The weather pattern remains very active. In fact, we are bracing for another very strong blast of Arctic air due to arrive Wednesday. There is also the potential for some more ice. I will keep the blog in short form through at least Wednesday until we see everything unfolds. Also, as time permits either later this week or early next week, I will rehash last week's ice storm that affected the entire forecast area to a certain extent. I will compare it to the big ice storm in 1997, and set up exactly how things came together to produce the freezing rain and sleet, and the most influential ice storm around these parts since the epic ice storm in 1997. I will also critique myself and compare what happened to what was forecasted. Again, look for that later this week or early next week when things calm down.
Click below for the latest edition of the video blog. Be sure to scroll down for the text block of the blog.
SW Louisiana Forecast Discussion...It is hard to fathom now that we had an ice storm last week, especially after the beautiful weekend and the substantial warm up after Saturday morning's hard freeze. Temperatures rebounded all the way into the normal category Sunday afternoon with readings in the low to mid 60s. Of course, clouds rolled in Sunday afternoon, and then came a brief storm last night after the game. That was ahead of the first of two cold fronts on the docket this week. The short term forecast is the easy part. I will get into the tough part of this forecast with more specificity in a minute. For tonight, a freeze is expected across the area with high pressure in control and clear skies abound. This comes on the heels of last night's front. Today was a pretty day as the clouds this morning gave way to plentiful sunshine before noon. Temperatures warmed up into the 50s, but this didn't feel too bad compared to last week when we didn't get out of the 30s for 3 days. Tonight, we will drop off quickly into the mid 20s north to the upper 20s along I-10 and lower 30s at the coast. Freezing temperatures are expected into the coastal parishes, but the immediate coast may avoid freezing conditions tonight. The same course of action we have done hundreds of times should be conducted tonight...protect your plants and pets. The pipes shouldn't be an issue this time around. It will be a cold and quiet start to the day on Tuesday with plenty of sunshine to go around. There could be some areas of frost at sunrise, but that won't be a big issue.
Tuesday won't be a bad day. We'll be in between systems. A very fast and amplified NW flow aloft is present across the Eastern 2/3 of the Lower 48. The current controlling high pressure will slowly slide Eastward during the day orienting itself over Dixie by the afternoon hours. The cold start will transition into a seasonably cool afternoon. Temperatures will wind up in the low to mid 50s across the area. This is roughly 10 degrees below the benchmark for the beginning of the second week of February. Plenty of sunshine will be present to start the day, but an increase in clouds will be noted by the mid-late afternoon hours as our next system begins to move closer to the region. Forcing will increase as early as Tuesday night as a strong Arctic front moves through the Great Plains towards the Red River Valley. Cloudiness continues to increase, and an Easterly flow will intensify over the region. It will remain cold. Low temperatures will drop into the mid to upper 30s. Rain chances are introduced after midnight as the front itself continues driving SE. Also in the mix, will be an additional piece of energy embedded in the Jet Stream. This disturbance will help fire off periods of cold rain after midnight. This will induce another period of overrunning across the forecast area. Rain chances will be in the 30-40% range in the pre-dawn hours of Wednesday. Wednesday will by far be the worst weather day of this week. The big system will arrive at this time.
Rain chances will be on the up and up at mid-week. There are a combination of factors that will trigger these rains. The aforementioned elements will be a big part of that. The cold front comes into play first. The front will quickly slide through the forecast area during the morning hours. It will advance into the coastal waters during the afternoon. Temperatures will rise a little bit ahead of the front. I am undercutting guidance, based on the fact that a significant winter storm will be unfolding to our North with snow likely on the ground. Temperatures will warm up into the mid to upper 40s ahead of the front. Rain will become widespread through the morning hours and into the afternoon as isentropic ascent increases. The front will usher in much colder air, and temperatures will start to fall in the afternoon. A very strong and active Jet Stream will increase forcing over the coastal waters, and a surface low will form and advect Eastward along the front. This low will continue to throw moisture up and over the landmass of SW Louisiana and SE Texas. Widespread rain will result, and some of it will be heavy especially Wednesday afternoon when convergence and lifting is at its greatest point. Some embedded thunderstorms are possible with upper level instability in place. Rainfall totals between 1-2" are expected across the forecast area. Winds will be quite gusty as well initially out of the East, but shifting to the NNW behind the front. Temperatures will likely wind up in the 30s by the mid afternoon hours. North Louisiana may receive significant snowfall as the Arctic air mass spills into the state. The rainfall will continue on a likely basis into the evening and overnight hours of Wednesday. This is when the biggest forecast challenge arrives.
