245
FXUS61 KRNK 021758
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
158 PM EDT Sun Jun 2 2024

.SYNOPSIS...
A low pressure system in the Mid Mississippi Valley will track east
today bringing showers and thunderstorms to the region. Daily
showers and thunderstorms continue for the region through
Thursday, before drier weather returns for the end of the week.
After Sunday, temperatures will be near to slightly above normal
for much of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 145 PM EDT Sunday...

Key message:

   - Showers and isolated thunderstorms possible tonight and
     Monday

Short wave over the Tennessee Valley will move slowly across east
tonight. Low level winds will remain out of the southwest ahead of
this feature then turn to the west and northwest. Will keep
scattered showers in the forecast until  the short wave trough moves
through early Monday morning. The best coverage of precipitation
will be this afternoon between 19Z/3PM and 00Z/8PM. Challenging to
determine the probability of precipitation on Monday once the trough
passes.

Precipitable water values have climbed just above an inch and
surface dew points were in the mid 50s to lower 60s this afternoon.
Satellite images were showing a few breaks in the clouds. Locations
that get the most heating may have CAPES around 500 J/kg and enough
instability maintain isolated thunderstorms today and again Monday
afternoon. Will keep patchy fog in the forecast overnight with
the near surface air mass moist due to the rainfall today.

Mild dew points and cloud cover will hold minimum temperatures in
the 50s and 60s. Expecting more sunshine then today on Monday
afternoon and with a downslope component to the surface and low
level wind, the foothills and piedmont will warm into the lower 80s.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
As of 1205 PM EDT SUNDAY...

Key Points:

1. Temperatures will be above normal during this time period.
2. Precipitation chances will gradually increase through the period
with Wednesday night seeing the greatest coverage with the arrival
of a cold front.

A look at the 2 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows an upper ridge over the region Monday night. This
ridge holds fast for Tuesday, but with a shortwave trough moving
into the western Great Lakes region by Tuesday evening. For
Wednesday, the east coast ridge weakens with its axis shifting east.
The western Great Lakes shortwave trough pivots such that it becomes
negatively tilted with its axis reaching into parts of the Tennessee
Valley. At the surface for Monday night, low pressure is expected to
located over MT, with an associated cold front extending south along
the lee of the Rockies. A weak surface high will be over the mid-
Atlantic region. Tuesday into Wednesday, the high over the mid-
Atlantic region is expected to shift into the western Atlantic while
the low move east into central Ontario. By Wednesday evening, its
associated cold front will be around the Mississippi River Valley
region.

Output from the 2 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures around +16C across the area Tuesday through
Thursday. Precipitable water values are expected to gradually
increase through the Monday through Wednesday time period. On
Monday, values are expected to range from 1.00 to 1.25 inch, and
reach around 1.50 inch by Wednesday. This value will touch the low
end of the 90 to 97.5 percentile of the 30-year climatology.

The above weather scenario points towards increasing chances of
showers and storms in advance of an approaching cold front. On
Tuesday, this activity will be primarily during the peak heating of
the day and across the mountains. For Wednesday, coverage will
continue to increase in coverage and time of occurrence.

Late Wednesday night look for very good coverage across the area,
especially in the west, as a cold front crosses the area.

Temperatures across the region will average above normal for this
time of year.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 1205 PM EDT Sunday...

Key Points:

1. Temperatures will be a bit cooler Friday through the weekend.
2. Daily chances of at least showers and perhaps a thunderstorm
or two with coverage best over the mountains.

A look at the 2 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows for Thursday a negatively tilted shortwave trough
inching eastward, such that its trough reaches the southern
Appalachians. For Friday, not much movement is expected for the
trough, however it is expected to deepen, and almost cut off from
the northern flow across northern Canada. By Saturday, the trough is
expected to expand in scope, with its orientation not changing all
that much. However, its geographical range is expected to reach more
of that of a longwave trough. A similarly persistent ridge is
expected to be located over the Rockies. For Sunday, little change
is expected in the overall synoptic pattern across CONUS. At the
surface on Thursday, surface low pressure will be near James Bay
with its associated cold front crossing our region during the
morning. A reinforcing 850mb front will cross Thursday
evening/night. Friday through Sunday, the surface low is expected to
remain situated near the Ontario/Quebec border, with a ensemble
averaging keeping a lee side trough/front over eastern VA south into
SC.

Output from the 2 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures cooling a bit from mid-week, down to around
+12C to +14C by Friday. Values remain around +12C to +14C through
the weekend. Precipitable Water values are expected to gradually
trend lower heading into the weekend. Expected values on Thursday to
be in the 1.25 to 1.50 range. Friday through Sunday, values around
1.00 inch will be more common.

Look for a cooler period and one that will see daily chances of at
least showers, and perhaps a few thunderstorms, a general pattern of
upper level troughiness takes up residency over the area. However,
on average, coverage should be greatest over the mountains each day.
While coverage of the precipitation will not be continuous through
this entire time period, confidence in the timing of the periods of
greater coverage versus lesser coverage of precipitation is low at
this time.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
As of 145 PM EDT Sunday...

Short wave over the Tennessee Valley will move slowly across
east tonight. Low level winds will remain out of the southwest
ahead of this feature then turn to the west and northwest. Will
keep scattered showers in the forecast until the short wave
trough moves through early Monday morning. The best coverage of
precipitation will be this afternoon between 19Z/3PM and
00Z/8PM. Challenging to determine the probability of
precipitation on Monday once the trough passes.

Precipitable water values have climbed just above an inch and
surface dew points were in the mid 50s to lower 60s this afternoon.
Satellite images were showing a few breaks in the clouds. Locations
that get the most heating may have CAPES around 500 J/kg and enough
instability maintain isolated thunderstorms today and again Monday
afternoon. Will keep patchy MVFR to IFR fog in the forecast
overnight with the near surface air mass moist due to the
rainfall today.

Ceilings will continue to gradually lower this afternoon and
evening, eventually becoming IFR across much of the mountains
overnight, then improving back to VFR throughout the morning
Monday.

Average confidence for ceiling and wind.
Below average confidence for visibility and the location/timing
of any thunderstorms.


EXTENDED AVIATION OUTLOOK...

Mostly VFR, but ISOLD/SCTD SHRA/TSRA could result in periodic
restrictions through the period. Some BR is also possible,
especially in valley locations through Tuesday.

Greater likelihood of flight restrictions/MVFR (or lower)
on Wednesday and Thursday with showers and thunderstorms ahead
of a cold front.

Friday is expected to be drier and a better probability of VFR
conditions behind the front.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$

SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...DS
AVIATION...AMS