Hurricane Florence: 5 PM Monday Update

As of 4:00 PM CDT, Hurricane Florence remains a Category 4 Hurricane with sustained winds of 140 mph and gusts up to 165 mph. This places her in the middle of the Category 4 threshold.


As has been the case for most of the day, Florence continues to undergo rapid intensification. As of the latest update, Florence's central pressure has dropped to 939 millibars (mbs), which means it is a very strong low pressure system. In addition to the pressure drop, and due to the increase in the overall wind speeds, Florence's hurricane force winds now extend roughly 40 miles from the center.

Recent computer model guidance, along with current observations across the Atlantic environment, indicate that Florence is not done intensifying, and may reach very close to Category 5 intensity within the next 24 hours. But will she be this strong at landfall? Well, there are a few factors that may play against her favor.

First off is the "Eye replacement cycle" which is a common occurrence within many long-lived hurricanes. Basically, the eye of the hurricane undergoes a recycling process, which causes the hurricane to temporarily weaken a little bit. This may end up being the case when Florence nears landfall given the fact that she is such a long-lived hurricanes. Many hurricanes in their longevity can undergo this process two or three times on average during their lifetime.

Second off, right now Florence is a low shear environment; which means the atmospheric winds are not changing very much. Hurricanes like this, as it allows them to continue to intensify, but as Florence nears the North Carolina shoreline, the wind shear may increase a little bit, which may cause Florence to weaken a little bit before landfall.

So how strong may Florence be at landfall? At this time, it is difficult to tell. But latest guidance suggests that she will be at Category 4 intensity with winds between 140 mph and 150 mph, with even higher gusts.

In the previous post, I mentioned how when a hurricane weakens a little bit, it's wind field expands, and this may be the overall case, even if Florence only weakens a little bit.

As of right now, it appears that Florence will start picking up some speed as she rounds the base of a ridge of high pressure over the Atlantic. This means she will probably make landfall sometime on Thursday Afternoon or Thursday Evening.

Lastly, keep in mind that when a hurricane makes landfall, they begin to weaken very quickly. Often times what happens is that the ocean waters (which offer little friction to air) are where the winds will be highest, but the further you go inland, the more friction takes over and weakens the winds. This means that, although Florence may be a Category 4 Hurricane at landfall, it is entirely possible that most of the impacted areas will not see much of the 140 - 150 mph winds (especially further inland).

As of now, there are currently no watches or warnings in effect for the East Coast with regards to Hurricane Florence, however a hurricane watch may be issued on Tuesday Morning for the coasts of South Carolina and North Carolina.

-Timothy Albertson

Hurricane Florence: Afternoon Update

Hurricane Florence continues to rapidly intensify as she enters an atmosphere that is rather favorable for hurricanes. As of the 10:00 AM CDT, Hurricane Florence was upgraded to a Category 3 Hurricane with sustained winds of 115 mph; however, satellite data and data from the Hurricane Hunters revealed that Florence's intensity had increased to that of a Category 4 Hurricane with sustained winds around 130 mph at 11:00 AM CDT.
At 10:00 AM CDT, Florence's barometric pressure was at 962 millibars (mbs), however an hour later the pressure had plummeted to 946 mbs. This is a rather fast drop for a hurricane, especially given the amount of time in which it had occurred.

What does this mean? It means that Hurricane Florence is on track to become this season's most powerful hurricane (pending no other hurricane reaches this same intensity before the end of Hurricane season).

On the satellite image, Hurricane Florence looks rather large, but as is the case with all hurricanes: looks are deceiving. It is important to note that not all of the hurricane contains the 130 mph winds. In fact, only a small portion of the hurricane contains these winds, and that is an area extending roughly 30 miles out from the eye of the hurricane in what is known as the "eye wall". The eye wall of a hurricane is where the strongest winds can be found, and this is often the area where the most damage from the hurricane occurs.

