Lexington Weather

Lexington, Massachusetts, USA

63°F

5/20/2024 6:55pm

Lexington Conditions: Clear
Temperature: 62.8°F / 17.1°C
Dew Point: 55.8°F
Relative Humidity: 78%
Wind: Calm, 10-min avg: Calm, gust: 2 mph
Barometer: 29.95 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for North Platte, NE

        
000
FXUS63 KLBF 200916
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
416 AM CDT Mon May 20 2024

.KEY MESSAGES...

* A slight risk of severe weather is possible on this evening 
  (Monday evening) with large hail up to baseball size, severe winds 
  up to 75 mph, and heavy rainfall up to 2 inches as the primary 
  threats.

* Active weather continues through mid-week, although, severe 
  potential remains low at this time.

* Cooler temperatures return on Tuesday with highs in the mid
  50s to low 60s before gradually warming through the end of the
  week (into the 70s by the weekend). 

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 414 AM CDT Mon May 20 2024

The main weather story in the short term will be the potential for 
severe thunderstorms this evening and into the overnight. Dewpoints 
will increase across the region by late this morning and into the 
afternoon as low level moisture advection intensifies. Moderate 
instability will also develop across southwest and south central 
Nebraska by the late afternoon. Ample instability will exist across 
the region to support the development of supercells across the 
Panhandle and into northeast Colorado. These storms will track 
eastward into southwest and south central Nebraska by early evening. 
Current model guidance suggests lapse rates above 7 C/km and shear 
above 50 knots. This combined with significant CAPE (over 1500 
J/kg), not to mention large CAPE in the -10 to -30 C layer, will be 
enough to support very large hail (potentially up to baseball sized) 
with these supercells. This environment will also create the 
potential for significant wind gusts up to 75 mph. 

The initial round of storms, the supercells, will have the greatest 
potential to have the large hail and strong winds. As these storms 
move eastward, another round of storms are expected to develop 
behind them, which are not expected to be as intense as the 
environment becomes worked over. However, these showers and 
thunderstorms could still produce hail up to 1 inch and wind gusts 
up to 60 mph for a few hours (through late evening). Eventually, 
storms will weaken and congeal into a MCS for the remainder of the 
overnight hours. This round will have the greatest potential to have 
heavy rainfall with may result in localized flooding. At this time, 
up to 2 inches of QPF are expected across southwest Nebraska and 
into north central Nebraska. Have decided not to issue any flood 
headlines at this time as this total rainfall will occur over 24 to 
30 hour timeframe. Although, some flash flooding of low lying areas 
or small streams is not entirely out of the question especially if a 
heavier shower drops a half inch or more in a short period of time. 
Will continue to monitor this as the event evolves tonight. 

Heading into Tuesday, rain showers and embedded thunderstorms 
continue throughout the day, although there are expected to be some 
breaks. The severe risk is low for Tuesday as a cooler airmass 
pushes in behind the departing front and the environment 
remains well mixed. Still, we'll have to be cognizant of the 
flooding potential heading into Tuesday afternoon especially 
across areas that have already seen heavy rainfall Monday night 
and early Tuesday. 

Regarding temperatures, highs will drop from the low 60s to low 70s 
today into the mid 50s to low 60s on Tuesday. This will be nearly 10 
degrees below normal for Tuesday (normals in the low to mid
70s). 

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 414 AM CDT Mon May 20 2024

A series of disturbances will continue to impact Nebraska through 
the weekend.  At this time, severe weather risk remains uncertain 
with confidence remaining low on timing, track, and locations. 
However, based on the latest guidance, best chance to see convection 
will be in the late afternoon and early evening as diurnal heating 
and instability is greatest. Will continue to monitor these systems 
as the week progresses and those with outside plans in the evening 
should stay weather aware and be prepared to make alternate plans. 

For temperatures, cooler temperatures from Tuesday will give way to 
a slow rise in temperatures into the weekend. Current model runs 
indicate 850 mb temperatures to rise back into the 10 to 16 degree C 
range by the weekend. While this will not equate to exceptionally 
warm surface highs, especially with showers and thunderstorms each 
day, highs will rise back to near normal in the mid 70s by the 
weekend. Low temperatures also return from the low 40s on Tuesday 
night into the low 50s by Saturday night which is just slightly 
above normals for this time of year. 

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 101 AM CDT Mon May 20 2024

VFR conditions are likely through the bulk of the valid forecast
period. Main aviation concerns will focus on transient, shallow
fog early in the period followed by gusty winds during the 
daytime and then the threat for rain and thunderstorms late.

Shallow fog has floated around the LBF terminal. Forecast
soundings show very shallow moisture near the surface but this
is expected to shift east closer to sunrise as winds increase
out of the north. Winds will gradually veer to easterly during
the daytime with gusts increasing to 25 to 30 knots as they do.
Eventually rain and thunderstorms will move in from the west.
Timing of this is medium confidence at this time with 1-2 hour
difference in various short-term guidance at this time. For now,
will hedge towards the mean value with adjustments possible
later. Convection will likely contain gusty erratic winds and at
least MVFR visibility reductions. Further degraded conditions
are possible but will hold off on including at this time.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...Kulik
LONG TERM...Kulik
AVIATION...NMJ