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Office: JKL

FXUS63 KJKL 202003
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
303 PM EST Tue Feb 20 2018

.SHORT TERM...(This evening through Wednesday night)
Issued at 303 PM EST TUE FEB 20 2018

Impressive height anomalies over eastern Kentucky has led to
record breaking high temperatures today. We have in fact set the
all time record high for Jackson for February, with London likely
to fall just a few degrees short. Gusty southwest winds continue
to crank across the area with wind gusts up to 35 mph still likely
occurring in our northern and western zones. Plan to let the lake
wind advisory continue through the evening hours. With clear
skies in place, we should see temperatures in the eastern valleys
drop quickly as they decouple. Skies could stay mostly clear
through a good chunk of the night, allowing lows in the eastern
valleys to dip well into the 50s. Our western areas could stay
fairly mixed tonight given the stronger gradient to the west. A
cold front will work east across the Ohio river valley tonight
into Wednesday and Wednesday night. Showers will be ongoing along
the front throughout the period. As the front pushes east and
southeast, the forcing along the front will be weak through
Wednesday. However, enough convergence should be present to allow
for good rain chances for most of the area. A shortwave riding
northeast across the region may provide an uptick along the front
late Wednesday night. While there will be instability developing
Wednesday afternoon, model guidance is suggesting the better
thunder chances may be Wednesday night with the shortwave
providing some added lift. Models are likely overplaying dewpoints
on Wednesday, accounting for the surface instability. Rain
amounts through Wednesday night should remain under an inch and
fairly spread out. Thus, no plans for any flood watches for our
area.

.LONG TERM...(Thursday through Tuesday)
Issued at 303 PM EST TUE FEB 20 2018

Long term discussion will follow shortly.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1213 PM EST TUE FEB 20 2018

Gusty southerly winds will continue through early this evening and
will be the main aviation concern. These winds will subside this
evening as surface becomes decoupled. Conditions will remain
mostly VFR through the period, although some mid level clouds
could approach the area tomorrow morning along with some rain
chances.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 9 PM EST this evening for KYZ051-052-
060-079-080-083>085-106.

