Weather

462 
fxus64 kshv 261959 
afdshv 


Area forecast discussion 
National Weather Service Shreveport la 
259 PM CDT Sat Jul 26 2008 


Discussion... 
isolated showers and thunderstorms just along the fringes of the 
County Warning Area this afternoon will continue to drift south and east along 
the eastern edges of the upper ridge. Will wait until press time 
to decide weather or not to mention any precipitation across our northern 
and eastern zones but leaning towards leaving out all mention at 
this time. 


Of greater importance this forecast cycle will be the oppressive 
heat across the region. Checking hourly heat index values... 
currently readings are just below our 105 degree criteria. Short 
term forecasts advertise 850mb temperatures rising some two to three degrees 
on Sunday and holding there through at least Tuesday of next week 
depending on your model of choice. Combine this with increasing 
1000-850mb thickness values...especially along and north of the 
I-20 corridor suggests that heat advisory criteria will be met. 
Further south...while ambient temperatures may not be as warm as 
those expected across the north...higher dewpoint temperatures 
suggest that criteria again will come close to our threshold. The 
only fly in the ointment so to say with whether to issue the 
advisory or not is that afternoon dewpoints should mix down...at 
least across our northwest zones the next couple of days. But 
given the fact that the ambient temperature will likely be higher 
across these areas...again...our criteria being met will be close 
enough for US to go ahead and Post a heat advisory for all 
areas...making it valid from noon on Sunday through 00z Tuesday. 
Advisory may have to be extended for at least portions of the 
region beyond Monday but at this time...will keep the product 
fresh for only two days out in the forecast and will let future 
forecasters make the decision of extension or not. 


Over the long term...followed mex guidance closely concerning 
temperatures across the region beyond Wednesday of next week but 
if the European model (ecmwf) is to be believed...oppressive heat may continue 
into the end of next week as 850mb temperatures remain high enough such 
that if this solution is close to reality...we will be dealing 
with triple digit temperatures beyond Tuesday. 


Prelims to follow...13. 


&& 


Aviation... 
satellite imagery indicates that a field of scattered to broken stratocu is 
widespread across the four state region...and that showers are 
developing across north central Louisiana and south central 
Arkansas. Expect afternoon convection to remain east of the Red 
River for the most part...and be spotty in nature. The best chances 
for thunderstorm activity will be at mlu and eld...where brief 
reductions in visibility to around 1sm under heavy downpours...and 
gusty outflows as high as 30kt...are possible. Stratocu will fade 
away around sunset across the region when heating ends...reducing 
cloud cover to patches of cirrus mainly across the east. 


For Sunday morning...low level winds across East Texas may be 
sufficiently from the south to allow patchy stratus to affect 
lfk and tyr...with ceilings as low as 1kft. In any event...moisture 
advection is pretty weak...so expect any stratus that does develop 
to scatter by around 10z. /18/ 




&& 


Preliminary point temps/pops... 
shv 76 101 76 101 76 / 0 0 0 0 0 
mlu 76 101 76 101 74 / 20 20 20 0 0 
deq 72 101 72 101 72 / 0 0 0 0 0 
txk 76 102 76 102 76 / 0 0 0 0 0 
eld 75 101 74 101 74 / 20 20 20 0 0 
tyr 76 101 76 101 76 / 0 0 0 0 0 
ggg 76 100 75 101 75 / 0 0 0 0 0 
lfk 75 99 75 99 74 / 0 0 0 0 0 


&& 


Shv watches/warnings/advisories... 
Arkansas...heat advisory from 12 PM Sunday to 7 PM CDT Monday for the 
following zones: arz050-051-059>061-070>073. 


La...heat advisory from 12 PM Sunday to 7 PM CDT Monday for the 
following zones: laz001>006-010>014-017>022. 


OK...heat advisory from 12 PM Sunday to 7 PM CDT Monday for the 
following zones: okz077. 


Texas...heat advisory from 12 PM Sunday to 7 PM CDT Monday for the 
following zones: 
txz096-097-108>112-124>126-136>138-149>153-165>167. 


&& 


$$ 


13/18