Area forecast discussion
National Weather Service Jackson MS
415 am CDT Thursday may 23 2013
Short term...today through Friday night...
the primary concerns will be the risk of a few strong storms for
the later half of this afternoon into this evening across the west
half of the region. Also the risk of areas of dense fog across the
region for this morning. This followed by probability of precipitation and temperatures.
Latest satellite imagery showed the region under northwest flow
aloft with the base of an upper trough over the midsouth region.
A front was approaching the region from northern Arkansas. Surface
high pressure was noted across the region. Light winds and a low level
moist boundary layer with mostly clear skies had help areas of occasionally
dense fog to form across the region. Visibilities have been bouncing
up and down.
For today and tonight...with areas of fog around. Will put areas of
occasionally dense fog across the entire forecast area as
visibilities bounce up and down. Also of concern there will be
enough instability(ml convective available potential energy >3000 j/kg, lapse rate around 7c,
lingering frontal boundary coming into the region, increasing
moisture convergence for a few strong storms to develop for this
afternoon and evening. The WRF models especially the Storm Prediction Center WRF shows a few
strong storms coming out of southern Arkansas and Louisiana toward
the region by middle afternoon. Area soundings look a little dry especially up
in the middle levels with a cap in place...but the frontal boundary may
be the focus mechanism to get a few storms going. Will mention in
severe weather potential statement both fog potential and strong storms. The intensity of the few
strong storms should decrease during the evening hours. The Storm Prediction Center WRF
keeps the convection going after midnight and pushes it across the
east half of the region. Highs today will be middle to upper 80s. Lows
will be from the upper 50s to the middle 60s...which is around
normal for this time of year. Went close to mav guidance. As for
probability of precipitation put in low probability of precipitation for today with the Storm Prediction Center WRF in mind. Model probability of precipitation
were rather dry probably due to the somewhat dry soundings. Made
slight adjustments to mav probability of precipitation for tonight.
For Friday and Friday night...upper ridge axis over the plains will develop
toward the region. Cool surface high pressure moving from the upper
Mississippi Valley to the Great Lakes will provide dry weather to
the region. Highs on Friday will be from the middle 70s north to the
upper 80s south. Lows Friday night will range from the cool upper
40s east to the middle to upper 50s west...which will be well below
normal. Went close to mav guidance./17/
Long term...(saturday through thursday) high pressure will be in
control of regional weather Saturday. Ridging begins to give way
Saturday night with a shortwave moving through to flatten flow. The
Euro is advertising stronger forcing with this wave and brings an
area of moisture/precipitation across northern zones for Sunday. The higher probability of precipitation
called for by the Euro for Monday after the waves passes look a
little out of whack...weak isentropic flow notwithstanding...and the
more consistent dry forecast per the GFS will be followed for now.
Model solutions continue to differ in the farther periods of the
extended regarding placement of the upper Ridgeline and shortwaves
that push through but the general pattern will be low level southerly flow
in a region of weak upper forcing possible depending on where the
ridge/trough positions set up. In this type of regime the chance of
afternoon convection...even without significant forcing...will
gradually be on the increase due to persistent southerly flow that will be
in place. However models are also suggesting a potential for capping
due to the proximity of the upper ridge. Due to these uncertainties
the drier GFS will be followed for now.
&&
Aviation...currently we have areas of dense fog (ifr conditions)
across the region with visibilities bouncing up and down. Expect the
fog to lift by 14-15z. Also isolated strong storms will be possible
generally along and west of Interstate 55. Coverage will be minimal
as far as affecting taf sites. But if they do affect any one of the taf
sites glh gwo khks and kjan...could provide some brief gusty winds
of around 30-40 knots and some small hail through early this
evening. Winds will be variable at 5-7 knots./17/
&&
Preliminary point temps/pops...
Jackson 88 63 83 52 / 16 19 6 6
Meridian 89 61 85 47 / 12 17 7 5
Vicksburg 88 63 82 52 / 16 23 5 5
Hattiesburg 90 65 88 53 / 12 20 2 3
Natchez 87 65 84 56 / 16 23 5 6
Greenville 88 64 78 54 / 16 21 7 5
Greenwood 87 61 78 50 / 15 19 9 5
&&
Jan watches/warnings/advisories...
MS...none.
La...none.
Arkansas...none.
&&
$$
17/03