&&

$$

SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS



Office: LMK FXUS63 KLMK 202009 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 309 PM EST Tue Feb 20 2018 .Short Term...(This evening through Wednesday night) Issued at 300 PM EST Tue Feb 20 2018 Afternoon temperatures across the region were generally in the upper 70s to around 80 in most places. A very late springlike day across the Ohio Valley. Louisville International has hit 82 in the last hour which is the highest maximum February temperature at the station. South to southwest winds of 15-25 MPH were common with occasional gusts to 35-40 MPH at times. The warm and breezy conditions will continue through the afternoon hours with the winds slackening off toward sunset. Look for temperatures to settle down into the 70s this evening before cooling off into the 60s later in the overnight period. A cold front out to the west will begin to move eastward late tonight. Showers, with a few rumbles of thunder will enter the region from the west/northwest late tonight. Best chances of precip will be west of the I-65 corridor. In fact, the eastern edge of the rains will should be reaching the I-65 corridor by 12Z Wed morning. The front will push through the region on Wednesday with widespread showers being seen across the region. Temperatures will fall behind the front with daytime highs on Wednesday likely occurring around midnight tonight. By late afternoon, temperatures should range from the lower 40s in southern Indiana to the lower 60s around the Lake Cumberland region. Rainfall amounts from late tonight through Wednesday afternoon should run around 0.50 to 1.00 inch west of I-65 with 0.25 to 0.50 east of I-65. It does not appear that significant runoff will occur with this activity. However, this will just prime the soil up for more runoff later this week. Frontal boundary looks to slowly stall out to our southeast Wednesday evening. Moist southwest flow aloft will continue to transport moisture into the region. So widespread rain showers look likely through much of Wednesday night. Lows should exhibit a gradient from south to north with lows in the upper 30s to the lower 40s across southern Indiana and upper 40s to the lower 50s across the areas along the KY/TN border region. && .Long Term...(Thursday through Tuesday) Issued at 300 PM EST Tue Feb 20 2018 ...SIGNIFICANT LONG DURATION RAINFALL EVENT UNFOLDING FOR LATE THIS WEEK AND INTO THE WEEKEND... ...FLOOD WATCH FOR ALL OF SOUTHERN INDIANA AND MUCH OF CENTRAL KENTUCKY THROUGH SUNDAY... The highly amplified upper level pattern is expected to remain in place throughout the remainder of the week and into the weekend before flattening out early next week. The pattern will feature a trough in the western US and a ridge in the eastern US. The Ohio Valley will remain in between with a deep southwest flow of moisture and in the main storm track. Multiple perturbations will move through within the mean flow brining multiple rounds of moderate to occasionally heavy rainfall to the Ohio Valley. The aforementioned front from the short term period is forecast to stall out to our southeast by early Thursday. Much of the rainfall will shift from our western areas to our southeast areas for Thursday. In fact, we could see a decent break in the precipitation during the day on Thursday as we await for the next weather system to arrive from upstream. By Thursday night, the next wave will approach from the southwest. The frontal boundary to the south will zip back to the north as a warm front and we'll be on the warm side again. Multiple rounds of showers and a possibly a few thunderstorms will be possible from Thursday night into the day on Friday. Heavier rainfall may refocus a bit more to our west Friday night as the warm front surges back to the northwest. By Saturday, a stronger perturbation aloft will move into the Plains which will induce surface cyclogenesis in the Plains. This feature will move northeast Saturday afternoon and evening bringing a cold front through the region. The GFS is particularly aggressive with its instability. CIPS Analog guidance suggests the potential for severe weather Saturday afternoon and Saturday night across the TN Valley and into the Ohio Valley. The details remain a bit unclear, but there is a clear signal for a low-topped convective event with wind damage being the primary severe weather threat. So this will bear watching over the next few days. The cold front should push through and end the long term heavy rain threat by Sunday afternoon with drier conditions anticipated for Monday and into Tuesday. As for QPF, as mentioned below in the hydro section, the deterministic and ensemble runs are suggesting 3-6 inches of rainfall through Sunday. If this QPF is indeed correct, moderate flooding will be likely on many of our river basins. If the QPF ends up being more widespread on the higher end of the guidance, say 5-6 inches, moderate to potentially major flooding could occur at some sites. In addition to the river flooding, low-land, flood prone, and poor drainage areas could see hydro issues later this week. For this reason, we have hoisted a Flood Watch for the northwest 2/3rds of KY through Sunday morning. At this time, we have opted to keep our southeast areas (Lake Cumberland Region) out of the watch as the heaviest rainfall looks to remain northwest of that area. It is likely that this flood watch will be expanded eastward in subsequent forecasts. However, the current watch is in good agreement with the WPC Excessive rainfall forecasts that go out through three days. People with interests along rivers need to keep an eye on the forecast for the next few days. remember that river forecasts are available via the "Rivers and Lakes" link on our webpage at weather.gov/lmk. && .Aviation...(18Z TAF Issuance) Issued at 1255 PM EST Tue Feb 20 2018 Gusty SSW winds will continue through sunset, with gusts over 30 kts common. Peak gusts will be closer to 35 kts. It will remain breezy after sunset, so decided not to include LLWS tonight. There's not a notable inversion or strong wind shift tonight, but SW winds will still be up around 45-50 kts as low as 2 kft AGL. As far as clouds go, an afternoon cumulus field around 4 kft is forecast to increase in coverage. Mid-level clouds will increase overnight from the northwest and low-level clouds will move in early Wednesday morning as a surface cold front sags toward the Ohio Valley. Widespread rain showers and fuel alternate ceilings are likely to move in across all the TAF sites between 09-16z. Reduced visibility is likely at times as well in moderate to heavy showers. There is potential for IFR ceilings as well, which could impact HNB as early as 12z. Winds will shift northwesterly behind the front. && .Hydrology... Issued at 300 PM EST Tue Feb 20 2018 Minor flooding continues along the Ohio River at Tell City, Cannelton, and Louisville. Along the Green River, all the sites have dropped below flood stage, though this is just temporary. Thankfully, we have had a dry today to help dry out things. However, the latest forecasts continue to look ominous with a long duration heavy rainfall event on tap. Synoptic models continue to advertise 3 to 6 inches of rainfall through Sunday afternoon across much of the region. Some locally higher amounts will be possible depending on where multiple axes of heavier precipitation develop. The Euro and Canadian GEM generally agree with their heaviest rainfall from NE TX through western TN. The OP GFS and its ensembles continues to be further north with its axis across southern MO into southern IL and southern IN. We've