Monday, July 31, 2006

One More Hot Day...

Today was the hottest day in several years, with a high of 103 degrees. Dewpoints fell into the middle 60s during the day, so heat indices were only a few degrees above the actual air temperature, but it still felt quite oppressive. Tomorrow should be the last really hot day, before more seasonable temperatures settle in for a few days. High temperatures tomorrow will be highly dependent on how many clouds are around. Thunderstorms developed along a cold front across western Minnesota this evening, and debris cloudiness from these storms could linger for much of the day tomorrow. Nonetheless, high temperatures are still expected to reach the 90s, especially as the front nears the area. As the front edges closer, it will compress the air ahead of it, which will cause temperatures to rise. Moisture will also pool along the front, creating very humid conditions. Severe thunderstorms are possible tomorrow evening into Wednesday as the front moves through, but the biggest threat appears to be very heavy rainfall. More on that tomorrow as the situation becomes clearer. In the meantime, it is 9:34 p.m. and still 87 degrees outside. Still better than -20 though.

Sunday, July 30, 2006

Still Hot...

Thunderstorms did develop overnight across northern Wisconsin and took a scary southward turn at one point, prompting a severe thunderstorm watch for the western half of Wisconsin. Obviously, this was not supposed to happen. Storms did manage to stay just east of the area, but lingering clouds keep temperatures down in the morning. There was some partial clearing in the afternoon, and temperatures "only" managed the middle 90s, as opposed to the upper 90s that were predicted. Tomorrow should be a different story. The axis of the extreme heat should move across the region during the day, and southerly winds should bring a steady stream of hot and humid air northward. The result should be temperatures near 100 degrees, with heat indices of 110 to 120 degrees. A heat advisory remains in effect through Tuesday. Currently, it is still 81 degrees outside, with a dewpoint of 77 degrees. Needless to say, it will not cool off much tonight.

Saturday, July 29, 2006

Heat Wave Continues...

Debris clouds from overnight thunderstorms over northern Wisconsin kept temperatures in the 80s this morning. An outflow boundary from that convection moved through the area around mid-morning, dropping the temperature from 88 to 81 degrees, and dropping the dewpoint temperature from the lower 70s to the lower 60s. This was a very brief respite, however, as skies became partly sunny by afternoon and the heat and humidity increased. The high temperature today reached 97 degrees, while dewpoints topped out in the lower 70s. Tomorrow should be similar. Thunderstorms have not been able to develop over western Minnesota tonight, which could be important for tomorrow's high temperatures. If these storms manage to get going overnight, they will likely move toward northern Wisconsin, and the debris cloudiness from them could keep skies mostly cloudy here tomorrow morning, just like today. If these storms don't develop, it should be mostly sunny all day tomorrow, and temperatures could be a few degrees higher than today. Highs for the next three days are expected to be in the upper 90s, but some 100-degree readings are possible all three days. Currently, it looks as if Monday will be the warmest day. Dewpoints will increase into the middle 70s, creating heat indices of 105 to 115 degrees. A heat advisory goes into effect at noon tomorrow, and will last through Tuesday evening.

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE LA CROSSE WI
949 PM CDT SAT JUL 29 2006

...HOT AND HUMID CONDITIONS EXPECTED FROM SUNDAY AFTERNOON THROUGH TUESDAY...

.A STRONG RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA SUNDAY AND REMAIN IN CONTROL OF THE WEATHER THROUGH TUESDAY. THIS HIGH WILL BRING MUCH ABOVE NORMAL TEMPERATURES AND HUMID CONDITIONS TO THE AREA FROM SUNDAY AFTERNOON INTO TUESDAY. THIS HUMID AIR WILL NOT ALLOW THE TEMPERATURES TO COOL OFF AT NIGHT...THUS THERE WILL BE LITTLE RELIEF FROM THE EXCESSIVE HEAT.

