies and
pleasant conditons Friday and Saturday.
The GFS and Euro are in better agreement this afternoon with
regards to the timing of the late weekend system with storms
beginning early Sunday and clearing the region early Monday. The
Canadian is now the outlier keeping the upper low much further
south and lingering over the area into Tuesday. Therefore, more
credence is lent to the GFS/Euro solution with regards to timing.
However, there remains dramatic differences with regards to quantitative precipitation forecast
totals between the two with the GFS still much higher (five to
seven inches) than the Euro (one to two inches). Think there is
something to be said for the GFS having come down four to five
inches in the last 24 hours. That said, wpc has indicated that at
least some weight should be given to the GFS solution and higher
rainfall totals that could lead to a flash flooding situation
somewhere along the Gulf Coast early next week. Still plenty of
time to monitor this.
the Small Craft Advisory has been extended until Wednesday night
as strong onshore winds associated with an approaching low
pressure area will keep winds in the 20-25 knot range and seas
five to seven feet. Small craft exercise caution has been added to
the coastal lakes and bays for gusty winds and Rough Lake waters
through the same time period. Thunderstorms are expected to
develop Wednesday evening through Thursday morning. Some of these
storms could become severe. The cold front will push through the
coastal waters from west to east Thursday morning turning winds
Preliminary point temps/pops...
aex 67 81 68 76 / 10 30 80 60
lch 67 81 68 78 / 10 40 80 50
lft 71 84 73 81 / 10 10 60 80
bpt 69 81 68 79 / 10 70 70 40
GM...Small Craft Advisory until 10 PM CDT Wednesday for gmz450-452-
Small craft exercise caution until 7 PM CDT this evening for
Small craft exercise caution through Wednesday evening for