Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 250451

Area Forecast Discussion
National Weather Service Lake Charles LA
1151 PM CDT Mon Jul 24 2017

Actvty has died off this eve although the CI conts. Looking for
additional mid lvl clouds thru the ovrnght hrs otherwise VFR
flight rules to cont thru sr.


.PREV DISCUSSION... /issued 716 PM CDT Mon Jul 24 2017/

Isolated showers cont to dvlp ovr se Tx and sw La this eve. This
will cont thru the eve hrs before diminishing with all sites xpcd
to rmn VFR.

PREV DISCUSSION... /issued 351 PM CDT Mon Jul 24 2017/

A mid level weakness and shear axis is noted from Mississippi
across Louisiana into east Texas. Along the weakness, a meso vort
max is seen rotating east of the Sabine River over central
Louisiana just north of the forecast area. This helped enhance
the earlier convection that brought some heavy rainfall this
morning to Vernon Parish, with the KPOE ASOS recording around 2.5
inches of rainfall, with radar estimates showing 3 to 4.5 inches
of rainfall west of the ASOS location across western and southwest
Vernon parish. Most of the activity has since diminished with just
isolated showers remaining.


The mid level weakness and shear axis will gradually dissipate
over the next day, as mid level ridging and drier air begins to
move in. Will keep small rain chances in for tonight and early
Tuesday to account for nocturnal development near where the meso
vort max center will be located, and across the northeast
portions of the forecast area.

Otherwise, mid level ridging bringing in drier air in the mid
levels will be the main weather player for the remainder of the
week. Precipitable water values will drop to mainly below 1.5
inches with Mean RH from the the surface to 50H less than 50
percent. This will greatly reduce rain chances to less than 20
percent, and will not mention any showers or storms for the
Wednesday through Friday period. With less convection, air
temperatures will be a couple of degrees warmer, and with a south
wind at the surface, moisture values in the low levels will stay
up bringing muggy conditions. Expect afternoon max heat index
readings for Thursday and Friday to be projected at 105F to 107F
degrees and just below heat advisory criteria.

Over the weekend, an upper level ridge will strengthen and be
centered over the southwest US. In return, an upper level trough
will dig down the east coast. This will result in a deeper
northerly flow across the forecast area, and what the progs are
showing, a backdoor surface front to move through the forecast
area. Still some differences between the GFS (faster with frontal
passage on Saturday) and the ECMWF (slower with frontal passage on
Sunday) to the timing of this boundary. Still some lower than
normal confidence for the weekend forecast as it is unusual to
have a frontal boundary make it through the forecast area in late
July. At this time will lean toward the slower solution.
Therefore, will see an increase in showers and thunderstorms over
the weekend, ahead of the boundary. If frontal passage verifies,
then some drier air for early next week, with a little less
daytime humidity and lower night time low temperatures.


A weak surface high is located over the north central Gulf of
Mexico this afternoon. This surface high will continue to ridge
across the northern Gulf into the coastal waters that will allow a
general weak pressure pattern with light onshore winds and
relatively low seas. In the meantime, an upper level ridge will
build over the coastal waters helping to reduce chances for
showers or thunderstorms.



AEX  75  92  73  95 /  20  20  10  10
LCH  77  92  75  93 /  10  10  10  10
LFT  75  92  73  93 /  10  10  10  10
BPT  77  92  76  94 /  10  10  10  10




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