FIRST WEEKEND OF AUGUST: COOLER THAN NORMAL
Chicagoans came off the first weekend of August—a weekend which was cooler than normal and sporadically wet in the city with drenching rains soaking southern sections of the metro area where as much as 4 to 6″ of rain was reported Friday night into Saturday—into a Monday which opened cloud but saw breaks in the clouds allow patches of blue sky and some mixed sunshine by and during the afternoon.

Monday will go into the books with a high of 79 and a low of 67—which average out 2.4-deg below normal. It’s the 3rd consecutive day to post a daily average temp deficit. Still. last week finished nearly a deg ABOVE NORMAL—this week is likely to post a 0.4-deg temp surplus with next week likely to approach a degree above normal. (NOTE: There has been a “cool bias” in recent official 6 to 10 and 8 to 14 day temp projections—a trend which seem likely to continue based on the latest forecasts and our in house model work).

We had logged THREE DAYS above 90 by this time last August; there’s only been one this August to date. But there could be several days in the next two weeks in which Chicago temps approach if not reach 90 over at least sections of the metro area — including later this week (Friday) and Tuesday, Friday, Sunday and Monday of the week which follows is current forecast trends verify.

NEXT TWO WEEKS: ABOVE NORMAL PRECIP TREND
A near to above normal precipitation trend appears likely to dominate overall the next two weeks in Chicago and areas close-by—though as this weekend’s precipitation trend show, warm season rainfalls are capricious—producing flooding downpours in one area while missing another all together.

The atmosphere is to be moderately “unstable” tomorrow—which means a few showers and t-storms may “bubble up” in the day’s warmer hours. Beyond that, a “wave” is to sweep across the area increasing shower and t-storm prospects Wednesday afternoon and night—and still another system may increase shower and t-storm prospects Friday afternoon and night. One more system could traverse the area early next week. So rain prospects are hardly “zero” this week.

The weekend came in close to 4-degrees cooler than last and generated virtually NO precipitation of significance north of the city and just 0.13″ at O’Hare. But weekend rain tallies increased as one traveled south with Midwest picking up 0.67″.

While Saturday saw just 16% of its possible sun and Sunday came in with just 14% of its possible sun. Monday was modestly better, hosting 47% of its possible sunshine.

Happily, there’s been a MODEST improvement in the MOLD AND WEED POLLEN counts from Loyola Medicine Monday—with MOLD coming in “MODERATE” and WEEDS coming in “LOW”. Both were MODERATE TO HIGH last week.

ACTIVE ADVISORIES

OVERNIGHT WEATHER MONDAY, WARMER TUESDAY

TUESDAY’S PREDICTED CLOUD COVERAGE

WEEKLY FORECASTED TEMPERATURES

STORM CHANCES FOR THE COMING WEEK

MAMMOTH EASTERN U.S. SEVERE WEATHER OUTBREAK MONDAY
Severe storms have swept 17 states from Alabama and Georgia north to New York–including the Washington, Baltimore, Philadelphia and New York metropolitan areas producing widespread damage knocking out power to 788,000 late Monday evening. More than 500 severe storm reports have been filed with the National Weather Service’s Storm Prediction Center (SPC).

The weather system responsible for our cloudy, windy, wet weekend weather here in Chicago and the Midwest is behind the severe weather outbreak.

HERE ARE SOME PEAK WIND GUSTS RECORDED IN THE EASTERN U.S. MONDAY:
71 mph Atlanta Peachtree Airport
60 mph Chattanooga, TN
59 mph Manassas, VA
58 Fayetteville, NC
56 mph Quantico Airfield, VA
55 mph Philadelphia, PA
54 Allentown, PA
52 mph Reagan National Airport-Washington DC
52 mph Baltimore, MD
48 mph Florence, SC

HAWAII’S WAVE HEIGHTS
Significant waves heights are defined by oceanographers and meteorologists as, “…..the average of the highest one-third of the waves, as measured from the trough to the crest of the waves.”

HURRICANE DORA
A formidable CAT4 HURRICANE with 140 mph sustained winds
Hurricane Dora is currently located 1,115 miles east/southeast of South Point, Hawaii–the southernmost point on the Big Island. It is to pass well south of the Hawaiian Islands–but remaining, as it will, over warm Pacific waters, the hurricane is to maintain its strength and is kicking out some formidable Pacific swells. That–plus the fact the storm will act to “tighten” the pressure gradient with the huge sub-tropical high pressure to its north—means easterly trade winds will increase across the Islands. This has prompted HIGH WIND WATCHES on the islands higher elevations.

DORA’S ARRIVAL TIME

HURRICANE DORA: OCEAN HEAT
Ocean heat content analysis shows how Hurricane Dora’s projected track will keep the storm over energy-rich Pacific ocean waters which will help the storm to maintain strength. Many hurricanes which approach the Hawaiian hurricane encounter the cooler ocean waters to the north sapping their energy–but NOT Dora.

HURRICANE DORA: OVER THE NEXT 5 DAYS
The path and estimated tropical storm force (and greater) winds with Hurricane Dora over the coming 5 days.

Nighttime camera views of our weather are possible on current generation weather satellites–including the NOAA-20 POLAR ORBITING WEATHER SATELLITE

“POLAR ORBITING” SATELLITES MOVE move continuously from pole to pole as Earth rotates below. They are able to produce high resolution images from an altitude averaging 516 miles above Earth.

In years past, nighttime satellite views of the weather actually FALSE COLOR IMAGES. They were produced–NOT by cameras, but by using measurement of temps measured with weather satellite heat sensors–then inferring where clouds were located from the temp data.

BY CONTRAST, THIS IMAGE is an actual NIGHTTIME PHOTO of powerhouse Hurricane Dora tracking well south of Hawaii. Moonlight illuminates the clouds. This photo is courtesy of the folks at CIRA-RAMBB. The image was created at 1:03am Hawaii time Monday morning (that’s 6:03am Chicago time Monday).