Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus64 kjan 270527 aac 
afdjan

Area forecast discussion...updated
National Weather Service Jackson MS
1227 am CDT Sat may 27 2017

Update...
updated for 06z aviation discussion

&&

Aviation...
06z taf discussion:
low stratus will spread across much of the area overnight,
bringing MVFR to IFR conditions at most taf sites (greatest
potential for IFR in the south part of the area, including
hbg/pib). The stratus deck will lift/break up through the morning
Saturday, with VFR conditions expected areawide through the
remainder of the taf period. S/SW winds on Saturday may be gusty
at times during the day. /Dl/

&&

Discussion...

No changes have been made for the forecast this evening, clouds
will continue to surround the County Warning Area as the night progresses (from
west to east). A warm night is in store as lows will linger
around 70 degrees. /12/

Prior discussion below:

Tonight through Saturday...

Latest satellite imagery showed a general west southwest zonal
pattern the the mid to upper levels and southwest flow in the low
levels. Low level moisture was slowly increasing across the region
from the southwest as dewpoints had increased into the upper 60s
across the MS river. A front with low pressure was observed across
the Southern Plains which brought a tight pressure gradient for some
breezy conditions across the Delta Region. Winds have gusted to
around 30 mph in the northwest Delta Region. Mid afternoon temps
were in the upper 80s to around 90 degrees.

For tonight winds will taper off to a light breeze as low level
moisture brings in clouds as well as mid 60s to lower 70s dewpoints
from the west. This will create a milder night with lows in the
middle 60s to lower 70s.

For Saturday the pressure gradient will tightened up as we get some
breezy conditions across the Delta. Don't expect the winds will gust
up to 25 mph. Expect the clouds to mix out by the early afternoon.
With the extra low level moisture and anomalous low level temps
expect highs to be from the upper 80s to the lower 90s. This will
especially affect areas generally along and west of the Mississippi
River where heat indices will be from 100 to approaching 105
degrees./17/

Saturday night through next week...

There will be a warm, muggy start to Saturday night as moisture
continues to pool south of an approaching cold front. A deep
upper trough associated with a closed low over Canada will
continue to trek across the plains Saturday night. Storms will
begin to fire along the surface front associated with this storm
system, eventually evolving into a mesoscale convective system somewhere near the
Missouri Valley. A very unstable to extremely unstable environment
will exist ahead of this front as it continues to move southeast
stretching from the Great Lakes to south Texas. Several mcs's
could develop along this front, eventually racing ahead of it
through the mid- south and eventually approaching the northern
reaches of the arklamiss by Sunday morning. However, capping
should prevent widespread strong storms through most of the
arklamiss during the day on Sunday. Sunday will be warm and humid
for most locations.

Storm chances will increase again for the arklamiss later on
Sunday evening through Monday morning as the front finally begins
to push through the region, supplying enough lift to break the
cap. Although instability will wane slightly overnight on Sunday,
the prefrontal airmass looks to be unstable enough with SBCAPE
values in excess of 2500 j/kg and 0-6 km lapse rates greater than
6.5 c/km to support isolated strong to severe storms throughout
the region from Sunday evening through Monday morning. The best
chances of severe storms will be late Sunday evening into Sunday
night in the northwest portions of the arklamiss where the front will
reach before there's a significant decrease in instability.

The front will stall over the region on Memorial Day, keeping rain
and storm chances with US throughout the day. Increased cloud
cover should keep significant instability at Bay, however can't
rule out an isolated strong to severe storm in locations where
some clearing could lead to increased instability.

The main threat with storms from Sunday morning through Monday
will be large hail and damaging straight line winds. The frontal
boundary will have weakened significantly by Tuesday, however
diurnal type thunderstorms will be possible each day through next
week, continuing the active period of weather.

&&

Preliminary point temps/pops...
Jackson 73 89 70 82 / 11 26 67 62
Meridian 72 89 70 83 / 10 24 52 64
Vicksburg 73 89 71 81 / 15 27 68 62
Hattiesburg 72 89 72 83 / 10 23 32 71
Natchez 74 88 71 81 / 11 29 53 68
Greenville 73 86 69 81 / 29 55 70 42
Greenwood 72 86 69 81 / 23 50 69 46

&&

Jan watches/warnings/advisories...
MS...none.
La...none.
Arkansas...none.

&&

National Weather Service Glossary of Abbreviations