FROM SUNDAY THROUGH TUESDAY...AFTERNOON TEMPERATURES WILL RANGE FROM 95 TO 105 DEGREES. THE COMBINATION OF THESE TEMPERATURES AND DEW POINTS IN THE 70S WILL PRODUCE HEAT INDICES IN THE 105 TO
115 DEGREE RANGE. A FEW LOCATIONS ACROSS NORTHEAST IOWA COULD SEE HEAT INDICES AS HIGH AS 120 MONDAY AFTERNOON. IN ADDITION...THE HIGH DEW POINTS WILL KEEP LOW TEMPERATURES IN THE MIDDLE AND UPPER 70S AT NIGHT. THIS WILL PROVIDE LITTLE RELIEF FROM THE HEAT.

A HEAT ADVISORY MEANS THAT A PERIOD OF HOT TEMPERATURES IS EXPECTED. THE COMBINATION OF HOT TEMPERATURES AND HIGH HUMIDITY WILL COMBINE TO CREATE A SITUATION IN WHICH HEAT ILLNESSES ARE POSSIBLE. DRINK PLENTY OF FLUIDS...STAY IN AN AIR-CONDITIONED ROOM...STAY OUT OF THE SUN...AND CHECK UP ON RELATIVES AND NEIGHBORS. ALSO MAKE SURE PETS AND LIVESTOCK ARE KEPT COOL AND HAVE PLENTY OF AVAILABLE WATER.

Friday, July 28, 2006

Hot Again

The second heat wave of the month has begun, and should last for several days. Temperatures have actually been 90 degrees or above since Monday, but reached the mid-90s today as dewpoints rose into the lower 70s. Sunday, Monday, and Tuesday should be the hottest days, with temperatures approaching 100 degrees. It will be more humid during this heat wave than the one earlier in the month, so heat indices will be higher, making it feel much more uncomfortable. A heat advisory will likely be issued for the area by Sunday.

There is an outside chance for some storms tomorrow, but the best chances will remain far to the north. One or more rounds of severe thunderstorms will affect much of northern Wisconsin, with a chance for damaging winds. If anything, debris cloudiness from these storms could keep temperatures slightly lower tomorrow (lower 90s instead of mid 90s). Many parts of the state have seen significant rainfall this week, but not here. A whopping three-hundredths of an inch fell in my rain gauge on Tuesday, and that was all. Stationary thunderstorms brought three to five inches of rain to Madison yesterday, causing quite a bit of damage. There was some flooding in the University of Wisconsin campus buildings, but fortunately it was in all of the buildings that I didn't like while I was there (the Computer Sciences building can float away, for all I care). :) After tomorrow's slight rain chances, the best chance for any significant rainfall, which is still badly needed in some places, will come late Tuesday into Wednesday of next week. Until then--hot.

Thursday, July 20, 2006

Rain (Finally)

Yesterday's severe weather forecast was not a total bust like most have been this season, but it certainly wasn't perfect either. The first round of storms yesterday morning persisted much longer and developed further south than anticipated (Severe Thunderstorm Watch #1). Fortunately these storms weakened as they moved into western Wisconsin, but there were a few reports of wind damage in some counties in southern Minnesota. Some places received some beneficial rains from the morning batch of storms, especially in Minnesota and Iowa.

The longevity of the morning storms put the afternoon and evening severe weather risk in doubt, as skies remained cloudy all day with scattered showers and storms strewn across the area. By late evening, however, conditions were coming together for additional storm development across southern Minnesota and northern Iowa. Storms began to explosively develop in this region after 9:00 p.m., and moved east toward Wisconsin (Severe Thunderstorm Watch #2). As with the morning storms, there were a few reports of severe weather, but most places just saw a lot of heavy rain. Rainfall totals of one to three inches were common. This rain came just in time, as most of the region (except for far southern Wisconsin) was on the brink of a drought situation. While more rain is probably needed in a lot of places, this was a step in the right direction. These thunderstorms strengthened as they moved into south central Wisconsin early this morning, and there were more widespread reports of wind damage.