Remember last week when it seems likely that a winter storm seemed imminent. That is not entirely the case this time around. However, there is a possibility of some icing problems again in the Wednesday night-Thursday morning time frame. Lingering moisture in the wake of the front, and the surface low will keep rain chances in the forecast. As temperatures continue to fall, we will fall below freezing all areas Wednesday night. That means a transition to freezing rain and/or drizzle will occur. However, this is not etched in stone as some model output suggests the rainfall will come to an end before the coldest air arrives as the boundary layer dries out. The amount of overrunning is the big question. We are close enough to this time frame now, and there is a little more consistency today such that I will include a chance of freezing rain/drizzle in the forecast for the given time frame. While the consistency is there that a surface low will form in the Northern Gulf, the exact track and strength of the low is still in question. A low tracking further to the South would increase the winter weather threat to this area. The Northern extremity of this forecast area may have a better chance of some snow this go around compared to last week. There will certainly be several inches of snow across North Louisiana, but my analysis indicates that rain may mix with or change to snow and sleet as far South as Central Louisiana by Wednesday night. Further adjustment to this forecast is expected on Tuesday. The models don't handle shallow cold air masses very well, and also have a hard time with overrunning.
Now, I mention the frozen precip (ice) possibilities, but it seems unlikely that any accumulation will even compare to the amounts experienced last week. As it stands right now, I would expect only a very thin accumulation of ice if any. However, it doesn't take much freezing drizzle or light freezing rain to cause numerous headaches. I will not mention a specific amount in the official forecast, but I will mention it here in the discussion for now until more clarity arises on Tuesday. Freezing drizzle/freezing rain amounts should generally be between 0.01" and 0.10" per my analysis today. In short, what this means in general terms is that it is a question of whether or not the precip ends before the coldest air arrives. It will certainly be cold enough behind this front to support a transition to frozen precipitation, but how long will sufficient moisture be around. Temperatures will fall into the mid to upper 20s Wednesday night and Thursday morning. It will quite windy as well with wind chills back in the 10s. This is the Arctic air mass I briefly mentioned last week amid the ice storm dissertation. If you have travel plans into North Louisiana at mid-week you will want to re-consider as a Winter Storm Watch has already been posted for that region including Shreveport, Ruston, Monroe, and Tallulah. There is no hope for snow here along I-10. Ice is our threat, if any at all. CAA will strengthen as we head into Thursday, and precipitation will be winding down.
Thursday will be cold and windy. Clouds will linger for much of the day. A small chance of freezing drizzle/rain is maintained in the morning hours in case it takes a while for all levels of the atmosphere to complete sufficient drying. Most of the day will be precipitation free as it stands at this juncture, but temperatures will struggle. We will have a hard time getting into the 40s with continued CAA and a cloud canopy in place. Clouds will begin to decrease late in the day as strong Arctic high pressure over the Rockies Thursday slides down into the forecast area. Cold air will continue filtering into the region via strong Northerly winds in the 15-20 mph range at times. This will keep wind chills in the 20s throughout the day. Clearing is expected to finish by Thursday night, and that will set the stage for a very cold night with radiational cooling in effect. Morning lows for Friday will in the hard freeze category. Low to mid 20s seem like a good call across the forecast area. That is certainly well below normal heading into the middle of February, roughly about 20 degrees colder than usual. That is not record breaking though, as records around that time are in the single digits and lower 10s which occurred during the mother of all Arctic breaks in February of 1899 (more on this in the coming days). I feel I will need to undercut guidance, however, given the snowpack over North Louisiana. Models don't take this into consideration either.
The cold Arctic air will be in place for Friday, but Friday should be a day full of sunshine. Don McLean's lyrics from "American Pie" will reign true this week...sing it with me now..."February made me shiver, with every paper I delivered." Despite wall to wall sunshine, the daytime highs on Friday will only be in the mid 40s at best as the winds continue to come off the snow covered ground to our North. CAA will cease later in the day as the Arctic high slowly begins to slide Eastward during the day. The wind chill will be very close to the actual temperature Friday morning with light surface winds in place. It won't be quite as cold Friday night, but the Arctic air will be slow to leave. Another freeze is on tap for the Friday night-Saturday morning time frame setting the stage for a cold start to the second weekend of February...Valentine's weekend. Expect morning lows to be in the mid to upper 20s across the area with the coldest readings from the East Texas Piney Woods to Central Louisiana. The coastline may avoid a freeze this night, but it'll be just above freezing with a good deal of frost even down there. Saturday a nice, a perhaps prolonged, warm up ensues. The upper flow will transition from NW to zonal, and the pattern will be far less amplified across the NW Gulf of Mexico. A more Pacific influence generated by Westerly winds will cause temperatures to rebound nicely back into the upper 50s or so across the region. Very dry air will be in place, so expect humidity values to be low.
The second half of the week looks just as grand. This may turn out to be the prettiest weekend of the year so far, as it stands right now. The warm up continues Sunday with a chilly morning on tap. Temperatures will be close to freezing to start the day. The dry air in place will allow for quicker radiative processes at night, so temperatures will drop into the cold category. Frost looks likely for Sunday again. Listen to this, though, highs on Sunday afternoon should eclipse the 60 degree mark, and top out close to normal with the continued string of low humidity afternoons remaining in tact as the Gulf remains shut down due to some Pacific high pressure replacing the Arctic high. The return flow does commence on Monday, Valentine's Day itself. We should round out this forecast period on a dry note if the current projections hold true. Moisture levels will increase, and the warming trend will continue. However, it will mostly be reflected in morning lows be this point. Model output suggests we may reach or exceed 70 degrees for maximums by next week, but with a cool continental shelf temperature over the Gulf of Mexico waters this seems unlikely at this point. Last week's Arctic blast cooled off SSTs into the 40s in the Gulf. The marine influence will inhibit temperatures from getting as warm as models suggest. However, mid 60s are plausible as the zonal flow is well established by this time. The increasing moisture at day 7 will lead to our next rain chance just beyond the forecast period around next Tuesday into Wednesday. It is too soon to speculate on how big of a chance of rain this'll be, if we'll have a thunderstorm threat, or if it we'll be getting ready to make a transition back to a colder pattern at that time. Any number of solutions is possible that far out. The long range models suggest the warmer weather will dominate for the latter half of February. We shall see!!! Stay tuned for more on the ice possibilities for Wednesday night-Thursday morning!
