United boss Steven Pressley made just one change form Saturday's game against Swindon with Kelvin Etuhu coming into the starting line up in place of the injured Mark Cullen.
The Blues were looking to make it back-to-back victories against the troubled Magpies, but Storm Gareth made things interesting as driving rain and howling winds battered Brunton Park.
Captain Danny Grainger won the toss and opted to kick into the wind - with reported gusts of 70 miles-per-hour and stronger - which meant the Blues were attacking the Warwick Road End through the first half.
A free kick on three minutes from United's left back from wide on the flank had to be watched by Schofield as it swirled and skipped off the surface. He held his position and comfortably pulled it into his midriff.
Good football saw the hosts switch the ball from left to right as Devitt found Slater. He played Scougall into a good area, and a reverse pass released Liddle as he strode forward to overlap. He crossed early but Schofield was there was once again.
The Magpies took advantage of some awkward ricochets when Carlisle were caught deep and Boldewijn was suddenly played into space. A fierce low shot was parried by Collin, but the wide man was first to react to the loose ball. His instinctive shot whistled just over the bar.
Another free kick from the left flank, this time from Devitt, went the same way as Grainger's earlier effort as Schofield gobbled it up. Adam Collin did the same at the other end when Doyle bent one in on the wind moments later.
A miskick from Liddle when he had the ball at his feet inside his own penalty area caused all kinds of problems as Alessandra was left with a free run at goal. Fortunately for the United right back the forward lost his bearings and the final delivery was woeful.
More hesitancy from the Carlisle defence brought County forward in numbers, and Liddle had to block a cross from Hemmings away for a corner. That was looped high, and Collin lost the flight as it caught in the wind. It seemed to take an age for Parkes to step in and slam it behind to safety.
The Cumbrians struggled to deal with the wind in their faces as it grew in strength and O'Brien was next to have a go when a long throw was chested into his path. His volley had power but it was always heading wide.
County were a whisker away from taking the lead just past the half hour when Doyle curled a wicked free kick into the mix. Parkes stretched out a leg and he was relieved to see it fall wide of the post.
Doyle followed up with two excellent corners with Collin's penalty box packed with almost every outfield player. Gerrard cleared the first one and the second dropped onto the roof of the net.
Keeper Adam Collin pulled off a fantastic save on 35 minutes when Doyle zipped another teasing free kick in on the wind. It skimmed off heads and appeared to be about to bulge the bottom corner until the big stopper somehow got down to palm it away.
But the visitors were gifted a goal on 37 minutes when Gary Liddle underhit a back pass as he came under pressure. Collin raced out to block the first shot, but the ball spooned high and Hemmings was able to tap it home at the second time of asking as it fell kindly on his boot.
A long range effort from O'Brien dipped just over the bar as the Magpies continued to use the wind to their advantage, but Carlisle almost pulled one back just before the break when Slater clipped a pass behind the back line for Hope to chase. He cut back inside and fed it through for the late arriving Danny Grainger to strike, but Schofield parried it and snapped it up at the second attempt.
United tried to use the wind to their advantage at the start of the second half when Grainger placed the ball for a free kick. He kept it low and hit it hard but it was straight at Schofield.
Better came from the Blues when a Scougall cross was half cleared. Grainger charged it down and Slater set his sights with a 25-yard shot. It flew past Schofield but was wide of the mark.
County had good moments of their own as they attacked with confidence and corner deliveries from Doyle remained a thorn in the side. The Blues twice had to battle to clear as he dropped them into the six-yard box.
A cross from Alessandra was just too far in front of Boldewijn as Carlisle continued to send their passes astray, and the set piece deliveries which followed proved to be another big test for the Blues as Gerrard lunged in on Duffy, with the referee quickly pointing to the spot, much to the disappointment of the Carlisle players.
Hemmings placed the ball and he doubled the lead, and his own tally for the night, with a thumping and unstoppable penalty kick.
Carlisle needed a spark, and Gerrard tried to provide it when he let fly from distance. The ball hit a defender and was deflected away for a corner.
The boost came as the hosts got right back in it with 15 minutes left to play when Notts County keeper Ryan Schofield forgot to check behind as he placed the ball on the floor in readiness to kick it long. Hallam Hope was lurking, and he made it 13 for the season as he sprinted out of nowhere to nick the ball before stabbing into the empty net.
Former Magpie Nathan Thomas was denied an equaliser when he tried to crunch a shot from an angle past the keeper. An outstretched hand was just enough to send it behind. And Thomas was even closer when he stepped in to take control of a scramble out wide. His rasper of an inswinger was tipped over by Schofield before it could make it into the top corner.
United stayed on the front foot and the slightest of touches from the away stopper denied Simpson a tap-in as he arrived late at the back stick.
Hope wasted a good opening when he opted to shoot, with runners left and right, and he lost his balance at the wrong moment to send his toe poke wide.
The Magpies were able to run the clock down as they got forward with Hemmings in possession, and they wrapped it up deep into time added on when Collin went forward for a late free kick. A clearance left Lewis Alessandra all alone and he was able to carry the ball on and tuck it away into the empty net.
That left the Cumbrians to ponder a contest where they took too long to get themselves going as they slipped frustratingly out of the play-off places.
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Goals
Carlisle United - Hope (76)
Notts County - Hemmings (37 & 66 pen), Alessandra (90)
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Bookings
Carlisle United - Gerrard (66), Devitt (90)
Notts County - Milsom (23), Hemmings (65), Rose (87), O'Brien (90)
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Teams
Carlisle United - Collin, Liddle, Gerrard, Parkes, Grainger (Simpson 71), Slater, Etuhu, Scougall (Thomas 56), Devitt, Hope, O'Hare. Subs - Gray, Miller, Kennedy, Jones, Grant.
Notts County - Schofield, Duffy, Alessandra, Vaughan, Boldewijn (Bird 81), Hemmings, Stubbs, O'Brien, Milsom, Rose, Doyle. Subs - Fitzsimons, Tootle, Barclay, Gomis, Patching, Etete.
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Referee - Mr Eddie Ilderton
Attendance - 3,514 (151 away fans)