For the most part, thunderstorms developed about where they were expected to yesterday, but weren't quite as strong as anticipated. The moderate risk was probably overdone, but a slight risk was definitely warranted. No more severe weather in the forecast for the next several days.

Wednesday, July 19, 2006

Widespread Damaging Winds Possible

Update--10:00 p.m.: Thunderstorms are finally beginning to redevelop over south central Minnesota, and a Tornado Watch has just been issued for areas west of the Mississippi River. A thunderstorm complex is expected to form and move across the region overnight, bringing a threat of damaging winds, large hail, and heavy rain. Things didn't quite pan out the way they were expected to today, but the severe weather threat nonetheless continues for the next several hours.

Previous entry: Today will be a very interesting weather day. There is currently a moderate risk for severe thunderstorms, mainly this afternoon and evening. A line of strong thunderstorms is currently moving eastward across Minnesota and will likely affect at least part of the region late this morning. Additional thunderstorms are expected to develop over south central Minnesota early this afternoon. All of the conditions for significant severe weather are forecast to be in place. These storms are expected to develop into a squall line and move east into western Wisconsin and adjacent areas of southeast Minnesota and northeast Iowa late this afternoon into this evening. If everything comes together the right way, widespread damaging winds are possible, along with very large hail and possibly a few tornadoes. Heavy rain will also be a threat, as copious amounts of moisture will be available. The Hydrometeorological Prediction Center paints a bullseye of 3 to 4 inches of rain right over southwest Wisconsin, and indicates that isolated 5-inch amounts could be possible.

As always, the forecast is far from certain. Indeed, most severe weather forecasts for our region have been wrong so far this season, but forecasters seem to be especially confident about today's situation. This is definitely something to be monitored as the day progresses. It will also be interesting to see what kind of effect the first round of storms currently moving across Minnesota has. They could stabilize the atmosphere and prevent significant redevelopment later today, or they could reinforce the warm front to the south and create even more volatile conditions. The latter scenario appears more likely at this time. I'll have updates as conditions warrant. In the meantime, read this Public Severe Weather outlook issued by the Storm Prediction Center. These are only issued when a widespread outbreak is expected, and is the first one issued for our region this season: http://www.spc.noaa.gov/products/outlook/pwo.html

Monday, July 17, 2006

HOT pt. 2

No thunderstorms tonight, so the dry weather continues. I wouldn't be surprised if the moderate drought area is extended further south when the new drought assessment is issued on Thursday. In the meantime, the hot and humid weather will retreat southward, for about a day. A cold front moved through this evening, and dewpoints have already dropped off into the middle 60s, after reaching the middle 70s today. High temperatures are expected to be "only" in the upper 80s tomorrow, and the humidity will be much lower. However, the front that went through tonight will move back north as a warm front late tomorrow, bringing a chance for thunderstorms and warmer and more humid air for Wednesday. Currently, temperatures are expected to remain near or slightly above normal for the next several days.

Today actually ended up being the hottest day of the heat wave. Some local high temperatures included 100 degrees in Lansing and Winona, 99 degrees in La Farge, La Crosse, Fort McCoy, Friendship, and Muscoda, and 98 degrees in Black River Falls, Mauston, and Boscobel. Heat indices were in the 105 to 110 range. Fortunately these numbers will be much lower tomorrow, but the heat index could push 100 degrees again by Wednesday.

HOT

After a high of 99 degrees today, a Severe Thunderstorm Watch is now in effect. However, the window for local storm development is rapidly closing as a cold front pushes through the region. If thunderstorms do not develop by 6:00 this evening, the severe threat will be over. More later...