When a hurricane undergoes rapid intensification, it becomes "compact", resulting in a hurricane force wind radius that is rather small compared to the overall size of the hurricane. When the hurricane begins to weaken, the strongest winds begin to extend out further from the center (albeit, they are weaker than what they would be before the hurricane began weakening). Think of an ice skater (a hurricane) pulling his/her arms (hurricane force winds) inwards; the more the arms are brought inwards (a hurricane intensifying) the faster the skater spins (the winds of a hurricane), but notice how it is a small area. Conversely, when the skater extends their arms outwards (hurricane begins to weaken) the skater's spin slows down (the winds extend further out from the center, but are weaker).

So what can we expect from Florence over the next few days? Florence is expected to maintain her Category 4 intensity. Given the atmospheric lay out across the Atlantic Ocean, Florence appears poised to hit the southern shores of North Carolina.

Is this a record? Well, it may be a record for the specific town that receives the land fall, but as we know the Mexico/U.S./Canada East Coasts are no stranger to strong hurricanes striking them.

Florence is currently moving westwards at 13 mph and is located roughly 575 miles southeast of Bermuda. Florence is expected to make a landfall in North Carolina sometime on Thursday.

At this time, no watches or warnings are in effect for the mainland U.S. with regards to Hurricane Florence.

Stay tuned for more updates.

-Timothy Albertson

Pesky Gordon Finally Moves East . . .

Our Stateline weather for the past week has been dominated by rain, instability and changing temperatures - add to that a Tropical Depression and you have the makings of an unsettled week.  The good news is that Tropical Depression Gordon (which dropped nearly 10 inches of rain in Pensacola, Florida), is finally moving east and will have less of an impact on our weather for our Sunday.  The main effects here have been clouds, cool temperatures and breezy conditions (some gusts around 29 mph).  We've spent 3 days with below normal temperatures (78 degrees our normal high) as well that makes it feel like Autumn is coming very soon.  Sunday should be a better day with more sunshine and warmer temperatures, although it will still be breezy with some gusts up to 25 mph. 

As we move into next week, the picture continues to improve with plentiful sunshine and gradually increasing temperatures that should go above 80 by Wednesday.  With a very active Atlantic storm cycle (Florence may make landfall by Thursday in The Carolinas), this may not be the last Tropical Storm to impact our weather this Fall!  Have a great Sunday!  

Heaviest Weekend Rain Falls Just to the South

Skies were filled with cloud cover Thursday afternoon but the sun did make an appearance, and actually made for a fairly comfortable evening, across much of northern Illinois.  Outside of a very light shower or sprinkle, skies will remain partly cloudy through the early overnight.

A weak disturbance moving in from Iowa by Friday morning will bring back the chance for light showers during the morning commute, but like Thursday the heaviest rainfall shifts southward throughout the afternoon.

The remnant low pressure system from what was Tropical Storm Gordon will continue to lift north through Arkansas and Missouri.  This low will then move east across southern Illinois and Indiana by Saturday night and Sunday morning.  Extremely high amounts of moisture will be pulled northward bringing significant rainfall to parts of Missouri and Illinois.  In fact, totals could reach near five to six inches by Sunday night.  Flash Flood Watches have been issued to the south as a result.

While it looks like the more southern track will take hold, it's possible that the low may come a little closer to east-central Illinois Saturday evening and Saturday night.  If so, this would bring rain northward through early Sunday morning.  While it wouldn't be as much locally as what will fall to the south, the rain would continue to slow the rivers that have already started to recede.

Right now the forecast calls for mostly cloudy skies, temperatures in the low 70's and a slight chance for rain late Saturday.