Preliminary Numbers & Zone Forecast:
LCH 28/53 36/48 27/41 0 0 30 80 40 20
LFT 28/52 35/48 29/43 0 0 20 80 40 30
BPT 29/54 37/50 27/42 0 0 30 80 40 20
AEX 25/48 34/44 24/37 0 0 30 90 40 20
POE 25/48 34/44 24/37 0 0 30 80 40 20
ARA 30/53 38/49 30/44 0 0 20 80 40 30
Tonight...Clear & Cold w/ a Freeze. Low 28. Light North wind.
Tuesday...Sunny for most of the day w/ Increasing Cloudiness late. High 53. NE wind 5-10 mph becoming East in the afternoon.
Tuesday Night...Mostly Cloudy & Quite as Cold with a 30% chance of rain towards daybreak. Low 36. East wind 10 mph.
Wednesday...Cloudy, Windy, & Cold w/ rain & a few thunderstorms likely. High 48. Temperatures falling back into the 30s late. Rain heavy at tines along w/ a chance for isolated thunderstorms. East wind 10-20 mph in the morning, but becoming NNW at 15-25 mph and gusty in the afternoon. Rain possibly changing to freezing rain and/or freezing drizzle late. Chance of precipitation 80%.
Wednesday Night...Cloudy & Cold w/ a chance of freezing rain and/or freezing drizzle. Low 27. NNW wind 15 mph and gusty. Chance of precipitation 40%. Wind chills 10-15 by morning.
Thursday...Cloudy & Cold with a 20% chance of light freezing rain/drizzle or light rain in the morning. Slow clearing through the day. High 41. North wind 15 mph & gusty or so. Wind chill readings in 20s.
Tuesday 2/8/11 Daily Planner
6a.m.
Weather: Clear & Cold w/a Morning Freeze
Temp: 28
Rain: 0%
Wind: N 4
W.C.: 25
9a.m.
Weather: Sunny
Temp: 38
Rain: 0%
Wind: N 6
W.C.: 35
Noon
Weather: Sunny
Temp: 45
Rain: 0%
Wind: NE 8
W.C.: 40
3p.m.
Weather: Sunny
Temp: 53
Rain: 0%
Wind: E 6
6p.m.
Weather: Partly Cloudy
Temp: 48
Rain: 10%
Wind: E 7
9p.m.
Weather: Cloudy
Temp: 44
Rain: 10%
Wind: E 10
Drew's 7 Day Outlook
Tuesday
2-8-11
Low: 28
High: 53
Rain: 0%
Wind: ENE 10-15
W.C.: 20-30
Wednesday
2-9-11
Low: 36
High: 48
Rain: 80%
Wind: E/NNW 15-25
W.C.: 20-40
Thursday
2-10-11
Low: 27
High: 41
Rain: 20%
Wind: N 15
W.C.: 20-35
Friday
2-11-11
Low: 24
High: 45
Rain: 0%
Wind: N 10
W.C.: 20-40
Saturday
2-12-11
Low: 27
High: 54
Rain: 0%
Wind: NW 5-10
W.C.: 20-35
Sunday
2-13-11
Low: 32
High: 62
Rain: 0%
Wind: W 5-10
W.C.: 25-40
Monday
2-14-11
Valentine's Day
Low: 44
High: 65
Rain: 0%
Wind: SW 10
...Marine Forecast....
Tonight...North winds 15 to 20 knots becoming northeast 10 to 15 knots after midnight. Seas 1 to 2 feet.
Tuesday...East winds 10 to 15 knots increasing to 15 to 20 knots in the afternoon. Seas 1 to 2 feet building to 1 to 3 feet in the afternoon.
Tuesday Night...East winds 15 to 20 knots. Seas 1 to 3 feet. A slight chance of rain after midnight.
Wednesday...East winds 15 to 20 knots increasing to 20 to 25 knots in the afternoon. Seas 2 to 4 feet. A slight chance of rain early in the morning...then rain likely and scattered thunderstorms in the late morning and afternoon.
Wednesday Night...Northeast winds 20 to 30 knots becoming north 20 to 25 knots after midnight. Seas 2 to 3 feet building to 2 to 4 feet after midnight. A chance of rain.
Thursday...North winds 15 to 25 knots becoming 15 to 20 knots in the afternoon. Seas 2 to 4 feet.
Have a great Tuesday & God bless!
-DM-
No comments:
Post a Comment