Saturday, July 15, 2006

Not Quite 100

Definitely hot today, but no place nearby officially reached 100 degrees. Locally it was around 96 degrees (in La Farge), with 98 in La Crosse and Necedah, 99 in Winona and Medford, and 97 in Mauston and Fort McCoy. Further north, where dewpoints were much lower, a few locations did reach the century mark, including Eau Claire, Rhinelander and Superior, and 105 degrees in Hayward. The ground is also much drier in this region, so temperatures could get a few degrees warmer. Tomorrow should be much the same as today, but perhaps a few degrees warmer, so 100 degrees is still possible. However, dewpoints will be slightly higher tomorrow than today. This will make it a little more difficult to reach 100, but it will also create higher heat index values, and as a result a Heat Advisory has been issued. Monday still looks like it could be quite oppressive also.

Friday, July 14, 2006

Drying Daily

Appreciable rainfall has been scarce in recent weeks, and with each passing day a drought continues to develop. Much of northern Wisconsin is already suffering from a moderate to severe drought, while most of the local area is classified as abnormally dry. Rainfall deficits since May 1st range from one to three inches across the region, and the increasingly hot conditions are making the situation worse. Storms moved through the region overnight last night, but rainfall amounts were mainly light (nonexistent in La Farge), so these storms provided little relief. Not a good situation as we head into what is typically the warmest part of the year.

Temperatures near 100 degrees still appear likely Saturday and Sunday, and I wouldn't be surprised if Monday ends up being just as hot. For some reason, it always seems like the first day that is supposed to be slightly "cooler" in a prolonged period of hot weather ends up being the hottest. High temperatures are expected to remain in the 90s for all of next week. I highly suspect that a Heat Advisory will be issued tomorrow morning for Saturday and Sunday.

Thursday, July 13, 2006

Heating Up

After several relatively inactive weather days, changes loom on the horizon. The first real heat wave of the season is expected to develop across the region beginning tomorrow. A ridge of high pressure will build across the Upper Midwest, and will produce some very hot temperatures. High temperatures in the lower to middle 90s are expected Friday, and the mercury may approach 100 degrees on Saturday and possibly Sunday. A cold front may try to sweep through early next week, knocking temps back into the more seasonable 80s. In the meantime, expect some very hot and humid conditions. Heat index values could approach 110 degrees on Saturday afternoon, which is far into the danger category. This would definitely be a good weekend to stay inside in front of the air conditioner.

If we do manage to hit the 100-degree mark, it would be the first time in five years it has been that warm. The last 100-degree reading in La Farge (at least by my thermometer) was on July 31st, 2001. In July of 1999, the high temperature exceeded 100 degrees three times (101 on the 23rd, 102 on the 25th, and 101 on the 30th). The warmest temperature of 2006 so far has been 93 degrees on May 29th, and we will likely exceed this sometime this weekend.

Warmest temperatures for the last few years:
2005: 98 degrees (July 17th)
2004: 92 degrees (August 3rd)
2003: 99 degrees (August 16th & 20th)
2002: 96 degrees (July 21st)
2001: 100 degrees (July 31st)
2000: 93 degrees (August 31st)
1999: 102 degrees (July 25th)
1998: 97 degrees (July 13th)
1997: 96 degrees (July 26th)

Tomorrow I'll discuss the developing drought situation, which will only be made worse by this weekend's heat.

Monday, July 03, 2006

Slight Risk Today

Update--9:58 p.m.: Another day, another blown severe weather forecast. Storms tried to get going this evening but just couldn't keep it together. One weak storm developed over Vernon County about an hour ago and brought some brief rainfall, but has already moved to the south, and the severe thunderstorm watch has been cancelled. At least the evening forecaster at the weather service in La Crosse explained (in an evening forecast discussion) why severe weather didn't develop--low level convergence was not as strong as expected, meaning winds were not coming together in the right way at the surface for storms to develop and keep going for several hours. We can only hope that the next severe weather forecast will be more accurate, but that sure hasn't been the case this year so far.

Update--4:48 p.m.: Severe Thunderstorm Watch just issued. In effect until 11:00 p.m.

