Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Jackson MS
451 am CDT Monday Jul 6 2015


Today through Tuesday has been a much quieter night than
previously across the arklamiss region. Current satellite and
analysis shows drier air moving south into the region which is
reflected by the middle 60 dewpoints being observed. This is about 1-3
degrees drier than this time yesterday morning. Surface analysis also
shows that the surface high pressure is residing over the region...and
likely having some control over our weather.

Today should be much drier air than the previous few days as the
upper trough that had been influencing our weather and storm
development over the weekend has pushed off to the east. While during
that time models(particularly the hi-res suite) had not been
depicting the expected weather scenario the best...they were a lot
wetter/more active than what is being shown for today. This lends
some confidence that coverage today should be a bit lower. In
fact...all hi-res guidance and the sseo indicate the best location
for any storm development would be across eastern Mississippi...
particularly across the Golden Triangle region. Therefore...have gone
with lower probability of precipitation than previously forecast but more confined to the
eastern/northeastern portion of the County Warning Area. This activity should wait
until afternoon to develop as current dry air should be replaced by a
bit moister air as depicted by an increase in Theta-E values and precipitable water
values(exceeding 1.5 inches by afternoon). In terms of severe
potential...while coverage should not be great today there does
remain some limited potential for a strong to severe storm given
vertical totals around 27-29c and cape nearing 3000 j/kg among other
parameters. Have kept the limited risk in the severe weather potential statement/graphics but will
shrink the area to better fit where storms may actually occur.
Outside of this area...there is a bit more of a conditional risk as
parameters still look good for a strong storm but confidence in
seeing any convection is lower.

After today rain chances start to decrease as the upper ridge begins
to build over the region. This will keep a stalled front and
associated rain north of the region. However...temperatures will
begin to get warmer. Highs both today and Tuesday will be in the 90s
with overnight lows in the 70s. /Jc/

Wednesday through Sunday...

Increasing heat and small rain chances will best describe the long
range forecast. Nwp guidance consensus is for the subtropical
ridge to expand westward and intensify over the arklamiss region as
we go from middle to late week and through the weekend. For
Wednesday...have stuck with the low guidance probability of precipitation given relative
lack of deep layer moisture (precipitable water near/less than 1.5
inches for much of the area)/ well-mixed relatively dry boundary
layer layer and anticyclonic flow which will limit moisture
convergence. With that said...middle level temperatures will be cool
for a solid ridge in middle July (h500 temperatures ~ -8 degree c) and combined
with increasing low level heat should result result in steep lapse storms that manage to develop would have a chance to
become strong/severe.

Moisture and convective coverage could increase slightly beyond
Wednesday...but expect the same general pattern to keep thunderstorm
coverage limited. With high temperatures starting to reach the middle looks like heat indices in the 100-105 f range will be more
common...especially over the Delta Region. The heat is expected to
peak this weekend and possibly persist into early next week. /Ec/


Aviation...a few sites are experiencing MVFR to IFR ceilings this
morning and reduced visibility thanks to some patchy fog and low
stratus. This will continue until about 15z after which conditions
should begin to improve. Some afternoon showers and storms will
again be possible mainly across east MS and possibly affecting
kgtr/kmei/khbg. Coverage should be much more isolated than has been
the case over the weekend. South to southwesterly winds will
continue around 5-10kts before subsiding tonight. /Jc/


Preliminary point temps/pops...
Jackson 91 72 92 73 / 18 13 8 8
Meridian 90 70 91 70 / 30 11 5 3
Vicksburg 91 72 92 73 / 10 10 7 8
Hattiesburg 93 73 92 73 / 19 9 6 10
Natchez 89 74 91 74 / 10 6 9 9
Greenville 90 74 92 74 / 18 12 3 8
Greenwood 88 70 90 73 / 19 8 6 6


Jan watches/warnings/advisories...



National Weather Service Glossary of Abbreviations