Scientific Forecaster Discussion

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Area forecast discussion...updated 
National Weather Service Jackson MS
912 am CDT sun Apr 20 2014

Update...surface and upper level ridging remain in place over the
forecast area this morning...making for a beautiful Easter Sunday.
Clouds will remain scarce through the daytime hours...then begin to
increase over the western half of the area by this afternoon. The
current forecast is in good shape and no major adjustments will be
made. /Dl/


Aviation...expect VFR conditions for all sites through much of the
remainder of the period...but patchy fog will once again be possible
for taf sites early Monday morning. The winds will generally be out
of the east this afternoon at 7-10kts becoming light out of the
southeast overnight. The patchy fog will lift by 14z. /17/


Discussion... /issued at 415 am CDT sun Apr 20 2014/
short through Monday night...strong surface high
pressure ridging and upper ridging will continue to prevail across
the arklamiss today into tonight. A nice day is on tap with highs
ranging from the upper 70s to low 80s. The upper ridge will shift to
the east overnight giving way to upper troughing on Monday. A few
showers will be possible mainly west of the river by Monday morning.
Moisture will increase across the area on Monday with precipitable waters climbing
above 1.2 inches by Monday afternoon across much of the area. Expect
mainly isolated showers across most the area Monday afternoon as the
models indicate little instability through the day...but
thunderstorms will be possible mainly for the Delta areas as there
will be a little more instability and moisture to work with in those

By Monday evening into Monday night a cold front will move across
Arkansas and will extend just north of the Delta by Tuesday morning.
Moisture will be on the increase with precipitable waters approaching 1.5 inches
along with increased instability. As the boundary approaches expect
an increase in thunderstorm activity mainly for areas northwest of
the Natchez trace late Monday night into Tuesday morning. /15/

Long term...Tuesday into next weekend...positively-tilted upper
trough and associated lagging cool front will be pushing across the
region Tuesday into Tuesday previously advertised.
Moisture levels and overall lift and wind shear are quite marginal
by April standards...although there should be enough instability for
isolated to scattered thunderstorms of a rather unorganized nature.
Mav/mex probability of precipitation deemed a little low considering available output
consensus from other models was running higher. However...I still
failed to boost probability of precipitation to likely category in any areas and it looks
like any rainfall amounts on Tuesday greater than half an inch
should be very isolated (which is definitely good news). The severe weather potential statement for
this system will be kept clear.

Any lingering showers or storms Tuesday evening in southeastern MS
should be ending well before midnight with the mentioned frontal
boundary pushing down toward the coast late in the night. Models
depict dry air behind the boundary may have a hard time getting into
southern zones so for early Wednesday morning south of I-20 fog
might be an issue.

Temperatures late Tuesday night into Wednesday will be around
seasonal behind the cold front...but southerly flow quickly building
in by Wednesday night into Thursday will usher in a warming
trend...possibly lasting into next weekend. The one wildcard will be
a frontal system centered well to the north which could drag a front
into The Heart of the region around Friday. Model consensus has been
trending further north with this system and its southward frontal
progression before stall. With the latter in mind the potential for
considerable impact from this system is not very high at
present...even considering daytime instability late this week could
be running somewhat high due to increasing warmth and low level Gulf
moisture. The big inhibiting factor for significant storms in our
region in such a scenario would be thermal middle layer capping keeping
a lid on robust convective development in the absence of
considerable atmospheric lift (which should be to our north).

Models are also coming around to early next week being a time period
to watch in terms of truly active weather as copious Pacific jet
stream energy pours efficiently across the Continental U.S. From west to east.
Any associated disturbances in this potential flow regime eventually
coming across the lower MS valley should likely have some
instability to work with. /Bb/


Preliminary point temps/pops...
Jackson 80 54 81 59 / 0 9 19 18
Meridian 77 48 79 56 / 0 6 11 12
Vicksburg 80 55 79 59 / 0 14 20 30
Hattiesburg 79 52 80 59 / 0 4 12 11
Natchez 79 55 80 59 / 0 11 20 15
Greenville 81 57 80 61 / 0 15 29 49
Greenwood 81 55 80 61 / 0 9 27 43


Jan watches/warnings/advisories...