Area forecast discussion...updated
National Weather Service Memphis Tennessee
1225 PM CDT sun may 19 2013
Update...
Updated to include 18z aviation discussion below.
Jcl
&&
Discussion... /issued 1005 am CDT sun may 19 2013/
Skies are partly to mostly sunny across the forecast area this
morning with temperatures ranging from the middle 70s to lower 80s. A
few showers moved across portions of northwest Tennessee earlier
this morning but this activity has moved into middle Tennessee.
The remainder of the day should be dry with temperatures
approaching 90 degrees in some areas. Will update forecast to
remove mention of probability of precipitation for today.
Ars
Previous discussion... /issued 432 am CDT sun may 19 2013/
An upper level ridge of high pressure will continue to build into
the middle south today. Residual troughing over eastern sections of
the middle south this morning may continue to support isolated
showers and thunderstorms this morning across west Tennessee and
far northeast Mississippi in the vicinity of the Tennessee River.
This activity should diminish later this morning as the upper
ridging builds east and suppresses convection. Morning cloud cover
will likely give way to mostly sunny skies this afternoon.
Temperatures should rise into the upper 80s to around 90 degrees
along with continued seasonably high dewpoints in the upper 60s to
around 70 degrees. This will result in afternoon heat index values
rising well into the 90s.
The upper ridge will continue to move east over the next few days
but should keep mainly dry weather in place over the middle south along
with very warm and humid conditions through Monday.
A potent upper level low pressure system currently over the
central rockies will lift slowly northeast into the northern
plains through early next week. A series of shortwave disturbances
will swing around the southern periphery of the upper low. The
first in a series of shortwaves will lift northeast across the
Southern Plains into the middle Mississippi Valley later today
into tonight. This will result in showers and thunderstorms
developing over the central and Southern Plains which will lift
into the middle Mississippi Valley tonight. This activity is
expected to remain north and west of the forecast area through
Monday. A second shortwave will likely follow a similar trajectory
late Monday and Monday night. Thunderstorms will again develop
over the Southern Plains Monday afternoon and evening...lifting
northeast towards the middle Mississippi Valley Monday night. Far
northwest portions of the middle south may be grazed by the activity
late Monday night before lifting to the north. Plan to carry
chance probability of precipitation over portions of northeast Arkansas and the Missouri
bootheel after midnight Monday into early Tuesday morning.
A third and stronger shortwave is expected to eject from the
Southern Plains and across the middle south Tuesday night into
Wednesday. Latest model guidance suggests that this shortwave will
take on an increasingly negative tilt as it moves into the
forecast area. Instability and shear should strengthen in advance
of this feature as the shortwave overspreads a warm and humid
airmass in place over the region. This should result in the
development of numerous showers and thunderstorms over western
areas by Tuesday evening that should spread northeastward across
the remainder of the forecast area through Wednesday. The degree
of shear and instability expected appears favorable to support the
potential for severe thunderstorms. It still remains too early to
provide specific details on eventual threats and magnitude of the
severe event. Stay tuned to the latest forecast over the next
couple of days as this potential severe weather event unfolds.
The shortwave should lift northeast of the forecast area Wednesday
night leaving broad troughing in place over the region into
Thursday as the upper low to the north moves east into the Great
Lakes region and attemps to phase with shortwave energy dropping
south through eastern Canada. Warm and humid conditions should
persist into Thursday with scattered showers and thunderstorms
continuing across the area. The phasing systems over the northeast
U.S. Should help to carve out a deeper upper trough over the
eastern Seaboard Friday into next weekend. This should help to
force a cold front across the middle south on Friday with high
pressure building south. This should allow for a return to dry
weather by next weekend along with slightly cooler and less humid
conditions.
Jlh
&&
Aviation...
18z taf cycle (19/18z-20/18z)
MVFR ceilings will occur at ktup until 19z...otherwise VFR
conditions will occur at the taf sites this afternoon and
tonight. MVFR ceilings spreading into the area from the south and
southwest after 20/12z. Winds this afternoon at kmem...kjbr...and
kmkl south 10-15 kts with gusts 18-22 kts...winds at ktup S 10 kts.
Winds tonight south 6-12 kts tonight with the the strongest winds
at kmem and kjbr. After 20/12z S-SW winds 10-15 kts...with gusts
to 22 kts at kjbr.
Jcl
&&
Preliminary point temps/pops...
mem 73 90 72 89 / 10 10 10 30
mkl 69 89 70 89 / 10 10 10 20
jbr 71 88 70 86 / 10 10 20 50
tup 69 89 68 90 / 10 0 10 10
&&
Meg watches/warnings/advisories...
Arkansas...none.
MO...none.
MS...none.
Tennessee...none.
&&
$$