Thursday Afternoon Flood Forecast Update

Several rounds of heavy rain showers and thunderstorms over the past week has resulted in some river flooding. While a lot of rain has fallen in Rockford, the places upstream in Wisconsin have seen even more rain. All of that water is finally making its way into the local rivers here in our area, and many will be cresting within the next 24 to 48 hours.
Flood warnings are in effect for several area rivers including the Kishwaukee River in Boone and Winnebago counties, the Rock River and the Pectonica Rivers. Flooding will occur at the following areas (including but not limited to):

Flood Warnings remain in effect for the following areas (including to, but not limited to):

KISHWAUKEE RIVER at PERRYVILLE (WINNEBAGO COUNTY, IL)
PECATONICA RIVER at FREEPORT (STEPHENSON COUNTY, IL)
PECATONICA RIVER at SHIRLAND (WINNEBAGO COUNTY, IL)
ROCK RIVER at AFTON (ROCK COUNTY, WI)
ROCK RIVER at BYRON (OGLE COUNTY, IL)
ROCK RIVER at LAKE KOSHKONONG (ROCK/JEFFERSON COUNTY, WI)
ROCK RIVER at LATHAM PARK (WINNEBAGO COUNTY, IL)
ROCK RIVER at ROCKTON (WINNEBAGO COUNTY, IL)

MINOR FLOOD STAGE AREAS INCLUDE:

Kishwaukee River at Perryville is currently above flood stage with a water height of 12.4 feet. The water levels are receding and should be below flood stage by this afternoon.


Pecatonica River at Freeport is currently above flood stage with a water height of 13.5 feet. The river will continue to rise until Friday Morning, cresting at a height of 13.6 feet. The river is expected to drop below flood by Monday Evening.

Pecatonica River at Shirland is currently above flood stage with a water height of 13.7 feet. The river is expected to continue to rise until Friday Morning, cresting at a height of 13.9 feet.

MODERATE FLOOD STAGE AREAS INCLUDE:


Rock River at Afton is currently above flood stage with a water height of 10.6 feet. The river is expected to continue to rise to 11.7 feet on Monday and should remain near that height until Tuesday.

Rock River at Byron is currently above flood stage with a water height of 14.0 feet. The water is expected to gradually recede over the next couple of days, dropping to minor flood stage by this evening, and then below flood stage by Monday or Tuesday. 

Rock River at Latham Park is currently above flood stage with a water height of 10.7 feet. The river is expected to continue to rise until Sunday Afternoon, cresting at a height of 11.7 feet.

Rock River at Rockton is currently above flood stage with a water height of 10.4 feet. The river is expected to continue to rise until Monday Morning, cresting at a height of 11.6 feet.

MAJOR FLOOD STAGE AREAS INCLUDE:

Rock River near Lake Koshkonong is currently above flood stage with a water height of 10.6 feet. The river is expected to continue to rise until at least Tuesday Morning with a water height of 11.9 feet.

-Timothy Albertson

Thursday Morning Flood Forecast Update

This list will be updated throughout the morning with additional river flooding and updated water heights.

Several rounds of heavy rain showers and thunderstorms over the past week has resulted in some river flooding. While a lot of rain has fallen in Rockford, the places upstream in Wisconsin have seen even more rain. All of that water is finally making its way into the local rivers here in our area, and many will be cresting within the next 24 to 48 hours.

Flood warnings are in effect for several area rivers including the Kishwaukee River in Boone and Winnebago counties, the Rock River and the Pectonica Rivers. Flooding will occur at the following areas (including but not limited to):

KISHWAUKEE RIVER at BELVIDERE (BOONE COUNTY, IL)
KISHWAUKEE RIVER at PERRYVILLE (WINNEBAGO COUNTY, IL)
PECTONICA RIVER at SHIRLAND (WINNEBAGO COUNTY, IL)
ROCK RIVER at ROCKTON (WINNEBAGO COUNTY, IL)
ROCK RIVER at LATHAM PARK (WINNEBAGO COUNTY, IL)
ROCK RIVER at BYRON (OGLE COUNTY, IL)
ROCK RIVER at AFTON (ROCK COUNTY, WI)
ROCK RIVER at NEWVILLE (ROCK COUNTY, WI)
ROCK RIVER at LAKE KOSHKONONG (JEFFERSON/ROCK COUNTY, WI)

MINOR FLOOD STAGE AREAS INCLUDE:

Pectonia River at Shirland is currently experiencing minor flooding with a current water height of 13.5 feet. The river will crest Friday Morning at 13.8 feet. Flood stage is at 12.0 feet.

