Area Forecast Discussion Issued by NWS Jackson, KY
000
FXUS63 KJKL 081315 AAA
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
915 AM EDT Thu Jun 8 2023
.UPDATE...
Issued at 915 AM EDT THU JUN 8 2023
Now that dense fog has begun to dissipate and lift around the
area, the dense fog advisory has been cancelled. Removed mention
of fog from both the hazardous weather outlook and zone forecast
text products and sent out updated versions of both of those. The
updated grids have been saved, published, and sent to NDFD and
remote web farms.
UPDATE Issued at 748 AM EDT THU JUN 8 2023
Hourly grids have been updated based on recent observations. The
fog has begun to lift in some locations, especially the northern
edge of the dense fog advisory. This fog should lift further over
the next hour and at this point have opted to let the dense fog
advisory run its course.
&&
.SHORT TERM...(Today through Friday)
Issued at 416 AM EDT THU JUN 8 2023
Early this morning, an upper level low was centered over the
northeast Conus with an associated trough extending south and
southwest into the OH Valley and Appalachians to the southeast. A
shortwave trough moving through this trough was moving across the
OH Valley region at this time. Meanwhile, an area of upper level
ridging extending north from Mexico into the Southern Rockies
with another upper level ridge extending from the Central to
Northern Plains and then west along the US/Canadian border.
Further west, an upper level low was moving across the desert
Southwest. At the sfc, a ridge of high pressure was centered over
the Lake vicinity of Lake Huron and extending into the mid MS and
OH Valley regions. Meanwhile, the frontal zone that brought
precipitation to the area over the past 36 hours had dropped well
south of the area and extended from the Atlantic across the Gulf
states, before turning northwest and be coming nearly stationary
to the Ozarks and then north over parts of the central and
northern Plains to Manitoba. Despite the shortwave trough
approaching the area at present, most of the area has experienced
substantial clearing following the rainfall over the past 24 to 36
hours. Drier air has been slower to advect south of the I 64
corridor and especially so from near the Mountain Parkway south.
This has led to widespread dense fog over much of the are south of
I 64. However, where more substantial moisture remains over
Harlan and Bell counties, the approaching shortwave has led to a
few showers dropping south and southeast. Temperatures had dropped
into the upper 40s in the valleys of the far north with generally
50s to around 60 elsewhere.
The shortwave trough axis will move southeast of the area around
dawn on Thursday as it rotates around the meandering upper level
low that will remain over the northeast through the short term
period. over the northeast. The axis of upper level ridging
extending from Mexico into Southern Rockies to Plains initially
should shift into the Southern Plains through the end of the
period and extend into MT at that time. At the sfc, the center of
the ridge of high pressure is expected to move south to the mid MS
to Lower OH Valley through the period and weaken as it does so.
RAP near surface smoke guidance suggests that haze from the
Canadian wildfires currently more concentrated north of the OH
River to the Northeast and mid Atlantic may arrive into eastern KY
behind the shortwave this morning to early afternoon as it moves
around the upper level low and work across the area into the day
on Friday although becoming less concentrated from northwest to
southeast as the upper level flow becomes more northwest on
Friday.
As for sensible weather today, the fog should lift and begin to
dissipate through around 3 hours after sunrise or near 9 AM EDT,
although it may linger as late as 10 AM EDT in some locations. The
dense fog advisory remains in effect through 9 AM EDT for all but
the 5 northernmost counties. As drier air moves in from the
north, some of the dense fog may erode from the north prior to
that time in areas north of the Mtn Pkwy. Otherwise, mostly sunny
skies are expected once the fog dissipates today with warmer highs
compared to Wednesday, but still below normal temperatures for
early June. Although there is some uncertainty, smoke from
Canadian wildfires may lead to an increase in haze from north to
south as the day progresses. The drier air will continue to advect
into the area today and this will set the stage for rather cool
low temperatures tonight, especially in the valleys along with a
ridge/valley temperature split. Some haze should remain tonight,
and less extensive valley fog development is probable. Any valley
fog should lift and dissipate early on Friday, with some haze
remaining. However, this may shift to the southeast as upper level
winds become more northwest during the day on Friday.
Temperatures will remain below normal on Friday, but highs will
continue to moderate closer to normal.
.LONG TERM...(Friday night through Wednesday)
Issued at 335 AM EDT THU JUN 8 2023
High pressure building into the region will favor a warm-up as
temperatures are forecast to climb into the mid-80s for Sunday.
However, through the day Sunday, an approaching shortwave and
associated surface low will gradually begin to impact the
Commonwealth. Models continue to remain in agreement with a
shortwave diving out of the northern Great Lakes into the Ohio
Valley. While this is occurring, the associated cold front will
cross through the Commonwealth. Deterministic models have continue
to slow this progression to a later Sunday event and therefore,
opted to do the same and slow down the FROPA a few hours compared to
the NBM. Showers and storms are expected to occur throughout the
day, mainly toward afternoon. Depending on the amount of cloud cover
will determine the overall strength of the front. Presently not
expecting widespread severe weather but a stronger storm can`t be
ruled out either. Once FROPA occurs Monday morning, high pressure is
forecast to build into the region. Models are in disagreement to how
the forecast is going to look going into the next; therefore, opted
to keep what the NBM had.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 755 AM EDT THU JUN 8 2023
Fog has begun to lift and even dissipate in some more northern
locations, and is no longer dense at KJKL and KLOZ at issuance
time. Otherwise, dense fog or even IFR to below airport min
ceilings lingered in most of the south and southeast including
KSME and KSJS and points south from there. KSYM has not been
affected by fog. Improvements in vis and ceilings back to VFR are
anticipated by the 13Z to 14Z period. Some valley fog may again
form toward 6Z and after, but should not affect the TAF sites.
Winds will be light and variable, before becoming northwest to
north around 14Z, and then returning to light and variable by 3Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...JP
LONG TERM...VORST
AVIATION...JP