gone closer to the Euro runs here which matches well with our previous forecast. In general, we currently have around 3-3.5 inches across the Lake Cumberland region with generally 5-6 inches in areas west of I-65. This rainfall combined with already saturated soils will lead to excessive runoff through the period. This will result in flooding issues in the typical low-land and flood prone areas. In addition, ongoing river flooding will become worse with time as the runoff makes its way into the rivers. Quick rises are expected later this week. Current river forecasts that are out are based on forecasts that contain only 48 hours of rainfall. Therefore, with the additional rainfall coming later this week, these river forecasts will likely trend upward over the next few days. Ensemble river forecasts suggest that some of our points will rise into the moderate flood range. It is important to note that there are some QPF forecasts that could push some of our points into major flood status. Again, these forecasts are *highly dependent* on where the heavy rainfall actually develops. Given the consistent and consecutive heavy rainfall forecasts from the guidance, a Flood Watch will be posted with this forecast update for the northwestern 2/3rds of KY and all of southern Indiana. This will be a long term flood watch that runs through Sunday morning. Residents of southern Indiana and central Kentucky should remain alert this week for flooding. Stay tuned for the latest forecasts and updates through the week. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...Flood Watch from Wednesday morning through Sunday morning for INZ076>079-083-084-089>092. KY...Flood Watch from Wednesday morning through Sunday morning for KYZ023>043-045>049-053>055-061>065-070>074. && $$ Short Term...MJ Long Term....MJ Aviation.....EBW Hydrology....MJ
Office: PAH FXUS63 KPAH 202108 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 308 PM CST Tue Feb 20 2018 .SHORT TERM...(Tonight through Thursday) Issued at 308 PM CST Tue Feb 20 2018 Will be issuing a Flood Watch for the entire area beginning at 9 PM this evening and running through 6 AM Thursday. Most of the area will get 2"-3" of rainfall in that period, and with the river flooding already ongoing in many locations, the runoff will have no place to go. We are not anticipating flash flooding due to a lack of prolonged convective rain rates, but rather just a gradual increase in standing water, especially along tributaries near the larger rivers. Most of the 12Z guidance indicates that we will either dry out or have a serious lull Thursday, especially in the northwest portions of the area. I fully expect that the watch will be extended through next weekend, but figured we would get the ball rolling with this initial shot of heavy rain and then see where we are heading into the weekend. SPC has Carter and Ripley counties in a marginal risk of severe weather for the expected cold frontal QLCS that will move through that area around 03Z. We will have very strong winds just off the surface, so any reasonably organized convection has a chance to transport that momentum to the surface. Definitely looking for just a very isolated damaging wind threat. The more intense portion of the frontal line of convection will be suppressed southward as it tries to move farther east into our area. We will limit the slight chance of thunder to the southwest portions of the region late this evening into the overnight hours. This is where the heaviest rain is also likely to fall tonight. The leading line of convection will be moving quickly, which should limit the flash flood threat. Another concern late tonight and through midday Wednesday is some potential for freezing rain and icing in our northwest border areas. Went with more aggressive cooling behind the front given the intense gradient to our northwest, but we manage to keep the entire area above freezing. However, with wet bulbing potential in our far northwest, the potential exists for a period of light freezing rain and some minor icing. If temperatures trend any cooler, a Winter Weather Advisory may be needed from Carter County Missouri through Jefferson County Illinois. The cold front will clear the entire area Wednesday morning, and the initial band of rainfall will be diminishing over the southeast half of the area during the morning. Unfortunately, the 12Z guidance is in decent agreement in bringing another swath of rain back across the area with another upper-level impulse Wednesday afternoon and night. The northwest extent of this swath is uncertain at this time, and the potential exists for northwest portions of the Flood Watch to be cancelled early. .LONG TERM...(Thursday Night through Tuesday) Issued at 308 PM CST Tue Feb 20 2018 The medium range models appeared to be in reasonable agreement regarding the western trof/eastern ridge longwave mid/upper pattern over the CONUS, even out in this time range. As usual, smaller details of timing of shortwave energy bundles moving through the longwave pattern were less certain. So, you might say that at least the first half of the extended forecast period will be a fairly high confidence forecast of a prolonged high PoP event, especially if you break the forecast into 12 hour increments. The PAH forecast area will be under another warm advection pattern early in the period in response to shortwave energy, with possible rising temps Thu night. A surface cold front just to our north is progged to sink partway into the region late Fri, and become quasi- stationary into the weekend before becoming diffuse. Some tstm activity will probably occur near this feature, but severe weather appears to be more likely just to our south. 850 mb moisture transport into our area will be impressive, especially Thu night/Fri morning, and again Fri night through Sat. Accompanying these surges, precipitable water numbers peak above two standard deviations in the models for this time of year. This scenario should result in several inches of rainfall for our region, which will tend to aggravate areal and river flooding conditions from earlier pcpn. Additional flood watches will be likely. The mid/upper pattern should become more zonal for the latter half of the weekend as the Gulf should finally get cut off as a moisture source. The forecast looks mostly dry and mild through Day 7 (Tue). && .AVIATION... Issued at 1152 AM CST Tue Feb 20 2018 Very gusty south southwest winds will be the rule this afternoon and possibly into the evening with gusts to 30-35kts possible. A cold front will turn the winds to the northwest as it passes late this evening and into the overnight hours. Some gustiness can be expected through at least daybreak. Conditions will rapidly deteriorate as the front arrives. There will be a couple hour window of some heavier rains and possibly some TS with and just behind the front. Ceilings are likely to drop to IFR levels behind the front and linger through the rest of the forecast, as showers continue. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Flood Watch from 9 PM CST this evening through late Wednesday night for ILZ075>078-080>094. Wind Advisory until 6 PM CST this evening for ILZ075-080-081-084- 088-092. MO...Flood Watch from 9 PM CST this evening through late Wednesday night for MOZ076-086-087-100-107>112-114. Wind Advisory until 6 PM CST this evening for MOZ076-086-087-100- 109>111. IN...Flood Watch from 9 PM CST this evening through late Wednesday night for INZ081-082-085>088. KY...Flood Watch from 9 PM CST this evening through late Wednesday night for KYZ001>022. && $$ SHORT TERM...DRS LONG TERM...DB AVIATION...DRS