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 580
NWS STORM PREDICTION CENTER NORMAN OK
435 PM CDT MON JUL 3 2006

THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND EASTERN IOWA
NORTHERN ILLINOIS
SOUTHEASTERN MINNESOTA
SOUTHERN WISCONSIN
LAKE MICHIGAN

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 435 PM UNTIL 1100 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

Update--11:44 a.m.: Severe risk remains the same with the 11:30 a.m. forecast. Someone please explain to me why Vernon County tested their weather sirens on a day when severe weather is actually forecast??

Previous entry: There is a slight risk for severe thunderstorms over the entire region today. The most favorable time for severe weather will be between noon and 9 p.m. this evening. Thunderstorms are expected to develop along a cold front dropping south out of Minnesota, and conditions are expected to be right for these storms to become severe. The main threats are damaging winds and large hail, with the possibility of a few isolated tornadoes as well. Skies are currently mostly cloudy, which would seem to inhibit severe storms. However, the atmosphere is already quite unstable, and some partial clearing is expected throughout the morning hours, which would add to the instability. According to the National Weather Service, a widespread severe weather event seems possible, but it is far from a done deal. Subsequent forecasts today will seek to clarify and refine just how significant this severe weather risk is. Updates to follow, if necessary.

Sunday, July 02, 2006

Round Two?

After yesterday's storms, today was a quiet weather day. However, round two of severe weather may arrive tomorrow. A cold front will move southward across the region tomorrow, and depending on the time it arrives, severe storms may be possible. If the front approaches the area late in the afternoon, as currently forecast, storm chances will be greater, especially if skies are mostly sunny tomorrow. If the front arrives earlier than expected, severe weather will be less likely. Damaging winds and large hail will be the biggest threats if severe storms develop.

There is a small chance that some storms could develop during the night tonight, as a stationary front over Iowa becomes the focus for convective development. While the best chances for stormy weather will remain well to our south, a few storms may make it as far north as southwestern Wisconsin. However, Monday afternoon should be the most favorable time for rain.

Saturday, July 01, 2006

We've Got a Hailer

Today's forecast of a slight risk of severe weather proved to be quite accurate. A line of severe thunderstorms rapidly developed across southwest Wisconsin and northeast Iowa between 5:00 and 7:00 this evening, and prompted a severe thunderstorm watch and several severe thunderstorm warnings. A warning was issued for Vernon County at 7:00, the same time I heard (on the scanner) reports of dime to quarter sized hail in Viroqua. It was then I realized that I only had a few short minutes to close the windows, take the towels off the clothesline, and bring a few plants inside before the storm hit. The storm was predicted to be at La Farge at 7:20, and the hail actually began at 7:17, and lasted for about five minutes. The largest hail was about dime-sized, or about three-quarters of an inch in diameter--just big enough to be officially "severe" but not big enough to cause any damage. The winds were quite gusty at the height of the storm--enough so that I was being hit by a few hailstones even as I was standing outside my back door under the carport. While the hail was no bigger than that which fell during the same storm that produced the Viola tornado last summer, I think this hailstorm in general was more intense, with the hail falling harder and for a few more minutes. Also picked up a quick half inch of rain during the storm. Damage was limited to small twigs and leaves strewn about yards and streets, but there was some wind damage reported in Viroqua and Richland Center. Needless to say I had quite the experience this evening, trying to take pictures of the storm, pick up some hailstones and put them in the freezer, listen to the scanner for weather reports, and monitor the latest statements and radar images on the internet.

There remains a slight risk of severe thunderstorms on Sunday. While it appears the greatest threat will remain to our south, a stationary front will be close enough to potentially trigger a few thunderstorms, maybe severe ones, later tomorrow afternoon and evening.

Now I can enjoy a quiet evening, especially since the police have just put an end to the fireworks display going on in my neighborhood. Frankly the storm was more impressive.