Kishwaukee River at Perryville is currently experiencing minor flooding with a current water height of 13.9 feet. The river has already crested and will continue to see water heights drop to below flood stage by this afternoon. Flood stage is at 12.0 feet.

MODERATE FLOOD STAGE AREAS INCLUDE:

The Rock River at Byron is currently experiencing moderate flooding with a current water height of 14.3 feet. Cresting is occurring this morning.

Rock River at Latham Park is currently experiencing minor flooding with a current water height of 10.7 feet. The river will reach moderate flood stage as it crests to a height of 11.7 feet by Saturday Morning. Flood stage is at 10.0 feet.

Rock River at Rockton is currently experiencing minor flooding with a current water height of 10.1 feet. The river will reach moderate flood stage as it crests to a height of 11.5 feet by Saturday Morning.

Rock River at Afton is currently experiencing minor flooding with a current water height of 10.4 feet. The river will reach moderate flood stage this morning as it crests to a height of 11.7 feet. 

MAJOR FLOOD STAGE AREAS INCLUDE:

The Rock River near Lake Koshkonong is experiencing minor flooding with a current water height of 10.5 feet. The river will reach major flood stage on Tuesday Morning.

-Timothy Albertson

Flood Forecast Update

Several rounds of heavy rain showers and thunderstorms over the past week has resulted in some river flooding. While a lot of rain has fallen in Rockford, the places upstream in Wisconsin have seen even more rain. All of that water is finally making its way into the local rivers here in our area, and many will be cresting within the next 24 to 48 hours.

Flood warnings are in effect for several area rivers including the Kishwaukee River in Boone and Winnebago counties, the Rock River and the Pectonica Rivers.

Areas of Minor Flood Stage include:

The Pectonica River at Shirland will crest at 13.2 feet. This is just slightly above the flood stage of 12.0 feet. The river will crest on Thursday Morning and then begin to recede.

The Pectonica River at Freeport will crest at 13.3 feet. This is slightly above the flood stage of 13.0 feet. The river will crest later today, and then recede to below flood stage by Friday Morning.

The Rock River in Rockton will crest at 10.4 feet, this is just slightly above the flood stage of 10 ft. This crest will occur on Friday Morning before the waters begin to recede.

The Rock River at Latham Park is expected to crest at 10.7 feet, this is slightly above the flood stage of 10 ft. Some back yards and places along the river are expected to flood (if they have not yet already). This crest will occur Friday Morning, and then the waters will gradually begin to recede.

The Rock River at Afton is expected to crest at 10.7 feet, this is above the flood stage of 9.0 feet. This crest will occur over the weekend, and then the waters will begin to recede to below flood stage sometime mid-next week.

The Rock River at Como will crest at 13.4 feet. This is slightly above the flood stage of 12.5 feet. This crest will occur later today before the waters begin to recede to below flood stage by Saturday Morning. 

Areas of Moderate Flood Stage include:

The Rock River at Byron will crest at 14.3 feet on Saturday Morning, this is above the flood stage of 13.0 feet. Currently, the Rock River at Byron is at 14.2 feet.

The Rock River at Joslin will crest at 16.1 feet on Thursday Morning, this is above the flood stage of 12.0 feet.

The Kishwaukee River at Belvidere is currently at 11.3 feet, which is well above the flood stage of 9.0 feet. Flooding of this area will continue as the river reaches it's crest today. The river will then begin to recede and the Kishwaukee River at Belvidere should go below flood stage by Thursday Morning.

No Major Flooding or Record Flooding is expected at this time in our area.

-Timothy Albertson