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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Monday
• 
• High: 91 °
• Low: 70 °
• Chance of T-Storms

• Tuesday
• 
• High: 91 °
• Low: 64 °
• Chance of T-Storms

• Wednesday
• 
• High: 88 °
• Low: 68 °
• Partly Cloudy

• Thursday
• 
• High: 88 °
• Low: 72 °
• Partly Cloudy

• Friday
• 
• High: 90 °
• Low: 66 °
• Partly Cloudy

Area forecast discussion 
National Weather Service New Orleans la 
736 am CDT Monday may 21 2012 


Update... 
..sounding discussion... 


No problems with the flight this morning. In an attempt to not 
repeat myself for the fourth day in a row...the sounding continues 
to look very similar to previous days. The only difference is 
that today...with the weakening front nearing the area...a few 
showers and thunderstorms are not out of the question. If any 
stronger storms develop...some small hail is possible with wet 
bulb zero heights around 9500 feet and plenty of cape available 
for storms to work with. The inhibiting factor will be freezing 
heights above 13k feet which would aid in melting before hitting 
the surface and an overall lack of moisture with precipitable water values near 
1.1 inches. Winds are light and variable near the surface and out 
of the north and west aloft. 


98/so 


&& 


Previous discussion... /issued 354 am CDT Monday may 21 2012/ 


Synopsis... 
surface low pressure is centered north of Michigan with a cold 
front extending southward into central Arkansas and then westward 
through northern Texas. Surface ridge is centered over Iowa. 
Tropical Storm Alberto is located about 85 miles east of St. 
Augustine Florida...and not forecast to impact the local area. 


Locally...temperatures running generally in the upper 60s to lower 
70s under clear to partly cloudy skies. Patchy fog developing in 
some locations...but should clear up shortly after daybreak. 


Short term...today and Tuesday 


Upper trough will continue to move eastward today...forcing the 
weakening surface cold front toward the local area. While there 
will be little in the way of cooler or drier air associated with 
the front...it should provide enough forcing to fire isolated to 
scattered showers/thunderstorms across the region. Best chances of 
rain will be across the northern half of the area...nearer the 
front. 


Took a look at potential for severe weather...and while one or two 
strong/severe storms cannot be ruled out...widespread impacts are 
not expected. Instability near and ahead of the front will top 1000 
j/kg across much of the area during the late afternoon and evening 
hours. The front should also provide the necessary lift for 
convection. However...the limiting factor will be a lack of 
moisture with dewpoints forecast in the upper 50s to low 60s 
during much of the afternoon. Storm Prediction Center has included the local County Warning Area in a 
general thunder area...but any see text areas are far removed from 
the northern Gulf Coast. Given that the northwest flow regime can 
be over-achieving at times...will continue to mention possibility 
of one or two strong/severe storms in the severe weather potential statement...but confidence is 
not high for this scenario. 


Most convective activity will be limited to late this afternoon 
through tonight. However...with the weakening/stalling front 
lingering in the area Tuesday...will continue to carry a slight 
chance of showers and thunderstorms on Tuesday as well. 
Again...moisture will be limited...so severe weather is not 
expected. 


Long term...Wednesday through Sunday 
by Wednesday...the stalled frontal boundary is forecast to retreat 
northward as a weak warm front. High pressure then comes back with 
a vengeance. Deep layer ridging builds into the Tennessee Valley 
with a 590+ dam high at 500 mb. For the local area this means hot 
and humid conditions for the second half of the work week and into 
the weekend. Temperature forecast is a few degrees higher than 
guidance as it appears guidance is trending too close to 
climatology in the extended period. Will continue to carry 
afternoon temperatures in the low to middle 90s across the region during the 
extended period. Looks like a few places might even see the first 
triple digit heat index values of the season...but that will 
depend on how much moisture remains near the surface after daytime 
mixing brings down drier air from aloft. 


Concerning rain chances...the deep ridging will result in 
subsidence aloft which should curtail most if not all 
convection...so will continue to leave out any mention of rainfall 
while carrying only silent 10s for the pop. 


The ridge may begin to break down or shift eastward early next 
week as another upper level trough tries to muscle its way into 
the Upper Middle west. 


Aviation... 
VFR conditions will be the rule as a dry and stable airmass 
dominates the region. However...a weak inversion could allow for 
some MVFR visibility restrictions as visibilities fall to 4-5 miles 
at kmcb...khsa...and khum around 10-12z in the morning. A few 
thunderstorms will be possible this afternoon. Do not have mention 
of thunderstorms and rain in tafs yet b/c probability of precipitation are only around 20 percent but may have 
to update. Expect scattered/broken cumulus field to develop today. 


Marine... 
high pressure will hang on through Monday. A weak trough will 
move through the coastal waters on Tuesday and dissipate. High 
pressure will build over the coastal waters Wednesday and Thursday 
until it is absorbed by ridge over the entire southeastern US. 
Onshore flow will gradually increase from west to east through the 
weekend. 3 to maybe even 4 foot waves will develop in the outer 
waters. 


Decision support... 
dss code...blue. 
Deployed...none. 
Activation...none. 
Activities...isolated strong thunderstorms possible this 
afternoon. 


Decision support services (dss) code legend 
green = no weather impacts that require action 
blue = long fused watch/warning/advisory in effect or high 
visibility event 
yellow = heightened impacts with short fused 
watch/warning/advisory issuances; radar support 
Orange = high impacts - slight to moderate risk severe; nearby 
tropical events; hazmat or other large episodes 
red = full engagement for moderate to high risk severe and/or 
direct tropical threats; events of National significance 


&& 


Preliminary point temps/pops... 
mcb 89 62 87 61 / 30 20 20 10 
btr 91 66 90 68 / 20 20 20 10 
asd 90 64 89 64 / 20 20 20 10 
msy 90 71 89 71 / 20 20 20 10 
gpt 89 66 88 66 / 20 20 20 10 
pql 91 63 89 64 / 20 20 20 10 


&& 


Lix watches/warnings/advisories... 
la...none. 
GM...none. 
MS...none. 
GM...none. 
&& 


$$