Area forecast discussion
National Weather Service Jackson MS
340 am CDT Wednesday Jun 19 2013
Short term...the focus of the forecast will continue to revolve
around precipitation chances...especially for today and Thursday...but these
chances will overall less than what the area has seen the past
couple days. One of the key features that will influence our weather
is the stalled weak surface front across the area. This boundary has
become broad/diffuse...but is generally situated from tup to mlu.
While it would seem that areas along and south of said boundary
would have the best precipitation potential today...this not truly the
case. The reason is that some drier air in the middle levels is present
for areas just north of I-20. This is in part to northerly middle level
flow drawing southward that drier air as the shortwave passed across the
southern parts of the forecast area last evening. With all of
this...areas along and south of I-20 will have the deepest moisture
to work with today along with some low level focus from the stalled
surface boundary. Additionally...water vapor imagery shows the middle/upper
trough axis quite well and it is situated just to our west. This
feature should assist lift (esp this morning) and generate precipitation
across the southern half of the area. Thinking that the airmass has
been worked over quiet a bit...over all less storm coverage is
expected. Thus...following the 20-40% probability of precipitation from the GFS seem valid.
With another early start to activity...will trend probability of precipitation/weather down for
the late afternoon.
Like yesterday...temperatures will be held in check thanks to clouds and
the early start to precipitation. GFS guidance indicates this well and have
followed. Tonight will be generally quiet with clearings skies.
Temperatures will be a bit cooler than what we have see with upper 60s
expected.
Thursday will be a trickier forecast as the previous mentioned surface
boundary will still be in the general area but likely
situated/oriented in a different manner. Deep moisture will be
overall lower areawide with higher moisture content generally across
the SW/S half. What makes the forecast tricky is the presence of a
distinct shortwave dropping southeast. Associated with this feature will be
cooler temperatures in the middle level and aloft. The middle/upper level jet
will also be situated in a way that supports upward motion. Even as
these favorable features exist...model data is not showing much
development. I can't argue that there will be less overall
potential...but feel that enough ingredients will exist that
isolated storms will be possible during the afternoon. With
that...have increased probability of precipitation from 10% to 20% and mentioned slight
chance for afternoon activity. At this time...I will not mention any
possibility for strong storms...but this will have to be monitored
as the cooler temperatures aloft will lead to better lapse rates and a bit
higher instability as surface temperatures will be 2-4 degrees warmer. /Cme/
Long term...Friday through next Wednesday...an upper ridge will
try building into the western half of the forecast area Friday into
the weekend as an upper trough pulls off to the northeast and up the
East Coast. As this happens...the trough will leave behind a piece
of energy that'll set the stage for some isolated to scattered
afternoon and early evening showers and storms over mainly east and
southeast Mississippi through the weekend. Rain chances look to
wane heading into the new work week as the upper ridge builds
further east into the County Warning Area.
Otherwise...look for continued hot and humid conditions through the
forecast period. Guidance suggested highs and lows look reasonable
this morning. Highs each afternoon will range in the low to middle
90s...while lows each night generally range from the upper 60s to
lower 70s. /19/
&&
Aviation...some MVFR visible conditions are expected this morning with
some potential for IFR visible near glh. There is also some potential
for a brief period of IFR ceilings between 11-13z for sites along
I-20. There will also be some chance for rain showers/thunderstorms and rain today for the
southern half of the area and will mention that with vc wording.
Outside any convection...expecting VFR conditions to exist from
13-15z into tonight. MVFR visible will be possible tonight...mainly
after 07-08z. /Cme/
&&
Preliminary point temps/pops...
Jackson 89 68 91 69 / 41 12 17 6
Meridian 87 66 91 68 / 38 9 15 12
Vicksburg 88 67 91 68 / 36 12 17 4
Hattiesburg 87 69 92 69 / 46 25 23 12
Natchez 87 68 90 68 / 41 18 23 6
Greenville 90 68 94 70 / 6 3 7 3
Greenwood 90 67 93 68 / 6 3 5 5
&&
Jan watches/warnings/advisories...
MS...none.
La...none.
Arkansas...none.
&&
$$
Cme/19/
