Archive for January, 2011

winter storm watch far north ky

January 30, 2011

A winter storm watch has been issued for far northern KY.  I could see ice accumulation under 1/4 inch by Tuesday morning. As is usual with ice events it will depend on how much WAA streams north and how long the low level cold can linger.

1. On Monday a storm forms over the southern Rockies along an arctic boundary our region will be south of the boundary with light rain showers likely during the day and highs from the 50’s in the south to the 30’s north which presents the threat for ice Monday night into Tuesday. I actually think Tuesday will be dry in most places with some sun strong WAA will temps to climb close to 50 north and in the 60’s south Tuesday. This leads to a band of rain and storms with the low pressure Tuesday night which i could see containing a squall line of thunderstorms from AL into TN and perhaps even southern KY, gusty winds will be the main threat with an isolated tornado not ruled out due to high shear. overall rainfall for this event mon-Tue should be from 1 to perhaps 2 inches.

Let’s take a look at the NAM timeline of this storm

Tuesday noon

Tuesday 6 pm

Tuesday night  midnight

Wednesday morning

I also expect winds to 30 mph with the frontal passage Tuesday night. Flurries may fall on Wednesday with cooler conditions.

The main chance for snow comes from a secondary low for fri-sun. I expect modeling to come further north and west with time for this feature with the exception of the 12z cmc and ecmwf. In my view the upper air pattern argues for low pressure to form off the texas coast friday and move into the southeast saturday and into the mid-atlantic Sunday and the models near the southeast coast will correct north and west.

spring preview today

January 29, 2011

we see many temperature busts with modeling and forecasts underdoing the WAA ahead of a week clipper which will pass well to our north. This will result in melting of the persistent snowcover across the region. Highs today will be in the 50’s with BWG near 60. Tonight I still expect lows to fall into the 30’s. I’m going with the warmer ECMWF Sunday for highs in the low to mid 50’s Sunday for the south and 40’s north keeping clouds away Till Sunday night .

An arctic boundary moves into the upper Ohio valley with rain developing along it for Monday through Tuesday night. In fact I like the ECMWF continuing to take this low over Paducah keeping any freezing rain threat minimal and bringing a severe threat from AL into TN and perhaps southern and southeast KY. The 12z ECMWF surface output can’t be shown due to copyright laws. Any severe threat for the south would be shear not instability driven with gusty winds the main threat. Other wise I expect the region to see a soaking rain of 1 to perhaps 2 inches from monday night through early Wednesday. I expect highs in the 40’s Monday with Monday night around 32 north which could lead to a brief period of frz rain for CVG and highs again well into the 40’s and 50’s Tuesday.  By Wednesday the cold front swings through behind the storm and we end up with flurries and temps in the 30’s as southerly winds shift to northwesterly.

This boundary stalls late week over the south and in my view is ideal for the secondary low theory with the ecmwf,cmc and jma all showing this my confidence is higher than usual with secondary lows. My thinking is this should be snowmaker here if there is one this upcoming week. timing would most likely be Saturday.

notice how we’re warm for most of this week and have been cold all winter?  the cold has mainly due to the AO through mid JAN and the PNA till now. notice the PNA going strong negative which is not a cold signal . The AO is positive this week but may go negative around the 7th again. But for this week for the first time all winter no teleconnections are governing cold and the la-nina can have some influence.

AO

PNA

GFS rainfall Mon-Tue, ECMWF is lighter

The the groudhog will be waiting for two things to determine if he sees his shadow this week

1. if the AO projections next week for mid month go positive

2. The ECMWF weeklies ( since I haven’t seen them yet)

first thoughts on next storm

January 27, 2011

– 14 day updated as well with day to day details

– I actually like the gfs solution from 00z on this next storm

why?

– high pressure should keep it from cutting into the lakes however the low may be strong enough to track further north and pull north warm air, this deviation of the low track takes into the TN/OH valleys before transferring energy to the east coast. This is a classic cold rain track.

not giving myself high marks on last forecast

January 26, 2011

this was either  a bust or surprise snow no middle ground and a forecast nightmare. Looking at the many mistakes on my near failing report card for this storm I see in some spots where I should have seen things. Throughout the week the trend wasn’t west in the low track it was the modeling picking up on the upper low.

1. the upper low was trending northwest a clear giveaway southeast KY would stay warmer longer

2. the original forecast worked better than the updates  it’s like changing an answer on a test usually not good outcome

3. still have having a difficult time grasping mesoscale banding setups with heavy snow, already looking forward to the 2/17 lecture in mesoscale class on this!

However model performance was also very poor i will say the CMC and JMA did better than usual.

moving on we have a FIRST CALL on a clipper for friday.

– should be a week one once again it’s a week system diving in from the northwest with WAA to the south of the track and light snow on the northern edges. this should track southeast through eastern Kentucky friday morning. Northeast of Lexington a 6 hour period of light snow may leave 1-2 inches of snow with 10:1 ratios.  As usual the NAM overdoes qpf.  This may create slick spots for the Friday morning commute. There should be a sharp- cutoff further southwest with light snow showers and sprinkles.

In the long range we have the 12z euro calling for a lakes cutter on Tuesday. the remainder of the models through 00z gfs call for a sloppy mix across the region. I think the arctic high over the upper midwest will prevent a lakes cutter. However that does not mean a low still cuts up into the region providing mainly a cold rain before transferring to the east coast and we get little snow. Of course there’s still a track to our southeast in which case snow. so my thinking for a while for a winter storm around the 1st holds.

8:30 am update: snow still for eastern Kentucky

January 26, 2011

– a dry slot has worked into the Somerset region as the system worked further north than expected

– accumulations occurred in bands overnight this threw off totals in a lot of places

–  this morning we have one band working south toward lake Cumberland and Somerset with a shield of snow over eastern Kentucky.